Egg-capsules, eggs and embryos of the gastropod Trophon acanthodes (mollusca: muricidae) and its new generic position

GUIDO PASTORINO; PABLO E. PENCHASZADEH

JOURNAL OF MOLLUSCAN STUDIES

OXFORD UNIV PRESS

Año: 2009 vol. 75 p. 337 - 341

0260-1230

The egg capsules, eggs and embryos of the muricid gastropod Trophon acanthodes are described for thefirst time. Egg capsules are sessile, bulliform, semi-circular, about 20 mm in diameter, with a plug inthe centre of the dorsal side. Sutures divide the capsule into two slightly asymmetrical halves.Recently-laid egg capsules contained about 6,000 uncleaved eggs with a diameter of 213–236 mm.The number of early embryos was 7–9 with a size of 320 320 to 820–880 mm. Nine prehatchingembryos of 3.94 mm maximum shell height were found inside an older egg capsule without intracapsulareggs. Therefore it is concluded that several thousand nurse eggs were present when laid. SEMillustrations of shell embryos and radulae are provided. Comparison of shell and radula of embryoswith the protoconch and radula of adults of T. acanthodes confirms that the egg capsule belongs tothis species. Coronium coronatum has an extremely similar protoconch and this, together with thesimilar egg capsule morphology that is different from that of Trophon geversianus, supports the reassignmentof T. acanthodes to the genus Coronium.