Cryptosyringa membranophila Vacelet, 1979

Rützler, Klaus, Piantoni, Carla, Van, Rob W. M. & Díaz, Cristina, 2014, Diversity of sponges (Porifera) from cryptic habitats on the Belize barrier reef near Carrie Bow Cay, Zootaxa 3805 (1), pp. 1-129 : 22

Cryptosyringa membranophila Vacelet, 1979

( Figure 2 d)

Synonymy and references. Cryptosyringa membranophila Vacelet, 1979: 33 , figs. 1, 2; pl. I. Uriz (2002a): 111, figs. 2, 3.

Material. USNM 1191345, Forereef cave rock just east of Carrie Bow Cay, 26 m; K. Ruetzler coll. 22 May 1975.

External morphology. The tiny pyriform, off-white specimens (4.5 x 3 mm maximum dimensions), are attached to and penetrate leathery membranes at their thicker end. The membranes, which coat burrows in coral rock, are presumed to be remnants of boring polychaetes. The incurrent and exhalant openings are at opposite ends of the longer axis. Longitudinal inhalant-exhalant canals extend from the narrow end, where the ostia are located, to the sieve-like base that serves as the osculum.

Skeleton structure. Dichotriaenes are at the periphery, with a tangential cladome and the rhabdome directed inward. Tylotes/strongyles and oxeas are arranged in longitudinal and radial directions. Microscleres are concentrated in the ectosome (tylasters) and near the base (oscular region) of the sponge (oxyasters).

Spicules. Dichotriaenes with clads and rhabdome ending in rounded points or asymmetrical knobs. The overall diameter of the cladome is 240–360 (323) Μm, protoclads measure 40–50 (44) Μm, deuteroclads 90–180 (129) Μm, the rhabdome 590–820 (693) Μm in length; thickest diameters are 8–10 (9) Μm. Most diactines are strongyles, thickest in the center, but many have terminal swelling (tylostyles; some quadrilobate), and a few are modified to pointed ends (oxeas): 530–880 x 5–10 (703 x 8) Μm. Among the microscleres there are tiny tylasters, 8 –10 (9) Μm and larger oxyasters, 23–36 (30) Μm in diameter; the latter with a center that takes up 20–30% of the total diameter.

Ecology. Approximately 10 specimens were retrieved from burrows in dead, platy coral ( Montastraea annularis ) in a small cave in 26 m depth. The sponges are attached to chitinous membranes presumed to have been secreted by eunicid polychaetes that produced the burrows.

Distribution. Only known from the type locality ( Jamaica) and the present record ( Belize).

Comments. It is still unknown what causes the attraction of these sponges to the organic bore-hole coatings presumably secreted by polychaetes. Finding this species in Belize under the same conditions and in the same kind of habitat as the type material in Jamaica indicates that there is a still enigmatic ecophysiological process involved.

Figures

FIGURE 2. The most common cryptic habitats studied in the Carrie Bow Cay vicinity (measurements in parentheses are picture widths): a, lower surface of platy coral rock showing the characteristic red foraminiferan Homotrema rubrum, calcareous serpulid polychaete tubes, and two encrusting sponges, Clathria (Thalysias) venosa (left) and Clathria (Thalysias) curacaoensis (10 cm); b, wall inside a forereef framework cave, showing the massive Smenospongia cf. echina (yellow) and Topsentia bahamensis, and encrusting Clathria (Microciona) bulbotoxa (17 cm); c, ceiling of the drowned karst cave in the barrier reef lagoon near Columbus Cay, about 20 m away from the entrance (“ blue hole ”), showing cemented (mostly dead) serpulid tubes, a branching form of Geodia gibberosa (center) and a few knobby specimens of Gastrophanella cavernicola (far left and right; 20 cm); d, broken-up rock from a forereef cave bottom, showing deserted polychaete borings that are colonized by Cryptosyringa membranophila specimens (6 cm); e, broken-up coral rock showing chambers of excavating sponge Cliona cf. mucronata (7 cm); f, Queen conch (Strombus gigas) shell discarded by local fishermen are a common cryptic habitat on the shallow reef (the slot cut by machete near the apex (arrow) to remove the conch assures good ventilation inside the shell); this shell is colonized outside by Chondrilla caribensis, which occurs fully light exposed as well as in darkness (20 cm); g, peat cave (undercut) in the Twin Cays mangrove, the wall covered by Scopalina ruetzleri (80 cm).