Aparasphenodon Brunoi Research Articles

Growing towards disparity: geometric morphometrics reveals sexual and allometric differences in Aparasphenodon brunoi (Anura: Hylidae: Lophyohylinae) head shape

Sexual dimorphism and allometry feature is the main categories of intraspecific variation found in animals, and techniques such as Geometric Morphometrics are effective to investigate variations in shape. Considering that many vertebrates exhibit substantial allometry and sexual dimorphism, we test the hypotheses that (1) Aparasphenodon brunoi displays ontogenetic and static allometry; and that (2) there is sexual dimorphism in head shape in this species. We analyzed 75 specimens of A. brunoi from Parque Nacional da Restinga de Jurubatiba and found significant ontogenetic and static allometries in head shape, as well as sexual dimorphism after size correction. Regarding sexual dimorphism, females tend to have larger heads, besides slightly anteriorly positioned nostrils, smaller eyes, larger canthal ridges, narrower and longer frontoparietal ridges, and larger and laterally shifted squamosal ridges. We discuss the relevance of head morphology variation in the species, as well as the presumed consequences on the species fitness.

Almost a hundred years later, the advertisement call of Aparasphenodon brunoi Miranda-Ribeiro 1920 (Anura: Hylidae) from the Atlantic Forest.

The Neotropical genus Aparasphenodon Miranda-Ribeiro is composed of five recognized species commonly referred as "casque-headed frogs" (Frost 2018). Aparasphenodon brunoi Miranda-Ribeiro occurs in Atlantic Forest lowlands from the states of São Paulo to Bahia, Brazil (Feio et al. 1998; Mollo Neto Teixeira Jr. 2012; Ruas et al. 2013). The biology of most Aparasphenodon species is poorly known. Within the genus, until now only Aparasphenodon arapapa Pimenta, Napoli Haddad has its call formally described (Lourenço-de-Moraes et al., 2013, Forti et al., 2018, Guerra et al., 2018). Herein, we describe the advertisement call of Aparasphenodon brunoi Miranda-Ribeiro.

Ecological and reproductive aspects of Aparasphenodon brunoi (Anura: Hylidae) in an ombrophilous forest area of the Atlantic Rainforest Biome, Brazil

ABSTRACT Presented is the first information on the ecological and reproductive aspects of the treefrog, Aparasphenodon brunoi Miranda-Ribeiro, 1920, living in ombrophilous forest areas of the Atlantic Rainforest, Brazil. We recorded the species’ daily activity and over the course of a year, population density during the year, microhabitat usage, diet, and some reproductive features (quantity, diameter and mean mass of oocytes, mean reproductive effort of female). Field sampling was conducted monthly from June 2015 to July 2016. Searches for treefrogs were systematic, using visual encounter surveys along 14 plots RAPELD long term research modules established in the forest. For each captured individual, we recorded the hour, microhabitat used, and perch height. The diet of the population was ascertained based on 15 individuals collected outside the study plot areas. Treefrogs used seven different types of microhabitats in the forest but the preferred microhabitats were tree-trunks and lianas. The amount of accumulated rainfall and air temperature interacted to explain the number of A. brunoi individuals active throughout the year. The reproductive strategy for females of this comparatively large arboreal frog in the ombrophilous forest is to produce clutches with a large number (900.8 ± 358.1) of relatively small-sized eggs. We conclude that in the ombrophious forest of the Vale Natural Reserve, A. brunoi is a nocturnal arboreal treefrog active throughout the year but activity increases during the wet season as a result of increased precipitation. In the forest, treefrogs tend to perch mainly on tree-trunks and lianas about 1 m above ground, where it feeds preferably on relatively large bodied arthropod prey. When living in the ombrophilous forest of the Atlantic rainforest, A. brunoi may change some features of its ecology (e.g. marked difference in the use of bromeliads) compared to when living in restinga habitats.

Use of polyvinyl chloride pipes (PVC) as potential artificial shelters for amphibians in a coastal plain forest of southeastern Brazil

We studied the use of polyvinil chloride pipes (PVC pipes) by frogs as artificial shelters in a Coastal Plain forest in the Vale Natural Reserve, north of Espirito Santo state, southeastern Brazil from June 2015 to May 2016. We used 14 plots distributed in the Coastal Plain Forest following the RAPELD methodology of sampling. The frogs were sampled in transects along the plots, using the active search method, with visual and auditory sampling. We recorded two species of frogs (Aparasphenodon brunoi and Scinax argyreornatus) using PVC pipes as shelters in the plots in the Forest. Of the 468 PVC pipes established along plots, 38 of them (8.1%) were used as shelter by the frogs. For both frog species, about 33% of microhabitats used in the forest were the interior of PVC pipes. We concluded that the PVC pipes might constitute artificial shelters for at least two of the frog species living in the community of the Coastal Plain Forest, potentially being of relevance in conservation programs. In altered areas and those in which there has been the loss of types of microhabitats, the addition of these PVC pipes as artificial shelters may represent additional and complementary microhabitats to keep or increase the population stocks of arboreal and semi-arboreal frog species and having a size that allow them entering the shelter. These artificial shelters can play an important role in conservation of these frogs in fragmented areas where the availability of the microhabitats of these frog species were locally reduced.

Jedovatí obojživelníci

Some amphibians are poisonous, they produce toxins to defend themselves against predators or bacterial and fungal pathogens. With exception of certain salamanders (e.g. Pleurodeles waltl) and frogs (e.g. Corythomantis greeningi, Aparasphenodon brunoi), amphibians are not known to actively inject venom into bodies of other organisms. Poison dart frogs (Dendrobatidae) are well known for their brightly coloured skin. The frogs’ poison is found in special glands in their skin. This poison is so efficient that the native people of the South American Amazon rainforest use the frogs’ toxins on their weapons. Some people use the bufotoxins of some species of toxic toads (e.g. Bufo bufo, Incillus calvarius) as source of psychoactive substances, though this can be very dangerous.

Venomous Frogs Use Heads as Weapons

Venomous animals have toxins associated with delivery mechanisms that can introduce the toxins into another animal. Although most amphibian species produce or sequester noxious or toxic secretions in the granular glands of the skin to use as antipredator mechanisms, amphibians have been considered poisonous rather than venomous because delivery mechanisms are absent. The skin secretions of two Brazilian hylid frogs (Corythomantis greening and Aparasphenodon brunoi) are more toxic than the venoms of deadly venomous Brazilian pitvipers, genus Bothrops; C. greeningi secretion is 2-fold and A. brunoi secretion is 25-fold as lethal as Bothrops venom. Like the venoms of other animals, the skin secretions of these frogs show proteolytic and fibrinolytic activity and have hyaluronidase, which is nontoxic and nonproteolytic but promotes diffusion of toxins. These frogs have well-developed delivery mechanisms, utilizing bony spines on the skull that pierce the skin in areas with concentrations of skin glands. C. greeningi has greater development of head spines and enlarged skin glands producing a greater volume of secretion, while A. brunoi has more lethal venom. C. greeningi and A. brunoi have highly toxic skin secretions and an associated delivery mechanism; they are therefore venomous. Because even tiny amounts of these secretions introduced into a wound caused by the head spines could be dangerous, these frogs are capable of using their skin toxins as venoms against would-be predators.

Aparasphenodon brunoi Miranda-Ribeiro, 1920 (Anura: Hylidae): distribution extension and geographic distribution map for Bahia state, Brazil

The casque-headed frog Aparasphenodon brunoi is recorded for the first time in the municipalities of Ilhéus and Igrapiúna, southern region of Bahia state, northeastern Brazil. The new record of A. brunoi in the municipality of Igrapiúna, represents an increase of its known geographic distribution of approximately 150 km north from its nearest locality (airline), in municipality of Una, state of Bahia, representing now the northernmost known record for this species.

Frog species richness, composition and beta-diversity in coastal Brazilian restinga habitats

We studied the species richness and composition of frogs in 10 restinga habitats (sand dune environments dominated by herbaceous and shrubby vegetation) along approximately 1500 km of coastal areas of three Brazilian States: Rio de Janeiro (Grumari, Maricá, Massambaba, Jurubatiba and Grussaí), Espírito Santo (Praia das Neves and Setiba) and Bahia (Prado and Trancoso). We estimated beta-diversity and similarity among areas and related these parameters to geographic distance between areas. All areas were surveyed with a similar sampling procedure. We found 28 frog species belonging to the families Hylidae, Microhylidae, Leptodactylidae and Bufonidae. Frogs in restingas were in general nocturnal with no strictly diurnal species. The richest restinga was Praia das Neves (13 species), followed by Grussaí and Trancoso (eight species in each). The commonest species in the restingas was Scinax alter (found in eight restingas), followed by Aparasphenodon brunoi (seven areas). Our data shows that richness and composition of frog communities vary consistently along the eastern Brazilian coast and, in part, the rate of species turnover is affected by the distance among areas. Geographic distance explained approximately 12% of species turnover in restingas and about 9.5% of similarity among frog assemblages. Although geographic distance somewhat affects frog assemblages, other factors (e.g. historical factors, disturbances) seem to be also involved in explaining present frog assemblage composition in each area and species turnover among areas. The frog fauna along restinga habitats was significantly nested (matrix community temperature = 26.13 degrees; p = 0.007). Our data also showed that the most hospitable restinga was Praia das Neves and indicated that this area should be protected as a conservation unit. Frog assemblage of each area seems to partially represent a nested subset of the original assemblage, although we should not ignore the importance of historical factors. This nestedness pattern, in part, probably results from the intensive fragmentation of restinga habitats. Possibly, many frog species may have been lost in some studied areas as a result of the extensive habitat degradation to which restinga habitats are presently exposed.

THE TADPOLE OF THE CASQUE-HEADED FROG, APARASPHENODON BRUNOI MIRANDA-RIBEIRO (ANURA: HYLIDAE)

The tadpole of Aparasphenodon brunoi is described and illustrated for the first time (external morphology and internal oral features) from Maricá, State of Rio de Janeiro, Brazil. Characters of this tadpole include: body representing 30% of total length; eyes lateral; spiracle single, sinistral, with opening directed upward and backward; anal tube median; dorsal fin originating at the mid-third of body; caudal tip extended into a flagellum; oral disc anteroventral; and labial tooth row formula 2(2)/6(1). In general, body and tail brown. Tail with transverse dark brown stripes. Morphological comparisons were made with tadpoles of eight other pond and stream-dwelling casque-headed treefrog species of the genera Argenteohyla, Osteocephalus, and Trachycephalus. The tadpoles of the subspecies of Argenteohyla possess characteristics that may indicate full specific rank of these taxa, so that the taxonomic status of these subspecies should be revaluated. Considering that high number of tooth rows is usually associated with stream dwellers, the presence of this characteristic in A. brunoi tadpoles (a pond-dweller) may represent retention of an ancestral lotic pattern. Furthermore, the number of tooth rows in the posterior labium of A. brunoi corroborates the putative morphological synapomorphy of the tribe Lophiohylini (presence of at least four posterior labial tooth rows in the larval oral disc).

Ecological aspects of the casque-headed frog Aparasphenodon brunoi (Anura, Hylidae) in a Restinga habitat in southeastern Brazil

We describe some aspects of the ecology of Aparasphenodon brunoi, a species associated with bromeliads. We comment on the relationships of this species with bromeliad size, microhabitat use, diet and sexual dimorphism. This study was conducted on a Restinga habitat near Presidente Kennedy, state of Espírito Santo, southeastern coast of Brazil. When the animals were found inside the bromeliads, we measure bromeliad and head size of frogs. We analyzed stomach contents and determined the sex and reproductive condition. We found 17 individuals (58.6%) in bromeliad leafs, six (20.7%) in Cactaceae, three (10.3%) in liana and three (10.3%) on trunks. The correlation between head measurements and bromeliad size were high, indicating that animals apparently use bromeliads based on their size, which could be related to the minimization of water loss. The most common prey items were beetles, ants, and insect larvae, suggesting that the species is relatively generalist in prey consumption. Aparasphenodon brunoi showed significant sexual size and shape dimorphism with females having larger bodies than males (size) and females having tibia, eye diameter and SVL larger than males (shape), but larger sample size and more detailed ecological and life history data are needed to elucidate the factors that have led to sexual size dimorphism.

Comparative cytogenetic analysis on four tree frog species (Anura, Hylidae, Hylinae) from Brazil

A comparative cytogenetic analysis was carried out on four Hylinae tree frogs from Brazil (Aparasphenodon brunoi, Corythomantis greeningi, Osteocephalus langsdorffii, and Scinax fuscovarius) using Giemsa staining, BrdU replication banding, Ag-NOR staining, C-banding, DAPI and CMA₃ fluorochrome staining, and fluorescence in situ hybridization (FISH) with an rDNA probe. All the species share closely similar 2n = 24 karyotypes, almost indistinguishable by standard staining. The technique of BrdU incorporation allowed the identification of each pair of homologs and the establishment of extensive homeology for the great majority of the chromosomes, mainly of A. brunoi, C. greeningi, and O. langsdorffii. Despite highly conserved replication banding patterns, the use of the other banding techniques disclosed some minor differences, which reinforces the importance of extensive cytogenetic analyses for the karyotypic characterization of Anuran species. The present cytogenetic data confirm the closer proximity of A. brunoi, C. greeningi, and O. langsdorffii, whereas S. fuscovarius is phylogenetically more distant.

The occurrence of amphibians in bromeliads from a southeastern Brazilian restinga habitat, with special reference to Aparasphenodon brunoi (Anura, Hylidae).

Five species of anuran amphibians, all belonging to the family Hylidae, were collected at Praia das Neves, municipality of President Kennedy, southeastern Brazil. The species were represented by four genera: Scinax, Hyla, Aparasphenodon, and Trachycephalus. Four species (A. brunoi, Hyla albomarginata, Scinax altera, and S. cuspidatus) were found during the dry season (August 1999), and two (A. brunoi and Trachycephalus nigromaculatus) in the rainy season (February 2000). Aparasphenodon brunoi was the most abundant species in Praia das Neves. Some reproductive aspects and feeding habits of this hylid were investigated. Aparasphenodon brunoi was found mainly inside the bromeliad Aechmea lingulata, the largest plant analyzed. Fifteen specimens were collected during the dry season (August 1999) (11 males and 4 females). During the rainy season (February 2000), we collected 14 specimens (3 males, 10 females, and 1 juvenile). Sex-ratio was 1:1. Frogs ranged in snout-vent length from 31.2 to 69.3 mm. Females were larger than males. One female had 1,451 fully developed oocytes in her ovaries. The major groups of prey found in the stomachs were: Insecta, Myriapoda, and Arachnida. Blattodea, Orthoptera, Lepidoptera, and Hymenoptera (only ants) were the main food types in frequency, number, and weight. Aparasphenodon brunoi is a threatened species in many habitats of southeastern Brazil. Only natural vegetation protection may guarantee its survival during the immediate future.

Relacionamento entre anfíbios anuros e bromélias da restinga de Regência, Linhares, Espírito Santo, Brasil

Some anuran amphibians use the bromeliads during the entire life cycle and others only as diurnal shelter. At the sandy coastal plain of Linhares, State of Espirito Santo, Southeastern Brazil, 676 bromeliads were examined, of which 303 of Aechmea blanchetiana (Baker) L. B. Smith., 1955, 287 of Aechmea nudicaulis (L.) Griseb., 1864, and 86 of Vrisea procera (Mart. Ex Schult. f.) Wittm, 1891. The morphometric and physical-chemical analysis of different bromeliads evidenced variations among plants. During the period sampled, six anuran species were found inside the plant axils. The hylid frog Phyllodytes luteolus (Wied, 1824) was the most abundant species (260 specimens). Its abundance was higher in the epiphyte bromeliad Vrisea procera. Phyllodytes luteolus had higher occurrences in bromeliads located at a transitional area between open and under the shrub vegetation. Specimens of Scinax alterus (Lutz, B., 1973) and Aparasphenodon brunoi Miranda-Ribeiro, 1920, were more frequent mainly in transitional areas; Bufo granulosus Spix, 1824 occurred in open and transitional areas, whereas Gastrotheca fissipis (Boulenger, 1888) and Leptodactylus fuscus (Schneider, 1799) were found only in bromeliads located in open areas.

Evaporative water loss and oxygen uptake in two casque-headed tree frogs, Aparasphenodon brunoi and Corythomantis greeningi (Anura, Hylidae)

Evaporative water loss (EWL) and oxygen uptake (Vo 2) was measured in two species of tree frogs with cranial co-ossification, Aparasphenodon brunoi and Corythomantis greeningi. Both species use their head to seal the entrance of bromeliads, tree holes or rocky crevices used as shelters. EWL was significantly reduced in sheltered individuals of both species as compared with those exposed nude to desiccation. EWL per unit area through the head surface was significantly lower than the body skin for A. brunoi but not for C. greeningi. EWL per unit surface area through C. greeningi body skin was about 50% that of A. brunoi, indicating a less permeable skin in the former species. The relationship between cranial coossification and EWL is discussed. Vo 2 in A. brunoi was comparable with other anurans of similar size, whereas in C. greeningi, it was lower than predicted from body mass. Moreover, Vo 2 in C. greeningi showed less sensitivity to temperature increase than in A. brunoi. C. greeningi occurs in a drier environment than A. brunoi, and this appears to be reflected in their EWL and Vo 2 characteristics.