Increasing taxon sampling suggests a complete taxonomic rearrangement in Echinantherini (Serpentes: Dipsadidae)

Although the recent advances on the relationship of its major groups, the systematics of the rich fauna of Neotropical snakes is far from being a consensus. In this sense, derived groups presenting continental distributions have represented a main challenge. The taxonomy of the snake tribe Echinantherini is one of the most contentious among the diverse family known as Dipsadidae. The tribe is poorly sampled in phylogenetic studies, resulting in conflicting hypotheses of relationships among its taxa. Moreover, several rare and micro endemic species of Echinantherini have never been evaluated within a comprehensive phylogenetic framework. Here, we assess for the first time the phylogenetic position of the rare Echinanthera amoena within Echinantherini. We based our analyses on a comprehensive multilocus dataset including 14 of the 16 species described for the tribe. Our results support the monophyly of Echinantherini and strongly indicate E. amoena as a unique lineage, phylogenetically positioned apart from all other congeners. From the three current genera (Echinanthera, Taeniophallus, and Sordellina) our results indicate that Echinanthera and Taeniophallus are paraphyletic, since the T. affinis species group is positioned as sister to Echinanthera (except E. amoena) clustering apart from the clade formed by the T. brevirostris and T. occipitalis groups. We describe new genera for the T. affinis and T. occipitalis species groups and an additional monospecific genus for E. amoena. Although we did not evaluate the phylogenetic position of T. nebularis, we described a new genus and removed it from Echinantherini since its morphology strikingly departs from all species now included in the tribe. Finally, we redefine the genera Echinanthera and Taeniophallus and we provide comments about further directions to study the biogeography and the evolution of morphological traits in Echinantherini.

Reassessment of Tantilla boipiranga (Serpentes: Colubrinae) and a preliminary approach to the phylogenetic affinities within Tantilla

Tantilla is one of the most diverse genera among colubrids, with 67 species arranged in six phenotypically recognized species groups. Tantilla boipiranga is the most recently described species within the T. melanocephala group, and it was described based on a small type series, collected in the rupestrian grasslands of south-eastern Brazil. The morphological diversity and the phylogenetic affinity of this species remain poorly known. Here, based on the assessment of recently collected specimens in combination with results of a molecular phylogenetic analysis, we evaluate the morphological variation within T. boipiranga and its phylogenetic position. Our analyses confirm T. boipiranga as genetically distinct from its generic counterparts, and diagnosable based on a combination of colour pattern, meristic counts, and hemipenial morphology. However, contrary to its original description, the hemipenial ornamentation does not differen-tiate T. boipiranga from the highly variable T. melanocephala. In our phylogenetic analysis, T. boipiranga is retrieved as a monophyletic group, nested within the diversity of T. melanocephala and sister to a clade composed by specimens from south-eastern Brazil. Tantilla melanocephala is recovered as a highly diverse lineage, indicating the possible presence of undescribed species. Additionally, our analysis indicates that the T. coronata and T. planiceps species group are mono-phyletic, while the T. taeniata species group is paraphyletic and the only sampled species for the T. calamarina group is nested within the T. melanocephala group. Our results suggest that the phenotypic evolution within the genus is probably more complex than previously recognized, and some colouration patterns used to define the groups can in fact represent phenotypical convergences. Moreover, our phylogenetic analysis suggests a strong signal of geographical structure in the tree topology. Three main geographical lineages were found, a North American, a South American and a Central Ameri-can. The first two lineages were recovered as monophyletic, while the latter is paraphyletic, with Central American species positioned as sister groups of both, the North American and the South American clades. Although a more comprehensive phylogenetic analysis is needed, our study strongly indicates the existence of hidden diversity within the T. melanocephala group and that Tantilla represents an ideal model to evaluate the validity of phenotypical groups in snake systematics and to study the driven mechanisms of morphological evolution.

A new species of Erythrolamprus (Serpentes: Dipsadidae: Xenodontini) from the savannas of northern South America

Erythrolamprus Boie, 1826 is a highly diverse dipsadid snake genus, ranging from Central America south to Argentina and Uruguay. In this work, we reassess the taxonomic status of specimens previously identified as Erythrolamprus poecilogyrus schotti (Schlegel, 1837) from the savannah habitats of Roraima state, northern Brazil, Guyana, and Bolívarstate, Venezuela. Based on novel molecular and morphological evidence, we conclude that these specimens represent a distinct, diagnosable and reciprocally monophyletic taxon. We here describe it as a new species. Furthermore, we comment on the taxonomy of other Erythrolamprus spp

Extraordinary claims require extraordinary evidence: on the taxonomic identity of Phalotris cerradensis Silveira, 2020

Phalotris Cope, 1862 is a fossorial dipsadid snake genus that encompasses 15 species, distributed mainly in open areas from Northeastern Brazil to Southern Argentina. Some of its species are known from small series, and there is little to no knowledge on their morphological variation and species delimitations. In this work, we analyze the taxonomic status of Phalotris cerradensisSilveira, 2020, a recently described species known from a single specimen, and provide evidence for its synonymy with Phalotris concolorFerrarezzi, 1993.

Sexual dimorphism, ontogeny and static allometry of a semi-fossorial snake (genus Atractus)

Sexual dimorphism in snakes has been mainly evaluated for size and number of some morphological traits, but few studies address on sexual shape dimorphism. Here we evaluated the existence of sexual size and shape dimorphism in the semi-fossorial snake Atractus reticulatus. We use linear and geometric morphometrics to evaluate differences between sexes and among different ontogenetic stages (neonates, juveniles and adults). We have shown that A. reticulatus is sexually dimorphic for some traits such as body length and head shape, with females being larger and having more robust heads than males, but the sexes do not differ in head size. Males and females are sexually dimorphic in head shape even in neonates, suggesting that this differentiation is prenatal. Differences in head shape may be associated with trophic segregation, allowing females to feed on larger prey than males. Body size dimorphism progressively increases throughout the ontogenetic stages, which is possibly related to the late sexual maturation of females and/or different growth rates between the sexes. We also found that males and females shows some sex-specific patterns towards static and ontogenetic allometry, with males showing stronger predictive response on static allometry than females, whereas females have ontogenetic allometry, but males do not. Additionally, the allometric slopes in A. reticulatus between sexes converge by presenting similar shapes as head size increases, an expected result for sexes with similar lifestyles. Further investigation on some physiological and natural history aspects in Atractus will be particularly useful for a better understanding of the significance of the morphological differences found in this study.

Descrição de uma nova espécie de serpente do gênero Tantilla Girard in Baird and Girard, 1853 (Colubridae: Colubrinae) do sul do Brasil

The genus Tantilla comprises 66 species, being one of the most diverse genera of snakes of the New World. In Brazil, there are two recognized species, T. boipiranga and T. melanocephala. The latter has the largest geographical distribution occurring from Guatemala to northern Argentina and Uruguay, as well as the islands of Trinidad and Tobago, Mustique Island, and the Islands of Saint Vincent Grenadines and Granada. T. melanocephala still presents a high degree of variation in coloration and general morphometry of the body. Therefore, a taxonomic revision of the T. melanocephala complex was carried out, with follicular characters, coloration and general morphometry of the 169 specimens being analyzed. A population of Tantilla was found, which is distributed through the southern Brazil, presented here as a new species. T. sp. n. is immediately distinguishable from the T. melanocephala complex by the presence of a blackish and broadened cephalic hood, covering a large part of the dorsum of the head and extending continuously to the inner scales; and presence of a longitudinal, blackened and diffuse paraventral band, later denser in the trunk. Although T. sp. n. is recognizable, there are populations along the distribution of T. melanocephala that, even though they have distinct colorations, are difficult to distinguish because there is a great overlap of meristic characters, which may mean the existence of cryptic diversity within this taxon. Finally, studies combining morphological and molecular evidences should be developed in order to test the hypothesis of cryptic diversity and elucidate the taxonomic relationships between the possible species of this complex.

O gênero Tantilla compreende 66 espécies, sendo um dos gêneros mais diversos de serpentes do Novo Mundo. No Brasil, há duas espécies reconhecidas, T. boipiranga e T. melanocephala. A última possui a maior distribuição geográfica ocorrendo desde a Guatemala, até o norte da Argentina e Uruguai, além das ilhas de Trinidad e Tobago, Ilha Mustique, e Ilhas de São Vicente Granadinas e Granada. T. melanocephala ainda apresenta alto grau de variação na coloração e morfometria geral do corpo. Diante disso, conduziu-se uma revisão taxonômica do complexo T. melanocephala, analisando-se caracteres de folidose, coloração e morfometria geral do corpo de 169 espécimes e descobriu-se uma população de Tantilla, que se distribui pelas áreas de campo do sul do Brasil, apresentada aqui como uma nova espécie. T. sp. n. é imediatamente distinguível do complexo T. melanocephala pela presença de capuz cefálico enegrecido e amplo, cobrindo grande parte do dorso da cabeça e estendendo-se continuamente até as escamas internasais; e presença de faixa paraventral longitudinal, enegrecida e difusa, mais adensada posteriormente no tronco. Embora T. sp. n. seja reconhecível, há populações ao longo da distribuição de T. melanocephala que, mesmo apresentando colorações distintas, são difíceis de distinguir porque há grande sobreposição de caracteres merísticos, o que pode significar a existência de diversidade críptica dentro desse táxon. Finalmente, estudos combinando evidências morfológicas e moleculares devem ser desenvolvidos, afim de testar a hipótese de diversidade críptica e elucidar as relações taxonômicas entre as possíveis espécies deste complexo.

Description of a second known Liotyphlops caissara specimen (Serpentes: Anomalepididae)

We recorded a second specimen of the poorly known insular blind snake Liotyphlops caissara. This new specimen expands the morphological variation of the number of dorsal scales in the genus Liotyphlops to 296 (vs. 304 in L. wilderi) and, considering the fact that the holotype of this species was destroyed, the present specimen represents the only available L. caissara individual in zoological collections. Also, this new record constitutes the first out of type locality and expands the distribution of the species in about 40 km to the northeastern. According to IUCN criteria (B1a, b [iii]), we suggest that L. caissara be included in the "Endangered" category, since it occurs in only two insular locations and exhibits an occurrence extension of <5,000 km² (about 355 km2).

Herpetofauna of five "Brejos de Altitude" of the interior of the state of Pernambuco, Northeastern Brazil

Brejos de altitude are found at high altitudes, generally over 600 meters above sea level, in mountainous and plateau regions throughout the Brazilian Northeast. These relict altitudinal forests display unique biota evolutionary characteristics, due to, mainly, the geological time they have spent isolated, where they serve as islands for biological specialization, with many registered endemisms. Studies that provide basic data on herpetofauna are important to understand the structure and composition of these communities. In this context, the present study aimed to compile an inventory of the herpetofauna of five brejos de altitude in the state of Pernambuco, Brazil, and compare its snake taxocenosis with that of other Caatinga localities in Northeastern Brazil. The areas were inventoried through different time, sampling and methodologies number of people and the use or not of traps. Literature data and scientific collections were used to complement the species list. A total of 88 species were recorded in all five study areas,: 32 amphibians (two orders, 8 families and 15 genera) and 56 reptiles (2 orders, 18 families and 44 genera). Four species of lizards found in the present study are endangered, and one tortoise and snake species are data deficient (DD).

Description of a second known Liotyphlops caissara specimen (Serpentes: Anomalepididae)

We recorded a second specimen of the poorly known insular blind snake Liotyphlops caissara. This new specimen expands the morphological variation of the number of dorsal scales in the genus Liotyphlops to 296 (vs. 304 in L. wilderi) and, considering the fact that the holotype of this species was destroyed, the present specimen represents the only available L. caissara individual in zoological collections. Also, this new record constitutes the first out of type locality and expands the distribution of the species in about 40 km to the northeastern. According to IUCN criteria (B1a, b [iii]), we suggest that L. caissara be included in the "Endangered" category, since it occurs in only two insular locations and exhibits an occurrence extension of <5,000 km² (about 355 km2).

Herpetofauna of five "Brejos de Altitude" of the interior of the state of Pernambuco, Northeastern Brazil

Brejos de altitude are found at high altitudes, generally over 600 meters above sea level, in mountainous and plateau regions throughout the Brazilian Northeast. These relict altitudinal forests display unique biota evolutionary characteristics, due to, mainly, the geological time they have spent isolated, where they serve as islands for biological specialization, with many registered endemisms. Studies that provide basic data on herpetofauna are important to understand the structure and composition of these communities. In this context, the present study aimed to compile an inventory of the herpetofauna of five brejos de altitude in the state of Pernambuco, Brazil, and compare its snake taxocenosis with that of other Caatinga localities in Northeastern Brazil. The areas were inventoried through different time, sampling and methodologies number of people and the use or not of traps. Literature data and scientific collections were used to complement the species list. A total of 88 species were recorded in all five study areas,: 32 amphibians (two orders, 8 families and 15 genera) and 56 reptiles (2 orders, 18 families and 44 genera). Four species of lizards found in the present study are endangered, and one tortoise and snake species are data deficient (DD).

New records of the rare Troschel’s Pampas snake, Phimophis guianensis (Serpentes: Dipsadidae) in Brazil

The Troschel’s Pampas Snake, Phimophis guianensis (Troschel, 1848), is widely distributed in Amazonian Savannas at northern South America and a small portion of southern Central America, being recorded to Brazil based on three historical records, that ranged from 1997 to 2002, in Amapá and Pará states. In this study, we revise all known records of P. guianensis, providing an updated distribution map, and the first record to Roraima state.

New records of the rare Troschel’s Pampas Snake, Phimophis guianensis (Serpentes: Dipsadidae) in Brazil

The Troschel’s Pampas Snake, Phimophis guianensis (Troschel, 1848), is widely distributed in Amazonian Savannas at northern South America and a small portion of southern Central America, being recorded to Brazil based on three historical records, that ranged from 1997 to 2002, in Amapá and Pará states. In this study, we revise all known records of P. guianensis, providing an updated distribution map, and the first record to Roraima state.