Spongia (Heterofibria) nazcaensis, Fernandez & Zapata-Hernández & Sellanes & Hajdu, 2025

Fernandez, Julio C. C., Zapata-Hernández, Germán, Sellanes, Javier & Hajdu, Eduardo, 2025, Description of two new species of sponges (Demospongiae, Porifera) from the Nazca Desventuradas Marine Park and overview on diversity and biogeography of poriferans in oceanic islands of the SE Pacific, Zootaxa 5659 (3), pp. 301-334 : 318-326

Spongia (Heterofibria) nazcaensis sp. nov.

( Tables 3–4; Figures 4–5 )

Diagnosis. Spongia (Heterofibria) occurring in Pacific with a combination of massive to lobate habit and very thin fibers, thickest ones (primary fibers) reaching less than 60 µm.

Type locality. San Ambrosio Island , Desventuradas Islands Archipelago, SE Pacific .

Material examined. MNRJ 18627 (holotype), San Ambrosio Island , Desventuradas Islands Archipelago, SE Pacific (-26.33635; -79.88571), 20 m depth, coll. C. F. Gaymer, 13 February 2013 (Station M 11; see Friedlander et al. 2016) . MNRJ 19914 (paratype), same data as holotype .

Additional material examined. MNRJ 18614 , Hanga Roa, Rapa Nui, SE Pacific (-27.14500; -109.43500), 9.7 m depth, coll. G. Zapata-Hernández in September 2014 .

Description. Habit, massive to slightly lobate ( Fig. 4A–C ). Measurements 10 × 5.5 × 2.2 cm (holotype), 6 × 3.5 × 1.2 cm (paratype), 5.5 × 3.5 × 1.3 cm (additional material). Surface, slightly micro-conulose with a tightly adhered, thin, dark membrane ( Fig. 4D–F ). Oscules, numerous, small (up to 2 mm in diameter), often slightly raised and distributed on the darker surface (upper side). A few oscules on the lighter surface (underneath). Consistency, firm, but compressible and elastic. Texture, slightly rough. Color in life, not recorded, and in ethanol, light brown to dark-brown (upper side) and beige (underneath and internally) ( Fig. 4A–C ).

Skeleton and fibers. Irregular to polygonal reticulation of homogeneous primary, secondary and pseudo-tertiary fibers ( Fig. 5A–I ). Primary fibers (30– 45 (±2.5)–55 µm; Table 3), few and cored by foreign debris (in part), sand grains and distinct broken spicules. Primary fibers, arranged axially and nearly parallel or anastomosing in the choanosome, piercing the surface up to 500 µm high. Both secondary fibers (14– 20 (±1)–24 µm; Table 3) and pseudo-tertiary fibers (2.5– 6 (±0.5)–9 µm; Table 3), uncored, dominant in the skeleton and connected to each other, as well as primary fibers. Meshes of secondary fibers, irregularly polygonal (diam. 30–350 µm). Pseudo-tertiary fibers, as a network (mesh diam. 20–120 µm), within meshes formed by secondary fibers, either interconnecting adjacent secondary fibers (more frequently) or interconnecting primary and secondary fibers (less frequently). Choanocyte chambers, rounded, up to 15 µm in diameter.

Substrate, depth range and ecology. Volcanic rocks, 9.7–20 m depth. The collection site at San Ambrosio Island corresponds to the exposed coast (Station M11, see Friedlander et al. 2016). Collection site from RN was characterized by a hard bottom of volcanic rocks covered mainly by Porites lobata and Pocillopora spp. reefs. Associated organisms were not observed in the analyzed material.

Distribution. Southeast Pacific: San Ambrosio Island (Desventuradas Islands; type locality) and Rapa Nui.

Etymology. The name “ nazcaensis ” is used as a noun in apposition and refers to the Nazca plate and Nazca ridge, since the new species has been recorded from oceanic islands on the extremities of this plate and close to the Nazca ridge, Rapa Nui (western record) and the Desventuradas Islands Archipelago (eastern record).

Remarks. In accordance with the WPD ( de Voogd et al. 2024), only 11 species of Spongia (Heterofibria) are currently known worldwide. The present study describes a new one and represents the first record of this taxon in the eastern Pacific region ( Table 4). Unfortunately, submarine images of the new species were not taken, then, its color in life is still unknown. However, we think that its habit in life is similar to the preserved, since its skeleton of spongin fibers is well developed and help maintain the shape after collection. Therefore, in the field, the new species could be probably identified by the combination of its massive to slightly lobate shape, consistency (firm, but compressible and elastic) and texture (slightly rough). But, with possibilities of confusion with other dictyoceratid sponges.

Spongia (H.) nazcaensis sp. nov. is distinguished from its congeners by the combination of a massive to slightly lobate habit and very thin fibers, the thickest ones (primary fibers) reaching less than 60 µm in thickness. Choanocyte chambers are very small in the new species (ca. 15 µm in diameter), but they have not been described in part of the known species of Spongia (H.). Thus, a comprehensive comparison of this character among all species is not possible.

Spongia (H.) nazcaensis sp. nov. has thin fibers approaching more closely those in three species in particular ( Table 4). Two of them from New Zealand (Southwest Pacific), namely Spongia (H.) decooki van Soest & Hooper, 2020 (in van Soest et al. 2020) and Spongia (H.) mokohinau Cook & Bergquist, 2001 , have fibers reaching up to 78 µm in thickness. However, both species have larger choanocyte chambers (up to 39 µm and 34 µm in diameter, respectively) and a massive base with upright lobes and conical turrets ( Cook & Bergquist 2001). The third species is Spongia (H.) smaragdus Samaai, Pillay & Janson, 2020 from Sodwana Bay, South Africa (Southeast Indian), with the thinnest (up to 45 µm thick) of all primary fibers among known species of Spongia (Heterofibria) . Samaai et al. (2020) have mentioned a chocolate-brown color to the preserved type material of Spongia (H.) smaragdus . Although it is similar to the one in preserved material of Spongia (H.) nazcaensis sp. nov., a remarkable lighter internal color can be observed in the new species (see description above). Furthermore, the large geographical distance between the known occurrences of Spongia (H.) smaragdus and Spongia (H.) nazcaensis sp. nov. renders the conspecificity of both rather unlikely.

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Spongia (Heterofibria) ] rubber; pf. 29– 49 –78 µm diam.; sf. 17– 30 –42 µm diam.; ptf. 4– 10 –17 µm diam.; cc. 26–32–39 µm diam. modified from Cook & Bergquist (2001) S. (H.) gorgonocephalus ha. small, massive, compact; su. no visible fibrous network, with opaque W Pacific (Pinnacles, Poor Cook & Bergquist, 2001 pinacoderm and distinctive elongate, narrow conules, or turrets; os. on Knights Islands, and Off Piercy longer turrets (1–3 mm diam.); ec. very light, pale grey (conserved); ic. Island, in Bay of Islands, New light greyish-cream (conserved); co. firm and compressible; te. smooth Zealand)/ 90–152 m (based on the illustration); pf. 38– 55 –126 µm diam.; sf. 12– 29 –55 µm diam.; ptf. 4– 8 –9 µm diam.; cc. not described modified from Cook & Bergquist (2001)

S. (H.) manipulatus Cook & ha. massive, forming a compact hemispherical mound; su. coarsely and W Pacific (Sail Rok, Hen and

Bergquist, 2001 abundantly conulose, with upright conical turrets; os. on turrets (3–8 mm Chickens Islands and Tutukaka diam.), with an internal sphincter-like membrane; ec. very light, pale grey Harbour, in Hauraki Gulf, New

(conserved); ic. light greyish-cream (conserved); co. firm and moderately Zealand)/ 12–20 m

compressible; te. turrets are softer and flabby than the other regions; pf.

35– 78 –184 µm diam.; sf. 24– 34 –46 µm diam.; ptf. 4– 13 –23 µm diam.; cc. 21– 26 –34 µm diam. modified from Cook & Bergquist (2001)

S. (H.) mokohinau Cook & ha. solid base with distinct conical turrets; su. exposed fiber reticulum W Pacific (Moko Hinau and

Bergquist, 2001 (1–3 mm deep in reticulum) and finely conulose; os. on turrets (3–5 mm Tawhiti Rahi, in Poor Knights diam.) with a surrounding fringe of exposed skeletal fibers or covered Islands, New Zealand)/ depth by a fine mesh; ec. pale grey (conserved); ic. Khaki-straw brown not reported

(conserved); co. compressible; te. soft; pf. 29– 39 –78 µm diam.; sf. 13–

21 –29 µm diam.; ptf. 3– 8 –10 µm diam.; cc. 23– 29 –34 µm diam. modified from Cook & Bergquist (2001)

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Obervation: Spongia (H.) biformis Kelly, 2009 (in Kelly et al. 2009) has been considered nomen nudum by R.W.M. van Soest, for which reason it is not included in the comparison carried out here (see ‘notes’ in the record of S. (H.) biformis in de Voogd et al. 2024 ).

Spongia (H.) catarinensis Mothes & Lerner, 2006 (in Mothes et al. 2006) from SE Brazil shallow waters has external characters comparable to those observed in Spongia (H.) nazcaensis sp. nov. viz., massive habit, micro-conulose surface, oscules slightly raised, darker external color and lighter internal color. However, Spongia (H.) catarinensis has considerably thicker fibers than those in the new species (up to 100 µm thick vs. up to 55 µm thick, respectively). Furthermore, biogeographically, conspecificity of both is rather unlikely too.

Figures

FIGURE 4. Spongia (Heterofibria) nazcaensis sp. nov., A–F, habit of the types and an additional specimen: A, holotype (MNRJ 18627); B, paratype (MNRJ 19914); C, additional material (MNRJ 18614); D, detail of the holotype; E, detail of the paratype; F, detail of the additional material. Scale bars: A–C = 1 cm; D–F = 0.5 cm.

FIGURE 5. Spongia (Heterofibria) nazcaensis sp. nov., A–I, skeleton of the types and an additional specimen: A, transverse section of the holotype (MNRJ 18627); B, choanosomal reticulation of the holotype (pf = primary fibers, sf = secondary fiber, ptf = pseudo-tertiary fiber); C, detail of ectosomal region of the holotype; D, transverse section of the paratype (MNRJ 19914); E, choanosomal reticulation of the paratype (pf = primary fibers, sf = secondary fiber, ptf = pseudo-tertiary fiber); F, detail of ectosomal region of the paratype; G, transverse section of an additional material (MNRJ 18614); H, choanosomal reticulation of the additional material (pf = primary fibers, sf = secondary fiber, ptf = pseudo-tertiary fiber); I, ectosomal region of the additional material, with fibers and numerous spherical choanocyte chambers. Scale bars: A = 500 µm; B–C = 50 µm; D = 500 µm; E–F = 50 µm; G = 500 µm H = 50 µm; I = 10 µm.