Pozziella cerilla Díaz-Agras, 2008, sp. nov.
Creators: name: Díaz-Agras, Guillermo
Publisher: name: Zenodo
Year: 2008
Subjects: Biodiversity
Taxonomy
Animalia
Porifera
Demospongiae
Poecilosclerida
Hamacanthidae
Pozziella
Pozziella cerilla

description: Pozziella cerilla sp. nov.
(Figs. 3, 6–9, 19)
Examined material: Wet holotype ZMB Por. 12645 (preparations at O.M. deposited at ZMB). Type locality: Cocos Ridge; from 03º 27.60 N, 090º 37.00 W to 03º 27.56 N, 090º 36.63 W; depth 1224–1458 m; station 32; campaign SO 144–3a.
Description
Habitus: Incrusting, thin layer of 2–3 mm thickness, covering surface of 20 mm x 9 mm (Fig. 6 A, B). Yellowish white colour in alcohol. No oscula visible. Flexible and fragile consistency with rough texture. Base of specimen with sediment, small fragments from other sponges and remains of malacostracan crustacean inside a fold.
Spicules
Megascleres: Small, smooth, rectilinear and fusiform styles II, pointed ends slightly rounded; rounded end semispherical (Fig. 7 A; 8 A–C). Some styles with enlarged axial canal. Size: 300–450 µm in length (M. ± S.D., 389.7 ± 37.02 µm) and 7.5–12.5 µm in mid­region (M. ± S.D., 10.9 ± 1.42 µm), diameter decreasing towards rounded end to 2.5–7.5 µm (M. ± S.D., 5.3 ± 1.81 µm) (form index: 0.028).
Straight exotyles (Fig. 7 B; 8 D) with rounded end (Fig. 8 F) opposite the tyle. Latter in claviform shape, with irregular and rough surface (Fig. 8 E). Irregularities continue along shaft for ¼ of its length, lower ¾ of shaft smooth (Fig. 8 D–F). Shaft with uniform diameter. Exotyle size: length 125–165 µm (M. ± S.D., 147.4 ± 10.84 µm), width 2.5–5 µm (M. ± S.D., 4.6 ± 0.9 µm) and tyle width 7.5–12.5 µm (M. ± S.D., 9.6 ± 1.72 µm) (form index 0.065).
Microscleres: Large cyrtancistras I with semilanceolate ends (Fig. 8 H, I); spicule with very obtuse angle in mid­region (Fig. 7 C; 8 G). Some cyrtancistras with two denticles on lanceolate hooks (Fig. 8 H). Cyrtancistra size: height 490–640 µm (M. ± S.D., 593.2 ± 35.91 µm) and width 20–25 µm (M. ± S.D., 21.9 ± 1.66 µm) (form index: 0.41). Small, thick and strong type II sigmas, generally C­shaped (Fig. 7 D; 8 J): height 14– 18 µm (M. ± S.D., 16.44 ± 1.33 µm) and width 1µm (M. ± S.D., 1.0 ± 0.0 µm) (form index: 0.59).
Skeleton
Skeletal arrangement: Choanosomic plurispicular fascicula of styles arranged in bunches near ectosome (Fig. 9). Ectosome consisting of irregularly arranged tangential styles with free exotyles or exotyles forming hispid bunches of 4 or 5, with tyles pointing out. Cyrtancistras situated in ectosome underneath stylar layer. Very abundant sigmas arranged as ectosomal crust just beneath tangential styles.
Distribution: Galápagos archipelago, Cocos Ridge; from 03º 27.60 N, 090º 37.00 W to 03º 27.56 N, 090º 36.63 W; depth 1224–1458 m.
Derivatio nominis: The name of this species derives from the Spanish word for match, ‘cerilla’, as the shape of its exotyles resembles a match.
Discussion: Pozziella cerilla sp. nov. is characterized by having exotyles with a claviform tyle, which differs from P. clavisepta, P. a p e r t a and P. neuhausi sp. nov., in which the tyles have a spherical shape. The shape of the exotylar tyle in P. lueteri sp. nov. is similar to that in P. cerilla sp. nov. However, the tylar irregularities of P. lueteri sp. nov. only occur on the tyle itself, whereas in P. cerilla sp. nov. they extend down to ¼ of the spicule shaft. P. cerilla sp. nov. additionally displays longer and thinner exotyles than P. lueteri sp. nov., as the form index of each species shows: 0.065 in P. cerilla sp. nov. and 0.154 in P. l u e t e r i sp. nov. The exotyles in P. cerilla sp. nov. are arranged loosely in the ectosome or form bundles of 4 or 5 exotyles with the tyle pointing out. This arrangement is similar to that observed for P. neuhausi sp. nov., but in the latter the exotyles never form bundles. In the remaining species they create a uniform layer in the ectosome, with the tyles pointing out.
Pozziella cerilla sp. nov. differs from P. c l a v i s e p t a by having only one type of sigma and cyrtancistras with an angular curvature. It differs from P. aperta because the latter has two types of cyrtancistras. Moreover, the largest cyrtancistras of P. aperta do not have the angulation of those of P. cerilla sp. nov.
P. neuhausi sp. nov. and P. lueteri sp. nov. have only one type of cyrtancistras and sigmas, similar to P. cerilla sp. nov. However, P. cerilla sp. nov. differs from P. lueteri sp. nov. by having angular cyrtancistras, and it differs from P. neuhausi sp. nov. by having cyrtancistras with a more pronounced angulation. In P. cerilla sp. nov. the cyrtancistras are situated in the ectosome under the tyles, whereas in P. neuhausi sp. nov. they are at the base of the sponge. The above characters distinguish P. cerilla sp. nov. from the other Poziella spp. and justify the creation of the new species.
description: Published as part of Díaz-Agras, Guillermo, 2008, Revision of the genus Pozziella (Porifera: Poecilosclerida) with description of three new species from the eastern Pacific *, pp. 69-94 in Zootaxa 1866 on pages 77-81, DOI: 10.5281/zenodo.183749