Roberta R. Pinto

Morphology and diet of two sympatric colubrid snakes, Chironius flavolineatus and Chironius quadricarinatus (Serpentes: Colubridae)

The morphometry and diet of two sympatric species of Chironius (C. flavolineatus and C. quadricarinatus) from Brazilian Cerrado are described. The two snake species differ in external morphology, as Chironius flavolineatus was the largest species (body, tail and eyes) whereas C. quadricarinatus the heaviest. Each species also showed marked sexual size dimorphism. In terms of dietary ecology, both species feed exclusively on frogs with a heavy preference for hylids and may have tendency to eat small items, as noticed in other colubrine species. These two snake species showed a brownish colour pattern and exhibited no ontogenetic variation, suggesting that juveniles and adults use similar substrates. Chironius flavolineatus and C. quadricarinatus present a semi-arboreal habit, with active foraging behaviour, feeding in the ground most of time. Chironius flavolineatus uses higher vegetation for resting and, based on morphological results, seems to be more arboreal than C. quadricarinatus.

On the Generic Identity of Siagonodon brasiliensis, with the Description of a New Leptotyphlopid from Central Brazil (Serpentes: Leptotyphlopidae)

The geographic variation and hemipenial morphology of Siagonodon brasiliensis are described based on a comprehensive sample, allowing the reappraisal of its generic identity, and the proposal of a new nomenclatural combination. We suggest that the presence of two supralabials, as mentioned in the original description of S. brasiliensis, is not a common feature for this species, occurring at low frequencies throughout its geographic distribution. Based on a diagnosis presented in a recently published paper, as well as on additional external traits and on hemipenial characters, we recognize Siagonodon brasiliensis as a species of the genus Tricheilostoma. In addition, a new species of worm snake of the genus Siagonodon is described from the savannas of the state of Tocantins, Brazil. The new species differs from other congeners by having a slightly acuminate snout in lateral and ventral views, subcircular rostral in dorsal view, and 12 scale rows around middle of tail. The diagnosis of the genus Siagonodon is revised and expanded based on direct observation of morphological characters.

Redescription of Leptotyphlops koppesi Amaral, 1954, and description of a new species of the Leptotyphlops dulcis group from Central Brazil (Serpentes: Leptotyphlopidae)

A new species of Leptotyphlops dulcis group is described from the central Brazilian Cerrado, which is diagnosed by rostral shape, general colour pattern, and number of middorsal and subcaudal scales. This taxon has been commonly misidentified as L. koppesi in some Brazilian collections and by some authors. Leptotyphlops koppesi was described from the municipality of Terenos, State of Mato Grosso do Sul, Brazil, based on a single specimen. Since its original description, only three subsequent records appear in the literature reporting additional specimens of L. koppesi. We redescrib the holotype of Leptotyphlops koppesi, defining its geographic range and diagnose this from all species of L. dulcis group. Data on morphometric and meristic variation are reported for the new species and L. koppesi as well. Comparisons are made between the new species and all other South American species of the L. dulcis group. The hemipenis of the new species has a narrow basal portion and a series of lateral flounces. This general hemipenial morphology is unique among Neotropical leptotyphlopids, otherwise known only from Atlantic Rainforest species L. salgueiroi.

Osteology and Cartilaginous Elements of Trilepida salgueiroi (Amaral, 1954) (Scolecophidia: Leptotyphlopidae)

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.

A New Blind Snake Species of the Genus Tricheilostoma from Espinhaço Range, Brazil and Taxonomic Status of Rena dimidiata (Jan, 1861) (Serpentes: Epictinae: Leptotyphlopidae)

Designation and description of a neotype and geographic variation of the blind snake Rena dimidiata are presented here on the basis of a noted sample, providing a question on its generic identity, and proposing a new taxonomic combination. Rena dimidiata is recognized here as a species of Tricheilostoma, based on putative characters published in a recent paper, additional external traits and hemipenial characters. Morphometric and meristic characters for all species of Tricheilostoma are described herein. Additionally, a new species of Tricheilostoma is described from Espinhaço Range, Brazil.

Reproductive biology of two sympatric colubrid snakes, Chironius flavolineatus and Chironius quadricarinatus, from the Brazilian Cerrado domain

The reproductive biology of Chironius flavolineatus and C. quadricarinatus from the Brazilian Cerrado domain is described, including sexual maturity, female fecundity, and reproductive cycles of males and females. Egg-laying is recorded here for the first time for C. quadricarinatus. Males of both species attain sexual maturity with a smaller snout-vent length than females. Females of C. flavolineatus have an extended reproductive cycle with egg production during the wet season, whereas males exhibit year-round sperm production. Chironius quadricarinatus has continuous reproductive cycles in both sexes. Differences in reproductive pattern between these two sympatric species are probably related to phylogenetic constraints on intrageneric lineages of Chironius.

Unveiling diversity under the skin: comparative morphology study of the cephalic glands in threadsnakes (Serpentes: Leptotyphlopidae: Epictinae)

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.

Morphological variation of Trilepida macrolepis (Peters 1857), with reappraisal of the taxonomic status of Rena affinis (Boulenger 1884) (Serpentes: Leptotyphlopidae: Epictinae)

We report on the morphological variation (meristic, morphometric, pholidosis, and color pattern characters) and sexual dimorphism of Trilepida macrolepis. We also took the opportunity to redescribe the holotype of Rena affinis in an effort to evaluate its taxonomic status. Based on the congruence of characters from external morphology, we transfer Stenostoma affine to the genus Trilepida. We also discuss the Andean specimens previously refereed to Trilepida affinis and Trilepida macrolepis and provide an identification key for the genus Trilepida.

Morphological variation in the Brazilian Radiated Swamp Turtle Acanthochelys radiolata (Mikan, 1820) (Testudines: Chelidae)

The freshwater turtle Acanthochelys radiolata (Mikan, 1820) is endemic to the Atlantic Forest domain in Brazil and few studies have been done on the morphology, geographic variation and taxonomy of this species. In this paper we record the morphological variation, as well as sexual dimorphism and ontogenetic changes in A. radiolata throughout its distribution range. We analyzed 118 morphological characters from 41 specimens, both quantitative and qualitative, and performed statistical analyses to evaluate size and shape variation within our sample. Morphological analysis revealed that A. radiolata is a polymorphic species, especially regarding color and shape. Two color patterns were recognized for the carapace and three for the plastron. Diagnostic characteristics of the species, such as the rounded tubercles on the neck and the shallow dorsal sulcus between the 2nd and 4th vertebral scutes, varied considerably. Acanthochelys radiolata also showed a high level of ontogenetic variation characterized by a change on the color pattern of plastron and limbs starting from the 4th month of life. Sexual size dimorphism was observed for the first time on nine morphometric variables and females showed larger sizes than males. Based on these results we conclude that A. radiolata represents one single polymorphic species distributed in the lowlands of the Brazilian Atlantic Forest from the state of Alagoas to the state of Rio de Janeiro and the south of Minas Gerais state.