First records of advanced embryos and egg capsules of Bathyraja skates from the deep north-eastern Atlantic

Five variously developed embryos 142–279 mm total length (L_T)] from egg capsules from the Porcupine Seabight, north-eastern Atlantic (1541 m depth) are used to establish the ontogeny and early life history of Bathyraja richardsoni. The capsules of this species and two half-formed ones from the shell glands of a large (1620 mm L_T) female Bathyraja pallida taken off Ireland (c. 1900 m depth) are described and illustrated. The varying degree of yolk sac absorption found in the B. richardsoni embryos is discussed in relation to hatching size and its seeming size independence over c. 20–50 mm within the embryos' total length range. The conservative variation in external morphology with development from advanced embryos to adults among such deep stenobathic Bathyraja skates is commented upon, as is the bathymetric segregation of adults from levels in which egg capsules are deposited and young develop.