Cinachyrella anatriaenilla Fernandez, Kelly & Bell, 2017, sp. nov.

Cinachyrella anatriaenilla sp. nov.

(Fig. 2–4; Table 1)

Acanthotetilla cf seychellensis, Redmond et al. 2013: 403 –404, Sup. Table 1, Fig. 10; Carella et al. 2016: 26 /33, Table 1, Figs. 3, 10.

Material examined. Holotype— CASIZ 194902, west side of Nu’utele Island, to the west of Ofu Island, Manu’a Group of Islands, American Samoa, 14.174 S, 169.686 W, 6 m depth, 12 Oct 2001, coll. P. L. Colin (CRRF), fragments of holotype deposited as CASIZ 194902 and MNRJ 17612; Paratypes— CASIZ 194903, ibid, fragments of paratype deposited as MNRJ 17613; USNM 1422126, ibid, fragments of paratype deposited as CASIZ 301478, and MNRJ 17614, sequences 18S deposited in GenBank accession number KC902033, PorTol short Id. NCI318, and Sponge Barcoding database submission number SBD #1648.

Comparative type material. MNHN DJV97: C. levantinensis Vacelet et al. 2007, paratype 3; RMNH POR. 2877: A. celebensis De Voogd & van Soest 2007; ZMA POR 3814: A. gorgonosclera van Soest 1977; MNRJ 6359: A. rocasensis Peixinho et al. 2007; RMCA 1410: A. seychellensis; UFBA 1902: A. walteri Peixinho et al. 2007. Other comparative material. UFBA POR 2064, UFBA POR 2369: C. kuekenthali, identified by J.C.C.F.

Type location. Nu’utele Island, American Samoa.

Distribution. Known only from the type locality.

Description. Sponge spherical to hemispherical, elongate oval to irregularly shaped overall (Fig. 2 A–F), or conjoined (e.g. Fig. 2 E); holotype (Fig. 2 C–D) 30 mm diameter× 20 mm high, paratype (Fig. 2 E) 21 mm diameter 13 mm high, and paratype USNM 1422126 (Fig. 2 F) 22 mm diameter × 10 mm high. Several reproductive ‘buds’ or extensions were observed in shallow cavities on the surface of the holotype (Fig. 2 G). Surface smooth, slightly undulating macroscopically, hispid in sections (spicules 1.5 mm high), small amounts of sand on surface. Oscules few, membranous, apical and small, up to 4 mm diameter 3 mm deep in preserved state (Fig. 2 H). Porocalices shallow, hemispherical, small, up to 2 mm diameter in preserved state, surrounded by several large oxeas up to 2 mm high, and with convergent channels (Fig. 2 I). Texture slightly compressible, tears relatively easily. Colour in life yellow, light beige in preservative.

Skeleton. Ectosomal region frequently sharply differentiated from the underlying choanosome to about 1 mm deep (Fig. 3 B); ectosome translucent pale yellow and cellular in appearance with no demarcating fibrillar collagen evident. Reproductive buds are evident on the surface (Fig. 3 A–B). Porocalices have a single aquiferous channel are evident in Fig. 3 D. Choanosomal region fully radial (Fig. 3 A), with loose bundles of oxeas emanating from a distinct center towards the surface, in between which lie scattered oxeas, protriaenes and anatriaenes; oxeas and triaenes project about 2000 µm beyond the surface. Choanosome dense and traversed by a few circular channels up to 500 µm diameter. Microacanthoxeas and sigmaspires scattered throughout the choanosomal and ectosomal regions. Embryos pigmented and visible within the choanosome and ectosome (Fig. 3 A, E).

Spicules (measurements based in all material examined). Megascleres (Table 1; Fig. 4). Oxea I (Fig. 4 A–B) straight to slightly curved, smooth, extremities stepped, often with blunt tips: 2589.5 (1800–4000) (±553) µm× 21 (16–28) (±3.4) µm, n=90. Oxeas II (Fig. 4 C) smaller and finer than the previous category, extremities sharp, often with hastate tips: 1170 (625–1350) (169)µm× 9. 2 (5–12) (±1.6) µm, n=90. Protriaenes (Fig. 4 D) relatively small and slender, with hair-like rhabdome: 1275.1 (625–2875) (±471) µm 3.9 (2.5–6) (1.1) µm, n=30. Protriaene cladome with three equal clads, slightly curved (most common) or slightly angulate (less common), malformed cladomes with bent clads or monaenes (Fig. 4 E); clads at an angle of 120 to the rhabdome: clads: 47.7 (25–70) (±11) µm 3 (2–5) (±0.9) µm, n =30. Anatriaenes (Fig. 4 F) slightly smaller and thinner than the protriaenes, with hair-like rhabdome: 984.2 (700–1300) (±163) µm× 3.2 (2.5–4) (±0.4) µm, n =30. Anatriaene cladome with short equal clads at an angle of 45–60 to the rhabdome, malformed cladomes with more than three clads or monaenes (Fig. 4 G): 29.2 (18–38) (±6) µm× 2.7 (2–4) (±0.5) µm, n =30.

Microscleres (Table 1; Fig. 4). Microacanthoxeas (Figs. 4 H–I) straight to slightly curved, very thin, with small spines (up to 0.2 µm in length) densely distributed over the shaft, extremities usually smooth: 141.5 (112–208) (±19) µm× 2.2 (1.5–2.5) (±0.3) µm, n=90. Sigmaspires (Fig. 4 J) contorted c - or s -shaped, with small spines (up to 0.5 µm high) densely distributed over the entirely shaft: 15 (10–22) (±2) µm×up to 1 µm, n=90.

Reproduction. Spherical to oval-shaped reproductive ‘buds’ or extensions up to 1 mm diameter can be found in shallow surface cavities (Fig. 2 G) and nested between large megascleres that project from the surface of all specimens (Fig. 3 A, B). These ‘buds’ contain mature microacanthoxeas and are connected to the parent sponge by an extension of the ectosome (Fig. 3 C). Pigmented oocytes are visible within the choanosome (Fig. 3 A, E).

species oxeas an. anatriaenes, pr. protriaenes, pl. sp. spherules, si. plagiotriaenes, or. ortotriaenes sigmaspires, mi. microacanthoxeas

C. australiensis (Carter 5715‾6350×38‾42.3 an. “not observed but maybe occur si. 17 1886) as Tethya cranium, pr. rhabd.” “length a little less than that of the mi. 211.5×* var. australiensis from the spicules of the body; i.e. oxeas”, clad. 135.5×* South Australia

Substrate, depth range and ecology. Sponges were attached to the walls of shallow sea caverns, on cliffs, on the west side of Nu’utele Island, at a depth of 6 m. These caverns experience strong wave and surge action. All specimens have loose, small, cigar-shaped oxeas typical of haplosclerid sponges, on their surface.

Etymology. Named for the possession of highly characteristic small anatriaenes (anatriaene + illa — female adjectival suffix in Latin related to diminutive of a name).

Remarks. When the specimens of C. anatriaenilla sp. nov. were first collected in 2001, they were tentatively identified as Acanthotetilla seychellensis due to the possession of relatively small acanthose oxeas. Re-examination of the holotype of A. seychellensis here (Fig. 5 A–F) confirms that they are quite separate: A. seychellensis has an encrusting habit (Fig. 5 B–D) and a probable ectosomal palisade of megacanthoxeas (see also Fernandez et al. 2012). In terms of geographic proximity, the nearest species of Acanthotetilla to C. anatriaenilla sp. nov., is A. celebensis from Indonesia, but this has a semiglobular habit, a cortical skeleton of megacanthoxeas in two categories (300 – 575 µm×20–43 µm and 199–310 µm×10–18 µm), one size category of oxeas, plus anatriaenes, protrienes and sigmaspires (species has been reviewed by Fernandez et al. 2012). The general characteristics of C. anatriaenilla sp. nov. do not agree with any of the type material of species of Acanthotetilla examined by us here.

Cinachyrella anatriaenilla sp. nov. was later compared to C. australiensis which also had microacanthoxeas (Table 1) with a broad geographic distribution across the West Central Pacific, Southeast Asia and the Western Indian Ocean. However, C. australiensis differs from the new species on the basis of having only one category of oxeas (5715–6350 µm×38–42 µm) verses two categories in C. anatriaenilla sp. nov., the former having oxeas that are almost 2000 µm larger than those of C. anatriaenilla sp. nov. (max. dimension 4000 µm×28 µm). Protriaenes in C. australiensis also have clads nearly twice the length (up to 135.5 µm long) of those in C. anatriaenilla sp. nov. (up to 70 µm long). Furthermore, a thin fibro-reticulate dermis was reported for C. australiensis by Carter (1886: 127) but was not observed in C. anatriaenilla sp. nov.; in the new species the ectosome is translucent pale yellow and cellular in appearance with no demarcating fibrillar collagen evident (Fig. 3 B).

Cinachyrella kuekenthali from the tropical western Atlantic has similar spiculation to that of C. anatriaenilla sp. nov. including two categories of large oxeas (Table 1). However, C. kuekenthali differs from the new species on the basis of having larger oxeas, over 1000 µm larger and nearly 20 µm thicker than those of C. anatriaenilla sp. nov. (max. dimension 4000 µm×28 µm). Furthermore, protriaenes in C. kuekenthali is also larger, have both rhabdome and cladis nearly twice the length and thrice the thickness (rhabd. 4600×18 and clad. 130 x 15) than those of C. anatriaenilla sp. nov. (rhabd. 2875×6 and clad. 70×5).

Cinachyrella anatriaenilla sp. nov. is also distinct from C. cavernosa in the possession of thinner large oxeas (up to 28 µm in C. anatriaenilla sp. nov. verses up to 80 µm in C. cavernosa) and is distinct from C. globulosa from the Galápagos Islands in it’s lack of plagiotriaenes and orthotriaenes (Table 1).