Ute gladiata

Borojevic, 1967

Species Overview

Ute gladiata Borojevic, 1967 forms whitish, solitary tubes with a smooth surface and a "naked" oscule. It is about 2 cm high. It is similar to Aphroceras ensata and can only be distinguished from it on the basis of subtle differences in arrangement of the ectosomal triactines and in histological sections. It is a rare species so far known only from the West coast of France.

Taxonomic Description

Colour: White.
Shape, size, surface and consistency: Solitary tubes, small, up to 2 cm high 3 mm in diameter, with a glistening smooth surface. Oscule apical, "naked" (without a fringe of stiff spicules). Consistency fragile.
Spicules: (Ute gladiata spics) Calcareous. Choanosomal triactines, almost equiangular, unpaired ray: 100-160 x 9-10 µm, paired rays: 70-120 x 10 µm; subatrial triactines, quite sagittal, unpaired ray 100-160 x 9-10 µm, paired rays: 60-100 x 9-10 µm; atrial triactines, unpaired ray long and thin, thickening in the distal half: 150-400 x 2-7 µm, paired rays: 50-100 x 10-12 µm.
Choanosomal tetractines: like the triactines, apical ray 30 µm; atrial tetractines, like the triactines, with a fourth ray shaped like a sabre: up to 450 x 25 µm; triactines and tetractines from the oscular rim like the atrial spicules.
Ectosomal long oxeas, almost straight, one of the points is lanceolate: up to 1000 x 70 µm; microdiactines, the distal end shaped like a bayonet: 60-120 x 1-2 µm.
Skeleton: Syconoid structure, but irregular and the radial tubes are branched at the distal end. Subdermal lacunae are sometimes present and the inhalant canals are very narrow. The ectosomal skeleton consists exclusively of long oxeas. They are arranged in 1 or 2 layers, strictly parallel, and they form a well-delimited crust; the oxeas never enter the choanosomal skeleton; there are no ectosomal triactines. The ectosomal skeleton also contains microdiactines arranged perpendicular to the long oxeas. The choanosomal skeleton is rather irregular especially in the internal parts. A row of subatrial triactines separates the atrial skeleton from the rows of triactines which support the radial tubes. The triactines of the choanosome may sometimes develop a fourth incipient ray. The atrial skeleton is thin, regularly pierced by the apopyles of the radial tubes and constructed by sagittal triactines and tetractines with very long unpaired ray.
Ecology: On hard substrate in the Axinella zone down to 55-60 m.
Distribution: Roscoff, Iles des Glénans.
Etymology: Gladius (Latin) = sword, referring to the sword-like shape.
Type specimen information: The type is in the Muséum National d'Histoire Naturelle, Paris.

Remarks

This species is similar in most respects to Aphroceras ensata , but differs in lacking any ectosomal or subectosomal layer of triactines, found normally in A . ensata along with the long oxeas. Also the latter never penetrate the choanosome as is most often the case in A . ensata .
Source: Borojevic, 1967