Phylogenetic relationships of the pygmy rice rats of the genus Oligoryzomys Bangs, 1900 (Rodentia: Sigmodontinae)

Sequences from two mitochondrial genes (cytochrome b and NADH1) were used to produce a molecular phylogeny for 12 named and two undescribed species of the genus Oligoryzomys. All analyses placed Oligoryzomys microtis as the most basal taxon, a finding consistent with previous studies that suggested the west‐central Amazon as a centre of origin for the tribe Oryzomyini to which Oligoryzomys belongs. Biogeographically, this suggests that Oligoryzomys had a South American origin, and later advanced northwards, entering Central America and Mexico more recently. Different analyses have provided consistent support for several additional clades that did not necessarily agree with the species groups hypothesized by previous studies. A molecular clock derived for these data suggests an origin for the genus of 6.67 Mya, with most speciation within the genus occurring between 3.7 and 1.5 Mya. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 551–566.     

Holarctic phylogeography of the tundra shrew (Sorex tundrensis) based on mitochondrial genes

A range‐wide phylogeographic study of the tundra shrew (Sorex tundrensis) was performed using cytochrome b and cytochrome oxidase I (COI) mitochondrial genes. The results based on 121 specimens from 42 localities demonstrate that the tundra shrew is divided into five main mitochondrial DNA phylogenetic lineages with largely parapatric distribution. In addition to a single Nearctic clade (Alaska) four Palearctic clades are identified: Western (Northen Urals, Kazakhstan, South‐West Siberia), Eastern (from East Transbaikalia and the Middle Amur to Chukotka), South Central (Central Siberia, the Altai, the Dzhungarian Alatau) and North Central (Northern Siberia, Central Yakutia). Date estimates obtained by use of a molecular clock corrected for potential rate decay suggest Late Pleistocene age for the most recent common ancestor of all contemporary tundra shrew populations. Relatively high genetic divergence between phylogroups (0.95–1.6%) indicates that the observed phylogeographic structure was initiated by historical events that predated the Last Glacial Maximum. We assume that, being more cold‐ and arid‐tolerant, tundra shrew underwent expansion during an early cold phase of the Last Glacial and spread through its recent range earlier than most of other Siberian red‐toothed shrews. Comparative phylogeographic analysis of Siberian shrews and rodents suggests that evolutionary histories of species associated with azonal or open habitats show important differences compared to forest species. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 721–746.     

The flightless marine midge Pontomyia (Diptera: Chironomidae): ecology,distribution, and molecular phylogeny

Pontomyia Edwards, 1926 (Diptera: Chironomidae) is a genus of exclusively marine flightless midges. There are four described species from the Indo‐Pacific, and one undescribed species known only from females, pupal skins, and larvae from the Atlantic/Caribbean. They are poorly known owing to their small size (～1.0 mm), extremely short adult life (< 3 h), and unusual habitat for an insect (coastal lagoons, bays, or rock pools). We reviewed scattered literature on their biology and systematics, presented photomicrographs of the male hypogium, and updated the geographic distribution of each species. We carried out the first molecular study to elucidate relationships among and within three of the species. Results from our four‐gene phylogenetic reconstruction using combined gene tree and species tree approaches showed that Pontomyia natans, Pontomyia oceana, and Pontomyia pacifica are each well‐supported clades, with P. natans as sister to P. oceana + P. pacifica. Genetic distances based on mitochondrial cytochrome oxidase I are extraordinarily large within P. natans and P. pacifica, which suggests that they may be cryptic species complexes. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 162 , 443–456.     

Molecular and morphological evidence supports the species status of the Mahachai fighter Betta sp. Mahachai and reveals new species of Betta from Thailand

Two regions of mitochondrial (mt) DNA, cytochrome c oxidase subunit 1 (COI) and 16S rRNA, were sequenced in nine species of Betta from Thailand and Indonesia. Most species showed little intraspecific COI variation (adjusted mean = 0·48%) including the putative species Betta sp. Mahachai, but one species (Betta smaragdina) included three lineages showing much greater divergence (7·03–13·48%) that probably represent overlooked species. These findings were confirmed by maximum likelihood analysis and Bayesian inference, which revealed well‐supported corresponding monophyletic clades. Based on these results and morphological differences, the putative species Betta sp. Mahachai from central Thailand is a species distinct from other members of the B. splendens group and represents a new and hitherto undescribed species. Furthermore, this study also demonstrated the probable existence of two overlooked Betta species found in the Khorat plateau basin, illustrating the utility of mitochondrial genetic markers in the revelation of overlooked diversity.     

Endemic evolutionary radiation of Rhagada land snails (Pulmonata: Camaenidae) in a continental archipelago in northern Western Australia

In the Dampier Archipelago of Western Australia's Pilbara Region, several locally endemic, morphologically distinctive species of Rhagada land snails occur, contrasting with the morphologically conservative species with wider distributions on the adjacent mainland. To test alternative origins of this unusual local diversity in a continental archipelago, we examined sequences of the cytochrome oxidase subunit 1 and 16S mitochondrial genes in 22 described species and eight undescribed forms, including all known morphospecies from the Pilbara Region's Dampier Archipelago and adjacent mainland. Phylogenetic analyses consistently resolved four, deep clades within the Pilbara Region, with a mean sequence divergence of 15–18%. All but one of the species from the Dampier Archipelago formed one of the major clades, indicating that the morphological radiation in the archipelago evolved locally, rather than through multiple, relictual mainland lineages. Morphological divergence spanning almost that of the entire genus was within a subclade with sequence divergence < 4%, highlighting the disconnection between morphological diversification and levels of molecular genetic divergence. This in situ morphological radiation in the Dampier Archipelago, which transcends variation seen over much larger distances on the mainland, is unusual for a continental archipelago, and may relate to local heterogeneity of land forms. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 316–327.     

The role of vicariance and dispersal on New Zealand's estuarine biodiversity: the case of Paracorophium (Crustacea: Amphipoda)

To investigate the role of vicariance and dispersal on New Zealand's estuarine biodiversity, we examined variability in mitochondrial cytochrome c oxidase subunit I (COI) gene sequences for the amphipod genus Paracorophium. Individuals from the two nominate endemic species (Paracorophium excavatum and Paracorophium lucasi) were collected from sites throughout the North and South Islands. Sequence divergences of 12.8% were detected among the species. However, divergences of up to 11.7% were also observed between well supported clades, suggesting the possibility of cryptic species. Nested clade analyses identified four distinct lineages from within both P. excavatum and P. lucasi, with boundaries between clades corresponding to topographical features (e.g. Cook Straight, North and East Cape). Sequence divergences of 3.7–4.9% were also observed within geographic regions (e.g. east and west coasts of the upper North Island). Genetic structure in Paracorophium appears to represent prolonged isolation and allopatric evolutionary processes dating back to the Upper Miocene and continuing through the Pliocene and early Pleistocene. On the basis of molecular clock estimates from sequence divergences and reconstructions of New Zealand's geological past, we suggest that sea level and landmass changes during the early Pleistocene (2 Mya) resulted in the isolation of previously contiguous populations leading to the present‐day patterns. COI genetic structure was largely congruent with previously observed allozyme patterns and highlights the utility of COI as an appropriate marker for phylogeographic studies of the New Zealand estuarine fauna. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 863–874.     

Phylogenetic relationships and historical biogeography of tribes and genera in the subfamily Nymphalinae (Lepidoptera: Nymphalidae)

We infer for the first time the phylogenetic relationships of genera and tribes in the ecologically and evolutionarily well‐studied subfamily Nymphalinae using DNA sequence data from three genes: 1450 bp of cytochrome oxidase subunit I (COI) (in the mitochondrial genome), 1077 bp of elongation factor 1‐alpha (EF1‐α) and 400–403 bp of wingless (both in the nuclear genome). We explore the influence of each gene region on the support given to each node of the most parsimonious tree derived from a combined analysis of all three genes using Partitioned Bremer Support. We also explore the influence of assuming equal weights for all characters in the combined analysis by investigating the stability of clades to different transition/transversion weighting schemes. We find many strongly supported and stable clades in the Nymphalinae. We are also able to identify ‘rogue’ taxa whose positions are weakly supported (the different gene regions are in conflict with each other) and unstable. Our main conclusions are: (1) the tribe Coeini as currently constituted is untenable, and Smyrna, Colobura and Tigridia are part of Nymphalini; (2) ‘Kallimini’ is paraphyletic with regard to Melitaeini and should be split into three tribes: Kallimini s.s., Junoniini and Victorinini; (3) Junoniini, Victorinini, Melitaeini and the newly circumscribed Nymphalini are strongly supported monophyletic groups, and (4) Precis and Junonia are not synonymous or even sister groups. The species Junonia coenia, a model system in developmental biology, clearly belongs in the genus Junonia. A dispersal‐vicariance analysis suggests that dispersal has had a major effect on the distributions of extant species, and three biotic regions are identified as being centres of diversification of three major clades: the Palaearctic for the Nymphalis‐group, the Afrotropics for Junoniini and the Nearctic for Melitaeini. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 86 , 227–251.     

Phylogenetic relationships of Mexican minnows of the genus Notropis (Actinopterygii, Cyprinidae)

We conducted phylogenetic analyses based on complete mitochondrial cytochrome b gene sequences among southern and central Mexican cyprinid species, included in the genera Notropis and Hybopsis. In addition 15 northern species of the genera Notropis and Hybopsis were included in the analyses in order to place the Mexican species into a larger phylogenetic framework. The phylogenetic relationships supported the existence of five major clades: (1) including species of the subgenus Alburnops of the genus Notropis plus N. shumardi; (2) species of the subgenus Notropis; (3) species of the genus Hybopsis; (4) species of the N. texanus + N. volucellus species group of the genus Notropis; (5) Mexican endemic species of the genus Notropis plus the genus Yuriria. Previous phylogenetic inferences based on morphological characters resolved the Mexican minnows analysed as N. sallaei, N. calientis, N. boucardi and Y. alta, non‐monophyletic. According to our cytochrome b evidence all Mexican minnows of the genera Notropis and Yuriria formed a monophyletic group with respect to the northern species of the genera Notropis and Hybopsis. Within the Mexican clade, three well‐supported clades were identified: the first included the closely related species N. moralesi and N. boucardi, which occur in three independent drainages of south Mexico; the second consisted of two different lineages, N. imeldae and an undescribed species of Notropis, inhabiting two independent drainages of south Mexico; the third comprised two central Mexican Notropis species (N. calientis and N. sallaei) and the Y. alta populations. Based on this study and pending a more extensive taxonomic revision of the genus Notropis, we adopt the conservative criterion of considering all Notropis species from southern and central Mexico examined, including Y. alta, as belonging to the genus Notropis. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society, 2003, 80 , 323–337.     

Morphological and molecular description of new species of squat lobster (Crustacea: Decapoda: Galatheidae) from the Solomon and Fiji Islands (South‐West Pacific)

The family Galatheidae is among the most diverse families of anomuran decapod crustaceans, and the South‐West Pacific is a biodiversity hot spot for these squat lobsters. Attempts to clarify the taxonomic and evolutionary relationships of the Galatheidae on the basis of morphological and molecular data have revealed the existence of several cryptic species, differentiated only by subtle morphological characters. Despite these efforts, however, relationships among genera are poorly understood, and the family is in need of a detailed systematic review. In this study, we assess material collected in different surveys conducted in the Solomon Islands, as well as comparative material from the Fiji Islands, by examining both the morphology of the specimens and two mitochondrial markers (cytochrome oxidase subunit I, COI, and 16S rRNA). These two sources of data revealed the existence of eight new species of squat lobster, four of which were ascribed to the genus Munida, two to the genus Paramunida, one to the genus Plesionida, and the last species was ascribed to the genus Agononida. These eight species are described along with phylogenetic relationships at the genus level. Our findings support the taxonomic status of the new species, yet the phylogenetic relationships are not yet fully resolved. Further molecular analysis of a larger data set of species, and more conserved genes, will help clarify the systematics of this group. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 156 , 465–493.     

Barcoding,molecular taxonomy,and exploration of the diversity of shrews (Soricomorpha: Soricidae) on Mount Nimba (Guinea)

We tested the efficiency of cytochrome oxidase I (COI)‐barcoding as a taxonomic tool to discriminate and identify sympatric shrew species on Mount Nimba (Guinea). We identified 148 specimens at the species level using morphological characters and comparison with type specimens, including several taxa from Mount Nimba. We identified ten morphospecies and tested aspects of genetic diversity and monophyly using genetic data from three mitochondrial (16S, cytochrome b, and COI) and one nuclear marker (the breast cancer gene, BRCA). Nine morphospecies were validated under the phylogenetic and genetic species concepts, including the recently diverged species Crocidura buettikoferi, Crocidura theresae, and Crocidura grandiceps. Under the same concepts, our analyses revealed the presence of two cryptic species amongst animals identified as Crocidura muricauda. We then tested the efficiency of barcoding thanks to commonly used phenetic methods, with the 148 specimens representing 11 potentially valid species based on morphological and molecular data. We show that COI‐barcoding is a powerful tool for shrew identification and can be used for taxonomic surveys. The comparison of genetic divergence values shows the presence of a barcoding gap (i.e. difference between the highest intraspecific and the lowest interspecific genetic divergence values). Given that only a few COI sequences are available for Afrotropical shrews, our work is an important step forward toward their enrichment. We also tested the efficiency of the three other sequenced markers and found that cytochrome b is as efficient as COI for barcoding shrews. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166 , 672–687.     

Genetic variation in the stygobitic shrimp Creaseria morleyi (Decapoda: Palaemonidae), evidence of bottlenecks and re‐invasions in the Yucatan Peninsula

The karstic nature of the Yucatan Peninsula promotes the formation of submerged caves and sinkholes that are inhabited by an endemic subterranean water fauna. By contrast with most other micro‐endemic stygobitic species, the freshwater palaemonid shrimp Creaseria morleyi is widely distributed across the northern part of the peninsula. In the present study, we investigated the phylogeographic structure of C. morleyi using two mitochondrial genes as markers, and explored hypotheses related to its evolution in the peninsula. DNA from 14 localities was extracted, and the 16S rRNA and cytochrome oxidase subunit I (COI) genes were amplified and sequenced. The different haplotypes were identified to construct a haplotype network and perform a nested clade analysis. Five haplotypes of the 16S gene were obtained, with a maximum divergence of 0.5%. One of these haplotypes is widely distributed and the most divergent is located in the north‐western section of the peninsula. Twelve haplotypes for the COI gene were found with a maximum divergence of 2%, showing the same spatial pattern. The analysis revealed two significantly different clades corresponding to populations in the centre and south‐east of the peninsula as a consequence of restricted genetic flow with isolation‐by‐distance. The divergence time of these two clades was 40–120 thousand years. The genetic variation in C. morleyi, the relationship between haplotypes and their geographic distribution, along with the geological history of the Yucatan Peninsula, may indicate that this variation is a relict of an ancient marked genetic structure reduced by changes in sea level that resulted in a series of bottlenecks. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 315–325.     

Genets (Carnivora, Viverridae) in Africa: an evolutionary synthesis based on cytochrome b sequences and morphological characters

The taxonomy of the genets (genus Genetta) has long been discussed, thus hampering endeavours towards evolutionary reconstruction. Sequence data from the complete cytochrome b gene (cyt b) were generated for 50 specimens representing 15 morphological species in order to allow the production of the first exhaustive molecular phylogeny of the genets. Second, a revised morphological matrix comprising 50 characters was combined with the cyt b data to estimate the level of morphological homoplasy. Phylogenetic analyses were conducted using parsimony, maximum likelihood and Bayesian procedures. Our results based on cyt b contradict a part of the traditional taxonomy of genus Genetta, the servaline and small‐spotted genets being paraphyletic, but confirmed the species status recently re‐investigated for three genets belonging to the large‐spotted complex, including the newly described G. bourloni. The combined analysis yielded similar results although morphological characters were clearly homoplasic. Partitioned Bremer supports indicated conflicting signals between the two data sets throughout the tree, and species‐diagnostic characters, useful for delimiting species boundaries, were significantly correlated to habitat. However, morphological data supported the monophyly of clades (G. victoriae, other genets) (G. servalina, G. cristata), large‐spotted genet complex and forest forms. Our results suggest a complex evolutionary history of the genets in Africa, with a Poiana‐like ancestor inhabiting rain forest, and then a diversification involving two independent invasions of open habitats and one reversion to rain forest. Divergence estimates based on cyt b revealed that splitting events within genets partly follow a climatic speciation model during the cyclical periods of the Quaternary, although ‘primitive’ rain forest lineages diverged earlier, during the Late Miocene and Early Pliocene. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 81 , 589–610.     

Cryptic speciation at organic‐rich marine habitats: a new bacteriovore annelid from whale‐fall and fish farms in the North‐East Atlantic

Vigtorniella ardabilia sp. nov. , a new chrysopetalid annelid, is described from a whale‐fall in Sweden and from sediment samples collected beneath fish farms in Norway. The new Vigtorniella species is morphologically almost identical to Vigtorniella flokati from whale‐falls in the Pacific Ocean, although molecular evidence from four genes shows that they are different species. Population genetic structure and phylogenetic relationships of V. ardabilia sp. nov. were assessed using molecular data from the nuclear genes 18S and 28S, and the mitochondrial 16S and cytochrome c oxidase subunit I (COI). High levels of gene flow are reported between contrasting organic‐rich environments in the North Atlantic (fish farms and whale‐fall). Observations of feeding biology and habitat suggest that V. ardabilia specializes on bacterial mats, rather than on whale‐falls, although the two species of Vigtorniella for which data were available show very different feeding behaviours. Our results further showed an unexpectedly low divergence rate in Vigtorniella for the mitochondrial markers, suggesting stabilizing selection. Analyses carried out with parsimony, maximum likelihood, and MrBayes all placed the genus Vigtorniella as sister group to Dysponetus, suggesting a close evolutionary link to sediment‐dwelling fauna. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 774–785.     

Are there two cryptic species of the lesser jerboa Jaculus jaculus (Rodentia: Dipodidae) in Tunisia? Evidence from molecular,morphometric, and cytogenetic data

Jerboas belonging to the genus Jaculus are widely distributed rodents inhabiting Palearctic desert and semi‐desert areas. Previous studies on the lesser Egyptian jerboa Jaculus jaculus showed the existence of various morphological forms of controversial taxonomic status. They were sometimes related to two different species, J. jaculus and Jaculus deserti, although this has not been recognized in recent taxonomic updates. To clarify the systematic status of J. jaculus in Tunisia, we performed molecular (phylogenetic analyses of cytochrome b sequences), morphological (multivariate analyses of 13 skull measurements) and karyotypic (standard preparations from bone marrow cells) analyses on a number of specimens collected from ten localities. Our analyses revealed two monophyletic, well differentiated clades, with a mean genetic divergence value (K2P = 10.9 ± 0.01%), which is within the range of distances generally observed between rodent species. Morphometric analyses clearly separated populations of the two genetic clades from each other. However, karyotypes of individuals from both clades appeared similar. Individuals from both molecular clades/morphometric groups were found in sympatry in most of the localities sampled. These results, as obtained from a restricted area of the total distribution, suggest that there are two separate species within the currently accepted J. jaculus in Tunisia. Alternative hypotheses such as the occurrence of a strong, ancient phylogeographic structure, or the presence of pseudogenes, are also considered to account for the results obtained. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 673–686.     

Molecular phylogeny of the Eremias persica complex of the Iranian plateau (Reptilia: Lacertidae), based on mtDNA sequences

The Persian racerunner Eremias persica Blanford, 1875 is confined to the Iranian plateau, and forms one of the most widespread but rarely studied species of the family Lacertidae. With many local populations inhabiting a variety of habitats, and exhibiting considerable morphological, genetic, and ecological variations, it represents a species complex. We analysed sequences of mitochondrial cytochrome b and 12S ribosomal RNA (rRNA) genes derived from 13 geographically distant populations belonging to the E. persica complex. Using our knowledge of palaeogeographical events, a molecular clock was calibrated to assess the major events in fragmentation, radiation, and intraspecific variation. The sequence data strongly support a basal separation of the highland populations of western Iran from those of the open steppes and deserts, occurring in the east. The subsequent radiation, fragmentation, and evolution of these major assemblages have led to several discernable geographical lineages across the wide area of the Iranian plateau. The results indicate a middle‐Miocene origin for the clade as a whole. The first split, isolating the western and eastern clades, appears to have occurred 11–10 Mya. Further fragmentations and divergence within the major clades began about 8 Mya, with an evolutionary rate of 1.6% sequence divergence per million years among the lineages in the genes studied (combined data set). Molecular and morphological data strongly support a taxonomic revision of this species complex. At least four of the discovered clades should be raised to species, and two to subspecies, rank. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 641–660.     

Phylogenetics of Escallonia (Escalloniaceae) based on plastid DNA sequence data

Escallonia (Escalloniaceae) is a New World genus of c. 39 species distributed mainly in the South American highlands. Plastid DNA sequence data from the intergenic spacers trnS‐trnG and 3′ trnV‐ndhC and the ndhF gene for 32 species were used to examine the relationships among species and related genera and to analyse the relationship between phylogeny and the geographical distribution of the species. Maximum parsimony and Bayesian inference were employed to analyse the data. The sister relationship of Escallonia to Forgesia and Valdivia was corroborated. We recovered five strongly supported clades that are geographically structured, suggesting that the evolutionary history of the genus may be linked to historical processes, including the uplift of mountainous systems in South America. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 442–451.     

Molecular phylogeny and phylogeography of the Greek populations of the genus Orthometopon (Isopoda, Oniscidea) based on mitochondrial DNA sequences

We infer phylogenetic relationships among isopod species of the genus Orthometopon distributed in the Greek area, comparing partial mitochondrial DNA sequences for cytochrome oxidase I (COI). All phylogenetic analyses produced topologically identical trees that revealed a well-resolved phylogeny. These trees support the monophyly of the genus Orthometopon , and suggest two clades that correspond to separate geographical regions (west and east of the mid-Aegean trench). However, the phylogenetic relationships among Greek populations of Orthometopon spp. are different from the presumed pattern on the basis of morphological evidence. The distinct geographical distribution of the major clades of the phylogenetic tree and its topology suggest a spatial and temporal sequence of phylogenetic separations, which coincide with some major palaeogeographical separations during the geological history of the Aegean Sea. The results stress the need for a reconsideration of the evolutionary history of Orthometopon species, which will help overcome difficulties encountered in classical taxonomy at the species level. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 152 , 707–715.     

Phylogenetics and morphological evolution of coral‐dwelling barnacles (Balanomorpha: Pyrgomatidae)

Pyrgomatid barnacles are a family of balanomorphs uniquely adapted to symbiosis on corals. The evolution of the coral‐dwelling barnacles is explored using a multi‐gene phylogeny (COI, 16S, 12S, 18S, and H3) and phenotypic trait‐mapping. We found that the hydrocoral associate Wanella should be excluded, while some archaeobalanids in the genus Armatobalanus should be included in the Pyrgomatidae. Three well supported clades were recovered: clade I is the largest group and is exclusively Indo‐West Pacific, clade II contains two plesiomorphic Indo‐West Pacific genera, while clade III is comprised of East and West Atlantic taxa. Some genera did not form reciprocally monophyletic groups, while the genus Trevathana was found to be paraphyletic and to include members of three other apomorphic genera/tribes. The highly unusual coral‐parasitic hoekiines appear to be of recent origin and rapidly evolving from Trevathana sensu lato. Pyrgomatids include six‐, four‐, and one‐plated forms, and exhibit convergent evolutionary tendencies towards skeletal reduction and fusion, loss of cirral armature, and increased host specificity. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 162–179.     

The molecular phylogeny of the sea star Echinaster (Asteroidea: Echinasteridae) provides insights for genus taxonomy

In this study, we used sequences of two mitochondrial genes, cytochrome c oxidase I (COI) and 16S rRNA, and one nuclear gene, 28S rRNA, to test the monophyly of the sea star genus Echinaster, and understand the phylogenetic relationships among species and subgenera within this genus. Phylogenetic analyses based on Bayesian inference and maximum likelihood methods revealed three clades with high values of genetic divergence among them (K2P distances for COI over 23%). One of the clades grouped all Echinaster (Othilia) species, and the other two clades included Echinaster (non‐Othilia) species and Henricia species, respectively. Although the relationships among Henricia, Othilia, and Echinaster could not be completely clarified, the Othilia clade was a well‐supported group with shared diagnostic morphological characters. Moreover, the approximately unbiased test applied to the phylogenetic reconstruction rejected the hypothesis of the genus Echinaster as a monophyletic group. According to these results, we suggest the revalidation of Othilia as a genus instead of a subgenus within Echinaster. Our study clarifies important points about the phylogenetic relationships among species of Echinaster. Other important systematic questions about the taxonomic classification of Echinaster and Henricia still remain open, but this molecular study provides bases for future research on the topic.