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Deep-Sea Echinoderms of New Zealand

Family Astropectinidae

Family Astropectinidae

Astropecten Gray, 1840

Astropecten primigenius Mortensen
  • Mortensen, Th. 1925. Vid. Medd. dansk. naturh. For., 79, p. 272–4, Figs. 2–3, Pl. XII, Figs. 1–2.

Material Examined: Six specimens, from the following stations—250–300 fathoms, Canyon B, off east Otago, Dom. Mus. Station B.S.191, 1 specimen; 150 fathoms, Cook Strait, VUZ Station 98, 2 specimens; 105 fathoms, Mernoo Bank, Station 1, Chatham Island Exped. 1954; 61 fathoms, Mernoo Bank, Station 2, 2 specimens.

Mortensen's type was from 30 fathoms (north of Cuvier Island). The species has not hitherto been taken from deep water.

Astropecten dubiosus Mortensen
  • Mortensen, Th. 1925. Vid. Medd. dansk. naturh. For., 79, p. 269–72, Fig. 1, Plate XII, Figs. 3–4.

Material Examined: 1 specimen taken by the Alert, 113–120 fathoms, off Mayor Island, Bay of Plenty, Dom. Mus. Station B.S.208.

The specimen resembles the holotype, but is a little larger, R 40 mm, r 9 mm. It exhibits the same features as those which distinguished the holotype from Astropecten imbellis Sladen, so that Mortensen's belief that the two species are distinct seems to receive confirmation.

Astropecten sp.

A young individual R 6 mm from 400 fathoms, off Mayor Island, Dom. Mus. Station B.S. 210, is insufficiently developed for identification. The terminal plate carries three prominent spines, much more robust than any developed on the marginal plates. The record seems to imply the existence of one other species of Astropecten in New Zealand abyssal waters.

Psilaster Sladen, 1885

Psilaster acuminatus Sladen

  • Sladen, W. P., 1889. Rpt. on Asteroidea. Challenger Sci. Rslts., Zoology, 30, p. 225, Pl. 40, Figs. 1–2.

Material Examined: 32 specimens from the following localities: 430 fathoms, Cook Strait, VUZ Station 97; 380 fathoms, Cook Strait, VUZ Station 100, 10 specimens; 380 fathoms, Cook Strait, VUZ Station 96, 1 specimen; 200–250 fathoms, Cook Strait, VUZ Station 10, 1 specimen; 270 fathoms, off Mayor Island, Bay of Plenty, Dom. Mus. Station B.S.209, 1 specimen; 100–150 fathoms, Cook Strait, VUZ Station 15, 1 specimen; 113–120 fathoms, off Mayor Island, Bay of Plenty, Dom. Mus. Station B.S.208, 3 specimens; 124 fathoms, Bay of Plenty, NP Station 6, 13 specimens.

Remarks: The species was originally taken by the Challenger at Station 167, in 150 fathoms, north-west of Stephen's Island, and also off eastern Australia in 950 fathoms, and off South Africa, depth not stated. It is present in the Chatham Islands. page 5Expedition collections, but from shelf stations only; other specimens from the Cook Strait shelf have previously been recorded (Fell, 1952, p. 6).

Plutonaster Sladen, 1885

The genus, not previously recorded from New Zealand or Australia, is characterized as follows: Disc large, the intermediate actinal plates in several series, of which the innermost continue to about the middle of the arm. Marginals of both series well developed. Furrow spinelets forming a comb. No pedicellariae. Madreporite covered by paxillae.

Plutonaster knoxi sp. nov. Plate 1, Fig. C, holotype.

Diagnosis: Each marginal plate of both series carries one prominent, robust spine, this spine being surrounded by small spiniform granules. Adambulacral armature comprising a furrow-comb of about 8 uniform spines, outside of which is a single large subambulacral spine. Actinal intermediate plates carrying 1–3 large spines, in addition to a general coating of small spinules.

Material Examined: About 30 specimens (some of them greatly damaged) from the following localities: 330 fathoms, Station 41, Chatham Islands 1954 Expedition; 61 fathoms, Station 2, Mernoo Bank. Chatham Islands Expedition.

Remarks: This notable addition to the New Zealand fauna is one of the interesting discoveries of the expedition in 1954 led by Mr. George Knox. The full description, with photographic half-tone illustrations, will appear in the official report of the Chatham Islands Expedition. As can be seen from the diagnosis, the species resembles the North Atlantic Plutonaster bifrons (Wyville Thomson) and, like it, is distinguished from other species of the genus by having only a single large spine on each marginal plate of both series. The adambulacral armature also resembles that of P. bifrons. The two species are distinguished, however, by the armature of the actinal intermediate plates. In P. bifrons the actinal intermediate plates carry in addition to minute spinules, a single large spine, whereas in P. knoxi there are from one to three large spines, these spines intergrading into the coating of spinules in the case of the distal intermediate plates

Holotype: In the Canterbury Museum, R 105 mm, r 33 mm.

Persephonaster Alcock, 1891

Persephonaster neozelanicus Mortensen

  • Mortensen, Th. 1925. Vid. Medd. dansk. naturh. For., 79, p. 415, Fig. 70.

Material Examined: Five specimens from the following archibenthal stations—155 fathoms, Station 40, Chatham Islands 1954 Exped., 2 specimens; 150 fathoms, Cook Strait, VUZ Station 98, 2 specimens; 100 fathoms, Mernoo Bank, Station 1, Chatham Islands Expedition, 1 specimen.

Remarks: The species is very common on the Cook Strait continental shelf, from 40 fathoms and deeper (see Fell, 1952), but has not hitherto been taken in deep water. It would appear to be a typical shelf species which occasionally lives on the upper fringe of the continental slope. It seems unlikely that the species will be found in the abyssal fauna.

Dipsacaster Alcock, 1893

Although recorded from Australia (on the basis of a single individual) Dipsacaster has not hitherto been taken in New Zealand waters. The genus may be characterized briefly as follows: The margin of the ray defined by the inferomarginals, which project beyond the superomarginals. Actinal intermediate areas large, crossed by fasciolar grooves. No pedicellariae. Madreporite large, covered by paxillae.

page 6
Dipsacaster magnificus (H. L. Clark)
  • Lonchotaster magnificus Clark, H. L., 1916. Endeavour Rpt., p. 30, Pl. 6; Dipsacaster magnificus Fisher 1919. Bull. 100, U.S. Nat. Mus., 3, p. 150.

Material Examined: 25 specimens taken by Mr. F. Abernethy, honorary collector to Victoria University Zoology Department, at a depth of 55–63 fathoms in Cook Strait, 10 miles E. by S. of Cape Campbell. Colour in life, salmon-pink above, marginals paler salmon, underside cream.

Remarks: The holotype, hitherto unique, was taken by the Endeavour in the Great Australian Bight between 80–100 fathoms. The discovery of a relatively large population on the Cook Strait shelf, only a few miles from an area which had previously been trawled extensively, was a considerable surprise. Although D. magnificus has not yet been taken in deep water off New Zealand, it should probably be regarded as a deep water species, in view of its distribution. Like Psilaster, Gorgonocephalus, and other genera with a comparable range, it may well be an archibenthal type which occasionally ascends the slope to the continental shelf, provided the distance is not great.