Patterns of allometric and heterochronic changes in the early ontogeny of species of Physalaemus (Anura: Leptodactylidae).

We studied the relationship between shape, size, and developmental time in the embryonic ontogeny of 15 species of the frog genus Physalaemus. As in other anuran exotrophic embryos, shape changes are correlated with size increase and mainly concern tail elongation, decrease in body height, and increase in fin height. Size ranges and developmental times vary interspecifically. Embryos of the P. signifer Clade and the P. gracilis Group are among the largest, are slightly peramorphic, and develop fast regarding congeneric species. Embryos of P. cicada combine the smallest sizes with fast development and the most peramorphic shapes. The paedomorphic shapes of embryos of P. biligonigerus and P. henselii groups are correlated with fast vs. slow developmental times respectively. Trajectories in the P. cuvieri Group are diverse and in general differ in size and developmental time. The embryos of P. cristinae and from the Argentinean lineage of P. cuvieri stand out with the longest development. Sequences of developmental events are overall conserved in the genus, and main differences concern mouthpart ontogeny. This study constitutes the first attempt to evaluate morphological, allometric, and heterochronic parameters of the early ontogeny of anurans and how these can vary and contribute to diversification in taxonomic groups.

Amphibians in Zootaxa: 20 years documenting the global diversity of frogs, salamanders, and caecilians.

Zootaxa is a mega-journal that since its inception, 20 years ago, has contributed to the documentation of the planet's biodiversity. Its role concerning terrestrial vertebrates has been crucial especially for amphibians, which are the most threatened class of vertebrates. As current editors of the Amphibia section, we reviewed the state of knowledge of taxonomic publications on amphibians over the last two decades (from 2001 to 2020). Our review reveals that 2,533 frogs, 259 salamanders, and 55 caecilians have been named in these 20 years, mainly in the tropical regions of South America, Asia, and Africa. More than half (57%) of these species descriptions were published in only 10 journals. At least 827 species of the new amphibians (29% of the total) were described in Zootaxa. This mega-journal has served also as a place of publication for monographs and systematic reviews, in addition to short articles documenting the vocalizations of anurans and the morphology of embryos and larvae. Its efficient evaluation process, the freedom of manuscript length, including full-color figures, and free of cost for the authors, has made Zootaxa a favorite for amphibian researchers. In an era of accelerating rates of biodiversity loss, documenting, describing, naming, and proposing evolutionary scenarios for species is, more than ever, an urgent task.

Embryonic ontogeny of three species of Horned Frogs, with a review of early development in Ceratophryidae.

Horned Frogs of the family Ceratophryidae are conspicuous anurans represented by three endemic South American genera. Most ceratophryids inhabit semiarid environments, but three species of Ceratophrys occupy tropical or temperate humid areas. Several morphological and behavioral characters of larvae and adults are conserved across the family. Based on examination of specimens and accounts in the literature, the embryonic development of C. ornata, C. cranwelli, and the monotypic genus Chacophrys are described and compared with that of species of Lepidobatrachus. Ceratophryid embryos share a suite of morphological features and heterochronic shifts during development. Most features, such as gill structure, ciliation, early hatching, and precocious differentiation of the gut and hind limbs, are shared by all the species regardless the differences in the habitats that occupy. This is consistent with previous observations of some adult characters, and likely supports the hypothesis of an early diversification of ceratophryids in semiarid environments. Other embryonic features, such as the morphology and ontogeny of the oral disc and digestive tract, are correlated with larval feeding habits and vary within the family. The evolutionary and ecological significance of some conserved characters (e.g., gastrulation pattern, Type-A adhesive glands) and other taxon-specific features (e.g., nasal appendix) remain to be explored in the group.