Laura Verrastro

A NEW SPECIES OF LIOLAEMUS FROM SOUTHERN BRAZIL (IGUANIA: TROPIDURIDAE)

We describe a new species of the genus Liolaemus from Rio Grande do Sul, Brazil. The morphology of the new species, L. arambarensis sp. nov, is compared to other species of Liolaemus of the “wiegmannii” group. The new species is distinguished from others members of this group by a dorsal color pattern with a medium dorsal white stripe and two dorsolateral stripes, two rows of juxtaposed brown marks resembling triangles, delimited by a white bar; nasal scales oriented dorsally; a complete row of dorsally oriented lorilabial scales between the subocular and supralabial scales; a moderate number of scales around the mid-body; flat temporal scales; flat head scales; and a transversely divided frontal. Liolaemus arambarensis sp. nov. is omnivorous, oviparous, and exhibits sexual dimorphism in color and size. Resumo Uma nova espécie do gênero Liolaemus do Rio Grande do Sul, Brazil é descrita neste trabalho. A morfologia da nova espécie, L. arambarensis sp. nov, é comparada às espécies de Liolaemus do grupo “wiegmannii.” A nova espécie se distingue dos demais membros desse grupo pelo padrão de coloração dorsal com uma faixa branca médio dorsal e duas faixas dorsolaterais, duas fileiras justapostas de marcas marrons lembrando triângulos, limitadas por uma barra branca; escamas nasais orientadas dorsalmente; um linha completa de escamas lorilabiais entre as escamas subocular e supralabial orientada dorsalmente; um número moderado de escamas ao redor do corpo escamas temporais planas; escamas da cabeça planas; e, frontal dividida transversalmente. Liolaemus arambarensis sp. nov. é omnívoro, ovíparo e com marcante dimorfismo sexual em cor e tamanho.

The occurrence of defensive alkaloids in non-integumentary tissues of the Brazilian red-belly toad Melanophryniscus simplex (Bufonidae)

The red-belly toads (Melanophryniscus) of southern South America secrete defensive alkaloids from dermal granular glands. To date, all information on Melanophryniscus alkaloids has been obtained by extraction from either skins or whole organisms; however, in other amphibians, tetrodotoxins, samandarines, and bufadienolides have been detected in both skin and other organs, which raise the possibility that lipophilic alkaloids may occur in non-integumentary tissues in Melanophryniscus as well. To test this hypothesis, we studied the distribution of alkaloids in the skin, skeletal muscle, liver, and mature oocytes of the red-belly toad M. simplex from three localities in southern Brazil. Gas chromatography and mass spectrometry of skin extracts from 11 individuals of M. simplex resulted in the detection of 47 alkaloids (including isomers), 9 unclassified and 38 from 12 known structural classes. Each alkaloid that was present in the skin of an individual was also present in the same relative proportion in that individual’s skeletal muscle, liver, and oocytes. The most abundant and widely distributed alkaloids were the pumiliotoxins 251D, 267C, and 323A, 5,8-disubstituted indolizidines 207A and 223D, 5,6,8-trisubstituted indolizidine 231B, 3,5-disubstituted pyrrolizidines cis-223B and cis- and trans-251K, and izidine 211C. We report the first record of piperidines in Melanophryniscus, bringing the total number of alkaloid classes detected in this genus to 16. Alkaloid composition differed significantly among the three study sites. The functional significance of defensive chemicals in non-integumentary tissues is unknown.

Analysis of Growth in a Population of Liolaemus occipitalis Boul. 1885, from the Coastal Sand-dunes of Tramandai, RS, Brazil (Reptilia, Tropiduridae)

The growth of the species Liolaemus occipitalis was analysed in a coastal population of Rio Grande do Sul. The comparative analysis of growth rate was carried out between 32 males and 45 females throughout one year. Taking into consideration the well‐defined seasonality of this temperate zone, the ontogenetic development (size and weight) was observed. Sexual dimorphism was evident from the viewpoint of size, females always being smaller. The annual growth curve of the individuals from this population is similar to that of lizards from temperate zones, with maximum rates in spring and growth rates close to zero in winter. Among the species of Liolaemus studied so far, L. occipitalis proves to be one of the smallest.

Annual activity of the lizard Liolaemus occipitalis (Squamata, Liolaemidae) in the coastal sand dunes of southern Brazil

The activity pattern of the small sand lizard, Liolaemus occipitalis Boulenger, 1885, was investigated in the coastal sand dunes at Quintao beach (Palmares do Sul, southern, Brazil), between September 1998 and August 1999. The results showed that L. occipitalis is active all along the year, but with variations in its daily and seasonal activity patterns associated to climatic changes in the habitat. Lizard activity pattern was distributed as follows: under the sand, burrowed (73%), under vegetation (14%), dislocation (7%) and basking (6%). Mean habitat temperatures (air and substrate) were significantly different. The results indicate that L. occipitalis is a thigmothermic and heliothermic species that regulates its body temperature through behavioral mechanisms, and that thermoregulation is mainly associated with substrate.

Supernumerary epidermal shields and carapace variation in Orbigny's slider turtles, Trachemys dorbigni (Testudines, Emydidae)

The epidermal plates of the carapace and plastron of 51 adults (38 females and 13 males), 07 immature individuals, and 46 hatchlings of the freshwater turtle Trachemys dorbigni (Duremil & Bibron, 1835), originated from the delta of Rio Jacui region, Rio Grande do Sul state, Brazil, were examined. The results showed that 7.7% of males, 10.52% of females, 14.28% of immature individuals, and 6.52% of the hatchlings presented a kind of anomaly on the shell, as well as a presence of supernumerary epidermal shields. Although the modification in the number of epidermal shields presents a high frequency in Testudines, these are the first descriptions of the variation in the pattern of carapacial scutation in eleven individuals from a population of T. dorbigni. The association of several environmental factors acting on the embryonic development of the individual may be responsible for the alteration of the pattern of carapacial scutation in this species.

Ciclo reprodutivo de machos de Liolaemus occipitalis Boulenger (Sauria, Tropiduridae)

The aim of this work is to describe the reprodutive cycle of the males of L. occipitalis from the coastal sand-dunes of Rio Grande do Sul State, Brazil. It was carried out between April/86 and March/88, at Jardim Atlântico Beach, Tramandai, Rio Grande do Sul. These lizards showed reprodutive activity between September and December, with a retreat period during January and February. The seasonality of the reprodutive cycle became fully evident by the monthly variation of the testicular mass, showing an inverse relation with the temperature along the year.

Ritmo de atividade de Liolaemus Occipitalis boulenger (Sauria, Tropiduridae) na praia de Quintão, Rio Grande do Sul, Brasil

The activity rhythm of the lizard Liolaemus occipitalis Boulenger, 1885 was studied during the summer of 93 at the sand dunes of the Quintao beach, from 06:00-18:00h. During sunny days this lizard exhibited two peaks of activity (1000-1200h and 1400-1600h), and in the cloudy days it exhibited one peak of activity (1200-1400h). The number of burrows was observed and the different soil temperatures was compared with the rhythm of activity exhibited by the lizards. Rhythm of activity is determined mainly by soil surface temperatures.

Observações sobre o comportamento de Liolaemus occipitalis em cativeiro (Sauria, Tropiduridae)

Liolaemus occipitalis (Boulenger, 1885) is an abundant lizard lbundalong lhe coastal dunes of Rio Grande do Sul, Brazil. Fourteen individuais were manually captured in the dunes of Quintao beach (Palmares do Sul, Rio Grande do Sul) and studied in captivity from 23/VII/92 to 30/VII/93. They were kept in a terrarium with sand substrate and vegetation collected in their habitat. Snout-vent length (SVL) and wcighted were measured weekly. They received Tenebrio molitor (Linnaeus, 1758) worms as food; water was abundant. Combats between males for food and territory, and other behavioral displays were observed, like copulation and nesting behaviors. Growth curves for each lizard were analyzed.

The Influences of Habitat on Body Temperature Control in a Southern Population of Liolaemus occipitalis (Boulenger, 1885) in Brazil

Abstract. This study aimed to estimate the degree of body temperature control of the sand dune lizard Liolaemus occipitalis in the subtemperate climate region of southern Brazil. The data suggest more accurate thermoregulation in males than females. Sand substrate appears to be more important than air in serving as a heat source for the lizards. The high conductivity of sand might minimize the effects of the relatively low average air temperatures in southern Brazil. Nevertheless, the mean body temperature of L. occipitalis from southern Brazil was lower than that recorded in northern populations of L. occipitalis and other Liolaemus species in southern latitudes of South America. This suggests that maintenance of body temperature might be the limiting factor for the expansion of the southern limit of the species distribution.

Descrição do esqueleto axial de Liolaemus arambarensis Verrastro, Veronese, Bujes & Dias Filho (Iguania, Liolaemidae): regiões pré-sacral e sacral

Liolaemus arambarensis Verrastro, Veronese, Bujes & Dias Filho , 2003 (Iguania: Liolaemidae) is a small sand lizard that inhabits restingas in the Patos Lagoon, Southern Brazil. The description of the skeleton in this species could give some insights about the phylogenetic relationships with other species of the genus. With the main goal of describing the pre-sacral and sacral regions of the axial skeleton of L . arambarensis , a total of seven individuals were analyzed. It was observed that the largest axial structure is the vertebral column that is divided into four regions: cervical, dorsal, sacral and caudal. The cervical region presents eight vertebra and the ribs could be observed after the fourth vertebrae. The dorsal region is divided in: thoracic with five vertebra carrying five ribs joined to stern, and post-thoracic with 11 vertebra and free ribs. The sacral region has two fused vertebra that present transversal processes highly expanded laterally. The stern of L . arambarensis is composed by a calcified cartilaginous plate that communicates with the thoracic region of the vertebral column, and with the scapular waist. Regarding the described previously, L . arambarensis presents the patterns of axial skeleton described for the species in its family and genus.