Received: 05 May 2003 / Accepted: 21 April 2021 / Published online: 05 May 2003
A preliminary phylogeny of Loasaceae subfam. Loasoideae (Angiospermae: Cornales) based on trnL(UAA) sequence data, with consequences for systematics and historical biogeographyDownload PDFAbstract
The phylogeny of Loasaceae subfam. Loasoideae is investigated with sequences of the chloroplast trnL(UAA) intron, all genera and infrageneric entities are included in the analysis. Loasaceae subfam. Loasoideae is monophyletic, and the two most speciose, and monophyletic, clades (which account for approximately 90% of the species total) are Nasa and the so-called Southern Andean Loasas (Blumenbachia, Caiophora, Loasa s.str., Scyphanthus), but the phylogeny of the remainder is not completely resolved. The data underscore a basal position for Chichicaste, Huidobria, Kissenia, and Klaprothieae (Xylopodia, Klaprothia, Plakothira). High bootstrap support values confirm the monophyly both of Klaprothieae and Presliophytum (when expanded to include Loasa ser. Malesherbioideae). Aosa and Blumenbachia are not resolved as monophyletic, but have clear morphological apomorphies. Within Nasa, “N. ser. Saccatae” is paraphyletic, and “N. ser. Carunculatae” is polyphyletic. However, the N. triphylla group in “N. ser. Saccatae” is a well-supported monophyletic group, as is N. ser. Grandiflorae. “Loasa” in its traditional circumscription is paraphyletic, but Loasa s.str. (L. ser. Macrospermae, L. ser. Deserticolae, L. ser. Floribundae) is monophyletic. The remainder of “Loasa” (L. ser. Pinnatae, L. ser. Acaules, L. ser. Volubiles) is probably closely allied to the essentially Patagonian-High Andean group comprising also Scyphanthus and Caiophora. These findings are congruent with morphology and phytogeography. Nasa seems to have undergone its primary radiation at moderate elevations (1500–2500m) in the Andes of northern Peru (Amotape-Huancabamba Zone) and subsequently diversified into high elevations (above 4000m) of the tropical Central Andes. South Andean Loasas appear to have undergone their primary diversification in the southern temperate and mediterranean regions of Chile and Argentina, with a subsequent northwards expansion of Caiophora into the high elevations of the tropical Andes. Hummingbird pollination has evolved independently from melittophily in High Andean clades of Nasa and Caiophora.
Received: 24 March 2003 / Accepted: 21 April 2021 / Published online: 24 March 2003
Comparative study of thoracic structures of adults of Hydrophiloidea and Histeroidea with phylogenetic implications (Coleoptera, Polyphaga)Download PDFAbstract
External and internal structures of adults of Hydrophiloidea and Histeroidea were examined. Skeletal and muscular features of Helophorus aquaticus and Margarinotus brunneus are described in detail. Morphological data are presented as a list of characters and data matrix, and analysed together with other characters of adults, characters of larvae, and characters related to reproduction, habitats and feeding habits. The results of the analysis (characters unweighted) of the full dataset unambiguously support the monophyly of the following clades: [Scarabaeoidea (represented by a genus of Lucanidae and a genus of Scarabaeidae)+Hydrophiloidea+Histeroidea], [Hydrophiloidea+Histeroidea], Histeroidea, [Sphaeritidae+Histeridae], Hydrophiloidea, Hydrophiloidea (excluding Helophoridae), Hydrophiloidea (excluding Helophoridae and Hydrochidae), [Epimetopidae+Georissidae], and [Spercheidae+Hydrophilidae]. The monophyly of all histeroid and hydrophiloid families and of Hydrophilidae (represented by hydrophilines and sphaeridiines) excluding Berosus is also supported. The placement of Scarabaeoidea is in contrast to a taxonomic treatment as a lineage with the same rank as Staphyliniformia. Hydraenidae are not closely related to Hydrophiloidea. The clade comprising Hydrophiloidea and Histeroidea is well supported, but mainly by larval features correlated with predacious habits. The position of Spercheidae implies that a considerable number of seemingly plesiomorphic features of the head are due to reversal and specialized feeding habits (filter feeding). Histeridae show a highly derived pattern of thoracic features with unusual muscular modifications, a long horizontal, dorsal part of the mesopleuron, widely separated metacoxae and a strongly simplified metafurca. Hydrophiloidea are well supported by character transformations of the thorax and other body parts, which are probably related to the invasion of the aquatic habitat in the adult stage, e.g. surface modifications related to the ventral plastron. Georissidae+Epimetopidae are characterized by derived features, which may be the result of a secondarily terrestrial or semiterrestrial life style (partly reduced ventral pubescence), and by a weakly sclerotized mesonotum, mesofurca and metafurca. Hydrochidae, Georissidae and Epimetopidae show a considerable number of autapomorphies, whereas Helophoridae are probably close to the groundplan of Hydrophiloidea. The adaptations to an aquatic life style and the specific habits are very different in Hyrophiloidea and the aquatic groups of Adephaga.
Abstracts of the 7th annual congress of the Gesellschaft für Biologische Systematik (GfBS, Society for Biological Systematics)Download PDF
Received: 27 February 2004 / Accepted: 21 April 2021 / Published online: 27 February 2004
Is Ellipura monophyletic? A combined analysis of basal hexapod relationships with emphasis on the origin of insectsDownload PDFAbstract
Hexapoda includes 33 commonly recognized orders, most of them insects. Ongoing controversy concerns the grouping of Protura and Collembola as a taxon Ellipura, the monophyly of Diplura, a single or multiple origins of entognathy, and the monophyly or paraphyly of the silverfish (Lepidotrichidae and Zygentoma s.s.) with respect to other dicondylous insects. Here we analyze relationships among basal hexapod orders via a cladistic analysis of sequence data for five molecular markers and 189 morphological characters in a simultaneous analysis framework using myriapod and crustacean outgroups. Using a sensitivity analysis approach and testing for stability, the most congruent parameters resolve Tricholepidion as sister group to the remaining Dicondylia, whereas most suboptimal parameter sets group Tricholepidion with Zygentoma. Stable hypotheses include the monophyly of Diplura, and a sister group relationship between Diplura and Protura, contradicting the Ellipura hypothesis. Hexapod monophyly is contradicted by an alliance between Collembola, Crustacea and Ectognatha (i.e., exclusive of Diplura and Protura) in molecular and combined analyses.
Received: 05 April 2004 / Accepted: 21 April 2021 / Published online: 05 April 2004
Radiation and adaptation, evolutionary biology and semanticsDownload PDFAbstract
Radiations can be either adaptive or non-adaptive, resulting in a variety of niches occupied by sympatric species, or in hardly any niche differentiation and species showing largely mosaic distribution patterns. The terms are useful despite the fact that intermediate situations occur.
Received: 12 July 2003 / Accepted: 21 April 2021 / Published online: 12 July 2003
Adaptive radiation in sauropod dinosaurs: bone histology indicates rapid evolution of giant body size through accelerationDownload PDFAbstract
The well-preserved histology of the geologically oldest sauropod dinosaur from the Late Triassic allows new insights into the timing and mechanism of the evolution of the gigantic body size of the sauropod dinosaurs. The oldest sauropods were already very large and show the same long-bone histology, laminar fibro-lamellar bone lacking growth marks, as the well-known Jurassic sauropods. This bone histology is unequivocal evidence for very fast growth. Our histologic study of growth series of the Norian Plateosaurus indicates that the sauropod sistergroup, the Late Triassic and early Jurassic Prosauropoda, reached a much more modest body size in a not much shorter ontogeny. Increase in growth rate compared to the ancestor (acceleration) is thus the underlying process in the phylogenetic size increase of sauropods. Compared to all other dinosaur lineages, sauropods were not only much larger but evolved very large body size much faster. The prerequisite for this increase in growth rate must have been a considerable increase in metabolic rate, and we speculate that a bird-like lung was important in this regard.
Received: 01 August 2003 / Accepted: 21 April 2021 / Published online: 01 August 2003
Aquatic amphipods (Crustacea: Amphipoda: Crangonyctidae) in three pieces of Baltic amberDownload PDFAbstract
Three amber pieces containing crangonyctid aquatic amphipods are examined. One of the specimens appears to have the urosome unsegmented, and uropods 3 shortened, resembling extant Synurella sp. In another amber piece there are eight specimens of Palaeogammarus sp. which look as if they had been dry prior to becoming embedded in the resin.
Received: 23 October 2003 / Accepted: 21 April 2021 / Published online: 23 October 2003
The radiation of the Seicercus burkii complex and its congeners (Aves: Sylviidae): molecular genetics and bioacousticsDownload PDFAbstract
Cryptic species of passerine birds lack notable morphological differentiation and can best be identified by molecular and bioacoustic markers. Here we investigate seven cryptic species of the golden-spectacled warbler (Seicercus burkii complex) with respect to territorial song and cytochrome-b (cyt-b) sequences. Their phylogenetic relations to other Seicercus species and to members of the genus Phylloscopus are inferred by the same methods. Three separate lineages of Seicercus are nested within different branches of the molecular Phylloscopus tree. The S. burkii complex is a monophyletic unit comprising seven species (S. burkii s. str., S. whistleri, S. valentini, S. soror, S. omeiensis, S. tephrocephalus and S. affinis). S. xanthoschistos turned out to be a close relative of Phylloscopus davisoni within the P. reguloides group. Two isolated sister taxa, S. grammiceps and S. castaniceps, also branch together with the P. reguloides group. Within the S. burkii complex the overall haplotype and nucleotide diversity is highest in taxa from the Chinese middle and upper mountain belt (S. valentini, S. omeiensis and S. soror), indicating at least partially restricted gene flow in these species. This is explained by the fragmentation of high-altitude habitats in China while in the Himalayas the vicariant species S. whistleri inhabits a more continuous mountain belt at the same altitude. For the Chinese species from medium and high altitudes, past range expansion is indicated by significantly negative Tajima Ds. According to pairwise genetic distances, most species of the S. burkii complex have diverged 5myr ago, the most recent split between S. burkii and S. tephrocephalus is dated 2myr ago. Coalescence times for haplotype lineages of the different species range from 9 up to 12myr, and between 5 and 6myr for S. burkii and S. tephrocephalus.Within Seicercus divergence of song features such as frequency parameters and syntax structures correlate with genetic distances between taxa. The three cyt-b lineages of Seicercus correspond to different clusters in a discriminant analysis by acoustic parameters. Common syntax structures of territorial song in the Phylloscopus/Seicercus assemblage are: (1) an introductory element derived from specific calls and (2) a syntax of trills and repeated element groups or a combination of both. There are clear indications that these song structures have repeatedly emerged, were lost or were altered in different branches of the phylogenetic tree at different times. Absolute differences between taxa in frequency parameters or in an acoustic divergence index increase significantly with growing genetic distances. However, due to multiple parallel evolution phylogenetic information provided by single acoustic traits decreases with increasing numbers of taxa involved in the investigation.
Received: 23 June 2003 / Accepted: 21 April 2021 / Published online: 23 June 2003
Description of two new species of Bodinia, a new genus incertae sedis in Argestidae Por, 1986 (Copepoda, Harpacticoida), with reflections on argestid colonization of the Great Meteor Seamount plateauDownload PDFAbstract
The present paper focuses on the results of taxonomic, faunistic and chorologic investigations on Argestidae Por, 1986 (Copepoda, Harpacticoida). All argestid species collected during the cruise M42/3 of RV “Meteor” (1998) are new to science. In the present contribution, two species are described and united within Bodinia gen. nov.: Bodinia meteorensis sp. nov. and Bodinia peterrummi sp. nov. The new genus is placed as incertae sedis in Argestidae in light of uncertainty concerning the phylogenetic relations within this group and even its status as a monophylum. The question is discussed how members of Argestidae, previously seen as a deep-sea taxon, may have colonized the shallow-water habitat of the Great Meteor Seamount plateau.
Received: 18 December 2003 / Accepted: 21 April 2021 / Published online: 18 December 2003
Ideal phenotypes and mismatching haplotypes – errors of mtDNA treeing in ants (Hymenoptera: Formicidae) detected by standardized morphometryDownload PDFAbstract
A total of 401 nest samples of Formica lugubris Zetterstedt, F. pratensis Retzius, F. aquilonia Yarrow, F. rufa Linnaeus, and F. polyctena Förster, covering the entire Palaearctic range of these species and including 2100 individual workers, was phenotypically investigated by a system of standardized morphometry, pairwise removal of allometric variance, and canonical discriminant functions. A mitochondrial DNA fragment including the cytochrome b gene was sequenced in 148 samples from basically the same range. In the more difficult F. pratensis vs. F. lugubris case, the phenotypic system correctly determined 99.6% of all nest samples, and 95.1% with p<0.05. In all other pairwise species discriminations any nest sample was correctly determined with p<0.01, and three samples with hybrids F. rufa×lugubris were identified. At four localities in the Pyrenees and the Urals, 9 samples with F. pratensis phenotypes (7 of them ideal) but F. lugubris mtDNA haplotypes could be identified, resulting in 14.5% of phenotype/haplotype mismatches. A local dominance of this mismatch combination was observed at one Pyrenean and one Ural locality. There was no indication of an F. pratensis haplotype associated with an F. lugubris phenotype. One ideal F. polyctena phenotype was associated with an F. aquilonia haplotype in a sample from the Urals, and one ideal F. aquilonia phenotype was combined with an F. lugubris haplotype in a sample from central Siberia, resulting in overall phenotype/haplotype mismatch frequencies of 12.5% and 11.1%, respectively. We conclude that all these samples cannot represent actual F1 hybrids but are the result of hybridizations in the past followed by unidirectional purging of the nuclear genome. Whether this process of purging worked very fast or over longer periods of population history, and whether or not it was complete or incomplete, cannot be assessed from the available information. These facts of hybridizing in two thirds of the W Palaearctic wood ant species, of extreme regional hybrid frequencies (up to 26%), of unidirectional purging of nDNA associated with mismatching mtDNA haplotypes, and of occasional achievement of local dominance of these mismatch combinations, may serve as urgent warning not to perform isolated mtDNA phylogenetic studies without a geographically and locally wide sampling basis and without control by nDNA information or reliable phenotypic determination. The latter two systems definitely have superior significance when conflicts with mtDNA indications arise.
Received: 20 May 2003 / Accepted: 21 April 2021 / Published online: 20 May 2003
Earthworms (Clitellata, Acanthodrilidae) of the mountains of Eastern JamaicaDownload PDFAbstract
Fourteen species new to science are described from material collected at several sites in the Blue Mountains and the John Crow Mountains of eastern Jamaica, doubling the known endemic Jamaican earthworm fauna. New data on Dichogaster montecyanensis (Sims) are provided. All species are placed in the genus Dichogaster Beddard, which is here treated sensu lato, i.e. including Eutrigaster Cognetti. Eight of the new species have lost the posterior pair of prostates and the seminal grooves of the male field. These are D. bromeliocola, D. crossleyi, D. davidi, D. garciai, D. harperi, D. haruvi, D. hendrixi, and D. johnsoni. D. sydneyi n. sp. has independently lost the posterior prostates but not the seminal grooves. The new species D. altissima and D. manleyi have the conventional dichogastrine prostatic battery and male field characteristics. Three species described here, D. farri, D. garrawayi, and D. marleyi, all have a third pair of prostates in the 20th segment, no seminal grooves, dorsal paired intestinal caeca in segment lxv, and lack penial setae.
The 44th Phylogenetisches Symposium - Bonn, 22-24 November 2002 - on ‘adaptive radiation’Download PDF
Received: 30 April 2003 / Accepted: 21 April 2021 / Published online: 30 April 2003
Potential key characters in Opisthobranchia (Gastropoda, Mollusca) enhancing adaptive radiationDownload PDFAbstract
Five potential key characters which might have enhanced species radiation in the Opisthobranchia (Gastropoda) are discussed. These are: 3–4 cuticular plates in the gizzard of Cephalaspidea s.str., kleptoplasty in Sacoglossa, kleptocnides in Aeolidoidea, a symbiotic relationship with unicellular algae in Phyllodesmium Ehrenberg, 1831, and mantle dermal formations in Chromodorididae. Interpretation of the characters as key innovations is based on phylogeny and/or comparison of species numbers in subgroups. Possible adaptive zones are discussed, and alternative interpretations indicated.
Received: 16 December 2003 / Accepted: 21 April 2021 / Published online: 16 December 2003
Mitochondrial phylogeography of the Dalmatian wall lizard, Podarcis melisellensis (Lacertidae)Download PDFAbstract
A 903bp section of the mitochondrial cytochrome b gene was sequenced from 73 specimens of Podarcis melisellensis collected at 52 localities distributed over the major part of the species’ range. In addition, parts of the 12S (about 470bp) and 16S rRNA (about 500bp) genes were analysed for 11 representative samples leading to a congruent phylogeny. Our study includes representatives of all 20 subspecies recognized today. The phylogenetic analysis of the sequence data revealed three main clades: mainland with nearby islands, Vis archipelago, and Lastovo archipelago. The degree of mitochondrial DNA divergence among these clades suggests a separation of the respective population groups during the earliest Pleistocene. The phylogenetic pattern observed within the species is in sharp contrast to the actual taxonomic division into subspecies. A correlation between genetic diversity of P. melisellensis populations and paleogeography of the regions they inhabit is discussed.
Received: 16 July 2003 / Accepted: 21 April 2021 / Published online: 16 July 2003
Adaptive radiation and coevolution — pollination biology case studiesDownload PDFAbstract
The impact of coevolutionary interaction between species on adaptive radiation processes is analysed with reference to pollination biology case studies. Occasional colonization of archipelagos can bring together coevolving partners and cause coradiation of the colonizing species, e.g. the drepanidids and the lobelioids on Hawaii. Permanent reciprocal selective pressure between pairs of coevolving species can lead to a coevolutionary race and rapid evolutionary change. This is exemplified by spurred flowers and long-tongued flower-visitors. The geographic patterning of diffuse coevolution systems can lead to dramatic changes in species interactions. In different populations, interaction between pollinating and seed-parasitizing Greya moths and their host plants varies from mutualism to commensalism and antagonism, depending on the presence of copollinators. Asymmetrical coevolution between angiosperms and oligolectic flower-visitors may facilitate rapid reproductive isolation of populations following a food-plant switch, if the oligoleges use their specific food plants as the rendezvous sites. Diffuse coevolution between angiosperm species and pollinating insects may cause frequent convergent evolution of floral traits such as nectar reward instead of pollen reward, floral guides, zygomorphic flowers, or mimicry of pollen signals, since the multiple plant species experience similar selective pressures via the coevolving partners. Patterns of angiosperm adaptive radiation are highlighted in the context of coevolution with pollinators.
Received: 01 October 2003 / Accepted: 21 April 2021 / Published online: 01 October 2003
Morphogenesis of the reproductive shoots of Welwitschia mirabilis and Ephedra distachya (Gnetales), and its evolutionary implicationsDownload PDFAbstract
For decades, Gnetales appeared to be closely related to angiosperms, the two groups together forming the anthophyte clade. At present, molecular studies negate such a relationship and give strong support for a systematic position of Gnetales within or near conifers. However, previous interpretations of the male sporangiophores of Gnetales as pinnate with terminal synangia conflict with a close relationship between Gnetales and conifers. Therefore, we investigated the morphogenesis of the male reproductive structures of Welwitschia mirabilis and Ephedra distachya by SEM and light microscopy. The occurrence of reduced apices to both halves of the antherophores of W. mirabilis gives strong support for the assumption that the male ‘flowers’ of W. mirabilis represent reduced compound cones. We assume that each half of the antherophore represents a lateral male cone that has lost its subtending bract. Although both halves of the antherophores of Ephedra distachya lack apical meristems, the histological pattern of the developing antherophores supports interpreting them as reduced lateral male cones as well. Therefore, the male sporangiophores of Gnetales represent simple organs with terminal synangia. Although extant conifers do not exhibit terminal synangia, similar sporangiophores are reported for some Cordaitales, the hypothetical sister group of conifers. Moreover, several Paleozoic conifers exhibit male cones with terminal sporangia or synangia. Therefore, we propose that conifers, Cordaitales and Gnetales originated from a common ancestor that displayed simple sporangiophores with a terminal cluster of sporangia.
Received: 27 November 2003 / Accepted: 21 April 2021 / Published online: 27 November 2003
nrDNA internal transcribed spacer data reveal that Rhodoplagiochila R.M. Schust. (Marchantiophyta: Jungermanniales) is a member of Plagiochila sect. Arrectae CarlDownload PDFAbstract
The monospecific genus Rhodoplagiochila, previously known only from the type collected in the Venezuelan Andes, has been collected at a second site close to the type locality. Up to now, generic status of Rhodoplagiochila has been accepted by most authors, but the taxon had been alternately assigned to Plagiochilaceae or Lophoziaceae. Phylogenetic analyses of nrITS sequences from Rhodoplagiochila and other representatives of the Plagiochilaceae clearly reveal the former to be in a clade with members of the Neotropical–Atlantic European Plagiochila sect. Arrectae. Within the Arrectae, Rhodoplagiochila is positioned in a robust clade made up of several accessions of Plagiochila bifaria. Morphologically, Rhodoplagiochila differs from other phenotypes of P. bifaria by the papillose leaf surface and a leaf margin which is ciliately toothed all-around. As an outcome of the molecular and morphological investigations, Rhodoplagiochila rosea is treated as a variety of P. bifaria, and the new combination P. bifaria var. rosea comb. et stat. nov. is proposed. In tropical America the family Plagiochilaceae seems to be represented only by Plagiochila.
Received: 31 January 2004 / Accepted: 21 April 2021 / Published online: 31 January 2004
Redescription of three species of Haploniscus Richardson, 1908 (Isopoda, Asellota, Haploniscidae) from the Angola BasinDownload PDFAbstract
Based on material from the deep sea of the Angola Basin (South Atlantic Ocean), new diagnoses are provided for the genus Haploniscus Richardson, 1908 and the species H. bicuspis (Sars, 1877), H. spinifer Hansen, 1916, and H. nondescriptus Menzies, 1962. Full redescriptions, including previously undescribed details, and a discussion of phylogenetic status are given in an electronic supplement.
Received: 08 March 2004 / Accepted: 21 April 2021 / Published online: 08 March 2004
Radiation within the framework of evolutionary ecologyDownload PDFAbstract
The talks and extensive discussions on ‘adaptive radiation’ during the phylogenetic symposium 2002 in Bonn are summarized, and concluding remarks presented from the perspective of evolutionary ecology. Radiation is characterized as the relatively rapid origin of diverse ecological niches established by repeated speciation events within a lineage, leading to stronger evolutionary divergence and ecological diversity in a particular region. Rather than simply being multiple speciation events resulting in the formation of a monophylum, it is a concept to understand ecological divergence and biodiversity, which emphasizes diversification of ecologically relevant morphology, physiology and behaviour of the descendants of a stem species. Therefore, instead of ‘adaptive radiation’ it is better termed ‘ecological radiation’ or simply ‘radiation’.A radiation starts with the splitting of the stem species into different lineages, and ends when either a new radiation occurs within that monophylum or the monophylum becomes extinct. This leads to a hierarchical sequence of radiations, here exemplified from the phylogeny of Insecta. Three types can be distinguished: radiation after successful colonization, radiation from a survivor of mass extinctions, and radiation after evolution of key innovations. In the first two scenarios, chance is more important and the founders of a radiation might be relatively unspecialized; in the third case, the founders are more specialized and exhibit several novelties accumulated in the ancestral line. As key innovations, the role of these features is to help open a new ecozone and to recruit new resources, which is initiated by changes in behaviour or metabolic traits.Key characters can be used under diverse ecological conditions and modes of life, and allow the establishment of various econiches. An analysis starts with the reconstruction of a phylogenetic tree based on all known characters and the reconstruction of the ‘stem species pattern’, followed by an analysis of transformations of functional structures to find possible key innovations. The investigation of at least nine additional points is desirable to understand radiation and thus explain diversity.
Received: 15 July 2003 / Accepted: 21 April 2021 / Published online: 15 July 2003
Adaptive, pre-adaptive and non-adaptive components of radiations in ancient lakes: a reviewDownload PDFAbstract
Ancient lakes are ideal model systems for evolutionary studies, as they hold hundreds of endemic species. The vast majority of these still occur in the cradle of their origin. We distinguish three different modes of speciation (allo-, para- and sympatric) which have occurred in these habitats. Although radiations from ancient lakes are generally assumed to be adaptive, we cannot fully support this point of view, because non-adaptive radiations also appear to be common, for example through chromosomal changes, hybridization or sexual selection. Even in supposedly adaptive cladogenesis, e.g. as concerns the presumed trophic adaptations of cichlid (Pisces) mouth and tooth shapes, both adaptive and non-adaptive components are acting. Distribution patterns of non-marine ostracods (Crustacea) within and outside of ancient lakes indicate that sexual reproduction might be an additional requirement for successful radiations in ancient lakes, at least in certain groups. This can best be understood by invoking ecology-based hypotheses on the evolutionary superiority of sexual reproduction such as Fisher–Muller accelerated evolution and the Tangled Bank.
Received: 30 May 2003 / Accepted: 21 April 2021 / Published online: 30 May 2003
Complex male genitalia (hemispermatophores) are not diagnostic for cryptic species in the genus Euscorpius (Scorpiones: Euscorpiidae)Download PDFAbstract
Genital morphology is often used as a key character for distinguishing species in many arthropod groups. Regarding scorpions, male genitalia (hemispermatophores) have been increasingly used in species descriptions. In the present study we analyse hemispermatophores of four Central European species of Euscorpius Thorell, 1876, and those of Euscorpius flavicaudis (De Geer, 1778) from southern France. The main focus are the three morphologically cryptic species, Euscorpius alpha Caporiacco, 1950, Euscorpius germanus (C.L. Koch, 1837), and Euscorpius gamma Caporiacco, 1950. The clear, deep split between E. alpha and E. germanus previously shown from nuclear allozyme data and mitochondrial genetic markers is not found in hemispermatophore and other morphological characters. Even the hemispermatophore of E. gamma—a species branching off at the same genetic distance level as E. alpha and E. germanus, and clearly diagnosable on external morphological characters—is indistinguishable from those of E. alpha and E. germanus. Although hemispermatophores are complex, they are not more informative than other morphological characters. Euscorpius hemispermatophores may be useful for species discrimination, but in closely related species they are of limited taxonomic value.
Received: 05 June 2003 / Accepted: 21 April 2021 / Published online: 05 June 2003
Phylogenetic relationships in the Lejeuneaceae (Hepaticae) inferred using ITS sequences of nuclear ribosomal DNADownload PDFAbstract
Sequences of the ITS1–5.8S–ITS2 region of nuclear ribosomal DNA were generated for 12 species from 9 genera of Lejeuneaceae and a single species of Jubulaceae (outgroup). The taxon sampling of Lejeuneaceae included representatives of the two widely recognized subfamilies, Lejeuneoideae and Ptychanthoideae. The molecular dataset was analysed independently and in combination with a morphological dataset. The nrITS dataset and the combined dataset resulted in identical topologies. The genus Bryopteris, sometimes treated as a separate family Bryopteridaceae, is nested within the Lejeuneaceae subfamily Ptychanthoideae. Lejeuneaceae subfamily Lejeuneoideae proved to be paraphyletic with the tribe Lejeuneeae sister to Ptychanthoideae, albeit without significant bootstrap support. The tribes Brachiolejeuneeae and Cheilolejeuneeae of Lejeuneoideae, established recently based on morphological evidence, are well supported in bootstrap analyses both of the ITS and the combined molecular–morphological datasets. The results support classifications of Lejeuneaceae based on morphological data and demonstrate the usefulness of the ITS region for phylogenetic studies within or among closely related genera of Lejeuneaceae.
Received: 12 July 2003 / Accepted: 21 April 2021 / Published online: 12 July 2003
Modeling a version of the good-genes hypothesis: female choice of locally adapted malesDownload PDFAbstract
In addition to other potential causes, immigration into locally adapted populations has been suggested to maintain the genetic variance in fitness that is necessary for the good-genes hypothesis. Using population-genetic simulations, the present contribution shows that co-occurring local adaptation and migration can maintain genetic variance in fitness. In combination with an effect of local adaptation on condition and condition-dependent sexual signaling, such a scenario therefore enables the evolution and maintenance of female choice for locally adapted males. The simulations show that this mechanism can also work when choice is costly, and that the potential benefit is similar to that in other good-genes mechanisms. As a consequence of female choice in favor of locally adapted males, differentiation between populations can be expected to increase due to the decreased effective gene flow between populations. Based on such effects, choice of locally adapted males has the potential to play an important role in speciation and adaptive radiation.
Received: 02 September 2003 / Accepted: 21 April 2021 / Published online: 02 September 2003
The information content of an ambiguously alignable region, a case study of the trnL intron from the RhamnaceaeDownload PDFAbstract
An earlier analysis of the trnL intron in the Colletieae (Rhamnaceae) showed polyphyly of the genus Discaria. Polyphyly of Discaria is supported only by an AT-rich region of ambiguous alignment within the trnL intron. Polyphyly of the genus relies on extracting the information of the AT-rich region correctly. Ambiguously aligned regions are commonly excluded from phylogenetic analysis. In the present study the question was raised whether random or noisy data could generate a pattern like the one found in the AT-rich region of ambiguous alignment. The original pattern was resistant to changes in alignment parameter cost when submitted to a sensitivity analysis using direct optimization. Artificially generated random or noisy data gave well-resolved trees but these were found to be extremely sensitive to changes in parameter costs. However, information from additional data, such as conserved regions, restricts the influence of random data. It is here suggested that the information in ambiguously aligned regions need not be dismissed, provided that an appropriate method that finds all possible optimal alignments is used to extract the information. In addition to commonly used support measures, some information of robustness to changes in alignment parameter costs is needed in order to make the most reliable conclusions.
Received: 23 February 2004 / Accepted: 21 April 2021 / Published online: 23 February 2004
Vanhoeffenura nom. nov. replaces Vanhoeffenella Malyutina, 2003 (Crustacea: Isopoda: Asellota)Download PDFAbstract
The isopod genus name Vanhoeffenella Malyutina, 2003 is a junior homonym of Vanhoeffenella Rhumbler, 1905, a genus group name in Foraminifera. Therefore, Vanhoeffenella Malyutina is replaced with Vanhoeffenura nom. nov.
Received: 21 November 2003 / Accepted: 21 April 2021 / Published online: 21 November 2003
Baltic amber fossils reveal early evolution of sexual dimorphism in stalk-eyed flies (Diptera: Diopsidae)Download PDFAbstract
A cladistic analysis of 16 species of extant and amber fossil stalk-eyed flies of the family Diopsidae places the fossil †Prosphyracephala succini (Loew) as the sister group of all other Diopsinae, the subfamily in which eye stalks occur. The study is based on a scoring including five old and 23 new finds of †P. succini from Baltic amber, and for the first time allows a morphometric analysis of eye span and various body size parameters in this species. The data indicate that sexual dimorphism of the eye stalks already existed in †Prosphyracephala, suggesting that this feature evolved early in the Diopsinae. Contrary to recent views that the ancestral condition of diopsine eye stalks was monomorphic, the new results suggest that sexual selection was involved in the evolution of eye stalks from the very beginning of the lineage.
Received: 21 July 2003 / Accepted: 21 April 2021 / Published online: 21 July 2003
The staminal lever mechanism in Salvia L. (Lamiaceae): a key innovation for adaptive radiation?Download PDFAbstract
Floral key innovations play a significant role in the discussion of adaptive radiation in plants. The paper brings together a brief review of morphological key innovations in plants, elucidating their evolutionary significance in flower–pollinator interactions, and new data on Salvia, a genus being examined as an example for presumed adaptive radiation. We hypothesize that the characteristic staminal lever mechanism functions as a key innovation. It is defined as a functional unit including the modification of stamens to lever-like structures, their reversible movement, and the organization of the remaining floral structures involved in the process of pollen transfer. We follow the assumption that structure and functioning of the staminal levers play a major role in the process of pollen deposition on the pollinator's body, and that minute changes of both their proportions and their interactions with pollinators may have significant consequences for the pollination system. The functioning of the staminal lever mechanism is tested by field investigations, biomechanical experiments and pollination simulations. First results are presented, and possible modes of allopatric and sympatric speciation are discussed, based on morphometry of Salvia flowers and pollinators as well as on the operating mode of the staminal lever mechanism. Special attention is given to species-specific patterns of pollen deposition on the pollinator's body. We assume that, depending on the precision of the lever movement, sympatric Salvia species flowering during overlapping periods and sharing the same pollinating species may be either mechanically isolated from each other or able to hybridize. The latter may result in speciation, as may spontaneous mutations influencing the flower-pollinator interaction, e.g. by significant changes in morphometry of the staminal lever system and/or other flower structures. As a consequence, Salvia individuals may deposit pollen on a different part of the pollinator's body, or even adapt to a new pollinator species, both resulting in reproductive isolation from the parental population.
Received: 31 October 2003 / Accepted: 21 April 2021 / Published online: 31 October 2003
Phylogenetic relationships of African microhylid frogs inferred from DNA sequences of mitochondrial 12S and 16S rRNA genesDownload PDFAbstract
The phylogenetic relationships of microhylid frogs are poorly understood. The first molecular phylogeny for continental African microhylids is presented, including representatives of all subfamilies, six of the eight genera, and the enigmatic hemisotid Hemisus. Mitochondrial 12S and 16S rRNA sequence data were analysed using parsimony, likelihood and Bayesian methods. Analyses of the data are consistent with the monophyly of all sampled subfamilies and genera. Hemisus does not nest within either brevicipitines or non-brevicipitines. It is possibly the sister group to brevicipitines, in which case brevicipitines might not be microhylids. Phrynomantis and Hoplophryne potentially group with non-African, non-brevicipitine microhylids, in agreement with recent morphological and molecular data. Within brevicipitines, Breviceps is recovered as the sister group to a clade of Callulina+Spelaeophryne+Probreviceps. The relationships among the genera within this latter clade are unclear, being sensitive to the method of analysis. Optimal trees suggest the Probreviceps macrodactylus subspecies complex might be paraphyletic with respect to P. uluguruensis, corroborating preliminary morphological studies indicating that P. m. rungwensis may be a distinct species. P. m. loveridgei may be paraphyletic with respect to P. m. macrodactylus, though this is not strongly supported. Some biogeographic hypotheses are examined in light of these findings.