Crateromorpha (Neopsacas) krinovi krinovi, Menshenina, Larisa L., Tabachnick, Konstantin R. & Janussen, Dorte, 2007

Menshenina, Larisa L., Tabachnick, Konstantin R. & Janussen, Dorte, 2007, Revision of the subgenus Neopsacas (Hexactinellida, Rossellidae, Crateromorpha) with the description of new species and subspecies, Zootaxa 1463, pp. 55-68 : 60-62

Crateromorpha (Neopsacas) krinovi krinovi , sp. nov., ssp. nov. ( Fig. 3 , 4 ; Tab. 2 )

Material examined

Holotype: IORAS 5/2/3176—R.V. ‘Professor Logatchev’,16, Ashadze-1, dredge, 2005, close to the hydrotermal field, 12° 58.4’ N 44° 51.8’ W (Mid-Atlantic Ridge), depth 4100–4200 m.

Description

Body: Overall shape is the same as of C. (Neopsacas) variens . The body is 80 mm long, about 50 mm in diameter, the walls are only 1–3 mm in thickness, the atrial cavity is large; peduncle is tubular, 60 mm long (broken), 3–5 mm in diameter.

Spicules: Choanosomal spicules are diactins, rarely tauactins and stauractins. The diactins are 1.4–2.6/ 0.008–0.024 mm, they have a widening in the middle and rounded, smooth outer ends. The diactins of the peduncle are 0.015–0.027 mm in diameter, connected to each other by numerous synapticula junctions. Hypodermalia are pentactins with spines situated close to the spicule centre, the outer ends are conically pointed and spiny. Tangential rays of hypodermal pentactins are 0.16–0.38 mm long, proximal ray is 0.72–1.56 mm long, the diameter of these rays is 0.02–0.05 mm. Dermalia and atrialia are pentactins and diactins, rarely other derivatives of pentactins with reduced rays. These spicules have rough rays and rounded outer ends. Dermal pentactins have tangential rays 0.022–0.170 mm long, the proximal ray is usually short, 0.026–0.081 mm long, the diameter of these rays is 0.006–0.010 mm. Dermal diactins have rays of 0.026–0.093/ 0.002– 0.005 mm and usually possess four rudimental tubercles in the centre. Atrial pentactins have tangential rays 0.041–0.175 mm long and distal ray about 0.052 mm long, their diameter is about 0.004 mm. Atrial diactins have rays 0.032–0.072/ 0.004 mm.

Microscleres are represented by a succession of spiny discoidal spicules varying from discohexactins to discodiactins (“amphidiscs”), their rays are 0.027–0.088/ 0.002–0.005 mm. Among these spicules discopentactins (39%) and discohexactins (36%) prevail; the others are discostauractins and discotetractins (16%), discotauactins (8%) and discodiactins (1%). In pentactins the four rays forming a cross are usually slightly bent away from the cental ray.

Etymology

The species is named in the honour of geologist Dr. D. Krinov, who collected this specimen.

Figures

FIGURE 3. Crateromorpha (Neopsacas) krinovi krinovi sp. nov., ssp. nov. A, holotype, side view. Scale 20 mm. B, dermal discohexactin. C, atrial discohexactins. Scales 10 µm.

FIGURE 4. Crateromorpha (Neopsacas) krinovi krinovi sp. nov., ssp. nov., spicules: A – B, dermal pentactins. C – D, dermal diactins. E, hypodermal pentactin. F, choanosomal stauractin. G, choanosomal diactin. H, discohexactin. I – J, discopentactins. K, discostauractin. L, discodiactin.