Advhena magnifica, Castello-Branco & Collins & Hajdu, 2020

Castello-Branco, Cristiana, Collins, Allen G. & Hajdu, Eduardo, 2020, A collection of hexactinellids (Porifera) from the deep South Atlantic and North Pacific: new genus, new species and new records, PeerJ 8, pp. e 9431-e 9431 : 13-21

Advhena magnifica sp. nov.

( Figs. 8–10 )

Type Material

Holotype. USNM 1424107 . Pigafetta Guyot, E of the Marianas’ Trench, Paci fi c Ocean (Deepwater Exploration of the Marianas, ‘Deep Discovery’ ROV; Cruise EX1605L1 ; 15 56 ′ 31.383 6 ″ N / 148 36 ′ 53.355 6 ″ E), coll. R/V ‘ Okeanos Explorer ’, 2,028 m depth, 04.V.2016. EZID: http://n 2t.net/ark:/65665/31f4b11ee-5685-4b5b-befb-58efb94b3c6c LSID: urn:lsid:zoobank.org:act:52622D46-619E-432B-9D80-77795C5FD8A7

Diagnosis

Advhena magnifica sp. nov. is the only representative of Bolosominae with microscleres as discasters (480–570 m m diam.), discohexasters (55–60 m m diam.), codonstaurasters (103–160 m m diam.), discohexasters with calycocomes (138–255 m m diam.) and graphiocomes (150 m m (N = 1); 20–33 m m primary rays’ diam.).

EXTERNAL MORPHOLOGY. Pedunculate sponge characterized by mushroom-like shape (136 mm in diameter and 75 mm thick) with lateral openings concentrated on one side of the body, each one with 50 and 18 mm in diameter, and peduncle longer than 154 mm in length (broken) and 16 mm in diameter (at least four times the body size).

SKELETON AND SPICULES. Peduncle with cemented diactins (1,310–2,825 × 20–60 m m) and a few short hexactins and pentactins with distal ray reduced (195–250 × 2–5 m m). Choanosomal diactins with rough ends and sometimes rudiments of actins in the middle region; 1,075–2,575 × 15–18 m m. Dermal and atrial hexactins smooth with rough ends and shorter distal ray; 300–789 × 10–18 m m, and distal ray 80–110 × 12–25 m m; rare pentactins as dermalia/atrialia (450–680 × 15–18 m m). Microscleres discasters (480–570 m m diameter); discohexasters (50–75 m m diameter); codonstaurasters (103–160 m m diameter) usually with four to six central axis and fi ve to seven secondary rays (sometimes bent over), discs with eleven teeth; calycocomes (138–255 m m diameter), and graphiocomes (150 m m (N = 1); 20–33 m m primary rays’ diameter) with six central rays and straight and short secondary rays (maximum found 65 m m length).

DISTRIBUTION AND ECOLOGY. Known from its type locality in the Pigafetta Guyot, east of the Mariana Trench (Paci fi c Ocean), 2028 m depth. Some video footage of likely Advhena specimens was obtained by NOAA ‘Okeanos’ expedition a year later (25 July 2017) at a locality rich in sponge diversity, dubbed the “Forest of the Weird”, as part of the Laulima O Ka Moana: Exploring Deep Monument Waters Around Johnston Atoll expedition (EX1706; on https://oceanexplorer.noaa.gov/ okeanos /explorations/ex1706/ dailyupdates/media/video/dive11-forest/forest.html).

ETYMOLOGY. The speci fi c epithet is used as a noun in apposition, and refers to the species’ magni fi cent, beautiful appearance.

Remarks

Considering all genera of Bolosominae (see table 2), Advhena gen. nov. appears most similar to Neocaledoniella Tabachnick & Lévi (2004) , the only other bolosomine with calycocomes and graphiocomes. However, the new species has discaster, discohexaster and codonstauraster microscleres. In addition, Neocaledoniella presents heavily spined pinular hexactins, missing here. Thus, we propose a new monospeci fi c genus within Bolosominae to include Advhena magnifica gen. et sp. nov.

Figures

Figure 8 Advhena magnifica gen. et sp. nov. holotype (USNM 1424107). (A‒D) specimen in situ; (E and F) details of specimen in ethanol (1 cm). Full-size DOI: 10.7717/peerj.9431/fig-8

Figure 9 Advhena magnifica sp. nov. (A) diactin; (B) detail of hexactin extremity; (C and D) pentactines; (E) discasters (discohexaster); (F and G) discohexaster; (H and I) codonhexasters (J) calydiscohexasters (partially broken); (K) graphiocome (primary rays with one of the secondary rays). Scales: (A) 250 mm; (B, H, I and J) 20 mm; (C–E) 100 mm; (F, G, J and K) 10 mm. Full-size DOI: 10.7717/peerj.9431/fig-9

Figure 10 Illustration of Advhena magnifica gen. et sp. nov. microscleres. (A) Codonstauraster; (B) graphiocome (Illustrations by Nicholas Bezio). Full-size DOI: 10.7717/peerj.9431/fig-10