6814 research outputs found
Sort by
A new dromaeosaurid from the Late Cretaceous Khulsan locality of Mongolia (American Museum novitates, no. 3965)
46 pages : color illustrations, map ; 26 cm.A new dromaeosaurid dinosaur, Shri devi, from the Late Cretaceous deposit of the Barun Goyot Formation at Khulsan, Mongolia, is described here. The Barun Goyot Formation (herein referred to as the Barun Goyot) is stratigraphically intermediate between the overlying Nemegt Formation and the underlying Djadokhta Formation, where much of the dromaeosaurid diversity has been reported to date. Sediments of the Barun Goyot are typically considered Upper Campanian in age. Although dromaeosaurid remains have been noted to occur in the Barun Goyot for decades, descriptive and taxonomic work has never been completed for the material. The holotype specimen (IGM 100/980) consists of a partially articulated individual preserving the right hind limb; left tibiotarsus; pelvis; and adjacent cervical, dorsal, and caudal vertebrae. IGM 100/980 is referable to a clade with Velociraptor based on the presence of a distinct ambiens tubercle located proximally on the anterior face of the pubis, a well-developed anterior tuberosity proximally located on the ischium, and a rounded longitudinal ischial ridge. It is distinguishable from V. mongoliensis based on a weak fourth trochanter (shared with all other dromaeosaurids) and deep anterior pedicular fossae in the cervical vertebrae; epipophyses in the last four cervicals are not raised but are instead represented by rugose circular scars. A suite of axial and appendicular characters are diagnostic for the new species. New discoveries including Shri devi allow for an improved understanding of dromaeosaurid anatomy, as well as the temporal and regional variation of the dromaeosaurid fauna of Mongolia and Inner Mongolia (Nei Mongol Autonomous Region, China), during the Late Cretaceous
Biofluorescence in Arctic snailfishes
12 pages : illustrations (chiefly color) ; 26 cm.Biofluorescence has recently been reported to be phylogenetically widespread and phenotypically variable across bony fishes, and is most common in tropical coral reef lineages. Here we provide the first documentation of prominent biofluorescence in Arctic fishes including two juvenile specimens of Liparis gibbus (variegated snailfish) collected from the coastal waters of Eastern Greenland, as well as an adult L. tunicatus (kelp snailfish) collected in the Bering Strait off of Little Diomede Island, AK. Observations of L. gibbus were made during nighttime dives within kelp forests in iceberg habitats in Southeastern Greenland in August 2019. The juvenile L. gibbus specimens exhibit both green (523-530 nm) and red (674-678 nm) biofluorescence on discrete anatomical areas, which provides a rare example of multiple fluorescent colors emitted from a single individual. Notably, the adult L. tunicatus emitted only red fluorescence in a bilaterally symmetrical pattern of discrete red dots and blotches. Potential weak green biofluorescence was also noted in a flatfish (Hippoglossoides platessoides) collected in Greenland, but in no other Arctic species. As the distribution and function of biofluorescence in marine fishes is further examined, this report adds context to its widespread geographical and environmental distributions, and shows that, although rare, biofluorescence does occur in Arctic fish lineages
Total evidence phylogenetic analysis supports new morphological synapomorphies for Bovidae (Mammalia, Artiodactyla) (American Museum novitates, no. 3970)
38 pages : illustrations ; 26 cm.Advances in gene sequencing technology have made it easier to generate large molecular datasets with novel DNA sequences for phylogenetic analysis. Because morphological data are difficult to collect and not required for molecular phylogenetic analyses, they are often excluded in studies of the systematic relationships of extant taxa. This fact is especially apparent in the Bovidae, the highly diverse, widespread clade of hoofed mammals most often characterized by the presence of permanent bony horn cores covered with keratin sheaths. Analyses of molecular data have reconstructed well-supported phylogenetic relationships within the clade. However, morphological data are also required to integrate fossil taxa into these studies, and may support different topologies when they are included in total evidence phylogenies. In this study, I performed a maximum likelihood phylogenetic analysis of a total evidence dataset including mitochondrial genomes, nine nuclear genes, and 196 morphological characters. The dataset comprises 156 species, 13 of which are fossil taxa, one of the most complete analyses of the family to date, and the first time many of the fossil species have been included in a total evidence analysis. Character optimizations on this topology produced seven synapomorphic morphological characters for Bovidae and multiple characters for each tribe. These analyses support the use of total evidence phylogenetics as a means of uncovering morphological characters that may serve as new synapomorphies and elucidate the systematic relationships of fossil species
Systematics of West African "giant" Ricinulei
68 pages : illustrations (2 color) ; 26 cm.The Ricinulei Thorell, 1876, or "hooded tick-spiders," are among the rarest and least studied arachnid orders. Ricinoides Ewing, 1929, the only Old World genus of extant ricinuleids, with 11 species described from tropical West Africa, is the most neglected of the three genera currently recognized. A lack of attention to the systematics of Ricinoides has created a disparity between its taxonomic diversity and that of the New World genera, Cryptocellus Westwood, 1874, and Pseudocellus Platnick, 1980, in which many new species have been described in recent decades. The present contribution provides a revised diagnosis of Ricinoides, which includes two new, putative synapomorphies for the genus and addresses the systematics and morphology of a group of West African species, which includes the world's largest ricinuleids and the type species of the genus. This group of nine species, referred to as the "giant" Ricinulei, shares a unique combination of characters, many of which appear to be unique to the group, and appears to be monophyletic. Four species of this group are redescribed, with revised diagnoses, based on reexamination of the type material: Ricinoi des afzelii (Thorell, 1892), from Sierra Leone; Ricinoides atewa Naskrecki, 2008, from Ghana; Ric inoides feae (Hansen, 1921), from Guinea-Bissau; and Ricinoides westermannii (Guérin-Méneville, 1838), from Togo. Five new species are described, raising the number of species in the genus to 16: Ricinoides eburneus, sp. nov., and Ricinoides taii, sp. nov., from Côte d'Ivoire; Ricinoides iita, sp. nov., from Nigeria; Ricinoides kakum, sp. nov., from Ghana; and Ricinoides nzerekorensis, sp. nov., from Guinea. Comparative illustrations of the adult morphology are presented for all nine species. The male copulatory apparatus is described and illustrated in detail, and new terminology and characters presented. The female spermathecae are described and illustrated for six species in which the females are known, representing the first illustrated comparison of these structures in African ricinuleids. Geographical distribution records are revised and updated for the different species, and their distributions mapped
Fourteen new, endemic species of shrew (genus Crocidura) from Sulawesi reveal a spectacular island radiation (Bulletin of the American Museum of Natural History, no. 454)
108 pages : illustrations (some color), maps ; 26 cm.After nearly a decade of field inventories in which we preserved voucher specimens of the small terrestrial mammals of Sulawesi, we combined qualitative and quantitative analyses of morphological traits with molecular phylogenetics to better understand the diversity of shrews (Soricidae: Crocidura) on the island. We examined the morphology of 1368 specimens and obtained extensive molecular data from many of them, including mitochondrial DNA sequences from 851 specimens, up to five nuclear exons from 657 specimens, and thousands of ultraconserved elements from 90 specimens. By iteratively testing species limits using distinct character datasets and appropriate taxon sampling, we found clear, mostly consistent evidence for the existence of 21 species of shrews on Sulawesi, only seven of which were previously recognized. We divide these 21 species into five morphogroups, provide emended diagnoses of the seven previously named species, and describe 14 new species. The Long-Tailed Group contains Crocidura caudipilosa, C. elongata, C. microelongata, new species, and C. quasielongata, new species; the Rhoditis Group contains C. rhoditis, C. pseudorhoditis, new species, C. australis, new species, and C. pallida, new species; the Small-Bodied Group contains C. lea, C. levicula, C. baletei, new species, C. mediocris, new species, C. parva, new species, and C. tenebrosa, new species; the Thick-Tailed Group contains C. brevicauda, new species and C. caudicrassa, new species; and the Ordinary Group contains C. musseri, C. nigripes, C. normalis, new species, C. ordinaria, new species, and C. solita, new species. Documenting these endemic species reveals a local radiation (20 of the 21 species are members of an endemic clade) in which elevational gradients played a prominent role in either promoting speciation, or at a minimum, fostering the cooccurrence of phenotypically similar species. As now understood, the species-level diversity of Crocidura on Sulawesi is nearly three times the known diversity of any other insular shrew fauna. This study highlights the fact that if we wish to understand the true extent of biodiversity on Earth, large-scale, vouchered organismal inventories followed up with thorough examinations of genetic, morphological, and geographic traits are sorely needed in montane tropical regions, even for purportedly well-studied groups such as mammals
Systematic revision of the sand scorpions, genus Buthacus Birula, 1908 (Buthidae C.L. Koch, 1837) of the Levant, with redescription of Buthacus arenicola (Simon, 1885) from Algeria and Tunisia (Bulletin of the American Museum of Natural History, no. 450)
134 pages : illustrations (some color), maps ; 26 cmScorpions of the genus Buthacus Birula, 1908 (Buthidae C.L. Koch, 1837), commonly known as "sand scorpions," are widespread in the sandy deserts of the Palearctic, from West Africa to India. Although many new species of Buthacus were described in recent years, no modern revision exists for the genus and the limits of many infrageneric taxa remain unclear. The present contribution addresses the species of Buthacus recorded from the Levant, defined here as the region of the Middle East including Syria, Lebanon, Jordan, Israel, the Palestinian territories, and the Sinai Peninsula (Egypt). Prior to this study, five species and subspecies, including several synonyms, were recognized from the region. Based on extensive new collections, a reassessment of the morphology (including multivariate statistical analysis), and a phylogenetic analysis of morphological and DNA sequence data, published elsewhere, seven species of Buthacus are now recognized from the Levant, raising the number of species in the genus to 30. Three new species are described: Buthacus amitaii, sp. nov., endemic to Israel; Buthacus arava, sp. nov., endemic to Israel and Jordan; and Buthacus levyi, sp. nov., endemic to Egypt, Israel, and perhaps Libya. Buthacus arenicola (Simon, 1885) is redescribed and restricted to northeastern Algeria and central Tunisia, and Buthacus leptochelys (Ehrenberg, 1829) redescribed and restricted to Egypt, Sudan, and perhaps Libya. Buthacus armasi Lourenço, 2013, stat. rev., from southern Algeria, and Buthacus spatzi (Birula, 1911), stat. rev., from southern Tunisia and western Libya, are revalidated, and Buthacus fuscata Pallary, 1929, stat. nov. et stat. rev., from southern Algeria, revalidated and elevated to the rank of species. Buthacus nitzani Levy et al., 1973, stat. nov., currently restricted to Israel but probably present in the Sinai Peninsula (Egypt), is elevated to the rank of species. Buthacus tadmorensis (Simon, 1892), stat. rev., recorded from Iran, Iraq, Jordan, Syria, and Turkey, and Buthacus yotvatensis Levy et al., 1973, stat. rev., endemic to Israel and Jordan, are redescribed and revalidated. Three new synonyms are presented: Androctonus (Leiurus) macrocentrus Ehrenberg, 1828 = Buthacus leptochelys (Ehrenberg, 1829), syn. nov.; Buthus pietschmanni Penther, 1912 = Buthacus tadmorensis (Simon, 1892), syn. nov.; Buthacus granosus Borelli, 1929 = Buthacus leptochelys (Ehrenberg, 1829), syn. nov. Buthacus arenicola and the seven species of Buthacus occurring in the Levant are diagnosed and illustrated to modern standards, with updated distribution maps. A list of the currently recognized species of Buthacus, and a key to identification of the species occurring in the Levant are also presented
Total-evidence phylogeny of the New World Polistes Lepeletier, 1836, paper wasps (Vespidae, Polistinae, Polistini) (American Museum novitates, no. 3973)
42 pages : illustrations (chiefly color) ; 26 cm.The genus Polistes is one of the most species-rich and widely distributed groups of social wasps and a model taxon for studies of social behavior. Almost half the Polistes world fauna occurs in the New World, but their classification has been unstable due in part to the scarcity of phylogenetic studies. We investigated the phylogeny of the New World Polistes by combining a previously existing molecular dataset with a new morphological and behavioral matrix for 90 of the 93 New World species. All analyses support a single origin for the New World Polistes. All five traditionally defined New World subgenera (Aphanilopterus, Epicnemius, Fuscopolistes, Onerarius, and Palisotius) were monophyletic, but the relationships among them varied across datasets. Our results, with an expanded phenotypic dataset, improved taxonomic sampling, and enhanced clade support relative to previous studies, strongly support a classification based on five subgenera, which are all diagnosable groups supported by clear morphological synapomorphies. Hence, we propose the revalidation of previously proposed subgenera; we provide a taxonomic account of each subgenus and an identification key to all species of New World Polistes
Two new Phenacogrammus (Characoidei; Alestidae) from the Ndzaa River (Mfimi-Lukenie basin) of central Africa, Democratic Republic of Congo (American Museum novitates, no. 3980)
22 pages : color illustrations, color map ; 26 cm.Two new Phenacogrammus are described from the Ndzaa River, a small left-bank tributary of the Mfimi-Lukenie River in the central Congo basin. They share with P. deheyni, a congener endemic to the Cuvette Centrale to the north, a prominent anterior expansion of the first pleural rib; a feature interpreted here as a synapomorphy diagnostic for this species assemblage. The two new species are readily differentiated from P. deheyni based on differences in pigmentation patterning, a lower number of scales in longitudinal series (26–28 vs. 29–33) and a longer head length (m. 24.9% SL vs. 21.7 and 23.2% SL). Phenacogrammus flexus, new species, is distinguished from all congeners in the possession of 6 (vs. 7) supraneural bones, and a characteristic zigzag pattern of black pigmentation along and below the midline extending from the posterior border of the opercle to the base of the caudal peduncle. While no unambiguous morphological autapomorphies have been located to diagnose P. concolor, new species, it is nonetheless readily distinguished from all congeners, except P. deheyni and P. flexus, in the possession of a prominent anterior expansion of the first pleural rib. It differs from both P. deheyni and P. flexus in the absence of a dominant pigmentation patterning over the flanks and caudal peduncle. Additionally, it differs from P. flexus in a shallower body depth (m. 24.9% vs. 27.0% SL) and in the possession of 7 (vs. 6) supraneurals. The three species exhibit extensive divergence in mt-COI sequence (P. flexus vs. P. concolor 10.2%–11%; P. flexus vs deheyni 12.9%–13.5%; P. concolor vs. deheyni 11.3%–12.9%). Furthermore, analysis of shape variation utilizing geometric morphometrics indicates that each species differs significantly in body shape
The bacterial diversity lurking in protist cell cultures (American Museum novitates, no. 3975)
14 pages : illustrations (some color) ; 26 cm.Laboratory cultures of heterotrophic protists are often xenic, meaning that the culture contains more than one microbial organism. In this study, we analyzed genome-assembly data from cultures of four marine protist flagellates—the marine malawimonad Imasa heleensis, the undescribed mantamonad strain SRT-306, the discobid Ophirina amphinema, and the cryptist Palpitomonas bilix—specifically to search for genomes of cocultured bacteria. As no external bacteria have been added to the protist stock cultures, it is probable that the cocultured bacteria came from the original water samples from which the protists were isolated. At least some of these bacteria are consumed as a food source by the protists, all of which are obligate heterotrophs. From four separate metagenomic de novo assemblies for these mixed cultures, we identified 28 scaffolds, which BUSCO analyses suggest represent complete or near-complete bacterial genomes. These scaffolds range in length from 3,139,436 to 6,090,282 bp and encode 2873 to 5666 genes. Only eight of the 28 scaffolds corresponded to entries in the NCBI genome database, meaning that 20 of these scaffolds represent genomes from putatively novel bacterial species. Our findings highlight that data like these, which are often discarded or overlooked, can be a source of novel genomes and/or species
Four new species of “hooded tick-spiders” (Ricinulei, Ricinoididae) from South and Central America : with clarification of the identity of Cryptocellus leleupi Cooreman, 1976 (American Museum novitates, no. 3976)
35 pages : illustrations (some color), map ; 26 cm.The Ricinulei Thorell, 1876, or “hooded tick-spiders,” are among the least studied arachnid orders. Knowledge of ricinuleid diversity has been slow to accumulate because these arachnids are underrepresented in biological collections. Despite an increase in the pace of new species descriptions in recent decades, the species richness of the order probably remains vastly underestimated. Large areas in some of the world’s most biodiverse countries are without a single record for the order, hence new records invariably turn out to be new species. The present contribution describes four new species of the mostly South American genus Cryptocellus Westwood, 1874: Cryptocellus canutama, sp. nov., and Cryptocellus jamari, sp. nov., from Brazil; Cryptocellus islacolon, sp. nov., from Panama; and Cryptocellus macagual, sp. nov., from Colombia. Additionally, a new diagnosis and description are provided for Cryptocellus leleupi Cooreman, 1976, long considered a nomen dubium. The known locality records of the five species and their putative relatives are mapped. The present contribution raises the number of Cryptocellus species to 45 and the number of extant species of Ricinulei to 101