Paratelecrinus telo, Messing, Charles G., 2013

Messing, Charles G., 2013, A revision of the genus Atelecrinus PH Carpenter (Echinodermata: Crinoidea), Zootaxa 3681 (1), pp. 1-43 : 31-33

Paratelecrinus telo new species

Figure 13 b

Holotype. NW Madagascar: MNHN IE- 2012-846, MIRIKI cruise, CP-3284, off Baie de Mahajamba, 14°51'S, 46°59'E, 236–297 m, 13 July 2009.

Diagnosis. A species of Paratelecrinus with extremely shallow V-shaped interradial notch in centrodorsal base and cirri in 15 columns (3 per radial area); centrodorsal base barely projecting interradially, if at all; peripheral sockets large (to 1.1 mm tall); IBr2 and IIbr1–2 with moderate synarthrial swelling; lateral margins of Ibr1 distinctly concave; Iax2 with short triangular distal angle.

Description. Centrodorsal conical, tapering from base; basal diameter 4.7 mm; HD 1.1; interradial margin barely projecting, with extremely shallow V-shaped excavation; interradial swellings barely present; radial margin almost straight. Apex rounded, smooth. Sockets in 15 crowded columns, 4–5 lateral and 3–4 midradial, three per radial area, not separated interradially; largest peripheral sockets to 1.1 mm tall; socket tubercles moderately developed.

Cirri LXIII, few remaining all broken; 3–4 proximal cirrals short; following segments increasing in length and becoming flattened, with LW 2.9 by c7.

Externally visible portion of basals straight or gently arched, separated from centrodorsal by thin but distinct suture, slightly swollen interradially and filling slight V-shaped excavation in centrodorsal margin, much narrower and tapered laterally. Radials short, crescentic; distal margin very shallow; WL 4.4; profile>90°.

Remaining ray length ~ 80 mm. IBr2 and IIbr1–2 with moderately developed, narrow synarthrial tubercles. Ibr1 wider than long, with distinctly concave lateral margins; distal margin shallowly V-shaped; WL 2.4. Iax2 hexagonal (almost rhombic) with short, concave and diverging lateral margins; distal angle acutely triangular; WL 1.3. IIbr1 with exterior margin longer and slightly concave; WL 2.3; interior margins of adjacent pair attached with ligament. IIbr2 quadrate or triangular, wider exteriorly, with weak exterior ridge; WL 1.5. IIbr3+4 longer and slightly flattened interiorly; WL 1.4; diameter 3.1 mm. IIbr5 almost triangular, flattened exteriorly; WL 2.4. WL of IIbr6+7 1.5. Following brachials strongly wedge-shaped, with moderately developed alternating articular tubercles; distal edge smooth, slightly raised; WL 2.3; brachials becoming proportionately longer distally. Distal brachials triangular; WL 1.5–1.7. Syzygies at 3+4, 6+7, 9+10, 12+13 (10+11 on one arm; 14+15 following 12+13 on another); following syzygies separated chiefly by 3–4 muscular articulations (less often 2, 5 or 6; at least 7 at the distal end of one remaining broken arm).

P1 on IIbr13 through IIbr19 on different arms. P4 almost complete, of 18 segments, 5.4 mm long; first pinnular short; second about as long as broad and narrower distally; third and following pinnulars longer than wide, LW 1.3, becoming 2.0 in mid-pinnule and 3.0 distally; middle segments slightly flattened and slightly wider distally; distal segments with expanded ends.

Distribution. Known only from the type locality: off Baie de Mahajamba, NW Madagascar, in 236– 297 m.

Etymology. The specific epithet, telo , means “three” in Malagasy, the national Austronesian language of Madagascar, and refers to the three columns of sockets in each radial area.

Remarks. Paratelecrinus telo resembles P. c on if e r in having 15 crowded columns of cirrus sockets and a Vshaped interradial notch in the centrodorsal base. However, it differs in several respects. The cirrus sockets are larger and fewer, although the centrodorsal is larger than in either specimen of P. c o n i f e r. The Ibr1 ossicle has distinctly concave lateral margins, giving it an hourglass shape; the distal angle of the axil is short and triangular instead of parallel-sided with a truncated tip, and the synarthrial tubercles are weaker and broader than in P. conifer . P. telo was also collected at a much shallower depth than P. c o n i f e r (236–297 m versus a possible range of 708– 1479 m).

Figures

FIGURE 13. Centrodorsal and ray bases in lateral view. a. Paratelecrinus laticonulus new species, holotype, MNHN IE- 2012 - 845. b. Paratelecrinus telo new species, holotype, MNHN IE- 2012 - 846. Scale bars: 1 mm.