Ophiolepis biscalata, Mcknight, Donald G., 2003

Mcknight, Donald G., 2003, New brittle­stars (Echinodermata: Ophiuroidea) from New Zealand waters, Zootaxa 352, pp. 1-36 : 27-28

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https://doi.org/ 10.5281/zenodo.156750

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Ophiolepis biscalata


Ophiolepis biscalata   n.sp. Fig. 1 View FIGURE 1 : E, F.

Material examined: NIWA Stns J 662 (1); Z 10813 View Materials (1, damaged).

Depth Distribution: 670–1021 m.

Geographic Distribution: This species is recorded from Silent 1 and Rumble 5 Seamounts, north of the Bay of Plenty, North Island.

Description: Holotype, NIWA Stn J 662: disc diameter 16 mm, arms about 41 mm long. Disc circular in outline, mainly flat above, slightly sloping near low margin, flat below. Dorsal surface of disc covered with small, irregularly shaped overlapping plates; distal 2 / 3 of radial shields separated by a single larger plate or a single row of plates; plates are slightly larger in interradii. Radial shields short, rounded­triangular in outline, distal margin straight, extending inwards for about 1 / 4 disc radius, completely separated; small interradial plates extend across armbase, at outer end of radial shields. Ventral surface of disc covered with small overlapping plates or scales. Genital clefts entire and narrow, extending from distal margin of oral shield to margin, interradial margins more or less smooth. Oral shields elongate, clearly longer than wide, pointed proximally, slightly narrowed at commencement of genital slit, distal margin straight; madreporite slightly enlarged, more rounded. Adoral shields just meet within, extending to distal margin of oral shield or slightly beyond, widened in distal part. Oral plates have 5–6 distinct flattened papillae along side of oral slit, outer papilla is small, next is largest; all are subrectangular except for proximal 1–2, which are more pointed. A single pointed apical papilla at tip of jaw; all papillae are erect; teeth concealed.

Arms wider than high at base, gradually tapering, rounded on dorsal surface, almost flat below. Dorsal armplates in contact for most of arm; proximal plates much wider than long, in form of truncate triangle, widest near distal end, distal margin slightly concave, distally plates become simple triangles, longer than wide; and slightly separated; throughout arm, though more common near base, occasional plates are subdivided into 2 pieces. In proximal 1 / 4 of arm, most dorsal armplates have a small supplementary lateral piece, sharply pointed laterally, adjacent the lateral plates, beyond it is absent. Lateral armplates with 2 rounded, bluntly pointed armspines, about as long as segment length, placed near ventrolateral margin; occasional proximal plates have 3 such spines. Ventral armplates in contact for almost all of arm; plates are about as wide as long, distal margin slightly the wider, usually slightly notched; lateral margins excavate for tentacle­pore; proximal plates have straight proximal margin, but this develops a point distally. Tentacle­pore large, 2 tentacle­scales over most of arm, both flattened, pointed proximally, distally broadly rounded, outer scale usually the larger.

Colour: (Preserved specimen) dull uniform light brown above and below.

Etymology: The species name, biscalata   , refers to the two tentacle­scales.

Holotype: Deposited in the NIWA collection, Wellington, No. H­ 827 (Stn J 662).

Paratype: Deposited in the NIWA collection, Wellington, No. P­ 1379 (Stn Z 10813 View Materials ).

Remarks: These specimens appear referable to Ophiolepis   in having supplementary dorsal armplates, though the southern locality and considerable depth are atypical for this genus. It differs from O. nodosa Duncan   and O. rugosa Koehler   in lacking tubercular plates on the disc or dorsal surface of the arms. Ophiolepis cincta Müller & Troschel, 1842   , O. superba H.L. Clark 1915   , and O. unicolor H.L. Clark 1938   , lack these tubercles and have broad dorsal armplates, but have 5–8 armspines and shorter oral shields.

Of species known from the Atlantic Ocean, only O. pawsoni Thomas 1988   , appears related. It has similar, though thicker disc scales, but has circular thickened scales between the radial shields, a rounded oral shield about as wide as long, supplementary dorsal armplates are present over most of the arm, and both dorsal and ventral armplates have differing outlines.


National Institute of Water and Atmospheric Research