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...     

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.     

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.     

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.     

Cytogenetic analysis of two species in the Phyllomedusa hypochondrialis group (Anura, Hylidae)

The genus Phyllomedusa has been the target of regular taxonomic investigations. The species Phyllomedusa nordestina was recently separated from P. hypochondrialis. Morphological variations in the P. rohdei interpopulation have already been reported, suggesting the existence of more than one taxon under that name. In the present study, we have cytogenetically characterized two populations of P. nordestina and one of P. rohdei. Both species displayed 2n = 26 chromosomes with 12 metacentric, 12 submetacentric and 2 subtelocentric chromosomes. The C-banding analyses revealed discrete differences in the quantity of centromeric heterochromatin between the two species. The nucleolus organizer region (NOR) was detected in pair 9 of both species, but is located in the pericentromeric region of the short arm in P. nordestina and in the long arm subtelomeric region of P. rohdei. Chromosomal data from this study indicate karyotypic homeology between the two groups of P. hypochondrialis species and suggest the existence of more than one taxon under the P. rohdei name.     

The annual reproductive cycle of the Smooth newt (Triturus vulgaris) in England

Newts were collected throughout the year from both breeding ponds and terrestrial sites and were weighed, measured and dissected; in males, the testes were examined histologically. Smooth newts show post-nuptial gametogenesis such that, during late summer and autumn they are producing mature gametes for the following year's breeding season. In males, the testes are at their smallest size during the spring, when they consist mostly of immature sperm cysts and evacuated tissue, mature sperm having been evacuated into the vasa deferentia during the newts' migration to water. Evacuated testicular tissue is glandular in function and there is evidence that secretions from this tissue control the development of secondary sexual characters: the dorsal crest, fringes of skin on the toes and the dorsal cloacal gland. In both sexes, fat body and liver weights are lowest in the spring and increase in the autumn. In females, oocytes vary in size, depending on the amount of yolk they contain. Only the larger oocytes are laid in a current breeding season, the smaller ones being retained and yolked in late summer and autumn. In both sexes, measures of fecundity (testis size in males, oocyte number in females) are strongly correlated with body size. The finding that male newts have a finite supply of sperm during the breeding season leads to an interpretation of various aspects of male courtship behaviour. These are adaptations for conserving sperm and allocating it to courtship encounters in a way likely to promote male reproductive success.     

The annual reproductive cycle of the Barbary Ape (Macaca sylvana) in Gibraltar

Data collected in Gibraltar demonstrate that Macaca sylvana has both a sharply demarcated mating and a sharply demarcated birth season. The mating season begins in November and may last until March. Births occur between May and September, gestation being of five or six months' duration. The annual reproductive cycle of the Japanese macaque is strikingly similar to that of the Barbary Ape. Matings occur in both areas in the fall, a period of decreased daily temperature and day length. The mating season begins with an increase in rainfall in Gibraltar and with a decrease in rainfall in Japan. From the data presented it seems probable that decreasing day length is the most important ecological factor in the timing of the onset of mating in Barbary Apes and in Japanese macaques.     

Photoperiod influences the annual reproductive cycle of the male pallid bat (Antrozous pallidus)

Adult pallids bats collected in April or May, were maintained in short or long photoperiods (10 or 14 h light/day) for 3-6 months. In August, the short-day bats had regressed testes, epididymal spermatozoa and fully developed accessory sex glands, corresponding to the autumnal reproductive condition of field animals; long-day bats had testes undergoing spermatogenesis, few epididymal spermatozoa and undeveloped accessory sex glands (summer reproductive condition). Bats in each photoperiod manifested the expected autumnal reproductive pattern in October. We suggest that photoperiod influences the reproductive physiology of male pallid bats by affecting an endogenous circannual reproductive rhythm.     

Chondrocranium and cranial muscle morphology in Lysapsus and Pseudis tadpoles (Anura: Hylidae: Hylinae)

The chondrocranium and cranial muscles of Lysapsus limellum, Pseudis cardosoi, P. minuta and four subspecies of P. paradoxa (caribensis, occidentalis, paradoxa and platensis) are described. Lysapsus and Pseudis are related to the Hylidae by: (1) vertical processus anterolateralis of the larval crista parotica, and (2) presence of m. mandibulolabialis inferior and superior (the latter reversed in P. cardosoi). We confirm some larval synapomorphies previously proposed for the pseudids, except the m. subarcualis obliquus II having one head and the absence of copula anterior. We add three new features for the pseudids: (1) the distal end of ceratobranchiales III and IV projects towards either the capsula auditiva (Lysapsus) or the processus basicapsularis – new term – (Pseudis); (2) the arcus subocularis is twice as wide at the level of the processus ascendens as it is just posterior to the processus muscularis quadrati, and (3) the lateral corner of the processus articularis quadrati largely projects laterally. We diagnose Lysapsus larvae (the states of Pseudis in parentheses) as follows: (1) short processus pseudopterygoideus (long), (2) absence of lateral development of larval crista parotica (presence), (3) absence of commissura proximalis II (presence), (4) presence of processus lateralis hyalis – new term – (absence), (5) absence of processus basicapsularis (presence), (6) processus ascendens slightly curved along its entire extent (curved at the union with the basi cranii only), and (7) absence of m. tympanopharyngeus (presence).     

Nuclear pore dynamics during the cell cycle

A nuclear pore complex (NPC) is a large protein assembly that mediates the nucleocytoplasmic exchange of molecules. During the cell cycle, NPCs assemble, disassemble, and dynamically change their distribution on assembled nuclear envelope (NE), whereas in post-mitosis, NPCs are extremely stable. Extensive studies on its components, structure, and building blocks allow the study of its assembly and disassembly at the molecular level. Depending on the location that the initial components of this structure are built (e.g. chromatin versus double lipid bilayers of the nuclear envelope), the regulation and the mechanism of the assembly differ. Moreover, cell cycle dynamics of NPC are linked with INM proteins, lamins, lipid membranes, and the cell cycle signal, which show that NPC dynamics are highly regulated processes.     

New species of Falcaustra (Nematoda: Kathlaniidae) in Nyctimystes cheesmani (Anura: Hylidae) from Papua New Guinea

Falcaustra batrachiensis n. sp. (Ascaridida, Kathlaniidae) from the large intestine of Nyctimystes cheesmani (Anura, Hylidae) is described and illustrated. Falcaustra batrachiensis represents the fifth Australo-Papuan species assigned to the genus and is distinguished from other Australo-Papuan species by the distribution pattern of the caudal papillae (8 precloacal, 2 adcloacal, 6 postcloacal, and 1 median), length of spicules (1.4-1.6 mm) and presence of pseudosuckers (5 or 6). Nyctimystes cheesmani was found to harbor 7 additional species of Nematoda, adults of Cosmocerca novaeguineae, Maxvachonia ewersi, Meteterakis crombiei, Physalopteroides milnensis, Pseudorictularia dipsarilis, Seuratascaris numidica, larvae in cysts of Abbreviata sp., and 1 species of Acanthocephala, Acanthocephalus bufonis. Nyctimystes cheesmani represents a new host record for each of these helminth species.     

Temporal and Geographic Variation in the Advertisement Call of the Booroolong Frog (Litoria booroolongensis: Anura: Hylidae)

The mechanisms that underlie sexual selection rely upon within‐ and among‐individual variability in the targeted traits. In this study, we examined variation in the advertisement call of the booroolong frog (Litoria booroolongensis) at several different levels: between populations, between breeding seasons in the same population, among males within a population, within males between nights and within males in a single calling bout. The call of L. booroolongensis has multiple notes with a pulsed structure. We detected considerable variation in advertisement call structure between breeding seasons and between populations. The measured call properties ranged from static to dynamic; however, most properties were intermediate between the criteria that have been traditionally used to define call traits as static or dynamic (≤5 and ≥12% respectively). We compared actual and relative repeatabilities and found that the temporal call properties associated with the structure of the note had the highest values, suggesting that these characters in particular may respond to selection. We argue that relative repeatabilities are a particularly useful measure of the potential for evolutionary response to selection as they account for an individual's relative performance during the period of assessment in an ever‐changing breeding arena.