Description of the egg cases and juvenile colouration in two catsharks of the genus Atelomycterus (Carcharhiniformes: Scyliorhinidae)

Abstract

Descriptions of egg cases and hatchlings of the Bali catshark Atelomycterus baliensis and the Australian marbled catshark Atelomycterus macleayi are provided. Comparisons are made with two of their congeners, banded sand catshark Atelomycterus fasciatus and coral catshark Atelomycterus marmoratus. The Atelomycterus egg cases have the same general morphology, i.e., elongate with anterior and posterior waists, a depressed and truncate anterior end sometimes with attachment fibres, a medially tapered posterior end with two horns sometimes terminating in short, tightly curled tendrils and four respiratory fissures (one at each left corner on opposing sides). Morphometric measurements taken of the egg cases of the four species differed significantly when subjected to multivariate analysis, with unique characters enabling distinction between them. The morphological characters that best distinguished the Atelomycterus species from each other were anterior border width, posterior waist width and posterior case width. Thus, egg case morphology could be used to distinguish the egg cases of the four Atelomycterus species examined, consistent with other studies on scyliorhinid and pentanchid egg cases. Colouration of A. baliensis and A. macleayi juveniles was similar to that of other Atelomycterus juveniles in being pale with a series of dark-brown distinct dorsal saddles along the body, blotches and sometimes with a low number of small dark spots.

Dichichthyidae, a New Family of Deepwater Sharks (Carcharhiniformes) from the Indo–West Pacific, with Description of a New Species

“…Fishes 2024, 9, 121 3 of 48 Egg case morphological measurements followed those proposed in [27] with the addition of egg case body length and maximum egg case width following [28] for skates. Two additional measurements specific to this genus of sharks were also taken: the depth of the single lateral keel on the left side of the egg case and the depth of the lower (broader) lateral keel on the right side of the egg case.…”

What came first, the shark or the egg? Discovery of a new species of deepwater shark by investigation of egg case morphology

“…Egg case morphology in sharks has been shown to be a valuable taxonomic character for distinguishing between taxa ( e.g ., Flammang et al ., 2007; O'Neill et al ., 2020). Nonetheless, the egg cases of many oviparous species are not known or not well defined.…”