Clathria (Thalysias) chelosigmoidea, Zea, Sven, Rodríguez, Angélica & Martínez, Ana María, 2014

Zea, Sven, Rodríguez, Angélica & Martínez, Ana María, 2014, Taxonomy of Clathria (Thalysias) (Demospongiae: Poecilosclerida: Microcionidae) from the Colombian Caribbean, with description of three new species, Zootaxa 3835 (4), pp. 401-436 : 425-427

Clathria (Thalysias) chelosigmoidea new species

Figures 14 , 15 , plate 3 figures A, B

Clathriidae sp. 1; Zea 1993: 88 (ecology).

Material examined. Santa Marta: Holotype: ICN-MHN(Po) 261, Bahía de Santa Marta, El Morro, rocky shore, on crustose coralline algae on metamorphic, overhanging rock, 8–9 m, coll. S. Zea, 10 Feb. 1994. Paratypes, INV- POR 1253 (among gorgonian bases 4.5 m, 10 Feb. 1994), INV-POR 1254 (overhanging rock, 7–8.5 m, 29 Feb. 1988), INV-POR 1255 (4.5–6 m, 6–7 Apr. 1988), Bahía de Santa Marta, El Morro, coll. S. Zea.

Shape, color and consistency. Indistinguishable in the field in shape, color and consistency from Clathria (Thalysias) sulfocleistochela n. sp. Briefly, very thin encrustations with a slightly conspicuous star-shaped vein pattern of the canal system and oscules. Ectosome transparent; choanosome with various shades of greenish, sulfur yellow, dark orange and cinnamon. Consistency soft.

Skeleton. Ectosome as a thin pinacoderm supported by sparse, rather open brushes of small auxiliary subtylostyles. In the choanosome there are basal principal styles in groups of 1–3, arising each 90–200 µm from slight elevations of a basal spongin sheet, surrounded by echinating accessory acanthostyles; areas between groups with a few acanthostyles. Ectosomal brushes of subtylostyles rise from the tips of the styles; larger subtylostyles are paratangentially located below the ectosome or are horizontally located among styles in the basal choanosome; chelae abundant everywhere. Spicules (Table 1): (1) Long, slightly curved principal styles, with prominent heads with low and wide spines, 157– 256.5 –409 µm by 5,7– 9.5 –13.8 µm. (2) Straight auxiliary subtylostyles with very small heads, usually not spined, a wide axial canal, and blunt, telescopic ends; the shaft may be spined or rugose near the base; the two size categories are difficult to separate, but the smaller are usually ectosomal; large ones, 161– 187.2 –228 µm by 1.0– 2.4 –4.3 µm, smaller ones, 104– 134.0 –143 µm by 1.0– 1.4 –2.4 µm. (3) Echinating accessory acanthostyles, slender, heads slightly prominent, spined; shaft straight to slightly curved, sparsely spined, last apical quarter smooth, narrow, slightly telescopic, 76– 83.3 –103 µm by 3.7– 4.5 –5.2 µm. (4) Sigmoid palmate chelae, with reduced alae, 13.2–15.0 µm.

Type locality. El Morro, Bay of Santa Marta, Colombia, Caribbean Sea (11° 14’ 57” N, 74° 13’ 49” W).

Distribution and ecology. Santa Marta, Colombia. It inhabits rocky shores, on inclined to overhanging substrata, 4–10 m in depth.

Etymology. Adjective derived from the unusually shaped palmate sigmoid chelae.

Remarks. See remarks on similarities and differences with C (T.) sulfocleistochela n. sp. The sigmoid chelae are present in other species of the subgenus from Australia [e.g., C. (T.) hesperia Hooper, 1996 , C. (T.) michaelseni (Hentschel, 1911) ], and other poecilosclerids (see Hooper 1996).

Figures

FIGURE 14. Clathria (Thalysias) chelosigmoidea n. sp. Schematic drawing of spicule types (A) and skeleton (B). (a) Basal principal styles, (b) choanosomal auxiliary subtylostyle, (c) ectosomal auxiliary subtylostyle, (d) echinating accessory acanthostyle, (e) sigmoid palmate chela, (f) section perpendicular to the surface.

FIGURE 15. Clathria (Thalysias) chelosigmoidea n. sp. SEM micrographs of spicules of a specimen from Santa Marta. (a) Choanosomal principal styles, (b) ectosomal auxiliary subtylostyle (the larger choanosomal ones were scarce in the SEM sample), (c) echinating accessory acanthostyles, (d) sigmoid palmate chelae.