Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Resultados 1 - 20 de 36
Filtrar
1.
J Anim Ecol ; 92(2): 324-337, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36059124

RESUMEN

Studying species interactions in nature often requires elaborated logistics and intense fieldwork. The difficulties in such task might hinder our ability to answer questions on how biotic interactions change with the environment. Fortunately, a workaround to this problem lies within scientific collections. For some animals, the inspection of preserved specimens can reveal the scars of past antagonistic encounters, such as predation attempts. A common defensive behaviour that leaves scars on animals is autotomy, the loss of a body appendage to escape predation. By knowing the collection site of preserved specimens, it is possible to assess the influence of organismal biology and the surrounding environment in the occurrence of autotomy. We gathered data on tail loss for 8189 preserved specimens of 33 snake and 11 amphisbaenian species to investigate biological and environmental correlates of autotomy in reptiles. We applied generalized linear mixed effect models to evaluate whether body size, sex, life-stage, habitat use, activity pattern, biome, tropicality, temperature and precipitation affect the probability of tail loss in limbless reptiles. We observed autotomy in 23.6% of examined specimens, with 18.7% of amphisbaenian and 33.4% of snake specimens showing tail loss. The probability of tail loss did not differ between snakes and amphisbaenians, but it was higher among large-sized specimens, particularly in adults and females. Chance of tail loss was higher for diurnal and arboreal species, and among specimens collected in warmer regions, but it was unaffected by biome, precipitation, and tropicality. Autotomy in limbless reptiles was affected by size-dependent factors that interplay with ontogeny and sexual dimorphism, although size-independent effects of life-stage and sex also shaped behavioural responses to predators. The increase in probability of tail loss with verticality and diurnality suggests a risk-balance mechanism between species habitat use and activity pattern. Although autotomy is more likely in warmer regions, it seems unrelated to seasonal differences in snakes and amphisbaenians activity. Our findings reveal several processes related to predator-prey interactions involving limbless reptiles, demonstrating the importance of scientific collections to unveil ecological mechanisms at different spatio-temporal scales.


Asunto(s)
Lagartos , Femenino , Animales , Lagartos/fisiología , Cola (estructura animal)/fisiología , Conducta Predatoria , Cicatriz , Ecosistema
2.
An Acad Bras Cienc ; 95(3): e20230222, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37878915

RESUMEN

A series of specimens of an unidentified species of the genus Lygodactylus from Fernando de Noronha Island were found in the herpetological collections of the Museu Nacional, Rio de Janeiro (Brazil). No species of this genus were known to occur in the archipelago. A review of the historical reports regarding the herpetofauna of the island failed to provide evidence regarding the presence of the species in the last centuries. Morphological comparisons with the two other species of the genus occurring in South America, L. klugei and L. wetzeli, allowed us to confidently confirm that the Fernando de Noronha population belonged to a putatively new species. Here we describe this population as a new species and discuss its possible extinction causes in the archipelago. We also debate the importance of historical natural history collections to the study of biodiversity.


Asunto(s)
Lagartos , Animales , Brasil/epidemiología
3.
An Acad Bras Cienc ; 94(1): e20191254, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35043846

RESUMEN

Atractus badius has a long and controversial nomenclatural history due to both its antiquity and the brevity of its original description. This species was described based on two syntypes from Java. Later, a lectotype was designated and the distribution range restricted to the Guiana Shield. Although this species has been repeatedly recorded throughout Amazonia and the Andes, these records have been erroneously assigned to A. badius because of a considerable level of confusion in the literature. We found 13 additional specimens of this poorly known snake, expanding our knowledge on its morphological variability, phylogenetic relationships and distribution. In this paper, we report new localities and data on meristic, morphometric, coloration, scales micro-ornamentation, osteology and hemipenial morphology to A. badius. We also determine the phylogenetic position of A. badius as nested in a composite Guiana Shield clade. In addition, we discuss recent advances on the systematics of Atractus and comment on some 'new arrangements' with respect to previously recognized species groups and available morphological evidence. Finally, we highlight the importance of accurate voucher identification before promoting taxonomic changes or implementing nomenclatural acts derived from new phylogenetic hypotheses, and notably propose the synonymy of the recently described A. pyroni with A. roulei.


Asunto(s)
Genómica , Serpientes , Animales , Brasil , Osteología , Filogenia , Serpientes/genética
4.
An Acad Bras Cienc ; 91(suppl 1): e20170976, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-29791565

RESUMEN

Body-size is significantly correlated with the number of vertebrae (pleomerism) in multiple vertebrate lineages, indicating that somitogenesis process is an important factor dictating evolutionary change associated to phyletic allometry and, consequently, species fitness and diversification. However, the role of the evolution of extreme body sizes (dwarfism and gigantism) remains elusive in snakes, mainly with respect to postnatal ontogeny in dietary preferences associated with evolution of gigantism in many lineages. We described herein a new species in the highly diversified and species-rich genus Atractus on the basis of four specimens from the southeastern slopes of the Ecuadorian Andes. The new species is morphologically similar and apparently closely related to two other allopatric giant congeners (A. gigas and A. touzeti), from which it can be distinguished by their distinct dorsal and ventral coloration, the number of supralabial and infralabial scales, the number of maxillary teeth, and relative width of the head. In addition, we discuss on the ontogenetic trajectories hypotheses and dietary specializations related to evolution of gigantism in the goo-eaters genus Atractus.


Asunto(s)
Tamaño Corporal , Conducta Alimentaria/fisiología , Serpientes/anatomía & histología , Animales , Evolución Biológica , Ecuador , Femenino , Serpientes/clasificación , Serpientes/fisiología
5.
Glob Ecol Biogeogr ; 27(1): 14-21, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-29398972

RESUMEN

Motivation: We generated a novel database of Neotropical snakes (one of the world's richest herpetofauna) combining the most comprehensive, manually compiled distribution dataset with publicly available data. We assess, for the first time, the diversity patterns for all Neotropical snakes as well as sampling density and sampling biases. Main types of variables contained: We compiled three databases of species occurrences: a dataset downloaded from the Global Biodiversity Information Facility (GBIF), a verified dataset built through taxonomic work and specialized literature, and a combined dataset comprising a cleaned version of the GBIF dataset merged with the verified dataset. Spatial location and grain: Neotropics, Behrmann projection equivalent to 1° × 1°. Time period: Specimens housed in museums during the last 150 years. Major taxa studied: Squamata: Serpentes. Software format: Geographical information system (GIS). Results: The combined dataset provides the most comprehensive distribution database for Neotropical snakes to date. It contains 147,515 records for 886 species across 12 families, representing 74% of all species of snakes, spanning 27 countries in the Americas. Species richness and phylogenetic diversity show overall similar patterns. Amazonia is the least sampled Neotropical region, whereas most well-sampled sites are located near large universities and scientific collections. We provide a list and updated maps of geographical distribution of all snake species surveyed. Main conclusions: The biodiversity metrics of Neotropical snakes reflect patterns previously documented for other vertebrates, suggesting that similar factors may determine the diversity of both ectothermic and endothermic animals. We suggest conservation strategies for high-diversity areas and sampling efforts be directed towards Amazonia and poorly known species.

6.
PLoS One ; 19(4): e0298159, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38630841

RESUMEN

Snakes of the genus Boa are outstanding elements of the New World biota with a broad sociological influence on pop culture. Historically, several taxa have been recognized in the past 300 years, being mostly described in the early days of binomial nomenclature. As a rule, these taxa were recognized based on a suite of phenotypic characters mainly those from the external morphology. However, there is a huge disagreement with respect to the current taxonomy and available molecular phylogenies. In order to reconcile both lines of evidence, we investigate the phylogenetic reconstruction (using mitochondrial and nuclear genes) of the genus in parallel to the detailed study of some phenotypic systems from a geographically representative sample of the cis-Andean mainland Boa constrictor. We used cyt-b only (744bp) from 73 samples, and cyt-b, ND4, NTF3, and ODC partial sequences (in a total of 2305 bp) from 35 samples, comprising nine currently recognized taxa (species or subspecies), to infer phylogenetic relationships of boas. Topologies recovered along all the analyses and genetic distances obtained allied to a unique combination of morphological traits (colouration, pholidosis, meristic, morphometric, and male genitalia features) allowed us to recognize B. constrictor lato sensu, B. nebulosa, B. occidentalis, B. orophias and a distinct lineage from the eastern coast of Brazil, which we describe here as a new species, diagnosing it from the previously recognized taxa. Finally, we discuss the minimally necessary changes in the taxonomy of Boa constrictor complex; the value of some usually disregarded phenotypic character system; and we highlight the urgency of continuing environmental policy to preserve one of the most impacted Brazilian hotspots, the Atlantic Forest, which represents an ecoregion full of endemism.


Asunto(s)
Boidae , Lepidópteros , Animales , Masculino , Filogenia , Boidae/genética , Mitocondrias/genética , Brasil
7.
Sci Rep ; 14(1): 8446, 2024 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-38600186

RESUMEN

Acting as a goalkeeper in a video-game, a participant is asked to predict the successive choices of the penalty taker. The sequence of choices of the penalty taker is generated by a stochastic chain with memory of variable length. It has been conjectured that the probability distribution of the response times is a function of the specific sequence of past choices governing the algorithm used by the penalty taker to make his choice at each step. We found empirical evidence that besides this dependence, the distribution of the response times depends also on the success or failure of the previous prediction made by the participant. Moreover, we found statistical evidence that this dependence propagates up to two steps forward after the prediction failure.

8.
Zootaxa ; 3745: 35-48, 2013 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-25113336

RESUMEN

Atractus caxiuana was recently described based on three specimens (two males and one female) from the Floresta Nacional de Caxiuanã, municipality of Melgaço, state of Pará, in the eastern portion of the Brazilian Amazon. Apart from the type series, no additional samples are known for the species. In this study, we report new specimens of A. caxiuana, providing new morphological data (meristic, morphometric, pholidosis, colour pattern, and hemipenis) and localities. We relate the variability displayed by the characters analyzed to sexual dimorphism, geographic variation, and ontogeny. Additionally, we provide detailed comparisons with A. collaris and putative sister species, and propose a new species group to accommodate this distinct and possible monophyletic assemblage. 


Asunto(s)
Colubridae/anatomía & histología , Colubridae/clasificación , Distribución Animal , Estructuras Animales/anatomía & histología , Animales , Brasil , Ecosistema , Femenino , Masculino
9.
Zootaxa ; 3721: 455-74, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-26120686

RESUMEN

We describe a new species of Atractus from Cordillera de los Guacamayos in the Andes of Ecuador. This new species is the largest known species of Atractus, reaching almost 120 cm in total length with a robust habitus. We also use multivariate statistical analyses of morphometric data to look into the taxonomic confusion involving other large, banded/blotched, species of Atractus in Western Amazonia. We show that A. snethlageae has a widespread distribution in Amazonia and has been repeatedly confused with A. major in Ecuador owing to its color polymorphism. Our multivariate statistical analyses support previous suggestions to recognize A. snethlageae as a distinct species relative to A. flammigerus. Taxonomic accounts are provided for both A. major and A. snethlageae including detailed color pattern descriptions. We also find that there are no valid morphological differences to support recognizing A. arangoi as a separate species from A. major; consequently we synonymize the former name with the latter.


Asunto(s)
Colubridae/clasificación , Distribución Animal , Estructuras Animales/anatomía & histología , Estructuras Animales/crecimiento & desarrollo , Animales , Tamaño Corporal , Colubridae/anatomía & histología , Colubridae/crecimiento & desarrollo , Ecuador , Femenino , Hábitos , Masculino
10.
Zootaxa ; 5244(2): 123-144, 2023 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-37044473

RESUMEN

Wagler described Natrix sexcarinata through a specimen collected on the banks of the Amazon River in Brazil, without citing a specific location. The species was later transferred to different Neotropical genera (Chironius, Herpetodryas, Phrynonax, and Pseustes) currently allocated in the Family Colubridae. The taxonomic instability of Natrix sexcarinata is probably due to its brief original description in combination with its supposedly inaccurate illustration. Despite the holotype being lost during World War II, some authors have pointed out that its description is somewhat similar to the widespread concept of Pseustes poecilonotus. More recently, a molecular study proposed the synonymy of the genera Pseustes with Spilotes, resurrecting the Phrynonax genus to allocate Ph. poecilonotus and Ph. polylepis. However, the taxonomic positioning of Natrix sexcarinata remains unsatisfactory with respect to the cis-Andean taxa placed in Phrynonax or even Spilotes throughout the Amazon. Considering the taxonomic and nomenclatural problems mentioned above, we investigated how many Phrynonax species occur along the Amazon Basin and what would be their applicable name. We examined the external morphology (meristic, morphometric, and color pattern data) of 118 Phrynonax specimens and prepared the hemipenes of seven specimens to understand geographic, sexual, and ontogenetic variability parameters. Our result suggests the synonymy of Ph. polylepis and N. sexcarinata under the combination Phrynonax sexcarinatus. Based on available evidence, we reinforce that Phrynonax sexcarinatus is the only congener that occurs along the Amazon Basin. We have also designated a Natrix sexcarinata neotype to stabilize its complex nomenclature.


Asunto(s)
Colubridae , Animales , Colubridae/clasificación , Ríos
11.
Zootaxa ; 4941(2): zootaxa.4941.2.6, 2021 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-33756942

RESUMEN

Corallus hortulana presents a large array of tones and color pattern variability throughout its distribution (= polychromatism), which trigged the description of several taxa now considered to be primary synonyms. Linnaeus described two of these (Boa enydris and Boa hortulana) on the same page of the 10th Edition of the Systema Naturae. However, both names had been widely used in literature almost in an optional way, until their formal synonymization more than two centuries after the original description. Additionally, the type specimen of Boa hortulana was reported as missing since the late 19th century. These two factors may have enabled the unjustified switched association of types, which was perpetuated in the literature to the present day. Our main goals here were to trace the correct type specimens for each species through a literature review and specimen examination, and to amend the switched association of type material. We found two specimens in the collection of the Uppsala University that are unmistakably associated with Boa hortulana. Herein we designate one of them as its lectotype in order to promote nomenclatural stability considering its huge phenotypic variability and the future possibility of eventually splitting the species.


Asunto(s)
Boidae , Animales , Árboles
12.
Anat Rec (Hoboken) ; 304(10): 2183-2197, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34101371

RESUMEN

Since the rearrangement of all leptotyphlopid species previously known as "Leptotyphlops" in Adalsteinsson et al. (2009)'s paper, several taxa have remained untested regarding their generic identity and have been assigned to different genera based on phenotypic data or, in some cases, without any clear justification. Most of the difficulties in assigning some leptotyphlopid taxa are due to their conserved external morphology, summed with a relatively small number of available specimens, which complicate the recognition of a unique combination of characters for their reasonable generic allocation. On the other hand, recent osteological studies-especially those on the skull-provide relevant data combinations for species assignment and even for the recognition of new genera. In this work, we have attempted to determine the generic allocation of Epictia unicolor and Trilepida guayaquilensis-both species currently known only by their holotype-based on a detailed description of cranial and post-cranial osteology. We confirm the assignment of E. unicolor to the genus Epictia despite the divergent configuration of cephalic shields. Based mainly on data from the skull, suspensorium, and cervical vertebrae but supported by external morphology as well as a redescription of the holotype, we propose the assignment of Trilepida guayaquilensis to the genus Epictia. This study provides not only detailed data on the osteology of Epictia, but also a first approach to the putative combination of osteological characters for the genus.


Asunto(s)
Osteología , Serpientes , Animales
13.
Anat Rec (Hoboken) ; 304(10): 2149-2182, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34448543

RESUMEN

The threadsnakes of the family Leptotyphlopidae have been historically neglected in terms of their natural history, ecology, systematics, and morphology. Given the relevance of morphological data for resolving systematic, evolutionary, and functional issues, we aimed to provide a detailed comparative description of osteology and associated cartilaginous elements for members of the genus Trilepida. Data were obtained through high-resolution computed tomography images, cleared and stained specimens, and radiography images of a total of 47 specimens and 12 species. Both cranial and axial osteology characters exhibited a relevant degree of intraspecific variation regarding qualitative and quantitative data associated with skull and vertebrae foramina and the shape of bony sutures and processes. The high representativeness of examined species and specimens allows us to provide a comprehensive discussion on the inter- and intraspecific osteological variation, as well as a compelling osteological diagnosis for the entire genus. Trilepida spp. differ from all Epictinae by the presence of the following combination of characters: paired nasals, fused supraoccipitals (distinct from parietal, prootics, and otooccipitals), a single (fused) parietal without a dorsal fontanelle, and the basioccipital participating in the foramen magnum (except in Trilepida nicefori). Our results reinforce the need for integration of detailed anatomical traits to usually conserved external morphological data to provide accurate diagnostic features for Epictinae. In addition, new phylogenetic hypotheses or even taxonomic re-allocations may broadly benefit from these detailed comparative studies.


Asunto(s)
Ecología , Osteología , Serpientes , Animales , Filogenia
14.
Anat Rec (Hoboken) ; 304(10): 2118-2148, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34296825

RESUMEN

The genera Mitophis and Tetracheilostoma comprise two extant lineages of small-sized threadsnakes that exclusively inhabit several islands of the West Indies. Even though leptotyphlopids are known for their extremely reduced size, miniaturization has only been hypothesized to reflect insular dwarfism for the genus Tetracheilostoma. Herein, we aim to describe the comparative osteology and visceral morphology of both genera, investigating and discussing their several internal morphological simplifications and novelties. Our results indicate that these taxa exhibit several autapomorphies mostly concentrated in the dorsoposterior skull elements and maxillae, as well as in their axial skeleton and viscera. These novelties and simplifications are most likely a result of extreme miniaturization driven by the evolutionary constraints or ecological opportunities possibly imposed by the "island rule." Both Mitophis and Tetracheilostoma distinguish from all other Epictinae in lacking a dentigerous process in the maxillae, by having the prootic fused to the otooccipital, and by the lack (except in comparison to a few Epictia) of a cervical vertebrae intercentrum I. Additionally, Mitophis can be distinguished from other Epictinae by the participation of the unpaired supraoccipital in the dorsal border of the foramen magnum, by the absence of the pleurapophyses in the caudal vertebrae, by a higher number of liver segments, and by the extreme degeneration of the pelvic rudiments. Tetracheilostoma differs from other Epictinae by lacking a distinct supraoccipital, which is fused to the parietal. Thus, our results reinforce that morphological characters are extremely valuable for leptotyphlopid systematics given their extremely conserved external morphology.


Asunto(s)
Osteología , Investigación , Miniaturización , Indias Occidentales
15.
Zootaxa ; 4979(1): 1722, 2021 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-34186995

RESUMEN

There are currently 3,900 recognized, extant snake species belonging to 529 genera globally (Uetz et al. 2021; this study), making snakes one of the most diverse major groups of squamates. Of the 665 currently recognized species that were described between 2001 and 2020 (a ~17% increase in total species), ~34% of these (226 species) were described in Zootaxa. This number does not include species resurrected from synonymy. The other ~66% (439) species were described in 105 other journals, bulletins or books (Fig.1a). Overall, the number of new snake species described every year is gradually increasing, and 40% of the new species described since 2011 were published in Zootaxa. Following Zootaxa, the second ranked journal, with 37 described species since 2001, is Herpetologica (Fig. 2). Anecdotally, the choice of Zootaxa as a publication outlet for new species descriptions by most authors is based on speed of publication post-acceptance, publication free of charge, relatively unconstrained number of papers published per year, relatively unconstrained manuscript length, expert section editors and reviewers, and consolidated scientometric parameters.


Asunto(s)
Publicaciones Periódicas como Asunto , Serpientes/clasificación , Animales , Bibliometría
16.
Int J Stroke ; 16(1): 100-109, 2021 01.
Artículo en Inglés | MEDLINE | ID: mdl-31793395

RESUMEN

BACKGROUND: RESILIENT is a prospective, multicenter, randomized phase III trial to test the safety, efficacy, and cost-effectiveness of mechanical thrombectomy as compared to medical treatment alone in patients treated under the less than ideal conditions typically found in the public healthcare system of a developing country. METHODS: Subjects must fulfill the following main inclusion criteria: symptom onset ≤8 h, age ≥18 years, baseline NIHSS ≥8, evidence of intracranial ICA or proximal MCA (M1 segment) occlusion, ASPECTS ≥6 on CT or >5 on DWI-MRI and be either ineligible for or unresponsive to intravenous alteplase. The primary end-point is the distribution of disability levels (on the modified Rankin Scale, mRS) at 90 days under the intention-to-treat principle. RANDOMIZATION: Randomization is performed under a minimization process using age, baseline NIHSS, intravenous alteplase use, occlusion site and center. DESIGN: The trial is designed with an expectation of a 10% difference in the proportion of favorable outcome (mRS 0-2 at 90 days) common odds ratio of 1.615. PRIMARY OUTCOME: Projected sample size is 690 subjects with pre-planned interim analyses at 174, 346, and 518 subjects. SECONDARY OUTCOMES: Secondary end-points include: 90-day functional independence (mRS ≤2), mRS shift stratified for treatment with IV rt-PA at 90 days, infarct volume on 24 h CT or MRI, early dramatic response (NIHSS 0-2 or improvement ≥8 points) at 24 h, vessel recanalization evaluated by CTA or MRA at 24 h, and the post-procedure rate of successful reperfusion (defined as a modified Treatment in Cerebral Infarction 2b or greater). Safety variables are mortality at 90 days, symptomatic intracranial hemorrhage at 24 h and procedure-related complications.


Asunto(s)
Isquemia Encefálica , Procedimientos Endovasculares , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Adolescente , Isquemia Encefálica/complicaciones , Isquemia Encefálica/tratamiento farmacológico , Humanos , Estudios Prospectivos , Distribución Aleatoria , Stents , Accidente Cerebrovascular/tratamiento farmacológico , Trombectomía , Resultado del Tratamiento
17.
PLoS One ; 15(12): e0243210, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33306700

RESUMEN

A reliable identification and delimitation of species is an essential pre-requisite for many fields of science and conservation. The Neotropical herpetofauna is the world's most diverse, including many taxa of uncertain or debated taxonomy. Here we tackle one such species complex, by evaluating the taxonomic status of species currently allocated in the snake genus Xenopholis (X. scalaris, X. undulatus, and X. werdingorum). We base our conclusions on concordance between quantitative (meristic and morphometric) and qualitative (color pattern, hemipenes and skull features) analyses of morphological characters, in combination with ecological niche modeling. We recognize all three taxa as valid species and improve their respective diagnosis, including new data on color in life, pholidosis, bony morphology, and male genitalia. We find low overlap among the niches of each species, corroborating the independent source of phenotypic evidence. Even though all three species occur in the leaf litter of distinct forested habitats, Xenopholis undulatus is found in the elevated areas of the Brazilian Shield (Caatinga, Cerrado and Chaco), whereas X. scalaris occurs in the Amazon and Atlantic rainforests, and X. werdingorum in the Chiquitanos forest and Pantanal wetlands. We discuss the disjunct distribution between Amazonian and Atlantic Forest snake species in the light of available natural history and ecological aspects. This study shows the advantages of combining multiple data sources for reliable identification and circumscription of ecologically similar species.


Asunto(s)
Colubridae/clasificación , Animales , Colubridae/anatomía & histología , Ecosistema , Femenino , Genitales/anatomía & histología , Masculino , Cráneo/anatomía & histología , América del Sur
18.
PLoS One ; 14(7): e0219661, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31318886

RESUMEN

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).


Asunto(s)
Sistema Musculoesquelético/anatomía & histología , Cuello/anatomía & histología , Serpientes/anatomía & histología , Animales , Cabeza , Especificidad de la Especie
19.
PloS One, v. 19, n. 4, e0298159, abr. 2024
Artículo en Inglés | SES-SP, SES SP - Instituto Butantan, SES-SP | ID: bud-5316

RESUMEN

Snakes of the genus Boa are outstanding elements of the New World biota with a broad sociological influence on pop culture. Historically, several taxa have been recognized in the past 300 years, being mostly described in the early days of binomial nomenclature. As a rule, these taxa were recognized based on a suite of phenotypic characters mainly those from the external morphology. However, there is a huge disagreement with respect to the current taxonomy and available molecular phylogenies. In order to reconcile both lines of evidence, we investigate the phylogenetic reconstruction (using mitochondrial and nuclear genes) of the genus in parallel to the detailed study of some phenotypic systems from a geo graphically representative sample of the cis-Andean mainland Boa constrictor. We used cyt b only (744bp) from 73 samples, and cyt-b, ND4, NTF3, and ODC partial sequences (in a total of 2305 bp) from 35 samples, comprising nine currently recognized taxa (species or subspecies), to infer phylogenetic relationships of boas. Topologies recovered along all the analyses and genetic distances obtained allied to a unique combination of morphological traits (colouration, pholidosis, meristic, morphometric, and male genitalia features) allowed us to recognize B. constrictor lato sensu, B. nebulosa, B. occidentalis, B. orophias and a dis tinct lineage from the eastern coast of Brazil, which we describe here as a new species, diagnosing it from the previously recognized taxa. Finally, we discuss the minimally neces sary changes in the taxonomy of Boa constrictor complex; the value of some usually disre garded phenotypic character system; and we highlight the urgency of continuing environmental policy to preserve one of the most impacted Brazilian hotspots, the Atlantic Forest, which represents an ecoregion full of endemism.

20.
Zootaxa ; 4438(1): 176-182, 2018 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-30313164

RESUMEN

The genus Atractus Wagler 1828 comprises almost 150 currently recognized species of cryptozoic snakes widespread in the Neotropics, occurring from Panama to northeastern Argentina (Passos et al. 2016a). Despite the publication of the descriptions of several new species within the last decade, the taxonomy of the genus is unclear in some instances. This is mainly due to the fact that a number of poorly delimited taxa still exist (Passos et al. 2018). The most frequent problem faced by taxonomist working with the genus Atractus is the lack of specimens available for several species, most of them only still being known from their types, a situation that considerably weakens the definition of species boundaries between closely related taxa (Passos et al. 2010a, 2013). More importantly, many of the previously recognized species may represent aberrant individuals with unusual or abnormal scale counts, anomalous azygous or fused cephalic plates, infrequent polychromatic patterns, or any combination of these states (see Passos et al. 2016b). In the course of a thorough taxonomic review of the genus (Passos 2008; Passos et al. 2018), an effort has been made to examine all of the available types (including those apparently lost or misplaced in collections) and material of historical importance that was previously referred to the genus in the literature, and these were then compared to newer samples collected more recently. During the examination of the collections of the Natural History Museum of London and the Museo Civico di Storia Naturale of Genova, we found important specimens of Atractus from Bolivia. However, in order to better understand all the problems related to these old and "forgotten" Bolivian snakes, we need to examine their history.


Asunto(s)
Serpientes , Animales , Bolivia
SELECCIÓN DE REFERENCIAS
Detalles de la búsqueda