Phylogenetic relationships of Western Mediterranean subterranean Trechini groundbeetles (Coleoptera: Carabidae)

Faille, A., Casale, A. & Ribera, I. (2010). Phylogenetic relationships of Western Mediterranean subterranean Trechini groundbeetles (Coleoptera: Carabidae). —Zoologica Scripta, 40, 282–295. Carabid beetles of tribe Trechini (Coleoptera) are one of the main groups of insects that colonized the subterranean environment. Many species of this group have developed similar morphological modifications related to the subterranean life, resulting in a characteristic Aphaenops‐like phenotype that obscures their phylogenetic relationships (depigmented, blind, elongated body and appendages, narrow head and pronotum). We present here the result of a molecular study using a combination of nuclear (small ribosomal unit, large ribosomal unit) and mitochondrial (cox1, cyb, rrnL, trnL, nad1) genes to investigate the phylogenetic placement of the highly modified subterranean genera of the tribe Trechini from the west Mediterranean area (France, Spain, Morocco and Sardinia). Our results confirm the multiple independent origin of troglomorphism among these genera, and reveal a pattern largely determined by geographical proximity. We discuss the validity of some groups proposed on the base of morphological features, and provide estimates of divergence between subterranean genera and other groups of Trechini, including epigean species of the same area. We compare the estimated age for the origin of the main groups resulting from two different calibrations, using one the standard mitochondrial mutation rate (2.3% divergence per Myr) and the other the separation between Sardinia and mainland 33 Ma. Under the first scenario, the main groups of genera would have a late Miocene origin, with a subsequent colonization of north Africa at the Pliocene–Pleistocene boundary. The assumption that the main groups originated through vicariance due to the separation of the Sardinian plate in the Oligocene results in a Messinian origin of the north African subterranean taxa, and a global mitochondrial rate reduced to 1% divergence per Myr.     

Tectonic vicariance versus Messinian dispersal in western Mediterranean ground beetles

The complex geological history of the western Mediterranean region conceals the interpretation of the evolutionary history of its current fauna, as similar distribution patterns may have very different temporal and geographic origins. Particularly intriguing are some subterranean species in islands, which origin is usually difficult to interpret as their strongly modified morphologies obscure their relationships. We studied subterranean taxa and their likely relatives of two groups of ground beetles in the western Mediterranean: the Duvalius lineage (“isotopic” Trechini) and Molopina (Pterostichini). We included specimens from the islands of Mallorca, Sardinia and Sicily, plus mainland Europe and North Africa. Phylogenetic relationships were reconstructed with a combination of mitochondrial and nuclear data, and divergence dates were estimated with Bayesian methods using the same a priori molecular evolutionary rates for the same gene fragments in the two groups. In the Duvalius lineage, the subgenus Trechopsis, including all the highly modified cave or nivicolous species, was found to be polyphyletic: the species from Mallorca was found to be of Pleistocene origin and sister to the less modified species of subgenus Duvalius from the same island, whereas the Algerian species of Trechopsis were, on the contrary, related to the Sicilian Duvalius, indicating a northern colonisation route during the late Pliocene. Molopina was divided into three main lineages: the genera Abax, Percus, and the Molops groups of genera. The basal diversification of the latter was dated within a temporal window (35–25 Ma) fully congruent with the tectonic opening of the western Mediterranean basin and included six main lineages with uncertain relationships among them: the epigean genera (a) Molops and (b) Tanythrix; and the subterranean (c) Typhlochoromus (Eastern Alps), (d) Speomolops (Sardinia), (e) Henrotius (Mallorca) and (f) a strongly supported clade including the Pyrenean genera Zariquieya, Oscadytes and Molopidius. Despite the similar distribution of some of their subterranean taxa, the two studied groups show a strongly contrasting origin and mode of diversification. While the Duvalius lineage had a recent origin, with complex colonisation patterns and widespread morphological convergence among the subterranean species, the subterranean Molopina had an ancient vicariant origin resulting from the tectonic opening of the western Mediterranean basin.     

Molecular phylogeny of Ceropegia (Asclepiadoideae, Apocynaceae) from Indian Western Ghats

Ceropegia includes more than 200 species distributed in the Old World ranging from the Canary Islands to Australia. In India, there are about 50 species described on a morphological basis as belonging to Ceropegia, and most of them are endemic to the Western Ghats. To investigate evolutionary relationships among Indian Ceropegia taxa and their allies, a phylogenetic analysis was conducted to include 31 Indian taxa of Ceropegia and Brachystelma and their congeners from other geographical regions using nuclear ribosomal internal transcribed spacer (ITS) and three noncoding chloroplast DNA (cpDNA) sequences, including intergenic spacers trnT-L and trnL-F, and trnL intron. The Western Ghats Ceropegia species were found to be most closely related to Indian Brachystelma, with the two genera being placed sister to each other in the ITS phylogeny or with the Brachystelma clade nested within one of the two subclades of Indian Ceropegia in the cpDNA phylogeny. In contrast, Ceropegia species from other regions and African Brachystelma all formed separate clades basal to the Indian Ceropegia–Brachystelma clade. Thus, it can be concluded that the classical morphology-based delineation of the two genera needs revision to reflect their phylogenetic relationships, which are more in accordance with their geographical origin than with morphology.     

The thoracic morphology of cave-dwelling and free-living ground beetles from China (Coleoptera,Carabidae, Trechinae)

External and internal thoracic structures of two carabid species (Trechini) were examined and documented with different techniques. The study has a main focus on the eyeless cave-dwelling specialist Sinaphaenops wangorum, but detailed information is also provided for a species occurring in cave entrances. The phylogenetic background of the structural features of the thoracic skeletomuscular system was addressed. The thoracic morphology of the examined species was compared to conditions observed in previously studied carabids and non-related subterranean leiodids (Staphylinoidea) in order to identify cave adaptations. Main thoracic character complexes linked with cavernicolous habits in Trechini are elongation of the pro- and mesothorax and the legs, and a complete and irreversible reduction of the flight apparatus. The lost flight capacity is linked with a far reaching modification of skeletal elements of the metathorax including a strongly shortened and simplified metanotum, a shortened metaventrite, and completely reduced wings and sclerites of the wing base. The elongate prothorax together with the long and slender head and elongated legs distinctly increases the activity range in the subterranean lightless environment, which likely facilitates foraging of the carnivorous beetles. Some of the observed features like wing loss and elongation of the anterior thorax and legs are also found in some cave-dwelling Leiodidae (Leptodirini), whereas some other subterranean members of the staphylinoid family have a compact body and legs of normal length. In contrast to the predaceous Trechini, Leptodirini are scavengers.     

Late Miocene diversification of the genus Hydrochus (Coleoptera, Hydrochidae) in the west Mediterranean area

We provide a reconstruction of the phylogenetic relationships, the geographical and temporal origin, and the mode of diversification of the Mediterranean species of the aquatic beetle family Hydrochidae (Coleoptera, Hydrophiloidea). A total of ca. 3KB of sequence data of three mitochondrial and two nuclear genes were used to reconstruct the phylogeny of 62 specimens of 21 species of Hydrochus, including all western Mediterranean species but one. We estimated the times of divergence using Bayesian methods and an evolutionary rate of 0.0115 substitutions/site/MY, and used an ultrametric calibrated tree to construct a Lineage Through Time (LTT) plot to test alternative models of diversification. A well resolved, well supported phylogeny showed that all western Mediterranean Hydrochus formed a clade, sister to a group including species with a central and eastern European distribution. The origin of the western Mediterranean clade was estimated to be at ca. 13MY, and the speciation events took place between this time and the end of the Messinian, at about 5.3MY. The LTT plot best fitted a model with a shift in the rate of diversification at ca. 8 MY, with a single speciation event (originating two Iberian endemics) subsequent to this period. We conclude that most of the western Mediterranean species of Hydrochidae, including the Ibero-Maghrebian endemics, are ancient elements likely to have remained in the same geographical area since their Miocene origin. Our results add to a growing body of evidence showing the importance of Mediterranean long-term, Tertiary refugia as both cradles and museums of diversity.     

DNA barcoding of genus Metapenaeopsis (Decapoda: Penaeidae) and molecular phylogeny inferred from mitochondrial and nuclear DNA sequences

Metapenaeopsis Bouvier, 1905 is the most diverse genus within Penaeidae. Metapenaeopsis shrimps exhibited subtle morphological differences, which make identification a difficult task based on taxonomic keys alone. In this study, we carried out DNA barcoding and phylogenetic analyses to examine taxonomy and phylogeny of genus Metapenaeopsis based on mitochondrial (COI) and nuclear (PEPCK and NaK) genes. Despite limited performance of DNA barcoding in delineating Metapenaeopsis shrimps, it questioned the taxonomic status of the two subspecies, Metapenaeopsis mogiensis intermedia and Metapenaeopsis mogiensis mogiensis, as well as three separate species: Metapenaeopsis provocatoria longirostris, Metapenaeopsis quinquedentata and Metapenaeopsis velutina. The major pattern of relationships between all studied taxa of Metapenaeopsis was similar across all analytical methods in which species with one-valved petasma were genetically distinct from those with two-valved petasma. As expected from morphology, the remaining species with stridulating organ constituted a strongly supported clade. In contrast, a paraphyletic clade was resolved for species without stridulating organ which contradicts Crosnier's morphological classification scheme for Metapenaeopsis. Overall, the present molecular data indicated that the shape of petasma and stridulating organ were both phylogenetically significant morphological characters for this genus, adding further evidence for the Crosnier's proposal.     

A molecular phylogenetic analysis of Speyeria and its implications for the management of the threatened Speyeria zerene hippolyta

The genetic structure of lineages can provide important information for delineating “evolutionarily significant units” (ESUs) for conservation, and for planning actions to protect and restore taxa threatened with extinction. Speyeria zerene hippolyta, the Oregon silverspot butterfly, is a U.S.A. federally threatened subspecies that is the focus of considerable conservation effort, but whose evolutionary relationships with other Speyeria taxa are not well-understood. We conducted a genetic analysis of nine Speyeria species and 25 subspecies from western U.S.A., using both mitochondrial and nuclear markers. Our goal was to determine whether such data supported (a) S. z. hippolyta’s designation as an ESU, and (b) the current morphologically-based taxonomy of Speyeria spp. Our data for S. z. hippolyta were equivocal; while nuclear markers resolved all these individuals into a single clade, mtDNA data suggested the existence of two clades. Aside from S. cybele, which was consistently supported as monophyletic, our data provided little support for most of the species currently recognized for western U.S. Speyeria, including S. zerene, and even less for the many subspecies designations. These genetic findings stand in contrast to the morphological differences recognized by experts, and suggest a relatively recent origin for many of these taxa. Two of 66 individuals screened for Wolbachia infection tested positive for this symbiont. Our results provide no persuasive evidence that S. z. hippolyta should lose its status as an ESU, but they have important implications for ongoing management actions such as population augmentation.     

Small-scale biogeographical patterns in some groundwater Crustacea, the syncarid, Parabathynellidae

An analysis was made of the micro-distribution patterns of five phylogenetically closely related species belonging to the genus Iberobathynella, a group of subterranean aquatic crustaceans (Syncarida, Parabathynellidae). The two-step model of colonization and speciation seems to provide a valid explanation for the current distribution of a large number of stygobiontic taxa of marine origin (thalassoid). However, with respect to the Iberobathynella, only the colonization of the subterranean environment at the mesoscale level can be explained. The second phase of the model, marine regression, can only explain the colonization of the region by the ancestor; the subsequent evolution and speciation at a smaller scale remain to be explained. Local geological constraints – Upper Triassic gypsiferous mudstone deposits plus faults and thrusting linked to the Alpine Orogeny – are responsible for the appearance of local palaeogeographic phenomena. These may have been the vicariant processes responsible for the geographical and genetic isolation of the ancestral populations of this group, which eventually led to clade divergence. Together with small-scale passive dispersion (11 dispersal events) and local extinction, these processes could be responsible for the current distribution of the five sister taxa inhabiting the caves of the Sierra de la Collada, Spain. A plausible palaeogeographical scenario is offered to explain their present distribution, that clearly came about through chance events.     

Evolutionary history of the Afro-Madagascan Ixora species (Rubiaceae): species diversification and distribution of key morphological traits inferred from dated molecular phylogenetic trees

Background and Aims

Previous work on the pantropical genus Ixora has revealed an Afro-Madagascan clade, but as yet no study has focused in detail on the evolutionary history and morphological trends in this group. Here the evolutionary history of Afro-Madagascan Ixora spp. (a clade of approx. 80 taxa) is investigated and the phylogenetic trees compared with several key morphological traits in taxa occurring in Madagascar.

Methods

Phylogenetic relationships of Afro-Madagascan Ixora are assessed using sequence data from four plastid regions (petD, rps16, rpoB-trnC and trnL-trnF) and nuclear ribosomal external transcribed spacer (ETS) and internal transcribed spacer (ITS) regions. The phylogenetic distribution of key morphological characters is assessed. Bayesian inference (implemented in BEAST) is used to estimate the temporal origin of Ixora based on fossil evidence.

Key Results

Two separate lineages of Madagascan taxa are recovered, one of which is nested in a group of East African taxa. Divergence in Ixora is estimated to have commenced during the mid Miocene, with extensive cladogenesis occurring in the Afro-Madagascan clade during the Pliocene onwards.

Conclusions

Both lineages of Madagascan Ixora exhibit morphological innovations that are rare throughout the rest of the genus, including a trend towards pauciflorous inflorescences and a trend towards extreme corolla tube length, suggesting that the same ecological and selective pressures are acting upon taxa from both Madagascan lineages. Novel ecological opportunities resulting from climate-induced habitat fragmentation and corolla tube length diversification are likely to have facilitated species radiation on Madagascar.     

Testing Species Delimitations in Four Italian Sympatric Leuciscine Fishes in the Tiber River: A Combined Morphological and Molecular Approach

Leuciscine fishes represent an important component of freshwater ichthyofauna endemic to northern Mediterranean areas. This lineage shows high intra-specific morphological variability and exhibits high levels of hybridization, two characteristics that contribute to systematic uncertainties, misclassification of taxa and, potentially, the mismanagement of biodiversity. This study focused on brook chub, Squalius lucumonis, an endemic taxon of Central Italy. The taxonomic status of this species has long been questioned, and a hybrid origin from sympatric leusciscines (S. squalus x Rutilus rubilio, or S. squalus x Telestes muticellus) has been hypothesised. A phenotypic (evaluating shape and meristic counts) and genetic (using mitochondrial and nuclear markers) investigation of these four taxa was conducted to test species delimitation in sympatric areas and to evaluate the taxonomic status of S. lucumonis. One hundred and forty-five individuals of all four taxa were collected within streams of the lowest portion of the Tiber River basin and analysed; this region encompasses a large portion of the S. lucumonis distribution. The different morphological and genetic approaches were individually examined, compared, and then combined in a quantitative model to both investigate the limits of each approach and to identify cases of misclassification. The results obtained confirm the cladogenetic non-hybrid origin of S. lucumonis, highlight the need for immediate conservation actions and emphasise the value of an integrated approach in the study of leuciscines evolution.     

Paraholcoglossum and Tsiorchis, two new orchid genera established by molecular and morphological analyses of the Holcoglossum alliance

Background

Holcoglossum is a small orchid genus of 12 species ranging from SW China to Thailand and NE India. Although molecular and morphological analyses have been performed to establish the phylogenetic relationships within this genus, the interspecific relations and its relations with allied genera, such as Rhynchostylis, Aerides and Vanda, remain unclear.

Methodology/Principal Findings

In addition to morphological analysis, maximum parsimony, maximum likelihood, and Bayesian inference analyses were performed based on fragments of the nuclear ITS and chloroplast trnL-F and matK genes of 31 taxa (15 Holcoglossum, 14 Aeridinae, 2 outgroups) representing all major clades of the Holcoglossum alliance. The results suggest that Holcoglossum is triphyletic, comprising three clades: the Holcoglossum clade, its sister clade, and a distant clade more closely related to Rhynchostylis, Aerides, and Vanda than to the Holcoglossum clade. The Holcoglossum clade is further divided into three subclades; the genetic distances between these three subclades also support this delimitation. The molecular conclusion is consistent with their distinct morphological characters.

Conclusions

We propose that the latter two clades comprise two new genera, Paraholcoglossum and Tsiorchis, and Holcoglossum clade divides into three sections. In addition, a new section, Holcoglossum sect. Nujiangensia, and a new species, Holcoglossum linearifolium, are proposed. Some new combinations are made, and a new scheme is provided for the classification of all species of Holcoglossum, Paraholcoglossum, and Tsiorchis.     

The phylogeny of the living and fossil Sphenisciformes (penguins)

We present the first phylogenetic analysis of the Sphenisciformes that extensively samples fossil taxa. Combined analysis of 181 morphological characters and sequence fragments from mitochondrial and nuclear genes (12S, 16S, COI, cytochrome b, RAG‐1) yields a largely resolved tree. Two species of the New Zealand Waimanu form a trichotomy with all other penguins in our result. The much discussed giant penguins Anthropornis and Pachydyptes are placed in two clades near the base of the tree. Stratigraphic and phylogenetic evidence suggest that some lineages of penguins attained very large body size rapidly and early in the clade's evolutionary history. The only fossil taxa that fall inside the crown clade Spheniscidae are fossil species assigned to the genus Spheniscus. Thus, extant penguin diversity is more accurately viewed as the product of a successful radiation of derived taxa than as an assemblage of survivors belonging to numerous lineages. The success of the Spheniscidae may be due to novel feeding adaptations and a more derived flipper apparatus. We offer a biogeographical scenario for penguins that incorporates fossil distributions and paleogeographic reconstructions of the Southern continent's positions. Our results do not support an expansion of the Spheniscidae from a cooling Continental Antarctica, but instead suggest those species that currently breed in that area are the descendants of colonizers from the Subantarctic. Many important divergence events in the clade Spheniscidae can instead be explained by dispersal along the paths of major ocean currents and the emergence of new islands due to tectonic events. © The Willi Hennig Society 2006.     

Congruence between comparative morphology and molecular phylogenies: the final stage of evolution of the skeletal characters of male genitalia in the subtribe polyommatina (Lepidoptera,Lycaenidae). Part 1. Valvae (distal part), aedeagus,and juxta

The evolution of the aedeagus, juxta, and microstructures on the valvae in the subtribe Polyommatina (Lycaenidae) during the last 5 MY is considered, and the chronology of morphological changes in these structures is established. The morphological characters of 47 species of the subtribe were tested by molecular analysis. Numerous cases of parallel evolution were discovered in the taxa of various taxonomic levels within Polyommatina. The principal shapes of the aedeagus apex developed independently in different clades. Multiple independent cases of an increase in the number of marginal denticles on the dorsal valvar clasps were observed in the genera Polyommatus, Plebejus, and Kretania. Parallel cases of a decrease in the number of these denticles were observed less frequently, in Aricia, Plebejus (P. argus), and Agriades (A. glandon). The juxta evolved from V- to U-shaped almost in all the clades. The rates of evolution of microcuticular and skeletal structures were shown to be different. For example, the number of cuticular denticles may change in 1 MY, while changes in the functionally important cuticular structures took as long as 2–3.5 MY. However, some structural changes were relatively fast; for instance, the club-shaped apex of the aedeagus was modified into a more typical conical form in less than 1 MY in species of the genus Agriades. Skeletal changes occurred in different moments of the evolutionary time frames of monophyletic species groups.     

Relationships within Podocarpaceae based on DNA sequence,anatomical, morphological,and biogeographical data

Despite considerable recent progress in understanding intergeneric relationships, a comprehensive analysis of Podocarpaceae at the species level using molecular data, biogeography, anatomy, and morphology has not been previously attempted. Here we present sequence analyses of rbcL, nrITS1 and NEEDLY intron 2 for two‐thirds (183 accessions of 145 taxa) of all Podocarpaceae species representing all genera except Parasitaxus. These analyses include many more species and accessions than previous studies and result in a more resolved phylogeny. The comprehensive anatomical and morphological study ensures that the identification of taxa is correct and also provides clade support. Bayesian and parsimony analyses were used to resolve 20 well‐supported monophyletic groups including 11 groups of the formerly poorly resolved subgenera Podocarpus and Foliolatus. The well‐resolved topology is supported by anatomical and morphological features and is highly congruent with geographical distribution. © The Willi Hennig Society 2011.     

Identification of a uniquely southern African clade of coastal pipefishes Syngnathus spp

The taxonomic status of two southern African coastal pipefish species, Syngnathus temminckii and Syngnathus watermeyeri, was investigated using a combination of morphological and genetic data. Morphological data showed that S. temminckii is distinct from the broadly distributed European pipefish Syngnathus acus, and a molecular phylogeny reconstructed using mitochondrial DNA recovered S. temminckii and S. watermeyeri as sister taxa. The southern African species share an evolutionary origin with north‐eastern Atlantic Ocean and Mediterranean Sea species, including S. acus. These data support the existence of a distinct southern African clade of Syngnathus pipefishes that has diverged in situ to form the two species present in the region today.     

Population Genetic Structure and Potential Incursion Pathways of the Bluetongue Virus Vector Culicoides brevitarsis (Diptera: Ceratopogonidae) in Australia

Culicoides brevitarsis is a vector of the bluetongue virus (BTV), which infects sheep and cattle. It is an invasive species in Australia with an assumed Asian/South East Asian origin. Using one mitochondrial marker (i.e., part of the cytochrome oxidase subunit I gene) and six nuclear markers, we inferred population genetic structure and possible incursion pathways for Australian C. brevitarsis. Nine mitochondrial haplotypes, with low nucleotide sequence diversity (0.0–0.7%) among these, were identified in a sample of 70 individuals from seven sites. Both sets of markers revealed a homogeneous population structure, albeit with evidence of isolation by distance and two genetically distinct clusters distributed along a north-to-south cline. No evidence of a cryptic species complex was found. The geographical distribution of the mitochondrial haplotypes is consistent with at least two incursion pathways into Australia since the arrival of suitable livestock hosts. By contrast, 15 mitochondrial haplotypes, with up to four times greater nucleotide sequence diversity (0.0–2.9%) among these, were identified in a sample of 16 individuals of the endemic C. marksi (sampled from a site in South Australia and another in New South Wales). A phylogenetic tree inferred using the mitochondrial marker revealed that the Australian and Japanese samples of C. brevitarsis are as evolutionarily different from one another as some of the other Australian species (e.g., C. marksi, C. henryi, C. pallidothorax) are. The phylogenetic tree placed four of the species endemic to Australia (C. pallidothorax, C. bundyensis, C. marksi, C. henryi) in a clade, with a fifth such species (C. bunrooensis) sharing a common ancestor with that clade and a clade comprising two Japanese species (C. verbosus, C. kibunensis).     

Phylogenetic relationships among Indriidae (Primates,Strepsirhini) inferred from highly repeated DNA band patterns

Comparative studies of highly repeated DNA from different species of Indriidae (Primates, Strepsirhini) allowed confirmation of the specific status of Avahi occidentalis, A. laniger and Propithecus tattersalli. The comparison of their band patterns revealed the existence of specific and common bands from which a cladogram of the family is inferred. This cladogram shows that Avahi clade is the sister-group of Indri and Propithecus clade, and that P. verreauxi is related to P. diadema. These results were discussed in view of those obtained from cytogenetic, morphological and molecular data (mitochondrial DNA). This study shows the capacity of the repeated sequence pattern comparison to be used as a tool for confirming taxa status, (taxinomic classification is a primary determinant of management priorities for endangered species, neglect of distinct taxa may lead to their extinction), and for inferring phylogenetic relationships among related species.     

Molecular Phylogeny of Weakfish Species of the Stellifer Group (Sciaenidae,Perciformes) of the Western South Atlantic Based on Mitochondrial and Nuclear Data

The phylogenetic relationships within the Stellifer group of weakfishes (Stellifer, Odontoscion, Ophioscion, and Bairdiella) were evaluated using 2723 base pairs comprising sequences of nuclear (rhodopsin, TMO-4C4, RAG-1) and mitochondrial (16S rRNA and COI) markers obtained from specimens of nine species. Our results indicate a close relationship between Bairdiella and Odontoscion, and also that the genus Stellifer is not monophyletic, but rather that it consists of two distinct lineages, one clade containing S. microps/S. naso/S. brasiliensis and the other, S. rastrifer/S. stellifer/Stellifer sp. B, which is closer to Ophioscion than the former clade. The O. punctatissimus populations from the northern and southern Brazilian coast were also highly divergent in both nuclear (0.8% for rhodopsin and 0.9% for RAG-1) and mitochondrial sequences (2.2% for 16S rRNA and 7.3% for COI), which we conclude is consistent with the presence of two distinct species. The morphological similarities of the members of the Stellifer group is reinforced by the molecular data from both the present study and previous analyses, which have questioned the taxonomic status of the Stellifer group. If, on the one hand, the group is in fact composed of four genera (Stellifer, Ophioscion, Odontoscion, and Bairdiella), one of the two Stellifer clades should be reclassified as a new genus. However, if the close relationship and the reduced genetic divergence found within the group is confirmed in a more extensive study, including representatives of additional taxa, this, together with the morphological evidence, would support downgrading the whole group to a single genus. Obviously, these contradictory findings reinforce the need for a more systematic taxonomic revision of the Stellifer group as a whole.     

Bony labyrinth morphometry indicates locomotor adaptations in the squirrel-related clade (Rodentia,Mammalia)

The semicircular canals (SCs) of the inner ear detect angular acceleration and are located in the bony labyrinth of the petrosal bone. Based on high-resolution computed tomography, we created a size-independent database of the bony labyrinth of 50 mammalian species especially rodents of the squirrel-related clade comprising taxa with fossorial, arboreal and gliding adaptations. Our sampling also includes gliding marsupials, actively flying bats, the arboreal tree shrew and subterranean species. The morphometric anatomy of the SCs was correlated to the locomotion mode. Even if the phylogenetic signal cannot entirely be excluded, the main significance for functional morphological studies has been found in the diameter of the SCs, whereas the radius of curvature is of minor interest. Additionally, we found clear differences in the bias angle of the canals between subterranean and gliding taxa, but also between sciurids and glirids. The sensitivity of the inner ear correlates with the locomotion mode, with a higher sensitivity of the SCs in fossorial species than in flying taxa. We conclude that the inner ear of flying and gliding mammals is less sensitive due to the large information flow into this sense organ during locomotion.     

Phylogeny of the North American catfish family Ictaluridae (Teleostei: Siluriformes) combining morphology,genes and fossils

We performed the first combined‐data phylogenetic analysis of ictalurids including most living and fossil species. We sampled 56 extant species and 16 fossil species representing outgroups, the seven living genera, and the extinct genus ?Astephus long thought to be an ictalurid. In total, 209 morphological characters were curated and illustrated in MorphoBank from published and original work, and standardized using reductive coding. Molecular sequences harvested from GenBank for one nuclear and four mitochondrial genes were combined with the morphological data for total evidence analysis. Parsimony analysis recovers a crown clade Ictaluridae composed of seven living genera and numerous extinct species. The oldest ictalurid fossils are the Late Eocene members of Ameiurus and Ictalurus. The fossil clade ?Astephus placed outside of Ictaluridae and not as its sister taxon. Previous morphological phylogenetic studies of Ictaluridae hypothesized convergent evolution of troglobitic features among the subterranean species. In contrast, we found morphological evidence to support a single clade of the four troglobitic species, the sister taxon of all ictalurids. This result holds whether fossils are included or not. Some previously published clock‐based age estimates closely approximate our minimum ages of clades.