How can ontogeny help us to understand the morphology of anuran pectoral girdle?

Abstract

The ontogenetic development of the pectoral girdle in seven anuran species (Xenopus laevis, Discoglossus pictus, Bombina bombina, Bombina variegata, Pelobates fuscus, Bufo bufo and Rana dalmatina) was studied using cleared and stained specimens. The epicoracoid cartilage was found to develop in two different ways resulting in an arciferal or firmisternal type of the pectoral girdle. In the arciferal one, the epicoracoid originates from a medial prolongation of the procoracoid cartilage and broadly overlaps its counter part during further development. In the firmisternal pectoral girdle, the epicoracoids are formed by the widened cartilaginous medial edges of the coracoids that fuse together along the midline. Polarization of ontogenetic characters shows, that omosternum evolves inside Anura, and the type of sternum occurring in basal Anura seems to be an apomorphy of all Batrachia. The sternal elements have a single or paired rudiment, their development is connected with M. rectus abdominis or a zonal area and they remain cartilaginous or ossify during postmetamorphic development. An occurrence of omosternum in Barbourula busuangensis was described for the first time.

Comparative anatomy and development of pectoral and pelvic girdles in hylid anurans

“…Differences in the timing of appearance of some structures such as mesenchymal condensations or premyogenic masses, generate interesting heterochronic patterns, particularly in pseudids. These patterns are in accord with the many literature reports of frequent heterochronic changes in pseudids (de S a & Lavilla, 1997;Fabrezi, Quinzio, & Goldberg, 2009, 2010. A general delay in the developmental processes which also characterize other aquatic species such as Telmatobius (Barrionuevo, 2013) and Xenopus laevis (Porro & Richards, 2017), is thought to be related to spending more time in the water (Laurin, Girondot, & Loth, 2004).…”

“…Because both girdles are equally important to move the limbs efficiently, there have been a considerable number of studies of the pectoral girdle (Baleeva, ; Borkhvardt & Baleeva, ; McGonell, ; Robovská‐Havelková, ; Shearman, , ) and the pelvic girdle (Manzano, Abdala, Ponssa, & Soliz, ; Manzano & Barg, ; Pomikal, Blumer, & Streicher, ; Ročková & Roček, ; Simons, ). However, the lack of studies that compare the anatomy and development of both girdles is striking (see Carroll & Holmes, ; Sears et al, ).…”

The Gondwana Breakup and the History of the Atlantic and Indian Oceans Unveils Two New Clades for Early Neobatrachian Diversification

“…Many members of our new clade share a unique feature in which there is no ossification of the coracoides bones. Curiously, this trait was once suggested as exclusive to the old Arcifera group, originally proposed by Boulenger in his classic monograph [ 46 , 47 ]. The phylogeny underlining members of the Arcifera group is available in S3 Fig .…”

Digital dissection of the model organism Xenopus laevis using contrast‐enhanced computed tomography

“…Subsequently, certain anatomical regions have been described in varying levels of detail, including: the pelvic and proximal hind limb skeleton and musculature (Green, ; Dunlap, ; Palmer, ; Emerson, ; Van Dijk, ; Ročkova & Roček, ; Přikryl et al. ); the pectoral skeleton (Robovská‐Havelková, ); the abdominal wall (Ryke, ); and the head skeleton and musculature (Paterson, ; Trueb & Hanken, ; Roček, ; Smirnov, ; Hass, ; Ziermann & Olsson, ; Gross & Hanken, ; Ziermann & Diogo, ), particularly with regards to development. Excellent dissection guides for frogs are available (Minkoff, ), including the classic work by Ecker () that uses several species of the neobatrachid Rana as the basis for anuran anatomy.…”