Morphological and biological characteristics of a gravid angular rough shark (Oxynotus centrina) and its embryos from the Eastern Mediterranean Sea
The record of a specimen of gravid female angular rough shark, Oxynotus centrina, in the Aegean Sea is reported. It was captured in February 1999 by a commercial bottom trawl at a depth of 100 to 200 m on a muddy-sandy bottom near Kea Island. The specimen size was 69 cm in total length and 4.0 kg in weight. A total of fifteen embryos ranging from 9.0 to 11.2 cm in total length were observed. They all had a distinctive coloration of darker marks on a light brownish background. All the embryos were attached to sizeable yolk sacs but showed differences in development; some had already absorbed a significant part of yolk sac content, while others had not. All embryos had clearly formed external morphological characteristics, similar to the adult stage. No sign of clasper formation was observed, making sex identification impossible. One of the embryos was significantly smaller and malformed in the head area. A series of morphometric measurements were taken both for gravid female and embryos and compared to each other.