A cladistic analysis of Scinax (Anura: Hylidae)

The hylid frog genus Scinax ranges from southern Mexico to eastern Argentina. The 84 recognized species are currently arranged in five groups: the Scinax rubra , Scinax rostrata , Scinax catharinae , Scinax staufferi , and Scinax perpusilla species groups. Although a few species groups are distinctive, compelling evidence of monophyly is lacking for three groups, and their interrelationships remain virtually unknown. With the objective of testing the monophyly of the species groups and exploring their interrelationships, a cladistic analysis was performed, employing 86 characters from osteology, myology, adult and larval external morphology, reproductive biology, and karyotypes taken from 36 representative species of the five species groups plus eight outgroup taxa. The analysis of the resulting data matrix shows moderately well-supported (as assessed through Bremer support and parsimony jackknifing) S. catharinae and S. rostrata species groups. The S. staufferi species group is polyphyletic, as currently composed, given that some of its species are nested within the S. catharinae species group. The only representative of the S. perpusilla species group is the sister species of the S. catharinae species group. Although weakly supported, the representatives of the S. rostrata and S. staufferi species groups are nested, separately, within the S. rubra species group. In order to have a taxonomy consistent with these results, it is proposed not to recognize the S. rubra group but to recognize a more inclusive rubra clade that includes all studied exemplars of the former S. rubra group, plus some of the S. staufferi group and all of the S. rostrata group. Similarly, a catharinae clade is recognized, within which all studied exemplars of the S. catharina e group (that now includes Scinax berthae and Scinax agilis ) and the one studied representative of the S. perpusilla group are included.     

Dendropsophus minutus (Hylidae) tadpole evaluation of predation risk by fishing spiders (Thaumasia sp.: Pisauridae) is modulated by size and social environment

Journal of Ethology - Predator–prey interactions can cross ecosystem boundaries and the outcome of these interactions is seen in prey defensive behavior. We aimed to test how the presence of...     

The phylogeny of Dendropsophini (Anura: Hylidae: Hylinae)

The relationships of the hyline tribe Dendropsophini remain poorly studied, with most published analyses dealing with few of the species groups of Dendropsophus. In order to test the monophyly of Dendropsophini, its genera, and the species groups currently recognized in Dendropsophus, we performed a total evidence phylogenetic analysis. The molecular dataset included sequences of three mitochondrial and five nuclear genes from 210 terminals, including 12 outgroup species, the two species of Xenohyla, and 93 of the 108 recognized species of Dendropsophus. The phenomic dataset includes 46 terminals, one per species (34 Dendropsophus, one Xenohyla, and 11 outgroup species). Our results corroborate the monophyly of Dendropsophini and the reciprocal monophyly of Dendropsophus and Xenohyla. Some species groups of Dendropsophus are paraphyletic (the D. microcephalus, D. minimus, and D. parviceps groups, and the D. rubicundulus clade). On the basis of our results, we recognize nine species groups; for three of them (D. leucophyllatus, D. microcephalus, and D. parviceps groups) we recognize some nominal clades to highlight specific morphology or relationships and facilitate species taxonomy. We further discuss the evolution of oviposition site selection, where our results show multiple instances of independent evolution of terrestrial egg clutches during the evolutionary history of Dendropsophus.     

New conditions and intraspecific variation of some muscles of hands and feet of Dendropsophus labialis (Peters, 1863) (Anura,Hylidae)

Systematics of frogs have been based on osteological and molecular characters; however, the morphology of the muscles of hands and feet has proven to be an important complement to these studies, but it has not been sufficiently studied. This study presents undescribed conditions based on the origin, insertion or arrangement of 18 muscles of hands and feet of Dendropsophus labialis, and intraspecific variation. Muscles of four specimens (two males and two females) were examined to observe both sides of each specimen determining new conditions, and comparing them with documented species of Dendropsophus. Four intraspecific variant categories were established: Minor, unique, explosive and mimicking. Mainly mimicking, explosive and unique variations were found. Our results show the need to expand intraspecific studies in more species of Dendropsophus and to assess its value in the phylogeny of the genus. The family Hylidae may be identifiable based upon the combination of character states of some of these muscles: the m. flexor indicis superficialis proprius and the group of tendines superficialis digitorum of hands and foot, the m. extensor brevis superficialis Digiti III of the hand, the m. extensor brevis superficialis Digiti IV in hands and the mm. extensores breves profundi Digiti III in hands.     

Meiotic chromosomes of the tree frog Smilisca baudinii (Anura: Hylidae)

The Mexican tree frog Smilisca baudinii, is a very common frog in Central America. In spite their importance to keep the ecological equilibrium of the rainforest, its biology and genetics are poorly known. In order to contribute with its biological knowledge, we described the typical meiotic karyotype based in standard cytogenetic protocols to specimens collected in Tabasco, Mexico. The study was centered in the analysis of 131 chromosome spreads at meiotic stage from two adults of the species (one female and one male). The metaphase analysis allowed the establishment of the modal haploid number of 1n = 12 bivalent chromosomes. The chromosomic formulae from the haploid bivalent karyotype was integrated by 12 biarmed chromosomes characterized by twelve pairs of metacentric-submetacentric (msm) chromosomes. The meiotic counting gives the idea that diploid chromosome number is integrated by a complement of 2n = 24 biarmed chromosomes. The presence of sex chromosomes from female and male meiotic spreads was not observed. Current results suggest that S. baudinii chromosome structure is well shared among Hylidae family and "B" chromosomes are particular structures that have very important evolutionary consequences in species diversification.     

Observations on the polyphyodont dentition of Hemiphractus proboscideus (Anura: Hylidae)

In Hemiphractus fang–like teeth are ankylosed to the premaxilla, maxilla and prevomer, and bony odontoids are found on the dentary, angular and palatine bones. The odontoids are small, but a larger pair at the front of the lower jaw project upwards and backwards into the mouth and fit into a diastema between the anterior premaxillary teeth when the mouth is closed.
The teeth are unipartite and monocuspid, and each consists of a strongly recurved and elongated cone of orthodentine, capped at the tip by a thin layer of enamel. The inner circumpulpal layer of the dentine is tubular, but no tubules are present in the outer pallial layer. During tooth development, dentine is formed before the enamel matrix is produced, and the tooth germs lie horizontally beneath the ventral surface of each dentigerous bone. On eruption, the tooth germs migrate horizontally and become ankylosed to the outer edge of the jaw bone by a layer of cellular cementum.
During tooth replacement, the vast majority of the dentine of each tooth, and the cementum at the tooth base, are resorbed by osteoclasts. It is not clear whether the tips of the teeth are shed or not.     

The tadpole of Scinax aromothyella (Anura: Hylidae) from Uruguay

We describe the tadpole of Scinax aromothyella from the surroundings of Quebrada de los Cuervos, Departamento de Treinta y Tres, Uruguay. It shares with other larvae of the Scinax catharinae clade the slightly depressed body, a dextral vent tube that reaches the free margin of the ventral fin, and the oral disc with a dorsal gap in the marginal row of papillae and with a concave posterior edge. It is most similar to the tadpole of Scinax berthae, from which it differs in the larger total length of S. aromothyella.

Describimos la larva de Scinax aromothyella de los alrededores de la Quebrada de los Cuervos, Departamento de Treinta y Tres, Uruguay. Comparte con las larvas de otras especies del clado de Scinax catharinae el tener el cuerpo levemente deprimido, el tubo proctodeal dextro que alcanza el borde libre de la aleta ventral, y el disco oral con un claro rostral en la hilera de papilas marginales y con su borde posterior cóncavo. Es muy parecida a la larva de Scinax berthae, de la que difiere en la mayor longitud total de S. aromothyella.     

The submandibular musculature of phyllomedusinae (Anura: Hylidae): A reappraisal

The submandibular musculature of 37 species of the five currently recognized genera of the subfamily Phyllomedusinae (Anura: Hylidae) is described; observations are made on the variation and ontogeny of these muscles. Supplementary apical elements of the m. intermandibularis occur in all phyllomedusines studied, in addition to the supplementary posterolateral elements previously reported. Our observations are discussed in the context of 1) the proposed homology between supplementary apical and posterolateral elements; 2) the homology with the apical elements reported for Pelodryadinae (sister taxon of Phyllomedusinae); and 3) the implications for our understanding of the relationships between Phyllomedusinae and Pelodryadinae. Anatomical differences between the apical and posterolateral elements and their co‐occurrence in phyllomedusines indicate that these supplementary elements are not homologous. Despite differences between phyllomedusines and pelodryadines in the adhesion of supplementary fibers to the principal element of the m. intermandibularis and the occurrence of a broad aponeurosis or a medial raphe, the extensive morphological and developmental resemblances of the apical elements indicate that these structures are homologous, and that the presence of apical elements is a synapomorphy of Phyllomedusinae + Pelodryadinae. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.     

Muscle development in the abdominal region of Larval Hylidae (Amphibia: Anura)

Larval muscle development in the abdominal region of five species of hylid frogs (Scinax nasicum, S. fuscovarium, Hyla andina, Phyllomedusa boliviana, Gastrotheca gracilis) was studied using differential staining techniques. These five species represent three major hylid subfamilies. The development of the main abdominal muscles, the rectus abdominis, the two lateral muscles (obliquus externus and transversus), and the lateral pectoralis abdominalis is described. The number of myotomes of the rectus abdominis varies between five and six, and the abdominal muscles associated with the rectus abdominis (obliquus externus, pectoralis abdominalis, and rectus cervicis) vary interspecifically in time of appearance and configuration. The presence of gaps in the configuration of the rectus abdominis has been related to the lotic habits of the larvae. However, our observations indicate the presence of such gaps in larvae that inhabit lentic environments as well. These results suggest that the presence of these gaps is unrelated to larval habitat. There are relatively small differences in muscle morphology among these closely related species, which apparently cannot be explained by morphological adaptations related to their ecology. In the species studied, the number of elements that form the abdominal musculature in larvae is equal to that observed in adults. Likewise, the general morphology of the muscles is ontogenetically conserved. This suggests that both the axial skeleton and musculature are more ontogenetically conserved in relation to the substantial changes that are observed in the skull and head muscles of developing anurans. J. Morphol. 241:275–282, 1999. © 1999 Wiley‐Liss, Inc.     

Structural diversity of nuptial pads in Phyllomedusinae (Amphibia: Anura: Hylidae)

We studied the morphological variation of the nuptial pads using light microscopy and scanning electron microscopy (SEM) in 26 species of phyllomedusines (Anura: Hylidae), representing the five currently recognized genera. All phyllomedusines have single nuptial pads with dark colored epidermal projections (EPs). Spine‐shaped EPs occur in Cruziohyla calcarifer, Phrynomedusa appendiculata and in one species of Phasmahyla. The other species have roundish EPs. The density of the EPs on the pad is variable. Species in the Phyllomedusa hypochondrialis Group have EPs with a density that varies between 764 ± 58/mm² and 923 ± 160/mm². In all other studied species (including the Phyllomedusa burmeisteri and Phyllomedusa perinesos groups, Phyllomedusa camba, Phyllomedusa boliviana, Phyllomedusa sauvagii, Phyllomedusa bicolor, and Phyllomedusa tomopterna) the density of EPs varies between 108 ± 20/mm² and 552 ± 97/mm². Pores were observed with SEM in C. calcarifer, Agalychnis lemur, Agalychnis moreletii, but its presence is confirmed through histological sections on several other species. Its visibility using SEM seems to be related with the level of separation between adjacent EPs. The pores in the four studied species of Agalychnis are shown with SEM and histological sections to have a characteristic epidermal rim, that is absent in the otherphyllomedusines. Unlike most previous reports on breeding glands, those of phyllomedusines are alcian blue positive, indicating the presence of acidic mucosubstances on its secretions. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc.     

A new species of Osteocephalus (Anura: Hylidae) from Guyana.

A new member of the genus Osteocephalus is described from the Pakaraima mountains of western Guyana. This species is the smallest known member of the genus and is probably closely related to O. subtilis. Both share a small size (less than 40 mm snout-vent length), large and bulgy eyes directed somewhat rostrally, green bones, smooth and brownish dorsal skin, relatively short and truncate snout, small tympanum, subgular and laterally expanded vocal sac, poorly developed subarticular and supernumerary tubercles, a supra-anal glandular ridge, and cream-white venter and subocular region. The new species can be distinguished from O. subtilis by the Buff iris (vs black), smaller overall size (32.7 vs 35.8-38.8 mm snout-vent length), relatively larger toe disks, and less developed foot webbing. The cranium of the new species is well ossified, relatively reduced in width between the orbits, without an exposed frontoparietal fontanelle and with the anterior arm of the squamosal extending to about half the distance to the maxillary. The vocal sac is subgularly poorly developed and possess lateral extensions to the area behind the jaw angles. Well developed supraocular and suprasquamosal cartilages give support to the enlarged eyes of this species.     

Morphology, histochemistry and biochemistry of the oviduct of the toad, Bufo vulgaris (Anura, Amphibia), during the annual reproductive cycle.

On the basis of histological and histochemical characteristics the oviduct of adult Bufo vulgaris can be separated into six zones. These characteristics include mainly the relative abundance of secretory and ciliated epithelial cells, mucosal foldings, tubular glands and the staining properties of the secretory elements. The VI zone (uterine segment) is totally deprived of tubular glands and is prodoundly rich in epithelial secretory cells. These cells and the tubular glands, when well-developed, are rich in neutral and acid mucins in the preovulatory phase, whereas this content is greatly diminished after ovulation. Similarly, the weight and the length of the oviduct displays a marked seasonal pattern. The same is observed for its protein content and acid and alkaline phosphatases. These parameters show the highest values in the preovulatory period and lowest after ovulation. The toad oviduct also displays marked hydroxysteroid dehydrogenase activity along the mucosal epithelium. Its functional significance remains a matter of debate, however. A marked parallelism between the present data and those obtained by others in other amphibians indicates the existence of a common pattern of seasonal modifications correlated mainly with the release of the eggs and the formation of their multi-layered coat.     

The hyolaryngeal apparatus of three species of Scinax (Scinaxinae: Hylidae: Anura) and comparison with other Hylidae species

The hyolaryngeal apparatus includes the arytenoid, cricoid and hyoid cartilages, and varied sizes and shapes can be distinguished between species. Although the larynx is an important morphological structure for sound production in frogs, few studies describe the structures and processes of its parts in hylids. We studied the hyolaryngeal anatomy of both males and females of Scinax ruber (Laurenti, 1768), using clearing and double staining methods, comparing it with that of Scinax wandae (Pyburn and Fouquette, 1971), Scinax kennedyi (Pyburn, 1973) and other hylid species. We found that S. ruber has the largest arytenoid cartilage of any species of the subfamily Scinaxinae studied to date. We described both the laryngeal differences among three Scinax species and the interspecific variability in the shapes of the projections of the arytenoid in the males of these species. The taxonomic characters (presence/absence of processes of the cartilage of Santorini, oesophageal process or bronchial processes) described here can play a key role in differentiating these species from Scinax species and from other species. In addition, we want to contribute to the natural history and comparison of the larynges in Scinax and within the genus and the Hylidae.     

Vocalizations of Hypsiboas goianus (Lutz, 1968) (Anura: Hylidae) in Central Brazil

Environmental and morphological factors and social context influence the vocalizations of anuran species. Herein, we observed the acoustic behavior of Hypsiboas goianus males from Central Brazil and analyzed the following calls: advertisement, short aggressive and long aggressive. The acoustic parameters of advertisement calls were not correlated with air temperature, mass or snout–vent length; however, the acoustic parameters of short aggressive calls were influenced by these variables. The temporal parameters of advertisement and short aggressive calls were classified as dynamic properties, while the dominant frequency was considered a static property. Dominant frequency is the most important variable to discriminate calls among individuals.     

Phylogenetic relationships and biodiversity in Hylids (Anura: Hylidae) from French Guiana

We evaluated two biodiversity criteria, higher taxonomic diversity and phylogenetic diversity in French Guiana. For this, we used a recent assessment of the knowledge accumulated since 30 years of study on the amphibian species currently known in French Guiana. We focused on two well-represented genera, Hyla and Scinax, belonging to the subfamily Hylinae. We used partial sequences of two mitochondrial genes (16S rDNA and 12S rDNA, 813 bp) and two nuclear genes (tyrosinase and 18S rRNA, 1590 bp) covering a total of 2403 bp. According to the high bootstrap support in phylogenetic analysis of the complete dataset, the genus Scinax is a homophyletic clade formed by two species groups (rubra and rostrata) in French Guiana. The genus Hyla was confirmed to be a paraphyletic group formed by two species groups as well (30 chromosomes and the 'gladiator frogs'). We confirmed that these genera should be taxonomically reconsidered. Moreover, at the genus, subfamily and family levels, the use of only morphological characters or only molecular DNA markers would hamper estimations of biodiversity. Thus, we strongly advise the combined use of both morphology and molecular data (nuclear and mitochondrial markers).     

Conserved karyotypes in the Hyla pulchella species group (Anura, Hylidae)

Cytogenetic analyses were done on specimens of Hyla marginata and on three populations of H. semiguttata differing in morphology and in the physical parameters of their advertisement call, as well as in individuals of Hyla sp. (aff. semiguttata). All specimens had 2n=24 chromosomes with a morphology very similar to that of other 24-chromosome Hyla species. Hyla semiguttata and H. marginata showed the same C-banding pattern but were distinguished by the location of the NOR on pair 1 in H. semiguttata (in the three populations) and Hyla sp. (aff. semiguttata), and on pair 10 in H. marginata. The H. semiguttata populations did not differ cytogenetically, despite variations in their morphology and advertisement calls. Similarly, H. semiguttata and H. p. joaquini studied previously had identical C-banding patterns and NOR locations, suggesting that they are very closely related.     

A total evidence analysis of the phylogeny of hatchet-faced treefrogs (Anura: Hylidae: Sphaenorhynchus)

The Neotropical hylid genus Sphaenorhynchus includes 15 species of small, greenish treefrogs widespread in the Amazon and Orinoco basins, and in the Atlantic Forest of Brazil. Although some studies have addressed the phylogenetic relationships of the genus with other hylids using a few exemplar species, its internal relationships remain poorly understood. In order to test its monophyly and the relationships among its species, we performed a total evidence phylogenetic analysis of sequences of three mitochondrial and three nuclear genes, and 193 phenotypic characters from all species of Sphaenorhynchus. Our results support the monophyly of Sphaenorhynchus with molecular and phenotypic evidence, with S. pauloalvini as the earliest diverging taxon, followed by S. carneus, as the sister taxon of all remaining species of the genus. We recognize three species groups in Sphaenorhynchus (the S. lacteus, S. planicola and S. platycephalus groups), to facilitate its taxonomic study; only three species (S. carneus, S. pauloalvini and S. prasinus) remain unassigned to any group. Sequence data were not available for only two species (S. bromelicola and S. palustris) for which we scored phenotypic data; wildcard behaviour was detected only in S. bromelicola nested inside the S. platycephalus group. On the basis of the resulting phylogenetic hypothesis, we discuss the evolution of oviposition site and a number of phenotypic characters that could be associated with heterochronic events in the evolutionary history of this group.