Forcepia (Forcepia) fabricans (Schmidt, 1874) is a massive crust, sometimes partly grwoing erect, with limp oscular papillae. The surface is slightly shaggy. Life colour is unknown. Consistency is somewhat elastic. It is an Arctic deep water species.
Colour: Live colour unknown, in alcohol it is greyish white or yellowish white, dried it is brownish.
Shape, size, surface and consistency: Massive, with papillate surface (Forcepia fabricans Koltun); easily damaged. Size up to 6 cm high. Surface somewhat shaggy, with a thin dermal membrane. Papillae are scattered, about 1.5 mm high, either closed or with an oscular opening. In some specimens pores are united into elongated elevated systems. Consistency rather loose, somewhat elastic.
Spicules: (Forcepia fabricans spics) Megascleres: Ectosomal tylotes, straight, with only slightly swollen ends: 310-450 x 7-12 µm; styles, curved: 530-715 x 13-21 µm.
Microscleres: Arcuate isochelae, large: 42-57 µm; forceps, spined, with equal length legs, which end in a distinct spined knob, in two size categories: 60-77 x 3 µm and 25-34 x 1 µm; sigmas, large: 120-140 x 7 µm.
Skeleton: The ectosomal skeleton consists of bundles of erect spicules projecting from the skeleton below; inbetween these bundles there are only microscleres. In the papillae the spicules are tangential. The choanosomal skeleton is plumose and consists of a rather irregular network of spicule tracts, 3-6 spicules in cross section, bound by only a little spongin; no clearly developed interconnecting tracts. Single spicules are scattered.
Reproduction: Embryos of 350 µm, some with small chelae of only 30-35 µm were observed in deep-water specimens off Iceland.
Ecology: Deep-water, 90-685 m.
Distribution: Arctic (N of North Cape, Spitsbergen, Iceland, East Greenland, Bering Sea)
Etymology: fabricans (Latin) = forging, presumably referring to the horseshoe-shape (made in forges) of the microscleres.
Type specimen information: No type in the Natural History Museum, London.
This species differs from F. (F.) forcipis in the much smaller size of the largest category of forcipes, and from F. (F.) psammophila a.o. in the equal length of the forceps legs. Most of the related Forcepia species live at greater depths, but since this species is known from 90 m it is included here.
Source: Lundbeck, 1905.