The marine fauna of New Zealand: Basket-stars and snake-stars (Echinodermata: Ophiuroidea: Euryalinida)

82 Pages·2000·16 MB·English

by  Mcknight, D G

ISSN 1174–0043; 115 (Print)
ISSN 2463-638X; 115 (Online)
Cover photo: Asteroporpa a11straliensis H.L. Clark, on a plexaurid gorgonian,
Three Kings Islands. Photo: Roger V. Grace.
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/
NATIONIANLS TITOUFT E
WATEARN DA TMOSPHERREISCE AR(CNHI WA)
TheM ariFnaeu noafN ewZ ealand:
Basketa-nsSdtn aarkse -stars
(EchinodOeprhmiautraoE:iu dreyaa:l inida)
D.GM.c Knight
National oIfWn astteairnt dAu ttmeo spheric Research
(NIWA)
P.OB.o x1 4-90K1i,l biWrenlilei,n gton
NEWZ EALAND
NIWBAi odivMeermsoi1it1ry5
2000
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/
Cataloguing in Publication
McKNIGDH.TG,.
Thmea rifnaeuo nfNa e wZ ealaBnads:k eta-nSsdnt aakres(- Escthairnso dermata:
OphiurEouirdyeaal:/i b nyi dDaoG)n. Ma clKdn i-gWhetl linNgItWoA(n N:a tional
InstoifWt auttaeenr Ad t mospRheesreiac2r 0c0h0) ,
(NIWBAi odiversiItSyS0 N0m 8e3m-o17i19r50,)3 :
ISB0N- 478-23215-2
I. TitleI I.S eries
UDC
SerEideist oDre nnPi.Gs o rdon
Typebsye t Rose-MCa.Tr hioem pson
NatiIonnsatloi fWt auttaeenr Ad t mospRheesreia(crN cIhW A)
(incorpNo.rZOa.ct eianngo gIrnaspthiitcu te)
Wellington
Receifvoperud b lic-aAtuigou1ns9 t9 8
©NIWAC opyr2i0g0h0t
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/
CONTENTS
Page
ABSTRACT 5
INTRODUCTION 6
CHECKLIST OF SPECIES 8
LIST OF ST AT ONS 9
SYSTEMATICS
Family ASTERONYCHIDAE 13
Family ASTEROCHEMAT IDAE 15
Family EURY ALIDAE 42
Family GORGONOCEPHALIDAE 45
DISCUSSION 72
ACKNOWLEDGMENTS 75
REFERENCES 75
INDEX 78
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/
Frontispiece: Astrobrachion constrictum (Farquhar): two colour morphs on the black coral
Antipathes fiordensis, Port Pegasus, Stewart Island. Photo: Roger V. Grace.
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/
TheM ariFnaeu noafN ewZ ealand:
Basket-asntdSa nrask e-stars
(EchinodeOrpmhaituar:oE iudreyaa:l inida)
D.GM.c KNIGHT
National Institute of Water and Atmospheric Research
(NIWA)
P.O. Box 14-901, Kilbirnie, Wellington
NEW ZEALAND
ABSTRACT
The euryalinid fauna of the New Zealand region is now known to comprise some 33 species in 15 genera,
with all families of the order represented. This review is based on collections held by the National Institute
of Water and Atmospheric Research (NIWA) and the Museum of New Zealand (NMNZ), comprising
over 1650 specimens. Four new species are added to the fauna (in the genera Asteroschema, Ophiocreas,
and new genus Astroniwa), and two new records (Astrotoma dr�chi and Astrodia tenuispina).
Four species are restricted to the continental shelf (< 200 m) and a further seven occur on the
continental slope. Most of the species (16) occur on the slope between 200 m and 2000 m. Only three
species are known from depths below 2000 m.
Seven species are known from the far north of the region, while nine extend further south; two
species are known only from the central New Zealand area, three are more southern in distribution, and
eight are more or less widespread.
Nine species are endemic to the region. Five species form a distinct element, present elsewhere only in
Australian seas; 12 species form a relatively widespread lndo-West Pacific element; one is more or less
circumpolar in temperate waters, and three species are geographically widespread.
Keywords: Echinodermata, Ophiuroidea, Euryalinida, classification, distribution, new species,
new genus, marine fauna, New Zealand.
5
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/
INTRODUCTION
Brittle-stars (Phylum Echinodermata, Class Ophiu­ The arms are of solid construction, with an internal
roidea) are relatively common members of marine row of vertebrae, each composed of two fused
faunas, occurring from the intertidal zone to deep­ ambulacral ossicles. In contrast to the Asteroidea,
sea trenches. They generally have a more or less ambulacral grooves are absent and the podia are
circular disc, usually with five, but sometimes up to reduced to small papillate organs which lack an
eight, arms. When captured the arms are often shed ampulla. All species lack an intestine and anus, and
and become fragmented. In most species the arms do all but one genus lack extensions of the digestive
not branch, although a few have the arms repeatedly system into the arms. The gonads are restricted to the
branching. disc in most genera, and usually open ventrally at the
The first New Zealand ophiuroid was described sides of the arms bases. The Ophiuroidea are
(Ophiopsn11111111s 11inrnlntn
in 1869 (Verrill)), and commonly known as brittle-stars, due to the brittle
Mortensen (1921) summarised the history of the nature of the arms, or as snake-stars from the snake­
fauna. Of the 16 currently recognised families, all but like appearance of the arms. Ophiuroids are common
one, Ophiocanopidae are represented locally. The members of marine fauna! assemblages, although are
present report details members .of the order sometimes overlooked because of their generally
Euryalinida from the New Zealand region, defined small size and cryptic habits.
by the boundaries 24° S to 57°30' S latitude, 157° E to Most ophiuroids lack the varied external appear­
°
167 W longitude (CANZ 1997). ance so evident in the Asteroidea. Most have a small
Members of this order have the arms coiling flattened disc, rounded, pentagonal, or scalloped in
vertically. They commonly lack distinct plates or outline, from which depend the five or more long
scales on the upper disc surface, the radial shields are slender, smooth or spiny arms.
usually elongate, bar-like, or sometimes composite; The order Euryalinida is characterised by the
skin or granules cover the upper and lower disc presence of a skin covering the disc, below which there
surfaces, and may extend along the arms. The arm­ are generally no regularly arranged large plates; the
spines are often transformed into hooklets, especially arms usually roll into vertical coils and the arm­
near the arm-tips. It is in this order that branching spines are placed at the ventrolateral margin of the
arms are present. arms and point downwards. This order contains all
The first euryalinids described from the New the genera with branching arms.
Asterosc/1e111n
Zealand region were two species of Five elongate pairs of areas are generally visible
(Lyman 1879, 1882). Two further euryalinids were above the dorsal disc surface (aboral) in the
added in the 1900s (Farquhar 1900; Benham 1909), Euryalinida.' These are the radial shields, and may be
and a further five species were recorded, with a entire or composed of several "soldered" ossicles. The
comprehensive account of the known fauna, by radial shields may be skin-covered or variously
Mortensen (1924). In later years, the species list slowly ornamented with granules, tubercles, or short spikes;
increased until Baker (1980) presented a major granules may be flattened or domed, in which case
revision of the euryalinid fauna of the Southwest they may be regarded as small tubercles. Their surface
Pacific, describing 26 species from the New Zealand is smooth, nodular, or beset with fine spines or thorns.
region, including six new species and one new genus. The rest of the disc surface may also be variously
The present report summarises further collecting in covered with ornamentation, occasionally plated, or
the New Zealand region and adds seven more species, simply covered over by naked skin. Stronger marginal
including four new species and one new genus. plates may be evident at the disc margin. The mouth
lies on the ventral or oral surface.
The entire ventral surface may be naked or orna­
General Features
mented as the dorsal surface, or the ornamentation
may be restricted to the area close to the mouth
The class Ophiuroidea comprises generally stellate opening, the oral frame. Within the oral frame there
echinoderms with slender arms, usually simple but are usually five plates; from the outer edge these are :
branching in a few genera. There are commonly five the oral shield, an unpaired rounded to elongate single
arms but in a few species seven or eight may occur. plate, lying in the mid-interradius; flanking the oral
6
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/
stueld or situated orally to it is a pair of ad oral shjelds, families Gorgonocephalidae and Euryalidae. There
mside of which are two oral plates Uaw plates, half are arms from the oral frame in both families,
five
a",·s). These latter extend into the mouth field and but these divide near the disc margin or beyond; the
almost always bear papillae along their sides (oral branching can be equal or often unequal, with one
papillae) and, at the tip, tooth or dental papillae. branch longer than the other, or with more sub­
Below the tip of the jaw is a vertical row of pointed divisions.
or nattened calcareous teeth. In addition, situated The family Gorgonocephalidae also differs from
below the oral papillae are the first two podia, the oral others in that the arms have transverse bands of small
tentacles or podia, arising from their respective oral hooks, each with a terminal tooth and sometimes with
tentacle-pores. Usually one of the oral shields is modi­ subsidiary teeth below. These girdle bands of girdle
fled as a madreporite, although it may be scarcely booklets are arranged one or two to each arm segment,
" tinguished; in some species there may be more than and more or less alternating with bands of granules.
cne such madreporite; also the madreporite may be
�laced at the outer edge of the oral frame or enclosed
ithin it. Habitat
Outside the oral frame the ventral interradial areas
.:iay be naked or have a sparse to complete cover of Within the New Zealand region most five-armed
granules or tubercles. Alongside the ventral surface species of the Euryalinida occur as epizooites on
o' the arm is an elongate opening, the genital slit, sponges, antipatharians, pennatulacea, gorgonians,
hereby the gonads communicate with the exterior, and alcyonaceans and occasionally may be found on
�d which also appear to assist in respiration. This submerged logs or rocks. They are generally com­
enital slit is margined on each side by the genital moner beyond the continental shelf, although one
nlate, although that part adjacent to the arm may be species is relatively common on antipatharians in
�den by skin or ornamentation. Fiordland. In contrast, most specimens with branch­
As noted above, the arms are internally composed ing arms have been taken on level bottoms, often
f united ambulacral ossicles, and for each arm seg­ where the sediment is fine-grained. All species are
ment so formed is a pair of podia (sometimes sheathed thought to feed mainly on small planktonic orga­
by skionn )ei ther side of the ventral surface; close by nisms, for which the hooked distal arm-spines and
the podia are the downwardly directed arm-spines. girdle hooklets are obvious capture devices;
In the Euryalinida these never extend up the sides of apparently those species with branching arms have
arms. Arm-spines are usually absent from the first one difficulty climbing or clinging to coelenterates and
or hvo arm segments; at first they are short, but from other benthic epifauna.
beyond the disc are longer, and those of each segment
may differ in length; commonly they are beset with
small spines, thorns, or prickles, especially near the Order Euryalinida
bp, and they may be enveloped in a glandular bag of
skin. Near the arm-tip the arm-spines usually become Ophiuroids with disc and arms covered by skin, with
distally hooked, where they may have additional or without granules; arms coil vertically and vertebrae
teeth below. Covering over the arm surface there may articulating by broad hourglass-shaped surfaces.
be thin calcareous plates, often irregular in outline, Arms usually five at base, but may branch beyond
although more definite in some. These plates may base, a few species with more than five arms. Arm­
extend down the sides of arms, and arm-spines spines point downwards.
generally arise from lateral arm-plates at the ventro­ Four families are currently recognised and all are
lateral margin. The arm ventral surface may be present locally.
irregularly paved with flat plates or there may be Species with unbranched arms are commonly found
regular ventral arm-plates present, either separating clinging to cnidarians and are often conspicuous
the lateral arm-plates or situated distal to them, where because of colour or shape. Those with branching
they meet on the ventral midline. arms are commoner on softer seafloor sediments, and
Species with branching arms are restricted to the some are very large and conspicuous.
7
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/
CHECKLIST OF SPECIES
(* new species and records described in this Memoir)
Family ASTERONYCHIDAE Family EURYALIDAE
Astero11yx love11i Muller & Troschel Astrocerns elegn11s (Bell)
*Astrodin te1111ispi11n (Verrill) Astrocerns ken11ndecensis Baker
Family ASTEROSCHEMATIDAE Family GORGONOCEPHALIDAE
*Astcrosc/1e111n bidwillne n.sp. Asteroporpn n11strnlie11sis H.L. Clark
Asterosc/1e111n l10rrid11111 Lyman Astcroporpn rctic11/ntn Baker
Asterosc/1c111n igloo Baker Astrobon grn1111lnt11s (H.L. Clark)
Asterosc/1e111n 111igrntor Koehler Astrobon sp.
Asterosc/1e111n snlix Lyman Astroclnd11s to11gmws Doderlein
Asterosc/1e111n t11b1feru111 Matsumoto Astrode11dru111 eli11gn111itn Baker
*Asterosc/1e11in wrigliti n.sp. *Astro11iwn 1wk11rn11gi n. gen. et sp.
Astrobrncliio11 ndltnere11s (Studer) Astrotl10rnx wnitei (Benham)
Astrobrnc/1io11 co11strict11111 (Farquhar) Astrotl1ro111b11s rugos11s H.L. Clark
Opltiocrens jnpo11iws Koehler Astrotltro111b11s vecors (Koehler)
*Opltiocrens 111orte11se11i Koehler *Astroto111n drncl1i Guille
Opltiocrens ocdip11s Lyman Gorgo11ocephn/11s chilwsis (Philippi)
Opl1iocrens sibogne Koehler Gorgo11occplwl11s dolic/1odncty/11s Doderlein
Opltiocrens willsi n.sp. Gorgo11oceplwl11s p11st11/nt11111 H.L. Clark
Gorgo11oceplinl11s s1111dn1111s Doderlein
Tabular Key to Families of the Order Euryalinida
1 2 3 4 5 6 7
Asteronychidae no no no no no no 5
Asteroschema tidae no yes no no no no 3-8
Euryalidae no yes yes yes yes yes 3-9
Gorgonocepha Ii dae yes no no 110 yes no 5
1 Hooklets on dorsal sides of arms
2 Gonads enter arms
3 Vertebrae with ventral furrow closed
4 Distal arm-spines with a serially perforated lamina
5 Arms may branch
6 Distal arm-joints long and slender
7 No. of primary arms
8
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/