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Sea-Stars (Echinodermata: Asteroidea) from "Eltanin" Cruise 26, with a Review of the New Zealand Asteroid Fauna

Order Paxillosida Perrier, 1884

Order Paxillosida Perrier, 1884

Suborder Diplozonina Spencer and Wright, 1966
Family Astropectinidae Gray, 1840
Subfamily Astropectininae Gray, 1840

Proserpinaster Fell, 1963
Proserpinaster neozelanicus (Mortensen)

Persephonaster neozelanicus Mortensen, 1925, p. 415, fig. 70; Fell 1952 p. 6; —, 1959, p. 131, fig. 5; —, 1960, p. 61.

Proserpinaster neozelanicus Fell, 1963 (a), p. 142; —, 1963 (b), p. 385, fig 2

Prosperinaster neozelanicus McKnight, 1967, pp. 292, 298.

Material Examined:

One specimen, Sta. 1846.

Size:

R/r = 123/30 mm.

Remarks:

The present specimen agrees well with previous descriptions.

Small specimens of this species could possibly be confused with Psilaster acuminatus Sladen, especially when superomarginal spines are present in the latter; probably they can best be distinguished by the abactinal paxillae which are brush-like in Proserpinaster and distinctly granular in Psilaster acuminatus.

Fell (1963, p. 142) proposed a new genus Proserpinaster, on the basis of the broadened interradial inferomarginal plates which are separated by fascioles, to receive the present species and three other Indonesian species.

Colour:

Bright pink.

Geographical Distribution:

Known only from New Zealand and the Chatham Islands.

Depth Range:

92–518 m.

Type Locality:

Unknown.

Location of Type:

Dominion Museum, Wellington, New Zealand. (Ech. 194).

Psilaster Sladen, 1885
Psilaster acuminatus Sladen

Psilaster acuminatus Sladen, 1889, p. 225, pl. 40, figs. 1, 2, pl. 42, figs. 7, 8; Clark, H. L., 1916, p. 32; —, 1923, p. 248; Mortensen, 1925. p. 274; Fell, s1958, p. 4; —, 1959, p. 131, fig. 13; McKnight, 1967, pp. 292, 298.

Material Examined:

32 specimens, St. 1847 (3); 1848 (27); 1849 (2).

Size:

R = 70–31 mm., average 49 mm.; r = 12–6 mm., average 10 mm.

Remarks:

This species has been well described previously. Sladen (1889, p. 227) records some specimens in which superomarginal spines are present for a short distance page 12along the arms; subsequent authors do not mention this. Of the 32 specimens in this collection, 14 (R/r averaging 47/10 mm.) are without any trace of superomarginal spines; 12 specimens (R/r averaging 52/11 mm.), have occasional, isolated superomarginal spines and 6 specimens (R/r averaging 52/11 mm. also), have an almost continuous row of small distinct superomarginal spines midway along the arms but these are absent proximally from the first 7–9 plates and distally near the arm tips. In other specimens examined by the author, superomarginal spines were present occasionally. Otherwise the specimens agree well with previous descriptions although as Mortensen (1925, p. 275) notes, Sladen's description of the inferomarginal plates is misleading. At least 6 specimens in the present collection, have regenerating arm tips.

Colour:

Dark pink to orange-pink abactinally, regenerating arm tips white; marginal plates yellow or pinkish-white, actinal surface creamy yellow and tube feet delicate pink.

Geographical Distribution:

New Zealand, Australia and ? South Africa (Australian and South African specimens are not available to the author for comparison, but from H. L. Clark's (1923, p. 248) description of South African material, there are differences).

Depth Range:

35–1757 m.

Type Locality:

"Challenger" Sta. 167, 39° 32′ S., 171° 48′ E., north-west of Port Hardy, New Zealand; 277 m.

Location of Type:

British Museum (Nat. Hist.).

Plutonaster Sladen, 1885
Plutonaster fragilis n.sp. (Fig. 1, c, d; Pl. 1, a, b).
Material Examined:

42 specimens, Sta. 1846.

Size:

R = 98–66 mm., average 82 mm.,; r=32–20 mm., average 26 mm.

Description:

Description based on specimen with R/r = 75/22 mm.

Disc large, compressed dorso-ventrally; arms short, tapering evenly to sharp tip protected by saddle-shaped plate.

Abactinal paxillae small, crowded, without regular arrangement except near arm edges where they form transverse rows. Plates oval or faintly lobed, paxillar trunk short with broad expanded head bearing from 10 (near arm margin) to 25 fine rugose spinelets. Occasional inconspicuous pedicellariae, formed by enlarged tips of 3 or 4 paxillar spines, present along arm margins.

Madreporite almost circular, compound, finely dissected, large (about 10 mm.), nearer edge than centre of disc; covering paxillae large, with up to 45 spinelets each.

Supermarginal plates tumid, rectangular, 35 or 36 extending from interradial angle to arm tip, forming distinct border to abactinal surface; plates covered with small spinelets similar to those of abactinal paxillae. Each plate with one, occasionally 2, enlarged, sturdy, tapering, broad-based spines. Plates separated by distinct fascioles lined with thin, blunt-tipped, flattened spines. Inferomarginal plates page 13corresponding to superomarginals, forming broad edge to actinal surface. Plates separated by deep fascioles and bearing generally one (occasionally 2 proximally) enlarged, broad-based tapering spines. Occasional incipient pedicellariae formed by enlarged and clavate heads of 3 or 4 spines, near superomarginals.

Actinal interradial areas extending for at least half length of each arm, plates in regular longitudinal rows, one plate corresponding to each adambulacral and 2 to each inferomarginal. Each plate (fig. c) with numerous short spines; interradially, generally a single (occasionally near oral plates 2) central, enlarged blunttipped spines. Many plates interradially, with distinct pedicellariae (fig. c) formed by enlarged and clavate heads of 3–5 spines.

Adambulacral plates (fig. d) with regular fringe of 9–11 furrow spines; one conspicuous, sturdy subambulacral spine similar to enlarged spines of marginal series, surrounded by number of smaller, spaced spines. Occasional incipient pedicellariae present on outer edge of plates adjacent to actinals.

Oral plates with 10–12 subequal, slender furrow spines and numerous shorter suboral spines arranged in more or less distinct longitudinal rows.

Ambulacral grooves deep, tube feet biserial without distinct sucking discs.

Variations:

Unfortunately much of the remaining material is damaged as the specimens deteriorate very quickly out of water. Most variation seems to occur in the number of actinal and inferomarginal pedicellariae which are always present but which may be few or numerous irrespective of the animals' size.

Remarks:

This new species is characterised by the large number of adambulacral and oral furrow spines and by the presence of abactinal, inferomarginal and actinal pedicellariae (it appears to be the only known species with inferomarginal pedicellariae). P. knoxi Fell from the Chatham Islands is similar but can be distinguished by its rather smaller disc, longer and more slender arms, fewer adambulacral furrow spines (7 or 8) and the lack of pedicellariae. The present species is similar to the North Atlantic P. bifrons Wyville Thomson but the presence of pedicellariae is distinctive; it can be distinguished from P. abyssicola Ludwig (Gulf of Panama) by the more numerous spines of the abactinal paxillae and the presence of generally only one inferomarginal spine.

Colour:

Disc centre white to pale yellow with orange or yellow arms; paxillae covering madreporite lighter than those adjacent; marginal plates orange, spines white. Actinal surface pale orange or yellow, always darker near edge; tube feet and actinostomial membrane orange.

Geographical Distribution:

Known only from the type locality, off the West coast of the South Island, New Zealand.

Depth Range:

1647–1693 m.

Type Locality:

"Eltanin" Sta. 1846, 43° 54′–43° 48′ S., 167° 43–167° 46′ E., off West Coast of South Island, New Zealand; 1647–1693 m.

Location of Type:

United States National Museum.

page 14

Suborder Cribellina Fisher, 1911

Family Porcellanasteridae Sladen, 1883
Porcellanaster Wyville Thomson, 1877
Porcellanaster caeruleus Wyville Thomson (Pl. 1, c-f).

Porcellanaster ceruleus Wyville Thomson, 1877, p. 378, figs. 97, 98.

Porcellanaster caeruleus Sladen, 1889, p. 134, pl. 20, figs. 1–7, pl. 20A, figs. 1–10; Clark, H. L., 1923, p. 239; Madsen, 1961, p. 126, figs. 22–24.

Material Examined:

6 specimens, Sta. 1837 (2); 1844 (1); 1846 (3).

Size:

R = 18–5 mm., average 11 mm.; r = 6–2 mm., average 4 mm.

Remarks:

The present specimens show considerable variation; however, these come within the limits described previously (Madsen, 1961). In several small specimens the apical appendage is well developed and paved with small overlapping porous plates; in the 3 larger specimens (Sta. 1846, R = 18—13 mm.) it is inconspicuous. The supermarginals of all these 3 larger specimens bear distinct spines and the abactinal spines of the disc are well developed and conspicuous in all but the interradial areas; actinally, the interradial areas are paved with plates (in small specimens these areas are naked except for a few, small, scattered, isolated plates near the margins). In one small specimen (Sta. 1837, R/r = 7/3 mm.) 3 straight pedicellariae are present abactinally, near the marginal plates in each interradius.

Colour:

Blue-grey.

Geographical Distribution:

World-wide, in deeper waters from Greenland to Antarctica.

Depth Range:

1158–6035 m.

Type Locality:

"Challenger" Sta. 45, south-east of New York, 38° 34′ N., 72° 10′ W.

Location of Type:

British Museum (Nat. Hist.).

Eremicaster Fisher 1905
? Eremicaster sp.
Material Examined:

One specimen, Sta. 1844.

Size:

R/r = 11/4 mm.

Remarks:

This specimen is much damaged, especially actinally, but the presence of 3 cribriform organs in each interradius suggests its inclusion in Eremicaster. It is conceivable that damage to the arms in life could result in abnormalities in development of the cribriform organs; if this is so in the present specimen, then it probably belongs in Porcellanaster. In each interradius there is one conspicuous, large central cribriform organ which is flanked by a small inconspicuous organ on either side. The latter are more or less V-shaped, with the open part of the V bordering the disc and the organs scarcely reach the inferomarginals. The abactinal surface, especially near the arm bases, is paved by pitted embryonic plates; centrally on the disc and extending interradially there are small, round or oval, isolated, tumid, conspicuous plates superimposed on the pitted plates which bear short spines interradially. page 15Distally, the one intact arm tip is protected by a saddle-shaped plate with 3 broken spines.

Colour:

Blue-gray.

Geographical Distribution:

World-wide including Antarctica but as yet not known from north of 60° N.

Depth Range:

750–7245 m.

Location of Specimen

United States National Museum.

Styracaster Sladen 1883
Styracaster horridus Sladen (Fig. 1, e; Pl. 1, g, h)

Styracaster horridus Sladen, 1889, p. 150, pl. 23, figs. 5–7, pl. 27, figs. 17–20; Madsen, 1961, p. 93, text-figs. 12–17, pls. 7, 8.

Chunaster scapanephorus Ludwig, 1907, p. 316; Madsen, 1961, p. 94.

Material Examined:

One specimen, Sta. 1844.

Size:

R/r = 44/8 mm.

Remarks:

The present specimen, although somewhat damaged, agrees well with the type description. The marginals join medially at about the fourth plate and there are 9 or 10 strong spines present to the arm tips; the abactinal paxillae are composed of from 3–7 short spines. Only 7 oral furrow spines are present and although the plates are damaged there appears to have been one suboral spine situated midway along the median suture. Both the adambulacral plates and the actinal plates (fig. e)—the latter with from one to 3 small inconspicuous granules—are similar to those described for the type material.

Colour:

Abactinal surface—disc cream, marginal plates and spines white, cribriform organs pale yellow; actinal surface—interradially, grey-blue (probably due to ingested mud) with adambulacral and oral plates white; faint pink ?gonads in 2 interradi. Tube feet and actinostomial ring yellow.

Geographical Distribution:

Northern Hemisphere—Bay of Biscay south to Gulf of Guinea and from the Indian Ocean; south of the equator it has been collected from near Madagascar, Sumatra, the Kermadec Trench and, this report, at 46° S.

Depth Range:

2470–5610 m.

Type Locality:

"Challenger" Sta. 346, 2° 42′ S., 14° 41′ W., Eastern Atlantic.

Location of Type:

British Museum (Nat. Hist.).

Family: Benthopectinidae Verrill, 1894
Benthopecten Verrill, 1884
Benthopecten pikei H. E. S. Clark var. australis var. nov. (Fig. 1, f, g; pl. 1, i, j).
Material Examined:

2 specimens, "Eltanin" Sta. 1846.

page 16
Size:

Larger specimen R/r = —150/20 mm.; smaller specimen (arms broken) R/r = -35/5 mm.

Remarks:

Both the present specimens differ from B. pikei in having more numerous (3–6) spines (fig. f) on the abactinal plates of the disc and from 4–6 small, very thorny spines on the arm plates which give a distinctly "hairy" appearance, especially proximally. In B. pikei there are seldom more than three spines on the abactinal plates and these are reduced to one distally; the distinct V-shaped arrangement of abactinal plates seen in B. pikei is absent in both the present specimens. In the larger of the 2 specimens discussed here, the enlarged central spines of the disc are more numerous, thicker and almost bulbous when compared with similar spines in B. pikei; this difference can probably be attributed to the larger size of the present individual. Another difference is in the unpaired superomarginal plate (fig. f). In the larger specimen there is a single enlarged spine surrounded basally by a half circle of 6 or 7 smaller spines with scattered spinules basally; in B. pikei only one unpaired plate bears an enlarged spine (the others may have been lost through injury) and there is no distinct half circle of smaller spines. The curious pectinate pedicellariae shared between the adambulacral and inferomarginal plates (fig. g.) (one such pedicellaria is present in the holotype of B. pikei) are very distinct in the larger of the 2 present specimens, especially midway along the arms; these pedicellariae consist of from 4–7 small, slender inferomarginal spines which interlock with similar adambulacral spines; no pedicellariae are present in the smaller specimen.

The smaller specimen lacks a conspicuously enlarged second inferomarginal spine on most of the plates, the adambulacral furrow spines are 6 in number and there are generally only 2 subambulacral spines on any plate; the actinal plates are few with an indication of pedicellariae in 2 interradii only and there are 4 or 5 oral furrow spines.

Both B. pikei and the new variety can be distinguished from B. munidae H. E. S. Clark (in press) by the fewer oral furrow spines and differences in the armature of the inferomarginal plates.

Colour:

Large specimen red, smaller specimen "lighter".

Geographical Distribution:

Known only from "Eltanin" Sta. 1846, 43° 54′–43° 48′ S., 167° 43–167° 46′ E., off the West Coast of the South Island of New Zealand.

Depth Range:

1647–1693 m.

Locality:

"Eltanin" Sta. 1846, 43° 54′–43° 48′ S., 167° 43′–167° 46′ E., off the West Coast of the South Island, New Zealand; 1647-1693 m.

Location of Specimen

United States National Museum.

Pectinaster Perrier, 1885
Pectinaster mimicus (Sladen) (Pl. 2, a-d).

Pontaster mimicus Sladen, 1889, p. 48, pl. 6, figs. 1, 2, pl. 7, figs. 5, 6.

Pectinaster mimicus Ludwig, 1910, p. 449; Fisher, 1919, p. 182, pl. 49, fig. 1.

Material Examined:

81 specimens, Sta. 1846.

page 17
Size:

R = 68–11 mm., average 43 mm.; r = 12–13 mm., average 7 mm.

Remarks:

This species has been well described previously and is highly variable as Fisher (1919, p. 183) shows. The present specimens, when compared with 2 specimens of P. mimicus (Sladen) from Macassar Straits (U.S. National Museum, 53256) differ in having generally more abundant and stouter pedicellariae, especially abactinally, and in having rather fewer abactinal spines surrounding enlarged central spines; other differences include the more robust and stouter marginal spines and the rather more dense covering of the marginal plates—all these characters are very variable and all degrees are to be seen in the material at hand.

The accompanying table shows the variations observed in 12 specimens:

TABLE: Variations in 12 specimens of Pectinaster mimicus (Sladen)

TABLE: Variations in 12 specimens of Pectinaster mimicus (Sladen)

This table is interesting when compared with that given by Fisher (1919, p. 183) as both the number of proximal adambulacral furrow spines and the number of adambulacral plates corresponding to the first 10 inferomarginals seem more stable in the present material.

page 18

Several specimens in the present collection are of particular interest. In one specimen, R/r = 34/7 mm. the enlarged central spines of the abactinal paxillae are missing from all but a few paxillae; abactinal pedicellariae are numerous, especially centrally on the disc; between the 2 most proximal superomarginals there is a single, large, pectinate pedicellaria and indications in several interradii of flanking pedicellariae; similar pedicellariae may be present between the inferomarginal plates, and occasionally indistinct pedicellariae are present between the supero—and inferomarginal series; actinal pedicellariae are few and indistinct and none is present between the inferomarginals and adambulacrals; there are 5–7 adambulacral furrow spines, one enlarged subambulacral spine and the oral plates have a furrow series of 7 or 8 spines.

In another specimen, R/r about 45/8 mm., the enlarged subambulacral spine is very sturdy and slightly recurved towards the arm tip; it is accompanied by a second slightly shorter and finer, but similarly recurved, spine.

Small specimens (R = 25 mm. or less) appear distinctly "hairy" abactinally, as the enlarged central spines of the abactinal paxillae are particularly long, especially near the papulae; abactinal and intermarginal pedicellariae are often absent. In one specimen, R/r = 24/4 mm., one arm is forked, probably due to an injury, the fork beginning about one quarter of the way from the base of the arm and the ambulacral groove also forks.

Ten specimens were dissected; in all the gonads were interradial in position and well developed; in one specimen (R about 60 mm.) a branching copepod was present overlying the ambulacral plates and extending from the mouth well into the base of one arm; this arm was slightly broader and disfigured.

Colour:

Abactinal surface ranges from pale pink (R = 25 mm. or less) to darker pink, papularia cream or white; actinal surface dark pink, tube feet yellow-orange, actinostomial membrane grey-yellow.

Geographical Distribution

Known from the Philippines and Indonesian area and possibly also from the Laccadive Sea and, this report, off the West Coast of the South Island of New Zealand.

Depth Range:

692–1693 m.

Type Locality:

"Challenger" Sta. 191, 5° 41′ S., 134° 04′ 30″ E., Arafura Sea.

Location of Type:

British Museum (Nat. Hist.).