Hymedesmia (Hymedesmia) santarositae Salani &amp; Willenz &amp; Fernandez &amp; Hajdu 2022, sp. nov.
Creators: name: Salani, Sula
name: Willenz, Philippe
name: Fernandez, Julio C. C.
name: Hajdu, Eduardo
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Porifera
Demospongiae
Poecilosclerida
Hymedesmiidae
Hymedesmia
Hymedesmia santarositae

description: <i>Hymedesmia</i> (<i>Hymedesmia</i>) <i>santarositae</i> sp. nov. (Figure 2; Table 1) <b>Material examined.</b> <b>Holotype</b> &amp;horbar; MNRJ 12843 (Vouchers: RBINS-IG 32240 - POR12843, MHNG 85676), Isla Santa Rosa 2, Reserva Nacional de Paracas, Ica Region (14.31950S, 76.16456W), depth 8 m, coll. F. Azevedo, Y. Hooker &amp; Ph. Willenz (10/XII/2008). <b>Diagnosis.</b> <i>Hymedesmia</i> (<i>H.</i>) with arcuate chelae, microstrongyles and sigmas. <b>Description (Figs 2A–B).</b> Thinly encrusting sponge (≈ 15.2 cm 2), less than 1 mm thick (0.2 to 0.8 mm, Fig. 2A). Consistency very soft and fragile. Surface smooth, with visible oval to circular areolated porefields (3.4 x 1.3 cm largest and smallest diameters) and subectosomal canals, oscula visible <i>in situ</i> (≈ 0.2–0.4 cm). (Fig. 2B). Color brownish beige in life (<i>in situ</i>) and beige transparent when preserved in ethanol. <b>Skeleton (Figs 2C–D).</b> Ectosomal skeleton with ectosomal strongyles to subtylotes forming longitudinal bundles from surface to substrate (Fig. 2C). Subectosomal and choanosomal skeletons overlapping, composed of typical hymedesmioid structure, consisting of a basal layer of spongin, with acanthostyles I and II erect on the substrate (Fig. 2C). Isochelae, sigmas and microstrongyles (Fig. 2D) appear scattered in the sponge, and some acanthostyles I lay parallel to, or flat on the substrate. <b>Spicules (Figs 2E–N; Table 1)</b>. Ectosomal diactines: strongyles to subtylotes, smooth, straight (Fig. 2G) with rounded ends (Fig. 2 H –I), 129– <i>153.1</i> –187 (± 16.3) × 3.6– <i>4.5</i> –5.2 (± 0.4) × 3.8–5.0 µm (tyle, N = 3) (Figs 2G–I). Choanosomal acanthostyles I (Fig. 2E): larger, apex tapering gradually, acerate tip, base occasionally with a more or less distinct swelling; shaft straight to slightly curved, spines slightly curved or conical and spread from base to mid shaft, 158– <i>206.2</i> –270 (± 31.9) × 5.4– <i>8.3</i> –11.1 (± 1.9) µm. Choanosomal acanthostyles II (Fig. 2F).: straight, tapering gradually, acerate tip and round base, spines spread all along the spicule, curved, those at the base bent as hooks, 76– <i>83.8</i> –96 (± 5.0) × 4.9– <i>6.1</i> –7.9 (± 0.7) µm. Arcuate isochelae (Figs 2M–N): one free spatulate ala and two lateral alae semi-fused with the shaft; shaft characteristically curved, bow-shaped, 17– <i>19.1</i> –21 (± 1.1) × 2.4– <i>3.7</i> –4.8 µm. Sigmas (Fig. 2J): C shape, tips straight and acerate, 27– <i>29.4</i> –33 (± 2.2) × 2.9– <i>3.2</i> –3.9 (± 0.3) µm. Microstrongyles (Figs 2K–L): smooth, curved and robust, rounded ends, 24– <i>28.6</i> –34 (± 2.7) × 2.3– <i>3.4</i> –4.6 (± 0.5) µm. <b>Ecology.</b> Specimen collected from a nearly vertical rocky substratum, at 8m depth. Growing over tubes of polychaetes. <b>Distribution.</b> Known only from its type locality, Isla Santa Rosa. <b>Etymology.</b> The species name, “ <i>santarositae</i> ” refers to its type locality also called Isla Santa Rosa. <b>Remarks.</b> <i>Hymedesmia</i> (<i>H.</i>) <i>santarositae</i> <b>sp. nov.</b> differs from all other <i>Hymedesmia</i> species (table 2) by the presence of microstrongyles as microscleres, in addition to arcuate chelae and sigmas.
description: Published as part of <i>Salani, Sula, Willenz, Philippe, Fernandez, Julio C. C. &amp; Hajdu, Eduardo, 2022, Three new Hymedesmia Bowerbank, 1864 (Demospongiae, Poecilosclerida Hymedesmiidae) from the Southeast Pacific (Peru and Chile), pp. 217-240 in Zootaxa 5165 (2)</i> on pages 219-221, DOI: 10.11646/zootaxa.5165.2.4, http://zenodo.org/record/6831761