Hymedesmia (Hymedesmia) humboldti, 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 : 224

Hymedesmia (Hymedesmia) humboldti sp. nov.

( Figure 5 ; Table 1 )

Material examined. Holotype ― MNRJ 12078 (Vouchers: RBINS – IG 32240 –POR 12078, MHNG 85520 ), Punta Coles , Ilo, Moquega Region, Peru (17.7S, 71.3808W), depth 13 m, coll. Y. Hooker, Ph. Willenz & M. Rios (06/ XI/2008) . Paratype ― MNRJ 12144 (Vouchers: RBINS – IG 32240 –POR 12144, MHNG 85587 ) , Matarani , Bahia Uncupita, Arequipa Region, Peru (16.8370 S, 72.291W), depth 9 m, coll. Y. Hooker & U. Zanabria (27/ XI /2008) .

Additional material. IZUA – POR 175 (voucher and slides deposited as MNRJ 9254 ), Punta Choros , La Serena, Chile (29.8166S, 71.28333 W), depth 13 m, coll. E. Hajdu & G. Lobo-Hajdu (21/V/2005) . MNRJ 9283 , Mejillones Peninsula , Antofagasta, Chile (23.083 S, 70.433 W), depth 13 m, coll. E. Hajdu & G. Lobo-Hajdu (24/V/2005) ; MNRJ 14875 , 14879 , Isla Damas , Punta Choros, Chile (29.2377S, 71.5197W), depth 10 m, coll. D. Schories (21/ XI/2009) .

Type locality. Punta Coles , Ilo, Moquega Region, Peru (17.7 S, 71.3808 W) .

Diagnosis. Hymedesmia (H.) reddish orange in situ, with visible circular porefields and oscules. Acanthostyles I partially spined (153–320 × 6–17 µm), acanthostyles II entirely spined (55–150 × 5–15 µm), (aniso)strongyles (128–275 × 2–8 µm), and arcuate chelae (16–25 µm), abundant at the surface.

Description ( Fig. 5A–B ). Thinly encrusting sponge (0.7–1.5 mm thick) ( Fig. 5A ). The largest individual (IZUA–POR 175) covered an area of 640 cm 2. Surface smooth, completely covered by small, circular porefields (≈ 2 mm in diameter). Some oscules scattered on the surface (0.7–3.0 mm diameter, Fig. 5B ). Consistency very soft and fragile. Color in life is reddish orange ( Fig. 5A–B ), turning to beige when preserved in ethanol.

Skeleton ( Fig. 5C ). Ectosomal skeleton with anisostrongyles forming bundles extending from surface to substrate. Porefield skeleton formed by many unitary strongyles in a mesh, organized as a conical structure. Subectosomal canals less than 0.8 mm in diameter. 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 substratum.Acanthostyles I support the ectosome without piercing it. Isochelae form a scattered layer at the surface, with some found in the choanosome. Incubated larvae present in MNRJ 9524 (≈ 300 µm diameter).

Spicules ( Figs 5D–J ; Table 1 ). [Only holotype measurements presented here; for additional data see Table 1 ]. Ectosomal anisostrongyles ( Figs 5F–H ), smooth and straight ( Fig. 5F ), with rounded and mucronate ends ( Fig. 5G–H ), 128– 167.9 –186 (± 13.4) × 2.7– 3.8 –5.4 (± 0.6) × 2.7– 3.7 –4.7µm (tyle). Choanosomal acanthostyles I ( Fig. 5D ), acerate tips tapering gradually, rounded base, shaft slightly curved, with spines occupying the basal two thirds of its length, spines mostly slightly curved, those of the base larger than those of the shaft, 153– 215.6 –283 (± 37.2) × 5– 11.3 –13 (± 1.4) µm. Choanosomal acanthostyles II ( Fig. 5E ), straight, tapering gradually, mucronate tip and rounded base, spines spread all over, 88– 107.1 –128 (± 8.7) × 5– 8.3 –10 (± 0.9) µm. Arcuate chelae ( Fig. 5I–J ), one free spatulate ala and two lateral alae semi-fused with the shaft, which is characteristically curved, bow shaped, 19– 21.8 –24 (± 1.3) × 2.8– 2.9 –3.1 (± 0.1) µm.

Ecology. The sponge was epibiont on dead cirripeds, bryozoans, and serpulid polychaetes at 9–13 m depth.

Distribution. Known from Arequipa and Moquega regions in Peru, and from central-northern Chile (Antofagasta and Punta Choros), spanning the latitudes 16.84º to 29.24º S.

Etymology. The specific epithet “ humboldti ”, used as a noun in apposition, refers to the Humboldt current flowing north along most of the Chilean and Peruvian coasts, including all the localities the species was recorded from.

Remarks. This species is quite similar to H. (H.) peruana sp. nov., but has somewhat larger ectosomal tornotes, only two categories of acanthostyles, and more pronouncedly curved chelae concentrated in the ectosome.

Figures

FIGURE 5. Hymedesmia (H.) humboldti sp. nov. A–B, live specimen (MNRJ 12078); C, skeleton architecture in transverse ground section; D, choanosomal acanthostyle I; E, choanosomal acanthostyle II; F, ectosomal tornote; G–H, details of F; I–J, isochelae. Scale bars: A, approx. 2 cm; B, approx. 0.5 cm; C, 200 µm D–F, 100 µm; G–H, 20 µm; I–J, 10 µm.