Francisco Kolenc

Chromosomal Variation in the Species of the Physalaemus henselii Group (Anura: Leiuperidae)

Abstract In this work, we studied chromosome morphology, Ag-NOR, and C-banding patterns in the Neotropical leiuperid frogs that compose the Physalaemus henselii species group: Physalaemus fernandezae, Physalaemus henselii, and Physalaemus riograndensis. The chromosome diploid complement in all species was 2n  =  22 and consisted of seven large to medium and four small chromosome pairs. Chromosome fundamental number (FN) varied, because pair 11 was metacentric in P. henselii and P. riograndensis (FN  =  44) but telocentric in P. fernandezae (FN  =  42). Each species presented a single pair of Ag-NORs, which are located in the secondary constriction of pair 11 in the case of P. fernandezae, in pair 8 in P. riograndensis (as in many other Physalaemus species), and in pair 5 in P. henselii, which is a unique character state among leiuperids. There were no substantial interspecific differences in C-banding pattern, and the heterochromatic bands were mainly located in the centromeric regions of all chromosomes. Noncentromeric C-bands adjacent to NORs were detected in P. riograndensis and P. fernandezae, as already reported for other species of this genus. The karyotype of P. fernandezae was quite similar to that of species in the P. signifer group and of the leiuperid Eupemphix nattereri. Neither karyotypic data nor adult and larval morphology support the P. henselii species group as currently defined.

The Identity of Eupemphix fuscomaculatus Steindachner, 1864 (Amphibia: Anura)

Abstract Eupemphix fuscomaculatus Steindachner, 1864 was described on the basis of a single specimen collected at Caiçara, Mato Grosso, Brazil. This species, currently included in the genus Pleurodema, experienced a confusing taxonomic history and is supposedly known only from the holotype and seven specimens from Río Apa, Paraguay, collected by Alfredo Borelli in 1893–1894. Examination of Steindachners holotype and Borellis specimens revealed that they are not conspecific, E. fuscomaculatus is a junior synonym of Physalaemus biligonigerus (Cope, 1861 “1860”), and the specimens from Río Apa, Paraguay, could not be distinguished by their morphology or ploidy either from Pleurodema bibroni or P. kriegi, and are referred here as Pleurodema bibroni based on ecological considerations. Contrary to a recent proposal, the presence of vomerine teeth is not considered diagnostic for the genus Pleurodema, as they are absent in seven of the 13 species of Pleurodema examined. In addition, we propose to amend the type locality of P. biligonigerus to the surroundings of La Paz, Entre Ríos Province, Argentina.

Chytridiomycosis in frogs from Uruguay.

Amphibian chytridiomycosis caused by Batrachochytrium dendrobatidis is reported in Uruguayan native amphibians for the first time. Histological evidence of infection was observed in tadpoles of Hypsiboas pulchellus, Odontophrynus maisuma, Physalaemus henselii, and Scinax squalirostris. The effects of chytridiomycosis on these species are still unknown. However, the disease is of potential concern for the conservation of the apparently declining species P. henselii and also for O. maisuma, given its restricted distribution in habitats which are being increasingly disturbed.

Conservation status assessment of the amphibians and reptiles of Uruguay

The native species of amphibians and reptiles of Uruguay were categorized according to the IUCN Red List criteria. Out of 47 amphibian species, seven are listed as Critically Endangered (CR), five as Endangered (EN), one as Vulnerable (VU), three as Near Threatened (NT), and two as Data Deficient (DD); the remaining species are considered to be Least Concern (LC). Among the 64 species of reptiles evaluated, one is listed as Critically Endangered (CR), seven as Endangered (EN), two as Vulnerable (VU), one as Near Threatened (NT) and seven as Data Deficient (DD); the rest are considered to be Least Concern (LC). The use of these results as an additional criterion in the definition of protected areas in Uruguay will contribute towards the conservation of the aforementioned threatened species and their associated ecosystems.

The Tadpole and Karyotype of Rhinella achavali (Anura: Bufonidae)

Abstract We describe the external morphology, buccal cavity, chondrocranium, hyobranchial skeleton, and musculature of the tadpole of Rhinella achavali (Achavals Toad), along with its karyotype. Tadpoles were found in a small, permanent stream and were showing schooling behavior. The characterization of the proposed species groups within Rhinella cannot be currently improved using external larval morphology, as it seems to be much conserved within this genus. Buccal cavity morphology confirms the distinctiveness of the Rhinella veraguensis (Veragua Toad) group with respect to other known Rhinella. Musculoskeletal character states are similar among bufonids, although within this family the basal genus Melanophryniscus shows some distinctive states. The karyotype is composed of 22 bi-armed chromosomes, with secondary constrictions in pair 7, as found in the other species in the Rhinella marina (Marine Toad) group.

A Cytotaxonomic Survey of the Genus Melanophryniscus Gallardo, 1961 (Anura: Bufonidae)

Abstract We present a cytogenetic survey of the basal bufonid genus Melanophryniscus that covered 14 of the 25 species currently recognized, representing the three phenetic species groups: M. moreirae, M. stelzneri, and M. tumifrons. All species presented a diploid chromosome complement constituted by 11 bi-armed chromosome pairs (2n  =  2x  =  22; FN  =  44). Some remarkable differences were observed between species groups: chromosome pair 4 was metacentric in species of the M. tumifrons group (also with a distinctive C-positive block) but submetacentric in the M. stelzneri group and M. sanmartini (M. moreirae group); pair 5 was submetacentric in M. sanmartini and metacentric in the rest. Chromosome secondary constrictions and silver-stained nucleolar organizer regions were located either in pair 5, 7, or 8 in the M. tumifrons group, M. sanmartini and M. krauczuki (M. stelzneri group), and M. stelzneri group, respectively; and pair 7 was relatively larger in M. sanmartini and M. krauczuki. Studied cytogenetic characters support the M. tumifrons group and suggest a close relationship between M. krauczuki and M. sanmartini. These results call for a reassessment of species relations within Melanophryniscus under an inclusive phylogenetic study.

Amphibia and Reptilia, Quebrada de los Cuervos, Departamento de Treinta y Tres, Uruguay

We present an annotated list of the herpetofauna at the Protected Area Quebrada de los Cuervos, Departamento de Treinta y Tres, Uruguay. We recorded 24 species of amphibians and 29 of reptiles, accounting for near half of the species already reported from Uruguay. New records of Dendropsophus minutus (Hylidae) and Liophis almadensis (Colubridae) are presented, being the southernmost known for these species. Additionally, Melanophryniscus sanmartini (Bufonidae), Anisolepis undulatus (Polychridae), Crotalus durissus terrificus (Viperidae) and Xenodon histricus (Colubridae) are cited for the first time for the Departamento de Treinta y Tres.

Dermocystid-Chytrid Coinfection in the Neotropical Frog Hypsiboas pulchellus (Anura: Hylidae)

Abstract We present gross and histologic evidence of coinfection in amphibians by fungal-like parasites of the order Dermocystida (Amphibiocystidium sp.) and the fungus Batrachochytrium dendrobatidis. The condition was observed in frogs Hypsiboas pulchellus (Hylidae) from Uruguay in 2009 to 2012. This report is the first of dermocystids in Neotropical amphibians since 1940.

Structural and Heterochronic Variations During the Early Ontogeny in Toads (Anura: Bufonidae)

Abstract:  In recent decades, a renewed interest in comparative studies of embryonic ontogeny in anurans is taking place. Toad embryos are often employed as model organisms, and scarce attention has been put on interspecific variations. In this work we analyze the development of transient embryonic and larval structures in 21 species in five genera of Bufonidae. These species vary in their ovipositional mode and the type of environments where the embryos and tadpoles develop, including ponds, streams, and axils of leaves of terrestrial or epiphytic plants. Comparative anatomical studies and sequence heterochrony analyses show that primary morphological variations occur in the morphology at the tail-bud stage, the arrangement and development of the external gills, adhesive gland type and division timing, growth of the dorsal hatching gland on the head, configuration of the oral disc, emergence and development of the hind limbs, and presence of the abdominal sucker. Some of these transformations are best explained by phylogeny (e.g., early divergent taxa of bufonids have embryos with kyphotic body curvature, Type C adhesive glands, and a very small third pair of gills). Other traits might be correlated with reproductive modes (e.g., phytotelmata embryos hatch comparatively late and show an accelerated development of hind limbs). Because these actual variations are not well studied (e.g., less than the 10% of the known diversity of bufonids has been studied from this perspective), comprehensive analyses are required to interpret character evolution and the relationship with reproductive modes within the family.

Amphibian parasites of the Order Dermocystida (Ichthyosporea): current knowledge, taxonomic review and new records from Brazil

Amphibian parasites of the Order Dermocystida (Ichthyosporea) are widespread pathogens known mainly from Europe and North America, which cause primarily a disease of skin and subcutaneous tissue in their hosts. The taxonomy of these organisms has been problematic given their conserved morphology, similar clinical disease and pathology. Currently recognized taxa belong to the three closely related genera, Amphibiocystidium, Amphibiothecum, and Rhinosporidium, whereas species of Dermocystidium and Sphaerothecum destruens include fish parasites. Here, we review the taxonomy of Dermocystida based on a molecular phylogenetic analysis, principally of amphibian parasites, including DNA sequences obtained from amphibian hosts collected in the central-eastern region of South America. A new taxonomic arrangement is proposed, which includes the designation of type material for Dermocystidium pusula, synonymization of Amphibiothecum with Dermocystidium, and the restriction of Amphibiocystidium to its type species A. ranae. We also review the taxonomic status of Dermosporidium hylarum until the present work included in the synonymy of the human and animal pathogen R. seeberi, and considered herein as a valid taxon, however. In addition, a new species of Sphaerothecum parasitic to amphibians is described, being the first record of this genus in the southern hemisphere and in an amphibian host.