A new species of Andean toad (Bufonidae, Osornophryne) discovered using molecular and morphological data, with a taxonomic key for the genus

Combining a molecular phylogeny and morphological data, we discovered a new species of Osornophryne from the Amazonian slope of the Ecuadorian Andes. Morphologically, the new taxon is distinguished from all others species in Osornophryne by having the Toes IV and V longer than Toes I-III, a short and rounded snout with a small rostral papilla, and conical pustules on flanks. The new species previously was confused with Osornophryne guacamayo. A taxonomic key is provided for all known species of Osornophryne.     

Removing the rubbish: frogs eliminate foreign objects from the body cavity through the bladder

During the course of a telemetry study on three species of Australian frogs (Litoria caerulea, Litoria dahlii and Cyclorana australis), we found that many of the surgically implanted transmitters had migrated into the bladder. We subsequently implanted small beads into L. caerulea and they were expelled from the body in 10-23 days. Beads implanted into cane toads (Rhinella marina) to document the process were either expelled or were enveloped into the bladder. This appears to be a unique pathway for expulsion of foreign objects from the body, and suggests that caution should be employed in telemetry studies when interpreting the separation of some animals from their transmitters as a mortality event.     

Male size does not correlate with fertilization success in two bufonid toads that show size-assortative mating

We examined sexual size dimorphism （SSD）, mating pattem, fertilization efficiency and female reproductive traits in two bufonid toads （Bufo gargarizans and Duttaphrynus melanostictus） to test the idea that importance of male body size for egg fertilization success depends on the mating pattern. Female-biased SSD was evident only in D. melanostictus. Female B. gar- garizans laid fewer larger eggs nearly three months earlier than did female D. melanostictus. Fertilization efficieneies on average were higher in B. gargarizans （95%） than in D. melanostictus （91%）. Though differing in the degree of SSD, body size, breeding season, clutch size, egg size and fertilization efficiency, the two toads were similar in four aspects： （1） both showed size-assortative mating; （2） females did not tradeoff egg size against egg number; （3） male size, clutch size and clutch dry mass were greater in male-larger than in female-larger pairs after accounting for female snout-vent length （SVL）; and （4） the ratio of male to female SVL did not affect fertilization efficiency. Our data show that： （1） a female preference for large males is likely not important in terms of egg fertilization success; （2） a male preference for large females is likely important because larger females are more fecund; and （3） size-assortative mating arises from a male preference for large females. Our study demonstrates that male size is not always important for egg fertilization success in anurans that show size-assortative mating.     

Trading heat and hops for water: Dehydration effects on locomotor performance,thermal limits,and thermoregulatory behavior of a terrestrial toad

Due to their highly permeable skin and ectothermy, terrestrial amphibians are challenged by compromises between water balance and body temperature regulation. The way in which such compromises are accommodated, under a range of temperatures and dehydration levels, impacts importantly the behavior and ecology of amphibians. Thus, using the terrestrial toad Rhinella schneideri as a model organism, the goals of this study were twofold. First, we determined how the thermal sensitivity of a centrally relevant trait—locomotion—was affected by dehydration. Secondly, we examined the effects of the same levels of dehydration on thermal preference and thermal tolerance. As dehydration becomes more severe, the optimal temperature for locomotor performance was lowered and performance breadth narrower. Similarly, dehydration was accompanied by a decrease in the thermal tolerance range. Such a decrease was caused by both an increase in the critical minimal temperature and a decrease in the thermal maximal temperature, with the latter changing more markedly. In general, our results show that the negative effects of dehydration on behavioral performance and thermal tolerance are, at least partially, counteracted by concurrent adjustments in thermal preference. We discuss some of the potential implications of this observation for the conservation of anuran amphibians.     

Development of integument and cutaneous glands in larval,juvenile and adult toads (Rhinella granulosa): a morphological and morphometric study

In this study, the development of integument and cutaneous glands in the toad Rhinella granulosa (Bufonidae) at different larval stages and in postmetamorphic and adult forms was examined. The analyses were conducted using histological, ultrastructural and morphometric methods. The results showed that cellular aggregations of precursor epidermal glands start to appear in stage 31 of (Herpetologica, 16, 1960 and 183) and then proliferate and invade the dermis. After stage 41, granular and mucous glands are very similar to those found in adults. The granular glands are syncytial and are surrounded by a distinct layer of myoepithelial cells. In the region of parotoid macroglands, the granular glands accumulate and their alveoli progressively increase until they reach adult size. An analysis by scanning electron microscopy showed the inner distribution of the syncytial nuclei and the myoepithelial cells. The morphological changes observed in the integument of tadpoles are associated with the gradual adaptation to terrestrial environments by preparing the individual for future chemical defence against predators and micro‐organisms.     

中国蟾蜍类一个新类群及其生物学

１９７３－１９９１年间,我们在中国云南西部先后发现了产卵于山溪急流水的蟾蜍卵及蝌蚪,因标本少和资料不会定为甸蟾蜍（杨大同等,１９７８,１９９１）,把蝌蚪误认为绿点湍蛙（耀明,１９８３）,以后多次在产地进行较长时间调查,掌握了繁殖季节,采集到大批成体,在野外找到了产卵场,观察了繁殖行为,产卵过程,以及在人工饲养了观察记录了产卵,孵化和发育的全过程;解剖了１０个成年个体,并与华西蟾蜍,黑眶蟾蜍等的蝌蚪     

Post‐metamorphic development of skin glands in a true toad: Parotoids versus dorsal skin

Chemical defenses in amphibians are a common antipredatory and antimicrobial strategy related to the presence of dermal glands that synthesize and store toxic or unpalatable substances. Glands are either distributed throughout the skin or aggregated in multiglandular structures, being the parotoids the most ubiquitous macrogland in toads of Bufonidae. Even though dermal glands begin to develop during late‐larval stages, many species, including Rhinella arenarum , have immature glands by the end of metamorphosis, and their post‐metamorphic growth is unknown. Herein, we compared the post‐metamorphic development of parotoids and dorsal glands by histological and allometric studies in a size series of R. arenarum . Histological and histochemical studies to detect proteins, acidic glycoconjugates, and catecholamines, showed that both, parotoids and dorsal glands, acquire characteristics of adults in individuals larger than 50 mm; that is, a moment in which the cryptic coloration disappears. Parotoid height increased allometrically as a function of body size, whereas the size of small dorsal glands decreased with body size. The number of glands in the dorsum was not linearly related to body size, appearing to be an individual characteristic. Only adult specimens had intraepithelial granular glands in the duct of the largest glands of the parotoids. Since toxic secretions accumulate in the central glands of parotoids, allometric growth of parotoids may translate into greater protection from predators in the largest animals. Conversely, large glands in the dorsum, which produce a proteinaceous secretion of unknown function, grow isometrically to body size. Some characteristics, like intraepithelial glands in the ducts and basophilic glands in the dorsum, are limited to adults.     

Amphibians distribution and habitats in the southwestern region of Saudi Arabia

This study surveyed 205 wetland sites in the Southwestern Saudi Arabia. We found seven species of amphibians (Anura), which belong to four families: Bufonidae; which includes four species, Sclerophrys tihamica; S. Arabica, Duttaphrynus dhufarensis, and Bufotes viridis; Hylidae, represented by only one species, the tree frog Hyla savignyi; Ranidae, which represented by one species, Pelophylax ridibundus and finally the Dicroglossidae, represented by one species, Euphlyctis ehrenbergii. The reasonable amount of rain received in southwest Arabia, and habitat diversity contribute to the relative abundance of amphibians in the region. Five types of wetland habitats were found in the study area. Valley streams, irrigated farms, seasonal ponds, dam reservoir and lagoons of treated sewage water. The current study revealed the wide spread of amphibians in southwestern Saudi Arabia than what had been reported earlier and confirmed the presence of the Bufotes viridis at three new sites in Asir Heights. It also showed the wide spread of S. arabica in all types of habitats in the southwestern region of Saudi Arabia. Habitat degradation was evident in the region, which might lead to species loss.     

Apoptosis,proliferation and presence of estradiol receptors in the testes and Bidder's organ of the toad Rhinella arenarum (Amphibia,Anura)

The dynamic equilibrium between spermatogonial proliferation and testicular apoptosis determines the progression of spermatogenesis in amphibians. Estrogens and their receptors play a central role in regulating spermatogenesis in vertebrates, and in some species of anurans, estradiol (E₂) is involved in the regulation of spermatogonial proliferation and apoptosis of germ cells. Bidder's organ (BO) is a structure characteristic of Bufonidae that has historically been compared to an undeveloped ovary. In adult Rhinella arenarum males, BO is one of the main sources of plasma E₂. The aim of this study was 1) to describe the seasonal variations in testicular apoptosis, spermatogonial proliferation, and cellular proliferation in BO; and 2) to analyze the presence and localization of estrogen receptor β (ERβ) in the testes and BO of R. arenarum. Testicular fragments and BOs from animals collected during the year were labeled with 5‐bromo‐2′‐deoxyuridine (BrdU) and BrdU incorporation was determined using immunohistochemistry. Apoptosis in testicular sections was detected using the TUNEL method, and ERβ localization was assessed using immunohistochemistry in testes and BOs. The results indicate that spermatogonial proliferation is highest during the reproductive season and that cysts of spermatocytes and spermatids undergo apoptosis during the postreproductive season. Furthermore, the proliferation of follicular cells is highest during the reproductive and postreproductive seasons. ERβ was primarily detected by immunolocalization in Sertoli cells, follicular cells, and oocytes. Taken together, these results suggest that cysts that do not form spermatozoa are removed from testes by apoptosis and that estrogens regulate both spermatogenesis and oogenesis in adult males of R. arenarum. J. Morphol. 277:412–423, 2016. © 2015 Wiley Periodicals, Inc.     

Trait independence primes convergent trait loss

The repeated, independent evolution of traits (convergent evolution) is often attributed to shared environmental selection pressures. However, developmental dependencies among traits can limit the phenotypic variation available to selection and bias evolutionary outcomes. Here, we determine how changes in developmentally correlated traits may impact convergent loss of the tympanic middle ear, a highly labile trait within toads that currently lack adaptive explanation. The middle ear's lability could reflect evolutionary trade‐offs with other skull features under selection, or the middle ear may evolve independently of the rest of the skull, allowing it to be modified by active or passive processes without pleiotropic trade‐offs with other skull features. We compare the skulls of 55 species (39 eared, 16 earless) within the family Bufonidae, spanning six hypothesized independent middle ear transitions. We test whether shared or lineage‐specific changes in skull shape distinguish earless species from eared species and whether earless skulls lack other late‐forming skull bones. We find no evidence for pleiotropic trade‐offs between the middle ear and other skull structures. Instead, middle ear loss in anurans may provide a rare example of developmental independence contributing to evolutionary lability of a sensory system.