Halicnemia

Halicnemia sp.

Figures 34 a–c

Material examined. RMNH Por. ex 9973 (slide only), Suriname, ‘ Snellius O.C.P.S. ’ Guyana Shelf Expedition, station B23A, 7.297°N 55.3883°W, depth 99–101 m, Van Veen grab, 27 April 1966.

Description. Encrusting, hispid. The tiny specimen was so small that no material was left after light microscopic and SEM slides had been made. No further material of this species was found after a careful search.

Skeleton. No details can be provided, but presumably the megascleres were arranged perpendicularly on the substratum, with acanthoxeas scattered in the near-substratum part of the sponge.

Spicules. (Figs 34 a–c) Tylostyles, tornotes, acanthoxeas.

Tylostyles (Figs 34 a,a1) long straight, except near the tyles where a slight gradual bend may be present, with prominent globular heads, 1344– 1843 – 2286 x 15 – 19.3 –28 µm.

Tornotes (Figs 34 b,b1) with a peculiar twisted bend in the middle, occasionally with an additional central tyle, 663– 1009 –1236 x 8.5– 12.5 –15 µm.

Acanthoxeas (Figs 34 c), curved gradually or more often with angular bend in the middle, provided with strong conical spines, 78– 91 – 97 x 5.5– 7.4 –10 µm.

Distribution and ecology. Guyana Shelf, sandy bottom, at around 100 m depth.

Remarks. This is the first record of the genus Halicnemia in the Western Atlantic. The genus has a chequered distribution in the Northwest Atlantic, Western Indian Ocean and South East Pacific (Van Soest et al. 2016). The present species stands out among the known species of Halicnemia by the twisted bends in the tornotes. It is doubtless an undescribed species, but I refrain from naming it in the absence of a proper specimen.