Sister Group Research Articles

Morphological and molecular data suggest the presence of cryptic diversity within Dermacentor nitens (Acari: Ixodidae) in Colombia</p >

Of the 44 species within the genus Dermacentor (Acari: Ixodidae) worldwide, nine are found in the Neotropics and four are endemic to this region. In Colombia, located in the northwestern corner of South America, there are two species of the genus: Dermacentor imitans restricted to the trans-Andean Pacific region, and Dermacentor nitens widely distributed in the country. Elsewhere, D. nitens is found in both the Nearctic and Neotropics, from southern USA to northern Argentina. In the Neotropics, D. nitens is widely distributed including records in Caribbean islands. Molecular analyses of D. nitens collected in the Amazon region of Colombia have shown genetic differences with specimens from other localities of the country, although morphological differences have not been explored. We performed morphological and molecular comparisons of individuals from two natural regions of Colombia: the Orinoquia, and the Amazon. The morphological and morphometric results show that females and males are grouped in two morphotypes: morphotype I from the Orinoquia region, and morphotype II from Leticia in the Amazon region. The molecular analyses supported the morphological results and showed the formation of two well-differentiated sister clades within D. nitens, with divergences between both morphotypes of 3–4% and 5–6% for the 16S rRNA and COI genes, respectively. Species delimitation analyzes and the Poisson Tree Processes model tentatively suggest the presence of two species within the sequences associated with D. nitens in Colombia. The first represented by the sequences from the Orinoquia region evaluated here, together with sequences from other regions of Colombia and other Neotropical countries such as Brazil, Panama, and French Guiana. The second is represented by the sequences of individuals from Leticia, in the Amazon region of Colombia. The results highlight that D. nitens might represent a species complex, but further sampling, experimental crosses, and studies at the level of complete genomes should be performed to obtain additional evidence for species recognition.

The mitochondrial genome sequence of Ceratozetella imperatoria (Aoki, 1963) (Acari: Ceratozetidae): Genome characterization and phylogenetic analysis</p >

Oribatid mites play a crucial role in nutrient cycling, litter decomposition, and humus formation in the ecosystem. Here, an Illumina HiSeq platform was used to sequence the complete mitochondrial (mt) genome of Ceratozetella imperatoria. The mt genome is a circular molecule of 14,229 bp (GenBank number: PP419053), and a total of 37 genes were described. The start codon in all 13 protein-coding genes (PCGs) included ATT, ATA, TTG, and ATG, the stop codon of all 13 protein-coding genes was TAA, TAG, and single T. The AT skew and GC skew were 0.153 and 0.263 observed across the whole mt genome of Ceratozetella imperatoria. Besides the negative AT skew in PCGs, rRNA and CR, positive AT skew and GC skew were detected in the remaining components. A phylogenetic tree of 29 mite species was constructed using PCGs by the maximum likelihood method. Ceratozetoidea and Oripodoidea were closely related and become sister group relationships among them.

Anagenesis and the tyrant pedigree: A response to “Re-analysis of a dataset refutes claims of anagenesis within Tyrannosaurus-line tyrannosaurines (Theropoda, Tyrannosauridae)”

Taxonomic diversity in the derived tyrannosaurine Daspletosaurus has been hypothesized to represent a variety of evolutionary patterns by different authors. The recent description of D. wilsoni, the third species of this genus, was proposed to support the paraphyly of Daspletosaurus and participation of its species within a single anagenetic lineage terminating at the base of a clade formed by Tyrannosaurus and other gigantic tyrannosaurines (Tarbosaurus, Zhuchengtyrannus). However, a recent reanalysis including additional data has challenged this interpretation, instead recovering Daspletosaurus as a monophyletic sister group to Tyrannosaurus and its closest relatives, characterized by several cladogenetic events. Here we show that incorporating further data and correcting erroneous interpretations of relevant anatomical features overturns this result. Using a novel phylogenetic analysis including additional specimens, we recover a paraphyletic Daspletosaurus, with species of this genus forming successive sister taxa to Tyrannosaurus-line tyrannosaurines. This result facilitates an interpretation of currently recognized Daspletosaurus species as representing a single anagenetic lineage, in agreement with the stratigraphic distribution of relevant specimens and a qualitative analysis of the range of morphological variation observable within D. wilsoni.

Two new species of Hemidactylus Goldfuss, 1820 (Squamata: Gekkonidae) from the coastal areas of northern Somaliland

The taxonomy of many Hemidactylus geckos from the Horn of Africa has recently been evaluated. However, the lack of fresh material for some species and also regions has led to the misidentification of some taxa and an underestimation of the true diversity in others. In this study we analyse new material of Hemidactylus collected from poorly known coastal areas of northern Somaliland. Our results support the existence of two yet undescribed species within the arid clade. One of the new species is small-sized and closely related to H. afarensis from the Afar Triangle in Ethiopia, and together with two other species (H. foudaii, H. sinaitus) forms the monophyletic group for which we propose here the name sinaitus species group. The other new species is medium to large-sized, known from only one locality, and belongs to the macropholis species group, where it is a sister species of H. macropholis. Both new endemic species from the northern coastal hyper-arid plains highlight the role of northern Somaliland as an important biodiversity hotspot. Furthermore, our results show pronounced genetic diversity within H. macropholis, and imply possible existence of cryptic taxa within the species. Hemidactylus arnoldi and H. tropidolepis have, for the first time, been sequenced and placed in a phylogenetic context in this study. Our results confirm that H. tropidolepis is nested within the African radiation and is most closely related to H. funaiolii. Hemidactylus arnoldi clustered within the Arabian radiation of Hemidactylus and it was recovered as a sister lineage to all other species of the radiation.

Rapid Adaptation and Interspecific Introgression in the North American Crop Pest Helicoverpa zea.

Insect crop pests threaten global food security. This threat is amplified through the spread of nonnative species and through adaptation of native pests to control measures. Adaptations such as pesticide resistance can result from selection on variation within a population, or through gene flow from another population. We investigate these processes in an economically important noctuid crop pest, Helicoverpa zea, which has evolved resistance to a wide range of pesticides. Its sister species Helicoverpa armigera, first detected as an invasive species in Brazil in 2013, introduced the pyrethroid-resistance gene CYP337B3 to South American H. zea via adaptive introgression. To understand whether this could contribute to pesticide resistance in North America, we sequenced 237 H. zea genomes across 10 sample sites. We report H. armigera introgression into the North American H. zea population. Two individuals sampled in Texas in 2019 carry H. armigera haplotypes in a 4 Mbp region containing CYP337B3. Next, we identify signatures of selection in the panmictic population of nonadmixed H. zea, identifying a selective sweep at a second cytochrome P450 gene: CYP333B3. We estimate that its derived allele conferred a ∼5% fitness advantage and show that this estimate explains independently observed rare nonsynonymous CYP333B3 mutations approaching fixation over a ∼20-year period. We also detect putative signatures of selection at a kinesin gene associated with Bt resistance. Overall, we document two mechanisms of rapid adaptation: the introduction of fitness-enhancing alleles through interspecific introgression, and selection on intraspecific variation.

Bayesian phylogenetic analysis of Philippine languages supports a rapid migration of Malayo-Polynesian languages

The Philippines are central to understanding the expansion of the Austronesian language family from its homeland in Taiwan. It remains unknown to what extent the distribution of Malayo-Polynesian languages has been shaped by back migrations and language leveling events following the initial Out-of-Taiwan expansion. Other aspects of language history, including the effect of language switching from non-Austronesian languages, also remain poorly understood. Here we apply Bayesian phylogenetic methods to a core-vocabulary dataset of Philippine languages. Our analysis strongly supports a sister group relationship between the Sangiric and Minahasan groups of northern Sulawesi on one hand, and the rest of the Philippine languages on the other, which is incompatible with a simple North-to-South dispersal from Taiwan. We find a pervasive geographical signal in our results, suggesting a dominant role for cultural diffusion in the evolution of Philippine languages. However, we do find some support for a later migration of Gorontalo-Mongondow languages to northern Sulawesi from the Philippines. Subsequent diffusion processes between languages in Sulawesi appear to have led to conflicting data and a highly unstable phylogenetic position for Gorontalo-Mongondow. In the Philippines, language switching to Austronesian in ‘Negrito’ groups appears to have occurred at different time-points throughout the Philippines, and based on our analysis, there is no discernible effect of language switching on the basic vocabulary.

Ecological displacement in a Rocky Mountain hybrid zone informs management of North American martens (Martes)

ContextParapatric sister species are ideal for tests of ecological interactions. Pacific (Martes caurina) and American pine (M. americana) martens are economically and culturally valuable furbearers that hybridize in the north-central Rocky Mountains. Despite preliminary evidence of biased introgression, the hybrid zone has been geographically stable for 70 years, but interspecific ecological interactions have yet to be examined in detail.ObjectivesWe test whether ecological interactions may influence the outcome of hybridization in this system. To that end, we estimate the fundamental niche of each species and gauge how suitability landscapes change when the two species are in contact.MethodsWe genotyped > 400 martens from the Rocky Mountain hybrid zone to diagnose individuals to species-level and identify putative hybrids. We then built range-wide ecological niche models for each species, excluding individuals in the hybrid zone, to approximate their respective fundamental niches. Those models were projected into the hybrid zone and compared with niche models trained on individuals within the hybrid zone to assess how niche dynamics change when the species are in sympatry.ResultsThe fundamental niche of each species differed significantly, while the hybrid zone was equally suitable for both. Niches of each species based on models built within the hybrid zone showed that Pacific martens utilized significantly less suitable habitat than expected based on their range-wide fundamental niche, suggesting that species interactions shape local hybridization. We detected few admixed individuals (12%), with no evidence of directional (sex or species) biases. Interstate-90 further acts as a major dispersal barrier.ConclusionsNorth American martens are currently managed as a single species by some state agencies, yet significant ecological and genetic differences indicate they should be managed separately. The observed ecological displacement of Pacific martens by American pine martens may partially explain the mixed success of historical, mixed-species wildlife translocations and cautions such translocations in the future. Landscape-scale consideration of ecological dynamics, in addition to molecular compatibility, will be essential to the success of future translocations.

Mitochondrial genome analysis reveals phylogenetic insights and gene rearrangements in Parupeneus (Syngnathiformes: Mullidae)

Despite the critical role of mitochondrial genomes (mitogenomes) in species identification and evolutionary studies in the genus Parupeneus, current resources are inadequate, given the species richness. Although previous studies have suggested a complex evolutionary history, the detailed mitogenomic variations and their implications remain largely unexplored. Therefore, we sequenced and assembled the mitogenomes of P. barberinoides, P. barberinus, P. biaculeatus, P. crassilabris, P. cyclostomus, P. heptacanthus, P. multifasciatus, and P. chrysopleuron, to enrich the molecular data and provide novel insights into the genetic diversity, evolutionary dynamics and phylogenetics of the family Mullidae. Our analysis revealed a novel gene rearrangement in P. chrysopleuron, Cytb-T-P-CR-Q-I-F-12S-V-16S-ND1-M-ND2, which differed from the conventional sequence of Cytb-T-P-CR-F-12S-V-16S-ND1-I-Q-M-ND2 observed in other species. In the novel rearrangement, four non-coding regions are inserted between ND1 and M, Q and I, I and ψM (tRNA-Met pseudogene), ψM and F. We assume that two tandem duplication/random loss events occur in the CR and IQM, making the entire sequence longer than that in other Parupeneus species. The phylogenetic results indicated that Mullidae formed a sister group relationship with the family Dactylopteridae, contradicting previous studies that identified a sister group relationship between Mullidae and Callionymoidei. The genera Parupeneus and Mullus formed a sister group, and discrepancies were found in the topological structure of the interspecies relationships within the genus Parupeneus compared with those reported by previous studies. Through combined phylogenetic and mitochondrial structural analysis, we found that phylogenetic topology is closely related to mitochondrial structural abnormalities. This study not only expands the mitogenomic dataset available for Mullidae but also underscores the importance of mitochondrial DNA studies in resolving taxonomic ambiguities and understanding the evolutionary history of marine fishes. Our study contributes to the ongoing research on marine fish taxonomy, mitogenomics, and evolutionary biology by providing new insights into the genetic diversity of marine ecosystems.

Not so cryptic-differences between mating calls of Hyla arborea and Hyla orientalis from Bulgaria.

Anurans are among the most vocally active vertebrate animals and emit calls with different functions. In order to attract a mate, during the breeding season male frogs produce mating calls which have species-specific structure and parameters, and have been successfully used to resolve issues in taxonomy and phylogenetic relations. This is particularly useful when closely related taxa are concerned, as many species are morphologically almost identical, but still their status is well-supported by molecular and genetic data, suggesting the existence of mechanisms for reproductive isolation. Such is the case for treefrogs from the Hyla arborea group, which are now recognized as several distinct species. The present study aims to establish differences in call parameters between the European tree frog, Hyla arborea, and the Eastern tree frog, Hyla orientalis, which both occur on the territory of Bulgaria. Using autonomous audio loggers, calls from six sites (three in the range of H. arborea and three in the range of H. orientalis) were recorded between 7 p.m. and 12 a.m. during the breeding season in 2020-2023. The following parameters in a total of 390 mating calls were analyzed: call count, pulse count, call series duration, call period, peak (dominant) frequency, entropy. Results indicated that sites formed two distinct groups, which corresponded to the known distribution ranges of H. arborea and H. orientalis. The first two components of the PCA explained 71% of the total variance, with variables call count, call series duration, peak frequency and entropy being most important for differentiation between the sites. This study presents the first attempt to differentiate between the calls of these two sister taxa, which both fall within the "short-call treefrogs" group, and results are discussed in terms of known data for mating calls in Hyla sp., as well as limitations and future perspectives.

A new species of Pontocrates Boeck, 1871 (Crustacea, Amphipoda, Oedicerotidae) from Cyprus

A new species of the amphipod genus Pontocrates (Boeck 1871), family Oedicerotidae, is described from Cyprus in the south-eastern Mediterranean Sea. It is a sister taxon to Pontocrates moorei (Myers & Ashelby 2022), currently recorded solely from the British Isles. It is the third species of Pontocrates now known to occur in the Mediterranean Sea.

A new species in the Cyrtodactylus intermedius (Squamata: Gekkonidae) group from an isolated limestone karst formation in southwestern Cambodia

The gekkonid lizard Cyrtodactylus intermedius was formerly considered to be a single widespread species in hilly areas across eastern Thailand through southern Vietnam but has recently been partitioned into a complex of 12 nominal species across its range. A population belonging to the C. intermedius group was recently found in an isolated limestone karst block in Kampot Province in southwestern Cambodia, part of which lies within the recently designated Phnom Preah Kuhear Loung Natural Heritage Site. Comparisons of morphometric, meristic, qualitative morphological and color pattern data, as well as a molecular analysis using the mitochondrial ND2 gene, revealed that this population differs from all other named members of the C. intermedius group, and so is described here as a new species. The karst-dwelling C. regicavernicolus sp. nov. was recovered as the sister species to C. laangensis, the most geographically proximate member of the complex and one that is also restricted to a small limestone karst habitat.

The first Genetic data on <i>Lernaea Cyprinacea</i> Linnaeus, 1758 from the European North of Russia (The Pinega River)

Morphological and molecular genetic data about Lernaea cyprinacea Linnaeus, 1758, collected from pike (Esox lucius Linnaeus, 1758) in the European North of Russia (Pinega river) in 2022, were presented. Molecular genetic studies were carried out based on the analysis of COI mtDNA, 18S rDNA and 28S rDNA gene sequences. A significant genetic distance for the COI gene from individuals of the same species collected in other territories (China, Australia, South Africa, Canada, Austria, Argentina, Pakistan, Iran, India, Japan, Romania, Egypt and Western Siberia) was revealed, which indicates the existence of a cryptic species L. cyprinacea in the European North of Russia. Analysis of 28S rDNA sequences showed the presence of two substitutions fixed in the population, which may indicate a fairly long-standing divergence of sister species. The 18S rDNA gene fragment is less suitable for identifying L. cyprinacea due to low variability compared to the other two gene regions.

Stiphodon chlorestes, a new species of sicydiine goby (Teleostei: Gobioidei) from Taiwan and Luzon.

Stiphodon chlorestes sp. nov. is described based on seven specimens collected from Taiwan and Luzon. It is a large-sized Stiphodon species sharing the second dorsal-fin rays 9-10 and pectoral-fin rays 14-16 with similar-sized congeners. However, it differs from them by the wider interorbital width and almost complete lack of scales on the occipital region in males. In addition, the new species can be further distinguished from all congeners by seven to eight oval bands or a black longitudinal band on the lower body, black and white spots on pectoral fins, and a short red or orange line on posterior upper edge of caudal fin. Molecular analysis based on the 680-bp mitochondrial cytochrome oxidase subunit I (COI) fragments also supports it as a distinct species belonging to the "Stiphodon elegans group" and a sister group of the clade consisting of Stiphodon multisquamus and Stiphodon palawanensis.

Complete Mitochondrial Genome and Phylogenetic Analysis of the Blue Whistling Thrush (Myophonus caeruleus).

The blue whistling thrush (Myophonus caeruleus) is a bird belonging to the order Passeriformes and family Muscicapidae. M. caeruleus is widely distributed in China, Pakistan, India, and Myanmar and is a resident bird in the southern part of the Yangtze River in China and summer migratory bird in the northern part of the Yangtze River. At present, there are some controversies about the classification of M. caeruleus. We use complete mitochondrial genomes to provide insights into the phylogenetic position of M. caeruleus and its relationships among Muscicapidae. The mitochondrial genome (GenBank: MN564936) is 16,815 bp long and contains 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes, and a non-coding control region (D-loop). The thirteen PCGs started with GTG and ATG and ended with five types of stop codons. The nucleotide composition of T was 23.71%, that of C was 31.45%, that of A was 30.06%, and that of G was 14.78%. The secondary structures of 22 tRNAs were predicted, all of which could form typical cloverleaf structures. There were 24 mismatches, mainly G-U mismatches. Through phylogenetic tree reconstruction, it was found that Saxicola, Monticola, Oenanthe, and Phoenicurus were clustered into one clade, together with the sister group of Myophonus.

The effectiveness of selection in a species affects the direction of amino acid frequency evolution.

Nearly neutral theory predicts that species with higher effective population size (N e ) are better able to purge slightly deleterious mutations. We compare evolution in high-N e vs. low-N e vertebrates to reveal which amino acid frequencies are subject to subtle selective preferences. We take three complementary approaches, two measuring flux and one measuring outcomes. First, we fit non-stationary substitution models of amino acid flux using maximum likelihood, comparing the high-N e clade of rodents and lagomorphs to its low-N e sister clade of primates and colugos. Second, we compare evolutionary outcomes across a wider range of vertebrates, via correlations between amino acid frequencies and N e . Third, we dissect the details of flux in human, chimpanzee, mouse, and rat, as scored by parsimony - this also enables comparison to a historical paper. All three methods agree on which amino acids are preferred under more effective selection. Preferred amino acids tend to be smaller, less costly to synthesize, and to promote intrinsic structural disorder. Parsimony-induced bias in the historical study produces an apparent reduction in structural disorder, perhaps driven by slightly deleterious substitutions. Within highly exchangeable pairs of amino acids, arginine is strongly preferred over lysine, and valine over isoleucine, consistent with more effective selection preferring a marginally larger free energy of folding. These two preferences match differences between thermophiles and mesophilic relatives. These results reveal the biophysical consequences of mutation-selection-drift balance, and demonstrate the utility of nearly neutral theory for understanding protein evolution.

A comprehensive phylogenetic analysis on early ornithischian evolution

Resolving the evolutionary relationships of early diverging (‘basal’) ornithischian dinosaurs is a challenging topic in palaeontology, with multiple competing hypotheses on the phylogenetic relationships of heterodontosaurids, ‘hypsilophodontids’, and other early-diverging forms. These hypotheses cannot be directly compared because they are derived from differently constructed datasets (i.e. distinct samples of taxa and characters). This study aims to address these issues by revising and combining the distinct datasets into a single analysis in order to create the most comprehensive dataset for the investigation of the phylogenetic relationships of early-diverging ornithischians. A diphyletic model of Dinosauria is supported, with silesaurs nesting as members of Ornithischia. Heterodontosauridae is resolved as a clade of non-genasaurian ornithischians, rejecting a potential relationship with Marginocephalia. ‘Hypsilophodontid’ taxa span the neornithischian and ornithopod stem, with Thescelosauridae as the sister taxon to Cerapoda. A more restricted Ornithopoda is composed of five main clades: Hypsilophodontidae, Rhabdodontomorpha, Elasmaria, Dryosauridae and Ankylopollexia. Hypsilophodontidae is a valid clade, reduced to two European Barremian taxa. Rhabdodontomorpha does not contain Muttaburrasaurus as originally proposed, but instead expands to include a North American clade formed by Convolosaurus, Iani and Tenontosaurus. Elasmaria contains all non-dryomorph Gondwanan ornithopods, with its members possessing multiple distinct body plans. New results and comparison with previous studies suggest that some members of Dryosauridae are not ‘true dryosaurids’ but various early euiguanodontians that may be more closely related to either Elasmaria or Ankylopollexia. Results group most ‘hypsilophodontids’ in larger clades, significantly reducing the number and extension of ghost lineages throughout all of Neornithischia. These clades also show a degree of endemism, with different lineages present at different continents in the Late Cretaceous. This new phylogenetic analysis unifying previous works will provide a framework for future studies on origins and relations of early diverging ornithischians, and attempting to find stability among the different competing hypotheses.

The Complete Chloroplast Genome of an Epiphytic Leafless Orchid, Taeniophyllum complanatum: Comparative Analysis and Phylogenetic Relationships

Taeniophyllum is a distinct taxon of epiphytic leafless plants in the subtribe Aeridinae of Orchidaceae. The differences in chloroplast genomes between extremely degraded epiphytic leafless orchids and other leafy orchids, as well as their origins and evolution, raise intriguing questions. Therefore, we report the chloroplast genome sequence of Taeniophyllum complanatum, including an extensive comparative analysis with other types of leafless orchids. The chloroplast genome of T. complanatum exhibited a typical quadripartite structure, and its overall structure and gene content were relatively conserved. The entire chloroplast genome was 141,174 bp in length, making it the smallest known chloroplast genome of leafless epiphytic orchids. It encoded a total of 120 genes, including repetitive genes, comprising 74 protein-coding genes, 38 transfer RNA (tRNA) genes, and 8 ribosomal RNA (rRNA) genes. A phylogenetic analysis was conducted on the chloroplast genomes of 43 species belonging to five subfamilies of Orchidaceae. The results showed that the five subfamilies were monophyly, with nearly all segments having a 100% bootstrap value. T. complanatum and Chiloschista were clustered together as a sister group to Phalaenopsis and occupied the highest position in the Epidendroideae. Phylogenetic analysis suggested that T. complanatum and other leafless orchids within the Orchidaceae evolved independently. This study may provide the foundation for research on phylogenetic and structural diversity in leafless epiphytic orchids, thereby enhancing the resources available for chloroplast genome studies in Orchidaceae.

A new species of direct-developing frog of the genus Eleutherodactylus (Anura: Eleutherodactylidae) from Tamaulipas, Mexico

The number of species of the subgenus Syrrhophus, genus Eleutherodactylus has increased rapidly in the last eight years, due to recent taxonomic studies. This subgenus of direct-developing frogs is well represented in Mexico, which harbors more than 90% of the species richness reported for the subgenus. In this study, we describe one new species, Eleutherodactylus (Syrrhophus) coelum sp. nov. from the El Cielo Biosphere Reserve in Tamaulipas, Mexico, based on morphological and molecular data. The new species, which was previously assigned to E. cystignathoides, differs from its congeners mainly by its small size and by having the tips of Finger III and IV expanded to twice the width of the narrowest part of these fingers. Phylogenetic analyses recovered a well-supported relationship of the new species as the sister group to an undescribed taxon from San Luis Potosí. This analysis also indicates there are more lineages wating for description.

Structure and Phylogenetic Relationships of Scolopacidae Mitogenomes (Charadriiformes: Scolopacidae).

The family Scolopacidae presents a valuable subject for evolutionary research; however, molecular studies of Scolopacidae are still relatively understudied, and the phylogenetic relationships of certain species remain unclear. In this study, we sequenced and obtained complete mitochondrial DNA (mtDNA) from Actitis hypoleucos and partial mtDNA from Numenius arquata, Limosa limosa, and Limnodromus semipalmatus. The complete mtDNA contained 13 protein-coding genes (PCGs), two ribosomal RNA genes, 22 tRNA genes, and a control region. Scolopacidae contained three types of start codons and five types of stop codons (including one incomplete stop codon, T--). In 13 protein-coding genes, average uncorrected pairwise distances (Aupd) revealed that ATP8 was the least conserved while COX3 had the lowest evolutionary rate. The ratio of Ka/Ks suggested that all PCGs were under purifying selection. Using two methods (maximum likelihood and Bayesian inference) to analyze the phylogenetic relationships of the family Scolopacidae, it was found that the genera Xenus and Actitis were clustered into another sister group, while the genus Phalaropus is more closely related to the genus Tringa. The genera Limnodromus, Gallinago, and Scolopax form a monophyletic group. This study improves our understanding of the evolutionary patterns and phylogenetic relationships of the family Scolopacidae.

Morphology and systematics of a new fossil snake from the early Rupelian (Oligocene) White River Formation, Wyoming

Abstract Extinct snake taxa are recognized primarily from isolated vertebrae. A new specimen from the early Oligocene of Wyoming provides a rare opportunity to examine four nearly complete and articulated fossil snakes. Informally assigned previously to the ‘erycine’ vertebral form taxa Ogmophis and Calamagras, a detailed comparison reveals that this fossil snake exhibits vertebral differences from both taxa and is, furthermore, a new taxon, Hibernophis breithaupti gen. et sp. nov., based on a combination of apomorphies such as absence of basal tubera, low subrectangular prootic, low parasphenoid wings obscuring the anterior opening of the Vidian canal, and foramen for the mandibular branch of the trigeminal nerve posteriorly displaced inside the adductor fossa of the compound. Parsimony and Bayesian phylogenetic analysis of combined morphological and molecular data from a broad selection of snakes places Hibernophis breithaupti as sister taxon to all other booids, distant from both Old and New World ‘erycines’. However, an alternative position close to New World ‘erycines’ and ungaliophiines cannot be rejected.