Received: 01 July 2015 / Accepted: 19 November 2015 / Published online: 01 December 2015
From glacial refugia to wide distribution range: demographic expansion of Loropetalum chinense (Hamamelidaceae) in Chinese subtropical evergreen broadleaved forestDownload PDFAbstract
The subtropical evergreen broadleaved forest (STEBF) in China is globally one of the most diverse and biologically important forest systems. There has been a long-term debate whether this region was affected dramatically during Pleistocene glaciation and deglaciation cycles, e.g., in terms of range dimensions and changes in species richness. Here we report a large-scale phylogeographic study, focusing on a widespread and typical constituent species of the Chinese STEBF, Loropetalum chinense (R. Br.) Oliver (Hamamelidaceae). In total, 56 populations spanning the entire distribution range of L. chinense were analyzed. Chloroplast DNA sequence variation and AFLPs as molecular marker systems were used in combination with ecological niche modeling (ENM). ENM indicated that the distribution ranges of L. chinense were contracted remarkably and most populations retreated southward. Thereby, based on ENM, geographical distribution pattern of cpDNA haplotypes, and AFLP genetic clusters, one glacial refuge was inferred in the Nanling Mountains in southern China, and a second glacial refuge was identified in Three Gorges Area and Dabashan Mountains in Chongqing Province, southwestern China. In addition to ENM, with mismatch distribution analysis and Bayesian skyline plots, demographic expansion was inferred to take place about 10.6 kya. The current geographic distribution pattern of genetic variation might be shaped by northward and eastward expansion along Nanling Mountains and Wuyishan Mountains, respectively. Additionally, the two mountain ranges were supposed to act as geographical barriers restricting gene flow between the southern and northern populations. Herewith, we aim to further contribute a case study of the phylogeographic history of this vegetation type, which will help to improve deeper understanding of past vegetation dynamics and floristic evolutionary pathways of the Chinese STEBF.
Received: 10 July 2015 / Accepted: 27 August 2015 / Published online: 07 September 2015
New animal phylogeny: future challenges for animal phylogeny in the age of phylogenomicsDownload PDFAbstract
The science of phylogenetics, and specially the subfield of molecular systematics, has grown exponentially not only in the amount of publications and general interest, but also especially in the amount of genetic data available. Modern phylogenomic analyses use large genomic and transcriptomic resources, yet a comprehensive molecular phylogeny of animals, including the newest types of data for all phyla, remains elusive. Future challenges need to address important issues with taxon sampling—especially for rare and small animals—orthology assignment, algorithmic developments, and data storage and to figure out better ways to integrate information from genomes and morphology in order to place fossils more precisely in the animal tree of life. Such precise placement will also aid in providing more accurate dates to major evolutionary events during the evolution of our closest kingdom.
Received: 31 August 2015 / Accepted: 09 February 2016 / Published online: 14 March 2016
Dispelling five myths about hypothesis testing in biological systematicsDownload PDFAbstract
The emphasis on testing phylogenetic hypotheses has been prominent since the English language introductions of Willi Hennig’s Phylogenetic Systematics (1966) and Karl Popper’s (1959) Logic of Scientific Discovery. While the mechanics of hypothesis and theory testing are well established in other fields of science, adherence to those prescriptions in biological systematics has rarely been formally recognized. The consequence has been the development of potentially contradictory approaches to empirically evaluating phylogenetic hypotheses under the guise of testing. In his brief review of the topic, Assis (Cladistics, 30:240–242, 2014) identified five different views on phylogenetic hypothesis testing: (1) total evidence, (2) taxonomic congruence, (3) reciprocal illumination, (4) homology assessment, and (5) taxa sampling. The present paper examines the validity of these views against the actual inferential steps required to infer hypotheses and subsequently engage in testing, i.e., abduction, deduction, and induction (sensu stricto), respectively. It is shown that none of the tests discussed by Assis are valid, and while it is straightforward to outline what is required to properly test phylogenetic hypotheses, the feasibility of accomplishing such tests is operationally impractical in most instances.
Received: 16 October 2015 / Accepted: 26 January 2016 / Published online: 05 February 2016
Ultrastructural differences in presumed photoreceptive organs and molecular data as a means for species discrimination in Polygordius (Annelida, Protodriliformia, Polygordiidae)Download PDFAbstract
Members of Polygordiidae Czerniavsky, 1881 are distributed worldwide and are typical inhabitants of coarse grained, marine sublittoral sediments. Species in Polygordiidae are unusual among polychaetes because they lack external segmentation, parapodia, and chaetae as well as external ciliation. Morphological characters for species distinction are thus limited to the shape and minute structures of the prostomium and pygidium. As a result, morphological identification and description of the Polygordius species is difficult. In the present study, we provide new data for species distinction using molecular and morphological methods, i.e., DNA-sequencing (COI gene), transmission electron microscopy (TEM), and confocal laser scanning microscopy (cLSM). Specifically, we investigated whether the photoreceptor-like sense organs, previously described for Polygordius appendiculatus Fraipont, 1887, could provide additional characters of taxonomic value by examining the ultrastructure of these organs in two additional species, Polygordius erythrophthalmus Giard, 1880 and Polygordius lacteus Schneider, 1868. These organs were found to occur in comparatively large numbers and comprise different types of sensory cells including one rhabdomeric and two ciliary, which are variously combined to form small sensory organs. Structural differences in sensory organs were negligible between P. erythrophthalmus and P. lacteus; however, major differences were observed when compared to P. appendiculatus. These results are in accordance with our molecular data which indicated that P. erythrophthalmus and P. lacteus represent the same species. Thus P. erythrophthalmus is an invalid species and represents a junior synonym of P. lacteus. Furthermore, this study shows that ultrastructural data can significantly contribute to species distinction, especially in morphologically similar species.
Received: 26 September 2015 / Accepted: 10 October 2015 / Published online: 27 October 2015
A study of common scorpionfly (Mecoptera: Panorpidae) visual systems reveals the expression of a single opsinDownload PDFAbstract
Knowledge of insect color vision and the genes that support color vision has been growing recently. Yet, research on some groups is limited (e.g., Mecoptera). Common scorpionflies (Panorpidae) are highly visual insects with many intriguing behaviors. We hypothesized that the family Panorpidae employs a complex color vision system and predicted that multiple opsin classes are expressed in the lineage. Transcriptomes were generated from the eye tissues for two species of Panorpidae (Panorpa acuminata and P. nebulosa) and one species of Boreidae (Boreus coloradensis). Opsins isolated from the transcriptomes were combined in a phylogenetic analysis with opsin sequences from other insect orders (e.g., those that are sensitive to ultraviolet, blue, and long wavelength light as part of the photopigment). A single long-wavelength opsin sequence was recovered from the panorpid species, while all three opsin classes (ultraviolet, blue, and long-wavelength) were recovered from the boreid. Among insects, this represents a potential case of monochromy due to a loss of opsin gene expression in the blue and ultraviolet portions of the visible light spectrum.
Received: 31 January 2015 / Accepted: 18 August 2015 / Published online: 10 September 2015
Pseudamnicola Paulucci, 1878 (Caenogastropoda: Truncatelloidea) from the Aegean Islands: a long or short story?Download PDFAbstract
The aims of the study were (i) to reveal the pattern of phylogeny of Pseudamnicola inhabiting the Aegean Islands, (ii) to describe and analyse the variation of the morphology in 17 populations of Pseudamnicola from the springs on the Aegean Islands not studied so far and considering also another seven populations studied earlier and (iii) to find out which model is more applicable to the island Pseudamnicola populations: either a model in which a relict fauna rich in endemics is differentiated in a way that mainly reflects the geological history of the area or a model in which a relatively young fauna is composed of more or less widely distributed taxa, with relatively high levels of gene flow among the springs they inhabit. To address the above issues, the morphology and the mitochondrial genes—cytochrome oxidase subunit I (COI) and ribosomal 16S—and nuclear genes—ribosomal 18S, 28S and histone 3 (H3)—were analysed. COI and COI+16S rRNA+18S datasets gave trees with identical topology in both ML and Bayesian inference. The 24 studied populations of Pseudamnicola form 16 clades, each of them generally having low levels of intrapopulation genetic differentiation. The generalised mixed Yule coalescent (GMYC) procedure and the Automatic Barcode Gap Discovery (ABGD) analysis for COI identified 16 Pseudamnicola entities coinciding with clades of the ML tree based on 44 haplotypes and 189 sequences. The present pattern of diversity, together with dating of divergence time, reflects a short story of colonisation/recolonisation, supported by the Late Pleistocene land bridges, rather than the consequences of earlier geological events. The principal component analysis (PCA) on the shells of the molecularly distinct clades showed differences, although variability ranges often overlap. Female reproductive organs showed no differences between the clades, and penile characters differed only in some cases.
Received: 11 March 2015 / Accepted: 26 January 2016 / Published online: 07 March 2016
Molecular data in conjunction with morphology help resolve the Hemidactylus brookii complex (Squamata: Gekkonidae)Download PDFAbstract
Molecular data are increasingly being used to resolve cryptic species complexes; however, subsequent formal species description and taxonomic revisions often remain incomplete. Given that most species are described based on morphology-based alpha taxonomy, one cannot resolve nomenclatural issues of species complexes without the aid of morphology. In this study, we examined the taxonomic status of a long-known human commensal and species complex, Hemidactylus brookii. To this end, samples of H. cf. brookii and related species were collected across India. We analyzed molecular as well as morphological data to resolve the taxonomy of this species complex. Seven deeply divergent, well-supported clades were recovered using the mitochondrial phylogeny, five of which were also retrieved in the nuclear tree. One of these consists of five morphologically distinct species of ground-dwelling Hemidactylus. The genetic distances across each clade of putative species of H. brookii sensu lato were comparable to that between morphologically distinct species of ground-dwelling Hemidactylus. Meristic characters such as number of precloacal-femoral pores, number of non-pore bearing scales interrupting the series of pored scales, dorsal pholidosis, and presence/absence of divided lamellae can be used to distinguish these putative species from each other. However, morphological characters of H. brookii sensu stricto did not correspond to any of the putative species studied. The study also revealed that the “H. brookii complex” in India includes two commensal species, Hemidactylus parvimaculatus and Hemidactylus murrayi. Furthermore, these two lineages have independently acquired adaptations that could have assisted them in exploiting human habitat. An identification key to diagnose species within this complex and rest of the Hemidactylus in India is proposed.
Received: 11 July 2016 / Accepted: 17 July 2016 / Published online: 01 August 2016
Again on the meaning of categorial ranks in modern evolutionary biology?Download PDF
Received: 14 July 2015 / Accepted: 21 January 2016 / Published online: 05 February 2016
Update of genetic information for the white-clawed crayfish in Spain, with new insights into its population genetics and originDownload PDFAbstract
The white-clawed crayfish is endemic to western and southern Europe and its populations have decreased over recent decades. Spanish populations are generally poorly represented in scientific reports and are usually studied only with a single molecular marker. Here, we use two mitochondrial markers (cytochrome oxidase subunit I and rDNA 16S genes) to examine levels and patterns of genetic structure across the range of the species’ distribution in Spain. Data reveal the existence of two main genetic groups of white-clawed crayfish in Spain with the Ebro basin as a possible contact zone. Processes occurred in historical and recent times, such as genetic drift and translocations, contribute greatly to this genetic structure. Levels of genetic variability and genetic structure of Spanish populations together with demographic inferences suggest that the species established in the Iberian Peninsula, at least since the Late Pleistocene. Knowing the true origin of the Spanish populations is crucial when deciding upon the management policies that should be followed. Given the lack of any clear evidence against its indigenous status, we propose that current protection and conservation measures should be maintained. From a management point of view, we suggest that Spanish population should be considered as a single evolutionary significant unit (ESU) with two management units (MUs) corresponding with the genetic clusters detected in the present study.
Received: 13 July 2016 / Accepted: 22 July 2016 / Published online: 15 August 2016
The white-clawed crayfish in Spain—reply to Clavero and Centeno-CuadrosDownload PDF
Received: 17 February 2016 / Accepted: 02 April 2016 / Published online: 22 April 2016
The phylogenetic system of primates—character evolution in the light of a consolidated treeDownload PDFAbstract
Molecular analyses of the last decades helped solving the major open questions on the external and internal phylogenetic relationships of primates. The present review uses these data for the inference of character evolution along the branches of the primate tree. Altogether, more than 200 evolutionary changes in hard and soft tissue anatomy/morphology, behavior, physiology, and protein constitution are presented in the context of their functional relevance and adaptive value. The compilation focuses on primates as a whole and on the higher-ranked primate subtaxa with living representatives: Strepsirhini: Lorisiformes, Galagidae, Lorisidae, Lemuriformes; Haplorhini: Tarsioidea, Anthropoidea, Platyrrhini, Atelidae + Cebidae, Atelidae, Cebidae, Aotinae, Callithrichinae, Cebinae, Pitheciidae, Pithecinae, Catarrhini, Cercopithecoidea, Cercopithecinae, Colobinae, Colobini, and Hominoidea. Within Hominoidea character evolution is traced down to more peripheral branches: Hylobatidae, Hominidae, Pongo, Homininae, Gorilla, Pan + Homo, Pan, and modern humans. Character states in extinct representatives of Plesiadapiformes, Omomyoidea, Propliopithecidae, Hominini, etc. are always taken into account; they are presented in detail whenever character-state distribution in living species is ambiguous or misleading. The taxonomic sample and the characters included combine to a phylogenetic system that illustrates primate evolution and diversity. The data presented additionally provide a detailed picture of the evolutionary steps and trends involved in hominization. Reflections on the frequently underestimated role of polymorphisms in phylogenetic analyses complete the survey.
Received: 22 September 2015 / Accepted: 01 February 2016 / Published online: 12 February 2016
Evaluation of traditionally circumscribed species in the lichen-forming genus Usnea, section Usnea (Parmeliaceae, Ascomycota) using a six-locus datasetDownload PDFAbstract
Recent taxonomic and DNA sequence-based studies in several groups of lichen-forming fungi have revealed incongruence between the morphological and molecule-based circumscriptions of species. While the cosmopolitan genus Usnea is well-known and easily recognized by the yellowish beard-like thallus with central cord, delimitation of many Usnea species is difficult due to the high variation and complexity of diagnostic characters. In this study, we assessed the monophyly of 18 species from section Usnea occurring in North America and Europe, including sorediate and sexually reproducing taxa with both pendent and shrubby thalli. Six nuclear markers (ribosomal internal transcribed spacer (ITS) and intergenic spacer (IGS), and protein-coding beta-tubulin, MCM7, RPB1 and RPB2) were sequenced for 144 samples. All analyzed loci show weak genetic structure and short branch lengths in single-locus topologies, suggesting recent diversification history of the sampled taxa. Concatenated, multi-locus analyses conducted in Bayesian and maximum likelihood frameworks, as well as coalescent-based species delimitation and species tree methods, recover several distinct clades, some represent traditional morphology-based species (Usnea cavernosa, U. praetervisa, U. silesiaca, U. wasmuthii), while others form clusters of two or more species (Usnea florida–U. subfloridana, U. fulvoreagens–U. glabrescens, U. barbata–U. chaetophora–U. dasopoga–U. diplotypus, U. barbata–U. intermedia–U. lapponica–U. substerilis). We propose synonymization of U. substerilis under U. lapponica. The status of several other species within intermixed clusters requires further evaluation with more extensive sampling and the inclusion of more variable markers before taxonomic consequences can be considered. A new species, Usnea parafloridana is described from Wisconsin, USA.
Received: 22 July 2015 / Accepted: 29 September 2015 / Published online: 10 October 2015
Acoelomorpha: earliest branching bilaterians or deuterostomes?Download PDFAbstract
The Acoelomorpha is an animal group comprised by nearly 400 species of misleadingly inconspicuous flatworms. Despite this, acoelomorphs have been at the centre of a heated debate about the origin of bilaterian animals for 150 years. The animal tree of life has undergone major changes during the last decades, thanks largely to the advent of molecular data together with the development of more rigorous phylogenetic methods. There is now a relatively robust backbone of the animal tree of life. However, some crucial nodes remain contentious, especially the node defining the root of Bilateria. Some studies situate Acoelomorpha (and Xenoturbellida) as the sister group of all other bilaterians, while other analyses group them within the deuterostomes which instead suggests that the last common bilaterian ancestor directly gave rise to deuterostomes and protostomes. The resolution of this node will have a profound impact on our understanding of animal/bilaterian evolution. In particular, if acoelomorphs are the sister group to Bilateria, it will point to a simple nature for the first bilaterian. Alternatively, if acoelomorphs are deuterostomes, this will imply that they are the result of secondary simplification. Here, we review the state of this question and provide potential ways to solve this long-standing issue. Specifically, we argue for the benefits of (1) obtaining additional genomic data from acoelomorphs, in particular from taxa with slower evolutionary rates; (2) the development of new tools to analyse the data; and (3) the use of metagenomics or metatranscriptomics data. We believe the combination of these three approaches will provide a definitive answer as to the position of the acoelomorphs in the animal tree of life.
Received: 17 September 2015 / Accepted: 22 December 2015 / Published online: 14 January 2016
Towards a sound definition of Skeneidae (Mollusca, Vetigastropoda): 3D interactive anatomy of the type species, Skenea serpuloides (Montagu, 1808) and comments on related taxaDownload PDFAbstract
The family Skeneidae, originally characterized by their minute size, lack of nacre and a rhipidoglossate radula, is an example of a polyphyletic assemblage. Most ‘skeneimorph’ species are based on the shell, sometimes the radula and rarely features of the external body. Data on internal anatomy are almost entirely lacking. In order to provide a complete anatomical data set with histological information, we applied serial semithin sectioning and 3D reconstructions to describe and visualize the anatomy of the type species of Skeneidae, Skenea serpuloides (Montagu, 1808). In addition, comparative data are provided for three other Skeneidae, Skenea profunda Friele, 1879; Dillwynella lignicola Marshall, 1988 and Dillwynella voightae Kunze, 2011 as well as for a tiny turbinid-like species, Lodderena minima (Tenison-Woods, 1887). We diagnose Skeneidae as trochoidean vetigastropods with combined epipodial sense organs (ESOs), neck lobes, eyes with a closed vesicle and the diagnostic propodial penis. Other features include simultaneous hermaphroditism with distinct testis/vas deferens and ovary/oviduct, a urogenital opening with the right kidney and a distinct seminal receptacle. Several features of Skeneidae are explained by dwarfing through progenesis, and accordingly, we interpret paedomorphosis of various characters. In contrast, L. minima has a true hermaphroditic gland, but lacks of propodial penis and a receptaculum. Also, molecular data support an exclusion of Lodderena from the Skeneidae.
Received: 16 July 2015 / Accepted: 22 October 2015 / Published online: 07 November 2015
The steps towards an inconspicuous vein fusion documented in Stenosmylinae forewings (Neuroptera: Osmylidae)Download PDFAbstract
Based on respective numbers of branches in fore- and hind wing, and on the morphology of fossil species, it has been assumed that a fusion of the posterior branch of the posterior media (MP2) with the anterior cubitus (CuA) was acquired convergently in fore- and hind wings in several families of Neuroptera (Insecta), including the Osmylidae. The corresponding topographic homology conjectures (THCs) had to assume inconspicuous vein fusion, but without intermediate condition being reported. Based on inter-specific, intra-specific and intra-individual variations observed in forewings of a selection of Stenosmylinae species (Osmylidae), we herein document a complete transformation series ranging from the condition ‘MP2 and CuA approximating’ to ‘MP2 and CuA fully fused, without distinct origin of MP2’, with intermediate conditions in which the origin of MP2 has a cross-vein-like appearance. The relevance of series of conspecific specimens to investigate problematic THCs is emphasized.
Received: 14 September 2015 / Accepted: 13 January 2016 / Published online: 26 January 2016
How our view of animal phylogeny was reshaped by molecular approaches: lessons learnedDownload PDFAbstract
In the late 1980s, researchers began applying molecular sequencing tools to questions of deep animal phylogeny. These advances in sequencing were accompanied with improvements in computation and phylogenetic methods, and served to significantly reshape our understanding of metazoan evolution. Prior to this time, researchers asserted phylogenetic hypotheses based on their experience with taxa and to some degree, their authority. Molecular phylogenetic tools provided discrete methods and objective characters for reconstructing phylogeny. Nonetheless, major changes to widely accepted views, such as animal phylogeny, take time to be accepted. Development and acceptance of our current understanding of animal evolution occurred in three main phases: initial hypotheses based on 18S data, confirmation with additional molecular markers, and continued refinement with phylogenomics. With the advent of ideas such as Lophotrochozoa and Ecdysozoa, flaws in the traditional view became apparent. We now understand that complex morphological and embryological features (e.g., segmentation, coelom formation, development of body cavities) are much more evolutionarily plastic than previously recognized. Here, I explore how the transition from the traditional to the modern phylogenetic understanding of animal phylogeny occurred and examine some implications of this change in understanding. As the field moves forward, the utility of morphological and embryological characters for reconstruction of deep animal phylogeny should be discouraged. Instead, these characters should be interpreted in the light of independent phylogeny.
Received: 18 January 2016 / Accepted: 16 May 2016 / Published online: 24 May 2016
Unresolved questions in genitalia coevolution: bridging taxonomy, speciation, and developmental geneticsDownload PDFAbstract
Systematists and geneticists study biological diversity, but they use different approaches that rarely intersect. A very common pattern that is of interest for both researchers is the rapid evolution of genitalia, a trait of significant taxonomic utility in several sexually reproducing animal clades. The idea that both male and female genitalia are species-specific and play a role in reproductive isolation has long been controversial but has recently gained a renewed interest by speciation and developmental geneticists. Here, I highlight six unresolved questions in genitalia coevolution and I argue that systematists, with their well training in comparative morphology, usage of large and geographically diverse collections, and ability to apply molecular genetics techniques, can make important contributions. Such an extension of systematics into the speciation and developmental genetics realms is a promising opportunity to expand “integrative taxonomy” comparisons between DNA and morphology into more explanatory relationships between the two sources of taxonomic data.
Received: 28 December 2015 / Accepted: 17 May 2016 / Published online: 27 May 2016
Does size matter for horny beetles? A geometric morphometric analysis of interspecific and intersexual size and shape variation in Colophon haughtoni Barnard, 1929, and C. kawaii Mizukami, 1997 (Coleoptera: Lucanidae)Download PDFAbstract
Colophon is an understudied, rare and endangered stag beetle genus with all species endemic to isolated mountain peaks in South Africa’s Western Cape. Geometric morphometrics was used to analyse intersexual and interspecific variation of size and shape in the mandibles, heads, pronota and elytra of two sympatric species: Colophon haughtoni and Colophon kawaii. All measured structures showed significant sexual dimorphism, which may result from male-male competition for females. Female mandibles were too small and featureless for analysis, but male Colophon beetles possess large, ornate mandibles for fighting. Males had significantly larger heads and pronota that demonstrated shape changes which may relate to resource diversion to the mandibles and their supporting structures. Females are indistinguishable across species, but males were accurately identified using mandibles, heads and pronota. Male C. kawaii were significantly larger than C. haughtoni for all structures. These results support the species status of C. kawaii, which is currently in doubt due to its hybridisation with C. haughtoni. We also demonstrate the value of geometric morphometrics as a tool which may aid Colophon conservation by providing biological and phylogenetic insights and enabling species identification.
Received: 10 June 2015 / Accepted: 02 September 2015 / Published online: 11 September 2015
First comprehensive multi-tissue transcriptome of Cherax quadricarinatus (Decapoda: Parastacidae) reveals unexpected diversity of endogenous cellulaseDownload PDFAbstract
The Australian freshwater crayfish species, Cherax quadricarinatus Von Martens, 1868, is an important commercial and invasive species that is also being increasingly used as a model organism to address important and interesting questions in crustacean biology. Through deep sequencing of the transcriptome of C. quadricarinatus from the hepatopancreas and four other tissues, we examine the evolution of endogenously transcribed cellulase genes and provide new insights into controversial issues regarding the nutritional biology of crayfishes. A cluster assembly approach yielded one of the highest quality transcriptome assemblies for a decapod crustacean to date. A total of 206,341,872 reads with an average read length of 80 bp were generated from sequencing the transcriptomes from the heart, kidney, hepatopancreas, nerve, and testis tissues. The assembled transcriptome contains a total of 44,525 transcripts. A total of 65 transcripts coding for carbohydrate-active enzymes (CAZy) were identified based on hidden Markov model (HMM), and a majority of them display high relative transcript abundance in the hepatopancreas tissue, supporting their role in nutrient digestion. Comprehensive phylogenetic analyses of proteins belonging to two main glycosyl hydrolase families (GH9 and GH5) suggest shared ancestry of C. quadricarinatus cellulases with other characterized crustacean cellulases. Our study significantly expands the number of known crustacean-derived CAZy-coding transcripts. More importantly, the surprising level of evolutionary diversification of these proteins in C. quadricarinatus suggests that these enzymes may have been of critical importance in the adaptation of freshwater crayfishes to new plant-based food sources as part of their successful invasion of freshwater systems from marine ancestors.
Received: 10 November 2015 / Accepted: 16 March 2016 / Published online: 04 April 2016
Variability on microevolutionary and macroevolutionary scales: a review on patterns of morphological variation in Cnidaria MedusozoaDownload PDFAbstract
Members of Cnidaria Medusozoa are known for their wide morphological variation, which is expressed on many different levels, especially in different phases of the life cycle. Difficulties in interpreting morphological variations have posed many taxonomic problems, since intraspecific morphological variations are often misinterpreted as interspecific variations and vice-versa, hampering species delimitation. This study reviews the patterns of morphological variation in the Medusozoa, to evaluate how different interpretations of the levels of variation may influence the understanding of the patterns of diversification in the group. Additionally, we provide an estimate of the cryptic diversity in the Hydrozoa, based on COI sequences deposited in GenBank. Morphological variations frequently overlap between microevolutionary and macroevolutionary scales, contributing to misinterpretations of the different levels of variation. In addition, most of the cryptic diversity described so far for the Medusozoa is a result of previously overlooked morphological differences, and there is still great potential for discovering cryptic lineages in the Hydrozoa. We provide evidence that the number of species in the Medusozoa is misestimated and emphasize the necessity of examining different levels of morphological variations when studying species boundaries, in order to avoid generalizations and misinterpretations of morphological characters.
Received: 29 June 2015 / Accepted: 19 November 2015 / Published online: 28 November 2015
Phylogeography of three closely related myrmecophytic pioneer tree species in SE Asia: implications for species delimitationDownload PDFAbstract
Members of the Euphorbiaceae are ecologically important elements of Southeast Asian forests. Species of the pioneer tree genus Macaranga, which is also known for its association with ants, are often abundant in disturbed areas. Phylogenetic studies suggested a recent radiation of section Pachystemon which comprises the majority of obligate myrmecophytes within Macaranga. In the present study, we analyzed the genetic structure of three closely related species of this section (M. constricta, M. griffithiana, and M. motleyana) with the aim of resolving their controversial taxonomy and historical biogeography. Chloroplast DNA haplotypes proved to be species-specific and showed a strong phylogeographic pattern. Nuclear microsatellite data supported the taxonomic distinctness of M. griffithiana and M. motleyana, but gave ambiguous results for M. constricta. Genetic differentiation was stronger each within M. griffithiana and M. motleyana than between M. constricta and M. griffithiana, highlighting problems of defining species boundaries. We found no indication for introgression or hybridization events. The high intraspecific morphological variation of the Bornean endemic M. motleyana was partly reflected by similar patterns of genetic variation. The pronounced genetic structure indicates a comparatively long diversification for this species. In contrast, the weak genetic differentiation within M. griffithiana, as well as the widespread distribution of its most common chloroplast haplotype from peninsular Malaysia up to Indochina, indicates a recent expansion in this area. Despite their morphological similarity and close relatedness, all species possess their own specific ant-partners with a corresponding distribution pattern.
Received: 18 May 2015 / Accepted: 22 December 2015 / Published online: 11 January 2016
Phylogeny and evolution of body mass in didelphid marsupials (Marsupialia: Didelphimorphia: Didelphidae)Download PDFAbstract
Most extant New World marsupials belong in the Didelphidae, which comprises ca. 110 currently recognized species of opossums. Didelphids are small mammals with their mean body mass, at species level, ranging from ca. 7 g to 2.2 kg. The largest species belong in a single clade, while substantial variation remains scattered across the remaining groups. We seek out to explore the details of this mass variation in an evolutionary framework. To this end, we first reconstructed the phylogeny of didelphids based on an extensive, although fragmentary sample of sequences from ten genes. We recovered a fully resolved, highly robust phylogeny that tested and confirmed most previously reported groupings, providing a simultaneous depiction of phylogenetic relationships for 81 % of currently recognized species and all relevant supra-specific clades. As much as 69 % of total body mass variation in didelphids was explained by this phylogenetic hypothesis. Mapped on it, mass variation evolved as much as 6.8 kg of total changes, starting from a reconstructed ancestral body mass range of 22–33 g. No single, family-wide pattern was evident; in fact, the dominant pattern for mass variation was that of increases in body mass along a few successive branches, or phyletic giantism, followed by apomorphic nanism, i.e., decreases localized in single terminal branches. Phyletic trends indicated the persistence of gradual, directional changes along considerable spans of geological time and show that substantial variation of interest resides in this and perhaps most groups of small mammals.
Received: 28 November 2015 / Accepted: 24 April 2016 / Published online: 10 May 2016
Towards resolving the double classification in Erythraeus (Actinotrichida: Erythraeidae): matching larvae with adults using 28S sequence data and experimental rearingDownload PDFAbstract
The taxonomy of free-living adults and heteromorphic parasitic larvae of Parasitengona mites has in the past been treated independently resulting in a double classification. Correct linkage of names still remains unknown for many species. A holistic understanding of species is imperative for understanding their role in ecosystems. This is particularly true for groups like parasitengone mites with a radically altered lifestyle during development—parasitic to predatory. Here, we infer linkages of three nominal species of Erythraeus, using matching with 28S DNA sequence data from field-collected specimens and through laboratory rearing. The general mixed Yule coalescent method (GMYC) was used to explicitly test if field-collected specimens representing heteromorphic life instars were conspecific. The field-collected larvae were allocated to adults of Erythraeus cinereus and Erythraeus regalis, respectively. Laboratory rearing of the same two species confirmed the matching done by DNA. Rearing was also successful for Erythraeus phalangoides after eggs were treated to an imitated winter diapause. This integrative taxonomic approach of molecular, morphological, and rearing data resulted in the following synonyms: E. phalangoides (De Geer, 1778) [= Erythraeus adrastus (Southcott, 1961), syn. nov.], E. cinereus (Dugès, 1834) [= Erythraeus jowitae Haitlinger, 1987, syn. nov.], and E. regalis (C.L. Koch, 1837) [= Erythraeus kuyperi (Oudemans, 1910), syn. nov., = Erythraeus gertrudae Haitlinger, 1987, syn. nov.]. The molecular evidence confirmed the separate identity of three further members of the genus. We provide redescriptions of E. phalangoides, E. cinereus, and E. regalis after modern standards, and neotypes are designated.
Received: 20 December 2015 / Accepted: 17 May 2016 / Published online: 27 May 2016
Testing heterogeneous base composition as potential cause for conflicting phylogenetic signal between mitochondrial and nuclear DNA in the land snail genus Theba Risso 1826 (Gastropoda: Stylommatophora: Helicoidea)Download PDFAbstract
Several pitfalls can mislead phylogenetic analyses based on molecular data, including heterogeneous base composition. Previous work has revealed conflicting topologies in analyses of the land snail genus Theba Risso 1826 based on mitochondrial cytochrome oxidase subunit I (COI) and nuclear AFLP data, respectively. However, the third codon positions of COI had heterogeneous base composition, prompting the present investigation asking specifically if this was the cause for the mito-nuclear discordance. For a potentially better resolution of the mitochondrial data, we also sequenced a fragment of 16S rRNA, the loop sections of which proved to have inhomogeneous base frequencies as well. In partitioned phylogenetic analyses, we compared topologies generated from the original data to those based on alignments in which the heterogeneous partitions were RY-coded and to a LogDet transformed distance analysis. In addition, we tested whether conventional Bayesian analyses would reconstruct the original topology from inhomogeneous data simulated based on this original topology. All our analyses, regardless of whether we accounted for heterogeneous base frequencies or not, revealed very similar topologies, confirming previous findings. Thus, the phylogenetic signal of mtDNA in the land snail genus Theba appeared to be robust despite considerable inhomogeneity of base composition. Therefore, the discordance of mitochondrial and nuclear topologies is probably real and most likely a consequence of incomplete lineage sorting.
Received: 28 January 2016 / Accepted: 11 May 2016 / Published online: 25 May 2016
Integrative analysis of the West African Ceraceosorus africanus sp. nov. provides insights into the diversity, biogeography, and evolution of the enigmatic Ceraceosorales (Fungi: Ustilaginomycotina)Download PDFAbstract
The order Ceraceosorales (Ustilaginomycotina) currently includes the single genus Ceraceosorus, with one species, Ceraceosorus bombacis, parasitic on Bombax ceiba in India. The diversity, biogeography, evolution, and phylogenetic relationships of this order are still relatively unknown. Here, a second species of Ceraceosorus is described from West Africa as a novel species, Ceraceosorus africanus, infecting Bombax costatum in Benin, Ghana, and Togo. This species produces conspicuous fructifications, similar to corticioid basidiomata when mature, but sorus-like in early stages of ontogenetic development. The fructifications cover much of the leaf surface and resemble leaf blight. This contrasts with the inconspicuous fructifications of C. bombacis comprising small spots scattered over the lower leaf surface that resemble leaf spot. Both species of Ceraceosorus differ in several micromorphological traits, infect different host plant species in widely separated geographical areas, and are separated by a considerable genetic distance in 28S rDNA and RPB2 genes. The distinct corticioid fructification of C. africanus is a unique morphological trait within the Ustilaginomycotina. Molecular phylogenetic analyses of a single gene dataset (D1/D2 28S rDNA) supported the monophyly of the two Ceraceosorus species and the Ceraceosorales and their placement within the Ustilaginomycotina. Molecular phylogenetic analyses of a multigene dataset (18S/5.8S/28S rDNA/RPB2/TEF1) revealed Exobasidium rhododendri (Exobasidiales) as the closest relative of Ceraceosorus, both clustering together with Entyloma calendulae (Entylomatales), indicating affinities to the Exobasidiomycetes. This phylogenetic placement is in agreement with ultrastructural characteristics (presence of local interaction zone and interaction apparatus) reported for the Ceraceosorales, Entylomatales, and Exobasidiales.
Received: 30 March 2016 / Accepted: 04 April 2016 / Published online: 01 August 2016
Multiple, solid evidence support that Austropotamobius italicus is not native to SpainDownload PDF
Received: 28 April 2015 / Accepted: 28 July 2015 / Published online: 28 August 2015
Comparative morphology and phylogenetic significance of Gregory’s diverticulum in sand dollars (Echinoidea: Clypeasteroida)Download PDFAbstract
Several derived sand dollar (Echinoidea: Clypeasteroida) families are characterized by the presence of Gregory’s diverticulum, an accessory organ of the digestive tract. This soft tissue structure is composed of a central tubular cecum that gives off multiple lobes into the periphery of the test. Most notable are the organ’s capacity to selectively store sand grains that the animal has taken up from the surrounding sediment as well as the gradual reduction of Gregory’s diverticulum during ontogeny. Several aspects of the biology of this structure have remained unexplored, including the organ’s precise morphology and structural diversity. In order to provide a concise basis for future histological, physiological, and functional analyses, a comprehensive comparative morphological and phylogenetic study across numerous taxa was undertaken. Taxon sampling comprised over 100 clypeasteroid species, including various fossil taxa. This extensive dataset permits establishing a concise terminology that incorporates all of the organ’s substructures. In addition, three-dimensional models of Gregory’s diverticulum are presented that provide an improved spatial understanding of the organ’s morphology in situ. The combined data from dissection, X-ray imaging, microcomputed tomography, and magnetic resonance imaging reveal a previously unknown variability of the structure, which also yields several phylogenetically informative morphological characters. Among those sand dollar families that possess Gregory’s diverticulum, the organ is present in two distinct shapes, which can be distinguished by the number, shape, and location of substructures. In addition, the data provide unequivocal evidence that Gregory’s diverticulum is absent in the extant taxa Rotulidae and Astriclypeidae, but also in the enigmatic Marginoproctus.
Received: 19 July 2015 / Accepted: 22 October 2015 / Published online: 03 November 2015
Molecular and morphological evidence for an intercontinental range of the liverwort Lejeunea pulchriflora (Marchantiophyta: Lejeuneaceae)Download PDFAbstract
Examination of type specimens and additional vouchers has revealed that the African Taxilejeunea pulchriflora and the tropical Asian Lejeunea propagulifera and Lejeunea tamaspocsii show considerable morphological overlap; however, morphological similarity does not necessarily indicate genetic similarity. Thus, sequences of two chloroplast regions (trnL-trnF, rbcL) and the nuclear ribosomal ITS region were generated from accessions of these taxa from Tanzania, Ethiopia, Thailand, Malaysia, and the Fiji Islands and integrated into an existing Lejeunea dataset. Phylogenetic analyses of the three-marker dataset resolved the three taxa in a robust monophyletic lineage and indicated relationships to Neotropical and Holarctic species. Based on the morphological similarities and the low molecular variation of the investigated accessions, we consider the three taxa as conspecific and propose two synonyms and a new combination, Lejeunea pulchriflora. Lejeunea pulchriflora is characterized by its asymmetrical leaf lobes, small, distant underleaves, toothed perianth keels, and autoicy and ranges from tropical Africa to the Pacific region.
Received: 15 February 2016 / Accepted: 27 April 2016 / Published online: 07 May 2016
A phylogeny of Cephaloziaceae (Jungermanniopsida) based on nuclear and chloroplast DNA markersDownload PDFAbstract
Cephaloziaceae represent a subcosmopolitan lineage of largely terrestrial leafy liverworts with three-keeled perianths, a reduced seta, capsules with bistratose walls, filamentous sporelings, large, thin-walled cells, and vegetative distribution by gemmae. Here we present the most comprehensively sampled phylogeny available to date based on the nuclear ribosomal internal transcribed spacer region and the chloroplast markers trnL-trnF and rbcL of 184 accessions representing 41 of the 89 currently accepted species and four of the five currently accepted subfamilies. Alobielloideae are placed sister to the remainder of Cephaloziaceae. Odontoschismatoideae form a sister relationship with a clade consisting of Schiffnerioideae and Cephalozioideae. Cephalozioideae are subdivided in three genera, Fuscocephaloziopsis, Cephalozia, and Nowellia, the last two in a robust sister relationship. Most morphological species circumscriptions are supported by the molecular topologies but the Cephalozia bicuspidata complex and the Cephalozia hamatiloba complex require further study. A Neotropical clade of Odontoschisma originates from temperate ancestors. Odontoschisma yunnanense is described as new to science.
Published online: 02 September 2016
Erratum to: Biogeography, cryptic diversity, and queen dimorphism evolution of the Neotropical ant genus Ectatomma Smith, 1858 (Formicidae, Ectatomminae)Download PDF
Received: 16 February 2015 / Accepted: 18 August 2015 / Published online: 02 September 2015
The application of “-omics” technologies for the classification and identification of animalsDownload PDFAbstract
The correct classification of organisms based on specific rules is essential in biological sciences. Traditionally, morphological characteristics such as size, shape, color, and anatomical structures have been used to identify and classify species. However, as consequence of the tremendous advances in molecular technologies during the last years, new approaches have become available for taxonomic research. Various modern high-throughput technologies allow the detailed characterization of the genome, proteome, metabolome as well as the morphology of an organism. Furthermore, the open access storage of such comprehensive data sets as part of an uprising digital cybertaxonomy enables highly fascinating digital dimensions for modern taxonomy, including the buildup of virtual collections as well as data sets for 3D printing techniques that can be used to replicate complete voucher specimens or at least important diagnostic characters. As a result of these advances, we are now able to document, describe, and identify species much more comprehensively than just a few years ago. In this review we provide an overview about the technical advances in taxonomic research in recent years and discuss their power and limitations.
Received: 19 May 2015 / Accepted: 19 November 2015 / Published online: 16 December 2015
Phylogenetic relationships of Isospora, Lankesterella, and Caryospora species (Apicomplexa: Eimeriidae) infecting lizardsDownload PDFAbstract
In this study, several species of Isospora infecting lizards were genetically characterized. Specifically, five described and four newly described species of Isospora were included in a phylogeny of the family Eimeriidae. These species were isolated from hosts originally inhabiting all geographic continents except Europe. Phylogenetic analyses of the 18S ribosomal RNA (rRNA) gene grouped these nine species of Isospora with Lankesterella species and Caryospora ernsti. Therefore, within this clade, different evolutionary strategies in oocyst development and transmission occurred. Although the characteristic endogenous oocyst development of the genus Lankesterella may have arisen only once, the reduction in the number of sporocysts observed in the genus Caryospora occurred at least twice during coccidian evolution, as evidenced by the phylogenetic position of Caryospora bigenetica as the sister taxon of the group formed by reptilian Isospora, Lankesterella, and C. ernsti. Within this group, C. ernsti was the sister taxon to the genus Lankesterella. Overall, our results contradict the proposed monophyly of the genus Caryospora, highlighting the need for a thorough taxonomic and systematic revision of the group. Furthermore, they suggest that the recent ancestor of the genus Lankesterella may have been heteroxenous.
Received: 23 October 2015 / Accepted: 27 March 2016 / Published online: 04 April 2016
Evolution of hyperflexible joints in sticky prey capture appendages of harvestmen (Arachnida, Opiliones)Download PDFAbstract
The rigid leg segments of arthropods are flexibly connected by joints, which usually consist of two ball-and-bowl hinges, permitting a uniaxial pivoting up to 140°. Here, we report the occurrence of hyperflexible joints (range of movements = 160–200°) in the pedipalps (second pair of appendages) of some harvestmen (Sabaconidae and Nemastomatidae), representing some of the most flexible leg joints among arthropods. Hyperflexion is achieved by a reduction of hinges and a strong constriction of the joint region. We demonstrate that hyperflexion occurs during prey capture and is used to clamp appendages of the prey, in addition to attachment by glue secreted by specialized setae. By means of high-speed video recordings, we found that in the Sabaconidae the tibiotarsal joint of the pedipalp can flex extremely rapidly (<5 ms), limiting prey escape. This is the fastest reported predatory strike in arachnids and caused both by leverage and a click mechanism. By comparative analysis of different related taxa, we retraced joint evolution and found that hyperflexion has independently evolved in Sabaconidae and Nemastomatidae, with totally different joint kinematics. We hypothesize that (rapid) hyperflexion evolved to enhance the efficiency of the pedipalp as a means of prey capture, because in springtails detachable scales limit the action of the sticky secretion of pedipalpal setae.
Received: 23 June 2015 / Accepted: 15 November 2015 / Published online: 25 November 2015
Distributional modeling of Mantophasmatodea (Insecta: Notoptera): a preliminary application and the need for future samplingDownload PDFAbstract
Insects are the most diverse animal group, with remarkable and critical ecological roles, but the understanding of the taxonomic diversity, distribution, and biology of the overwhelming majority of lineages remains in its incipient stages. One means of addressing the lack of reliable distributional data for many groups is to predict probable records using species distribution models (SDMs), and this is particularly useful for generally undersampled and rarely encountered groups. Here, we use existing distribution records for species and genera of Mantophasmatodea (Insecta: Notoptera) to generate SDMs and discuss their utility for future sampling efforts. We used two different algorithms (Envelope Score and MaxEnt) to generate potential distributions and indicate areas for future field surveys for some of the genera and species of Mantophasmatodea with at least 10 unique occurrence records. The models showed good predictive capability (true skill statistics >0.9), with different taxa exhibiting variables, endemic ranges largely in southern and southwestern Africa, areas under considerable risk from climate change. South and Southwest Africa are the best places to focus sampling efforts for empirical data on current occurrences and any possible future shifts, as well as the potential for discovery of previously unknown species. These results also highlight the need to study the smaller and lesser known lineages of invertebrates that may not represent charismatic target taxa but nonetheless harbor unique life histories with unknown ecological roles.
Received: 21 October 2015 / Accepted: 03 January 2016 / Published online: 19 January 2016
Who lives where? Molecular and morphometric analyses clarify which Unio species (Unionida, Mollusca) inhabit the southwestern PalearcticDownload PDFAbstract
Many doubts still exist about which freshwater mussel Unio species inhabit Northwest Africa. While some authors refer to the presence of Unio delphinus in the Atlantic North African basins of Morocco, a recent International Union for Conservation of Nature (IUCN) assessment performed on Moroccan Unio species, recognised the existence of a distinct species, Unio foucauldianus, with a critically endangered conservation status. The present study delivered new genetic, morphological, and geographical distribution data on two Unio species (i.e. U. delphinus and U. foucauldianus) greatly increasing the almost non-existent data on these taxa. Bayesian phylogenetic analysis revealed two highly supported geographically concordant clades, which diverged by 3.2 ± 0.6 % (uncorrected p distance): the first distributed across Iberia and corresponding to U. delphinus, and the second distributed across Morocco, corresponding to U. foucauldianus. These results were corroborated by the analysis of ten newly developed microsatellite loci as well as shell morphometry. We suggest that the IUCN critically endangered conservation status of U. foucauldianus should be revised and probably down-listed since its actual distribution is much wider than previously described. Phylogenetic relationships with the other Unio species were resolved, showing that U. delphinus and U. foucauldianus fall inside the pictorum lineage. The estimated molecular rate reported herein (0.265 ± 0.06 % per million years) represents the first for the Unionida and could be used as a reference in future studies.
Received: 07 July 2015 / Accepted: 11 November 2015 / Published online: 28 November 2015
The plastic nervous system of NemertodermatidaDownload PDFAbstract
Nemertodermatida are microscopic marine worms likely to be the sister group to acoels, forming with them the earliest extant branch of bilaterian animals, although their phylogenetic position is debated. The nervous system of Flagellophora cf. apelti, Sterreria spp. and Nemertoderma cf. westbladi has been investigated by immunohistochemistry and confocal microscopy using anti-tubulin, anti-5-HT and anti-FMRFamide antibodies. The nervous system of F. cf. apelti is composed of a large neuropile and a loose brain at the level of the statocysts with several nerve fibres surrounding them and innervating the broom organ. Sterreria spp. shows a commissural-like brain and several neurite bundles going frontad and caudad from this. At the level of the statocysts there is also a thicker aggregation of immunoreactive fibres. The nervous system of N. cf. westbladi consists of a nerve ring lying outside the body wall musculature at the level of the statocyst and a pair of ventro-lateral neurite bundles, from which extend thinner fibres innervating the ventral side of the animal. Numerous bottle-shaped glands were observed, innervated by fibres starting both from the brain and the neurite bundles. The nervous system of the nemertodermatids studied to date displays no common pattern; instead, there is considerable plasticity in the general morphology of the nervous system. In addition, the musculature of Sterreria spp. has been studied by phalloidin staining. It shows diagonal muscles in the anterior quarter of the body and a simple orthogonal grid in the posterior three quarters, being simpler than that of the other nemertodermatids. High-resolution differential interference contrast microscopy permitted to better visualize some morphological characters of the species studied, such as statocysts, sperm and glands and, in combination with anti-tubulin staining, describe in detail the broom organ in F. cf. apelti. Finally, we note an apparent absence of innervation of the gut in Nemertodermatida similar to the condition in Xenoturbella.
Received: 28 October 2015 / Accepted: 19 January 2016 / Published online: 02 February 2016
The female reproductive tract of Grallipeza sp. A (Diptera: Micropezidae)—large ventral receptacle substitutes for spermathecae convergently in small and widely separated dipteran cladesDownload PDFAbstract
The internal female reproductive tract of a Neotropical species of stilt-legged fly (Diptera: Micropezidae: Grallipeza sp. A) is described and illustrated with microphotography. Special emphasis is given to the massively enlarged sclerotized tubular ventral receptacle and an almost complete reduction of the spermathecal capsules, suggesting that sperm storage has been shifted from the spermathecae to the ventral receptacle. This constitutes a remarkable convergence with analogous developments in other dipteran taxa. The published information on the internal female reproductive tract of other Micropezidae is reviewed, and the evolutionary history of the condition in Grallipeza sp. A is reconstructed and related to evolutionary processes likely involving sperm competition and cryptic female choice. The presence of paired accessory glands in Grallipeza sp. A is confirmed.
Received: 23 March 2015 / Accepted: 30 November 2015 / Published online: 21 December 2015
Resurrection of the Comoran fish scale gecko Geckolepis humbloti Vaillant, 1887 reveals a disjunct distribution caused by natural overseas dispersalDownload PDFAbstract
Fish scale geckos (Geckolepis) are taxonomically poorly resolved, mainly because of the difficulty of applying standard morphological characters to diagnose taxa. Three species, Geckolepis maculata, G. polylepis, and G. typica, are currently recognized from Madagascar and the Comoro Islands. Molecular studies suggested a number of operational taxonomical units within the G. maculata complex, but none of these has been formally described. The Comoran population was described as Geckolepis humbloti Vaillant 1887 but later synonymized. Prior to our study, no genetic data and little other information were available for this taxon. We revised the status of G. humbloti using molecular genetics, external morphology, and osteological characters retrieved from 3D skeletal models created using micro-computed tomography (micro-CT). Our results demonstrate that G. humbloti represents a genetic lineage strongly distinct from all other Geckolepis species. It is furthermore distinguished by a combination of external morphological characters and probably by osteology. We therefore resurrect G. humbloti Vaillant, 1887 from synonymy with G. maculata. Remarkably, this lineage is not restricted to the Comoros: A specimen from Tsingy de Bemaraha in western Madagascar falls as a closely related sister lineage to all Comoran Geckolepis in our molecular phylogenetic analysis and is osteologically almost identical with a specimen from the type locality Grand Comoro. We therefore include it in G. humbloti. The phylogenetic topology and the intraspecific genetic divergences suggest that the Comoros were colonized naturally from western Madagascar by overseas dispersal. G. humbloti is not considered as threatened, but its presence is indicative of natural or near-natural habitats.
Received: 03 October 2015 / Accepted: 14 December 2015 / Published online: 11 January 2016
A phylogeny of Lophocoleaceae-Plagiochilaceae-Brevianthaceae and a revised classification of PlagiochilaceaeDownload PDFAbstract
The Lophocoleaceae-Plagiochilaceae-Brevianthaceae clade is a largely terrestrial, subcosmopolitan lineage of jungermannialean leafy liverworts that may include significantly more than 1000 species. Here we present the most comprehensively sampled phylogeny available to date based on the nuclear ribosomal internal transcribed spacer region and the chloroplast markers rbcL and rps4 of 372 accessions. Brevianthaceae (consisting of Brevianthus and Tetracymbaliella) form a sister relationship with Lophocoleaceae; this lineage is in turn sister to Plagiochilaceae. Plagiochila is resolved monophyletic subsequent to exclusion of Plagiochila radiculosa; this species is placed in a new genus Cryptoplagiochila. Chiastocaulon and a polyphyletic Acrochila nest in Plagiochilion; these three genera are united under Chiastocaulon to include the Plagiochilaceae species with dominating or exclusively ventral branching. The generic classification of the Lophocoleaceae is still unresolved. We discuss alternative approaches to obtain strictly monophyletic genera by visualizing their consistence with the obtained consensus topology. The presented phylogeny will serve as a basis for follow-up studies including several thousand accessions. These studies will enable revision of current hypotheses on species diversity and distribution of Lophocoleaceae-Plagiochilaceae-Brevianthaceae and allow for a reconstruction of their evolution in time and space.
Received: 03 November 2015 / Accepted: 25 January 2016 / Published online: 05 February 2016
The phylogeny, evolutionary developmental biology, and paleobiology of the Deuterostomia: 25 years of new techniques, new discoveries, and new ideasDownload PDFAbstract
Over the past 25 years, new techniques, new discoveries, and new ideas have profoundly impacted our understanding of deuterostome interrelationships and, ultimately, deuterostome evolution. During the late 1980s and early 1990s morphological cladistic analyses made predictions about both taxonomic history and homology, predictions that would be tested independent of the morphological characters themselves with the advent of molecular systematics, the rise of evolutionary developmental biology, and continued exploration of the fossil record. Thanks to these three areas of inquiry, we have gone from scenarios where animals like mobile enteropneust hemichordates and chordates were derived from sessile filter-feeding animals like modern lophophorates, echinoderms, and pterobranch hemichordates, to a new perspective where hemichordates are recognized as the nearest living relative of the echinoderms, and that vagile gill-bearing animals like Cambrian vetulicolians are seen—at least by some—as close to the deuterostome last common ancestor, with both sessility and filter-feeding convergent features of deuterostomes (e.g., echinoderm) and non-deuterostomes (e.g., lophophorates) alike. Although much of the backbone of the new deuterostome phylogeny is supported by multiple independent data sets, as are statements of homology of several different morphological characters, in particular the homology of gill slits across Deuterostomia, nonetheless, the next quarter century of study on this remarkable group of animals promises to be as equally illuminating and exciting as the past quarter century.
Received: 31 July 2015 / Accepted: 03 November 2015 / Published online: 11 November 2015
Hybosorus ocampoi: the first hybosorid from the Cretaceous Myanmar amber (Coleoptera: Scarabaeoidea)Download PDFAbstract
The Hybosoridae is a cosmopolitan family of Scarabaeoidea that is most diverse in the tropics. Up to now, all published Mesozoic hybosorids were compression fossils, except for one from Lebanon amber which is incomplete. A new species, Hybosorus ocampoi Bai et Zhang sp. nov., of Hybosoridae (Scarabaeoidea) is described and illustrated based on one well-preserved Myanmar amber specimen. The phylogenetic position of H. ocampoi was analyzed by employing 117 morphological characters and 44 extant/extinct species. The documented features are discussed and analyzed with respect to the phylogenetic placement of the species which may have a strong impact on the evolution in Hybosoridae and greatly expand our knowledge on the early evolution of Scarabaeoidea. Our finding provides solid evidence to prove the very old origin of the genus Hybosorus which is the type genus of Hybosoridae. Furthermore, this finding not only supports the hypothesis of Mesozoic origin of most families in Scarabaeoidea but also supports some genera of Scarabaeoidea might have already appeared in the Mesozoic. The palaeobiogeography of Hybosoridae and its palaeoenvironmental implications are also discussed.
Received: 07 May 2015 / Accepted: 10 January 2016 / Published online: 20 January 2016
The meaning of categorical ranks in evolutionary biologyDownload PDFAbstract
Despite having been utilized for over 250 years, Linnaean ranks are periodically dismissed by some systematists and evolutionary biologists. Here, we discuss recent criticisms and point out that they are often the result of a misunderstanding of both the meaning and the intent of such ranks. Although arbitrary in some cases, ranks contain meaningful taxonomic information, facilitate communication, and serve as proxies for a fully resolved and correctly dated tree of life. Ranks favor communication and evolutionary comparisons, but they do not make assumptions about equal age or diversity for any two taxa with the same Linnaean category.
Received: 06 January 2015 / Accepted: 22 September 2015 / Published online: 12 October 2015
Functional morphology of the cave bear (Ursus spelaeus) mandible: a 3D geometric morphometric analysisDownload PDFAbstract
The diet of the fossil cave bears (Ursus spelaeus group) has been debated extensively. Thought traditionally to be herbivorous, more recent studies have proposed more meat in the cave bear diet. To test this, the mandibular morphology of cave bears was analysed using 3D geometric morphometrics and compared to that of extant Ursidae. Landmarks for 3D digitisation of the mandible were chosen to reflect functional morphology relating to the temporalis and masseter muscles. Extant and extinct Pleistocene Ursidae were digitised with a MicroScribe G2. Generalised Procrustes superimposition was performed, and data were allometrically and phylogenetically corrected. Principal component analysis (PCA), two-block partial least squares analysis (2B-PLS), regression analysis and discriminant function analysis were performed. PCA and 2B-PLS differentiate between known dietary niches in extant Ursidae. The lineage of the cave bear runs parallel to that of the panda (Ailuropoda melanoleuca) in morphospace, implying the development of morphological adaptations for eating foliage. A regression of shape onto foliage content in the diet and a discriminant function analysis also indicate that the cave bear diet consisted primarily of foliage.
Received: 24 May 2015 / Accepted: 15 November 2015 / Published online: 01 December 2015
The homology of cephalic muscles and endoskeletal elements between Diplura and Ectognatha (Insecta)Download PDFAbstract
Diplura (two-pronged bristletails) are key to our understanding of hexapod head evolution. A sister group relationship with Ectognatha (=Insecta), comprising bristletails, silverfish and winged insects, is advocated in most modern studies, however, homologization of head muscles and endoskeletal elements between Diplura and Ectognatha is still lacking. Here, we present the first homologization of a number of head muscles and endoskeletal structures between Diplura and Ectognatha. A homologization of these structures is possible if a range of species, both from Japygidae and Campodeidae, are studied in order to reconstruct the potential groundplan characteristics and account for inner anatomy variations within Diplura. Japygidae and Campodeidae show differences in the origin, insertion, and presence of mandibular and maxillary muscles as well as the shape of the maxillary cardo. Taking into account recent embryological studies on the formation of the endoskeleton in Protura, Collembola and Diplura, we furthermore reconstruct the potential evolution of the endoskeleton in early Hexapoda. The tentorium is a defining feature of dicondylic insects (including Archaeognatha) while anterior and posterior cephalic invaginations (the later tentorial pits of dicondylic insects) are groundplan features of Hexapoda. Additionally, we clarify the composition of the gnathal pouches (i.e. the type of entognathy) in Diplura and Collembola. The pouches in Diplura are posteriorly separated, similar to the state encountered in Collembola. This contrasts to former studies emphasizing the differences in the ellipuran and dipluran type of entognathy.
Received: 15 July 2015 / Accepted: 27 December 2015 / Published online: 16 January 2016
On 20 years of LophotrochozoaDownload PDFAbstract
Lophotrochozoa is a protostome clade that includes disparate animals such as molluscs, annelids, bryozoans, and flatworms, giving it the distinction of including the most body plans of any of the three major clades of Bilateria. This extreme morphological disparity has prompted numerous conflicting phylogenetic hypotheses about relationships among lophotrochozoan phyla. Here, I review the current understanding of lophotrochozoan phylogeny with emphasis on recent insights gained through approaches taking advantage of high-throughput DNA sequencing (phylogenomics). Of significance, Platyzoa, a hypothesized clade of mostly small-bodied animals, appears to be an artifact of long-branch attraction. Recent studies recovered Gnathifera (Syndermata, Gnathostomulida, and Micrognathozoa) sister to all other lophotrochozoans and a clade called Rouphozoa (Platyhelminthes and Gastrotricha) sister to the remaining non-gnathiferan lophotrochozoans. Although Bryozoa was traditionally grouped with Brachiopoda and Phoronida (Lophophorata), most molecular studies have supported a clade including Entoprocta, Cycliophora, and Bryozoa (Polyzoa). However, recent phylogenomic work has shown that entoprocts and bryozoans have compositionally heterogeneous genomes that may cause systematic artifacts affecting their phylogenetic placement. Lastly, relationships within Trochozoa (Mollusca, Annelida, and relatives) largely remain ambiguous. Recent work has shown that phylogenomic studies must identify and reduce sources of systematic error, such as amino acid compositional heterogeneity and long-branch attraction. Still, other approaches such as the analysis of rare genomic changes may be needed to overcome challenges to standard phylogenomic approaches. Resolving lophotrochozoan phylogeny will provide important insight into how these complex and diverse body plans evolved and provide a much-needed framework for comparative studies.
Received: 28 December 2015 / Accepted: 11 April 2016 / Published online: 22 April 2016
Species radiation in the Alps: multiple range shifts caused diversification in Ringlet butterflies in the European high mountainsDownload PDFAbstract
The distributions of European high mountain species are often characterised by small and geographically isolated populations and, in many cases, have highly complex biogeographic histories. The butterfly genus Erebia represents one of the best examples for small-scale diversification in the European high mountain systems and therefore to understand speciation processes and associated range dynamics of high mountain species. In this study, we analysed 17 polymorphic allozyme loci of 1731 individuals from 49 populations representing four species, one of which has three subspecies: Erebia nivalis; Erebia tyndarus; Erebia ottomana; and Erebia cassioides cassioides, Erebia cassioides arvernensis, and Erebia cassioides neleus. Samples were collected in the high mountain systems of Europe (i.e. Pyrenees, Massif Central, Alps, Apennines, Carpathians, Balkan high mountains). Genetic analyses supported all previously accepted species. However, the genetic differentiation within E. cassioides sensu lato into three geographically delimited groups is justifying species rank: E. arvernensis distributed in the Pyrenees, Massif Central and western Alps; E. cassioides sensu stricto in the eastern Alps and Apennines; and E. neleus in the Balkan mountains and the south-western Carpathians. While the differentiation between western Alps and Massif Central as well as eastern Alps and Apennines was low, the Pyrenees as well as the south-western Carpathians were significantly differentiated from the other regions within the respective taxon. In general, the differentiation among the populations of E. neleus was stronger than between populations of the other taxa. Within E. cassioides, we found a west-east gradient of genetic similarity over the eastern Alps. Based on the obtained genetic structures, we are able to delineate glacial refugia and interglacial range modifications. Based on the genetic structures and genetic diversity patterns, we conclude that, triggered by the glacial-interglacial cycles, repeated range modifications have taken place with subsequent differentiation and speciation in the region of the Alps and Balkans. Colonisations to Pyrenees (E. arvernensis pseudomurina, E. arvernensis pseudocarmenta), Massif Central (E. ottomana tardenota, E. a. arvernensis) and Apennines (E. cassioides majellana) appear to be recent and most probably not older than the last interglacial period.
Received: 19 October 2015 / Accepted: 12 November 2015 / Published online: 10 December 2015
Review of data for a morphological look on Xenacoelomorpha (Bilateria incertae sedis)Download PDFAbstract
Recent investigations by means of high-tech morphology, evo-devo studies and molecular data suggest that the taxon Xenacoelomorpha (Nemertodermatida and Acoela plus Xenoturbella), formerly considered as primitive flatworms (Plathelminthes) or even bivalve Mollusca, represents either a quite plesiomorphic grouping as the earliest bilaterian offshoot or but is a substantially reduced and simplified sidebranch of ambulacralian Deuterostomia. Herein, I provide a compilation and review of the current morphological data and possible interpretations of the various character states. Phenotypic and genotypic data suggest monophyly of Xenacoelomorpha. There is no specific similarity between xenacoelmorphs and deuerostome larvae, and reduction appears improbable in free-living and predatory animals. Accordingly, Xenacoelomorpha are more likely similar to Urbilateria rather than degenerated and simplified coelomate deuterostomes. If so, the ground pattern of Bilateria has been retained only partially in the remaining main bilaterian clades (Nephrozoa) after the deviation of the Xenacoelomorpha, namely the nervous system in the Deuterostomia and the body cavity conditions in the acoelomate Lophotrochozoa (particularly Platyzoa), Gastrotricha and cycloneuralian Ecdysozoa.
Received: 15 September 2015 / Accepted: 04 March 2016 / Published online: 15 March 2016
Examining the sensitivity of molecular species delimitations to the choice of mitochondrial markerDownload PDFAbstract
Defining and understanding species diversity forms the basis of a wide range of biological and conservation work. Traditional taxonomy can be complemented and accelerated using molecular methods of species delimitation, such as the widely used Generalised Mixed Yule-Coalescent (GMYC) approach. This method uses time-calibrated phylogenetic trees in order to identify transition points between inter- and intraspecific divergence processes. Despite some important limitations, the GMYC approach appears to be robust to a wide range of dataset characteristics. It is one of the few model-based species-delimitation methods that remain practical for analysing molecular datasets with a large numbers of taxa. Most GMYC analyses have been based on datasets consisting of one or a small number of mitochondrial genes. To investigate the sensitivity of GMYC to the choice of mitochondrial marker, we compared GMYC estimates from 15 mitochondrial genes for three vertebrate datasets (cetaceans, ursids and whitefish). Despite the shared evolutionary history among mitochondrial genes, different markers exhibited substantial variation in GMYC delimitation results across all three datasets. This variability was not restricted to specific genes or taxa and extended to commonly used barcoding genes such as COI and CYTB. Using multiple concatenated markers mitigated these problems in two of the datasets, but exacerbated systematic biases present in a third. Our findings indicate the need to consider multiple markers, loci and lines of evidence when performing molecular species delimitation.
Received: 27 August 2015 / Accepted: 16 January 2016 / Published online: 30 January 2016
Current status of annelid phylogenyDownload PDFAbstract
Annelida is an ecologically and morphologically diverse phylum within the Lophotrochozoa whose members occupy a wide range of environments and show diverse life styles. The phylogeny of this group comprising more than 17,000 species remained controversial for a long time. By using next-generation sequencing and phylogenomic analyses of huge data matrices, it was finally possible to reach a well-supported and resolved annelid backbone tree. Most annelid diversity is comprised in two reciprocal monophyletic groups, Sedentaria and Errantia, which are named after the predominant life style of their members. Errantia include Aciculata (Phyllodocida + Eunicida) and Protodriliformia, which is a taxon of interstitial polychaetes. Sedentaria comprise most of the polychaete families formerly classified as Canalipalpata or Scolecida, as well as the Clitellata. Six taxa branch as a basal grade outside of this major radiation: Oweniidae, Magelonidae, Chaetopteridae, Sipuncula, Amphinomida, and Lobatocerebrum. Oweniidae and Magelonidae form a monophyletic group which we name Palaeoannelida, which constitutes the sister taxon of the remaining annelids. The early splits of annelid phylogeny date back to the Cambrian. The new annelid phylogeny highlights the variability and lability of annelid body plans, and many instances of simplifications of body plan as adaptations to new life styles can be found. Therefore, annelids will be an appropriate model to understand major transitions in the evolution of Bilateria in general. Evolutionary developmental studies are one way to investigate macroevolutionary transition in annelids. We briefly summarize the state of developmental model organisms in Annelida and also propose new candidates on the background of the phylogeny.
Received: 28 October 2015 / Accepted: 16 January 2016 / Published online: 02 February 2016
Lost in a taxonomic Bermuda Triangle: comparative 3D-microanatomy of cryptic mesopsammic Solenogastres (Mollusca)Download PDFAbstract
Solenogastres (Mollusca) have a quite uniform bodyplan and an evolutionary history with few shifts out of their deep-water habitat and beyond their epibenthic lifestyle. Consequently, few clades inhabit the shallow subtidal mesopsammon; only Meiomeniidae (order Pholidoskepia) is entirely restricted to this habitat. What was initially designed as a comparative microanatomical redescription of Meiomeniidae to explore the diversity of this clade with its unique evolution, developed into a taxonomic nightmare of cryptic, co-occurring lineages: three out of four valid species of Meiomeniidae co-occur in coarse sands in the Bermuda archipelago and were re-collected at the respective type localities. We analyzed the material combining three-dimensional (3D) reconstructions from histological serial sections and ultrastructural data, providing novel insights into meiomeniid anatomy and discussing potential phylogenetic implications. However, not all collected material could be unambiguously assigned to known lineages of mesopsammic Solenogastres. In addition to meiomeniids, we discovered another co-occurring, externally highly cryptic but anatomically distinguishable lineage. It is provisionally placed within Dondersiidae, but its taxonomic assignment remains problematic due to an exclusive character mosaic and a unique foregut gland complex. Our study reveals the risk of creating chimeric taxa in small-bodied Solenogastres, as morphological characters needed for species delineation cannot be extracted from single individuals, while conspecifity based on external features is risky to assume with cryptic species co-occurring. Molecular markers will be needed to reliably retrieve Meiomeniidae from their current Bermuda Triangle of taxonomy and to proceed in solenogaster taxonomy confronted with a wealth of poorly known lineages especially in meiofaunal forms.
Received: 20 December 2015 / Accepted: 11 April 2016 / Published online: 23 April 2016
Genetic structure of Parnassius mnemosyne (Lepidoptera: Papilionidae) populations in the Carpathian BasinDownload PDFAbstract
The pattern of genetic variation in a butterfly species depends on the past history of the given species and also on recent evolutionary processes affecting its populations. The aim of the present study was (i) to analyse the enzyme polymorphism in the Clouded Apollo populations of the Carpathian Basin to reveal the contemporary pattern of their genetic differentiation and (ii) to compare it with an expanded mitochondrial DNA (mtDNA) haplotype network of the SE European populations. Allozyme polymorphism was analysed in 22 populations of four geographic regions: Transdanubian (TM) and North Hungarian Mountains (NM), Körös (KÖR) and Bereg–Apuseni–East Carpathian regions (BEAC). The results of the Bayesian clustering analyses based on allozymes supported the presence of three main genetic lineages in the Carpathian Basin: One was typical for TM, another was characteristic for NM and the third cluster was predominant in KÖR. The populations of BEAC harboured a mixture of two clusters. The mtDNA haplotype network suggested a fairly similar distribution: The peri-Alpine clade together with the West Balkan clade was detected in TM, while the East Balkan clade occurred in NM, partly in TR and in the two eastern regions of the Basin (KÖR and BAEC). The incongruities between the results of the mtDNA and allozyme studies can be explained by the different timescales represented by the two markers. The mtDNA haplotype network provided strong evidence concerning the existence of two Balkan lineages, which probably formed a ‘zone of admixture’ in the Transdanubian and North Hungarian Mountains. The possibility of Last Glacial survival of Parnassius mnemosyne in the Carpathian Basin and the conservation implications of these results are discussed.
Received: 09 August 2015 / Accepted: 11 November 2015 / Published online: 25 November 2015
A short LSU rRNA fragment as a standard marker for integrative taxonomy in calcareous sponges (Porifera: Calcarea)Download PDFAbstract
Calcareous sponges are taxonomically difficult, and their morpho-systematic classification often conflicts with molecular phylogenies. Consequently, species descriptions that rely solely on morphological characters,and taxonomic revisions appear to provide little to no information about phylogenetic affiliations and integrative approaches, combining DNA and morphological data, are applied more frequently. However, a standardized database that combines DNA sequence and morphological specimen information is still missing for calcareous sponges. The mitochondrial cytochrome oxidase subunit 1 gene (COI) is the marker of choice for rapid species identification in many other animal taxa, including demosponges, for which COI sequences and morphological information have been compiled in the sponge barcoding database (
). But due to the peculiarities of calcarean mitochondrial genomes, sequencing COI in Calcarea is methodologically challenging. We here propose the use of one more commonly used DNA marker, the C-region of the 28S gene (LSU), as standard barcoding marker for Calcarea, after also considering the internal transcribed spacer (ITS) region for such proposes. Especially in the subclass Calcaronea, we observed severe problems of high intra- and intergenomic variation that impedes pan-calcarean ITS alignments. In contrast, the C-region of LSU provides a short but phylogenetically informative DNA sequence, alignable across both subclasses with the help of a newly developed secondary structure and which also can be used to address exemplary taxonomic questions. With our work, we start to close the gap of Calcarea in the sponge barcoding project (
) and provide a resource for biodiversity studies and potentially for DNA-guided species identification.
Received: 25 March 2015 / Accepted: 11 August 2015 / Published online: 07 September 2015
Phylogeography of the harvestman genus Metasiro (Arthropoda, Arachnida, Opiliones) reveals a potential solution to the Pangean paradoxDownload PDFAbstract
At both global and local scales, mite harvestmen (Opiliones, Cyphophthalmi) have been shown to have achieved their current global distribution strictly through vicariance. However, the implicit low dispersal capability of this group does not explain how they expand their ranges and come to occupy enormous landmasses prior to rifting. To investigate at the population level the limited vagility that characterizes the suborder generally, and how its dispersal capacity determines diversification dynamics, range expansion, and historical biogeography, we examined as a test case the phylogeography of the genus Metasiro. This genus consists of three widely separated, morphologically cryptic species that inhabit the Southeastern United States. Distances between sampling sites spanned a range of geographic scales, from 4 m to over 500 km. Population structure was inferred from fragments of six loci (three mitochondrial, three nuclear) amplified from 221 specimens. We tested for population structure and gene flow, constructed a dated phylogeny of the genus, and developed a program for estimating the effective population size with confidence intervals. Individuals of Metasiro americanus demonstrate remarkable population structure at scales of less than 25 m, but populations vary in their haplotypic diversity, and some exhibit evidence of historical gene flow. The estimated timing of cladogenesis within the genus accords closely with the geological history of the North American coastline, and the three species are at the endpoints of large watersheds. This suggests that mite harvestman lineages expand their ranges by hydrochory, providing for the first time a plausible mechanism whereby these animals dispersed across Pangea despite their low vagility in stable environments.
Received: 21 August 2015 / Accepted: 30 November 2015 / Published online: 15 December 2015
Chaetal type diversity increases during evolution of Eunicida (Annelida)Download PDFAbstract
Annelid chaetae are a superior diagnostic character on species and supraspecific levels, because of their structural variety and taxon specificity. A certain chaetal type, once evolved, must be passed on to descendants, to become characteristic for supraspecific taxa. Therefore, one would expect that chaetal diversity increases within a monophyletic group and that additional chaetae types largely result from transformation of plesiomorphic chaetae. In order to test these hypotheses and to explain potential losses of diversity, we take up a systematic approach in this paper and investigate chaetation in Eunicida. As a backbone for our analysis, we used a three-gene (COI, 16S, 18S) molecular phylogeny of the studied eunicidan species. This phylogeny largely corresponds to previous assessments of the phylogeny of Eunicida. Presence or absence of chaetal types was coded for each species included into the molecular analysis and transformations for these characters were then estimated using the mK1 likelihood model. Our results show that chaetal type diversity does indeed increase within eunicids and provide possible explanations for the homology, convergence, and loss of chaetal types in eunicidan subtaxa.
Received: 13 August 2015 / Accepted: 22 October 2015 / Published online: 31 October 2015
Topography and climatic fluctuations boosting speciation: biogeography and a molecular phylogeny of the East African genera Afroanthracites Hemp & Ingrisch and Afroagraecia Ingrisch & Hemp (Orthoptera, Tettigoniidae, Conocephalinae, Agraeciini)Download PDFAbstract
Based on faunistic lists documenting the distribution of taxa and molecular data, a phylogenetic tree of African Agraeciini is presented and detailed hypotheses of speciation patterns discussed. It is discussed that the observed radiation in the geologically old Eastern Arc chain is young since Afroanthracites montium endemic to Mts. Kilimanjaro and Meru is of the same age as species of the East and West Usambara Mountains. A molecular phylogeny on nine Afroanthracites and four Afroagraecia species is presented in this study prepared on the molecular markers 16S rRNA and histone 3. The molecular results confirmed geographical patterns and morphological relationships in Afroanthracites as well as in Afroagraecia.
Received: 07 July 2015 / Accepted: 06 October 2015 / Published online: 15 October 2015
Interrelationships of NemertodermatidaDownload PDFAbstract
Nemertodermatida is a small taxon of microscopic marine worms, which were originally classified within Platyhelminthes. Today they are hypothesized to be either an early bilaterian lineage or the sister group to Ambulacraria within Deuterostomia. These two hypotheses indicate widely diverging evolutionary histories in this largely neglected group. Here, we analyse the phylogeny of Nemertodermatida using nucleotide sequences from the ribosomal LSU and SSU genes and the protein coding Histone 3 gene. All currently known species except Ascoparia neglecta and Ascoparia secunda were included in the study in addition to several yet undescribed species. Ascopariidae and Nemertodermatidae are retrieved as separate clades, although not in all analyses as sister groups. Non-monophyly of Nemertodermatida was rejected by the Approximately Unbiased test. Nemertodermatid nucleotide sequences deposited in Genbank before 2013 were validated against our dataset; some of them are shown to be chimeric implying falsification of prior hypotheses about nemertodermatid phylogeny: other sequences should be assigned new names. We also show that the genus Nemertoderma needs revision.
Published online: 01 April 2016
Twenty years into the “new animal phylogeny”: Changes and challengesDownload PDF
Received: 15 March 2016 / Accepted: 16 May 2016 / Published online: 21 May 2016
Taxonomics—next-generation taxonomistsDownload PDFAbstract
“Taxonomics” is proposed as a short name for the discipline of discovering, recognising, describing and classifying biological entities.
Received: 18 June 2015 / Accepted: 30 November 2015 / Published online: 15 December 2015
Background noise as a selective pressure: stream-breeding anurans call at higher frequenciesDownload PDFAbstract
Acoustic signals are an important part in the behaviour of many species and may play a key role in speciation. However, little is known about the importance of natural selection on the evolution of such signals. Acoustics signals are the main communication channel for most anuran species, and background noise from streams is a constant source of masking interference for species reproducing in these environments. Herein, we test if the noise of flowing water habitats has favoured advertisement calls with higher dominant frequencies in frogs. Phylogenetic generalized least square model analysis revealed a significant influence of reproductive environment and body size on dominant frequency, with no significant interaction between habitat and body size. While stream breeders call at higher dominant frequencies, this acoustic parameter is inversely correlated with body size in both environments. We discuss the biological consequences of long-term adaptive shift in this acoustic parameter and possible trade-offs with other evolutionary forces.
Received: 29 June 2015 / Accepted: 11 November 2015 / Published online: 19 November 2015
The structure of the muscular and nervous systems of the female Intoshia linei (Orthonectida)Download PDFAbstract
The systematic position of the Orthonectida remains enigmatic. According to a classical point of view, they are placed together with Dicyemida in the phylum Mesozoa. Traditionally, orthonectids are regarded as rather primitive organisms, lacking digestive, muscular, and nervous systems. Here, using confocal laser scanning microscopy (CLSM) and immunohistochemical methods, we describe the musculature and serotoninergic nervous system of female adults of Intoshia linei (Orthonectida). The whole muscular system consists of 4 longitudinal and 9–11 circular muscle cells. The general muscular topography corresponds to the typical pattern for small-sized annelids or flatworms. Immunohistochemistry reveals six serotonin-like cells, which form part of a small nervous system comprising only 10–12 total cells based on nuclear counts. This is the first finding of a serotoninergic nervous system in orthonectids. Our analysis of muscular and neural organization in Orthonectida reveals significant differences from Diciemyda and aligns it more closely with the Lophotrochozoa.