caa a22 4500 463255232 CHVBK 20180405153352.0 cr unu---uuuuu 170326e20070801xx s 000 0 eng 10.1007/s00435-007-0032-6 doi (NATIONALLICENCE)springer-10.1007/s00435-007-0032-6 Larval growth and perimetamorphosis in the echinoid Echinocardium cordatum (Echinodermata): the spatangoid way to become a sea urchin [Elektronische Daten] [C. De Amaral P. Nunes, M. Jangoux] The prejuvenile development of Echinocardium cordatum (Echinoidea) was investigated by means of scanning electron, confocal and light microscopes, aiming to illustrate the early life history of a spatangoid representative and to compare it with the other major echinoid groups. During the larval development of E. cordatum, two periods follow one another. The first one takes 12days; it ends with the formation of a complete echinopluteus with twelve elongated larval arms. The second lasts from 3 to 12days; it is entirely devoted to the building of the echinid rudiment and ends with the acquisition of larval competence. No appendage other than arms develops at the larva's outer surface. Competent larvae are demersal. They settle onto the substratum and test it for suitability using the five rudiment podia that protrude through the vestibule opening. Metamorphosis is a rapid event that lasts less than an hour. The rudiment does not everse and its spines and podia actively tear up the larval epidermis which is progressively covered by the growing vestibular epidermis. The resulting postlarva is short-lived and morphologically similar to both the late rudiment and the early juvenile, which, however, is exotrophic. Late rudiments in E. cordatum show basic spatangoid features being bilaterally symmetric and having clavulae and sphaeridia. More importantly, they already have the convex shape and the appendage cover of early juveniles. Metamorphosis in E. cordatum appears to be less complex, i.e. no rudiment is everted, and more complete, since, in contrast to "regular” echinoids, no transitory appendages are seen. Metamorphosis/development of E. cordatum, thus, is closer to that of clypeasteroids, since the rudiment of the latter already bears juvenile definitive appendages, when everted during metamorphsis. Springer-Verlag, 2007 Echinocardium cordatum nationallicence Development nationallicence Larval growth nationallicence Metamorphosis nationallicence Postlarva nationallicence De Amaral P. Nunes C. Service de Biologie Marine, Université Libre de Bruxelles (C.P. 160/15), 50, Av. F. D. Roosevelt, 1050, Brussels, Belgium aut Jangoux M. Service de Biologie Marine, Université Libre de Bruxelles (C.P. 160/15), 50, Av. F. D. Roosevelt, 1050, Brussels, Belgium aut Zoomorphology Springer-Verlag 126/2(2007-08-01), 103-119 0720-213X 126:2<103 2007 126 435 https://doi.org/10.1007/s00435-007-0032-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00435-007-0032-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- De Amaral P. Nunes C. Service de Biologie Marine, Université Libre de Bruxelles (C.P. 160/15), 50, Av. F. D. Roosevelt, 1050, Brussels, Belgium aut NATIONALLICENCE 700 1- Jangoux M. Service de Biologie Marine, Université Libre de Bruxelles (C.P. 160/15), 50, Av. F. D. Roosevelt, 1050, Brussels, Belgium aut NATIONALLICENCE 773 0- Zoomorphology Springer-Verlag 126/2(2007-08-01), 103-119 0720-213X 126:2<103 2007 126 435 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer