Marianina rosea (Pruvot-Fol, 1930)

Location: Yaene, Hachijo Island, Tokyo, Japan
Date: 2016/07/13
Length: 8mm
Depth: 15.0m
Water temperature: 26.1℃

Description

A very small tritoniid. According to the original description, the body shape resembles that of Duvaucelia Risso. The dorsal appendages are not branched as in typical tritoniids; instead, two small flattened, horizontal, divergent leaves are borne on a common stalk, with four such stalks arranged in pairs on each side of the back (a character also found in Duvaucelia). In life the body is rose-carmine. The lateral processes and the four digitations of the oral veil are pure white, as are the rhinophore sheath margins. The slightly branched apex of the rhinophores is pale yellow.

Distribution

Type locality: Kuto Bay, Île des Pins, New Caledonia, based on specimens collected by Mme A. Pruvot-Fol in 1929. The species has subsequently been recorded across the Indo-West Pacific and South Atlantic, with reports from South Africa, Madagascar, Australia, New Caledonia, Papua New Guinea, the Philippines, the Mariana Islands, and Japan.

Etymology

The original description (Pruvot-Fol, 1930) explicitly states for the genus: "Dédié à ma fille Marianne" (dedicated to my daughter Marianne). The genus name Mariana therefore honours the author's daughter. The specific epithet rosea is Latin for "rose-coloured, rosy", in reference to the carmine-rose ground colour ("rose carminé") of the body.

Remarks

In the original description Pruvot-Fol erected the new genus Mariana in the family Tritoniidae. Mariana was preoccupied in zoological nomenclature, and Pruvot-Fol herself subsequently proposed the replacement name Marianina (the parentheses in the author citation reflect this replacement of the generic name). The Japanese vernacular name "ナンヨウウミウシ" ("Nanyō [South Sea] sea slug") refers to the species' South Pacific tropical-subtropical distribution including the New Caledonian type locality.