Deep-sea cryptobranch dorid nudibranchs (Mollusca, Opisthobranchia) from the tropical West Pacific, with descriptions of two new genera and eighteen new species

Authors
Citation
A. Valdes, Deep-sea cryptobranch dorid nudibranchs (Mollusca, Opisthobranchia) from the tropical West Pacific, with descriptions of two new genera and eighteen new species, MALACOLOGIA, 43(1-2), 2001, pp. 237-311
Citations number
55
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Animal Sciences
Journal title
MALACOLOGIA
ISSN journal
0076-2997 → ACNP
Volume
43
Issue
1-2
Year of publication
2001
Pages
237 - 311
Database
ISI
SICI code
0076-2997(2001)43:1-2<237:DCDN(O>2.0.ZU;2-A
Abstract
The study of a large collection of cryptobranch dorid nudibranchs from deep waters in New Caledonia and the Philippines revealed the presence of Austr odods kerguelenensis (Bergh, 1884); 18 new species belonging to the genera Cadlina, Austrodoris, Geitodods, Discodoris, Peltodoris, Paradoris, Diaulul a, Rostanga, Sclerodoris, Baptodoris and Dendrodoris, and two previously un described genera, Goslineria and Pharodoris, The anatomy of all these speci es, including the digestive, reproductive, and nervous system, are studied in detail. All these species are clearly distinguishable from other members of their g enera. Most of the species have a pale, simple background coloration, and t wo of them lack eyes. Both characteristics seem to be adaptations to living in deep waters. Other deep-water Atlantic and Pacific species of dorid nud ibranchs have similar adaptations. The two new genera are characterized by the presence of large copulatory spines, numerous flexible spines in Goslin eria, and two solid, bifid spines in Pharodoris. No other cryptobranch dori d genera previously described have similar copulatory spines. Some of the species here described belong to genera previously reported fro m cold or temperate waters, such as Austrodoris, Cadlina and Diaulula. Most of the species belong to genera that are widespread in either cold, temper ate or tropical waters (Rostanga, Paradoris, Geitodods and Baptodoris), and only two belong to exclusively tropical genera (Sclerodoris and Dendrodori s). Vicariant events and vertical dispersal could explain the processes of speciation and the origin of these deep-water species.