Chalinula ramiculosa, Bispo & Willenz & Hajdu, 2022

Bispo, André, Willenz, Philippe & Hajdu, Eduardo, 2022, Diving into the unknown: fourteen new species of haplosclerid sponges (Demospongiae: Haplosclerida) revealed along the Peruvian coast (Southeastern Pacific), Zootaxa 5087 (2), pp. 201-252 : 219-221

Chalinula ramiculosa sp. nov.

( Figure 4 , Table 3 , Table 4)

Holotype. MNRJ 12889 (Vouchers: RBINS-IG 32240 -POR 12889, MHNG 85722 )— Islote , Atenas , Reserva Nacional de Paracas, Ica Region (13°49’38.71” S — 76°18’07.41” W), depth 3 m, coll. Y. Hooker, Ph. Willenz & N. Mostajo Berropsi (13/XII/2008) . Paratypes. MNRJ 12820 ( Vouchers : RBINS-IG 32240 -POR 12820, MHNG 85652 )— Isla Independencia ( Isla La Vieja) (14º16’08.20” S, 76º11’25.00” W), depth 7.0 m, coll. Y. Hooker, Ph. Willenz & F. Azevedo (09/XII/2008) ; MNRJ 12887 ( Vouchers : RBINS-IG 32240 -POR 12887, MHNG 85720 ) , MNRJ 12888 ( Vouchers : RBINS-IG 32240 -POR 12888, MHNG 85721 ) , MNRJ 12890 ( Vouchers : RBINS-IG 32240 -POR 12890, MHNG 85723 ) , MNRJ 12892 ( Vouchers : RBINS-IG 32240 -POR 12892, MHNG 85725 )— Islote , Atenas , Reserva Nacional de Paracas, Ica Region (13°49’38.71” S, 76°18’07.41” W), depth 1.6–3.3 m, coll. Y. Hooker, Ph. Willenz & N. Mostajo Berropsi (13/XII/2008) . Additional material deposited in collections. MNRJ 12891 (Vouchers: RBINS-IG 32240 -POR 12891, MHNG 85724 ) — Islote , Atenas , Reserva Nacional de Paracas, Ica Region (13°49’38.71” S, 76°18’07.41” W), depth 2.9 m, coll. Y. Hooker, Ph. Willenz & N. Mostajo Berropsi, (13/XII/2008) .

Diagnosis. Only Chalinula in the Eastern Pacific with the combination of a massive habit and a dense mass of short, bifurcating and anastomosing branches, colour alive beige to pinkish beige, and an isotropic, unispicular skeleton of oxeas 93–157 µm long.

Description ( Fig. 4A, B ). Massive, irregularly outlined (MNRJ 12820), or a dense mass of short, irregular, often bifurcating or anastomosing branches widening apically (MNRJ 12887, 12888, 12889, 12892). Specimens reached 15 cm in largest diameter, and 5 cm in thickness. Surface smooth, albeit somewhat irregular, with tangential, longitudinal subectosomal strands, and a slight reticulation, both visible upon zooming in on underwater in situ images. Oscula, 0.8–4.0 mm diam., common, circular, mostly located at the base of branches, slightly elevated on short volcaniform projections. Consistency soft, compressible. Colour in life beige to pinkish-beige, darkening to purplish-brown after exposure to the air.

Skeleton ( Fig. 4C, D ). No specialized ectosomal skeleton, but loose, even abundant tangential oxeas may be spread at the surface (holotype). Choanosomal architecture a confused unispicular, isotropic reticulation, with only seldom recognizable loose primary tracts, and even fewer connecting lines, two spicules long. Spongin very scarce, only at the nodes of the reticulation.

Spicules ( Fig. 4E, F ). Oxeas, fusiform, straight, or more frequently subtly bent at centre, sharp acerate points, 81– 123 –150 x 1.3– 5. 5–9.0 µm. ( Table 4)

Ecology. Attached to rock, or epibiontic on bivalves or Codium -like algae in the very shallow subtidal (3–7 m depth, MNRJ 12892). The mass of sponge and algae branches houses ophiuroids and crabs, and can be markedly overlaid by fine sediment. Water temperature during collection was 13°C for MNRJ 12820 and 16°C for 12892.

Distribution ( Fig. 3B ). Only known from Paracas and Isla La Vieja (Ica Region), in Peru.

Etymology. The epithet “ ramiculosa ” is used as a noun in apposition derived from the diminutive form of the L. ramus, pl. rami (L. ramusculus = small branch + L. - osus = in abundance), and refers to the presence of short and abundant branches in this species.

Remarks. The main pattern observed in C. ramiculosa sp nov. skeleton is a unispicular, isotropic reticulation, almost without primary and secondary lines. However, there are some areas where an anisotropic reticulation is apparent, with secondary lines more than one spicule long, bringing the new species close to Chalinula . As already pointed before in the Remarks section for Chalinula , such a variation in the skeleton is present in several species of this genus.

The only additional Chalinula in the Peruvian coast is C. chelysa sp. nov. Howewer, the massive shape and the presence of abundant, small, irregular-anastomosed branches in C. ramiculosa sp. nov. set both species apart ( Table 3 ). Another Eastern Pacific Chalinidae resembling somehow the habit of C. ramiculosa sp. nov. is H. (Rh.) enamela de Laubenfels, 1930 . Even so, both are readily distinguished based on the mainly isotropic and unispicular skeleton with scarce spongin of the new species, in contrast to the stout reticulation of multispicular primary lines cored by 6–8 spicules, and rich in spongin. Remaining Eastern Pacific Chalinidae are all easily distinguished on the basis of tabulated comparative data shown in Table 3 .

Figures

FIGURE 3. Map showing the geographic distribution of Peruvian haplosclerids. A, distribution of Chalinula chelysa sp. nov.; B, distribution of Chalinula ramiculosa sp. nov. and Haliclona (G.) concreta sp nov.; C, distribution of H. (Halich.) arequipaensis sp. nov., H. (Halich.) multiosculata sp. nov. and H. (Halich.) marcoriosi sp. nov.; D, distribution of H. (Halich.) paracas sp. nov., H. (Halich.) pellucida sp. nov. and (Reniera) parvuloxea sp. nov.; E, distribution of H. (Rhizoniera) spp. nov.; F, distribution of Niphates ruthecitae sp. nov. and Pachychalina lupusapia sp. nov.

FIGURE 4. Chalinula ramiculosa sp. nov. A, paratype alive (MNRJ 12892); B, holotype alive (MNRJ 12889); C, skeletal architecture in transverse ground section (MNRJ 12820, paratype); D, skeletal architecture in transverse ground section (MNRJ 12889, holotype); E–F, oxeas (MNRJ 12889, holotype). Scale bars: A, 5 cm; B, 1 cm; C–D, 500 µm; E–F, 20 µm. White arrows indicate secondary lines with two or more spicules long.