Argyrolagus and its closest relatives (Argyrolagidae; Late Eocene or Early Oligocene-Early Pleistocene) are usually regarded as outliers among marsupials, with many peculiar craniodental and postcranial features that differ considerably from those found in other recognized groups of metatherians. In the literature this factor has led to variant interpretations of basic anatomical features that usually present no difficulty in identification, like eye position and location of some neurovascular foramina. To shed light on these and other unresolved morphological issues, we report here on new and previously described cranial material of Argyrolagus using modern methods (mu CT scanning, morphometrics). Argyrolagus was a small taxon (between 60 g to 150 g body mass) with an elongated, projecting rostrum convergently resembling that of the rodents Dipodomys and Sommeromys, or Rhynchocyon and Elephantulus among elephant shrews. Contrary to some reconstructions, but in line with G.G. Simpson's original interpretation, the orbit of Argyrolagus was most likely located in the caudal half of the cranium, and was large (similar to 9 mm) for its projected body size. The origin of the temporalis muscle, also disputed, appears to have been small and lain on the caudal part of the cranium above the external acoustic meatus. Orbital convergence was low while the angle of orbital verticality was high, indicating panoramic vision. Three-dimensional reconstruction and interpretation of the auditory region (including the tympanic membrane, middle ear ossicles, middle ear volume, inner ear) indicates that hearing in Argyrolagus favored low frequencies. This correlates with hearing capabilities of extant small mammals (mostly rodents) that live in open environments and/ or inhabit underground tunnels. Both interpretations seem plausible considering the paleoenvironments in which Argyrolagus is thought to have lived. Other features, like the cranial circulatory system, appear to be a mosaic of primitive (e.g., small internal jugular vein, most cranial return through external jugular) and derived features (e.g., absence of proximal stapedial artery, absence of postglenoid vein, and a venous arrangement analogous to the sinus communicans found in some placentals). Although some authors have wondered whether argyrolagoids were metatherians or even therians, our reinterpretation of salient anatomical features in Argyrolagus is consistent with their closest affinities being metatherian, as exemplified by absence of an independent optic canal, lack of proximal stapedial artery, enhanced pericarotid system, and inflected angle of dentary, although their precise systematic placement remains elusive.
At least four subfamily-level clades of mosasaurs are broadly recognized (Mosasaurinae, Plioplatecarpinae, Tylosaurinae, Halisaurinae), each of which independently evolved flippers and other aquatic adaptations, including large body size. Tylosaurine mosasaurs are distinguished from other mosasaurs, in part, by edentulous extensions of both upper and lower jaws, proportionally long tails, and poorly ossified limbs, and they were the first mosasaur clade to achieve gigantic (>8 m) body size. Several tylosaurine species are known from Europe, Asia, New Zealand, Africa, and Antarctica, but they were most common in the Western Interior Seaway of North America. Here, we describe a new species, Tylosaurus rex, sp. nov., from the Campanian of Texas and analyze tylosaurine ingroup systematics using a significantly updated phylogenetic character list. Our new species is distinguished by a unique suite of characters, including some associated with increased jaw and neck musculature, and others that may be convergent with other giant mosasaur species (e.g., Mosasaurus). Body length estimates for specimens referred to our new species are consistently larger (7.7-13.2 m) than those for the largest Niobrara species, T. proriger (3.9-9.5 m), although it is unclear whether this is a taxonomic signal or taphonomic bias. Several specimens that we refer to T. rex were previously referred to T. proriger in various collections databases, and some of the traits distinguishing them had been previously attributed to ontogenetic differences. However, we rule out this possibility as specimens of T. proriger and T. rex that do overlap in size can be differentiated by unique suites of diagnostic characters. The implicit association between body size and ontogeny, as well as the general absence of reliable locality and stratigraphic data associated with historical collections of North American mosasaurs, raises the possibility of the presence of other currently unrecognized species, previously dismissed as ontogenetic stages of other species.
Ricinulei Thorell, 1876, or "hooded tick-spiders," are an ancient, relictual, and cryptic order of arachnids comprising 104 extant species traditionally accommodated in three genera. Although six phylogenetic hypotheses have been proposed to date (Platnick, 1980; Selden, 1992; Murienne et al., 2013; Fern & aacute;ndez and Giribet, 2015; Benavides et al., 2021; Sato et al., 2024), the relationships among the three currently recognized genera of Ricinulei remain unresolved and the monophyly of both New World genera has been questioned. The first quantitative intraordinal phylogeny of Ricinulei based on morphology is presented, focusing on the African taxa, currently assigned to the genus Ricinoides Ewing, 1929, and selected exemplar species of the New World genera, Cryptocellus Westwood, 1874, and Pseudocellus Platnick, 1980, as outgroups. The character matrix, comprising 80 discrete characters scored for 27 species, was analyzed with parsimony and Maximum Likelihood. A preferred topology, corresponding to the consensus of three optimal trees, the stability of which was insensitive to a range of weighting regimes, is presented. This topology recovered the African Ricinulei as monophyletic, in turn forming a monophyletic group with Cryptocellus, to the exclusion of Pseudocellus. Although this hypothesis of ricinuleid intraordinal relationships differs from the hypotheses obtained by molecular phylogenetic analyses, it is consistent with the sequence of vicariance events resulting from the breakup of Pangaea (ca. 200-180 Ma), which separated Pseudocellus from all other ricinuleids, and Gondwana (ca. 140-120 Ma), which separated Cryptocellus from the African Ricinulei. Due to the high levels of morphological divergence among the clades recovered by the analysis, Ricinoides is redefined and restricted to nine species from C & ocirc;te d'Ivoire, Ghana, Guinea, Guinea-Bissau, Nigeria, Sierra Leone, and Togo, but also present in the Gambia and Senegal, and five new genera are defined: Alantakun, gen. nov., comprising a single species from Cameroon, Congo, Equatorial Guinea, and Gabon; Bambara, gen. nov., comprising three species from C & ocirc;te d'Ivoire, Guinea, and Sierra Leone, but also present in Liberia; Gizoo, gen. nov., comprising a single species from Cameroon and Equatorial Guinea (Bioko Island); Tautau, gen. nov., comprising two species from Guinea and Sierra Leone, but also present in C & ocirc;te d'Ivoire; and Ududo, gen. nov., comprising two species from Cameroon and Nigeria. Six new combinations are presented: Alantakun karschii (Hansen and S & oslash;rensen, 1904), comb. nov.; Bambara hanseni (Legg, 1976), comb. nov.; Bambara megahanseni (Legg, 1982), comb. nov.; Gizoo crassipalpe (Hansen and S & oslash;rensen, 1904), comb. nov.; Tautau leonensis (Legg, 1978), comb. nov.; and Ududo sjostedtii (Hansen and S & oslash;rensen, 1904), comb. nov. Three new species are described and illustrated: Bambara jocquei, sp. nov., and Tautau ziama, sp. nov., both from Guinea, and Ududo tuxeni, sp. nov., from Nigeria. A new synonym is presented: Ricinoides olounoua Legg, 1978 = Alantakun karschii (Hansen and S & oslash;rensen, 1904), syn. nov. Revised diagnoses are provided for all other African species. In all, six genera and 18 species of Ricinulei are presently recorded from 14 African countries. A key to the identification of the African genera and species is presented, as well as maps plotting their known distributions. The male copulatory apparatus of the African species is studied and six "types" are recognized. Morphological characters useful for the classification and identification of African Ricinulei, are illustrated.
Morphology continues to have a central role in systematics and taxonomy, especially regarding the positioning of fossil taxa in the Tree of Life and as an independent source of information to evaluate competing molecular phylogenetic hypotheses. For the stingless bees, morphology and behavior were the only sources of information about their systematics and biogeography for an extended period. Currently, Meliponini is a group with relatively well-known evolutionary relationships in comparison with other bee tribes. However, there are strong incongruences between morphological and molecular results and little progress has been made to reassess the morphological evidence and its role in our understanding of their evolutionary history. Considering this background, the present study intends to take a step further toward understanding the role of morphology in the context of evolutionary relationships among stingless bees. We built a matrix of 375 characters coded for representatives of all extant genera and subgenera of Meliponini. We also included information about the fossil tribe dagger Melikertini and dagger Proplebeia dominicana in parsimony and Bayesian analyses. Results changed according to the optimality criterion and weighting (or partitioning) scheme adopted as well as assumptions regarding outgroups. We demonstrate that the tribe dagger Melikertini, known only from extinct taxa, is strongly supported as the closest relative of the stingless bees. The phylogenetic position of the Miocene fossil dagger Proplebeia dominicana is evaluated and was consistent among all analyses. Morphological evidence shed light on incongruences found in previous phylogenomic analyses, showing that morphology can represent an essential source of evidence to increase our confidence concerning competing hypotheses. A morphological characterization of major clades is provided and synapomorphies are discussed. We argue that combining morphological, chronological, and molecular evidence will be essential for unraveling the complex biogeographic history of stingless bees.
The Palearctic buthid scorpion genus Buthus Leach, 1815, distributed from southwestern Europe (southern France and the Iberian Peninsula) across Africa north of the Sahara, to the Levant and the Arabian Peninsula, has undergone extensive taxonomic revision in the past two decades. Despite these efforts, its taxonomic composition remains confused, perhaps nowhere more so than in the Iberian Peninsula, where 20 putative species were recognized in the past two decades. Molecular phylogenetic studies of Buthus in northwestern Africa and southwestern Europe, based on a few, mostly mitochondrial gene loci, recovered a monophyletic origin for the European clade of Buthus and suggested the existence of several distinct lineages on the Iberian Peninsula. However, relationships with the species of Buthus from the North African Maghreb remained ambiguous. Morphological descriptions of new or revalidated species of Buthus, based in part on the molecular phylogenies but lacking robust diagnoses, and making little attempt to consider geographical variation, compounded the confusion. The present contribution provides a comprehensive, integrative revision of the European species of Buthus based on samples, including topotypes, collected across the known distribution, rigorous phylogenetic analyses combining morphology, nuclear and mitochondrial DNA sequences, morphometric analyses, and ecological data. Nine valid species of Buthus are recognized across France, Portugal, and Spain, and 10 new synonyms presented: Buthus delafuentei Teruel and Turiel, 2020 = Buthus gonzalezdelavegai Gonz & aacute;lez-Molin & eacute; and Armas, 2024, syn. n.; Buthus elongatus Rossi, 2021; Buthus garcialorcai Teruel and Turiel, 2020; Buthus halius (C.L. Koch, 1839) = Androctonus ajax C.L. Koch, 1839, syn. n. = Buthus gabani Ythier, 2021, syn. n. = Buthus castellano Teruel and Turiel, 2022, syn, n.; Buthus iaspis Teruel and Turiel, 2022; Buthus ibericus Louren & ccedil;o and Vachon, 2004 = Buthus baeticus Teruel and Turiel, 2020, syn. n.; Buthus manchego Teruel and Turiel, 2020 = Buthus alacanti Teruel and Turiel, 2020, syn. n. = Buthus serrano Teruel and Turiel, 2020, syn. n. = Buthus pedrosousai Teruel and Turiel, 2021, syn. n.; Buthus montanus Louren & ccedil;o and Vachon, 2004; Buthus occitanus (Amoreux, 1789) = Buthus pyrenaeus Ythier, 2021, syn. n. = Buthus balmensis Ythier and Laborieux, 2022, syn. n. Revised, comparative diagnoses and illustrations are provided for each species, together with a distribution map and key to their identification.
Eurypterids, also known as sea scorpions, were aquatic chelicerate arthropods that were important components of Paleozoic marine and freshwater ecosystems from the Ordovician to the Permian. The group represents an excellent subject for studies into evolution due to their exceptionally preserved fossils which frequently reveal almost complete details of the exoskeleton, including the appendages, which allows for interpretation of their roles in ancient ecosystems. This contribution presents an overview of the 200-year history of eurypterid research and their occurrence in popular media before presenting an updated classification for Eurypterida based on concordant parsimony and Bayesian phylogenetic analyses of 238 morphological characters coded for 152 species. This represents the first comprehensive treatment of eurypterid systematics in 35 years and includes evaluation of every known described species of eurypterid. In the process several species names occurring in the Russian literature are shown to be invalid. The appropriate taxonomic authorities for Eurypterida, Stylonurina, and Eurypterina are revised and a revision conducted of all known species. Eighteen new taxa are proposed; the superfamily Waeringopteroidea, the families Brachyopteridae, Stylonurellidae, Strobilopteridae, Waeringopteridae, Nanahughmilleriidae, Parahughmilleriidae, Pittsfordipteridae, Ciurcopteridae, Herefordopteridae, and Hunanopteridae, and the genera Athenepterus, Waterstonopterus, Barusopterus, Cruinnopterus, Selkiepterella, and Hunanopterus. The species name Strobilopterus proteus is also formally made available for the first time. Eurypterid anatomical terminology is updated and standardized. Reviewing previous analyses of macroevolutionary and macroecological trends within eurypterids in light of the revised relationships suggested here indicates that their conclusions are still generally supported, although the history of eurypterid geographic occurrence and dispersal is more complicated than previously considered. Recent discoveries of eurypterids from the paleocontinent of Gondwana represent some of the more exciting new developments in eurypterid research and it is likely that more eurypterids will be found in these regions in the future. Ongoing research into eurypterid ontogeny and macroevolution is detailed and understudied aspects of eurypterid paleobiology, including their ichnological record, role in paleocommunities, and taphonomy are explored. Suggestions are made for inroads into these relatively neglected research programs. Common misconceptions about eurypterids are also addressed; no eurypterid is known to possess a venomous sting in its tail, and while eurypterids likely congregated to shed their exoskeletons there is no compelling evidence that they mated en masse.
A new genus and species of extant shrew, Nagasorex albidens, is described based on a single specimen obtained in Nagaland, northeastern India, in 1950. The new species shows novel characters, such as a total tooth number of 34, not found in any extant genus though they are found in extinct genera such as dagger Miosorex, dagger Lartetium, dagger Pseudotrimylus, and dagger Domnina. To determine the phylogenetic relationships of the new species, we first analyzed craniodental characters from all extant and many extinct genera of Soricidae. Although statistical support for most nodes was low, the nearest relatives of the new taxon appear to be certain Miocene and Pliocene taxa from Europe and Asia-dagger Dobenflorinia (new name), dagger Clapasorex, dagger Miosorex, and dagger Crocidosorex-followed by the extant African genera Congosorex, Myosorex, and Surdisorex, all of which we treat as members of the Myosoricinae. We then conducted a molecular phylogenetic study of extant genera using mitochondrial and nuclear genes. Although the genetic data we obtained from the new shrew are limited, our results place Nagasorex as the sister taxon of Crocidurinae (mitochondrial genes), or sister to Myosoricinae + Crocidurinae (nuclear genes). We tentatively place the new genus in the Myosoricinae. Additionally, we replace the preoccupied generic name Soricella with a new name, Dobenflorinia. Based on these results, we present a new systematic arrangement of the Soricidae.
Wyolestes is an extinct placental mammal from early Eocene (Wasatchian) rocks of North America whose phylogenetic position has been enigmatic for decades. Known from three species with distinct, high-cusped molars, the genus has been difficult to assign to a higher clade within Placentalia in part because it has, until now, been known primarily from dentitions. Here we describe new postcranial material of Wyolestes iglesius; new cranial, dental, and postcranial material, including both axial and appendicular elements, of W . apheles; and new postcranial and dental material of W . dioctes. Examining the phylogenetic position of Wyolestes in a character-dense, total evidence matrix that sampled extant and extinct taxa across Mammalia, reveals that Wyolestes is the sister taxon of the hyaenodont Sinopa, a clade we refer to here as Hyaenodonta. This finding revives a phylogenetic attribution first proposed by Gazin over 60 years ago. Wyolestes is phylogenetically distant from both mesonychids and didymoconids, a result with strong jackknife support. The hyaenodont clade is sister to Carnivoraformes and nested within Ferae. Inclusion of Wyolestes in a more focused phylogenetic analysis with dense sampling of early Ferae supports placement of Wyolestes within Hyaenodonta. A third analysis of early hyaenodonts indicates that the two Wyoming species, W . apheles and W . dioctes are sister taxa with respect to the Baja California species, W . iglesius. Skull material of W . apheles indicates the first known presence of an ossified tentorium cerebelli in Wyolestes, a fragile feature whose preservation is significant because it has been cited as a synapomorphy of Ferae, and is known in Carnivora, Pholidota, and their fossil relatives as well as in Hyaenodonta. The postcranial skeleton reveals that Wyolestes was a relatively generalized Paleogene mammal. Body mass estimates using extant Carnivora as an analog indicate that all species of Wyolestes weighed less than 10 kg and two species less than 5 kg. Wyolestes lacked derived climbing abilities. Nor does the postcranial skeleton indicate that it was semifossorial, but it suggests it may have had more of a tendency toward scratch digging. The postcranial skeletons exhibit many generalized features such as a deltopectoral crest that extends at least halfway down the shaft of the humerus, and the presence of an entepicondylar foramen, as well as the likely presence of a centrale in the manus. For skeletal elements that can be directly compared, such as the humerus, W . apheles is more robust than W . iglesius. Dental morphology indicates a sister taxon relationship between W . apheles and W . dioctes to the exclusion of W . iglesius.
Amazonia is a great natural laboratory, allowing the study of complex evolutionary mechanisms that promote diversification associated with dynamic geomorphological, climatic, and ecological processes, which often generate fuzzy species boundaries. We investigated the evolutionary history of two sister species of nurse frogs distributed in northwestern Amazonia, Allobates insperatus and A. juami, which have been considered as different entities based on molecular evidence, despite the absence of substantial phenotypic differences. We obtained morphological, osteological, and acoustic data, and DNA sequences of one mitochondrial and six nuclear gene fragments across the species distribution. The mitochondrial tree and species delimitation methods suggest the existence of at least four main evolutionary lineages; however, the signal of the nuclear markers is discordant among some groups, showing the admixture of those lineages that may reflect introgression and/or incomplete lineage sorting. Considering all sources of evidence, we confirm A. insperatus and A. juami as valid species and redescribe the former. In addition, we recognize and describe a new species supported by all data and analyses. Our findings suggest that speciation of Allobates, and perhaps of other sympatric anurans, in western Amazonia may have been influenced by the Pebas megawetland, with subsequent dispersion through the Andean foothills before the formation of the main Amazonian rivers, followed by colonization of the emerging northwestern Amazonian lowlands and secondary contact of newly diverged sister lineages.
For four decades after 1967, four species of nurse frogs were recognized in the Atlantic Forest, namely Allobates alagoanus (Bokermann, 1967), A. capixaba (Bokermann, 1967), A. carioca (Bokermann, 1967), and A. olfersioides (A. Lutz, 1925), but in 2007 they were synonymized due to a lack of morphological differences. Although growing evidence from DNA and bioacoustics suggests that multiple species of nurse frogs inhabit the Atlantic Forest, their taxonomy has not been updated because populations at the four type localities had all vanished by the 1990s, making it impossible to collect tissues for DNA analysis and other data (e.g., vocalizations) from topotypic material. To overcome the lack of modern tissues, we employed museomics to obtain historical DNA from topotypic material of the four nominal species, which we analyzed together with data from extant populations from throughout the Atlantic Forest and Atlantic Forest enclaves within the Caatinga. We found that the Atlantic Forest nurse frogs comprise a well-supported clade of no fewer than 12 species that arrived in the Atlantic Forest via a single invasion from the Guiana Shield. We propose Dryadobates, gen. nov., for this clade, which is the sister group of all other allobatines. We consider the four nominal species to be valid, redescribe them as D. alagoanus, comb. nov., D. capixaba, comb. nov., D. carioca, comb. nov., and D. olfersioides, comb. nov., describe two sister species (D. bokermanni, sp. nov., and D. lutzi, sp. nov.) from southern Bahia, and summarize available information for the remaining six undescribed species. The type series of D. olfersioides comprises two species, so we designate a lectotype to clarify the application of the name. Dryadobates alagoanus is extant and broadly distributed, but D. capixaba, D. carioca, and D. olfersioides are presumed extinct, representing 50% of the nominal species of Dryadobates. These results provide a clear and consequential example of the essential role museomics and taxonomy play in understanding diversity loss and setting conservation priorities.
Of the many features that make frogs and toads unique, vocal sacs are among the most remarkable. Vocal sacs are inflatable, elastic chambers present in adult males of most anurans and are key elements in their social interactions. Traditionally vocal sacs have been associated primarily with acoustic communication, but their functions are currently being reinterpreted, and there is increasing evidence that they play a wider role in anuran biology. We surveyed the anatomical and histological structure of vocal sacs in all major clades of frogs by examining 777 specimens representing 605 species. Herein we characterize the morphological diversity of the three elements that compose the vocal sac: the gular skin, the superficial submandibular musculature, and the internal mucosa. We describe major anatomical patterns and define characters that we optimize on a comprehensive phylogenetic hypothesis of Anura. Integrating this anatomical information with images and videos of vocalizing frogs, we produce an updated morphological classification that includes 20 patterns of vocal sac morphology, each of which can be diagnosed by internal and external structures. Applying this classification to 4358 species, we discuss major evolutionary trends, taking ontogeny, homology, and multimodal communication into consideration. A single, spherical vocal sac is the most widely distributed vocal sac shape (present in 63% of known species), but some degree of lateralization (bilobate or paired sacs) has evolved in almost all anuran families. Some groups, such as Hylidae and Ranidae, are particularly diverse and contain more than 10 different vocal sac morphologies. Vocal sacs are absent in 18% of anurans and have been lost between 146 and 196 times, an astounding number considering their biological importance. Lastly, we review the morphological diversity and taxonomic relevance of vocal sac structures for each of the 58 families of recent anurans.
In this report, the fifth and last of our monographic series on mammalian diversity and ethnomammalogy in the Yavari-Ucayali interfluvial region of northeastern Peru, we document the local occurrence of 40 species of rodents, including 5 sciurids, 17 cricetids, 1 caviid, 1 cuniculid, 2 dasyproctids, 1 dinomyid, 2 erethizontids, and 11 echimyids. The following substantive taxonomic results, among others, are reported: (1) We discuss current issues of sciurid classification and treat all New World tree squirrels (Sciurini), except North American Tamiasciurus, as members of the genus Sciurus; the proposed subgeneric classification is monophyletic, and it conserves longstanding binomial usage for most species. (2) We describe a new species of squirrel, Sciurus ( Hadrosciurus ) pachecoi, which had previously been identified as a distinct lineage by molecular analyses. (3) We discuss the nominal taxa currently synonymized with S . (H.) pyrrhinus and comment on the application of names to phenotypes and mitochondrial haplogroups. (4) The currently accepted type locality of S . (H.) spadiceus (Cuiab & aacute;) cannot be correct; instead, documentary evidence suggests that the holotype must have been collected near Santar & eacute;m. (5) Sciurus flaviventer appears to be the only valid species of Microsciurus (sensu lato) that occurs in the Amazonian lowlands; Amazonian records of taxa previously reported in the literature as M. sabanillae and M . "species 2" appear to be based on erroneous geographic coordinates and unexplained genotype/ phenotype discordance, respectively. (6) We discuss and illustrate the diagnostic morphological characters of Nectomys apicalis and N. rattus, which have broadly overlapping distributions in northern Peru. (7) We analyze cytochrome b sequence data from 143 specimens of Oecomys from western Amazonia and summarize evidence for multiple unnamed lineages; of these, three from the Yavari-Ucayali interfluve are described as new species. (8) We question the recognition of O. tapajinus as a species distinct from O. roberti due to the lack of unambiguously diagnostic characters and the doubtful identity of the holotype of tapajinus. (9) We confirm sympatry between two species of Scolomys and provide revised diagnostic criteria for S. melanops and S. ucayalensis. (10) We report the only specimen of Dinomys branickii accompanied by definite locality data from Loreto department. (11) Proechimys quadruplicatus and P. steerei, closely related species previously thought to occur on opposite banks of the Peruvian Amazon, are both present in the Yavari-Ucayali interfluve; diagnostic characters are tabulated for the six species of Proechimys now known to occur in our region. Despite intensive and methodologically complementary faunal-sampling efforts, our rodent inventory is probably incomplete; at least four additional species could be expected to occur in our region based on geographic range data. If all four do occur there, then our inventory is about 90% complete. Documented sympatric species richness at intensively sampled sites in our region is substantially less than the regional total, but because of methodological omissions, no site is believed to have been completely inventoried for rodents. In the absence of known barriers to mammalian dispersal within the Yavari-Ucayali interfluve, however, local (sympatric) species richness is probably constrained only by habitat availability. Matses knowledge of rodents is richly detailed for primary game species ( Cuniculus paca and Dasyprocta fuliginosa) but is less detailed for less culturally important subsets of the fauna. As previously documented for other mammals (e.g., primates, xenarthrans, and ungulates), important game species are known by multiple names (including synonyms and hyponyms), whereas less culturally important but still salient species (e.g., squirrels) have single names, and many inconspicuous (e.g., small, nocturnal, and morphologically indistinguishable) species do not have unique identifiers. With the rodents treated in this report, the mammalian fauna of the Yavari-Ucayali interfluve is now known to include at least 201 species, but >20 additional species (mostly bats) could still be expected in the region based on geographic range data. Despite the probable incompleteness of our inventory, the Yavari-Ucayali interfluve is the only part of western Amazonia with an extensively documented mammal fauna. Therefore, the completion of this monographic series provides a unique taxonomic resource for urgently needed mammalogical research in this ecologically intact but increasingly vulnerable region.
The now inaccessible amber deposits of the Fushun coalfield (Guchengzi Formation; Ypresian) represent the only diverse record of Paleogene arthropods from northeastern Asia. Among the wealth of inclusions recovered from the mines before they were closed and filled, only five specimens of bees were discovered. Meager as they are, these samples provide an important paleogeographical point of reference for piecing together the fauna of forest-dwelling bees during and after the Early Eocene Climatic Optimum. Three species in two genera are recorded, one species representing a new extinct genus and tribe of Megachilinae related to Glyptapini, Ctenoplectrellini (here including Aspidosmia Brauns), and perhaps Dioxyini, and the other two species comprising a new genus of the eusocial corbiculate tribe Melikertini (Apinae). The early-diverging tribes of Megachilinae-Glyptapini, Ctenoplectrellini, and the new tribe, all possessing a distinct metatibial scopa-are briefly reviewed. Glyptosmia Engel, n. gen., with Glyptosmia hemiaspis Engel, n. sp., is the sole member of Glyptosmiini Engel, n. tribe. Although it somewhat resembles species of the genus Ctenoplectrella Cockerell (from Baltic, Bitterfeld, Oise, and Rovno ambers), Glyptosmia also shares distinctive traits of Glyptapini (areolate propodeum) and even the cleptoparasitic Dioxyini (tuberculate metanotum). The tribe can be distinguished by the bare compound eyes, dense mesosomal punctation, tuberculate metanotum, areolate propodeum, flattened mesoscutellum with a sinuate apical margin, and characteristically thickened metatibial spurs, among other characters. Two species of the corbiculate bee tribe Melikertini are described, both of the genus Thyreomelikertes Engel, n. gen. Thyreomelikertes lacks the facial protuberances found in genera such as Aethemelikertes Engel, Haidomelikertes Engel, Amelikertotes Engel, or Succinapis Engel and is superficially similar to Melissites Engel or Mochlomelikertes Engel, Breitkreuz, and Ohl, with its long, flattened, and trapezoidal mesoscutellum somewhat reminiscent of the latter genus. The genus is also noteworthy for the putatively plesiomorphic retention of relatively developed grooves on the outer surface of the mandible and dense mesosomal pubescence. The two included species, Thyreomelikertes electrosinicus, n. sp., and T . kongi, n. sp., can be distinguished by size and the development of setae on the meso- and metatibiae. All the individuals are morphologically workers, and so, like all other melikertines, Thyreomelikertes was social and, based on the phylogenetic position of the tribe, presumably lived in anchored eusocial colonies. By contrast, G . hemiaspis was likely a free-living solitary species. The species from Fushun amber are described, figured, and compared with other species of Cenozoic and living bees. The mandibular structure of Thyreomelikertes is unique among Melikertini and permits a fuller description of the diversity of structural homologies across corbiculate bee mandibles.
Parrots (Order: Psittaciformes) are a diverse clade that is easily distinguishable from other birds. Despite the clear characters that define Psittaciformes (hooked bills, zygodactylous feet, and plumage that is often predominantly green or red), relative morphological uniformity among parrots has made taxonomic classification a fraught endeavor for over a century. Parrot systematics were propelled forward when DNA sequencing data shed insights into higher- and species-level relationships. However, despite these significant advances, major gaps in taxon sampling and uncertainty in relationships remained due to inferring phylogenetic relationships with short fragments of DNA. Recent work using genome-wide molecular markers with nearly complete parrot species-level sampling has brought clarity to many of the remaining outstanding questions on taxonomic relationships. Here, we build on this work by including four additional species to present a taxonomic revision of Psittaciformes better aligned with its evolutionary tree. We infer maximum likelihood and time-calibrated phylogenies for parrots, present accounts for 106 genera, compare how our findings relate to previous work, and highlight future areas of research. The family-group nomenclature we propose reflects deep evolutionary divergences with diagnosable synapomorphies that are commensurate across comparable ranks in psittaciform clades. We erect three new family-group names at the rank of tribe (Brotogerini Smith, Thom, and Joseph, 2024; Neophemini Schodde, Mason, Smith, Thom, and Joseph, 2024; Bolbopsittacini Smith, Thom, and Joseph, 2024). We elevate one tribe to subfamily rank for the cacatuid genus Probosciger and we restrict usage of the recently introduced tribe Touitini to its type genus Touit. At shallower taxonomic scales, recognition of more rather than fewer genera addresses issues of paraphyly or high discordance in morphological and genomic characters at those levels. We support many reinstatements of older generic names advocated in recent decades, and we further reinstate five valid, available generic names not widely used in recent literature if at all (Licmetis, Gymnopsittacus, Clarkona, Suavipsitta, Cardeos). We advocate the retention of Vini Lesson, 1833, over Coriphilus Wagler, 1832, based on preliminary examination showing substantially more frequent usage of the former. We redraw generic limits in some other cases (e.g., Bolborhynchus parrotlets and allies) and this includes recognizing fewer genera than recently proposed for the Psittacula sensu lato ringneck parakeets. Our revised classification of parrots addresses many longstanding taxonomic questions including those that have arisen through the acquisition of genetic data. It provides context for the temporal origins of psittaciform clades and the taxonomic and phenotypic diversification throughout their evolutionary history. We hope that it will be a benchmark guiding further taxonomic study as well as for downstream analyses in many other fields.
The genus Trachylepis is currently represented by 21 species in Angola, most of them part of nomenclaturally and taxonomically challenging species complexes. In this study we present an integrative taxonomic revision of the genus in Angola and describe seven new species: Trachylepis attenboroughi, sp. nov., Trachylepis bouri, sp. nov., Trachylepis hilariae, sp. nov., Trachylepis ovahelelo, sp. nov., Trachylepis suzanae, sp. nov., Trachylepis vunongue, sp. nov., and Trachylepis wilsoni, sp. nov. As result of our taxonomic revisions, 25 valid Trachylepis species are now confirmed from Angola. A phylogenetic analysis using a combination of mitochondrial (16S, ND2) and nuclear (RAG1) markers, as well as morphological data, supports the recognition of the new species. In addition, data support the revalidation of Trachylepis albopunctata (Bocage, 1867), Trachylepis notabilis (Peters, 1879), and Trachylepis ansorgii (Boulenger, 1907). We also provide a redefinition of Euprepes anchietae Bocage, 1866, which we synonymize with Trachylepis maculilabris (Gray, 1845). Given that the type material for Trachylepis albopunctata, T. angolensis, and T. anchietae has been lost or destroyed, we designate neotypes for the purpose of nomenclatural stability. The description of the new species and the revision and revalidation of previously described Angolan species contribute to a better understanding of the taxonomy and biogeography of the genus, as well as to the general biogeographic patterns and evolution of the Angolan fauna.
Known from over 50 Triassic localities worldwide, beetles were a significant component of the early Mesozoic paleofauna. Beetle fossils are particularly diverse in the Late Triassic (Norian) Cow Branch and Walnut Cove formations (Solite deposit) of Virginia and North Carolina, with 100 distinct morphotypes sorted from approximately 1000 specimens. The diversity of the Solite Coleoptera is documented, the 100 beetle morphotypes are informally described, and comparisons are made with other beetle communities through geologic time. In comparison with modern beetle communities, the Solite fauna shares two remarkable similarities. First, the distribution of Solite beetle body sizes matches that of some modern beetle communities, with the majority of specimens in both groups measuring between 2 and 4 mm in length. Second, the vast majority of the 100 Solite morphotypes (84%) are known from only a single specimen. This pattern somewhat follows the species abundance distribution of modern animal communities, in which a community is comprised of only a few common species and many rare species. In contrast, the Solite beetle fauna differs markedly from those of other Triassic and Early Jurassic deposits, both in the composition of higher taxa present, as well as in the lack of shared taxa between sites. The uniqueness of the Solite taxa, including the remarkable diversity, demonstrate the importance of the Solite Konservat-Lagerstatte in understanding the evolutionary history of Order Coleoptera.
The genus Trachylepis is currently represented by 21 species in Angola, most of them part of nomenclaturally and taxonomically challenging species complexes. In this study we present an integrative taxonomic revision of the genus in Angola and describe seven new species: Trachylepis attenboroughi, sp. nov., Trachylepis bouri, sp. nov., Trachylepis hilariae, sp. nov., Trachylepis ovahelelo, sp. nov., Trachylepis suzanae, sp. nov., Trachylepis vunongue, sp. nov., and Trachylepis wilsoni, sp. nov. As result of our taxonomic revisions, 25 valid Trachylepis species are now confirmed from Angola. A phylogenetic analysis using a combination of mitochondrial ( 16S, ND2) and nuclear (RAG1) markers, as well as morphological data, supports the recognition of the new species. In addition, data support the revalidation of Trachylepis albopunctata (Bocage, 1867), Trachylepis notabilis (Peters, 1879), and Trachylepis ansorgii (Boulenger, 1907). We also provide a redefinition of Euprepes anchietae Bocage, 1866, which we synonymize with Trachylepis maculilabris (Gray, 1845). Given that the type material for Trachylepis albopunctata, T. angolensis, and T. anchietae has been lost or destroyed, we designate neotypes for the purpose of nomenclatural stability. The description of the new species and the revision and revalidation of previously described Angolan species contribute to a better understanding of the taxonomy and biogeography of the genus, as well as to the general biogeographic patterns and evolution of the Angolan fauna.
ABSTRACT Thomasomys cinereus is the type species of Thomasomys, type genus of the sigmodontine tribe Thomasomyini. As currently recognized, Thomasomys includes 48 species, all of which are endemic to humid montane or premontane forests in the tropical Andes. Although it has been suggested that T. cinereus is a species complex, this hypothesis has yet to be critically evaluated. Herein we provide a revision of the species based on a qualitative assessment of external, craniodental, and soft morphological traits; morphometric analyses; a phylogenetic analysis based on cytochrome b gene sequences; species delimitation methods; and first-hand examination of type material. Our analyses of genetic data recovered four distinct clades within T. cinereus, one corresponding to T. cinereus sensu stricto (restricted to the montane forests delimited by the Río Marañón, Río Huancabamba, and Río Tablachaca in Cajamarca department, Peru) and three new species: Thomasomys lojapiuranus, sp. nov., from the montane forests of Piura department, Peru, and Loja province, Ecuador; T. shallqukucha, sp. nov., restricted to the Kañaris montane forests in the Peruvian department of Lambayeque; and T. pagaibambensis, sp. nov., restricted to the montane forests of Pagaibamba in Cajamarca department, Peru. These species can be distinguished by several discrete morphological traits of the skull, dentition, mandible, stomach, palatal rugae, and glans penis. Genetic distances among these taxa range from 5.06%–7.65% at the cytochrome b locus, and delimitation analyses based on cytochrome b sequence data support their recognition as distinct species. Our results suggest the existence of previously unsuspected dispersal barriers in the Andes of northern Peru, and they confirm that the Río Marañón is a formidable barrier that limits the distribution of species of Thomasomys as well as other sigmodontine rodents.
Mosasaurs are large, carnivorous aquatic lizards with a global distribution that lived during the Late Cretaceous. After 200 years of scientific study, new mosasaur species are still being discovered as new localities are explored and specimens collected long ago are reevaluated using modern standards of species delimitation. Even so, the phylogenetic positions of many key taxa are unresolved and therefore our understanding of mosasaur macroevolution is muddled. Here, we describe a new genus and species of mosasaurine mosasaur comprising a partial skull and skeleton from the Pembina Member of the Pierre Shale Formation in Cavalier County, North Dakota. The lower bound on the age of the specimen is 80.04 +/- 0.11 Ma, provided by the underlying bentonite bed. Its skull and jaws are nearly complete, and the postcranial skeleton preserves seven cervical vertebrae with three hypapophyseal peduncles, 11 ribs, and five anterior dorsal vertebrae. The new specimen was scored into a modified version of an existing phylogenetic matrix of Mosasauroidea and was recovered in a polytomy with Clidastes; however, given that its morphology is significantly different from that of Clidastes, we refer it to a new genus and species, Jormungandr walhallaensis. Notably, this new taxon shares a mosaic of features seen in both basal (e.g., Clidastes; high dental counts) and derived (e.g., Mosasaurus; subrectangular quadrate) mosasaurines, in addition to possessing its own unique suite of autapomorphies. Given that it possesses morphology intermediate between Clidastes and Plotosaurini, we suspect that future analyses of mosasaur phylogeny, following the addition of new characters and taxa, will recover Jormungandr as transitional between them. Its occurrence increases the known diversity of mosasaurs from the Pembina Member and is the earliest mosasaur to possess autapomorphies of Plotosaurini. Finally, we also analyzed the matrix using different outgroups to test their effect on tree topology and resolution, and found that including multiple nonmosasauroid anguimorphs increased resolution, but not support, of mosasaurid ingroup relationships.
