Megafauna of the German exploration licence area for seafloor massive sulphides along the Central and South East Indian Ridge (Indian Ocean).

BACKGROUND: The growing interest in mineral resources of the deep sea, such as seafloor massive sulphide deposits, has led to an increasing number of exploration licences issued by the International Seabed Authority. In the Indian Ocean, four licence areas exist, resulting in an increasing number of new hydrothermal vent fields and the discovery of new species. Most studies focus on active venting areas including their ecology, but the non-vent megafauna of the Central Indian Ridge and South East Indian Ridge remains poorly known.In the framework of the Indian Ocean Exploration project in the German license area for seafloor massive sulphides, baseline imagery and sampling surveys were conducted yearly during research expeditions from 2013 to 2018, using video sledges and Remotely Operated Vehicles. NEW INFORMATION: This is the first report of an imagery collection of megafauna from the southern Central Indian- and South East Indian Ridge, reporting the taxonomic richness and their distribution. A total of 218 taxa were recorded and identified, based on imagery, with additional morphological and molecular confirmed identifications of 20 taxa from 89 sampled specimens. The compiled fauna catalogue is a synthesis of megafauna occurrences aiming at a consistent morphological identification of taxa and showing their regional distribution. The imagery data were collected during multiple research cruises in different exploration clusters of the German licence area, located 500 km north of the Rodriguez Triple Junction along the Central Indian Ridge and 500 km southeast of it along the Southeast Indian Ridge.

Zevinaella-a new barnacle genus (Scalpellomorpha: Arcoscalpellinae) associated with crinoids (Echinodermata) from the Caribbean.

A new genus, Zevinaella (Cirripedia: Scalpellomorpha: Scalpellidae: Arcoscalpellinae), is proposed to accommodate Trianguloscalpellum rodstromi (Boone, 1927) from Belize and Z. volentis gen. et sp. nov. from the Lesser Antilles, both occurring on crinoids. These two species are unique in lacking lower lateral plates (inframedian or second latera, L2s). We see no compelling evidence that the lack of L2s in Zevinaella is a consequence of fusion with the carinolatera (CLs), as appears to be the case in a near relative T. pentacrinarum, or of progressive reduction and potential loss, as in older specimens of Amigdoscalpellum spp. (Zevina, 1978b). However, this does not weaken the diagnosis of the new genus and, accordingly, the diagnoses for the family Scalpellidae Pilsbry, 1907 and the subfamily Arcoscalpellinae Zevina, 1978b are amended to accommodate the absence of the L2s.

An illustrated catalogue of the scalpellid barnacles (Crustacea: Cirripedia: Scalpellidae) collected during the HMS "challenger" expedition and deposited in the Natural History Museum, London.

For the first time since 1883, the "Challenger" collection of scalpellids stored in the Natural History Museum (London) and studied by Hoek, has been reviewed. It comprises 40 species now assigned to 17 genera and three subfamilies within the family Scalpellidae. A checklist of published records, type status, sources of supplementary descriptive information, updated distributions and known depth records is given. New photographs are included which may be useful for species identification and for any future systematic rearrangement of the scalpellids. Trianguloscalpellum weltnerianum (Pilsbry, 1911) is recognised as a junior subjective synonym of Trianguloscalpellum album (Hoek, 1883).