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

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225 : 56-58

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.

Figures

FIGURE 37. Parahigginsia cf. strongylifera Van Soest, Meesters & Becking, 2014, a, habitus encrusting Characella poecillastroides, RMNH Por. 9882 (scale bar = 1 cm), b, light microscopic image of the peripheral skeleton, c – d, SEM images of spicules, c, oxea, d, acanthomicroxea, d 1, detail of d.