Crateromorpha (Neopsacas) obi, 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 : 64-66

Crateromorpha (Neopsacas) obi , sp. nov. ( Fig. 8 , 9 )

Description

Body: The body is severly damaged, but it may be assumed that its general shape is similar to that of the other species of the genus. Peduncle is thin, 0.8 mm in diameter 65 mm long (the basal part is broken). The upper part of the body is missing, but a remnant attached to the peduncle is 20 mm long and 22 mm in diameter.

Spicules: Choanosomal spicules are diactins, 1.6–4.6/ 0.007–0.011 mm, they are usually rough with rough clavate outer ends and with a widening in the middle. The spicules of the peduncle are diactins, 0.007–0.076 mm in diameter, fused by numerous synapticula junctions.

Hypodermal and probably also hypoatrial spicules are pentactins and rarely hexactins (only hypodermal ones observed) with spiny rays, the spines are more numerous and larger close to the spicule centre, the outer ends are usually clavate and spiny. The tangential rays of hypodermal and hypoatrial pentactins and hexactins are 0.213–0.403 mm long (n=27; avg= 0.310mm; std= 0.063mm), ray directed inside the body is 0.152–0.699 mm long (n=14; avg= 0.464mm; std= 0.156mm), the ray directed outside the body in hexactins is 0.046–0.152 mm long (n=5; avg= 0.096mm; std= 0.039mm), their diameter is 0.015–0.046 mm. Dermalia or atrialia are rough pentactins, sometimes with short ray directed inside the body, these spicules have rounded outer ends, and as in most other species of this genus they are very rare. The tangential rays of dermal or atrial pentactins are 0.084–0.144 mm long (n=8; avg= 0.112mm; std= 0.019mm), the ray directed inside the body is 0.061– 0.110 mm long (n=5; avg= 0.089mm; std= 0.023mm), diameter is 0.005–0.009 mm.

The only type of microscleres found are drepanocomes with 8–12 secondary rays. The diameter of the drepanocome is 0.032–0.050 mm (n=25; avg= 0.043mm; std= 0.005mm), the diameter of the primary rosette is 0.011–0.016 mm (n=25; avg= 0.013mm; std= 0.002mm).

Figures

FIGURE 8. Crateromorpha (Neopsacas) obi sp. nov., holotype, side view. Scale 10 mm.

FIGURE 9. Crateromorpha (Neopsacas) obi, sp. nov., spicules: A – B, dermal or atrial pentactins. B, pentactin with rudimental ray directed inside the body. C, hypodermal or hypoatrial pentactin. D, hypodermal or hypoatrial hexactin. E – F, parts of choanosomal diactin. G, drepanocome. H, secondary ray of drepanocome.