Echinoderms from Southern New Zealand
Amphiura heraldica sp. nov. (Figures 5 to 7)
- Dimensions: R, 8·0 mm.; r, 2·9 mm.; ratio R/r, 2·8.
Amphiura heraldica sp. nov.
Fig. 5.—Aboral view. Fig. 6.—Adoral view. Fig. 7.—Lateral view of arm-segment.
Figs. 5 and 7 to scale at left; Fig. 6 to scale at right.
Abbreviations: A, adoral plate. D, upper arm-plate. DC, dorso-central primary plate of disc. G, genital cleft. I, primary interradial plate of disc. L, lateral arm-plate. O, oral shield. PL, oral plate. R, primary radial plate of disc. S, radial shield. TE, tentacle-scale. V, lower arm-plate.
Arms: upper arm-plates as broad as long, subquadrate, each with a convex distal border overlapping upon the next plate, all broadly contiguous. Lateral plates meeting neither above nor below, each bearing four, short, stout, subequal spines. Lower arm-plates similar to upper arm-plates, Save for the first one, which is more elongate. Tentacle-pores large, each having one large elliptical flat page 18 tentacle-scale, which is borne by the corresponding lower arm-plate. The pore itself is excavated within the lateral plate, and does not encroach much upon the margin of the lower plate.
Colour in spirit, white.
Type locality: Discovery station 2733, Chatham Rise, west of Chatham Islands, 30 metres, November 4, 1950; a single specimen.
Holotype: the unique specimen is in the Zoology Museum, Victoria University College.
The species is peculiar (amongst amphiurids) in respect of the large primary plates. The disc presents the aspect of an early post-larval stage, though its size is much larger than expected, and the arms present mature characters. It is, nevertheless, quite possible that this ophiuroid is a juvenile stage of some large species; but its distinctive features forbid our referring it to any known species.