165 research outputs found
Cranial osteology of Hypoptophis (Aparallactinae : Atractaspididae: Caenophidia), with a discussion on the evolution of its fossorial adaptations
Fossoriality evolved early in snakes, and has left its signature on the cranial morphology of many extinct Mesozoic and early Caenozoic forms. Knowledge of the cranial osteology of extant snakes is indispensable for associating the crania of extinct lineages with a particular mode of life; this applies to fossorial taxa as well. In the present work, we provide a detailed description of the cranium of Hypoptophis wilsonii, a member of the subfamily Aparallactinae, using micro-computed tomography (CT). This is also the first thorough micro-CT-based description of any snake assigned to this African subfamily of predominantly mildly venomous, fossorial, and elusive snakes. The cranium of Hypoptophis is adapted for a fossorial lifestyle, with increased consolidation of skull bones. Aparallactines show a tendency toward reduction of maxillary length by bringing the rear fangs forward. This development attains its pinnacle in the sister subfamily Atractaspidinae, in which the rear fang has become the "front fang" by a loss of the part of the maxilla lying ahead of the fang. These dentitional changes likely reflect adaptation to subdue prey in snug burrows. An endocast of the inner ear of Hypoptophis shows that this genus has the inner ear typical of fossorial snakes, with a large, globular sacculus. A phylogenetic analysis based on morphology recovers Hypoptophis as a sister taxon to Aparallactus. We also discuss the implications of our observations on the burrowing origin hypothesis of snakes.Peer reviewe
Miscellanea Herpetologica Gabonica V & VI
We report the first observations of the orange morph and new locality records for Atherissquamigera (Viperidae) in Gabon, and new Gabonese locality records, ecological data orunpublished museum material for Pelusios castaneus and P. chapini (Pelomedusidae),Kinixys erosa (Testudinidae), Trionyx triunguis (Trionychidae), Crocodylus niloticus,Mecistops cataphractus and Osteolaemus tetraspis (Crocodylidae), Agama agama and A.lebretoni (Agamidae), Chamaeleo dilepis, C. oweni and Rhampholeon spectrum(Chamaeleonidae), Hemidactylus echinus and H. mabouia (Gekkonidae), Gerrhosaurusnigrolineatus (Gerrhosauridae), Trachylepis maculilabris and T. p. polytropis (Scincidae),Varanus ornatus (Varanidae), Crotaphopeltis hotamboeia, Dipsadoboa underwoodi,Hapsidophrys smaragdinus, Philothamnus carinatus and P. heterodermus, Rhamnophisaethiopissa, Thrasops flavigularis (Colubridae), Pseudohaje goldii (Elapidae), Aparallactusmodestus, Atractaspis boulengeri, Buhoma depressiceps, Hormonotus modestus,Psammophis cf. phillipsii (Lamprophiidae), Python sebae (Pythonidae), Indotyphlopsbraminus (Typhlopidae), Bitis nasicornis and Causus lichtensteinii (Viperidae). We add onespecies each to Estuaire, Haut-Ogooué and Ogooué-Ivindo provinces’ reptile lists. Twosnake species are added to Ivindo National Park, bringing the total number of reptile speciesrecorded from the park to 64, i.e., half of the species currently recorded from Gabon. Wedocument predation cases of Pycnonotus barbatus (Aves: Pycnonotidae) on Hemidactylusmabouia, Philothamnus heterodermus on Arthroleptis variabilis (Amphibia: Arthroleptidae),Hormonotus modestus on Hemidactylus mabouia, Psammophis cf. phillipsii onGerrhosaurus nigrolineatus, Causus lichtensteinii on Sclerophrys sp. (Amphibia:Bufonidae) and feeding of Varanus ornatus on spaghetti
Ultraconserved elements-based phylogenomic systematics of the snake superfamily Elapoidea, with the description of a new Afro-Asian family
The highly diverse snake superfamily Elapoidea is considered to be a classic example of ancient, rapid radiation. Such radiations are challenging to fully resolve phylogenetically, with the highly diverse Elapoidea a case in point. Previous attempts at inferring a phylogeny of elapoids produced highly incongruent estimates of their evolutionary relationships, often with very low statistical support. We sought to resolve this situation by sequencing over 4,500 ultraconserved element loci from multiple representatives of every elapoid family/sub-family level taxon and inferring their phylogenetic relationships with multiple methods. Concatenation and multispecies coalescent based species trees yielded largely congruent and well-supported topologies. Hypotheses of a hard polytomy were not retained for any deep branches. Our phylogenies recovered Cyclocoridae and Elapidae as diverging early within Elapoidea. The Afro-Malagasy radiation of elapoid snakes, classified as multiple subfamilies of an inclusive Lamprophiidae by some earlier authors, was found to be monophyletic in all analyses. The genus Micrelaps was consistently recovered as sister to Lamprophiidae. We establish a new family, Micrelapidae fam. nov., for Micrelaps and assign Brachyophis to this family based on cranial osteological syn-apomorphy. We estimate that Elapoidea originated in the early Eocene and rapidly diversified into all the major lineages during this epoch. Ecological opportunities presented by the post-Cretaceous-Paleogene mass extinction event may have promoted the explosive radiation of elapoid snakes.Peer reviewe
New range limits of the sun-tailed monkey, Cercopithecus solatus, in Central Gabon
Cercopithecus solatus is a recently discovered monkey endemic to Gabon, present in parts of the Lopé National Park and the Forêt des Abeilles in the center of the country. It is listed as Vulnerable on the IUCN Red List (2010) due to its restricted extent of occurrence and continuing decline in population caused by high hunting pressure. All known field observations of this species are compiled here. Data collected since 1999 show that C. solatus occurs further to the south, east, and west than was previously known, and that its extent of occurrence almost certainly includes three national parks, rather than one
Molecular and pathological signatures of epithelial–mesenchymal transitions at the cancer invasion front
Reduction of epithelial cell–cell adhesion via the transcriptional repression of cadherins in combination with the acquisition of mesenchymal properties are key determinants of epithelial–mesenchymal transition (EMT). EMT is associated with early stages of carcinogenesis, cancer invasion and recurrence. Furthermore, the tumor stroma dictates EMT through intensive bidirectional communication. The pathological analysis of EMT signatures is critically, especially to determine the presence of cancer cells at the resection margins of a tumor. When diffusion barriers disappear, EMT markers may be detected in sera from cancer patients. The detection of EMT signatures is not only important for diagnosis but can also be exploited to enhance classical chemotherapy treatments. In conclusion, further detailed understanding of the contextual cues and molecular mediators that control EMT will be required in order to develop diagnostic tools and small molecule inhibitors with potential clinical implications
Measurement of nuclear modification factors of gamma(1S)), gamma(2S), and gamma(3S) mesons in PbPb collisions at root s(NN)=5.02 TeV
The cross sections for ϒ(1S), ϒ(2S), and ϒ(3S) production in lead-lead (PbPb) and proton-proton (pp) collisions at √sNN = 5.02 TeV have been measured using the CMS detector at the LHC. The nuclear modification factors, RAA, derived from the PbPb-to-pp ratio of yields for each state, are studied as functions of meson rapidity and transverse momentum, as well as PbPb collision centrality. The yields of all three states are found to be significantly suppressed, and compatible with a sequential ordering of the suppression, RAA(ϒ(1S)) > RAA(ϒ(2S)) > RAA(ϒ(3S)). The suppression of ϒ(1S) is larger than that seen at √sNN = 2.76 TeV, although the two are compatible within uncertainties. The upper limit on the RAA of ϒ(3S) integrated over pT, rapidity and centrality is 0.096 at 95% confidence level, which is the strongest suppression observed for a quarkonium state in heavy ion collisions to date. © 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.Peer reviewe
AVONET: morphological, ecological and geographical data for all birds
Functional traits offer a rich quantitative framework for developing and testing theories in evolutionary biology, ecology and ecosystem science. However, the potential of functional traits to drive theoretical advances and refine models of global change can only be fully realised when species‐level information is complete. Here we present the AVONET dataset containing comprehensive functional trait data for all birds, including six ecological variables, 11 continuous morphological traits, and information on range size and location. Raw morphological measurements are presented from 90,020 individuals of 11,009 extant bird species sampled from 181 countries. These data are also summarised as species averages in three taxonomic formats, allowing integration with a global phylogeny, geographical range maps, IUCN Red List data and the eBird citizen science database. The AVONET dataset provides the most detailed picture of continuous trait variation for any major radiation of organisms, offering a global template for testing hypotheses and exploring the evolutionary origins, structure and functioning of biodiversity
FIG. 2. — A, C, E in Révision du genre Peltidopeplus Poppius, 1912, avec description d'une espèce nouvelle de Papouasie et d'un genre nouveau d'Australie (Insecta, Heteroptera, Miridae, Mirini)
FIG. 2. — A, C, E, Peltidopeplus annulipes Poppius, 1912; B, D, F, P. yasunagai n. sp.; A, B, ACH (processus basal + processus sclérifié sensu Stonedahl, 1988); C, D, partie médiane du vagin en vue dorsale; E, F, paroi postérieure en vue dorsale. Échelles: 0,1mm.Published as part of Chérot, Frédéric & Pauwels, Olivier S. G., 2000, Révision du genre Peltidopeplus Poppius, 1912, avec description d'une espèce nouvelle de Papouasie et d'un genre nouveau d'Australie (Insecta, Heteroptera, Miridae, Mirini), pp. 121-137 in Zoosystema 22 (1) on page 127, DOI: 10.5281/zenodo.539530
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