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ABSTRACT. Physalaemus henselii (Peters, 1872) is a little known leiuperid frog that has not been studied since the 1960's. Herein, we redescribe its advertisement call, and assess the female sexual cycle and the reproductive period on the basis of the macroscopic analysis of the ovaries and field observations. The Ovarian Size Factor (OSF) was calculated. The study was made in Departamento de Rivera, northern Uruguay. The advertisement call consists of short (177 ± 21ms), multipulsed (20 ± 3 pulses/note) notes, with a note repetition rate of 1.57 ± 0.13 notes/s. Physalaemus henselii has a female sexual cycle with unimodal distribution of gravid females, which are present from February to September. The OSF and the ratio "females with mature oocytes / females without mature oocytes" reached the highest values from April to June. The number and size of oocytes were positively correlated with female size. The smallest female (SVL =18.94mm, weight =0.78g) with mature oocytes was found in July. The observed sexual cycle with a single annual reproductive period during the cold season (autumn and early winter), is an uncommon fact for anuran species in the region.

Although Physalaemus frogs are prominent members of Neotropical herpetofauna, larval stages are not known from more than half of the species in this genus. Herein, we describe the tadpole of Physalaemus henselii based on samples collected in Departamento de Rivera, northern Uruguay. General aspect and major external morphological features are similar to most of other known tadpoles of Physalaemus. Remarkable character states are a medial vent tube and the presence of dorsal and ventral gaps in the row of marginal oral papillae. Physalaemus henselii has been successively assigned to the P. cuvieri and to the P. henselii species groups, but no conclusions can be drawn in support of these associations from external larval morphology. Instead, we found that some character states may contribute to relate species, like the presence of a ventral gap in the marginal row of oral papillae which is shared by P. albonotatus, P. cuqui, P. cuvieri, P. fernandezae and P. henselii. This character state is unique among non-bufonid anurans, although it is also present in some species of the related genus Pseudopaludicola. In addition, P. albonotatus, P. cuqui and P. cuvieri tadpoles can be differentiated from P. fernandezae and P. henselii by the presence of two small ventrolateral gaps, which are absent in the latter.

Geographic distribution and conservation status of Caiman latirostris (Crocodylia, Alligatoridae) in Uruguay. Populations of Caiman latirostris are known to occur in Uruguay but their geographic distribution remains uncertain. This work presents an update of the species distribution and conservation status in Uruguay. Surveys conducted by the authors confirmed the presence of this species in the previously known distribution range of northwestern Uruguay, where it seems to be widespread and relatively abundant in contrast to earlier reports. We report new localities for C. latirostris, most relevant being those of the Cebollatí and Tacuarí Rivers, and the Pelotas, India Muerta and San Miguel stream basins, which significantly expand its distribution through important wetlands in the eastern part of the country. The overall distribution is coincident with different landscape types, where lagoons, artificial impoundments, livestock waterholes, rivers, streams, creeks and marshes are inhabited by caiman. Illegal non-commercial hunting was detected all over the country.

Chaunus dorbignyi and Chaunus fernandezae are the southernmost taxa of the Chaunus granulosus species group (formerly Bufo granulosus group). The biology of these species has been scarcely studied. In this sense, larval external morphology of Chaunus dorbignyi is described for the first time and compared with other species of the granulosus group, particularly with C. fernandezae. The tadpoles of C. dorbignyi at stages 31–35 are about 15 mm, and belong to the benthic ecomorphological guild. They have a depressed body, a slightly truncated snout, and the spiracle is placed on the posterior third of the body. The tail axis is straight, the dorsal fin begins at tail-body junction and ends broadly rounded. The vent tube is medial, it starts at midline and opens usually to the right, but in some specimens it opens to the left. The oral disc has a single row of marginal papillae, large dorsal gap, medium-sized ventral gap, and labial tooth row formula 2(2)/2. A multivariate analysis of morphometric variables provided differentiation from tadpoles of C. fernandezae, based on interorbital, eye-nostril and fronto-nasal distances, body maximum height and width, and dorsal gap length. However, the general aspect of both species is quite similar, and comparable to the tadpole of a related species, Chaunus pygmaeus. Other known tadpoles of the granulosus group are those of Chaunus granulosus beebei and Chaunus granulosus major, which differ from the above mentioned species in having a more depressed snout and body, and labial tooth row formula 2(2)/3. The observed variability in the vent tube opening of C. dorbignyi (and also in C. fernandezae) seems to depend on how the beginning of the ventral fin is folded, which is attached to the tube. This fact may have lead to different interpretations of vent tube configuration in the granulosus group, and must be taken into account in between-species comparisons.