Embryonic morphology in five species of Hypsiboas (Anura: Hylidae)

NAVARRO ACOSTA, G.; BALDO, D; KOLENC, F; BORTEIRO, C; VERA CANDIOTI, MF

HERPETOLOGICAL JOURNAL

BRITISH HERPETOL SOC

Lugar: Montrose, Angus, UK; Año: 2017 vol. 26 p. 121 - 132

0268-0130

Research concerning the early development of anuran tadpoles has sparked new interest, ever since comparative studiesrevealed structural and temporal variations of embryonic stages within different taxonomic groups. In this paper we studiedthe early ontogeny of five species of the hylid genus Hypsiboas: H. curupi, H. pulchellus, H. riojanus and H. sp. from the H.pulchellus group, and H. faber from the homonymous group. We analyse the development of typical larval structures (oraldisc), and of embryonic transient structures (external gills, ciliated cells, hatching glands and adhesive glands). The diversityin structural patterns is mainly related to the number and size of external gills, size of the adhesive glands, ciliation densityand number of labial tooth ridges. In turn, heterochronic shifts mostly concern the time of adhesive gland division, and theregression of the hatching gland and ciliated cells. In some cases these variations appear to be related with oviposition sitesand environments where embryos and larvae develop. Hypsiboas faber embryos, which develop in small nests outside waterbodies, exhibit the largest hatching gland and large, densely ciliated and highly branched external gills as a possible responseto low oxygen environments. The large and persistent adhesive glands of H. curupi and H. sp. gr. pulchellus might be relatedto the development of embryos and larvae in small streams. Within the same intrageneric group, certain embryonic traitsof H. pulchellus (e.g., tooth row formula 2/3, minute external gills, low body ciliation) appear to be paedomorphic regardingancestral ontogenies, but the ecological/functional correlation (if any) of these features is uncertain.