Biodiversity of the Mediterranean Opisthobranch Gastropod Fauna: Historical and phylogenetic perspectives.

Resumen

Opisthobranch gastropods are marine animals that differ from most other mollusks in having a reduced shell. The systematics, therefore, is based largely on the study of the soft parts, and this attracts a distinct group of specialists. Explorers of the Mediterranean opisthobranch fauna include a substantial number of persons who traveled in the area such as August Krohn (1803–1891) and Amandus Philippi (1808–1904). More substantial contributions were made by scientists who had academic positions that were located at appropriate places near the shore. Naples was a particularly active center of investigation, all the more so after the founding of the Zoological Station by Anton Dohrn. A major specialist on the group, Salvatore Trinchese (1836–1897) was influential in both research and teaching. Both he and his students occupied “tables” at the Station. French scientists did not work at the Station, but they had their own institutions. A good example is Albert Vayssière (1854–1942), who held academic positions at the University of Marseille and was active in research there for many years. In recent years, scientists of many nationalities have been involved in studying the opisthobranch fauna, and the Portuguese and Spanish provide an instructive example. The Portuguese and Spanish tradition in opisthobranch taxonomy began in the latter part of the 19th century, but then languished for many decades during the Spanish Civil War and Franco era. The study of Iberian opisthobranchs underwent a renaissance in the 1970s and has come into full flower in the last decade. Resident workers are actively working on the fauna, training students, and developing an enduring tradition of systematic and phylogenetic study that is international in scope and impact. The result of many years of study has been the establishment of a well documented inventory of the opisthobranchs of the Mediterranean. On the basis of such lists, it is possible to document many trends in the investigation of the fauna and better to understand the results. The number of names introduced provides an index of such phenomena as the amount of research effort. The number of synonyms provides one way of assessing the quality of systematic work. In addition, it is possible to document changes in the composition of the fauna due to such phenomena as introduction of alien elements. Today, opisthobranchs play an increasing important role in studies of physiology, ecology, and evolution.