Hymerhabdia kobluki, Van, Rob W. M., 2017

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225 : 118-119

Hymerhabdia kobluki sp. nov.

Figures 72 a–e

Hymerhabdia sp. Kobluk & Van Soest 1989: 1215.

Material examined. Holotype RMNH Por. 9844, Guyana, ‘ Snellius O.C.P.S. ’ Guyana Shelf Expedition, station H57, 7.595°N 56.8767°W, depth 94 m, bottom coarse sand shells, 11 May 1966 .

Additional material. ZMA Por. 12584, Caribbean Netherlands, Bonaire, W coast N and S of Kralendijk , 12.15°N 68.278°W, framework cavities, depth 24–30 m, coll. D.R. Kobluk #BO-84-12, 1988 ; ZMA Por. 22017, Colombia, Cartagena, Islas del Rosario, Isla Pavitos , SCUBA, 25 m depth, coll. M. Kielman #82, 11 October 1990.

Description. ( Fig. 72 a) Microlobate sponge encrusting a piece of limestone. The small lobes are separated by thin grooves. Surface microhispid, no oscules are visible (preserved state, likely contracted). Lateral expansion about 3 x 2 cm, thickness 2–3 mm. Color (in alcohol) dull yellow to beige (probably orange in life, because the additional Colombian specimen ZMA Por. 22017 was reported to be orange in life). Consistency firm.

Skeleton. ( Fig. 72 b) The small lobes are V-shaped, dense masses of erect styles, heads buried in a lateral, confused, mass of oxeas. No special ectosomal skeleton.

Spicules. ( Figs 72 c–e) Styles, oxeas.

Styles ( Figs 72 c–d), straight or slightly curved, predominantly just below the head, in a large range of length and thickness, incompletely sorted into (1) larger thick styles ( Figs 72 c,c1) 632–1176 x 12–36 µm, (2) short thick styles 498–570 x 24–31 µm, and (3) short thin styles ( Fig. 72 d1) 264–387 x 9–18 µm, presumed to be thin growth stages. Overall size of styles 264– 736 – 1176 x 9 – 24.1 –36 µm.

Oxeas ( Figs 72 e,e1), mostly provided with a sharp bend in the middle or slightly excentrally, usually sharply pointed at both ends, but strongylote forms are present, 264– 424 –601 x 9 – 14.9 –19 µm.

Distribution and ecology. Guyana Shelf, Bonaire, Colombian Caribbean, in reef caves at 24–30 m depth ( Kobluk & Van Soest 1989) and on sandy bottom at 94 m depth ( Guyana Shelf).

Etymology. Named after the late Professor D.R. Kobluk of the University of Toronto Mississauga, who collected the first specimen of the species from Bonaire.

Remarks. This species was previously reported by Kobluk & Van Soest (1989) from Bonaire . Apart from this find, Hymerhabdia species have so far not been reported from the Central West Atlantic. The genus is known mostly from the Mediterranean-Atlantic region , with a single species, H. oxeata ( Dendy, 1924) (p. 349, originally as Bubaris oxeata ) recorded from Northern New Zealand . This species shows considerable similarity with the present new species, virtually the only difference being the smaller size of the oxeas, given as 270 x 12 µm by Dendy, remeasured later by Alvarez & Van Soest (2002) as 180–310 x 5–10 µm. The structure and the great size range of the styles is almost exactly that of the Guyana species . The New Zealand species was made the type of the genus Uplexoa De Laubenfels, 1936 , subsequently synonymized with Hymerhabdia by Alvarez & Van Soest (2002) (p. 752). Because now two species with closely similar properties are found to exist it might be in order to revive the genus Uplexoa .

Figures

FIGURE 72. Hymerhabdia kobluki sp. nov., a, habitus of holotype RMNH Por. 9844 (scale bar = 1 cm), b, cross section of skeleton, c – e, SEM images of spicules, c, large thick styles, c 1, details of c, d, short styles, d 1, thin growth stage of d, e, angularly bent oxeas, e 1, apices of e.