Selma M. Almeida-Santos

Comparison of the biological activities in venoms from three subspecies of the South American rattlesnake (Crotalus durissus terrificus, C. durissus cascavella and C. durissus collilineatus)

The subspecies of the South American rattlesnake, Crotalus durissus are classified according to their external morphological features and geographical distribution. We have determined some biological activities of C. durissus cascavella, C. durissus collilineatus and C. durissus terrificus venoms. C. durissus terrificus had a significantly higher clotting activity on bovine plasma and fibrinogen, human fibrinogen and rabbit plasma. C. durissus cascavella presented a statistically higher phospholipase A2 (PLA2) activity in regard to C. durissus collilineatus. Their myotoxic and proteolytic activity, median lethal doses, or median platelet aggregating doses (on rabbit and human platelets) could not differentiate the three subspecies examined. However, the electrophoretic profile and the dose-response curve for edematogenic activity for C.d. cascavella venom were different from the others. With regard to the inorganic element content of the venoms, higher levels of Br, Cl and Mg, and a lower level of Zn, were found in C.d. cascavella venom. Crotamine-like activity could not be detected in C.d. cascavella venom. Furthermore, equine antivenom specific for C. durissus terrificus venom cross-reacted equally with the antigens of the three venom pools by ELISA and Western blotting. These results indicate that the venoms from the three studied subspecies of C. durissus were very similar, except for minor differences in paw edema-inducing activity, electrophoretic profile, phospholipase A2 activity, crotamine-like activity and inorganic element contents of C.d. cascavella venom.

LIFE-HISTORY ADAPTATIONS TO ARBOREALITY IN SNAKES

If selective forces on locomotor ability and reproductive biology differ among habitats, we expect to see relationships between habitat, morphology, and life-history traits. Comparative (phylogenetically based) analysis of data from 12 pythonid and 12 boid snake species reveals multiple evolutionary shifts in habitat use, notably in the evolution of arboreal habits. Compared to terrestrial and aquatic taxa of the same overall body size, arboreal species have narrower and more laterally compressed bodies and relatively longer tails. Offspring sizes are not affected by arboreality, but presumably reflecting space constraints within their narrow bodies, arboreal species (1) produce smaller clutch sizes relative to maternal body length and (2) have left and right ovaries that overlap little if at all along the length of the body (i.e., the right ovary is positioned anterior to the left ovary) whereas in terrestrial snakes the two ovaries overlap along much of their length. This modification of ovarian morphology in arboreal snakes presumably reduces the degree of bodily distension during vitellogenesis and pregnancy, thus enhancing climbing ability and camouflage among the branches.

Reproductive biology of the southern Brazilian pitviper Bothrops neuwiedi pubescens (Serpentes, Viperidae)

Dissection of 286 specimens of the Bothrops neuwiedi pubescens , combined with data on captive individuals, provided information on the reproductive biology of this viperid snake from southern Brazil. Females attained larger body sizes than males, and reproduction was seasonal with mating taking place in autumn when males were more frequently encountered. Vitellogenesis occurred from summer to spring (January-September), sperm storage during autumn and winter (May-September), ovulation and fertilization in early spring (September), embryonic development during middle spring and summer (October-March), and parturition in the summer (January-March). Embryonic development was estimated to last from three to five months, a shorter time than was previously reported. The number of offspring of Bothrops neuwiedi pubescens born in one litter can vary from four to 25 ( x = 11). Fecundity is correlated with maternal body size. Neonates measure 17-25 cm SVL. Inferred growth rate of juveniles was low (10 mm/month in first year), with males attaining sexual maturity at about 16 months, but maturity is delayed in females for at least two additional years.

Herpetofauna de um remanescente de cerrado no estado de São Paulo, sudeste do Brasil

Apesar da grande extensao e biodiversidade, ainda existem lacunas amostrais no Cerrado. Este dominio fitogeografico vem sofrendo modificacoes acentuadas devido a sua conversao em pastagens e monoculturas. Nas ultimas quatro decadas ocorreu uma reducao de 88,5% das areas de Cerrado no estado de Sao Paulo. Restam menos de 0,8% da area original do Cerrado paulista, que originalmente cobria 14% da area do estado. Este estudo apresenta a composicao de especies, abundância e uso de habitat dos anfibios e repteis que ocorrem na Estacao Ecologica de Assis, um remanescente de Cerrado no estado de Sao Paulo. O inventario foi realizado entre setembro de 2007 e marco de 2008, em sete etapas de campo mensais de cinco dias cada, totalizando 35 dias de trabalho de campo. A amostragem foi realizada por meio de armadilhas de interceptacao e queda (AIQ), encontros ocasionais (EO), procura auditiva (PA) e procura visual (PV). Alem da amostragem em campo, foram incluidos na lista de especies os registros obtidos para o municipio de Assis presentes nas principais colecoes cientificas de anfibios e repteis do estado de Sao Paulo. Foram registradas 27 especies de anfibios pertencentes a 13 generos e seis familias (Bufonidae, Cycloramphidae, Hylidae, Leiuperidae, Leptodactylidae e Microhylidae) e 53 especies de repteis pertencentes a 38 generos e 13 familias (Amphisbaenidae, Anguidae, Gekkonidae, Gymnophthalmidae, Polychrotidae, Scincidae, Teiidae, Anomalepididae, Boidae, Colubridae, Dipsadidae, Elapidae e Viperidae). Este estudo e uma importante contribuicao para o conhecimento destas taxocenoses no ameacado Cerrado paulista. Nesse sentido, remanescentes como a Estacao Ecologica de Assis sao de extrema importância nao so para a conservacao da herpetofauna no estado de Sao Paulo, mas tambem para o dominio do Cerrado.

Bites by the colubrid snake Philodryas patagoniensis: A clinical and epidemiological study of 297 cases

We retrospectively analyzed 297 proven cases of Philodryas patagoniensis bites admitted to Hospital Vital Brazil (HVB), Butantan Institute, São Paulo, Brazil, between 1959 and 2008. Only cases in which the causative animal was brought and identified were included. Part of the snakes brought by the patients was still preserved in the collection maintained by the Laboratory of Herpetology. Of the 297 cases, in 199 it was possible to describe the gender of the snake, and seventy three (61.3%) of them were female. The length of snakes (snout-vent length) ranged from 160 to 1080 mm. In 117 snakes their state of preservation enabled the dissection and examination of their stomach contents. The stomach was empty in 106 snakes (89.1%). Most bites occurred in the seasons of spring and summer (n = 196, 66.0%) and during warmer periods of the day. The mean age of the victims was 24.1 +/- 15.1 years old and 206 (69.4%) patients were men. Around 92% of the patients sought medical care within 6 h after the bite. Both lower (n = 188, 63.3%) and upper limbs (n = 102, 34.3%) were most frequently bitten, especially the feet and hands (n = 205, 69.0%). The local clinical manifestations were pain (n = 151, 50.8%), transitory bleeding (n = 106, 35.7%), erythema (n = 47, 15.8%) and edema (n = 39, 13.1%). Ecchymosis was not observed. Only 7 (2.4%) patients reported systemic symptoms characterized by mild dizziness and 88 patients (29.6%) showed no evidence of envenoming. The whole blood clotting time was performed in 76 (25.6%) patients on admission and all of them had coagulable blood. Supportive treatment was offered to only 13.4% of patients, namely administration of antihistamines (n = 19, 6.4%) and analgesics (n = 12, 4.1%). Eight patients (2.7%) were mistreated with Bothrops antivenom before their admission to HVB. No sequels or relevant complications were observed in patients, and the prognostic was benign. Therefore, although P. patagoniensis accidents can cause mild local symptomatology, it is very important that health professionals know how to make the correct diagnosis to avoid unnecessary use of antivenom.

Mating and Reproductive Cycle in the Neotropical Colubrid Snake Chironius bicarinatus

ABSTRACT. n Chironius bicarinatus is a common colubrid snake, widely distributed throughout the Atlantic Forest. Field observations of copulation and combat, combined with data on preserved and captive snakes, as well as on specimens brought to Institute Butantan provided a better characterization of the reproductive cycle of this species. Chironius bicarinatus has a seasonal reproductive cycle with extended vitellogenesis and ovulation, and oviposition occurring at the onset of the rainy season (austral spring). Recruitment of newborns occurred mainly at the end of the rainy season. Clutch size ranged from five to 14 and relative clutch size ranged from 0.55 to 0.62. Copulation was observed four times, always in April (austral autumn) at the onset of vitellogenesis. These records correspond to the activity peak of males in the field. Thus, mating may occur prior to ovulation (in austral spring) indicating a dissociated reproductive pattern. We suggest that combat in November (in austral spring), recorded in a previous study, may be related to the presence of androgens in snakes during the non-mating season.

Natural History of the Vine Snake Oxybelis Fulgidus (Serpentes, Colubridae) From Brazil

ABSTRACT. n Aspects of natural history of the vine snake Oxybelis fulgidus from the northern region of Brazil were inferred based on the analysis of 106 preserved specimens (55 males and 51 females), and from a review of records in the published literature. Males mature at smaller size than females. Differences in body length and shape were also found among adult females and males: adult females are larger in mean snout-vent length and have relatively larger heads and shorter tails. Females have an extended seasonal vitellogenic cycle from April to December (mainly throughout the dry season). Oviductal eggs and egg-laying were recorded from September to December, while births occurred from January to April. Fecundity varied from four to twelve eggs or vitellogenic follicles (n = 13), and was positively correlated with female body length. Testicle volume is significantly larger from February to July (mainly in April and May; end of the rainy season), however the deferent ducts diameter do not differ significantly throughout the year. We hypothesized that both males and females may have an associated reproductive pattern, both synchronized in the end of the rainy season. Oxybelis fulgidus feeds on lizards (mainly iguanian) and passerine birds. Apparently, females feed more frequently on birds than males.ABSTRACT. Aspects of natural history of the vine snake Oxybelis fulgidus from the northern region of Brazil were inferred based on the analysis of 106 preserved specimens (55 males and 51 females), and from a review of records in the published literature. Males mature at smaller size than females. Differences in body length and shape were also found among adult females and males: adult females are larger in mean snout-vent length and have relatively larger heads and shorter tails. Females have an extended seasonal vitellogenic cycle from April to December (mainly throughout the dry season). Oviductal eggs and egg-laying were recorded from September to December, while births occurred from January to April. Fecundity varied from four to twelve eggs or vitellogenic follicles (n = 13), and was positively correlated with female body length. Testicle volume is significantly larger from February to July (mainly in April and May; end of the rainy season), however the deferent ducts diameter do not differ signific...

Sperm storage and morphofunctional bases of the female reproductive tract of the snake Philodryas patagoniensis from southeastern Brazil

Macroscopic and microscopic examination of the female reproductive tract of Philodryas patagoniensis was conducted in order to observe sperm storage structures and determine morphological changes throughout the reproductive cycle. The oviduct of P. patagoniensis is composed of the infundibulum (anterior and posterior), uterus, utero-vaginal junction, and vagina. The uterine epithelium showed constant secretory activity throughout the reproductive cycle, although increased production of secretory granules was observed in secondary vitellogenic females. Sperm storage occurs in the posterior infundibulum and utero-vaginal junction in pregnant, primary (postpartum), and secondary vitellogenic females. These data suggest that P. patagoniensis may be able to produce several clutches from a single mating. Sperm storage in the posterior infundibulum occurs in sperm receptacles, while in the utero-vaginal junction sperm is stored in crypts. Histochemical tests by periodic acid–Schiff revealed that both sperm storage sites increase the production of neutral carbohydrate-rich granules in the presence of sperm, similar to snakes from temperate regions. This is the first report of sperm storage in the posterior infundibulum of a neotropical snake.

ACTIVITY PATTERNS IN CORAL SNAKES, GENUS MICRURUS (ELAPIDAE), IN SOUTH AND SOUTHEASTERN BRAZIL

Abstract Seasonal abundance of four species of Micrurus in Southern and Southeastern Brazil was inferred from collection data for eight years at the Instituto Butantan, São Paulo, Brazil. For most species surface activity was significantly lower during drier and colder periods. Low temperature may considerably reduce snake metabolic rates and consequently constrain their activity. Year-round availability of prey may explain this activity pattern as well. Reproductive condition (duration of vitellogenesis and mating) may also influence activity patterns and explain some differences among species. One species (M. corallinus) shows vitellogenesis and mating restricted to the first half of the rainy season (spring), when activity peaked. Field data and activity patterns indicate that mating occurs from the end of the rainy season to the first half of the dry season (in autumn) in the other three species (M. altirostris, M. frontalis, M. lemniscatus), which belong to the same clade, and this sets them apart of M. corallinus. The data obtained here indicate that differential reproductive strategies occur in two distinct clades of Micrurus.

Reproductive Biology of Bothrops erythromelas from the Brazilian Caatinga

The reproductive biology of Bothrops erythromelas, a small pit viper from the Caatinga, a semiarid biome in Brazil, is described based on analysis of individuals deposited in zoological collections. Males are smaller and also attain sexual maturity at a smaller size than females. Female reproductive cycle is seasonal with an extended period of secondary vitellogenesis and births occurring in a restricted period from late spring to early summer. Sperm storage in females may probably occur in infundibular tubular glands and uterine muscular twisting (UMT), which is a polymorphic condition within B. erythromelas. Seasonal spermatogenesis in males is variable with some intraspecific variation regarding the male reproductive stage per season. Most males are reproductively active during spring/summer and reproductively quiescent during autumn/winter, although some individuals vary (e.g., show testicular spermatogenesis and active sexual segment of the kidneys (SSK) during winter). The SSK could be identified in every male. Most males showed highly hypertrophied SSK in spring/summer and moderately hypertrophied SSK in autumn/winter. The ampulla ductus deferentis was observed and histochemical reactions were conducted. We discuss the probable influence of the unique environmental conditions of the Caatinga region and phylogenetic inertia in the reproductive patterns of this snake species.