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Angele Martins - One of the best experts on this subject based on the ideXlab platform.
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moving beyond the surface comparative head and neck myology of threadsnakes epictinae leptotyphlopidae serpentes with comments on the Scolecophidian muscular system
PLOS ONE, 2019Co-Authors: Roberta R Pinto, Paulo Passos, Angele MartinsAbstract:Studies on the cephalic myology of snakes provide a series of relevant data on their biology and systematics. Despite the great amount of descriptive studies currently available for the group, much of the knowledge remains obscure for most Scolecophidian taxa. This study aimed to describe in detail the cephalic (head and neck) myology of members of the tribe Epictinae, Leptotyphlopidae. We provide the first report of the presence of extrinsic ocular muscles, and a double Musculus pterygoideus acessorius in Leptotyphlopidae. A well-developed M. levator anguli oris is exclusive to the subtribes Renina and Epictina, being reduced in Tetracheilostomina species. Both inter- and intraspecific variations are reported for the head and neck muscles, and such results provide additional data and raise an interesting discussion on the neck-trunk boundaries in snakes. We also provide a discussion on the terminology of a few head muscles in Leptoyphlopidae in comparison to the other lineages of ´Scolecophidia´ (Anomalepididae and Typhlopoidea).
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Unveiling diversity under the skin: comparative morphology study of the cephalic glands in threadsnakes (Serpentes: Leptotyphlopidae: Epictinae)
Zoomorphology, 2018Co-Authors: Angele Martins, Paulo Passos, Roberta PintoAbstract:The subfamily Epictinae contains about 75 currently recognized species of strictly fossorial snakes distributed along the Neotropics (subtribe Renina) and Equatorial Africa (subtribe Rhinoleptini). Although several studies have addressed some internal phenotypic characters complexes for the taxa included in this subfamily, most of the available data are limited to skull morphology and visceral topology. Additionally, many studies, when reporting glandular information, do not provide comparative data obtained through of a replicable methodology. In this study, we aimed to describe in detail the macrostructure of the cephalic glands for the members of the subfamily Epictinae. We provide herein the first report of a rictal gland for the infraorder Scolecophidia, as well as the first report of an infralabial accessory gland for the family Leptotyphlopidae. We highlight the utility of glandular qualitative characters for the systematics and even alpha taxonomy of this group of snakes that frequently exhibits a conserved external morphology. Furthermore, we also discuss possible functional aspects related to the Harderian gland in association to the M. adductor externus superficialis based on macrostructure observations of Epictinae specimens.
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osteology and cartilaginous elements of trilepida salgueiroi amaral 1954 Scolecophidia leptotyphlopidae
Anatomical Record-advances in Integrative Anatomy and Evolutionary Biology, 2015Co-Authors: Roberta R Pinto, Felipe Franco Curcio, Angele Martins, Luciana O RamosAbstract:Morphological and anatomical studies on the Leptotyphlopidae have increased in the past 10 years, providing important data on the systematics of this group, mainly focused on the skull and lower jaw morphology. However, most studies are based on a single specimen, rarely combining more than one single method of assessing morphological information. Therefore, several data on postcranial morphology, sexual dimorphism, and ontogenetic and intraspecific variation of leptotyphlopids remain poorly understood. Herein, we provide a detailed description of the cranial and postcranial skeleton of Trilepida salgueiroi based on more than 20 specimens (including males, females and juveniles), as well as a description of osteology and cartilaginous elements through the use of combined methodologies such as X-ray scanning, high resolution CT-scanning, and clearing and staining of articulated and disarticulated specimens. We also provide data on the presence/absence of dimorphic and intraspecific variation of the observed characters. The presence of a statolithic mass in the cavum vestibuli differs from the pattern found in other Scolecophidians. A correlation of dorsal vertebrae with ventral and subcaudal scales was found (1:1), as well as total number of vertebrae with middorsal scales (1:1), thoracolumbar vertebrae and ventral scales (1:1), and a higher number of caudal vertebra with subcaudal scales (1.23:1). Intraspecific variation was found in several elements of the skull, lower jaw, pelvic girdle and vertebral number, but no evidence of sexual dimorphism was found in any of the species characters analysed. The homologies of several elements are discussed, although still remaining poorly understood and unknown. Anat Rec, 298:1722–1747, 2015. © 2015 Wiley Periodicals, Inc.
Roberta R Pinto - One of the best experts on this subject based on the ideXlab platform.
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moving beyond the surface comparative head and neck myology of threadsnakes epictinae leptotyphlopidae serpentes with comments on the Scolecophidian muscular system
PLOS ONE, 2019Co-Authors: Roberta R Pinto, Paulo Passos, Angele MartinsAbstract:Studies on the cephalic myology of snakes provide a series of relevant data on their biology and systematics. Despite the great amount of descriptive studies currently available for the group, much of the knowledge remains obscure for most Scolecophidian taxa. This study aimed to describe in detail the cephalic (head and neck) myology of members of the tribe Epictinae, Leptotyphlopidae. We provide the first report of the presence of extrinsic ocular muscles, and a double Musculus pterygoideus acessorius in Leptotyphlopidae. A well-developed M. levator anguli oris is exclusive to the subtribes Renina and Epictina, being reduced in Tetracheilostomina species. Both inter- and intraspecific variations are reported for the head and neck muscles, and such results provide additional data and raise an interesting discussion on the neck-trunk boundaries in snakes. We also provide a discussion on the terminology of a few head muscles in Leptoyphlopidae in comparison to the other lineages of ´Scolecophidia´ (Anomalepididae and Typhlopoidea).
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osteology and cartilaginous elements of trilepida salgueiroi amaral 1954 Scolecophidia leptotyphlopidae
Anatomical Record-advances in Integrative Anatomy and Evolutionary Biology, 2015Co-Authors: Roberta R Pinto, Felipe Franco Curcio, Angele Martins, Luciana O RamosAbstract:Morphological and anatomical studies on the Leptotyphlopidae have increased in the past 10 years, providing important data on the systematics of this group, mainly focused on the skull and lower jaw morphology. However, most studies are based on a single specimen, rarely combining more than one single method of assessing morphological information. Therefore, several data on postcranial morphology, sexual dimorphism, and ontogenetic and intraspecific variation of leptotyphlopids remain poorly understood. Herein, we provide a detailed description of the cranial and postcranial skeleton of Trilepida salgueiroi based on more than 20 specimens (including males, females and juveniles), as well as a description of osteology and cartilaginous elements through the use of combined methodologies such as X-ray scanning, high resolution CT-scanning, and clearing and staining of articulated and disarticulated specimens. We also provide data on the presence/absence of dimorphic and intraspecific variation of the observed characters. The presence of a statolithic mass in the cavum vestibuli differs from the pattern found in other Scolecophidians. A correlation of dorsal vertebrae with ventral and subcaudal scales was found (1:1), as well as total number of vertebrae with middorsal scales (1:1), thoracolumbar vertebrae and ventral scales (1:1), and a higher number of caudal vertebra with subcaudal scales (1.23:1). Intraspecific variation was found in several elements of the skull, lower jaw, pelvic girdle and vertebral number, but no evidence of sexual dimorphism was found in any of the species characters analysed. The homologies of several elements are discussed, although still remaining poorly understood and unknown. Anat Rec, 298:1722–1747, 2015. © 2015 Wiley Periodicals, Inc.
Nicolas Vidal - One of the best experts on this subject based on the ideXlab platform.
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molecular evidence for the paraphyly of Scolecophidia and its evolutionary implications
Journal of Evolutionary Biology, 2018Co-Authors: Aurelien Miralles, Julie Marin, Damien Markus, Anthony Herrel, Blair S Hedges, Nicolas VidalAbstract:The phylogenetic relationships between the three main clades of worm snakes remain controversial. This question is, however, crucial to elucidate the origin of the successful snake radiation, as these burrowing and miniaturized wormlike organisms represent the earliest branching clades within the snake tree. The present molecular phylogenetic study, intended to minimize the amount of missing data, provides fully resolved inter-subfamilial relationships among Typhlopidae. It also brings robust evidence that worm snakes (Scolecophidia) are paraphyletic, with the Scolecophidian family Anomalepididae recovered with strong support as sister clade to the 'typical snakes' (Alethinophidia). Ancestral state reconstructions applied to three different traits strongly associated to a burrowing life-style (scolecoidy, absence of retinal cones and microstomy) provide results in favour of a burrowing origin of snakes, and suggest that worm snakes might be the only extant fossorial representatives of the primordial snake incursion towards an underground environment.
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worms in the sand systematic revision of the australian blindsnake anilios leptosoma robb 1972 species complex squamata Scolecophidia typhlopidae from the geraldton sandplain with description of two new species
Zootaxa, 2017Co-Authors: Ryan J Ellis, Julie Marin, Stephen C Donnellan, Paul Doughty, Nicolas VidalAbstract:The blindsnake genus Anilios (formerly Ramphotyphlops ) is the largest and most diverse genus of snakes in Australia with 45 currently recognized species. Recent molecular genetic studies of the genus have identified high levels of cryptic diversity within many taxa, suggesting true species diversity is greatly underestimated. Anilios leptosoma is a slender blindsnake endemic to the mid-west of Western Australia. Although morphological variation has been identified within the species in the past, the systematics and true diversity remained unstudied. Here we use recent molecular data to guide a reappraisal of morphology in order to provide a taxonomic revision of the A. leptosoma species complex. We redescribe A. leptosoma and describe two new species that occur to the south of most of true A. leptosoma ’s distribution: A. systenos sp. nov. and A. obtusifrons sp. nov. Anilios systenos sp. nov. is known from the Geraldton region with the furthest record only 100 km to the north-east, a very small range for a species of snake. Anilios obtusifrons sp. nov. has an even smaller distribution, as it is only known from a small coastal area south of Kalbarri and may represent a range-restricted taxa. All species are genetically divergent from each other and can be distinguished by consistent morphological characteristics, including the shape of the snout, the termination point of the rostral cleft and number of mid-body scale rows and ventral scales.
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hidden species diversity of australian burrowing snakes ramphotyphlops
Biological Journal of The Linnean Society, 2013Co-Authors: Julie Marin, Blair S Hedges, Stephen C Donnellan, Nicolas Puillandre, Ken Aplin, Paul Doughty, Mark N Hutchinson, Arnaud Couloux, Nicolas VidalAbstract:The worm-like snakes (Scolecophidia; approximately 400 nominal extant species) have a conservative morphology and are among the most poorly-known terrestrial vertebrates. Although molecular evidence has helped determine their higher-level relationships, such data have rarely been used to discriminate among species. We generated a molecular data set for the continental Australian blindsnakes (genus Ramphotyphlops) to determine the concordance of molecular and morphological information in the taxonomic recognition of species. Our dataset included 741 specimens morphologically attributed to 27 nominal Ramphotyphlops species. We proposed species hypotheses (SHs) after analysis of sequences from a variable mitochondrial gene (cytochrome b) and examined these SHs with additional evidence from a nuclear gene (prolactin receptor) and geographical data. Although the nuclear marker was not as fast-evolving and discriminating as the mitochondrial marker, there was congruence among the mitochondrial, nuclear, and geographical data, suggesting that the actual number of species is at least two times the current number of recognized, nominal species. Several biogeographical barriers and complex phytogeographical and geological patterns appeared to be involved in the division of some burrowing snake populations and, by consequence, in their diversification and speciation through isolation. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110, 427–441.
Van Wallach - One of the best experts on this subject based on the ideXlab platform.
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discovery of two rare specimens of ramphotyphlops serpentes Scolecophidia typhlopidae in the collection of the naturhistorisches museum wien
Russian Journal of Herpetology, 2019Co-Authors: Van Wallach, Richard GemelAbstract:Two rare Ramphotyphlops , described in 1934 and 1993 and known only from their respective types, are rediscovered among some unidentified, no data specimens in NMW. Brief descriptions and photographs are provided for these important specimens.
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systematics of the blindsnakes serpentes Scolecophidia typhlopoidea based on molecular and morphological evidence
Zootaxa, 2014Co-Authors: Robert Alexander Pyron, Van WallachAbstract:The blindsnake superfamily Typhlopoidea (Gerrhopilidae, Typhlopidae, and Xenotyphlopidae) is a diverse, widespread part of the global snake fauna. A recent systematic revision based on molecular phylogenetic analyses and some morphological evidence presented a preliminary solution to the non-monophyly of many previously recognized genera, but additional clarification is needed regarding the recognition of some species and genera. We rectify these problems here with a new molecular phylogenetic analysis including 95 of the 275 currently recognized, extant typhlopoids, incorporating both nuclear and mitochondrial loci. We supplement this with data on the external, visceral, and hemipenial morphology of nearly all species to generate a revised classification for Typhlopoidea. Based on morphological data, we re-assign Cathetorhinus from Typhlopidae to Gerrhopilidae. Xenotyphlopidae maintains its current contents ( Xenotyphlops ). In Typhlopidae, one monotypic genus is synonymized with its larger sister-group as it cannot be unambiguously diagnosed morphologically ( Sundatyphlops with Anilios ), and two genera are synonymizedwith Typhlops ( Antillotyphlops and Cubatyphlops ), as they are not reciprocally monophyletic. The genus Asiatyphylops is renamed Argyrophis, the senior synonym for the group. We erect one new genus ( Lemuriatyphlops ) for a phylogenetically distinct species-group in Asiatyphlopinae. Fourteen of eighteen recognized typhlopid genera are maintained in four subfamilies: Afrotyphlopinae ( Afrotyphlops, Grypotyphlops [re-assigned from Asiatyphlopinae] , Letheobia, and Rhinotyphlops ), Asiatyphlopinae ( Acutotyphlops, Anilios, Cyclotyphlops, Indotyphlops, Malayotyphlops, Ramphotyphlops, and Xerotyphlops ), Madatyphlopinae ( Madatyphlops ), and Typhlopinae ( Amerotyphlops and Typhlops ), some with altered contents. Diagnoses based on morphology are provided for all 19 typhlopoid genera, accounting for all 275 species. This taxonomy provides a robust platform for future revisions and description of new species.
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figure 3 approximate distribution maps for species from 7 in systematics of the blindsnakes serpentes Scolecophidia typhlopoidea based on molecular and morphological evidence
2014Co-Authors: Robert Alexander Pyron, Van WallachAbstract:FIGURE 3. Approximate distribution maps for species from 7 of 19 typhlopoid genera: Grypotyphlops, Letheobia, Lemuriatyphlops, Cyclotyphlops, Acutotyphlops, Afrotyphlops, and Ramphotyphlops.
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an enigmatic new species of blind snake from luzon island northern philippines with a synopsis of the genus acutotyphlops serpentes typhlopidae
Journal of Herpetology, 2007Co-Authors: Van Wallach, Rafe M Brown, Arvin C Diesmos, G V A GeeAbstract:Abstract We describe a strikingly distinct new species of Acutotyphlops from Kalinga Province of Luzon Island, Philippines. The new species is most closely related to other members of the genus Acutotyphlops from Papua New Guinea and the Solomon Islands and represents a new genus and species group record for the Philippines. A revised definition of Acutotyphlops is presented along with a synopsis of the genus. The discovery of this species, combined with consideration of its morphology and distribution, represents a curious new systematic and biogeographical problem in Southeast Asian and southwest Pacific Scolecophidian snake systematics.
Blair S Hedges - One of the best experts on this subject based on the ideXlab platform.
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molecular evidence for the paraphyly of Scolecophidia and its evolutionary implications
Journal of Evolutionary Biology, 2018Co-Authors: Aurelien Miralles, Julie Marin, Damien Markus, Anthony Herrel, Blair S Hedges, Nicolas VidalAbstract:The phylogenetic relationships between the three main clades of worm snakes remain controversial. This question is, however, crucial to elucidate the origin of the successful snake radiation, as these burrowing and miniaturized wormlike organisms represent the earliest branching clades within the snake tree. The present molecular phylogenetic study, intended to minimize the amount of missing data, provides fully resolved inter-subfamilial relationships among Typhlopidae. It also brings robust evidence that worm snakes (Scolecophidia) are paraphyletic, with the Scolecophidian family Anomalepididae recovered with strong support as sister clade to the 'typical snakes' (Alethinophidia). Ancestral state reconstructions applied to three different traits strongly associated to a burrowing life-style (scolecoidy, absence of retinal cones and microstomy) provide results in favour of a burrowing origin of snakes, and suggest that worm snakes might be the only extant fossorial representatives of the primordial snake incursion towards an underground environment.
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molecular systematics and undescribed diversity of madagascan Scolecophidian snakes squamata serpentes
Zootaxa, 2015Co-Authors: Zoltan Nagy, Frank Glaw, Miguel Vences, Aurelien Miralles, Angela B Marion, Joachim Nopper, Blair S HedgesAbstract:We provide an updated molecular phylogenetic analysis of global diversity of typhlopid and xenotyphlopid blindsnakes, adding a set of Madagascan samples and sequences of an additional mitochondrial gene to an existing supermatrix of nuclear and mitochondrial gene segments. Our data suggest monophyly of Madagascan typhlopids, exclusive of introduced Indotyphlops braminus. The Madagascar-endemic typhlopid clade includes two species previously assigned to the genus Lemuriatyphlops (in the subfamily Asiatyphlopinae), which were not each others closest relatives. This contradicts a previous study that described Lemuriatyphlops based on a sequence of the cytochrome oxidase subunit 1 gene from a single species and found this species not forming a clade with the other Malagasy species included. Based on our novel phylogenetic assessment we include all species in this endemic typhlopid clade in the genus Madatyphlops and in the subfamily Madatyphlopinae and consider Lemuriatyphlops as junior synonym. Within Madatyphlops, we identify several candidate species. For some of these (those in the M. arenarius complex), our preliminary data suggest sympatric occurrence and morphological differentiation, thus the existence of undescribed species. We also comment on the genus-level classification of several non-Madagascan typhlopids. We suggest that African species included in Madatyphlops (Afrotyphlops calabresii, A. cuneirostris, A. platyrhynchus, and Rhinotyphlops leucocephalus) should not be included in this genus. We furthermore argue that recent claims of Sundatyphlops, Antillotyphlops, and Cubatyphlops being "undiagnosable" or "not monophyletic" were based on errors in tree reconstruction and failure to notice diagnostic characters, and thus regard these three genera as valid.
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hidden species diversity of australian burrowing snakes ramphotyphlops
Biological Journal of The Linnean Society, 2013Co-Authors: Julie Marin, Blair S Hedges, Stephen C Donnellan, Nicolas Puillandre, Ken Aplin, Paul Doughty, Mark N Hutchinson, Arnaud Couloux, Nicolas VidalAbstract:The worm-like snakes (Scolecophidia; approximately 400 nominal extant species) have a conservative morphology and are among the most poorly-known terrestrial vertebrates. Although molecular evidence has helped determine their higher-level relationships, such data have rarely been used to discriminate among species. We generated a molecular data set for the continental Australian blindsnakes (genus Ramphotyphlops) to determine the concordance of molecular and morphological information in the taxonomic recognition of species. Our dataset included 741 specimens morphologically attributed to 27 nominal Ramphotyphlops species. We proposed species hypotheses (SHs) after analysis of sequences from a variable mitochondrial gene (cytochrome b) and examined these SHs with additional evidence from a nuclear gene (prolactin receptor) and geographical data. Although the nuclear marker was not as fast-evolving and discriminating as the mitochondrial marker, there was congruence among the mitochondrial, nuclear, and geographical data, suggesting that the actual number of species is at least two times the current number of recognized, nominal species. Several biogeographical barriers and complex phytogeographical and geological patterns appeared to be involved in the division of some burrowing snake populations and, by consequence, in their diversification and speciation through isolation. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110, 427–441.
