Marcos Di-Bernardo

Diet and Feeding Behavior of Helicops infrataeniatus (Serpentes: Colubridae: Xenodontinae) in Southern Brazil

Analysis of the gut contents of 278 specimens of Helicops infrataeniatus from the eastern Central Depression of Rio Grande do Sul state, Brazil, indicates that this species feeds on fish and frogs. Fish were found in 60.0% and amphibians in 40.0% of the specimens with identifiable stomach and/or intestine content (n = 34). Fish corresponded to 69.5% and amphibians to 30.5% of the consumed items. Representatives of seven families and 10 genera of fish, from diverse microhabitats were identified. Among the amphibians, metamorphosed leptodactylids (two species of Leptodactylus and one of Pseudopaludicola) and a hylid tadpole were found. These data and field observations indicate that the species may forage in several water strata and at waters edge, during the day and/or at night. The predator–prey size relationship is weak, but positive and significant (r 2 = 0.3228, P < 0.001), indicating that large individuals of H. infrataeniatus generally ingest larger prey items. Eighty seven percent of the prey had a total length from 5 to 15% of the snout-vent length of the snakes that ingested them. Large prey, relative to snake size, were generally swallowed headfirst, whereas relatively small prey were swallowed head or tail first. The single exception was a large elongate (ophioform) fish without spiny fins: an easily swallowable and harmless prey, that was swallowed tail-first.

Seasonal and daily activity patterns of Liophis poecilogyrus (Serpentes: Colubridae) on the north coast of Rio Grande do Sul, Brazil

The seasonal and daily activity patterns of Liophis poecilogyrus and the variation in these patterns due to sexual differences and reproductive maturity were investigated based on 174 captures of snakes on the North Coast of Rio Grande do Sul, Brazil. The seasonal activity pattern was unimodal with a higher frequency of active snakes during the hot months. The daily activity pattern was bimodal along most of the year (except during the colder months) with higher frequency of active snakes in early morning and late afternoon. During the colder months, most of the active snakes were found in the hottest periods of the day. There was no significant difference regarding activity of the total males and females, mature males and females, immature males and females and mature and immature snakes. The temperature seems to be the most important factor in determining the seasonal and daily activity patterns of this population.

New Species of Melanophryniscus (Anura: Bufonidae) from Rio Grande do Sul, Southern Brazil

Abstract A new bufonid toad is described. The species belongs to the genus Melanophryniscus, and may be the largest species in this genus. Its size and external features (pale green in dorsal surface) resemble those of Melanophryniscus cambaraensis and Melanophryniscus macrogranulosus, from which it differs by the absence of frontal swelling. At present, the new species is endemic to the southern border of the Brazilian Southern Plateau, in central Rio Grande do Sul state.

Reproduction of the water snake Helicops infrataeniatus (Colubridae) in southern Brazil

The reproductive cycle, sexual maturity, fecundity, and sexual dimorphism of Helicops infrataeniatus Jan, 1865, were inferred from the analysis of 374 preserved specimens (110 males, 140 females) from the eastern Central Depression of Rio Grande do Sul, Brazil. There was no statistical difference between the SVL of newborn males and females, but mature females attained greater length than mature males. The tail of mature individuals was proportionally longer in males than in females. Males matured at a smaller size than females. The reproductive cycle of this species was longer than what is known for oviparous colubrids from subtropical and temperate zones of Brazil. In the studied population, vitellogenesis occurred from September to February. Oviductal embryos were found from September to May. Births took place in September, January, February and March, and occurred in two peaks. Litter size ranged from 5 to 22 offspring. The differences between the number of vitellogenic follicles and embryos, and between embryos and newborns were not significant, thus practically all follicles were generally converted into embryos and embryos into newborns.

Estimating Juvenile Abundance in a Population of the Semiaquatic Caecilian, Chthonerpeton indistinctum (Amphibia: Gymnophiona: Typhlonectidae), in Southern Brazil

Abstract Chthonerpeton indistinctum is nontropical, and reports suggest a distinct breeding season, allowing the potential for estimation of reproductive success. A total of 67 juvenile (and four adult) C. indistinctum were captured over five visits to a site in Rio Grande do Sul, Brazil, during Winter 2001. All individuals were marked and released, and the seven juveniles recaptured allowed a Schnabel estimate of 161.0 (95% confidence limits 81.9–343.1), the first quantitive estimate of juvenile caecilian abundance. However, the large size range of juveniles caught suggests that growth rates of individuals are highly variable or that C. indistinctum does not have a distinct breeding period in this region.

Feeding ecology in the small neotropical amphisbaenid Amphisbaena munoai (Amphisbaenidae) in southern Brazil

We analyzed the alimentary tract of 66 specimens of Amphisbaena munoai Klappenbach, 1969 from the Serra do Sudeste, state of Rio Grande do Sul, southern Brazil. Forty specimens (60.6%) had prey items in their gut. The diet consisted mainly of small invertebrate prey, such as termites, insect larvae and ants. The most abundant prey item was termites, found in 62.5% of the non empty stomachs. The high number of individual prey items in the majority of stomachs, the small size of the regular prey items, and the absence of gut content in specimens of A. munoai kept alive for about two days, indicate that this species forages very frequently. The predominance of fossorial prey items and the occasional records of nomadic ants lead us to suggest that A. munoai usually feeds underground, and occasionally forages on the surface.

First record of Chaunus achavali (Anura, Bufonidae) from Rio Grande do Sul, Brazil, with a key for the identification of the species in the Chaunus marinus group

The bufonid toad Chaunus achavali, a recently described species known only from Uruguay, is recorded for Brazil. This species is morphologically similar to C. ictericus and C. arenarum, and several individuals were labeled in Brazilian scientific collections under these taxa. A lectotype of C. arenarum is designated. Additional field notes on C. achavali and a key for the identification of the species in the Chaunus marinus group are presented.

Diet and feeding behaviour of the Neotropical parrot snake (Leptophis ahaetulla) in northern Brazil

Specimens (289) of Leptophis ahaetulla from northern Brazil and western Maranhão were examined for the composition of stomach contents. Most prey items were tree frogs, especially those of the family Hylidae (90%). Most of the anurans identified belong to the Scinax ruber species group (27%) and Scinax sp. (25%). Prey size was significantly related to snake length but not to head length. There was no significant difference related to sex in either case. Both sexes preyed on small to medium‐sized items (3–10% of snake snout–vent length). Leptophis ahaetulla seems to manipulate captured prey before ingestion since most of the prey items (83.6%) were swallowed head‐first. Leptophis ahaetulla is primarily diurnal and semi‐arboreal, inhabits disturbed and undisturbed forest, and forages primarily on the ground and in fallen vegetation, where its prey items are likely to be found at rest. †In memoriam.

Reproductive Biology of Tantilla Melanocephala (Linnaeus, 1758) (Serpentes, Colubridae) from Eastern Amazonia, Brazil

Abstract The reproductive biology of Tantilla melanocephala was studied in eastern Amazonia, Pará, Brazil. Males and females attained sexual maturity at approximately twice the length (snout–vent length  =  SVL) of newborn snakes. Mature males had a larger tail length and more subcaudal scales than mature females, whereas females were larger (SVL) and had more ventral scales than males. Total length did not differ between mature males and females. Reproduction was not seasonal. There was no correlation between the number of vitellogenic follicles and oviductal eggs. The number of eggs was positively correlated with the female SVL. The data presented here indicate that the eastern Amazonia population differs from populations in southeastern Brazil in important morphological and reproductive aspects, including the mean number of eggs produced (mean  =  1.53), which was smaller in eastern Amazonian populations.

The Taxonomic Status of Leptodactylus geminus Barrio, 1973

The advertisement calls of Leptodactylus geminus, Leptodactylus gracilis, Leptodactylus plau- manni, and Leptodactylus fuscus are analyzed and compared with published reports. Based on calling data and examination of type material, Leptodactylus geminus is synonymized with L. plaumanni. To differentiate between the sibling species L. gracilis and L. plaumanni, fieldwork is needed, including recording of ad- vertisement calls. Reliable identification of fixed specimens is not possible based on morphology and col- oration alone. Leptodactylus plaumanni Ahl, 1936 was de- scribed from a single specimen collected in Nova Teutonia (municipality Seara, State of San- ta Catarina, southern Brazil). The holotype was originally deposited in the Deutsches Kolonial- und Ubersee-Museum Bremen and is now in the herpetological collection of the Forschung- sinstitut und Naturmuseum Senckenberg, Frankfurt (Germany). Cochran (1955), Boker- mann (1966), and Mertens (1967) treated L. plau- manni as a synonym of Leptodactylus sibilatrix, which was later considered a synonym of Lep- todactylus fuscus (Heyer, 1978). In a revision of the fuscus group, however, Heyer (1978) as- signed L. plaumanni as a synonym of Leptodac- tylus gracilis based on better matching of mor- phological characters. Heyer (1978) noted that he had been unable to examine the holotype of L. plaumanni and that this specimen could be- long to another species of the same group, namely L. geminus Barrio, 1973. The external morphology of L. geminus was described as al- most identical with that of its sibling species L. gracilis. Barrio (1973) noted only minor differ- ences in mean body length and coloration; he distinguished the new species on the basis of call characteristics. Later, Scrocchi and Lavilla (1986) suggested that the ratio of the outer metacarpal tubercle length in relation to the dis- tance from the union of fourth and fifth toes to the tip of fifth toe (Tec/Dp8) was an appropriate morphological character that could discriminate amongst both species. Cardoso (1985) collected additional material at the type locality of L. plaumanni and found a striped Leptodactylus of the fuscus group, distin-