Chondrocladia (Meliiderma) turbiformis, Vacelet, Jean, Kelly, Michelle & Schlacher-Hoenlinger, Monika, 2009

Vacelet, Jean, Kelly, Michelle & Schlacher-Hoenlinger, Monika, 2009, Two new species of Chondrocladia (Demospongiae: Cladorhizidae) with a new spicule type from the deep south Pacific, and a discussion of the genus Meliiderma, Zootaxa 2073, pp. 57-68 : 59-60

Chondrocladia (Meliiderma) turbiformis sp.nov. ( Fig. 2–3 )

Material examined. Type material. Holotype NIWA 21357: NIWA Stn TAN0104/333, Pyre Seamount, Chatham Rise, -42.7183342°, 179.9095001°, 1075– 1008 m, R. V. Tangaroa , 20 April 2001.

Paratypes NIWA 21355: NIWA Stn TAN0104/152, Gothic Seamount, Graveyard seamount complex, Chatham Rise, -42.7298317°, 179.8903351°, 1130– 1000 m, R. V. Tangaroa , 18 April 2001; NIWA 21356: NIWA Stn TAN0104/153, Gothic Seamount, Graveyard seamount complex, Chatham Rise, -42.7324982°, 179.8984985°, 1076– 990 m, R. V. Tangaroa , 18 April 2001; NIWA 21358: NIWA Stn TAN0104/333, Pyre Seamount, Graveyard seamount complex, Chatham Rise, -42.7183342°, 179.9095001°, 1008–1075 m, R. V. Tangaroa , 20 April 2001; NIWA 21359: NIWA Stn TAN0104/397. Pyre Seamount, Graveyard seamount complex, Chatham Rise, -42.7163315°, 179.9114990°, 1050– 1000 m, R. V. Tangaroa , 21 April 2001.

Type Locality. Pyre Seamount, Chatham Rise, New Zealand.

Distribution. Pyre and Gothic seamounts in the Graveyard seamount complex, Chatham Rise, southeastern New Zealand.

Habitat. Attached to fragments of coral dredged from seamount, depth range 990 to 1130 m.

Description. Six fragmentary stipitate specimens, consisting of a roughly spherical body supported by a broken cylindrical stalk. Fixation base or rhizoids absent. Body 14 mm in diameter in the holotype, varying from 10 to 19 mm in the paratypes, fragmentary stalk 25 x 2 mm in the holotype, 10–30 x 1.2–1.9 mm in the paratypes. Body irregular in shape, covered with long, irregular thick expansions at the surface, up to 8 mm long. Stalk curved in most specimens, smooth, with some irregular swellings in NIWA21358. Color clear brown, more translucent in the stalk. Numerous whitish oval bodies, probably embryos, in the body of most specimens. In NIWA21357, putative embryos in various stages of development irregularly ovoid, 450–600 x 250–300 µm, some devoid of spicules, others containing immature stages of isochelae 2 or mature isochelae 2 irregularly arranged, without megasclere. No visible aquiferous system; living tissue poorly preserved.

Skeleton. Stalk made of tightly packed longitudinal slightly sinuous mycalostyles and substrongyles, including a few isochelae and sigmas, and a variable number of trochirhabds. Trochirhabds present uniquely along the shaft, dispersed or grouped in rosettes attached by the narrower end. In specimenNIWA21358, trochirhabds form an incomplete, poorly preserved sheath along the stalk, spicules tightly apposed on a single layer, perpendicular to the axis. Skeleton of the body made of radiating fascicles of mycalostyles, extending as an axis in the filaments. Irregular swellings of the stalk of NIWA21358 with a skeleton of irregularly arranged mycalostyles 1, substrongyles, isochelae 1 and trochirhabds.

Spicules. Megascleres ( Table 1 , Fig. 2 ). Mycalostyles 1 of the stalk and of the spicular axis of the body, most generally straight, non or feebly fusiform except in specimen NIWA21358 (for instance for a mycalostyle 1600 µm long, diameter 25 µm in head, 40 µm in middle), with a short point, 1000–1700 x 15–40 µm, up to 45 µm thick in NIWA21356; Mycalostyles 2, always rare, long and thin, often with a slightly inflated head, generally straight although sometimes curved near the point, possibly juvenile or ill-formed mycalostyles 1, 340– 1400 x 4–15 µm; Substrongyles and subtylostrongyles of the basal part of the stalk, not found in specimen NIWA21357, irregularly curved or faintly flexuous, the larger sometimes slightly curved and inflated, with intermediaries with mycalostyles 1, 260– 1288 x 12–30 µm, some short and thick (260 x 30 µm in NIWA21355). Microscleres ( Fig. 2 , 3 ). Anchorate isochelae 1, rare in the stalk, very abundant in the body, with narrow fimbriae and five or six teeth. Teeth short, rather thin and acerate (13–15 x 3–3.2 µm). Size 68–95 µm, shaft 5 µm in diameter; Anchorate isochelae 2, less numerous and apparently localized in embryos, with fimbriae larger than in isochelae 1 and five thin teeth oval or lanceolate (9 x 2 µm). Size 32–50.5 µm, shaft 2 µm in diameter; Sigmas, present in all specimens although rare in NIWA21355, C or Sshaped, with a 90° torsion, 30–50 µm; Trochirhabds, present in the stalk and inside the living tissue in the basal part of the body of all specimens, absent in the upper part of the body, sometimes with a rosette-like arrangement or in a single layered sheath along the stalk. Spicule made of a straight, slightly conical rhabd ending in a large, hemispherical bulge at the apex and in a smaller bulge at the thinner end. Rhabd bearing three, rarely two thick rings. Hemispherical upper surface of the two bulges covered with short, irregular spines or small buttons. Under surface of the bulges, surface of the rings and shaft nearly smooth, bearing only a few, irregularly dispersed small granules. Rings sometimes incomplete, with the margin irregularly crenulated or slightly verrucose. Very young developing spicules in shape of a rhabd with an inflated head, a long, narrow neck progressively inflating in a cylindrical shaft 5 µm in diameter, ending in a mucronate, round point. Rings appearing later as swellings of the shaft. Nearly mature spicules with rather smooth surfaces and a poorly developed third ring. Size: 30–50 µm, rings in the mature spicules 7–20 µm in diameter.

Etymology: Named for the spindle or whirl-shaped form of the characteristic trochirhabds (Latin, turbo, spinning top, disc).

Remarks: This species differs from the two other species of Chondrocladia with trochirhabds by having three annuli on the trochirhabds, instead of two in C. occulta ( Lehnert et al., 2006) and one in C. tasmaniensis sp.nov. (this paper). Unlike the two other species, the cover of trochirhabds is discontinuous on the stalk, forming a sheath only in places. This could be due to poor preservation, as this thin sheath is easily removed in places. The trochirhabds are also sometimes grouped in rosettes, and some of them are located inside the axis of the stalk. The fixation base is missing in all specimens, suggesting that the specimens were fixed on hard substrate by an enlarged base, and subsequently broken off. If the specimens were anchored in mud we could expect a rhizoid system to have survived on the base of the stalk. It is likely that shorter and thicker substrongyles would be present in the base in complete specimens, as it is frequently the case in cladorhizids attached to solid substratum.

Figures

FIGURE 2. Chondrocladia (Meliiderma) turbiformis sp. nov. A: Holotype (left) and paratypes NIWA 21356 (two specimens), NIWA 21355 and NIWA 21358. B. Megascleres; from left to right, mycalostyle 1, mycalostyle 2, two strongyles. C. Mycalostyle 1. D. Isochelae 1. E. Isochelae 2 from embryos. F: Sigma. G. Trochirhabds. H. Development stages of trochirhabds.

FIGURE 3. Chondrocladia (Meliiderma) turbiformis sp. nov. Longitudinal section through the stalk of specimen NIWA 21359, showing the axis of mycalostyles and substrongyles, trochirhabds isolated or grouped in vague rosettes.