The North Otago Shelf Fauna. Part II—Echinodermata

Transactions of the Royal Society of New Zealand : Zoology, Volume 2, Issue 23, 31 October 1962, Page 199

The North Otago Shelf Fauna. Part II —Echinodermata

John Graham Oamaru

By

[.Received by Editor, April 26, 1962.]

Abstract

A checklist of 30 species of echinoderms, collected during 1958-61 from the North Otago shelf, is presented. The abundance of each species in relation to described sea-bed biotope is recorded and some distributional and other local variations are discussed.

Introduction

The checklist has been compiled from identified species collected inter.tidally and by commercial fishing trawl as described by the author in an earlier paper (Graham, 1962). The listed species have been identified by specialists and subsequent material compared with these types.

The commercial fishing trawl used, with a 20 m ground-rope which sweeps the sea-floor, is an admirable medium for the collection of Asteroidea, Ophiuroidea and some genera of the Echinoidea. It is noteworthy that very few echinoderms are damaged even when taken in large trawls of fish and/or bottom debris.

The North Otago shelf has been divided into four zones. These have been described previously and are, briefly, as follows: Zone 1, tidal rocks and beaches; Zone 2, 9t055 mof depth, gravel and muddy shell-sand; Zone 3,55 mtoßß m, muddy shell-sand with a heavy over-growth of a weed-like polychaete worm; Zone 4, clean bottom of muddy shell-sand out to 120 m—the limit of trawling operations.

CHECKLIST OF ECHINODERMATA FROM THE NORTH OTAGO SHELF

Abbreviations. 1, Zone 1; 2, Zone 2; 3, Zone 3; 4, Zone 4; G, common; U, uncommon; R, rare; b, cast on beaches; F, initially identified by Professor H. B. Fell; DP, initially identified by D. L. Pawson, M.Sc.; HC, initially identified by Miss H. E. Clark, M.Sc.

ASTEROIDEA

Astropectinidae Persephonaster neozelanicus Mrtsn. 3U, 4U, F Odontasteridae Asterodon miliaris (Gray) 2U, 3G, 4C, F A. dilatatus (Perrier) IRb (3 only), F. Odontaster benhami (Mrtsn.) 4G (small area), F.

Goniasteridae Mediaster sladeni Benham 4U, HG. Pentagonaster pulchellus Gray lUb, 2U, 3G, 4G, F. Asterinidae Patiriella regularis Verrill IG, 2G, 4R (1 only), F.

Echxnasteridae Henricia ralphae Fell 4G (small area), F. Asteriidae Sclerasterias mollis (Hutton) 2G, 3C, 4C, F. Astrostole scahra (Hutton) 2R, F. Coscinasterias calamaria (Gray) lU, 2G,

F. Stichaster australis (Verrill) 1R (2 only), F. Allostichaster insignis (Farquhar) IR, 2U, 3U, 4R, F. A. polyplax (M & T) IC, 2R (2 in kelp hold-fast), F.

OPHIUROIDEA

Ophiomyxidae Ophiomyxa brevirima H. L. Clark 2U, 3U, 4U, F. Amphiuridae Amphiura magellanica Ljungman 2R, F. Ophiocomidae Ophiopteris antipodum E. A. Smith 3R, F. Ophiocoma bollonsi Farquhar 3U, 4R, F.

Ophioghitonidae Ophionereis fas data (Hutton) IU, 2U, 3R, 4R, F. Ophiodermatidae Pectinura maculata (Verrill) 2G, 3U, 4R, F. P. gracilis Mrtsn. 2U, 3U, 4U, F.

EGHINOIDEA

T EMNOPLEURIDAE Pseudechinus huttoni Benham 2G, 3C, 4U, F. P. albocinctus (Hutton) 2G, 3U, F. P. novae-zelandiae (Mrtsn.) 2U 3 3U, F. -Echinometridae Evechinus chloroticus (Valenciennes) 1U 3 2G, F.

( E. chloroticus var. paucituberculatus) 2R, F. Echinobrissidae Apatopygus recens (M. Edwards) 2R (1 only), F. Spatangidae Echinocardium datum (Pennant) 3R (1 only), F.

HOLOTHUROIDEA

Stighopodidae Stichopus mollis (Hutton) 2C, 3C, 4C, DP.

Phyllophoridae Amphicyclus thomsoni (Hutton) 2U, 3U, DP. Neothyonidium dearmatum (Denby & Kindle) 2R, 3R, DP.

CRINOIDEA This Class is not represented.

Discussion The colour range of the listed species conforms to the published accounts. 'With the exceptions of Patiriella regularis, a large healthy specimen of which was trawled in 100 m (February, 1961), Odontaster benhami and Henricia ralphae which are not recorded here shallower than 90 m and Ophionereis fasciata taken in 100 m, there are no appreciable deviations from hitherto recorded depth habitats. (Fell, 1948-52-58-59) The species of Odontaster and Henricia referred to above .are found only in a limited area at the southern end of Zone 4 between 90 and 100 m.

As no Persephonaster neozelanicus larger than 14 centimetres diameter has been taken, it is suggested that this species here is a geographical variant or a juvenile form in a nursery habitat. Several specimens examined proved to have, within the stomach walls and apparently in the course of digestion, a selection of tiny molluscs. These were Nucula hartvigiana, Notocallista multistriata, Stiracolpus symmetricus, Tanea zelandica and Austrofusus glans (H. E. Clark, personal communication, 28/6/61). Six specimens have been noted in this state. Sclerasterias mollis in the shallower depth of Zone 2 is represented by adult and/or senile forms.

As the small species, Amphiura magellanica, was taken only from the holdfast of the kelp, Macrocystis sp., it is evident that it may be more plentiful than recorded as the kelp-bed areas cannot be trawled.

Only one specimen of Echinocardium cor datum is here noted (three were taken off North Otago by the Government Trawling Expedition of 1907 from their Station 30). The author has trawled many times over this area and it must be doubted whether this species “be fairly abundant” as suggested (Benham, 1909). However, the disadvantages of the commercial fishing trawl as a medium for taking specimens of the infauna are also admitted.

It is interesting to note that a specimen of what appears to be a hybrid between Pseudechinus huttoni and P. albocinctus was taken from Zone 2 and is in the possession of the author. Such hybridism (if the interpretation is correct) has not hitherto been recorded.

With the exception of a few tests of Pseudechinus huttoni , all echinoderms taken at sea have been living specimens. Holothurians, other than Stichopus mollis, are but rarely found in mud swept up by the trawl and, as yet, no crinoids have been taken.

Species of the Order Forcipulata, the arms of which have a tendency to break from the central disc, can be “ fixed ” effectively, at sea, by immediate immersion in 5 % formalin. With care, however, all echinoderms are easy subjects for preservation.

Acknowledgments

Professor H. B. Fell, Victoria University, has identified 26 of the listed species, given copies of relevant publications and generally advised and encouraged me. I acknowledge, gratefully, his valuable assistance and the generous allowance of his time. I thank Mr D. L. Pawson, Victoria University, for identifying the holothurians and for his information on colour, depth range, and the correct preservation. I thank, also. Miss H. E. Clark, Victoria University, for her identification of Mediaster sladeni and for the dissection of the specimens of Persephonaster neozelanicus. Master Brian Innes, of Oamaru, is congratulated and thanked for spending 90 minutes prising the first specimen of Stichaster australis from the rocks and presenting it to me.

References

Benham, W. 8., 1909. Scientific Results of the N.Z. Government Trawling Expedition, 1907. Rec. Canterbury Mus. Vol. 1, No. 2, p. 110.

Fell, H. 8., 1948. A Key to the Sea Urchins of New Zealand. Tuatara, Vol. 1, No. 3, pp. 6-13.

1952. Echinoderms from Southern New Zealand. Zool. Pubns. Viet. Univ. Coll. 18.

lington. 24.

Graham, J., 1962. The North Otago Shelf Fauna, Part 1, Mollusca. Trans. Roy. Soc. N.Z. Vol. 2, No. 9, pp. 53-50.

John Graham, Maude Street, Oamaru.

CORRIGENDUM In my paper on the North Otago Shelf Fauna, Part I, No. 9, of this volume of the Royal Society Transactions, Zoology, p. 57, line 9: Maurea pellucida pellucida should read Maurea pellucida forsteriana.