Hymedesmia baculifera

(Topsent, 1901)

Species Overview

Hymedesmia baculifera (Topsent, 1901) is an ill-known species, originally recorded from the Mediterranean, but subsequently off Roscoff. The spiculation is not very specific and life colour varies strongly in the various records (yellow, white, brown and black).

Taxonomic Description

Colour: Dark yellow or yellow-ochre (?blackish: Topsent, 1904).
Shape, size, surface and consistency: Thin crust, often on other sponges or shells; surface smooth, shiny, without projecting spicules.
Spicules: Megascleres : Tornotes are anisostrongyles with variably tylote, mucronate or elliptical heads: 150-274 x 2-4 µm; acanthostyles in a variable but single size category, spines long, recurved: 61-214 x 11-28 µm.
Microscleres : Arcuate isochelae, evenly curved, sometimes malformed or with reduced chelae: 13.5-25 µm.
Skeleton: Hymedesmoid.
Reproduction: In the Mediterranean embryos are found in July and August (Boury-Esnault, 1971)
Ecology: Encrusting shells, worm tubes and corals, mostly in deeper water, from 7 m down to 900 m.
Distribution: Mediterranean, Azores, SW Ireland, Roscoff, Arctic Atlantic.
Etymology: Baculum (Latin) = staff, referring to the tornotes.
Type specimen information: Presumably in the Muséum National d'Histoire Naturella, Paris.

Remarks

This is an ill-known species, originally recorded from the Mediterranean, but subsequently off Ireland and Roscoff. The spiculation is not very specific and life colour varies strongly in the various records (yellow, white, brown and black).
Source: Cabioch (1968), Boury-Esnault (1971).