Tuatara: Volume 7, Issue 3, June 1959
Starfishes of New Zealand
Starfishes of New Zealand
Starfishes and brittlestars are anatomically very similar and were formerly grouped together in a single class, the Stelleroidea, which included all star-shaped echinoderms. This simple classification, which was still in use in 1900 (when Gregory employed it in Lankester's Treatise of Zoology) was subsequently displaced by another, in which the starfishes (Asteroidea) and brittlestars (Ophiuroidea) were elevated to rank as distinct classes. The change was introduced on the grounds that embryological investigations suggested that asteroids were more closely related to holothuroids, since their larvae were similar, whereas ophiuroids had larvae which resembled those of echinoids. This view, although still maintained by Hyman in 1955. is no longer acceptable to many students of echinoderms. Fossil studies have shown that it is extremely unlikely that asteroids are more closely related to holothurians than to ophiuroids, or that ophiuroids could be more closely related to any known echinoids than they are to asteroids. Indeed, it can hardly be disputed that both asteroids and ophiuroids descend from common Palaeozoic ancestors which are now known to us -- namely, those star-shaped forms called Somasteroidea. Thus the larval evidence must have been misinterpreted, and requires reassessment.
After a lifetime of more than fifty years devoted to the study of fossil echinoderms, W. K. Spencer (Phil, Trans., 1951) set out in his last paper a new classification of the star-shaped echinoderms; in it, he revives the older grouping Stelleroidea, ranking it as a single class, and including in it three subclasses, two of them corresponding to the familiar asteroid and ophiuroid groupings, the third one comprising the Somasteroidea. This treatment has been adopted in the Anglo-American Treatise of Paleontology, now in preparation by a group of specialists, and probably will remain standard for some time to come. It may be noted that these authors prefer to use the name Asterozoa instead of Stelleroidea, parallelling another assemblage of echinoderms termed the Echinozoa. Diagnoses of the three groups of Asterozoa are too technical for presentation here but the following notes may serve to illustrate their character:
Class: ASTEROZOA— Free-living echinoderms with a depressed, stellate body; the ambulacral skeletal plates lie internally with respect to the radial ambulacral vessels; the madreporite is externally visible, but is not incorporated into any system of apical plates.
- Subclass (1): SOMASTEROIDEA— Extinct forms with no ambulacral groove, and with the arms barely differentiated in any way from the rest of the body; probably ‘ suspension-feeders ‘, i.e. stationary animals resting upon thepage 128
- sea-floor, depending for food upon the plankton-shower or upon the organic content of the uppermost layer of the sea-bed, the food particles being swept into the mouth by centrally directed water-currents; Lower Ordovician onward, probably ancestral to the two following subclasses.
- Subclass (2): ASTEROIDEA— Carnivorous or detrital-feeding forms, usually with rather stout arms which are not sharply demarcated from the centre of the body, and with an open ambulacral groove traversing the lower side of each radius; alimentary organs, and often also the reproductive organs, usually extending into the arms; food seized by the arms or engulfed into the everted stomach; Palaeozoic to present time.
- Subclass (3): OPHIROIDEA— Selective detritus-feeders, usually with a disc-shaped central body from which radiate the long, clearly demarcated arms; earlier types had an open ambulacral groove, like that of asteroids, whereas later types and all extant forms have the groove closed over and reduced to an internal canal; alimentary and reproductive systems usually confined to the disc; Palaeozoic to present time.
The foregoing paragraphs have referred to the general systematic position of starfishes. The following are some notes on the habits and ecology of starfishes, and their relation to other animals.
Starfishes usually creep about the sea-bed with the aid of their tube-feet. No swimming forms have yet been recorded. Those species which have suctorial tube-feet are able to climb and descend obstacles with their aid, and capture food. A number of genera have peculiar peg-like tube-feet (Fig. 2A), without suckers; they usually occur on submarine mud-banks, where they seem to use their tube-feet as oars or as stilts perhaps— I imagine them as tottering or paddling through the semi-fluid, slimy mud.
Although starfishes cannot see, since they have no eyes, they are able to detect light-fluctuations with the aid of a photosensitive eye-spot at the outer end of the ambulacral groove where it reaches the tip of the arm. Starfishes cannot be said to ‘ hear ‘, though they evidently detect the grosser vibrations often associated with sound. At the tip of the arm are some special tube-feet in some starfishes, which are held erect when the animal is active, and probably serve as taste-organs (chemoreceptors).
The sex of a starfish is seldom obvious without dissection, but in those forms which carry or brood the young, the female can be recognised during the breeding season (see Fig. 42). Their breeding habits are very varied. Apart from brood-protecting forms such as Calvasterias in New Zealand littoral waters, there are deep-sea forms such as Pteraster (Fig 28) with a dorsal brood-chamber developed on the upper side, provided with a water-conditioning system not unlike the water-circulatory system of a sponge, and having a large central osculum for the outflow of the water-current. One Greenland genus, Leptychaster, somehow contrives to hatch its eggs inside its stomach without accidentally digesting them. Many starfishes have free-swimming larval stages, others lay yolky eggs which undergo a direct development.page 129
Starfishes are probably short-lived animals with a life-span of only a few years. Some, at least, are known to be sexually mature after one year, though growth continues for about four years. Some kinds can regenerate lost arms; Luidia (Fig. 7) fragments upon even gentle handling, and must spend much of its life regenerating its lost members, to judge by the unevenly matched arms its species often exhibit. In New Zealand waters another genus. Allostichaster (Figs. 38-40) regularly reproduces by asexual transverse fission. In the tropics Linckia can regenerate the whole animal from a single arm. producing curious ‘ sea-comets ‘ in the process; in Cook Strait a species of Sclerasterias sometimes shows the same habit.
The brilliant colours of starfishes are due to biochromes which usually fade on preservation, and are chemically changed by alcohol. The colours include orange or vermilion (the two commonest), crimson (deep-sea forms), yellow, green, blue, violet, brown, as well as variegated patterns.
There are usually five arms, but many species have more than five, extreme cases occurring among the deep-sea Brisingidae, where as many as 44 long fragile arms may be present. Square starfishes with only four arms are abnormalities, but by no means rare. The largest starfishes (Linckia spp.) reach a metre in diameter; the biggest New Zealand species, Astrostole scabra (Fig. 41), is about half this size.
Starfishes are fast-growing animals and require a great deal of food. The carnivorous types will attack any animal which they can swallow whole, and will feed upon pieces of larger animals if the stomach can be applied to the food. Some species with suctorial tube-feet attack bivalve shellfish and sea-urchins. The valves of shellfish are forced apart by long-sustained suction exerted by the tube-feet and the arms; in this way members of the family Asteriidae do much damage to oyster fisheries.
Starfishes are not known to be dangerous to man, though tropical species occasionally cause septic wounds in the foot, as in the case of the Fijian genus Acanthaster, a coral-reef dweller with sharp spines. No New Zealand species is likely to cause injuries of any kind. Starfishes are not known to be poisonous to eat, though they are said to be bitter and unattractive. Of the few animals which do use them as food the walrus is perhaps most notable.
A number of parasites attack starfishes. A sea-snail, Stylifer, bores into their skin; a polychaete worm, Achloe, inhabits the ambulacral groove, a cirripede destroys the sex-gland of Coscinasterias and others, and in the tropics a slender fish, Fierasfer, inhabits the body cavity (apparently entering the mouth of its host, and boring through the stomach wall).
There are about 1,500 known species of starfishes, inhabiting the coasts of all known seas, but avoiding brackish and fresh water. Some live at low-tide level, or float on sea-weed at the surface of the sea (Calvasterias. Fig. 42); others burrow into the sea-floor. Twelve families are known to range into waters more than two miles deep, and one species (Porcellanaster caeruleus) has been recovered from the sea-bed at a depth of four miles. Next to holothurians, starfishes are the deepest-dwelling animals of the sea —page 130
probably because, like holothurians, they can extract nutriment from mud. Individual species usually have rather restricted bathymetric ranges, but where the continental slope is relatively steep, as it is off New Zealand, deep-water forms often ascend the slope, and shelf forms often tumble into deep water; thus the content of Cook Strait hauls is rather unpredictable.
From New Zealand waters 35 genera, embracing 46 species, are now known; six families have been added in the last few years, and one other family. the Porcellanasteridae. will probably be discovered here soon (it has been included in the key). It would now appear that there is a larger Indonesian and Australian element in the fauna than was formerly supposed, especially in the northern half of New Zealand. The supposed South American affinites seem to be negligible, and are perhaps a result of the epiplanktonic drift of seaweed-inhabiting forms, or the dispersal of planktonic larvae. Asterodon, a genus well represented in New Zealand waters, may have contributed a species to South America by way of the west-wind drift and Humboldt current. Certainly the main affinities of the New Zealand asteroid fauna are with the Indo-West-Pacfic, not with South America. A few deep-water species resemble North Atlantic forms; perhaps they are really cosmopolitan.
To use the key which follows, take each numbered paragraph consecutively. so long as the characters of the specimen in hand agree; if a character differs, go directly to the number shown in brackets. The key is complete to date, and is substantially systematic, so that the taxons occur in their accepted natural order. The length of the arm is given in the form of the major radius (R), measured from the centre of the disc to the tip of the arm, and is for an adult specimen. The colour in life is given, when known, and omitted if only preserved material has been described. The series of illustrations is representative, though not complete. In many cases it should be possible to make an approximate determination merely by inspection of the illustrations; the identification should then be checked against the key. Since many species undoubtedly remain to be discovered, a final determination can only be made against a complete description of each species. Unfortunately the literature is too scattered for citation here.
|1 (50)||Conspicuous marginal plates define the lateral contours of the body (Figs. 3-21). Upper surface of body covered by distinct plates, arranged in linear series and forming a strong pavement; they are either flattened like flagstones, or paxillate, i.e. bearing each a paxilla (Fig. 1). a cluster of spinules placed upon a projecting knob of a dermal plate.|
|2(19)||Tube-feet pointed with no sucking disc (Fig. 2A); upper surface usually covered by paxillae. Suborder PAXILLOSA. Three families may be expected to occur in New Zealand waters though only two of them are so far known.page 131|
|3 (4)||Vertical folds of skin (cribriform organs) occur between the marginal plates.|
|Abyssal genera, some of which may be expected from the Cook Strait canyon (none recorded to date).|
|4 (3)||No vertical folds of skin between any of the marginal plates.|
|5(16)||Marginal plates arranged in two similar series, an upper series (superomarginals) and a lower series (infermarginals)|
Five genera are so far known from New Zealand seas.
|6(13)||Madreporite naked and quite conspicuous.|
|7(10)||Oral area comprising only a few intermediate plates, and these do not extend far, if at all, into the ray; thus most of the adambulacral plates are in direct contact with the in'eromarginal series (Fig. 12)|
The genus ranges the warmer seas of the world, three species occuring in N.Z. All N.Z. species are 5-armed, and have tapering, pointed arms, with a flat upper surface and rather small central disc.
|8(9)||Each superomarginal from the base of the ray to its tip carries one prominent, erect spine, forming a kind of palisade all round the upper surface: Astropecten polyacanthus M. and T. Brownish, R. 90 mm., northern half of North Island, and warm Pacific generally, low tide to 100 fathoms. Common.|
|9(8)||Only the proximal superomarginals carry an erect spine (Astropecten dubiosus Mrtsn.), or none of them carry spines at all (A. primigenius Mrtsn.,). Both species are brownish and similar in size and general outline to A. polyacanthus. A. dubiosus ranges from N. Cape to Bay of Plenty, 40 to 120 fms., A. primigenius (Fig. 6) apparently ranges the whole N.Z. continental shelf and slope, from 30 to 300 fms., Bay of Plenty to Otago.|
|10(7)||Oral intermediate plates sufficiently numerous to extend most of the distance from the base of the arm to its tip, thus separating nearly all the marginal series from the adambulacral plates. (Fig. 13.)|
|11(12)||The central portion of each marginal plate is slightly elevated to form a flat table, separated on either side by a shallow fasciolar groove from the adjoining tables.|
The single N.Z. species, P. acuminatus Sladen (Fig. 13), resembles Astropecten in general appearance, but is bright salmon-pink; no superomarginal spines. R 65 mm., N.Z. off-shore waters and Southern Ocean. 20-950 fms.
|12(11)||No central table nor fasciolar grooves; instead each marginal plate is swollen into a tumid block,|
The single N.Z. species, P. neozelanicus Mrtsn. (Fig. 5), ranges the mud-banks off C. Campbell, Chatham Is., and Mernoo Bank, 50-150 fms.,page 132
|resembling a large Astropecten, R 140 mm., bright salmon-pink, both series of marginals carry spinules and larger, flattened adpressed spines.|
|13(6)||Madreporite obscured by a coat of paxillae.|
|14 (15)||Inferomarginals much broader than the superomarginals and, in consequence, project beyond them as a well-defined lower margin, visible from above (Fig. 3)|
A single N.Z. species, D. magnificus (Clark), disc flattened, outline stellate, the arms tapering rapidly to a blunt tip, marginals covered by a dense coat of spinules, without enlarged spines; R 160 mm., colour salmon-pink: 55-120 fms. Cook Strait and Gt. Australian Bight.
|15 (14)||Inferomarginals not projcting [sic] beyond the superomarginals.|
One species. P. knoxi Fell, from N.Z., having on each marginal plate a single enlarged spine surrounded by spinules, R 100 mm., orange-red. Cook Strait and Mernoo Bank, 60-500 fms. (A second species, possibly undescribed, has recently been found off Kaikoura.)
|16(5)||Superomarginals much smaller than inferomarginals and converted into paxillae, which thus form a distinct marginal row,|
Single genus, Luidia (Fig. 7), known from N.Z., having a small flat disc, and very long, flat, strap-like arms, which are deciduous and usually shed before preservation. The inferomarginals are broader than long and carry some large projecting spines. The two New Zealand species may be distinguished as follows:
|17 (18)||Inferomarginals bearing 2 or 3 erect spines. 5 arms, brown, not mottled. L. neozelanica Mrtsn. (Fig. 7), 35-150 fms., Hauraki to E. Marlborough.|
|18 (17)||Inferomarginals with 4 to 6 erect spines. 7 arms, mottled cream and black. L. varia Mrtsn., L. Barrier I. and C. Colville, 35 fms.|
A paxilla. Fig. 2: Tube-feet; A, pointed type; B, suctorial type. Fig. 3 : Dipsacaster magnificus, marginal plates; A, from above; B, in vertical section. Fig. 4: Pseudarchaster abernethyi. Fig. 5: Persephonaster neozelanicus. Fig. 6:Astropecten primigenius. Fig. 7: Luidia neozelanica. Fig. 8: Asterodon miliaris. Fig. 9: Asterodon robustus. Fig. 10: Asterodon dilatatus. Fig. 11: Eurygonias hylacanthus, lower surface. Fig. 12: Under surface of Astropecten, showing the relatively few intermediate plates, mainly confined to the base of the arm; Inf. inferomarginal; Ad., adambulacral; Fur., furrow; Ad.F.Sp., adambulacral furrow spines; Int., intermediate plate. Fig. 13: Under surface of Psilaster acuminatus, showing intermediate plates extending into proximal part of arm: lettering as in Fig. 12. Fig. 14:Asterodon robustus, the pairs of recurved glassy spines on the jaws. Fig. 15: Eurygonias hylacanthus, the unpaired recurved glassy spines of the jaws.
|19 (2)||Tube-feet with terminal sucking-disc (Fig. 2B).|
|20 (23)||Upper series of marginals (superomarginals) not placed directly over the corresponding inferomarginals, but alternate in position with them.|
|Suborder Notomyota. Deep-water forms.|
|21 (22)||An unpaired interradial marginal plate present in each series.|
One species, B. pentacanthus Fell, occurs in 400 fms. near Mayor I. It has an enormously enlarged erect spine on each of the 5 unpaired interradial marginal plates.
|22(21)||No unparied interradial plate in either series.|
A single New Zealand species, C. richardsoni Fell, Cook Strait. 400 fms., R 30 mm. A pectinate pedicellaria (Fig. 30) on each interradial area below.
|23 (20)||Superomarginals placed directly over the corresponding inferomarginals, not alternating. Suborder VALVATA|
|24(33)||On the lower surface of each jaw occur either 1 or 2 recurved, glassy spines, more or less imbedded in the surrounding spinulation.|
|Fam. Odontasteridae (Figs. 14 and 15)
This family is characteristic of southern seas, but is apparently lacking from Australia. The oldest known fossil member, Odontaster priscus Fell, occurs in the Jurassic of N.Z. Three genera are living in N.Z. waters at present, and may be distinguished as follows:
|25 (30)||2 recurved glassy spines on each jaw (Fig. 14).|
(including Diplodontias Fisher, which does not appear to warrant generic status) The three N.Z. species are separable as follows:
|26 (27)||About 30 marginals to the interbrachial are (arm-tip to arm-tip), outline stellate or stellate-pentagonal, upper surface of arms arched above the level of the superomarginals. A. miliaris (Gray) (Fig. 8). Cook Strait to Otago. 50 fms. Orange, vermilion, buff, or purple, R 50 mm.|
|27 (26)||About 20 marginals to the interbrachial are.|
|28 (29)||Marginals massive, without glassy warts; upper surface of arms flat; general outline stellate, the five arms tapering rapidly. A. robustus Fell (Fig. 9), Auckland Islands, littoral. R 67 mm., rich chocolate-red.|
|29 (28)||Marginals variable, the penultimate ones sometimes much enlarged so as to give the arm a spatulate outline; scattered glassy warts on the surface of the marginal plates. Orange-red. Littoral below 2 fms. Cook Strait to Snares Is. A. (Diplodontias) dilatatus (Perrier) (Fig. 10).|
|30 (25)||A single recurved glassy spine on each jaw (Fig. 15).|
|31 (32)||Marginals (especially inferomarginals) larger near the tips of the arms than at the interbrachial angles (Fig. 11). Large mushroom-shaped paxillae on the upper surface.|
The only known species, E. hylacanthus Farquhar, is restricted topage 135
|New Zealand, occurring off Oaro (Kaikoura) and off Wellington in a few fathoms. Brick-red, pentagonal to pentagonal-stellate, R 50 mm.|
|32 (31)||Marginals larger in the interbrachial angles than at the tips of the arms.|
A single N.Z. species, O. benhami (Mrtsn.) is a flattened pentagonal or pentagonal-stellate form ranging from Cook Strait to Otago, 40 to 300 fms. R 40 mm. Bright orange.
|33 (24)||Lower surface of jaw not carrying glassy recurved spines.|
|34 (35)||Disc very small, little more than a junction-point for the long, snake-like cylindrical arms (Fig. 16).|
A single N.Z. species, Ophidiaster kermadecensis Benham, having the plates of upper surface arranged in regular longitudinal rows, 5 arms, R 70 mm., Kermadec Is. and Bay of Plenty, below low tide to 30 fms.
|35 (34)||Disc large, arms flattened, not cylindrical, outline pentagonal or stellate.|
|36 (37)||Terminal marginal plates naked and enlarged, the other marginals covered over by granules. Large globular granules cover the upper surface (Fig. 17)|
A single N.Z. representative, Asterodiscus truncatus Coleman. Thick cushion-like pentagonal body, R 70 mm., yellow heavily blotched with vermilion, the granules purplish. 29-200 fms., Hauraki and Australian Bight.
|37(36)||erminal marginals not enlarged (though the penultimate marginals are often much enlarged in Pentagonaster, see Fig. 20) Fam. GONIASTERIDAE|
|38 (39)||Body covered by a membrane which obscures the outlines of the underlying plates and granules; inferomarginals projecting beyond the superomarginals and thus visible from above,|
The single N.Z. species. A. granulosus Fisher, is pentagonal-stellate with very attenuated arm-tips, R 135 mm., brick-red. 270 fms. Mayor I.; also Indonesia, same depth.
|39 (38)||No membrane obscures the outline of the plates, both marginal series similar.|
|40 (47)||Paxillae on the upper surface.|
|41 (42)||Paxillae of disc enlarged into hemispherical or polygonal knobs, covered with enlarged granules,|
A single N.Z. species, N. pedicelligera Mrtsn., pentagonal-stellate, arms with blunt tips, R 50 mm., reddish; littoral, Poverty Bay, rare (Fig. 18).
|42 (41)||Paxillae not specialised.page 136|
|43 (46)||An unpaired (but not recurved) median tooth on each jaw.|
The two N.Z. species may be distinguished as follows:
|44 (45)||Abyssal, granules only on the plates of the upper and lower surfaces and on the marginal plates. P. garricki Fell, stellate with tapering arms, R 80 mm., orange, Cook Strait, 550 fms.|
|45 (44)||Sublittoral, inferomarginals and plates of lower surface carry both granules and coarse spines. P. abernethyi Fell, stellate with tapering arms. R 110 mm., orange, Cook Strait, 55-63 fms. (Fig. 4).|
|46 (43)||No median unpaired tooth.|
The single N.Z. species, M. sladeni Benham, is orange, pentagonalstellate. with in the adult) inflated, tapering arms, R 120 mm. Cook Strait to Otago. 40-300 fins. Fig. 19).
|47 (40)||No paxillae on the upper surface, only spines; or else the plates are quite naked.|
|48 (49)||No spines on the marginal plates nor on the upper plates, which thus form a naked pavement, with linear rows of granules demarcating the plates (Fig. 20),|
with the single species, P. pulchellus Gray, an orange or vermilion pentagonal star ranging from Auckland to Otago in 2-120 fms. R 50 mm. The frequent enlargement of the penultimate marginals often gives the arms a clubbed appearance; usually there are only 4 pairs of marginals in the whole series, and the symmetrical arrangement of these gives the animal a remarkable aspect: said to be one of the most handsome starfishes of the world.
|49 (48)||Spines present on the marginal plates and on the plates of the upper and lower surface, though these are sparse and leave much of the plates naked (Fig. 21).|
One N.Z. species. H. trojana Fell, distinguished by having valvate
PLATE II— PHANEROZONIA (Figs. 16-21)and SPINULOSA (Figs. 22-29)
Fig. 16: Ophidiaster kermadencis. Fig. 17: Asterodiscus truncatus. Fig. 18: Nectria pedicelligera. Fig. 19: Mediaster sladeni; A, sexually mature form with inflated arm; B, immature form. Fig. 20: Pentagonaster pulchellus. Fig. 21: Hippasteria trojana. Fig. 22: Stegnaster inflatus. Fig. 23: Asterina regularis; A and B, pentagonal and stellate-pentagonal forms (Fig. 23A also represents the outline o!: Asterina aucklandensis). Fig. 24: Echinaster farquhari. Fig. 25: Henricia (small spp.). Fig. 26: Henricia ralphae. Fig. 27: Crossaster japonicus. Fig. 28: Pteraster bathami. showing osculum open. Fig. 29: Peribolaster lictor; A, one arm: B, tufts of spines of upper surface X 10. Fig. 30: Cheiraster richardsoni, pectinate pedicellaria of the oral interradius, X 10. Fig. 31: Cosmasterias dyscrita, unguiculate (or felipedal) pedicellaria, X 25.
|pedicellariae on the marginals as well as other plates. Deep brick red, R 105 mm. Pentagonal, off Chatham Is., 220 fms.|
|50 (1)||Marginal plates not conspicuous and not obviously defining the outline of the body (Figs. 22-43). Upper surface of the body not covered by a pavement of plates, but by rather inconspicuous reticulated or imbricated platelets, bearing spinules or spines.|
|51 (70)||Pedicellariae rare or absent, never conspicuous nor stalked.|
|Order Spinulosa (Figs. 22-29)|
|52(65)||Ambulacral grooves very narrow, much less than a quarter of the total width of the under-surface of the arm.|
|53(60)||Outline pentagonal or nearly so (Figs. 22-23)|
Two N.Z. genera.
|54 (55)||Ambulacral groove bordered on either side by a palisade of uniform furrow spines, held together by a longitudinal radial web. Body very thin and domed so that the lower surface is concave (Fig. 22)|
A single N.Z. species, S. inflatus (Hutton), R 50 mm., greenish-grey above, cream below, or irregularly mottled, rock-pools. North I.
|55 (54)||Ambulacral groove bordered on either side by a series of tufts or fans of spines, not held together in a continuous web. Body usually somewhat arched above and flattened below.|
|Genus Asterina (Fig. 23)
The species of this genus occurring in N.Z. are at present separated on characters of the adambulacral spine-armature, as follows:
|56 (57)||Each adambulacral plate carries one spine on its outer side, and three spines on the furrow side. A. regularis Verrill. R 30 mm., colour variable, low tide to 15 fms. Throughout N.Z. (In Cook Strait much variation occurs in the adambulacral armature, suggestive of hybridisation with the following species, but this remains hypothetical).|
|57 (56)||Each adambulacral plate carries 3 or more outer spines as well as 3 or more inner (furrow) spines.|
|58 (59)||Three outer adambulacral spines and three furrow spines united in a fan by a web. A. novaezelandiae Perrier. Not seen since the holotype was described in 1875, and validity doubtful. It may be a variant of A. regularis, or alternatively may be almost swamped in an introgressive hybridisation with that species.|
|59 (58)||Numerous outer adambulacral spines, and 5 or 6 furrow spines. Red or claret-coloured, R 30 mm. Low tide, Auckland I. to Banks Peninsula, A. aucklandensis Koehler.|
|60 (53)||Disc small with 5 subcylindrical tapering arms (Figs. 24-26). Colour nearly always a very brilliant orange-vermilion.|
Two N.Z. genera, distinguished as follows:page 139
|61 (62)||Plates of upper surface bearing simple, stumpy, isolated blunt spines (Fig. 24).|
with a single N.Z. species, E. farquhari Benham, R 120 mm., Cook Strait to Otago, 40-290 fms.
|62 (61)||Plates of upper surface bearing small, delicate spinelets, usually in groups, and not fixed immovably to the plate, but held in place by a membranous connection, or supported in thick tufts.|
|63 (64)||Rays exceeding 50 mm. in length, spinules of the upper surface sparsely scattered in groups of 2-3 or singly (Fig. 26). H. ralphae Fell. 40 fms., off east Otago.|
|64 (63)||Rays less than 50 mm. (A group of species (Fig. 25) whose systematic arrangement requires revision; it would appear from information recently supplied by Miss A. M. Clark of the British Museum that more than one species has been confused under the name H. compacta, which properly belongs to a juvenile individual from Challenger Station 166, 275 fms. off C. Farewell.)|
|65 (52)||Ambulacral grooves quite open, at least one quarter of the total width of the lower side of the arm.|
|66(67)||Arms numerous (9-11), arranged around a large central disc (Fig. 27).|
|Fam. Solasteridae, the sun-stars|
A single N.Z. species, Crossaster japonicus (Fisher), R 85 mm., marbled pink and white or uniform pink, Cook Strait and Chatham Is., 50-320 fms.
|67 (66)||Arms normally 5, outline of body pentagonal to stellate.|
|68 (69)||Upper surface roofed by a membrane enclosing a dorsal brood-chamber and having a conspicuous central opening (osculum), (Fig. 28).|
A single N.Z. species, Pteraster bathami Fell, pentagonal cushion-like body, uniform deep cream colour, R 50 mm., 300 fms., off Otago.
|69 (68)||No dorsal brood-chamber nor osculum; on the upper surface the plates carry tufts of slender spines, enclosed in groups of 3-4 in membranous sheaths, each tuft thus rather resembling a closed umbrella.|
with a single N.Z. species. P. lictor Fell, cream coloured, pentagonalstellate with truncated arms, R 30 mm., 130 fms., off Chatham Is. (Fig. 29).
|70(51)||Pedicellariae numerous, conspicuous, including stalked types (Fig. 43).|
Three families are known from N.Z.
|71(72, 73)||Deep-water forms with a small, central, circular disc very distinctlypage 140|
|set off from the ring of slender arms which arise from it; arms usually numerous and deciduous, seldom obtained intact,|
A single N.Z. species, Brisingenes delli Fell, 14 arms about 200 mm. long, disc about 25 mm. in diameter, off Mayor I. in 270 fms. (Fig. 33).
|72(71)||Deep-water forms with a small disc which is not distinctly set off from the five long tapering arms. Only straight pedicellariae present.|
A single N.Z. representative. Zoroaster spinulosus Fisher, R 160 mm., pink, 220-280 fms., off Chatham Is. (Fig. 36).
|73(71)||Disc not distinctly demarcated from arms, crossed pedicellariae always present|
Seven N.Z. genera.
|74 (79)||Upper surface armed with rather conspicuous spines which give the animal a distinctly prickly aspect, especially in dried specimens (Figs. 32, 37, 41).|
|75 (78)||Adambulacral plates each carry 2 spines.|
|76 (77)||5 arms, each of which is more or less pentagonal in cross-section; a longitudinal web links all the outermost inferomarginal spines along the arm.|
with a single N.Z. representative, S. mollis (Hutton). Disc small, arms easily detached, orange and buff tints predominate. R 100 mm. 40-300 fms., Cook Strait to Otago (Fig. 32).
|77 (76)||7 to 9 arms. No inferomarginal web, arm rounded in section,|
with single N.Z. species A. scabra (Hutton), the common 7-armed starfish (individuals with 8 or 9 arms are not unusual) reaching R 250 mm., the largest N.Z. starfish, littoral, throughout N.Z. (Fig. 41).
|78 (75)||Adambulacral plates each carry only I spine. Fissiparous, newly divided|
PLATE III— FORCIPULATA
Fig. 32: Sclerasterias mollis. Fig. 33: Brisingenes delli. Fig. 34: Stichaster australis. Fig. 35 Cosmasterias dyscrita. Fig. 36: Zoroaster spinulosus. Fig. 37: Coscinasterias calamaria. Fig. 38: Allostichaster polyplax. Figs. 39, 40: Allostichaster insignis. two growth-stages after transverse fission. Fig. 41: Astrostole scabra. Fig. 42: Calvasterias suteri, lower surface of female, during breeding Period, showing cluster of young over mouth. Fig. 43: Forcipulate pedicellariae; straight type on left. X 5: crossed type on right, X 20.
|individuals commonly found with regenerating arms. 7 or more arms,|
with one N.Z. species, the widespread Indo-Pacific form, C. calamaria (Gray). Normally with 11 arms, but variants common. Greenish-grey and bluish-grey, tube-feet orange, R 180 mm., littoral, down to 20 fms. N. Cape to Stewart I. (Fig. 37).
|79 (74)||Upper surface armed with only rather inconspicuous spinules or with rounded granules or almost naked.|
|80 (87)||Adambulacral plates each carry 2 spines.|
|81 (82)||5 arms, mouth deeply sunken into the disc, unguiculate pedicellariae occur, i.e. 2-valved pedicellariae in which each valve resembles a clawed hand (Fig. 31)|
with one N.Z. species, C. dyscrita Clark, R 70 mm., 130-200 fms. Chatham Is. and off Victoria, Australia (Fig. 35).
|82 (81)||6 to 13 arms, mouth at same level as ambulacral grooves, no unguiculate pedicellariae.|
|83 (84)||10 to 12 arms (exceptionally 9 or 13), all of uniform size, single madreporite. not fissiparous.|
with one N.Z. species, S. australis (Verrill), buff or mauve or brown, clinging to rocks in rough surf or in deeper water down to 300 fms. occasionally), N. Cape to Bluff. Body covered above by hemispherical granules like pinheads (Fig. 34), R 120 mm.
|84 (83)||6 to 8 arms, rarely 5; normally 2 or 3 madreporites. fissiparous, the arms commonly occurring in 2 sets of differing size.|
The two N.Z. species are thus distinguished:
|85 (86)||6 arms (often 3 larger and 3 smaller), A. insignis (Farquhar), R 35 mm., bluish-grey, Cook Strait to Auckland and Campbell Is. (Figs. 39-40).|
|86 (85)||8 arms, (often 4 larger and 4 smaller), A. polyplax (M. and T.), R 70 mm. bluish-grey, or buff, littoral, N.Z. south to Stewart I., also southern Australia and Tasmania (Fig. 38).|
|87 (80)||Adambulacral plates each carry only I spine. 5 short, thick arms.|
Two species in N.Z. as follows:
|88 (89)||Skin almost naked, save for a few scattered granules or spinules, sometimes arranged monoserially along the mid-line of the arm above. C. laevigata (Hutton). Grey, green or brown, R 77 mm., brood-protecting, the young adhering in a cluster over the mouth (as in Fig. 42). Auckland I., Campbell I. and Antipodes I., unknown from N.Z. mainland.|
|89 (88)||Well-marked median series of spinelets along each arm. in short transverse arcs or clusters of 3-4, C, suteri (de Loriol), fawn or grey-green with lighter spinules. Brood-protecting. Banks Peninsula to Snares, Auckland I. and Campbell I. (Fig. 42).|