Phylogeny and Evolutionary History of the Ground Squirrels (Rodentia: Marmotinae)

Although ground squirrels (Spermophilus) and prairie dogs (Cynomys) are among the most intensively studied groups of mammals with respect to their ecology and behavior, a well-resolved phylogeny has not been available to provide a framework for comparative and historical analyses. We used complete mitochondrial cytochrome b sequences to construct a phylogeny that includes all 43 currently recognized species in the two genera, as well as representatives of two closely related genera (Marmota and Ammospermophilus). In addition, divergence times for ground squirrel lineages were estimated using Bayesian techniques that do not assume a molecular clock. All methods of phylogenetic analysis recovered the same major clades, and showed the genus Spermophilus to be paraphyletic with respect to both Marmota and Cynomys. Not only is the phylogeny at odds with previous hypotheses of ground squirrel relationships, but it suggests that convergence in morphology has been a common theme in ground squirrel evolution. A well-supported basal clade, including Ammospermophilus and two species in the subgenus Otospermophilus, diverged from all other ground squirrels an estimated 17.5 million years ago. Between 10 and 14 million years ago, a relatively rapid diversification gave rise to lineages leading to marmots and to several distinct groups of ground squirrels. The Eurasian ground squirrels diverged from their North American relatives during this period, far earlier than previously hypothesized. This period of diversification corresponded to warming climate and spread of grasslands in western North America and Eurasia. Close geographic proximity of related forms suggests that most species evolved in or near their current ranges.     

Phylogeny of salmonids (salmoniformes: Salmonidae) and its molecular dating: Analysis of mtDNA data

Phylogenetic relationships among 41 species of salmonid fish and some aspects of their diversification-time history were studied using the GenBank and original mtDNA data. The position of the root of the Salmonidae phylogenetic tree was uncertain. Among the possible variants, the most reasonable seems to be that in which thymallins are grouped into the same clade as coregonins and the lineage of salmonins occupied a basal position relative to this clade. The genera of Salmoninae formed two distinct clades, i.e., (Brachymystax, Hucho) and (Salmo, Parahucho, (Salvelinus, (Parasalmo, Oncorhynchus)). Furthermore, the genera Parasalmo and Oncorhynchus were reciprocally monophyletic. The congruence of Salmonidae phylogenetic trees obtained using different types of phylogenetic markers is discussed. According to Bayesian dating, ancestral lineages of salmonids and their sister esocoids diverged about 106 million years ago. Sometime after, probably 100–70 million years ago, the salmonid-specific whole genome duplication took place. The divergence of salmonid lineages on the genus level occurred much later, within the time interval of 42–20 million years ago. The main wave of the diversification of salmonids at the species level occurred during the last 12 million years. The possible effect of genome duplication on the Salmonidae diversification pattern is discussed.     

Phylogenetic relationships within the South American fish family Anostomidae (Teleostei,Ostariophysi, Characiformes)

Analysis of a morphological dataset containing 152 parsimony‐informative characters yielded the first phylogenetic reconstruction spanning the South American characiform family Anostomidae. The reconstruction included 46 ingroup species representing all anostomid genera and subgenera. Outgroup comparisons included members of the sister group to the Anostomidae (the Chilodontidae) as well as members of the families Curimatidae, Characidae, Citharinidae, Distichodontidae, Hemiodontidae, Parodontidae and Prochilodontidae. The results supported a clade containing Anostomus, Gnathodolus, Pseudanos, Sartor and Synaptolaemus (the subfamily Anostominae sensu Winterbottom) albeit with a somewhat different set of relationships among the species within these genera. Anostomus as previously recognized was found to be paraphyletic and is split herein into two monophyletic components, a restricted Anostomus and the new genus Petulanos gen. nov. , described herein. Laemolyta appeared as sister to the clade containing Anostomus, Gnathodolus, Petulanos, Pseudanos, Sartor and Synaptolaemus. Rhytiodus and Schizodon together formed a well‐supported clade that was, in turn, sister to the clade containing Anostomus, Gnathodolus, Laemolyta, Petulanos, Pseudanos, Sartor and Synaptolaemus. Anostomoides was sister to the clade formed by these nine genera. Leporinus as currently defined was not found to be monophyletic, although certain clades within that genus were supported, including the species with subterminal mouths in the former subgenus Hypomasticus which we recognize herein as a genus. Abramites nested in Leporinus, and Leporellus was found to be the most basal anostomid genus. The presence of cis‐ and trans‐Andean species in Abramites, Leporellus, Leporinus and Schizodon, all relatively basal genera, suggests that much of the diversification of anostomid species pre‐dates the uplift of the Andean Cordilleras circa 11.8 million years ago. Several important morphological shifts in anostomid evolution are illustrated and discussed, including instances of convergence and reversal. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154 , 70–210.     

Biochemical and molecular characterisation of hemocyanin from the amphipod <Emphasis Type="Italic">Gammarus roeseli</Emphasis>: complex pattern of hemocyanin subunit evolution in Crustacea

Hemocyanin is a copper-containing respiratory protein that is widespread within the arthropod phylum. Among the Crustacea, hemocyanins are apparently restricted to the Malacostraca. While well-studied in Decapoda, no hemocyanin sequence has been known from the ’lower’ Malacostraca. The hemocyanin of the amphipod Gammarus roeseli is a hexamer that consists of at least five distinct subunits. The complete cDNA sequence of one subunit and a tentative partial sequence of another subunit have been determined. The complete G. roeseli hemocyanin subunit comprises 2,150 bp, which translates in a protein of 672 amino acids with a molecular mass of 76.3 kDa. Phylogenetic analyses show that, in contrast to previous assumptions, the amphipod hemocyanins do not belong to the α-type of crustacean hemocyanin subunits. Rather, amphipod hemocyanins split from the clade leading to α and γ-subunits most likely at the time of separation of peracarid and eucarid Crustacea about 300 million years ago. Molecular clock analyses further suggest that the divergence of β-type subunits and other crustacean hemocyanins occurred around 315 million years ago (MYA) in the malacostracan stemline, while α- and γ-type subunits separated 258 MYA, and pseudohemocyanins and γ-subunits 210 million years ago.     

Differentiation of Fraction 1 protein in relation to age and distribution of Angiosperm groups

Fraction 1 protein (F-1-protein) (ribulose bisphosphate carboxy-lase-oxygenase) contained inLemnaceae has been evolving for at least 50 million years because fossils of these plants have been identified in strata belonging to the Upper Cretaceous. Electrofocusing F-1-protein resolves the large subunit polypeptides coded by extranuclear DNA and the small subunit polypeptides coded by nuclear DNA. Four differences affecting isoelectric points of the large subunit polypeptides and eight affecting the small subunit polypeptides are now present among eleven species representing the four genera comprising theLemnaceae. In comparison, four differences in the large and 13 in the small subunit polypeptides exist among 63 species ofNicotiana; four differences in the large and eight differences in the small subunit polypeptides exist among 19 species ofGossypium. The number of differences in F-1-protein composition being of the same order of magnitude for the generaNicotiana, Gossypium, and the familyLemnaceae, we infer that these Angiosperms are of similar antiquity. Nicotiana species indigenous to Australia and Africa contain F-1-proteins whose large subunit polypeptides are different but some of whose small subunit polypeptides are like those found in species from the Western Hemisphere. The same situation is found for the F-1-protein inGossypium. These results are in harmony with the view that species ofNicotiana andGossypium have arrived in Australia via former land connections between S. America, Antarctica, and Australia.     

Molecular systematics and phylogeography of the gigantic earthworms of the Metaphire formosae species group (Clitellata, Megascolecidae)

The earthworms of the Metaphire formosae species group distributed in Taiwan are members of the Pheretima complex within the Megascolecidae. In this study, the systematics and phylogeography of this species group were investigated using DNA sequences of mitochondrial cytochrome c oxidase subunit I (COI), 16S ribosomal (r)RNA, and NADH dehydrogenase subunit 1 (ND1). The results indicated that the 13 taxa of the M. formosae species group form a clade, including a cryptic species discovered in this study. In addition, Metaphire hengchunensis (James, S.W., Shih, H.-T., Chang, H.-W., 2005. Seven new species of Amynthas (Clitellata: Megascolecidae) and new earthworm records from Taiwan. J. Nat. Hist. 39, 1007-1028) should be regarded as a subspecies of Metaphire paiwanna Tsai, C.-F., Shen, H.-P., Tsai, S.-C., 2000a. Native and exotic species of terrestrial earthworm (Oligochaeta) in Taiwan with reference to Northeast Asia. Zool. Stud. 39, 285-294, Tsai, C.-F., Tsai, S.-C., Liaw, G.-J., 2000b. Two new species of pontandric pheretimoid earthworms belonging to the genus Metaphire (Megascolecidae: Oligochaeta) from Taiwan. J. Nat. Hist. 34, 1731-1741, and Metaphire bununa glareosa Tsai et al. 2000 should be elevated to specific status. Phylogeographical inferences showed that allopatric speciation occurred in this species group during the rapid uplift of the main island of Taiwan between 5.0 and 2.5 million years ago. Our analysis exposes non-monophyly within each of the genera Amynthas and Metaphire, and more generally within the Pheretima complex. Further revisions of this speciose complex are urgently needed.     

Differences in amino acid sequence of the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase from two species of Dasycladaceae

In contrast to other plants the plastid genome of Acetabularia is larger in size and shows a high degree of variability. This study on the chloroplast-encoded large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase demonstrates that strongly conserved areas also exist in the plastid genome of the Dasycladaceae. Searching for differences in the amino acid sequence of the large subunit from Acetabularia mediterranea and Acicularia schenckii, proteolytic peptides which differ in their elution behaviour in reverse-phase high-performance liquid chromatography were sequenced. Only six amino acids were found to be exchanged in the large subunit from these two species. Since these two species diverged approx. 150 million years ago, these results imply that 0.84 amino-acid exchanges per 100 amino acids have occurred in 10⁸ years, underlining the strong conservatism of the large subunit.Abbreviations A Acetabularia mediterranea - Ac. Acicularia schenckii - HPLC high-performance liquid chromatography - LSU large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase - PAGE polyacrylamide gel electrophoresis - RuBPCase ribulose-1,5-bisphosphate carboxylase/oxygenase - SDS sodium dodecyl sulfate     

Monophyly and relationships of the tribe Exaceae (Gentianaceae) inferred from nuclear ribosomal and chloroplast DNA sequences

Both chloroplast trnL (UAA) intron and nuclear ribosomal ITS sequences highly confirmed the monophyly of the tribes of the Gentianaceae defined by the recent classification, and revealed the tribe Exaceae as a basal clade just next to the basal-most lineage, the tribe Saccifolieae. Within the tribe Exaceae, Sebaea (except Sebaea madagascariensis) appeared as the most basal clade as the sister group to the rest of the tribe. The Madagascan endemic genera Gentianothamnus and Tachiadenus were very closely related to each other, together standing as sister to a clade comprising Sebaea madagascariensis, Ornichia, and Exacum. The saprophytic genus Cotylanthera nested deeply inside Exacum. Sebaea madagascariensis was shown closer to the Madagascan endemic genus Ornichia than to any other sampled Sebaea species. Exacum appeared as the most derived taxon within this tribe. The topology of the phylogenetic trees conform with the Gondwana vicariance hypothesis regarding the biogeography of Exaceae. However, no evidence for matching the older relationships within the family to the tectonic history could be corroborated with various divergence time analyses. Divergence dating estimated a post-Gondwana diverging of the Gentianaceae about 50 million years ago (MYA), and the tribe Exaceae as about 40 MYA. The Mozambique Channel land-bridge could have played an important role in the biogeographic history of the tribe Exaceae.     

Phylogeny of Chinese <Emphasis Type="Italic">Polystichum</Emphasis> (Dryopteridaceae) based on chloroplast DNA sequence data (<Emphasis Type="Italic">trnL-F</Emphasis> and <Emphasis Type="Italic">rps4-trnS</Emphasis>)

Polystichum is one of the largest and most taxonomically complex fern genera in China. The evolutionary relationships of Chinese Polystichum and related genera, and the relationship between our Polystichum phylogeny and ecogeographic distribution, were tested by the use of DNA sequence data. Fifty-one species of Polystichum and 21 species in allied genera were sequenced for the plastid intergenic spacers rps4-trnS and trnL-F. Maximum parsimony and Bayesian phylogenetic analyses of both individual and combined data sets showed that Chinese Polystichum as commonly recognized was paraphyletic: one clade (the CCPC clade) included Cyrtomidictyum lepidocaulon, two Cyrtogonellum species, three Cyrtomium species, and a small number of Polystichum species usually occurring on limestone. A second clade, Polystichum sensu stricto, included the remainder of the Polystichum species; these often occur on non-limestone substrates. The remaining Cyrtomium species formed the third clade. Three subclades resolved within Polystichum sensu stricto (s.s.) clade do not correspond with recent sectional classifications, and we outline the issues relevant to a new classification for the genus. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Genetic diversity and phylogenetic position of the subclass Astomatia (Ciliophora) based on a sampling of six genera from West African oligochaetes (Glossoscolecidae, Megascolecidae), including description of the new genus Paraclausilocola n. gen

To more confidently assess phylogenetic relationships among astome ciliates, we obtained small subunit (SSU) rRNA sequences from nine species distributed in six genera and three families: Almophrya bivacuolata, Eudrilophrya complanata, Metaracoelophrya sp. 1, Metaracoelophrya sp. 2, Metaracoelophrya intermedia, Metaradiophrya sp., Njinella prolifera, Paraclausilocola constricta n. gen., n. sp., and Paraclausilocola elongata n. sp. The two new species in the proposed new clausilocolid genus Paraclausilocola n. gen. are astomes with no attachment apparatus, two files of contractile vacuoles, and an arc-like anterior suture that has differentiations of thigmotactic ciliature on the anterior ends of the left kineties of the upper surface. Phylogenetic analyses were undertaken using neighbor-joining, Bayesian inference, maximum likelihood, and maximum parsimony. The nine species of astomes formed a strongly supported clade, showing the subclass Astomatia to be monophyletic and a weakly supported sister clade to the scuticociliates. There were two strongly supported clades within the astomes. However, genera assigned to the same family were found in different clades, and genera assigned to the same order were found in both clades. Thus, astome taxa appear to be paraphyletic when morphology is used to assign species to genera.     

Update on the Phylogenetic Systematics of New World Monkeys: Further DNA Evidence for Placing the Pygmy Marmoset (Cebuella) within the Genus Callithrix

We determined DNA sequences spanning the 1.8-kb long intron 1 of the interstitial retinol-binding protein nuclear gene (IRBP) for Callithrix geoffroyi, Callithrix humeralifer, and Callithrix argentata. With the 22 previously determined IRBP intron 1 sequences—21 from the 16 currently recognized genera of New World monkeys—the enlarged IRBP data represent for the marmoset genus Callithrix both its argentata and its jacchus species groups. Maximum-parsimony and neighbor-joining trees, constructed for the 25 aligned IRBP intron 1 sequences, support a provisional phylogenetic classification with three families: Atelidae, containing subfamily Atelinae; Pitheciidae, containing subfamily Pitheciinae; and Cebidae, containing subfamilies Cebinae, Aotinae, and Callitrichinae. In order to have taxa at the same hierarchical rank at equivalent age, this classification has all living callitrichines in a single tribe, Callitrichini, with four subtribes: Saguinina (Saguinus), Callimiconina (Callimico), Leontopithecina (Leontopithecus), and Callitrichina (Callithrix with the pygmy marmoset, Cebuella pygmaea, merged into it). The DNA evidence shows not only that Callithrix must include C. pygmaea to be monophyletic but also that the times of separation of pygmaea and the argentata and jacchus species groups from one another are to be expected (<5 Ma—million years ago) for species in a single genus. On relating the time course of the ceboid radiation to biogeographic information, it appears that in mid-Miocene times (10–11 Ma) a basal callitrichin stock branched into the ancestral population of Saguinus in one clade and the ancestral population of Leontopithecus and Callimico–Callithrix (or Leontopithecus–Callimico and Callithrix) in another clade. The proto-lion tamarins migrated south and eastward, where they were isolated in refugia, becoming the genus Leontopithecus. The stock remaining in Amazonia gave rise to present-day Callimico and Callithrix. The latter genus occupied a vast geographic area, giving rise to the argentata and pygmaea groups in Amazonia and to the jacchus group in central and eastern Brazil.     

Phylogeography and population structure of the endangered Tehuantepec jackrabbit <Emphasis Type="Italic">Lepus flavigularis</Emphasis>: implications for conservation

The Tehuantepec jackrabbit (Lepus flavigularis) is an endangered species restricted to a small area in the Isthmus of Tehuantepec, Oaxaca, Mexico. To evaluate its phylogeographic structure, population genetics, and demographic history we sequenced the mitochondrial Control Region hypervariable domain (CR-1) for 42 individuals representing the entire species range. Phylogenetic patterns indicated that this species is subdivided into two highly divergent clades, with an average nucleotide genetic distance of 3.7% (TrN) between them. Clades A and B are geographically distributed in non-overlapping areas to the west and to the east of the Isthmus of Tehuantepec, respectively. Genetic diversity indices showed reduced genetic variability in L. flavigularis when compared to other species of Lepus within main clades and within populations. This low genetic diversity coupled with the restricted distribution to very small areas of occurrence and limited gene flow suggest that genetic drift has played an important role in the evolution of this species. Historical demographic analysis also pointed out that these two clades underwent a recent population expansion that started about 9,000 years ago for clade A and 3,200 years ago for clade B during the Holocene. Consequently, from the conservation perspective our results suggest that populations included in clades A and B should be regarded as distinct evolutionary lineages.     

Mitochondrial phylogeography of a leafminer parasitoid, Diglyphus isaea (Hymenoptera: Eulophidae) in China

Diglyphus isaea is one of the primary parasitoids of agromyzid leafminers. Mitochondrial cytochrome oxidase subunit I sequences from 10 Chinese localities were used to investigate geographic variation within this widespread and morphologically uniform parasitoid. Phylogeographic analyses and sequence variation indicated that this species was actually a species-complex. We used an amber fossil record of the genus Entedon (Eulophidae: Entedoninae) as a reference to estimate the divergence time of major clades within D. isaea. With reference to the fossil record of its hosts, our results indicate that associations between parasitoids and leaf-miners could have been possibly established 38.2 million years ago.     

Grazing insects reduce algal biomass in a neotropical stream

The Darwinulidae are the only surviving post-Palaeozoic darwinulocopine family of an extensive radiation that reached its maximum in the Permian. Whereas at least some Palaeozoic darwinulids are known from sexual populations, the surviving lineages after the end-Permian mass extinction have abandoned sex since 200 million years ago. This makes the extant family Darwinulidae one of the few putative ancient asexual groups. Only about 30 species in 5 genera are presently known. The phylogeny of these taxa is here analysed using both morphological characters and molecular data. Twelve characters on valve morphology and 17 characters pertaining to appendages are used to construct the most parsimonious (unrooted) cladogram of 12 species in 5 genera. DNA sequences of one nuclear (ITS1) and a mitochondrial (COI) gene of 6 species in 5 genera are used to construct rooted maximum parsimony trees. Both molecular and morphological trees show a high degree of congruence, indicating that Alicenula and Vestalenula mostly cluster closely together, while Penthesilenula and Microdarwinula constitute a robust group. The position of the monospecific genus Darwinulais more variable, but is mostly closer to the two former genera. Congeneric species always cluster together in the morphological cladograms, and these results thus confirm that the five genera recognised by Rossetti & Martens (1998) are good phyletic units. An approximate molecular clock (calibrated with fossil data) indicates that the extant darwinulids share a common ancestor, which lived at least 100 million years ago.     

Morphology agrees with molecular data: phylogenetic affinities of Euptychiina butterflies (Nymphalidae: Satyrinae)

Euptychiina is the most species‐rich subtribe of Neotropical Satyrinae, with over 450 known species in 47 genera (14 monotypic). Here, we use morphological characters to examine the phylogenetic relationships within Euptychiina. Taxonomic sampling included 105 species representing the majority of the genera, as well as five outgroups. A total of 103 characters were obtained: 45 from wing pattern, 48 from genitalia and 10 from wing venation. The data matrix was analysed using maximum parsimony under both equal and extended implied weights. Euptychiina was recovered as monophyletic with ten monophyletic genera, contrasting previous DNA sequence‐based phylogenies that did not recover the monophyly of the group. In agreement with sequence‐based hypotheses, however, three main clades were recognized: the ‘Megisto clade’ with six monophyletic and three polyphyletic genera, the ‘Taygetis clade’ with nine genera of which three were monophyletic, and the ‘Pareuptyhia clade’ with four monophyletic and two polyphyletic genera. This is the first morphology‐based phylogenetic hypothesis for Euptychiina and the results will be used to complement molecular data in a combined analysis and to provide critical synapomorphies for clades and genera in this taxonomically confused group.     

18S rDNA AND EVOLUTION IN THE DASYCLADALES (CHLOROPHYTA): MODERN LIVING FOSSILS1

Phylogenetic relationships were inferred from parsimony and distance analyses of nuclear small-subunit ribosomal DNA sequences taken from 14 species representing 8 of the 11 extant genera in the Dasycladales. Of 1733 aligned positions, 412 (23.8%) were variable and 251 (61%) of those were phylogenetically informative within the Dasycladales. Secondary structure was analyzed and taken into account during all phases of data analysis. Robustness of the trees was assessed using bootstrap analysis and g₁ statistics of tree-length decay. Strongly supported branches were robust to all methods of analysis regardless of weighting schemes used. The secondary structure of the 18S within the Dasycladales agrees with that of other green algae with the exception of a shared deletion in stemloop E10-1 (ca. 13 nucleotides long), which provides additional support for the uniqueness of this monophyletic group. A molecular clock was calibrated from the dasyclad fossil record and suggests a radiation of the Acetabulariaceae at 120 ± 30 million years (Ma) ago and the Dasycladaceae 215 ± 40 Ma ago. The split of the two lineages from a shared ancestor is estimated at 265 ± 50 Ma ago. Within the Dasycladaceae, Neomeris and Cymopolia are sister taxa, as are Batophora and Chlorocladus. Bornetella groups with the Neomeris and Cymopolia clade in 78% of the bootstrap replicates. Relationships among the Acetabulariaceae show that Acetabularia and Polyphysa do not form monophyletic groups as presently circumscribed. No evidence indicates that Acicularia is the oldest genus. Halicoryne, Chalmasia, and Dasycladus were not included in the analysis. Molecular data provide afresh background perspective from which to discuss the evolution of one of the most ancient lineages of green plants.     

Molecular-based estimate of species number,phylogenetic relationships and divergence times for the genus Stenotaenia (Chilopoda,Geophilomorpha) in the Italian region

Stenotaenia is one of the largest and most widespread genera of geophilid centipedes in the Western Palearctic, with a very uniform morphology and about fifteen species provisionally recognized. For a better understanding of Stenotaenia species-level taxonomy, we have explored the possibility of using molecular data. As a preliminary assay, we sampled twelve populations, mainly from the Italian region, and analyzed partial sequences of the two genes COI and 28S. We employed a DNA-barcoding approach, complemented by a phylogenetic analysis coupled with divergence time estimation. Assuming a barcoding gap of 10–16% K2P pairwise distances, we found evidence for the presence of at least six Stenotaenia species in the Italian region, which started diverging about 50 million years ago, only partially matching with previously recognized species. We found that small-sized oligopodous species belong to a single clade that originated about 33 million years ago, and obtained some preliminary evidence of the related genus Tuoba being nested within Stenotaenia.     

Interrelationships of the Gastrotricha and their place among the Metazoa inferred from 18S rRNA genes

The phylum Gastrotricha includes about 700 species. They are small worm‐like organisms abundant among marine and freshwater meiobenthos. In spite of their ubiquity, diversity and relative abundance, phylogenetic relationships of these animals remain enigmatic due to the conflicting results of morphological and molecular cladistic analyses. Also unclear are the alliances within the phylum. In order to best estimate the position of Gastrotricha among the Metazoa and to shed some light on the ingroup phylogenetic relationships, small subunit (SSU) ribosomal DNA (rDNA) from 15 species of Chaetonotida (eight genera) and 28 species of Macrodasyida (26 genera) were included in an alignment of 50 metazoan taxa representing 26 phyla. Of the gastrotrich SSU rDNA sequences, eight are new and, along with published sequences represent eight families, including the five marine most speciose. Gastrotricha were resolved within a monophyletic Lophotrochozoa as part of a clade including Micrognathozoa, Rotifera and Cycliophora. The Gnathostomulida were sister to this clade. Nodal support was low for all of these relationships except the grouping of the Micrognathozoa, Rotifera and Cycliophora. Bayesian inference resolved the Gastrotricha as monophyletic with weak nodal support; the Macrodasyida were resolved as paraphyletic with many basal nodes poorly supported. Within the Chaetonotida, the monotypic Multitubulatina Neodasys was found in alliance with the macrodasyidan Urodasys while all the Paucitubulatina were found to form a single, well‐supported clade, with Musellifer as the most basal member. Among the more densely sampled Macrodasyida the Lepidodasyidae and Macrodasyidae were each found to be polyphyletic while monophyly was well supported for the Turbanellidae and Thaumastodermatidae. The congruence of our results with those of the cladistic analysis based on morphological traits provides confidence about the value of each dataset, and calls for widening of the research to include additional taxa of particular phylogenetic significance such as the Dactylopodolidae, Diuronotus, Heteroxenotrichula and Draculiciteria. The study highlights the problems in working with small species, the need for voucher specimens and the confused taxonomic status and membership of various gastrotrich families.     

Phylogeny and divergence times of some racerunner lizards (Lacertidae: Eremias) inferred from mitochondrial 16S rRNA gene segments

Eremias, or racerunners, is a widespread lacertid genus occurring in China, Mongolia, Korea, Central Asia, Southwest Asia and Southeast Europe. It has been through a series of taxonomic revisions, but the phylogenetic relationships among the species and subgenera remain unclear. In this study, a frequently studied region of the mitochondrial 16S rRNA was used to (i) reassess the phylogenetic relationships of some Eremias species, (ii) test if the viviparous species form a monophyletic group, and (iii) estimate divergence time among lineages using a Bayesian relaxed molecular-clock approach. The resulting phylogeny supports monophyly of Eremias sensu Szczerbak and a clade comprising Eremias, Acanthodactylus and Latastia. An earlier finding demonstrating monophyly of the subgenus Pareremias is corroborated, with Eremias argus being the sister taxon to Eremias brenchleyi. We present the first evidence that viviparous species form a monophyletic group. In addition, Eremias przewalskii is nested within Eremias multiocellata, suggesting that the latter is likely a paraphyletic species or a species complex. Eremias acutirostris and Eremias persica form a clade that is closely related to the subgenus Pareremias. However, the subgenera Aspidorhinus, Scapteira, and Rhabderemias seem not to be monophyletic, respectively. The Bayesian divergence-time estimation suggests that Eremias originated at about 9.9 million years ago (with the 95% confidence interval ranging from 7.6 to 12 Ma), and diversified from Late Miocene to Pleistocene. Specifically, the divergence time of the subgenus Pareremias was dated to about 6.3 million years ago (with the 95% confidence interval ranging from 5.3 to 8.5 Ma), which suggests that the diversification of this subgenus might be correlated with the evolution of an East Asian monsoon climate triggered by the rapid uplift of the Tibetan Plateau approximately 8 Ma.