Two new species of the uropeltid snake genus Rhinophis Hemprich, 1820 are described from Sri Lanka. Rhinophis martin sp. nov.
View Article and Find Full Text PDFA new species of the uropeltid ('shieldtail') snake genus Uropeltis is described based on eight specimens from the southern part of peninsular India's Western Ghats. Uropeltis caudomaculata sp. nov.
View Article and Find Full Text PDFUnusually for oceanic islands, the granitic Seychelles host multiple lineages of endemic amphibians. This includes an ancient (likely ca. 60 million years) radiation of eight caecilian species, most of which occur on multiple islands.
View Article and Find Full Text PDFNonvisual opsins are transmembrane proteins expressed in the eyes and other tissues of many animals. When paired with a light-sensitive chromophore, nonvisual opsins form photopigments involved in various nonvisual, light-detection functions including circadian rhythm regulation, light-seeking behaviors, and seasonal responses. Here, we investigate the molecular evolution of nonvisual opsin genes in anuran amphibians (frogs and toads).
View Article and Find Full Text PDFThe degree to which burrowing, soil-dwelling caecilian amphibians spend time on the surface is little studied, and circadian rhythm has not been investigated in multiple species of this order or by manipulating light-dark cycles. We studied surface-activity rhythm of the Indian caecilians Ichthyophis cf. longicephalus and Uraeotyphlus cf.
View Article and Find Full Text PDFThe ultrastructure of snake sperm has received substantial attention primarily because snakes exhibit considerable variability in reproductive characteristics between species, with a wide range of mating systems and reproductive behaviors. Variability of sperm morphology among snake species may be associated with the reproductive strategies of each taxon, such as competition or sperm storage. We provide a detailed description of the sperm ultrastructure of nine snake species (Anilius scytale, Tropidophis paucisquamis, Bothrops jararaca, Oxyrhopus guibei, Dipsas mikanii, Micrurus corallinus, Xenopholis scalaris, Acrochordus javanicus, and Cylindrophis ruffus) and compared this with sperm data from the literature for the following taxa: Liotyphlops beui, Amerotyphlops reticulatus, Trilepida koppesi, Anilios waitii, Anilios endoterus, Aspidites melanochephalus, Boa constrictor amarali, Corallus hortulana, Epicrates cenchria, Boa constrictor occidentalis, Eryx jayakari, Micrurus corallinus, Micrurus surinamensis, Micrurus frontalis, Micrurus altirostris, Oxyuranus microlepidotus, Bothrops alternatus, Bothrops diporus, Crotalus durissus, Agkistrodon contortrix, Vipera aspis, Boiga irregularis, Zamenis schrenckii, Zamenis scalaris, Stegonotus cuculatus, Nerodia sipedon, Liodytes pygaea, and Myrrophis chinensis.
View Article and Find Full Text PDFVisual systems adapt to different light environments through several avenues including optical changes to the eye and neurological changes in how light signals are processed and interpreted. Spectral sensitivity can evolve via changes to visual pigments housed in the retinal photoreceptors through gene duplication and loss, differential and coexpression, and sequence evolution. Frogs provide an excellent, yet understudied, system for visual evolution research due to their diversity of ecologies (including biphasic aquatic-terrestrial life cycles) that we hypothesize imposed different selective pressures leading to adaptive evolution of the visual system, notably the opsins that encode the protein component of the visual pigments responsible for the first step in visual perception.
View Article and Find Full Text PDFAntimicrobial peptides (AMPs) are key molecules in the innate immune defence of vertebrates with rapid action, broad antimicrobial spectrum, and ability to evade pathogen resistance mechanisms. To date, amphibians are the major group of vertebrates from which most AMPs have been characterised, but most studies have focused on the bioactive skin secretions of anurans (frogs and toads). In this study, we have analysed the complete genomes and/or transcriptomes of eight species of caecilian amphibians (order Gymnophiona) and characterised the diversity, molecular evolution, and antimicrobial potential of the AMP repertoire of this order of amphibians.
View Article and Find Full Text PDFUsing diffusible iodine-based contrast-enhanced computed tomography (diceCT), we examined the morphology of the oral glands of 12 species of the family Homalopsidae. Snakes of this family exhibit substantial interspecific morphological variation in their oral glands. Particular variables are the venom glands, ranging from large (e.
View Article and Find Full Text PDFThe shieldtail snake Rhinophis fergusonianus Boulenger, 1896 was previously known only from the holotype specimen collected approximately 130 years ago from an imprecise Indian locality (Cardamom Hills). We report the rediscovery of this species from four localities, from low-elevation hills on both sides of the Palghat Gap in the southern part of the Western Ghats of peninsular India. We document new specimens of R.
View Article and Find Full Text PDFA new species of the uropeltid snake genus Uropeltis Cuvier, 1829 is described from the environs of Munnar in the Anamalai hils of the Western Ghats of peninsular India. Uropeltis tricuspida sp. nov.
View Article and Find Full Text PDFHow do phenotypic associations intrinsic to an organism, such as developmental and mechanical processes, direct morphological evolution? Comparisons of intraspecific and clade-wide patterns of phenotypic covariation could inform how population-level trends ultimately dictate macroevolutionary changes. However, most studies have focused on analyzing integration and modularity either at macroevolutionary or intraspecific levels, without a shared analytical framework unifying these temporal scales. In this study, we investigate the intraspecific patterns of cranial integration in two squamate species: and .
View Article and Find Full Text PDFThe original description of (currently ) by Frank Wall in 1923, based on a specimen from the "Upper Burma Hills," lacked important morphological details that have complicated the assignment of recently collected material. Furthermore, although the holotype was never lost, its location has been misreported in one important taxonomic reference, leading to further confusion. We report the correct repository of the holotype (Natural History Museum, London), together with its current catalog number.
View Article and Find Full Text PDFUropeltis dindigalensis (Beddome, 1877) is a poorly known uropeltid (shieldtail) snake from peninsular India. Here we report morphological data for 14 preserved and nine uncollected specimens, most of which have not been previously reported. We designate a lectotype from the type series, describe it, and present the first published photographs of some of the type material.
View Article and Find Full Text PDFThe stylommatophoran land-snail genus Corilla is endemic to Sri Lanka and India's Western Ghats. On the basis of habitat distribution and shell morphology, the 10 extant Sri Lankan species fall into two distinct groups, lowland and montane. Here, we use phylogenetic analyses of restriction-site-associated DNA sequencing (RADseq) data and ancestral-state reconstructions of habitat association and shell morphology to clarify the systematics and evolution of Sri Lankan Corilla.
View Article and Find Full Text PDFThe concept of ecomorphs, whereby species with similar ecologies have similar phenotypes regardless of their phylogenetic relatedness, is often central to discussions regarding the relationship between ecology and phenotype. However, some aspects of the concept have been questioned, and sometimes species have been grouped as ecomorphs based on phenotypic similarity without demonstrating ecological similarity. Within snakes, similar head shapes have convergently evolved in species living in comparable environments and/or with similar diets.
View Article and Find Full Text PDFThe shape and relative size of an ocular lens affect the focal length of the eye, with consequences for visual acuity and sensitivity. Lenses are typically spherical in aquatic animals with camera-type eyes and axially flattened in terrestrial species to facilitate vision in optical media with different refractive indices. Frogs and toads (Amphibia: Anura) are ecologically diverse, with many species shifting from aquatic to terrestrial ecologies during metamorphosis.
View Article and Find Full Text PDFMyasthenia Gravis (MG) is mediated by autoantibodies against acetylcholine receptors that cause loss of the receptors in the neuromuscular junction. Eculizumab, a C5-inhibitor, is the only approved treatment for MG that mechanistically addresses complement-mediated loss of nicotinic acetylcholine receptors. It is an expensive drug and was approved despite missing the primary efficacy endpoint in the Phase 3 REGAIN study.
View Article and Find Full Text PDFWe report the rediscovery of Oligodon melaneus 112 years after its original description and document the third, and only non-type, specimen for the species. The new specimen was found 267 km east of the type locality (Tindharia, West Bengal state) from Assam state, India. We designate a lectotype for the species, and provide an extended description of a freshly collected male specimen.
View Article and Find Full Text PDFUrocotyledon inexpectata, a small gecko endemic to the granitic islands of the Seychelles, has previously been demonstrated to comprise two highly distinct clades based on mitochondrial and nuclear DNA sequences, with one lineage exclusive to a northern group of islands, and the second lineage exclusive to the more southerly islands. Here we complement the genetic data with additional analyses to determine if the clades should be considered distinct species. We present and analyse new morphological data, including skull and jaw osteology, and supplement the available genetic data with DNA sequences for individuals from the previously unsampled island of Felicit, which cluster with the other northern island samples.
View Article and Find Full Text PDFBackground: Differences in morphology, ecology, and behavior through ontogeny can result in opposing selective pressures at different life stages. Most animals, however, transition through two or more distinct phenotypic phases, which is hypothesized to allow each life stage to adapt more freely to its ecological niche. How this applies to sensory systems, and in particular how sensory systems adapt across life stages at the molecular level, is not well understood.
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