Crella (Pytheas) desventuradae Fernandez, Gastaldi, Zapata-Hernández & Hajdu, 2021

Fernandez, Julio C. C., Gastaldi, Marianela, Zapata-Hernández, Germán, Pardo, Luis M., Thompson, Fabiano L. & Hajdu, Eduardo, 2021, New species of Crella (Pytheas) Topsent, 1890 and Crellomima Rezvoi, 1925 (Crellidae, Poecilosclerida, Demospongiae) from Chilean shallow and Argentinean deep waters, with a synthesis on the known phylogenetic relationships of crellid sponges, Zootaxa 5052 (3), pp. 353-379 : 359-366

Crella (Pytheas) desventuradae Fernandez, Gastaldi, Zapata-Hernández & Hajdu , sp. nov.

( Table 2 ; Figures 4–5 )

Type locality. San Ambrosio Island , SE Pacific .

Material examined. Holotype — MNHNCL POR-15019 , San Ambrosio Island , Desventuradas Archipelago, SE Pacific (- 26.33892500 S, - 79.90749722 W), 10–20 m depth, coll. C.F. Gaymer, 15 th February 2013. Fragment of holotype under MNRJ 19228 and IZUA-POR 171 .

Diagnosis. Only Crella (Pytheas) in the Pacific being massive, yellow in life, with tornotes (130–168/2.4–2.6 µm), three categories of acanthostyles (choanosomal, I 90–104/2.5–3.5 µm and II 60–66/2.5–3.5 µm; ectosomal 40–52/2.5–2.8 µm) and arcuate isochelae (11.5–14.5 µm).

Description. Massive to slightly lobate ( Fig. 4A ); holotype in life, 30 (L) x 30 (W) x 4 cm (H) and fragment preserved, 6 (L) x 6 (W) x 4 cm (H). Surface irregular and slightly corrugated, with several subectosomal channels and a thin, strongly adhered membrane ( Figs. 4A–C ). Oscules small, scattered or grouped ( Figs. 4A–B ) and partially covered by a thin membrane ( Fig. 4D ). Pores very small and grouped as pore sieves, with ca. 1 mm in diameter, in preservative ( Figs. 4E–F ). Consistency firm, but compressible. Texture slightly rough. Color yellow in life and beige in preserved specimen.

Skeleton. Plumoreticulate architecture ( Fig. 5A ). Ectosomal region with several tornotes in vertical arrangement and in bouquets, usually protruding up to 50 µm above the surface ( Fig. 5B ). Beneath the surface (subectosomal region) tornotes in paratangential arrangement ( Fig. 5B ) and in slender tracts (ca. 20–50 µm thick), these latter coring spongin fibers ( Fig. 5C ), ca. 50–100 µm thick, throughout the ectosome and choanosome. Acanthostyles (ectosomal category) in tangential to paratangential arrangement at the ectosome and subectosome ( Fig. 5D ). Choanosomal region with a well-developed reticulation of spongin fibers, 50–150 µm thick, making rounded to polygonal meshes, ca. 300–650 µm wide ( Fig. 5E ), echinated by two categories of choanosomal acanthostyles ( Fig. 5F ). Spongin fibers are frequent throughout all skeletal regions; fibers have parts not fully echinated. Some ectosomal and choanosomal acanthostyles occurring into the fibers too ( Fig. 5C, 5F ). All categories of acanthostyles (ectosomal and choanosomal) are distinguished by size (length and width) and patterns of spination. Tornotes, ectosomal and choanossomal acanthostyles and arcuate isochelae occur scattered throughout the choanosomal region. Further, a few arcuate isochelae occur at the ectosomal region and more frequently around choanosomal channels. In spongin there are wide rounded subectosomal (up to 1000 µm longer length) and choanosomal channels (up to 3000 µm longer length).

Spicules. Megascleres ( Table 2 ). Tornotes ( Figs. 5G, 5H ) straight and smooth, tips usually mucronate; juvenile forms slender: 130– 150.8 (14.4)–168/2.4– 2.5 (0.1)–2.6 µm. Choanosomal acanthostyles I ( Figs. 5G, 5I ), largest category of acanthostyles, straight, not fully spined, blunt bases (no tyle), tips acerate or slightly blunt; spines small (up to 2.5 µm high), straight to slightly bent towards the bases, usually absent on the apical third; juvenile forms slender, with smaller and straighter spines: 90– 98.2 (5.7)–104/2.5– 3.1 (0.4)–3.5 µm. Choanosomal acanthostyles II ( Figs. 5F, 5J ), intermediate category of acanthostyles, as thick as previous, but almost fully spined, spines usually absent from apical fourth, small (up to 3 µm high), straight or slightly bent towards base; juvenile forms slender, with smaller, straight spines: 60– 64.2 (2.7)–66/2.5– 3.2 (0.4)–3.5 µm. Ectosomal acanthostyles ( Figs. 5G, 5K ), the smallest category of acanthostyles, slightly curved to sinuous, isodiametric, fully spined, blunt bases (no tyle), tips conical to acerate; spines small (up to 2.5 µm high), straight, uniformly distributed; juvenile forms, slender with several smaller and thinner spines: 40– 46.6 (4.4)–52/2.5– 2.7 (0.2)–2.8 µm. Acanthoxeas ( Fig. 5L ), rare, pattern of spination (fully spined) closer to the ectosomal acanthostyles: average of 50/2.5 µm (n = 2). Microscleres ( Table 2 ). Arcuate isochelae ( Figs. 5G, 5M ) in one size category, axis curved, alae slightly rounded and relatively short; distance between opposite alae, 1/3 (or a bit over) of maximum chelae length; juvenile forms with slender axis and smaller alae (reduced alae): 11.5– 13.6 (1.2)–14.5 µm.

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Ecology. Specimen grew over hard bottom covered by calcareous algae.

Distribution. Provisionally endemic to San Ambrosio island (type locality) in Desventuradas Archipelago (- 26.33333333 S, - 79.88333333 W), ca. 900 km from the Chilean coast ( Fig. 1 ), belonging in the Nazca-Desventuradas Marine Park.

Etymology. The name ‘desventuradae’ is a reference to the Desventuradas Archipelago, where the type locality of the new species is located.

Remarks. The new species constitutes only the second species of sponge reported from San Ambrosio Island, located in the National Nazca-Desventuradas Marine Park. Only Pseudosuberites hyalinuus ( Ridley & Dendy, 1887) was known from there (see van Soest 2002b: 238; Fig. 9D , for a revision of this species as Pseudosuberites hyalina ).

Crella (P.) desventuradae Fernandez, Gastaldi, Zapata-Hernández & Hajdu , sp. nov. is set apart from all known species of Crella (P.) by the smaller dimensions of its spicule set; viz., tornotes up to 168/2.6 µm, acanthostyles (the larger ones) up to 104/3.5 µm, and arcuate isochelae up to 14.5 µm ( Table 2 ). A few acanthoxeas occur in C. (P.) desventuradae Fernandez, Gastaldi, Zapata-Hernández & Hajdu , sp. nov. as they do in C. (P.) chiloensis Fernandez, Gastaldi, Pardo & Hajdu , sp. nov. We believe these acanthoxeas to be deformed ectosomal acanthostyles due similar size, pattern of spination and position in the skeleton.

Although distant about 1365 km from each other, the two SE Pacific species are geographically closer to each other than to any of the other known Crella (P.) species ( Table 2 ). In addition, spiculation and dimensions of spicules in both are more similar than to those of any other known species of Crella (P.); viz., three categories of acanthostyles and one category each of tornotes and arcuate chelae, with measurements in the table 2. However, both species differ in the yellow vs. reddish orange color in life (Desventuradas vs. Chiloé spp.), relative quantity of spongin fibers in the skeleton (more fibers vs. less fibers, respectively), spination pattern of acanthostyles I (evenly distributed vs. more concentrated at the base, respectively) and dimensions of the acanthostyles (larger vs. smaller, respectively).Among these characters, C. (P.) desventuradae Fernandez, Gastaldi, Zapata-Hernández & Hajdu , sp. nov. can be mainly distinguished of C. (P.) chiloensis Fernandez, Gastaldi, Pardo & Hajdu , sp. nov. by a denser reticulation (making a mesh) of spongin fiber throughout all skeleton and less echinated fibers, while in the latter species, reticulation of spongin fibers (without a mesh) are heavely echinated and more frequent in the choanosome.

Figures

FIGURE 1. Map of collection points. A, southern South America and arrow pointing to 1—off Santa Cruz province, Argentina Sea. B, Desventuradas Archipelago and arrow pointing to 2—San Ambrosio Island. C, Chiloé Island and Corcovado Gulf showing zoomed out to D (arrows ponting to 3—Puñihuil, Cocotue bay, 4—Duahatao and 5—Metalqui Island) and zoomed in to E (arrow pointing to 6—Rada Negra, Palvitad fjord). Scale bars: A = 500 km; B = 10 km; C = 20 km; D–E = 5km. Map from Google Earth.

FIGURE 4. Crella (Pytheas) desventuradae Fernandez, Gastaldi, Zapata-Hernández & Hajdu, sp. nov.: type material in life and preserved (A–F). A, massive specimen in life (holotype—MNHNCL POR-15019). B, detail of the surface of the specimen in life with oscules and subectosomal channels. C–F, holotype in preservative (ethanol 70%) showing a cavernous choanosome (fragment of the holotype—MNRJ 19228) and a membrane at the surface (C, indicated by arrow), an oscule partially covered by the membrane (D), pore sieves (E) and a pore sieve in detail (F). Scale bars: A = 5 cm; B–C = 1 cm; D = 2 mm; E = 1 mm; F = 0.5 mm.

FIGURE 5. Crella (Pytheas) desventuradae Fernandez, Gastaldi, Zapata-Hernández & Hajdu, sp. nov.: skeleton (A–F) and spicules (G–M, in SEM and light microscopy) of the holotype―MNHNCL POR-15019. A, transverse section. B, ectosomal region. C, detail of a spongin fiber at the subectosomal region with ectosomal acanthostyles (iii) and tract of tornotes (t) inside it. D, Ectosomal and subectosomal regions with ectosomal acanthostyles. E, choanosomal region with mesh of spongin fibers echinated by choanosomal acanthostyles I and II. F, detail of a spongin fiber echinated by choanosomal acanthostyles I (i) and II (ii) and with ectosomal acanthostyles (iii) inside it. G, spiculation showing choanosomal acanthostyles I (i) and II (ii), ecotosomal acanthostyles (iii), tornotes (t) and arcuate isochelae (a). H, extremities of a tornotes; I, choanosomal acanthostyles I; J, choanosomal acanthostyles II. K, ectosomal acanthostyles. L, acanthoxeas (in light microscopy). M, arcuate isochelae. Scale bars: A = 500 µm; B–D= 50 µm; E =200 µm; F = 50 µm; G = 50 µm; H = 1 µm; I–K = 10 µm; L = 20 µm; M = 2 µm.

FIGURE 9. Crellomima sigmatifera Fernandez, Gastaldi & Hajdu, sp. nov.: skeleton (A–F) and spicules (G–N, in SEM) of the holotype―IZUA-POR 172. A, transverse section. B, tornotes in vertical arrangement at the subectosomal region. C, tornotes in bouquets at the ectosomal region. C, ectosomal layer of ectosomal acanthostyles.D, detail of the ectosomal layer with ectosomal acanthostyles. E, choanosomal reticulation of choanosomal acanthostyles I equinated by choanosomal acanthostyles II. F, choanosomal acanthostyles I and II echinating a basal plate of spongin, which covers debris. G, tornotes. H, extremities of the tornotes. I, choanosomal acanthostyles I. J, choanosomal acanthostyle II. K, ectosomal acanthostyles. L, anchorate isochelae I. M, anchorate isochelae II. N, sigmas. Scale bars: A = 500 µm; B–D = 50 µm; E = 250 µm; F = 100 µm; G = 50 µm; H = 5 µm; I–J = 50 µm; K–L = 25 µm; M = 5 µm; N = 25 µm.