Hymedesmia (Hymedesmia) santarositae, Salani & Willenz & Fernandez & Hajdu, 2022

Salani, Sula, Willenz, Philippe, Fernandez, Julio C. C. & Hajdu, Eduardo, 2022, Three new Hymedesmia Bowerbank, 1864 (Demospongiae, Poecilosclerida Hymedesmiidae) from the Southeast Pacific (Peru and Chile), Zootaxa 5165 (2), pp. 217-240 : 219-221

publication ID

https://doi.org/ 10.11646/zootaxa.5165.2.4

publication LSID

lsid:zoobank.org:pub:B0D96EEA-B3FA-4607-8C28-4A19B3027BBF

DOI

https://doi.org/10.5281/zenodo.6831763

persistent identifier

https://treatment.plazi.org/id/03F487E0-FFBF-9B58-21FA-F8A9CD56D355

treatment provided by

Plazi

scientific name

Hymedesmia (Hymedesmia) santarositae
status

sp. nov.

Hymedesmia (Hymedesmia) santarositae View in CoL sp. nov.

( Figure 2 View FIGURE 2 ; Table 1 View TABLE 1 )

Material examined. Holotype ― MNRJ 12843 View Materials (Vouchers: RBINS-IG 32240 -POR12843, MHNG 85676 View Materials ), Isla Santa Rosa 2, Reserva Nacional de Paracas, Ica Region (14.31950S, 76.16456W), depth 8 m, coll. F. Azevedo, Y. Hooker & Ph. Willenz (10/XII/2008). GoogleMaps

Diagnosis. Hymedesmia (H.) with arcuate chelae, microstrongyles and sigmas.

Description ( Figs 2A–B View FIGURE 2 ). Thinly encrusting sponge (≈ 15.2 cm 2), less than 1 mm thick (0.2 to 0.8 mm, Fig. 2A View FIGURE 2 ). 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 in situ (≈ 0.2–0.4 cm). ( Fig. 2B View FIGURE 2 ). Color brownish beige in life (in situ) and beige transparent when preserved in ethanol.

Skeleton ( Figs 2C–D View FIGURE 2 ). Ectosomal skeleton with ectosomal strongyles to subtylotes forming longitudinal bundles from surface to substrate ( Fig. 2C View FIGURE 2 ). 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 View FIGURE 2 ). Isochelae, sigmas and microstrongyles ( Fig. 2D View FIGURE 2 ) appear scattered in the sponge, and some acanthostyles I lay parallel to, or flat on the substrate.

Spicules ( Figs 2E–N View FIGURE 2 ; Table 1 View TABLE 1 ). Ectosomal diactines: strongyles to subtylotes, smooth, straight ( Fig. 2G View FIGURE 2 ) with rounded ends ( Fig. 2 H –I View FIGURE 2 ), 129– 153.1 –187 (± 16.3) × 3.6– 4.5 –5.2 (± 0.4) × 3.8–5.0 µm (tyle, N = 3) ( Figs 2G–I View FIGURE 2 ). Choanosomal acanthostyles I ( Fig. 2E View FIGURE 2 ): 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– 206.2 –270 (± 31.9) × 5.4– 8.3 –11.1 (± 1.9) µm. Choanosomal acanthostyles II ( Fig. 2F View FIGURE 2 ).: straight, tapering gradually, acerate tip and round base, spines spread all along the spicule, curved, those at the base bent as hooks, 76– 83.8 –96 (± 5.0) × 4.9– 6.1 –7.9 (± 0.7) µm. Arcuate isochelae ( Figs 2M–N View FIGURE 2 ): one free spatulate ala and two lateral alae semi-fused with the shaft; shaft characteristically curved, bow-shaped, 17– 19.1 –21 (± 1.1) × 2.4– 3.7 –4.8 µm. Sigmas ( Fig. 2J View FIGURE 2 ): C shape, tips straight and acerate, 27– 29.4 –33 (± 2.2) × 2.9– 3.2 –3.9 (± 0.3) µm. Microstrongyles ( Figs 2K–L View FIGURE 2 ): smooth, curved and robust, rounded ends, 24– 28.6 –34 (± 2.7) × 2.3– 3.4 –4.6 (± 0.5) µm.

Ecology. Specimen collected from a nearly vertical rocky substratum, at 8m depth. Growing over tubes of polychaetes.

Distribution. Known only from its type locality, Isla Santa Rosa.

Etymology. The species name, “ santarositae ” refers to its type locality also called Isla Santa Rosa.

Remarks. Hymedesmia (H.) santarositae sp. nov. differs from all other Hymedesmia species (table 2) by the presence of microstrongyles as microscleres, in addition to arcuate chelae and sigmas.

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