Deep-Sea Echinoderms of New Zealand
Order Temnopleuroida — Family Temnopleuridae
Temnopleurus L. Agassiz, 1841
"Temnopleurus reynaudi" Agassiz.
- Agassiz, A., 1881. Challenger Echinoidea, p. 107.
Material Examined: None.
Recorded from Challenger Station 166, in 275 fathoms, 199 miles north-west of Cape Farewell. This record needs investigation.
Pseudechinus Mortensen, 1903
Pseudechinus huttoni Benham
- Benham, W. B., 1908. Ann. Mag. Nat. Hist. 8, p. 104.
Material Examined: Nine specimens from deep water, as under: 250–300 fathoms, off E. Otago, Dom. Mus. Station B.S.191, 7 specimens; 120 fathoms, off E. Otago, edge of Canyon A, Dom. Mus. Station B.S.189, 2 specimens.
The species has previously been recorded from shelf stations.
Pseudechinus flemingi sp. nov. Plate 3, Fig. A (holotype), B; Plate 5, Fig. a, paratype.
Diagnosis: Test hemispherical, the oral side rather flattened in the adult stage. Primary ambulacral tubercles contiguous throughout the ambulacrum; enlarged secondary tubercles form a vertical series adradial to the primaries, but these tubercles are much smaller than the primaries. Primary interambulacral tubercles not contiguous; enlarged secondary tubercles lie on either side of the primary, on the admedial side about 2 larger ones and 2 or 3 smaller ones, on the adradial side 2–6 usually arranged in horizontal series of 2 or 3, either one series or two such series occurring on alternating plates. The miliary tubercles are scattered thinly on the surface, but around the primary tubercle they form linear series, which are feebly united by sculptured ridges into a radiating pattern of spokes. On immature specimens a similar pattern is seen investing the primary tubercle of each ambulacral plate also, but this later disappears (compare Figs. A and C, Plate 5). Oculars all exsert. Primary spines 20 to 30 mm long.
Holotype: Test h.d. 52 mm, ht. 29 mm, in the Dominion Museum, Wellington.
Material Examined: Over 300 specimens (but mostly juveniles, many of them broken) from the following deep-water stations: 250–300 fathoms, Canyon B, off east Otago, Dom. Mus. Station B.S.191, 16/8/1955, holotype specimen and one other smaller individual; 330 fathoms, Station 41. Chatham Islands 1954 Expedition, about 300 specimens; 260 fathoms, Station 52, Chatham Rise, Chatham Islands 1954 Expedition, 5 specimens; 220 fathoms, Station 6, Chatham Rise, Chatham Islands 1954 Expedition, 5 specimens; also other material from 30 to 94 fathoms from Mernoo Bank and Station 29, in the Chatham Islands area.
Colour in life (and in spirit), the spines a brilliant orange-red, or deep salmon tint, with white tips. These are normally so densely matted as to obscure the underlying test but this, when denuded, is seen to be a rich rose-red with paler rose tubercles. The species is the most brilliantly coloured echinoid so far discovered in the New Zealand fauna, and is much brighter than Pseudechinus albocinctus (Hutton), a species which it otherwise much resembles.
Remarks: In the form of the test, the general preponderance of red colours, the white-tipped spines, and the arrangement of the tubercles in vertical and horizontal rows, Pseudechinus flemingi agrees closely with P. albocinctus. The two species are otherwise very different in appearance because the spines in albocinctus, though white-tipped, do not exceed 12 mm in length, and do not obscure the test, and their dull reddish-brown colour contrasts with the brilliant orange-red or deep salmon colour of flemingi. Obvious differences in the denuded test are the absence of the radiating sculpture from albocinctus, and the presence of weak crenulation on the primary tubercles of albocinctus. In the adult stage flemingi also presents weak admedian grooves on aboral interambulacral plates. No other species of Pseudechinus is at all closely related.
The presence of the weak radial sculpture and the admedian interambulacral grooves is a Temnopleurid character not hitherto reported from any species of Pseudechinus, and provides welcome evidence that the genus is correctly placed in the family Temnopleuridae. It is desirable to state here, however, that a careful examination of very young specimens of Pseudechinus albocinctus and Pseudechinus novaezelandiae from South Island stations has revealed faint traces of such radiating sculpture on the test plates. This disappears long before maturity is reached.
Pseudechinus flemingi occurs in Castlecliffian (Pleistocene) sediments near Wanganui, and has been known to me for some time through specimens collected by Dr. C. A. Fleming of the New Zealand Geological Survey. The fortunate discovery of living examples enables a recent specimen to be selected as the holotype.