Received: 15 February 2016 / Accepted: 04 October 2016 / Published online: 15 February 2016
Sympatric lineage divergence in cryptic Neotropical sweat bees (Hymenoptera: Halictidae: Lasioglossum)Download PDFAbstract
Given ongoing biodiversity decline, an important concern is that a large fraction of species diversity is not yet documented. Correct delimitation of species remains a challenge, especially for small and morphologically uniform groups such as sweat bees (Halictidae). Here, we applied an integrative taxonomic approach to study diversity within the Neotropical sweat bee subgenus Dialictus (genus Lasioglossum). We used four statistical methods to delimit species based on cytochrome oxidase subunit I gene sequences: Automatic Barcode Gap Discovery (ABGD), two variants of the General Mixed Yule Coalescent (single-threshold (stGMYC) and Bayesian (bGMYC)) and the Refined Single Linkage analysis (RESL). We detected eight principal molecular operational taxonomic units (mOTUs). Subsequently, these lineages were evaluated using ten nuclear microsatellite loci and morphological and ecological analyses. Most mOTUs could be differentiated using microsatellites and morphology (82 % identified correctly), further supporting the status of mOTUs as independent biological units. For the two most widespread mOTUs, we analysed intra-lineage geographic variation using microsatellites but did not detect additional substructuring. We further tested if the lineages showed predictable patterns of co-occurrence and habitat preferences. While we did not find any evidence of preferential association or disassociation between taxa, we detected a slight positive effect of high crop cover favouring the abundance of some lineages. We show that integrated approaches using statistical analysis of DNA barcodes jointly with additional data can provide robust and objective means of delimiting species in morphologically difficult groups.
Received: 07 June 2017 / Accepted: 20 July 2017 / Published online: 07 June 2017
Pattersoniomyces tillandsiae gen. et comb. nov.: linking sexual and asexual morphs of the only known smut fungus associated with BromeliaceaeDownload PDFAbstract
The enigmatic species Ustilago tillandsiae is the only known smut fungus associated with Bromeliaceae. Its generic position is evaluated by morphological, physiological, and molecular phylogenetic analyses using large subunit rDNA sequences. Phylogenetic analyses resolved U. tillandsiae as a member of the Ustilaginales in a sister relationship to the lineage containing Tranzscheliella species. However, U. tillandsiae differs from Tranzscheliella species by the development of sori in flowers, a different structure of sori and a different type of spore ornamentation. Consequently, a new genus Pattersoniomyces is described to accommodate U. tillandsiae. The new combination Pattersoniomyces tillandsiae is substantiated. In the sexual stage (teleomorph), this species infects bromeliads: Tillandsia flabellata, Tillandsia leiboldiana, and Tillandsia sp. in Central America between southern Mexico and Costa Rica. The yeast stage (anamorph) of P. tillandsiae was found associated with the phylloplane of Canistrum improcerum and in water tanks (phytotelmata) of Vriesea minarum, two bromeliads occurring in northeast and southeast Brazil, respectively. The link between the teleomorph and anamorphic strains is supported by identical sequences of the D1/D2 domains of the large subunit rDNA. Pattersoniomyces represents the tenth endemic smut genus to the Americas, but the only one that occurs in both North and South America, being a truly neotropical genus. The host plant families of Ustilaginales are extended to the Bromeliaceae. As far as we know, Pattersoniomyces represents the single event of a host jump from Cyperaceae or Poaceae to Bromeliaceae, apparently without further species radiation on multiple bromeliad species and genera growing in South America.
Received: 10 July 2016 / Accepted: 24 May 2017 / Published online: 10 July 2016
Recombination provides evidence for ancient hybridisation in the Silene aegyptiaca (Caryophyllaceae) complexDownload PDFAbstract
Recombination events among distinct alleles complicate phylogenetic estimation. Various in vivo and in vitro processes can bring distinct alleles into the same genome to then undergo recombination, which may subsequently mislead phylogenetic inference if not assessed properly. Among the processes bringing divergent alleles together, hybridisation is perhaps the simplest and most likely, but alternatives need to be considered before hybridisation can be accepted as the underlying cause. Such alternatives include the presence of paralogues or deeply coalescing alleles, as well as amplification artefacts. Here, we document a recombination event that apparently took place between two divergent lineages of the Silene aegyptiaca complex in the flowering plant family Caryophyllaceae. We evaluate several possible mechanisms that might be responsible for the observed pattern. An ancient introgressive hybridisation event was the simplest explanation for the observations, compatible with geographic proximity of the affected lineages, whereas paralogy and deep coalescence are difficult to reconcile with the evidence obtained from a species tree of the group based on six different, non-recombinant genes and gene trees inferred using two partitions of the recombinant locus.
Received: 21 April 2017 / Accepted: 05 September 2017 / Published online: 21 April 2017
Evolution of the claustrum in Cnidaria: comparative anatomy reveals that it is exclusive to some species of Staurozoa and absent in CubozoaDownload PDFAbstract
The claustrum in Cnidaria is a tissue in the gastrovascular cavity delimited by a central layer of mesoglea surrounded by gastrodermis (i.e., gastrodermis-mesoglea-gastrodermis), without communication with epidermis. By dividing the gastrovascular cavity, the four claustra provide an additional level of complexity. The presence of claustra in Cubozoa and Staurozoa has been used as evidence supporting a close relationship between these two cnidarian classes. However, the detailed anatomy of the claustrum has never been comparatively analyzed, rendering the evolution of this character among Cnidaria and its homology in Staurozoa and Cubozoa uncertain. This study provides a comparative investigation of the internal anatomy of the claustrum in Staurozoa and Cubozoa, addressing its evolutionary history based on recent phylogenetic hypotheses for Cnidaria. We conclude that the claustrum is a character exclusive to some species of Staurozoa, with a homoplastic evolution in the class, and that the structure called the “claustrum” in Cubozoa corresponds to the valve of gastric ostium, a structure at the base of the manubrium, which is also present in Staurozoa with and without claustrum. Thus, the claustrum cannot be a synapomorphy of a hypothetical clade uniting Staurozoa and Cubozoa, nor can its hypothetical presence in enigmatic fossils be used to support cubozoan affinities.
Erratum to: Diversification of Caiophora (Loasaceae subfam. Loasoideae) during the uplift of the Central AndesDownload PDF
Received: 24 March 2016 / Accepted: 22 July 2016 / Published online: 24 March 2016
A vanishing hotspot—the impact of molecular insights on the diversity of Central European Bythiospeum Bourguignat, 1882 (Mollusca: Gastropoda: Truncatelloidea)Download PDFAbstract
The current study investigates the Central European groundwater snails of the genus Bythiospeum which are currently regarded as highly diverse with a hotspot in south-western Germany coupled with high rates of endemism. This systematic concept combined with the fragility of their habitat results in a high rate of threatened species (76–96 %). The analyses of the mitochondrial COI fragment of nearly 200 specimens from 35 localities in Germany, Switzerland and marginally Austria and France including type localities of 14 taxa revealed five well-distinguished clades with genetic distances from 3.6 to 16.4 % while variability within clades and populations is very low. Morphological investigations focused on parts of the reproductive systems showed rather great uniformity with only minor differences in penis shape, size and localisation. Previous species concepts based on conchology and morphology do not correspond to the current results, and shell shape is suspected as poor indicator for species delineation. Our data indicate a significantly lower diversity in Central Europe, e.g. only three species occurring in Germany instead of 25. Taxonomic implications of our hypothesis are given and discussed. Accordingly, most of the German populations belong to Bythiospeum acicula (Held, 1838) while B. husmanni (C. R. Boettger, 1963) is a very restricted relict. In comparison with other groundwater organisms, two of the more northerly distributed species show a large range stretching over at least 410 or 490 km respectively. Post-glacial re-colonisation from refugia is discussed as most likely explanation of the recent distribution pattern.
Received: 21 January 2017 / Accepted: 24 May 2017 / Published online: 21 January 2017
Cryptic and pseudo-cryptic diversity in the world’s most common bark beetle—Hypothenemus eruditus
Hypothenemus eruditus is regarded as the world’s most common bark beetle, collected from numerous host plants on all forested continents. Previous taxonomic treatments remark that the species is morphologically variable and difficult to identify, but to date, no study has analyzed molecular data to investigate possible cryptic or seemingly cryptic (pseudo-cryptic) diversity in this species. We sequenced 216 specimens matching or closely resembling the currently accepted description of H. eruditus for a mitochondrial (COI) and a nuclear marker (28S), and scored six morphological characters. We also compared the morphology of H. eruditus syntypes and type material of 26 synonymized species with the sequenced material. The sequenced material grouped in 21 operational taxonomic units (OTUs) supported by both molecular and morphological data, 17 of which were part of an apparent H. eruditus species complex. Another nine cryptic OTUs, distinguishable only by molecular data, were also included in the complex. Only one of the OTUs revealed a morphological match with the H. eruditus syntypes. The 26 synonymized species were split into 14 tentative morphs, 11 of which did not match the H. eruditus syntypes. We argue that many of our sequenced OTUs deserve species status, and that many species synonymized under H. eruditus should be resurrected.
Received: 18 December 2015 / Accepted: 30 June 2016 / Published online: 18 December 2015
From a lost world: an integrative phylogenetic analysis of Ansonia Stoliczka, 1870 (Lissamphibia: Anura: Bufonidae), with the description of a new speciesDownload PDFAbstract
While the island of Borneo is considered a global biodiversity hotspot, the species richness in many groups remains unknown and appears underestimated. During herpetological surveys carried out in the interior of Sarawak, East Malaysia, several individuals of a small species of the genus Ansonia Stoliczka 1870 were collected on the Usun Apau plateau and in the Gunung Hose mountain range (Ansonia sp. Usun Apau). An integrative taxonomic approach comprising phylogenetic (2.4 kb mitochondrial rDNA fragment, Bayesian Inference and Maximum Likelihood, >5.1 % to its closest relative) and morphometric analyses (25 measurements, multivariate ratio analysis and linear discriminant analysis), as well as morphological comparisons support the status of this operational taxonomic unit as a separate taxon at species level. The obtained phylogenetic hypothesis corroborates the two major clades within Ansonia found in previous studies. Within Clade One Ansonia sp. Usun Apau and the enigmatic Ansonia torrentis are part of a monophyletic group of the Bornean species Ansonia hanitschi, Ansonia minuta, Ansonia platysoma, Ansonia spinulifer, Ansonia vidua, and two additional undescribed taxa. This subclade must be considered as the result of an on-island radiation in the complex evolution of Ansonia. The new species is formally described including the identification of diagnostic morphometric traits. Ansonia sp. Usun Apau is endemic to two isolated mountain ridges in central Sarawak and must be considered as a new element of the unique diversity of the Bornean amphibian fauna that is potentially threatened by habitat loss at least in parts of its range.
Received: 29 August 2016 / Accepted: 12 December 2016 / Published online: 29 August 2016
Polycladida phylogeny and evolution: integrating evidence from 28S rDNA and morphologyDownload PDFAbstract
Polyclad flatworms have a troubled classification history, with two contradicting systems in use. They both rely on a ventral adhesive structure to define the suborders Acotylea and Cotylea, but superfamilies were defined according to eyespot arrangement (Prudhoe’s system) or prostatic vesicle characters (Faubel’s system). Molecular data available cover a very limited part of the known polyclad family diversity and have not allowed testing morphology-based classification systems on Polycladida yet. We thus sampled a suitable marker, partial 28S ribosomal DNA (rDNA), from Polycladida (19 families and 32 genera), generating 136 new sequences and the first comprehensive genetic dataset on polyclads. Our maximum likelihood (ML) analyses recovered Polycladida, but the traditional suborders were not monophyletic, as the supposedly acotyleans Cestoplana and Theama were nested within Cotylea; we suggest that these genera should be included in Cotylea. The partial 28S rDNA trees were generally well supported and robust but in conflict with both Faubel’s and Prudhoe’s superfamilies. Therefore, we compiled morphological and anatomical characters for all taxa used and examined their distribution on our molecular tree. Combining morphological and molecular evidence, we redefined polyclad superfamilies. Acotylea contain tentaculated and atentaculated groups and is now divided in three superfamilies. The suborder Cotylea can be divided in five superfamilies. In general, there is a trait of anteriorization of sensory structures, from the plesiomorphic acotylean body plan to the cotylean gross morphology. Traditionally used characters, such as prostatic vesicle, eyespot distribution, and type of pharynx, are all homoplastic and likely have misled polyclad systematics so far.
Received: 19 December 2016 / Accepted: 05 September 2017 / Published online: 19 December 2016
Revision of the genus complex Gibbula: an integrative approach to delineating the Eastern Mediterranean genera Gibbula Risso, 1826, Steromphala Gray, 1847, and Phorcus Risso, 1826 using DNA-barcoding and geometric morphometrics (Vetigastropoda, Trochoidea)Download PDFAbstract
The trochoid genus, Gibbula, is abundant and diverse in the Mediterranean Sea but problematic to identify and delineate. This is due to highly variable shell morphology, vague original descriptions, and missing or unspecific type material. In recent studies, COI barcoding yielded satisfactory results for species delineation. In the present study, a combination of geometric shell morphometric methods and COI barcoding was used to assess the most abundant species of the Eastern Mediterranean. All relevant identification characters were captured via standardised images of the shells in both lateral and ventral views. Agreeing with previous studies, Gibbula was recovered as paraphyletic in the molecular analysis and thus is restricted to the clade encompassing the type species Gibbula magus (Linnaeus, 1758). The geometric morphometric analyses and the barcoding approach clearly distinguish the remaining species into two groups: the genus Steromphala Gray, 1847 and the genus Phorcus Risso, 1826. Type material was used for the geometric morphometric analyses whenever possible. Based on re-examination of the original type descriptions, lectotypes were designated. The joint application of DNA-barcoding and geometric morphometrics not only effectively delineated the sister genera Steromphala and Phorcus but also delineated all analysed species in the Gibbula-Steromphala-Phorcus genus complex. The additional use of geometric morphometrics enables researchers to compare barcoded material with fossil specimens or dry collections in an objective way.
Received: 24 March 2016 / Accepted: 14 June 2016 / Published online: 24 March 2016
Climatic niche evolution in the Andean genus Menonvillea (Cremolobeae: Brassicaceae)Download PDFAbstract
The study of how climatic niches change over evolutionary time has recently attracted the interest of many researchers. Different methodologies have been employed principally to analyze the temporal dynamics of the niche and specially to test for the presence of phylogenetic niche conservatism. Menonvillea, a genus of Brassicaceae including 24 species, is distributed primarily along the Andes of Argentina and Chile, with some taxa growing in southern Patagonia and others in the Atacama Desert and the Chilean Matorral. The genus is highly diversified morphologically but also presents a remarkably wide ecological range, growing from the high Andean elevations, to the dry coastal deserts in Chile, or the Patagonia Steppe in Argentina. In this study, we used molecular phylogenies together with climatic data to study climatic niche evolution in the genus. The results show that the main climatic niche shifts in Menonvillea occurred between the sections Cuneata-Scapigera and sect. Menonvillea throughout the Mid-Late Miocene, and associated with the two main geographical distribution centers of the genus: the highlands of the central-southern Andes and the Atacama Desert-Chilean Matorral, respectively. Climatic niches in these lineages were mainly differentiated by the aridity and potential evapotranspiration, the minimum temperatures of the coldest month, and the temperature annual range and seasonality. Niche evolution in Menonvillea deviated from a Brownian motion process, with most of the climatic dimension best-fitting to an Ornstein-Uhlenbeck model of multiple adaptive peaks. Our results also indicated that higher aridity levels and lower annual temperature ranges were associated with the evolution of the annual habit, as exemplified by the distribution of sect. Menonvillea. Finally, the results suggested that climatic niche evolution in Menonvillea exhibited some degree of phylogenetic niche conservatism, fundamentally within the two main lineages (sect. Menonvillea and sects. Cuneata-Scapigera).
Received: 29 November 2016 / Accepted: 02 March 2017 / Published online: 29 November 2016
Anthopleura and the phylogeny of Actinioidea (Cnidaria: Anthozoa: Actiniaria)Download PDFAbstract
Members of the sea anemone genus Anthopleura are familiar constituents of rocky intertidal communities. Despite its familiarity and the number of studies that use its members to understand ecological or biological phenomena, the diversity and phylogeny of this group are poorly understood. Many of the taxonomic and phylogenetic problems stem from problems with the documentation and interpretation of acrorhagi and verrucae, the two features that are used to recognize members of Anthopleura. These anatomical features have a broad distribution within the superfamily Actinioidea, and their occurrence and exclusivity are not clear. We use DNA sequences from the nucleus and mitochondrion and cladistic analysis of verrucae and acrorhagi to test the monophyly of Anthopleura and to evaluate the pattern of distribution of acrorhagi and verrucae. We find that Anthopleura is paraphyletic: although species of the genus cluster together, some groups also include members of genera like Bunodosoma, Aulactinia, Oulactis, and Actinia. This paraphyly is explained in part by the discovery that acrorhagi and verrucae are pleisiomorphic for the subset of Actinioidea studied.
Received: 07 July 2016 / Accepted: 04 October 2016 / Published online: 07 July 2016
Cephalic anatomy and three-dimensional reconstruction of the head of Catops ventricosus (Weise, 1877) (Coleoptera: Leiodidae: Cholevinae)Download PDFAbstract
Adult head structures are well known in the coleopteran suborders Archostemata and Adephaga, whereas the available information is very fragmentary in the megadiverse Polyphaga, including the successful superfamily Staphylinoidea. In the present study, the cephalic morphology of the cholevine species Catops ventricosus is described in detail and documented. The results were compared to conditions occurring in other polyphagan lineages, especially staphylinoid and scarabaeoid representatives. Specific external features documented in Catops and potential autapomorphies of Leiodidae include a five-segmented antennal club with a reduced eighth antennomere and the presence of periarticular grooves filled with sensilla on antennomeres 7, 9, and 10. The firm connection of the head and pronotum is possibly an apomorphy of Cholevinae. The monophyly of Cholevinae excluding Eucatopini and Oritocatopini is supported by the apical maxillary palpomere as long as or shorter than the subapical one, and the presence of cryptic pore plates on the surface of these palpomeres—a feature described and documented here for the first time. The internal cephalic structures of Catops are mostly plesiomorphic, as for instance the complete tentorium. The pattern of the muscles is similar to what is found in other staphylinoid taxa. The unusual maxillary muscle “Mx” is likely a groundplan apomorphy of the clade Staphyliniformia + Scarabaeoidea. M. hypopharyngomandibularis (M13) was identified in Catops and is ancestral for Coleoptera, even though it is often missing. The same applies to M. tentoriohypopharyngalis (M42).
Received: 06 March 2017 / Accepted: 14 July 2017 / Published online: 06 March 2017
Morphological dissection of behavior: thoracic musculature clarifies independent development of jumping mechanisms between sister groups, planthoppers and leafhoppers (Insecta: Hemiptera: Auchenorrhyncha)Download PDFAbstract
Morphological and behavioral characters are frequently examined for comparative studies. Unlike morphology, a single behavioral trait is difficult to subdivide as multiple characters, even when achieved by many evolutionary changes. Therefore, when similar behavioral traits evolved independently among closely related taxa, their distinction is difficult. Almost all members of the suborder Auchenorrhyncha (Insecta: Hemiptera) possess a jumping ability that uses metathoracic muscles, and this behavioral trait has been regarded as a synapomorphy. In this study, the anatomical observations of metathoracic muscles revealed that highly elaborated jumping ability was gained independently within the suborder, although the evolution of jumping ability might have been initiated at their common ancestor. Our results provide an example of identifying a true evolutionary pathway by dissecting a behavioral character into mechanical elements.
Received: 24 June 2016 / Accepted: 06 January 2017 / Published online: 24 June 2016
Historical biogeography and mitogenomics of two endemic Mediterranean gorgonians (Holaxonia, Plexauridae)Download PDFAbstract
Among the Mediterranean plexaurids, four species are endemic and despite their ecological importance, comprehensive studies on the evolution and biogeography of these organisms are lacking. Here, we explore the mitogenomic variability of two endemic, ecologically important Mediterranean Paramuricea species. We assess their phylogenetic relationships and provide first insights into their evolution and biogeography. Complete mitogenome sequences of Paramuricea clavata and Paramuricea macrospina were obtained using long-range PCR, primer-walking and Sanger sequencing. For an enlarged sample of Paramuricea species, maximum likelihood and Bayesian phylogenetic trees of the mitochondrial gene mtMutS were obtained and used to study the biogeographic history of Paramuricea through a statistical Dispersal-Vicariance (S-DIVA) method and a Dispersal Extinction Cladogenesis (DEC) model. Divergence time was estimated under strict and relaxed molecular clock models in BEAST using published octocoral mutation rates. Our results revealed high nucleotide diversity (2.6%) among the two Mediterranean endemics; the highest mutation rates were found in the mtMutS, Nad4 and Nad5. In addition, we found length polymorphisms in several intergenic regions and differences in mitochondrial genome size. The red gorgonian P. clavata was closely related to the Eastern Atlantic Paramuricea grayi rather than its Mediterranean congener, P. macrospina. Our biogeographic results provide evidence for the independent speciation of the Mediterranean species and point to a Miocene origin of the two endemics, highlighting the role played by the Messinian Salinity Crisis in the evolutionary history of Mediterranean organisms.
Received: 09 May 2016 / Accepted: 19 October 2016 / Published online: 09 May 2016
Bipolarity in sea slugs: a new species of Doridunculus (Mollusca: Nudibranchia: Onchidoridoidea) from AntarcticaDownload PDFAbstract
Bipolar distributions of benthic taxa have intrigued many biologists since the first Antarctic expeditions. Records of taxa, either at species or higher taxonomic levels, encompassing this peculiar distribution have been regularly reported since then. Moreover, the study of heterobranch mollusks from remote areas, such as Antarctica, often provides key taxa so far unknown, which might be essential for systematics. Here, we describe a new species of nudibranch from the eastern Weddell Sea using micro-computed tomography (micro-CT), namely, Doridunculus punkus n. sp. (Akiodorididae). Hitherto, the genus Doridunculus was only reported from the Arctic region. We provide an extensive description of morphological and anatomical characters of D. punkus n. sp., thereby offering new insights into the anatomy of the understudied Akiodorididae. A comparison of all Akiodorididae species shows that D. punkus n. sp. exhibits intermediate characters between some Onchidoridoidea families (i.e., hook-shaped innermost lateral teeth). Furthermore, the detailed study of its reproductive system suggests a close relationship of both Akiodorididae and Goniodorididae. We suggest an Antarctic origin of Akiodorididae followed by dispersion and a subsequent speciation in the Arctic.
Received: 08 February 2017 / Accepted: 14 July 2017 / Published online: 08 February 2017
Reconstructed historical distribution and phylogeography unravels non-steppic origin of Caucasotachea vindobonensis (Gastropoda: Helicidae)Download PDFAbstract
Existing data on the phylogeography of European taxa of steppic provenance suggests that species were widely distributed during glacial periods but underwent range contraction and fragmentation during interglacials into “warm-stage refugia.” Among the steppe-related invertebrates that have been examined, the majority has been insects, but data on the phylogeography of snails is wholly missing. To begin to fill this gap, phylogeographic and niche modeling studies on the presumed steppic snail Caucasotachea vindobonensis were conducted. Surprisingly, reconstruction of ancestral areas suggests that extant C. vindobonensis probably originated in the Balkans and survived there during the Late Pleistocene glaciations, with a more recent colonization of the Carpatho-Pannonian and the Ponto-Caspian regions. In the Holocene, C. vindobonensis colonized between the Sudetes and the Carpathians to the north, where its recent and current distribution may have been facilitated by anthropogenic translocations. Together, these data suggest a possible non-steppic origin of C. vindobonensis. Further investigation may reveal the extent to which the steppic snail assemblages consist partly of Holocene newcomers.
Received: 28 August 2016 / Accepted: 24 May 2017 / Published online: 28 August 2016
First phylogenetic analysis of the tribe Oligaphorurini (Collembola: Onychiuridae) inferred from morphological data, with implications for generic classificationDownload PDFAbstract
Oligaphorurini represent tribe of the subfamily Onychiurinae, which currently comprises 5 genera and 53 species. The present study evaluated the monophyly of Oligaphorurini genera. We investigated phylogenetic relationships among 39 species, representing all extant genera of Oligaphorurini. Both equal- and implied-weighting parsimony analyses were used in phylogenetic reconstruction. The cladistic analyses were based on comprehensive survey of adults’ morphological characters because specimens suitable for molecular studies were not available for the majority taxa. The phylogenetic analysis resulted in the recognition of a monophyletic Chribellphorura, and strongly supported non-monophyly of the previously recognized genera Archaphorura, Dimorphaphorura, Micraphorura, and Oligaphorura. The following new synonymy is recognized: Oligaphorura = Dimorphaphorura syn. nov., = Micraphorura syn. nov., = Archaphorura syn. nov. The general classification of Oligaphorurini is followed by the diagnoses of genera and key to the all known species.
Received: 05 July 2016 / Accepted: 16 November 2016 / Published online: 05 July 2016
From Eastern Arc Mountains to extreme sexual dimorphism: systematics of the enigmatic assassin bug genus Xenocaucus (Hemiptera: Reduviidae: Tribelocephalinae)Download PDFAbstract
The Eastern Arc Mountains (EAM) have long been recognized as an area of extraordinary endemic biodiversity but have remained understudied compared to other biodiversity hotspots. The tribelocephaline assassin bug genus Xenocaucus China & Usinger, 1949, currently comprises two species known from the Uluguru Mountains of the EAM and Bioko Island in the Gulf of Guinea. Both species are based on single apterous and apparently eyeless female specimens. Based on collections resulting from extensive leaf litter sampling in Tanzania and Ethiopia, we here describe six new species, five based on females (Xenocaucus chomensis, n. sp., Xenocaucus kimbozensis, n. sp., Xenocaucus nguru, n. sp., Xenocaucus rubeho, n. sp., and Xenocaucus uluguru, n. sp.) and Xenocaucus ethiopiensis, n. sp., for which we discovered a macropterous male with well-developed eyes in addition to the apterous females. Molecular phylogenetic analyses indicate that Xenocaucus ethiopiensis, n. sp., is the sister taxon to the Tanzanian clade and support morphology-based species concepts. Divergence dating shows that diversification in the Tanzanian clade started ∼15 mya, with the youngest species-level split occurring ∼8 mya. Three species occur across multiple mountain ranges in the EAM or occur also on Mt. Hanang, and biogeographic analyses suggest a complex history of Xenocaucus in East Africa.
Received: 17 April 2017 / Accepted: 05 September 2017 / Published online: 17 April 2017
Cryptic diversity, sympatry, and other integrative taxonomy scenarios in the Mexican Ceratozamia miqueliana complex (Zamiaceae)Download PDFAbstract
According to the integrative taxonomy (IT) framework, delimitation of taxonomic specimens into bona fide species requires the incorporation of multiple sources of biological evidence that jointly perform a role as systematic criteria. Here, we collected a combination of geographic, morphological (qualitative and quantitative), and molecular data sets from a group of specimens in the Ceratozamia miqueliana species complex. We analyzed them under methods suitable for each of these partitions and then synthesized results under the taxonomic circle—i.e., an operational tool for inference in IT. Taxonomic circle-based species delimitations in this Ceratozamia species complex have downstream taxonomic-nomenclatural consequences given that morphometric affinity between these specimens does not allow their species-level identification. However, joint patterns of qualitative morphological (i.e., diagnostics in standard sense) and molecular (i.e., character-based, DNA diagnostic or “bar coding”) characters between the species suggest the following scenarios: (1) C. miqueliana is a morphologically diagnosable species that lacks DNA diagnostics; (2) Ceratozamia subroseophylla is diagnosable both in terms of morphological and molecular evidence and sympatric with C. miqueliana; (3) Ceratozamia euryphyllidia is diagnosable both in morphological and molecular terms; (4) Ceratozamia zoquorum and Ceratozamia santillanii are cryptic species, i.e., both have exclusive DNA diagnostics but are not diagnosable morphologically; and (5) Ceratozamia becerrae is not diagnosable by any criterion and should therefore fall in synonymy. The present work contributes to establish a robust platform for subsequent systematic assessments of Mexican cycad diversity, which could include new hypotheses on the evolutionary processes involved in their current biogeographic distribution, ecological relationships, and other life-history aspects, in turn useful for conservation biology concerns.
Received: 25 May 2016 / Accepted: 16 November 2016 / Published online: 25 May 2016
Diversification of Caiophora (Loasaceae subfam. Loasoideae) during the uplift of the Central AndesDownload PDFAbstract
Andean orogeny and the ecological changes that followed promoted diversification in plant and animal lineages since the Early Miocene. The angiosperm genus Caiophora (Loasaceae, subfam. Loasoideae) comprises around 50 species that are endemic to South America. These are distributed from southern Ecuador to Central Chile and Argentina. Bee pollination and distribution at low-intermediate elevations probably represent the ancestral condition in the lineage that includes Caiophora and its allied genera. The majority of Caiophora species grow at high elevations in the Andes, where some depend on vertebrate pollination. Previous studies did not resolve phylogenetic relationships within Caiophora, which precluded the dating of the origin and divergence of this group. We used markers of one nuclear (ITS) and one plastid region (trnS
) to solve phylogenetic relationships among 19 Caiophora species (including different accessions). We also included 10 species of the allied genera Blumenbachia and Loasa. Aosa rostrata and Xylopodia klaprothioides were used as outgroups. Phylogenetic reconstruction strongly supports the monophyly of Caiophora, and although several clades within this genus are poorly supported, our study yielded a better infra-generic resolution than previous studies. The origin of Caiophora is dated to the Early-Middle Miocene and can be related to the uplift of the Cordilleras Frontal and Principal and to Pacific marine transgressions. According to our estimations, Caiophora began to diversify during the Middle-Late Miocene and this unfolding proceeded eastwards during the Pliocene and the Pleistocene, in parallel to the uplift of different Andean mountain ranges.
Received: 26 August 2016 / Accepted: 13 March 2017 / Published online: 26 August 2016
The thoracic anatomy of the male and female winter moth Nyssiodes lefuarius (Lepidoptera: Geometridae) and evolutionary changes in the thorax of moths and butterfliesDownload PDFAbstract
The thoraces of males and flightless females of the geometrid winter moth Nyssiodes lefuarius are described, documented in detail, and compared. Morphological, functional, and evolutionary aspects of the female phenotype are discussed. The flightlessness of female N. lefuarius is linked not only with complex modifications of the skeletomuscular structure, especially elements of the flight apparatus, but also with greatly enlarged ovaries and a reduced gut. Compared with other flightless female lepidopterans, females of N. lefuarius display a specific thoracic skeletomuscular configuration, which strongly suggests independent evolution, in agreement with the phylogenetic pattern. The evolutionary scenario of flight ability enhancement in Lepidoptera is demonstrated using a combined phylogeny from recent studies based on molecular data. Thoracic skeletomuscular characters are compiled and mapped, mainly using extensive information from the literature, but also including the new morphological data obtained from the male N. lefuarius. Important changes in the thoracic character system are linked with the rise of Coelolepida, Heteroneura, and Ditrysia. Only minor changes take place in the character system in more advanced groups of Lepidoptera. A highly unusual feature is the secondarily stiff wing type in some groups of Ditrysia without the neopteran basal folding mechanism. The morphological background of the secondarily evolved “palaeopteran” condition is a complex of different character changes. Major problems in the reconstruction of the phylogeny are a high degree of homoplasy and missing detailed data for several crucial taxa emerging close to the root of the order.
Received: 17 February 2017 / Accepted: 14 July 2017 / Published online: 17 February 2017
Evolutionary relationships of wing venation and wing size and shape in Aphidiinae (Hymenoptera: Braconidae)Download PDFAbstract
We explored evolutionary changes in wing venation and wing size and shape in Aphidiinae, one of the well-known groups of parasitic wasps from the family Braconidae. Forewings of 53 species from 12 genera were examined, for which a molecular phylogeny was constructed on the basis of the mitochondrial barcoding gene COI. By covering all types of wing venation within the subfamily Aphidiinae and by using landmark-based geometric morphometrics and phylogenetic comparative methods, we tested whether evolutionary changes in wing shape correlate to the changes in wing venation and if both changes relate to wing size. The relationship between wing morphology and host specificity has been also investigated. We found that six types of wing venation, with different degree of vein reduction, could be recognized. Wing venation type is largely genus specific, except in the case of maximal reduction of wing venation which could be found across examined Aphidiinae taxa. The reconstruction of evolutionary changes in wing venation indicates that evolutionary changes in wing shape are related to the changes in wing size, indicating that miniaturization play a role in evolution of wing morphology while host specialization does not affect the wing shape within the subfamily Aphidiinae.
Received: 20 November 2015 / Accepted: 16 January 2017 / Published online: 20 November 2015
Tracking the variability of phenotypic traits on a molecular phylogeny: an example from scolopendrid centipedes in peninsular IndiaDownload PDFAbstract
Taxonomic studies on scolopendrid centipedes have often documented variability at the individual and population levels and applied those data to questions of species delimitation, but these investigations have mostly lacked an explicit phylogenetic framework. A molecular phylogeny and recent taxonomic revision for Indian species of the scolopendrid Digitipes Attems, 1930, permit variability of traditional taxonomic characters for Scolopendridae to be mapped onto a phylogeny. Based on their fit to the tree using maximum likelihood, reliable species-level characters include the number of glabrous antennal articles, presence of a median ridge on the tergites, and presence or absence of a tarsal spur on leg 20. Characters that are conserved within and diagnostic for particular species but labile within others (typically with geographic structure) include the first tergite with paramedian sutures, presence or absence of a lateral spine on the coxopleuron, and the number of spines in a ventromedial row on the ultimate leg prefemur. Comparisons with published accounts of variability in species of other scolopendrid genera, particularly Scolopendra and Otostigmus, show that Indian Digitipes has conserved morphology in some characters that are taxonomically useful elsewhere in the family, and most of its taxonomically informative characters have analogous patterns of variability in other genera. The approach used in this study to evaluate morphological variation in a phylogenetic framework can be applied to other taxa in which morphologically cryptic species have been reported and where species diagnosis requires a combination of characters.
Received: 14 June 2016 / Accepted: 16 November 2016 / Published online: 14 June 2016
Evolution and systematics of Green Bush-crickets (Orthoptera: Tettigoniidae: Tettigonia) in the Western Palaearctic: testing concordance between molecular, acoustic, and morphological dataDownload PDFAbstract
The genus Tettigonia includes 26 species distributed in the Palaearctic region. Though the Green Bush-crickets are widespread in Europe and common in a variety of habitats throughout the Palaearctic ecozone, the genus is still in need of scientific attention due to the presence of a multitude of poorly explored taxa. In the present study, we sought to clarify the evolutionary relationships of Green Bush-crickets and the composition of taxa occurring in the Western Palaearctic. Based on populations from 24 disjunct localities, the phylogeny of the group was estimated using sequences of the cytochrome oxidase subunit I (COI) and the internal transcribed spacers 1 and 2 (ITS1 and ITS2). Morphological and acoustic variation documented for the examined populations and taxa was interpreted in the context of phylogenetic relationships inferred from our genetic analyses. The trees generated in the present study supported the existence of three main lineages: “A”—composed of all sampled populations of Tettigonia viridissima and the Tettigonia vaucheriana complex, “B”—comprising Tettigonia caudata, Tettigonia uvarovi, and the Tettigonia armeniaca complex, and “C”—consisting of Tettigonia cantans. The present study provides the first phylogenetic foundation for reviewing the systematics of Tettigonia (currently classified mostly according to morphological characteristics), proposing seven new synonymies.
Received: 21 September 2016 / Accepted: 27 February 2017 / Published online: 21 September 2016
Phylogenetic analysis of the genus Argia Rambur, 1842 (Odonata: Coenagrionidae), based on morphological characters of larvae and mitochondrial DNA sequencesDownload PDFAbstract
The study of the evolutionary interrelationships among the species encompassed in the Neotropical genus Argia (Zygoptera: Coenagrionidae) has been neglected. The goal of this study is to infer the phylogenetic relationships among 36 species of Argia Rambur, 1842, using complementary data sets (i.e., larval morphology and mitochondrial DNA). The morphological data set comprises 76% of the larvae currently described for this genus and includes 97 morphological characters. From those, 47 characters have not been previously used in taxonomic studies involving dragonflies’ larvae. This is the first cladistic study based on larvae morphology for species within the suborder Zygoptera. Data partitions were analyzed individually, as well as total evidence, using parsimony and Bayesian inference as criteria for optimal-tree selection. The results support the monophyly of the North American species of Argia. This genus can be identified by the combination of eight synapomorphies, four of which are exclusively found in Argia. According to the optimal trees, the individual data sets (i.e., morphology and DNA sequences) have a high level of homoplasy, resulting in soft polytomies and low support for several nodes. The specific relationships of the terminal units differ between the phylogenies; nonetheless, there is historical congruence among them. Within Argia, five clades were consistently recovered. Most of those clades have been identified, at least in part, in previous phylogenetic and taxonomic studies. Indubitably, the morphological characters from larvae have historical signal useful for cladistic and taxonomic inference. Therefore, it should be a priority to pay more attention to this source of characters.
Received: 04 August 2016 / Accepted: 30 November 2016 / Published online: 04 August 2016
Against all odds: reconstructing the evolutionary history of Scrophularia (Scrophulariaceae) despite high levels of incongruence and reticulate evolutionDownload PDFAbstract
The figwort genus Scrophularia (Scrophulariaceae), widespread across the temperate zone of the Northern Hemisphere, comprises about 250 species and is a taxonomically challenging lineage displaying large morphological and chromosomal diversity. Scrophularia has never been examined in a large-scale phylogenetic and biogeographic context and represents a useful model for studying evolutionary history in the context of reticulation. A comprehensively sampled phylogeny of Scrophularia was constructed, based on nuclear ribosomal (ITS) and plastid DNA sequences (trnQ-rps16 intergenic spacer, trnL-trnF region) of 147 species, using Bayesian inference and maximum likelihood approaches. Selected individuals were cloned. A combination of coding plastid indels and ITS intra-individual site polymorphisms, and applying Neighbor-Net and consensus network methods for adequate examination of within-dataset uncertainty as well as among-dataset incongruence, was used to disentangle phylogenetic relationships. Furthermore, divergence time estimation and ancestral area reconstruction were performed to infer the biogeographic history of the genus. The analyses reveal significant plastid-nuclear marker incongruence and considerable amounts of intra-individual nucleotide polymorphism in the ITS dataset. This is due to a combination of processes including reticulation and incomplete lineage sorting, possibly complicated by inter-array heterogeneity and pseudogenization in ITS in the presence of incomplete concerted evolution. Divergence time estimates indicate that Scrophularia originated during the Miocene in Southwestern Asia, its primary center of diversity. From there, the genus spread to Eastern Asia, the New World, Europe, Northern Africa, and other regions. Hybridization and polyploidy played a key role in the diversification history of Scrophularia, which was shaped by allopatric speciation in mountainous habitats during different climatic periods.
Received: 27 January 2016 / Accepted: 22 July 2016 / Published online: 27 January 2016
Revised classification and phylogeny of an Afrotropical species group based on molecular and morphological data, with the description of a new genus (Coleoptera: Scarabaeidae: Onthophagini)Download PDFAbstract
The worldwide distributed Onthophagus genus comprises at present more than 2000 species, that often show a complicated and uncertain systematic history. In particular, the many Afrotropical species included in this genus have never been entirely reviewed after the division into 32 species groups proposed by d’Orbigny in 1913, although subsequent researches focusing on some of these species suggested that Onthophagus constituted a nonmonophyletic taxon. In order to highlight their phylogenetic relationships, the various Afrotropical species groups of d’Orbigny must thus be examined, and it would be advisable to study them separately to avoid misunderstanding. In this framework, the taxonomic position of the three species currently included in the 21st d’Orbigny group was examined. Both morphological and biomolecular analyses contributed in confirming that these species (i.e., Onthophagus caffrarius d’Orbigny, 1902; Onthophagus quadraticeps Harold, 1867; and Onthophagus signatus Fåhraeus, 1857) constituted a well-defined monophyletic group that cannot be maintained within the genus Onthophagus. Therefore, the Kurtops gen.n. is here described to accommodate these Afrotropical species, that are nevertheless always included within the Onthophagini tribe. On the basis of the phylogenetic relationships here elucidated, it was also emphasized that the new genus is strictly related to Digitonthophagus and Phalops; thus, it was proposed to include the three genera into a single clade of suprageneric rank naming it as Phalops complex.
Received: 23 November 2016 / Accepted: 09 February 2017 / Published online: 23 November 2016
Morphology and evolution of the nervous system in Gnathostomulida (Gnathifera, Spiralia)Download PDFAbstract
Within Spiralia, Gnathifera may represent the deepest branching lineage comprising the jaw worms Gnathostomulida and their sister group Micrognathozoa + Syndermata. Yet, very few nervous system studies have been conducted on this lineage of microscopic, jaw-bearing worms, limiting our understanding of the evolution of this organ system in Spiralia. The nervous system of representatives from all major groups of Gnathostomulida was here mapped using confocal laser scanning microscopy and immunohistochemistry. Their intra-epidermal, unsegmented nervous systems comprise an anterior brain and three to five ventral and two to four dorsal longitudinal nerves, connected by few transverse commissures. Neurites of the stomatogastric nervous system were found lining the pharynx and connecting to a prominent buccal ganglion. Supposedly, sensory ciliated cells in the pharynx and the gut were documented for the first time. Based on these morphological results, primary homologies of neural structures in Gnathostomulida and other Gnathifera were hypothesized and thereafter tested using parsimony. This first neurophylogeny of Gnathostomulida resulted in a topology congruent with molecular data, supporting the monophyly of Bursovaginoidea, Conophoralia, and Scleroperalia. From this topology, the evolution of the gnathostomulid nervous system was reconstructed. It suggests a specialization and diversification of cords and serotonin-like immunoreactive cell patterns from a plesiomorphic neuroarchitecture of three unsegmented nerve cords and a compact anterior brain and buccal ganglion. These plesiomorphic states resemble the nervous system of Micrognathozoa, and possibly the ancestral states of Spiralia.
Received: 13 January 2016 / Accepted: 07 August 2016 / Published online: 13 January 2016
Molecular phylogenies challenge the classification of Polymastiidae (Porifera, Demospongiae) based on morphologyDownload PDFAbstract
Polymastiidae Gray, 1867 is a worldwide distributed sponge family, which has a great significance for understanding of the demosponge deep phylogeny since the former order Hadromerida Topsent, 1894 has been recently split based on the molecular evidence and a new separate order has been established for the polymastiids. However, molecular data obtained from Polymastiidae so far are scarce, while the phylogenetic reconstruction based on morphology has faced a deficit of characters along with the vagueness of their states. The present study is a phylogenetic reconstruction of Polymastiidae based on novel data on two molecular markers, cytochrome oxidase subunit I and large subunit ribosomal DNA, obtained from a broad set of species. Monophyly of the family and nonmonophyly of four polymastiid genera are revealed, suggesting a high level of homoplasy of morphological characters, which are therefore not an appropriate base for the natural classification of Polymastiidae. Although the presented phylogenies cannot yet provide an alternative classification scheme, several strongly supported clades, which may be used as reference points in future classification, are recovered and three taxonomic actions are proposed: transfer of one species from Radiella to Polymastia Bowerbank, 1862; transfer of three species from Radiella Schmidt, 1870 to Spinularia Gray, 1867; and the consequent abandonment of Radiella.
Received: 18 May 2016 / Accepted: 04 October 2016 / Published online: 18 May 2016
Examining the retention of functional kleptoplasts and digestive activity in sacoglossan sea slugsDownload PDFAbstract
Solar-powered sea slugs (Sacoglossa: Gastropoda) have long captured the attention of laymen and scientists alike due to their remarkable ability to steal functional chloroplasts from their algal food, enslaving them to withstand long starvation periods. Recently, a wealth of data has shed insight into this remarkable relationship; however, the cellular mechanisms governing this process are still completely unknown. This study explores these mechanisms, providing insight into the chloroplast retention and delayed digestion, occurring within the slug’s digestive gland. We examine the relationships between functional chloroplast and lysosome abundances during starvation, in live material, for the long-term retaining species Elysia timida, the ambiguous long/short-term retaining Elysia viridis, and the short-term retaining Thuridilla hopei, to elucidate digestive differences that contribute to the development of functional kleptoplasty. Functional chloroplast and lysosome abundance are measured using chlorophyll a autofluorescence and the pH-dependent stain acridine orange. In each species, the number of chloroplasts and lysosomes is indirectly proportional, with the plastid density decreasing when starvation begins. We also present a new FIJI/Image J Plugin, the 3D—Accounting and Measuring Plugin, 3D-AMP, which enables the reliable analysis of large image sets.
Received: 09 June 2016 / Accepted: 04 October 2016 / Published online: 09 June 2016
Regional differentiation of felid vertebral column evolution: a study of 3D shape trajectoriesDownload PDFAbstract
Recent advances in geometric morphometrics provide improved techniques for extraction of biological information from shape and have greatly contributed to the study of ecomorphology and morphological evolution. However, the vertebral column remains an under-studied structure due in part to a concentration on skull and limb research, but most importantly because of the difficulties in analysing the shape of a structure composed of multiple articulating discrete units (i.e. vertebrae). Here, we have applied a variety of geometric morphometric analyses to three-dimensional landmarks collected on 19 presacral vertebrae to investigate the influence of potential ecological and functional drivers, such as size, locomotion and prey size specialisation, on regional morphology of the vertebral column in the mammalian family Felidae. In particular, we have here provided a novel application of a method—phenotypic trajectory analysis (PTA)—that allows for shape analysis of a contiguous sequence of vertebrae as functionally linked osteological structures. Our results showed that ecological factors influence the shape of the vertebral column heterogeneously and that distinct vertebral sections may be under different selection pressures. While anterior presacral vertebrae may either have evolved under stronger phylogenetic constraints or are ecologically conservative, posterior presacral vertebrae, specifically in the post-T10 region, show significant differentiation among ecomorphs. Additionally, our PTA results demonstrated that functional vertebral regions differ among felid ecomorphs mainly in the relative covariation of vertebral shape variables (i.e. direction of trajectories, rather than in trajectory size) and, therefore, that ecological divergence among felid species is reflected by morphological changes in vertebral column shape.
Received: 30 December 2015 / Accepted: 17 May 2016 / Published online: 30 December 2015
Ecological patterns strongly impact the biogeography of western Palaearctic longhorn beetles (Coleoptera: Cerambycoidea)Download PDFAbstract
We aim to unravel the biogeographic structuring of western Palaearctic longhorn beetles with focus on the location of different refugia, barriers to dispersal and postglacial range expansions with their particular filters. The interaction of different ecological features with these structures is analysed. The western Palaearctic was divided into 95 geographic entities. We produced presence-only matrices for all 955 Cerambycoidea species autochthonous to this area and derived species richness distributions and extracted faunal regions and faunal elements by cluster analyses and principal component analyses. Similar analyses were performed for sub-families and ecological groups. Longhorn beetles show a strong biogeographic structuring in the western Palaearctic. Species numbers strongly decrease to the north and west. Less mobile species and root feeders mostly contribute to the fauna of the Mediterranean region, whilst mobile species are more widespread. Feeders on broad-leaved trees dominate in western Europe, whilst feeders on coniferous trees are most important in northern Europe. Our results support multiple refugia in the Mediterranean region and underline the importance of Provence, Crimea and Crete as such refugia. Crete even might be an area of old endemism. The Atlanto- and the Ponto-Mediterranean regions are more strongly structured than assumed in classical biogeography. Mediterranean assemblages are mostly composed of non-flying species, root feeders and species with small distributions not found outside their glacial refugia. Tree feeders left their glacial retreats with their host plants. These range dynamics result in biogeographic structures with several dispersal barriers and filters composed of mountains, sea straits and climatic conditions.
Received: 11 January 2016 / Accepted: 04 October 2016 / Published online: 11 January 2016
Molecular and morphological delimitation of Australian Triops species (Crustacea: Branchiopoda: Notostraca)—large diversity and little morphological differentiationDownload PDFAbstract
Australia has a very rich and diverse large branchiopod fauna with approximately 140 described or provisionally delimited species, but only one species of Triops, Triops australiensis (Spencer and Hall 1895), is currently recognized. Previous studies identified extensive genetic diversity within T. australiensis that suggested the presence of cryptic species. Herein, we employed an integrative approach to taxonomy to delimit putative species, integrating COI and EF1α sequence data and morphological data. Putative species were initially delimited based on COI by two computational approaches (GMYC and ABGD). The results were interpreted in the light of several species concepts, with particular emphasis on reproductive isolation. Twenty to 27 genetic lineages were delimited. Of these, up to 26 represent species following an evolutionary or phylogenetic species concept. Eighteen are biological species, though reproductive isolation could not be unambiguously established for allopatric species or species without known males. The level of co-occurrences was exceptionally high for Triops, with up to three syntopic and six sympatric species. Species delimitation was impeded by extensive overlap between intraspecific variability and interspecific variation in the genetic as well as morphological datasets. Without prior delimitation of putative species via COI, morphological delimitation would have been impossible. A potential explanation for the morphological variability is the retention of ancestral polymorphisms over long periods of time and across multiple speciation events without subsequent differentiation.
Received: 03 January 2017 / Accepted: 13 April 2017 / Published online: 03 January 2017
Ultrastructural and immunocytochemical investigation of paramylon combined with new 18S rDNA-based secondary structure analysis clarifies phylogenetic affiliation of Entosiphon sulcatum (Euglenida: Euglenozoa)Download PDFAbstract
The phylogeny of phagotrophic euglenids is widely based on nuclear small subunit ribosomal DNA (18S rDNA) sequence data, but most analyses suffer from weakness in statistical support regarding the “connecting backbone” between monophyletic clades. Moreover, the position of Entosiphon has remained unclear. Testing the 18S rDNA capability for a phylogeny of phagotrophic euglenids, we isolated sequences of Peranema sp. and Ploeotia edaphica and utilized secondary structure data as a prerequisite for recognition of homologous positions. We found a unique, clade-specific nucleotide substitution in the deduced 18S rDNA helix 44. Since our 18S rDNA phylogenies could only in part resolve positions of phagotrophic lineages, but did not verify that of Entosiphon, we investigated the phagotrophic key taxa Peranema trichophorum, Petalomonas cantuscygni, Ploeotia costata, and Entosiphon sulcatum ultrastructurally. Additionally, we explored the presence or absence of the euglenid reserve carbohydrate paramylon by specific staining with monoclonal anti-β-1,3-glucan antibodies. Paramylon was found to be clearly present in P. trichophorum and E. sulcatum, but was absent in Pt. cantuscygni and Pl. costata. Combined results of our molecular, ultrastructural, and immunocytochemical investigations suggest that Entosiphon sulcatum is the sister taxon of a monophyletic euglenid crown clade, characterized by a helical pellicle, which we propose to rename. This phylogenetic affiliation is confirmed by a clade-specific primary absence of the unique nucleotide substitution in helix 44 and by the common presence of paramylon.
Received: 09 June 2016 / Accepted: 19 December 2016 / Published online: 09 June 2016
Using multi-locus sequence data for addressing species boundaries in commonly accepted lichen-forming fungal speciesDownload PDFAbstract
Accurate species delimitations are of great importance for effectively characterizing biological diversity. Our criteria for delimiting species have changed dramatically over the last decades with the increasing availability of molecular data and improvement of analytical methods to evaluate these data. Whereas reciprocal monophyly is often seen as an indicator for the presence of distinct lineages, recently diverged species often fail to form monophyletic groups. At the same time, cryptic species have repeatedly been detected in numerous organismal groups. In this study, we addressed the species delimitation in the crustose lichen-forming fungal genus Diploschistes using multilocus sequence data from specimens representing 16 currently accepted species. Our results indicate the presence of previously undetected, cryptic species-level lineages in the subgenus Limborina. In the subgenus Limborina, samples from different continents currently classified under the same species were shown to be only distantly related. At the same time, in parts of subgen. Diploschistes characterized by short branches, none of the currently accepted species formed monophyletic groups. In spite of the lack of monophyly in phylogenetic reconstructions, a multispecies coalescent method provided support for eight of the nine accepted species in subgen. Diploschistes as distinct lineages. We propose to reduce D. neutrophilus to synonymy with D. diacapsis and point out that additional sampling will be necessary before accepting additional species in subgen. Limborina.
Erratum to: Evolution and systematics of Green Bush-crickets (Orthoptera: Tettigoniidae: Tettigonia) in the Western Palaearctic: testing concordance between molecular, acoustic, and morphological dataDownload PDF
Received: 18 November 2015 / Accepted: 14 June 2016 / Published online: 18 November 2015
The first fossil Athyreini beetle (Coleoptera: Geotrupidae)Download PDFAbstract
The first fossil Athyreini in the subfamily of Bolboceratinae from the family of Geotrupidae, †Amberathyreus beuteli Bai et Zhang gen. et sp. nov., is described based on a specimen from the mid-Cretaceous Myanmar (Burmese) amber from northern Myanmar. Its external morphology (including 3D reconstruction of the head and pronotum) was analyzed and compared with all known genera of Athyreini. †Amberathyreus’ close relationship between Athyreini and Bolboceratini is supported. †Amberathyreus was likely active at night and lived in a lowland environment. The finding of †Amberathyreus greatly enrich our knowledge of Athyreini.
Received: 27 February 2017 / Accepted: 14 July 2017 / Published online: 27 February 2017
The marbled goby, Pomatoschistus marmoratus, as a promising species for experimental evolution studiesDownload PDFAbstract
Breeding and rearing the offspring through successive generations are mandatory in order to study evolutionary responses to anthropogenic impact in marine organisms. However, fish offer a limited number of marine model species that allow performing multigenerational experimental approaches. Here, we propose a novel breeding and rearing experimental model based on the marbled goby Pomatoschistus marmoratus (Risso 1810) which is representative of small (up to 65 mm total length), benthic species with a short life cycle. We devised a ‘full-sib/half-sib’ breeding design, and the resulting offspring were reared in captivity using a complex feeding protocol and a creative design of the tanks. Three families survived up to 160 days post-hatching (dph); one was reared at 24 °C and two at 18 °C. The families reared at 18 °C reached sexual maturity and spawned. The size range at sexual maturity of individuals reared in captivity was consistent with the one observed in nature. The possibility to complete the entire life cycle, from hatching to sexual maturity and spawning in P. marmoratus offers great perspectives for experimental evolution and quantitative genetics studies aimed at understanding the role of evolutionary processes in response to global changes.
Received: 29 July 2016 / Accepted: 16 November 2016 / Published online: 29 July 2016
Transcriptome profiling of Symbion pandora (phylum Cycliophora): insights from a differential gene expression analysisDownload PDFAbstract
Cycliophorans are characterized by a complex life cycle that involves an asexual generation and a sexual generation. The most prominent life cycle stage in both generations is the so-called feeding stage. Using RNA-Seq, we profiled differential gene expression between feeding stages from asexual and sexual generations to study this intergenerational shift. For this, we also generated a reference transcriptome for the cycliophoran Symbion pandora. We found that a total of 2660 contigs (more than 10% of the total transcriptome) correspond to genes that are expressed differentially in the feeding stages from the asexual generation as compared to the sexual feeding stages. Among these, 1236 genes are upregulated in the asexual stages as compared to the sexual stages. Conversely, 1424 genes are upregulated in the sexual stages as compared to the asexual stages. The asexual stages express genes predominantly related to RNA processing and splicing as well as protein folding, which suggests a high degree of regulation at the transcriptional and post-transcriptional levels. In marked contrast, the sexual stages highly express genes related to signal transduction and neurotransmission. This is the first time that a large whole-transcriptome RNA-Seq expression dataset has been generated for any cycliophoran. Moreover, this study provides important information for further studies on the molecular mechanisms that are involved in the shift from asexual to sexual generations in this still enigmatic group.
Received: 07 May 2016 / Accepted: 03 November 2016 / Published online: 07 May 2016
Comparative study of bisected proboscides of PycnogonidaDownload PDFAbstract
To comparatively describe “inner” pharynx armatures in pycnogonids, we bisected proboscides of Achelia langi (Dohrn, 1881), Anoplodactylus californicus Hall, 1912, Ascorhynchus castellioides Stock, 1957, Austrodecus glaciale Hodgson, 1907, Callipallene margarita (Gordon, 1932), Colossendeis macerrima Wilson, 1881, Endeis spinosa (Montagu, 1808), Nymphon macronyx Sars, 1877, Pallenopsis patagonica (Hoek, 1881), Pantopipetta sp., Pigrogromitus timsanus Calman, 1927, and Pycnogonum litorale (Strøm, 1762) and analyzed them with the scanning electron microscope (SEM). Moreover, proboscides were stained with actin green to visualize the muscle arrangement with fluorescence and confocal microscopes (A. langi) and were analyzed with microcomputed X-ray tomography (μCT; Ascorhynchus japonicus). As a result of our observations, sets of characters that vary between taxa are established. These traits include length and width of proboscis, shape and structure of the inner mouth opening, borders and armature of the antimeres, shape and position of denticle arrays and rows, relative length of pharyngeal filter apparatus, and arrangement and structure of the filter bristles. Analyses of these characters indicate a substantial variability on the pantopod’s proboscis inner surface probably as an adaptation to different food sources. Finally, we suggest that the presence of the oyster basket represents a ground pattern character of Pycnogonida.
Received: 18 January 2016 / Accepted: 30 June 2016 / Published online: 18 January 2016
Endemic diversification in the mountains: genetic, morphological, and geographical differentiation of the Hemidactylus geckos in southwestern ArabiaDownload PDFAbstract
In this study, we provide genetic, morphological, and geographical comparisons for 11 species of the southwestern Arabian radiation of Hemidactylus geckos, nine of which are endemic to the region. By using a coalescence-based species-tree reconstruction in combination with divergence time estimations and speciation probability testing, we show that most of the speciation events occurred in the Pliocene, which is more recent than previously thought based on calibrations of concatenated data sets. The current dating indicates that the changing climate at the beginning of the Pliocene, from hot and dry to cold and wet, is likely responsible for increased speciation in Hemidactylus. Analyses of geographic and altitudinal overlap of the species and their morphological differentiation show that most species do not occur in sympatry. Those that overlap geographically are usually differentiated by their altitudinal preference, head shape, body size, or their combination. Our results indicate that the topographically complex mountains of southwestern Arabia support a significant radiation of Hemidactylus geckos by allowing multiple allopatric speciation events to occur in a relatively small area. Consequently, we describe two new species endemic to the Asir Mountains of Saudi Arabia, H. alfarraji sp. n. and H. asirensis sp. n., and elevate two former subspecies of H. yerburii to a species level, H. montanus and H. pauciporosus.
Received: 01 March 2017 / Accepted: 20 June 2017 / Published online: 01 March 2017
Direct development in African squeaker frogs (Anura: Arthroleptidae: Arthroleptis) reveals a mosaic of derived and plesiomorphic charactersDownload PDFAbstract
Direct development has evolved independently several times in anurans and direct-developing species are characterized by large-scale developmental repatterning and a complete, or near complete, absence of most tadpole-specific structures. Earlier studies stressed the similarities among different direct-developing species, but more recent studies have indicated differences in the reduction of tadpole-specific structures among different taxa. Here, we describe egg deposition, clutch characteristics and embryonic development of the direct-developing squeaker frogs of the genus Arthroleptis, providing the first detailed description of direct development in Arthroleptidae. Embryonic development in Arthroleptis is characterized by the presence of an opercular fold that still encloses the developing forelimbs, the absence of external gills and an only moderately extended tail. A comparison with published information on other direct-developing anurans reveals broad dissimilarities in the formation of an opercular fold and very different tail morphology among different taxa. An egg tooth, often considered characteristic of direct-developing anurans, seems to be restricted to New World Terrarana. The embryonic diversity seen in direct-developing anuran taxa argues against simplistic assumptions about the evolution of direct development.
Received: 30 March 2017 / Accepted: 12 September 2017 / Published online: 30 March 2017
Phylogeny of Polycladida (Platyhelminthes) based on mtDNA dataDownload PDFAbstract
A phylogenetic analysis of Polycladida based on two partial mitochondrial genes (cox1 and 16S) is provided. The analysis includes 30 polyclad terminals that represent species from the two taxa which traditionally divide the groups Cotylea and Acotylea. Our phylogenetic analyses produced a well-supported hypothesis that confirms the monophyly of Polycladida, as well as Acotylea and Cotylea. Within Acotylea, there are two lineages not highly supported: on one hand, Leptoplanoidea (excluding Hoploplana elisabelloi) and one Stylochoidea member (Pseudostylochus intermedius) (classification sensu Faubel, 1983, 1984), and on the other hand, Stylochoidea members together with Discocelis tigrina and H. elisabelloi. The genera Stylochus and Imogine are not monophyletic. Within Cotylea, Pseudocerotidae and Euryleptidae are monophyletic, though not highly supported, while Prosthiostomidae is not. Euryleptoidea is paraphyletic. The genera Pseudobiceros and Pseudoceros are monophyletic and highly supported. Our results suggest that, within Acotylea, the prostatoid organs of Discocelis may have been derived from a prostatic vesicle. The genus Hoploplana could be included in Stylochoidea. Within Cotylea, the common ancestor of Euryleptidae and Pseudocerotidae might have been an aposematic animal with tentacles.
Received: 30 March 2016 / Accepted: 22 July 2016 / Published online: 30 March 2016
Integrating selection, niche, and diversification into a hierarchical conceptual frameworkDownload PDFAbstract
Recently, new phylogenetic comparative methods have been proposed to test for the association of biological traits with diversification patterns, with species ecological “niche” being one of the most studied traits. In general, these methods implicitly assume natural selection acting at the species level, thus implying the mechanism of species selection. However, natural selection acting at the organismal level could also influence diversification patterns (i.e., effect macroevolution). Owing to our scarce knowledge on multi-level selection regarding niche as a trait, we propose a conceptual model to discuss and guide the test between species selection and effect macroevolution within a hierarchical framework. We first assume niche as an organismal as well as a species’ trait that interacts with the environment and results in species-level differential fitness. Then, we argue that niche heritability, a requirement for natural selection, can be assessed by its phylogenetic signal. Finally, we propose several predictions that can be tested in the future by disentangling both types of evolutionary processes (species selection or effect macroevolution). Our framework can have important implications for guiding analyses that aim to understand the hierarchical perspective of evolution.
Received: 16 March 2016 / Accepted: 13 December 2016 / Published online: 16 March 2016
Extensive cryptic diversity in the cosmopolitan sludge worm Limnodrilus hoffmeisteri (Clitellata, Naididae)Download PDFAbstract
Limnodrilus hoffmeisteri Claparède, 1862 is a common freshwater worm, often regarded as an indicator of organic pollution. The taxonomic status of this species is controversial due to great variation in morphological features. Numerous morphological forms of L. hoffmeisteri are recorded in the literature, especially from Europe and North America. Today, DNA-based species delimitation assumes that species boundaries can be more objectively and effectively estimated using genetic data rather than with morphological data alone. To investigate if L. hoffmeisteri is a single species, 295 worms identified as either L. hoffmeisteri or other similar (congeneric) morphospecies, using currently accepted morphological criteria, were collected from 82 locations in the northern hemisphere. The number of primary species hypotheses (PSHs) was first explored with cytochrome oxidase subunit I (COI), the proposed DNA barcode for animal species, and with data for all specimens. Both automatic barcoding gap discovery (ABGD) and the Bayesian general mixed Yule coalescent (bGMYC) model revealed the existence of ≥25 distinct PSHs (COI lineages) in our dataset. Then, smaller samples of individuals representing major COI lineages were used for exploration of a nuclear locus, the internal transcribed spacer (ITS) region. In the ITS gene tree (81 sequences), generated by BEAST, 16 well-supported terminal groups were found, but not all of these groups were congruent with the PSHs found in the COI tree. As results across these different analyses were inconsistent, we resorted to analyzing reciprocal monophyly between gene trees and used a minimum consensus of all evidence, suggesting that there are 13 separately evolving lineages (=13 species) within our sample. The smallest uncorrected COI p-distance between these species is 12.1%, and the largest intraspecific p-distance is 16.4%, illustrating the problem of species delimitation with a DNA-barcoding gap as the sole criterion. Ten of these species are morphologically identified as “L. hoffmeisteri,” the remaining three can be attributed to morphologically distinct congeneric species. An individual from the type locality in Switzerland was designated as a neotype of L. hoffmeisteri sensu stricto. This worm belongs to one of the ten species, and this lineage is widely distributed in Europe, Asia, and North America. The remaining nine species show a mixed distribution pattern; some appear to be endemic to a restricted area, others are Holarctic. Our results provide clues to the future revalidation of some of the nominal species today placed in synonymy with L. hoffmeisteri. A BEAST analysis, based on previously published and newly generated 16S data, suggested that this complex contains also other species than those studied by us. By integrating additional genetic data, it will be possible to identify these and additional specimens in future studies of Limnodrilus, and the neotype provides a baseline for further revisions of the taxonomy of the L. hoffmeisteri complex.
Erratum to: Evaluation of traditionally circumscribed species in the lichen-forming genus Usnea, section Usnea (Parmeliaceae, Ascomycota) using a six-locus datasetDownload PDF
Received: 06 January 2017 / Accepted: 24 May 2017 / Published online: 06 January 2017
Concerted evolution, a slow process for ant satellite DNA: study of the satellite DNA in the Aphaenogaster genus (Hymenoptera, Formicidae)Download PDFAbstract
A family of satellite DNA is analyzed in seven ant species from the genus Aphaenogaster. This satellite DNA is organized as tandemly repeated sequences with a consensus sequence of 160 bp in length. The sampled sequences show a high similarity and belong to the same family of satellite DNA. However in Aphaenogaster spinosa, two types of repeat clearly differentiated have been found. Phylogenetic analyses using satellite DNA show that sequences do not cluster in a species-specific way, with one exception. Concretely, the second type of repeats of A. spinosa (APSP-II) which constitutes a new satellite DNA subfamily. The obtained results with satellite DNA are compared with those obtained using mitochondrial and nuclear DNA to determine the correlation between evolution of satellite DNA and phylogenetic relationships among the analyzed ants. The high interspecific similarity for the satellite DNA seems not to be in concordance with the concerted evolution pattern, commonly accepted to explain the evolution of satellite DNA. However, the accumulated data suggest that evolution of satellite DNA in ants follows the concerted evolution pattern but that this process is slow in relation with other organisms, probably due to the eusociality and haplodiploidy of these insects.
Received: 25 July 2016 / Accepted: 07 October 2017 / Published online: 25 July 2016
An evolutionary timescale for terrestrial isopods and a lack of molecular support for the monophyly of Oniscidea (Crustacea: Isopoda)Download PDFAbstract
The marine metazoan fauna first diversified in the early Cambrian, but terrestrial environments were not colonized until at least 100 million years later. Among the groups of organisms that successfully colonized land is the crustacean order Isopoda. Of the 10,000 described isopod species, ~ 3,600 species from the suborder Oniscidea are terrestrial. Although it is widely thought that isopods colonized land only once, some studies have failed to confirm the monophyly of Oniscidea. To infer the evolutionary relationships among isopod lineages, we conducted phylogenetic analyses of nuclear 18S and 28S and mitochondrial COI genes using maximum-likelihood and Bayesian methods. We also analyzed a second data set comprising all of the mitochondrial protein-coding genes from a smaller sample of isopod taxa. Based on our analyses using a relaxed molecular clock, we dated the origin of terrestrial isopods at 289.5 million years ago (95% credibility interval 219.6–358.9 million years ago). These predate the known fossil record of these taxa and coincide with the formation of the supercontinent Pangaea and with the diversification of vascular plants on land. Our results suggest that the terrestrial environment has been colonized more than once by isopods. The monophyly of the suborder Oniscidea was not supported in any of our analyses, conflicting with classical views based on morphology. This draws attention to the need for further work on this group of isopods.
Received: 17 October 2016 / Accepted: 13 January 2017 / Published online: 17 October 2016
Evolution and diversity of ram-suction feeding in damselfishes (Pomacentridae)Download PDFAbstract
The cerato-mandibular (c-md) ligament is a synapomorphy within Pomacentridae that creates a tight link between the lower jaws and the hyoid bars. However, this morphological trait has been secondarily lost in multiple lineages during evolution. A previous study revealed that the loss of this trait acted as a release of evolutionary constraints, leading to a cascade of morphological changes such elongated buccal jaws and a slender body. Ecomorphological interpretations suggested the loss of the c-md ligament has ultimately led to a new adaptive peak in zooplanktivory through an optimization of the ram feeding mode associated with a specialization in pelagic feeding. Here, we tested these hypotheses by comparing functional and diet diversity between damselfish species with and without the c-md ligament. Although species lacking the c-md ligament presented a conserved kinematic pattern resulting from high ram and low suction performances, our results did not support an optimization of the ram feeding mode. Indeed, some species with the c-md ligament showed the same or exceeded the ram performance of species without the c-md ligament. The species with the c-md ligament had a more diverse kinematic pattern exploring the entire ram-suction functional range in damselfishes. Finally, our results did not show any diet variations associated with the loss of the c-md ligament. Our study furthers the understanding of how a morphological trait has shaped, by its presence or absence, the ecomorpho-functional diversification of Pomacentridae.
Received: 12 July 2017 / Accepted: 24 September 2017 / Published online: 12 July 2017
Phenotypic influences on the reproductive strategy of the facultative sexual rotifer Brachionus rubens (Monogononta)Download PDFAbstract
Facultative sexual species employ a dual reproductive strategy (heterogony) comprising primarily asexual reproduction with intermittent sexual reproduction. Given the higher relative costs of sexual reproduction, elucidating the triggers underlying these transitions might help our understanding of the evolution of (obligate) sex in general. Existing hypotheses into how and when facultative sexuals invest into sex focus largely either on environmental (habitat-deterioration and resource-demanding hypotheses) or genetic factors (condition-dependent hypothesis), but tend to lack experimental evidence, especially with respect to within-population variation. To address this deficit, we examined the influence of several variables that potentially affect fitness (food quality, water temperature, physiological acclimation, and all combinations thereof) on both the lifetime reproduction (total number of offspring) and investment into sexual offspring per female in a clonal population of the monogonont rotifer Brachionus rubens. Investment into sex, both absolutely and relative to lifetime reproduction, was tied most closely to and positively correlated with individual fitness (i.e., lifetime reproduction): individuals with higher fitness invested more into sexual reproduction. These results run contra to the condition-dependent hypothesis and indicate an energy-budget analogue of the resource-demanding hypothesis. Furthermore, investment into sex increased after a period of physiological acclimation to the new conditions, probably because of the amelioration of short-term stress effects or clonal selection. Our results underscore that life history and general phenotypic considerations—here, energetic provisioning of offspring, the presence of a sexual resting stage, and the relative timing of sexual versus asexual reproduction—can modify existing hypotheses based either on environmental or genetic factors alone.
Received: 23 May 2016 / Accepted: 01 September 2016 / Published online: 23 May 2016
Review of the East African species of the phaneropterine genus Parapyrrhicia Brunner von Wattenwyl, 1891 (Insecta: Orthoptera): secret communication of a forest-bound taxonDownload PDFAbstract
The East African species of Parapyrrhicia Brunner von Wattenwyl, 1891, are reviewed. Beside the description of five new species from the West Usambara, Udzungwa, Uluguru Mountains, and coastal Tanzania and the male of P. zanzibarica Brunner von Wattenwyl, 1891, data on habitat, morphology, acoustics, and the chromosomes are provided. A key to the species of Parapyrrhicia is provided. Eulioptera zanzibarica Brunner von Wattenwyl, 1891, is synonymized with Parapyrrhicia zanzibarica Brunner. All species have stridulatory files with intertooth intervals decreasing from anal to basal and low duty cycle calling songs (four species recorded) consisting of very short, narrow-banded, resonant syllables. Parapyrrhicia species showed a plesiomorphic karyotype with a diploid chromosome number of 2n = 31 and a X0 sex chromosome system in males. All species are restricted to closed wet forest areas and thus ideal organisms to be used for monitoring habitat quality of an area since they act as indicators for indigenous wet forest communities. Morphological sister pairs suggest recent speciation processes in coastal and lowland wet forests of East Africa.
Received: 26 September 2016 / Accepted: 19 December 2016 / Published online: 26 September 2016
A new giant egg-laying onychophoran (Peripatopsidae) reveals evolutionary and biogeographical aspects of Australian velvet wormsDownload PDFAbstract
Representatives of Ooperipatellus (Peripatopsidae) are among the smallest onychophorans known, commonly varying between 10 and 20 mm in length. Herein, we present a peculiar new species of Ooperipatellus from Tasmania that can exceed twice the length of other representatives of this taxon. Ooperipatellus nickmayeri
sp. nov. is comprehensively described based on morphological, molecular, karyological and slime protein profile data. Morphological analyses expose a set of novel features in this species, including a swollen area covered with a modified integument on the posterior border of the male genital pad, modified papillae on the female ovipositor and the presence of pseudoplicae in the dorsal integument. The evolutionary significance of pseudoplicae remains unclear, but similarities between O. nickmayeri
sp. nov. and Plicatoperipatus jamaicensis, the only species from which these structures were previously known, suggest they evolved due to functional constraints of the onychophoran integument. Our karyological investigation further revealed that the new species has the largest karyotype known within Peripatopsidae (2n = 50, XY). Finally, the results of our molecular phylogenetic analyses support the recognition of O. nickmayeri
sp. nov. and shed light on previously unclear aspects of the biogeographical history of Ooperipatellus in Southern Australia, Tasmania and New Zealand.