Parahigginsia strongylifera Van Soest, Meesters & Becking 2014

Parahigginsia cf. strongylifera Van Soest, Meesters & Becking, 2014

Figures 37 a–d

Parahigginsia strongylifera Van Soest et al. 2014: 423, figs 14–15.

Material examined. RMNH Por. 9882b, Suriname, ‘Luymes’ Guyana Shelf Expedition, station 1, 7.1667°N 53.5833°W, depth 104–130 m, bottom sandy calcarenite, 24 August 1970.

Description. (Fig. 37 a) Pale orange crust (in alcohol) on a specimen of Characella poecillastroides (cf. below). Surface wavy to microlobate, but otherwise smooth, no apparent oscules (presumably contracted). Overall size 7 x 4 cm, thickness about 2 mm. Consistency soft.

Skeleton. (Fig. 37 b) An isotropic but confused unispicular to paucispicular reticulation of oxeas. At the surface there is a thin crust of acanthomicroxeas.

Spicules. (Figs 37 c–d) Oxeas, acanthomicroxeas.

Oxeas (Fig. 37 c), lightly curved, robust, cigar-shaped, with mucronate apices, occasionally with one of the ends rounded, style-like, 171– 196 –204 x 9 – 11.1 –14 µm.

Acanthomicroxeas (Figs 37 d,d1), thin, curved or straight, with thin, long, sharp spines, evenly distributed, 74– 83.3 –102 x 0.5– 1.1 –2 µm.

Distribution and ecology. Guyana Shelf, Bonaire (if conspecific), encrusting hard substrates including sponges, at 104–238 m depth.

Remarks. The identification is made with hesitation. There are differences with the type material from Bonaire (RMNH Por. 9251): the strongyles which are the basis of the species name are replaced by oxeas in the present specimen, which are also shorter than the strongyles of the type. The type material consists of small pale blueish patches on deep-water rocks, whereas the present specimen forms a larger sheet encrusting a rough deepwater sponge. However, the preserved fragments of the type material (Van Soest et al. 2014: fig. 14c) and the encrustations reported here are remarkably similar in shape and color. Thinner growth stages of the type are oxealike (Van Soest et al. 2014: fig. 14d), so it is likely that the strongyles may be considered modified oxeas, the more so as the only other species of Parahigginsia (P. phakelloides Dendy, 1924) also has oxeas. The acanthomicroxeas of both are similar in size and shape, sharing the characteristic thin sharp spines.