Oceanapia carotta (Schmidt, 1870)

Figures 28 a–e

Rhizochalina carotta Schmidt, 1870: 36, pl. IV fig. 2; Topsent, 1920: 4.? Rhizochalina fibulata Schmidt, 1880: 76 .

Oceanapia carotta; De Laubenfels 1936: 72.

Oceanapia oleracea; Van Soest 1980: 89, pl. XIV fig. 2, text-fig. 33.

(?Not: Rhizochalina oleracea Schmidt, 1870; nec sensu Wilson 1902, De Laubenfels 1947, Wells et al. 1960, Little 1963)

Material examined. RMNH Por. 6300, Suriname, ‘ Luymes O.C.P.S. ’ Guyana Shelf Expedition, station K101B, 7.3783°N 54.3583°W, depth 93 m, rectangular dredge, 17 April 1969 .

Description. (Fig. 28 a) About ten small rounded specimens, 1–2 cm in diameter and some fragments of larger fistules, 4–5 cm long, up to 1 cm in diameter, with branching apices. Color pinkish light brown.

Skeleton. Ectosomal skeleton of the main body consists of intercrossing single oxeas forming a feltwork-like skin. That of the fistules (Fig. 28 b) is a double layered single spicule reticulation supported by long subectosomal spicule tracts. The choanosomal skeleton of the main body (Fig. 28 c) is an irregular system of very thick tracts, 120–180 µm in thickness (15+ spicules in cros section) inbetween which is a confused mass of single spicules.

Spicules. (Figs 28 d–e) Oxeas, sigmas.

Oxeas (Fig. 28 d), curved, abruptly pointed, in a large size range, but no clear spicule categories, 105– 180 –241 x 4 – 8.1 –11 µm.

Sigmas (Figs 28 e), symmetrical, shallowly incurved, in a large size range, 15– 23.1 –33 µm.

Distribution and ecology. Guyana Shelf, Florida? (no locality known), Barbados?, Puerto Rico, Brazil?, muddy sand bottoms at 72–93 m depth.

Remarks. The possession of large numbers of sigmas conforms to Topsent’s (1920) redescription of Rhizochalina carotta . The size of the present specimens and fragments is here interpreted as juveniles, because Schmidt’s illustration (1870, pl. IV fig. 2) is of a much larger individual. O. carotta is here revived, from a suggested junior synonymy with Oceanapia oleracea (Schmidt, 1870), which ignores the importance of the presence of microscleres (e.g. Van Soest 1980). The only author who so far studied the type material of both species, Topsent (1920), listed sufficient differences to throw doubt on this synonymy.

Schmidt’s (1880) Rhizochalina fibulata from Barbados is a possible synonym of this species, as he mentioned the presence of numerous sigmas. The specimen was collected at considerable depth, 518 m.