Hymeraphia verticillata

Bowerbank, 1866

Species Overview

Hymeraphia verticillata Bowerbank, 1866 is an encrusting lemon yellow sponge with a granular surface and firm consistency.

Taxonomic Description

Colour: Lemon yellow (Descatoire, 1966)
Shape, size, surface and consistency: Thin encrustations, lateral size up to 3.5 x 2 cm. Surface has granular aspect and consistency is firm.
Spicules: (Hymeraphia verticillata spics) Tylostyles, with long, rounded tyle: 1900-2800 x 20-25 µm; centrotylote oxeas: 490-1600 x 12-25 µm; verticillately spined oxeas / strongyles: 90-120 x 4-5 µm; growth stages of the latter may be smoothly polytylote.
Skeleton: Ectosomal : a dense mass of verticillate oxeas/strongyles. Choanosomal : single long tylostyles erect on the substrate, heads downward, pointed ends protruding beyond the surface; bundles of centrotylote oxeas surround these tylostyles.
Ecology: On pebbles, from 50 m downwards to 1000 m.
Distribution: Roscoff, SW Ireland, Shetlands, Orkney, Faroes, Norway.
Etymology: The name refers to the whorls of spines on the oxeas/strongyles.
Type specimen information: The type is in the Natural History Museum, London.

Remarks

The only species with similar granular appearance and spiculation is Halicnemia patera . This is softer in consistency. The microxeas of that species are angularly bent and the spines are not in verticils.
Source: Descatoire, 1966