Antho (Acarnia) pellita, Van Soest & Meesters & Becking, 2014

Van Soest, Rob W. M., Meesters, Erik H. W. G. & Becking, Leontine E., 2014, Deep-water sponges (Porifera) from Bonaire and Klein Curaçao, Southern Caribbean, Zootaxa 3878 (5), pp. 401-443 : 421-422

Antho (Acarnia) pellita new species

Figures 13a–i

Material examined. Holotype: RMNH Por. 9240, Caribbean Netherlands, Bonaire, Kralendijk Pier (Dive 2), 12.1469°N 68.2821°W, on a large sponge at 108 m, coll. L.E. Becking & E. Meesters, field nr. BON1/ BDR009 , 30 May 2013.

Description. Red, optically smooth, but microhispid encrustation ( Fig. 13a ) on Neopetrosia eurystomata n. sp. (see below). Lateral expansion of the encrustation is 11 x 6 cm, the fragment preserved measures 3 x 2 x 0.2 cm. Consistency soft.

Skeleton. Choanosomal skeleton ( Fig. 13b ) a renieroid reticulation of acanthostrongyles, echinating at the nodes by longer acanthostyles. Subectosomal skeleton single long smooth styles, heads embedded in the choanosomal reticulation. Ectosomal skeleton bouquets of subtylostyles or single strewn subtylostyles.

Spicules. Principal styles, subtylostyles, acanthostyles, acanthostrongyles, toxas, palmate isochelae.

Styles ( Fig. 13c, 13c 1 ), usually smooth, but occasionally with a few spines on the head, curved, 300– 394 –498 x 6– 13 – 16 µm.

Subtylostyles ( Figs. 13d, 13d 1 , 13e , 13e 1 ), with microspined heads, in a large size range, possibly divisible in two groups (165–298 and 310–470 µm), overall range 165– 306 –470 x 1.5– 2.5 – 4 µm.

Acanthostrongyles ( Fig. 13f ), heavily spined at both rounded ends, less densely spined on the shaft, 90– 101 –110 x 7.5– 9 –10.

Acanthostyles ( Figs. 13g, 13g 1 ), longer than the acanthostrongyles, spined densely and uniformly along the shaft, more densely spined on the head, 130– 151 –180 x 7.5– 9 –10.

Toxas ( Figs. 13h, 13h 1 ), with a shallow curve, ends microspined or rugose, in a large size range, 66– 142 – 272 µm.

Palmate isochelae ( Fig. 13i ), normal shaped, symmetrical, 13– 14 – 15.5 µm.

Ecology and distribution. Known only from the type locality at the lower edge of the mesophotic zone.

Etymology. pellita (L.) means ‘forming a skin’, referring to the encrustation on another sponge.

Remarks. The new species belongs to the subgenus Acarnia because of its combination of acanthostrongyles making up the basal reticulation and acanthostyles, echinating the nodes of this reticulation. The species is closest to Antho (Acarnia) penneyi ( De Laubenfels, 1936 as Holoplocamia ) from 70 m depth off Florida, likewise encrusting and basically with the same spicule complement. Differences are the smaller acanthostyles (only up to 97 µm) and toxas (only up to 80 µm), and the shape of the chelae which are contort unlike those of our new species. Other Central West Atlantic Antho species are encrusting Antho (Antho) barbadensis Van Soest & Stentoft, 1988 from Barbados, differing a.o. in the absence of acanthostrongyles, encrusting Antho (Acarnia) delaubenfelsi ( Little, 1963 as Holoplocamia ) from the Gulf of Mexico, differing a.o. by its lack of acanthostyles, and lamellate Antho (Plocamia) gymnazusa ( Schmidt, 1870) from Florida, which differs by its habit and its possession of dumbbellshaped spicules.

Figures

FIGURE 1. Map showing the positions of Bonaire and Klein Curaçao (Southern Caribbean), where the present collections were obtained. Insets show details of locations and course of dives 2–4 of the Curasub.

FIGURE 13. Antho (Acarnia) pellita n. sp., holotype RMNH Por. 9240, a. habit encrusting on the base of the holotype of Neopetrosia eurystomata n. sp., b. cross section of the skeleton, c–i. SEM images of the spicules, c. style, c1. details of style, d. long subtylostyle, d1. details of long subtylostyle, e. short subtylostyle, e1. details of short subtylostyle, f. acanthostrongyle, g. acanthostyle, g1. thin growth stage of acanthostyle, h. toxas, h1. microspined apex of toxa, i. palmate isochela.