Oligocene Echinoids from Trelissic Basin, New Zealand

Transactions of the Royal Society of New Zealand : Zoology, Volume 4, Issue 15, 17 April 1964, Page 201

Oligocene Echinoids from Trelissic Basin, New Zealand

H. Barraclough Fell

By

[Received by the Editor, August 14, 1963.]

Abstract

A small collection of early to middle Oligocene echinoids includes a new genus and new species of Temnopleuridae, and a new species of Brissopsis closely allied to the extant Indo-West-Pacific B. luzonica. The occurrence of Brissopsis in New Zealand so early as the Oligocene is significant, for the genus (though otherwise widely distributed) is unknown from South America and Antarctica; the Oligocene species is evidently an early member of the typical Kleinia assemblage, still surviving in the Indo-West-Pacific, and already known to have been present in Java in the Miocene. The ecology of Brissopsis forbids dispersal by epiplanktonic drift, and probably demands a benthal dispersal route. Such route must therefore have been lacking between New Zealand and South America (and Antarctica) since the Oligocene. The other Oligocene genera also point to Indo-West-Pacific derivation and contraindicate southern connexions of the New Zealand plateau.

The following brief report on fossil echinoids from the Trelissic Basin, Canterbury, New Zealand, is intended merely to establish their nomenclature and to facilitate their citation in other contexts. The co-operation of the New Zealand Geological Survey, and in particular of Dr C. A. Fleming, is gladly acknowledged. I am grateful to Mr M. D. King, Victoria University of Wellington, for the photographs which illustrate the type specimens. The zoogeographic implications of the faunule are consistent with inferences previously drawn from study of Tertiary and Recent echinoderms of New Zealand and adjacent regions.

Order TEMNOPLEUROIDA Family Temnopleuridae Goniosigma n. g. A temnopleurid resembling Grammechinus, but differing in having the small secondary tubercles of the interradial (admedian) angles of the interamb plates arranged in vertical zig-zag series, parallel to the abradial sutures, so as to form sigmoid patterns on either side of the interradius. The generic name is of neuter gender.

Type Species. Echinus enysi Hutton, 1873. Goniosigma enysi (Hutton) (Plate 1, figs. 1,2). Echinus enysi Hutton, F. W. Catalogue of the Tertiary Mollusca and Echinodermata of New Zealand, 1873, p. 39. Diagnosis. As for the genus, only the type species being known.

Hutton’s brief description matches the type, though the species would have been quite unrecognisable but for the preservation of the holotype in the collection of the N.Z. Geological Survey. The characteristic temnopleurid sculpture and non-crenulate imperforate tubercles are not mentioned by Hutton, nor the sigmoidal pattern of the secondary tubercles, the distinctive feature of the genus; no figure was given. Hutton’s name may, nonetheless, be retained on the basis of the labelled holotype specimen.

The genus Grammechinus Duncan and Sladen was recorded from New Zealand by Hawkins (1925) on the basis of Echinus enysi, and this determination was accepted by Fell (1953). However, a review of the temnopleurid genera since carried out suggests that E. enysi should not be referred to Grammechinus, for the differences from the type of that Indian Miocene genus (indicated in the diagnosis of Goniosigma) are of the order now regarded as generic rather than specific. Other differences of lesser value are the presence on each ambital amb plate of one primary and one secondary tubercle (as opposed to three similar tubercules in Grammechinus ), and the lack of horizontal sunken sutural depressions in Goniosigma. The two genera are doubtless related, and both share the unusually broad interambulacral plates, bearing a horizontal series of enlarged secondary tubercles, with a slightly larger primary placed midway along the series. Goniosigma, though restricted to New Zealand, should probably be considered as an Indo-West-Pacific element therefore.

Holotype. Registration No. EC272, in the collection of the New Zealand Geological Survey. Horizontal diameter 28 mm, height approximately 16 mm. Apical region lost. Peristome obscured, but evidently small, approximately 8 mm diameter. Locality. “ Broken River (L) ”, Trelissic Basin, Canterbury. Horizon. Whaingaroan-Duntroonian (Lower-Middle Oligocene).

Irenechinus Fell, 1963 Genotype: Irenechinus hentyi Fell, 1963, Mem. Nat. Mus. Victoria. Irenechinus minor n. sp. (Plate 2, figs. 3,4),

Diagnosis. Differing from the type species in having less numerous secondary tubercles, which are arranged more densely, so as to leave no areas of smooth test between the epistromal ridges; differing also in having the epistromal ridge completely encircling the pore-pairs of each amb-element, instead of being mainly developed around the aboral and lateral margins of each pore-pair.

Holotype. Registration No. EC273, in the collection of the New Zealand Geological Survey. Horizontal diameter approximately 9 mm, height approximately 7 mm. Apical region lost. Peristome obscured. Locality. An old collection from the Trelissic Basin, Canterbury, from either the Lower Tuff's of Tuffs between limestones. Horizon. Whaingaroan-Duntroonian (Lower-Middle Oligocene).

Remarks. The species closely resembles Brochopleurus spp. but differs in having crenulate primary tubercles, the diagnostic character by which Irenechinus is distinguished from Brochopleurus. The crenulations can be observed on those primary tubercles which have not been excessively abraded or leached, and number 12-16, according to the size of the tubercles. They could not be observed on secondary tubercles. I. minor is considerably smaller than I. hentyi (h.d. 15 mm),

ai id the crowded secondaries do not form spaced series like strings of pearls, as they do in the latter. The more generalised character of I. minor is in accordance with its occurrence in an older horizon (Lower-Middle Oligocene) than that from which the Victorian species is known (Batesfordian, Lower Miocene). Despite its smaller test, I. minor has the same number of amb-plates (13-14 in each series), and interamb-plates (11 in each series) as does the larger genotype species. No other species of Irenechinus is so far known. The new species points to Brochopleurus as the probable closest relative of Irenechinus among the Temnopleuridae, and it would not be surprising if traces of crenulation will be found in one or other of the species of Brochopleurus, in much the same way as vestigial crenulation has been observed in Pseudechinus spp., the latter genus being also a suspected derivative of Brochopleurus (Fell, 1962).

A fragment of what may be an immature specimen of 1. minor, N.Z. Geol. Survey Reg. No. EC274, carries the locality Coleridge Creek, Tuff in Marl, G 53355, age Whaingaroan-Duntroonian; its identity, however, is uncertain as it is badly leached. On this smaller test, horizontal diameter ca. 7 mm, the primary tubercles of the amb are closer together, with few intervening secondaries, and the dense tuberculation is reminiscent of Arbacina, a genus from which Brochopleurus and Irenechinus might have arisen.

Order SPAT AN GO IDA Family BRISSIDAE Brissopsis L. Agassiz Subgenus Kleinia Gray, 1851 Subgenotype: Kleinia luzonica Gray, 1851

Brissopsis praeluzonica n. sp. (Plate 3, fig. 5; Plate 4, fig. 6). Diagnosis. As luzonica, but differing in having the abradial pore of each zygopore on the lateral ambs fully developed, and equal in size to the adradial pore. The anterolateral ambs are of the same length as the posterolateral ambs, but diverge laterad somewhat more strongly than in luzonica, forming an angle of approximately 50° with the anterior unpaired amb, as against about 40° in luzonica.

Holotype. Registration No. EG275, in the collection of the New Zealand Geological Survey. Length approximately 58 mm, breadth approximately 46 mm, height approximately 30 mm (estimated, the adoral surface lacking). Locality. An old collection from the Trelissic Basin, Canterbury, from either the Lower Tuffs or Tuffs between limestones.

Horizon. Whaingaroan-Duntroonian (Lower-Middle Oligocene). A second and badly crushed specimen EC276, possibly referable to the same species, is labelled as from G 55117, lower tuffs at Gorge, Broken River, Trelissic, and considered to be of the same age.

Brissopsis praeluzonica closely resembles the Recent species B. luzonica, the type of the subgenus Kleinia. The subgeneric character, namely the confluence of the posterolateral ambs, which shape a sweeping curve with the anterolateral ambs, is here developed almost exactly as in luzonica, with only the distal 6-7 zygopores developed in the inner series, where the extremity of the amb is turned outwards. The fasciole has been lost, as also the whole of the adoral surface.

Brissopsis ( Kleinia) latior Herklots, from the Miocene of Java has been considered by Mortensen (1951) as a probable ancestor of the Recent B. luzonica. The present species, of Oligocene age, has equal claim to be so regarded. B. luzonica in Recent seas ranges between the Red Sea, Mozambique, South Japan, Hawaii, Tahiti and Queensland, in depths of 10-1,000 (? 2,000) m. The Challenger record of the species from New Zealand has been shown (Fell, 1958) to be a probable misidentification of juvenile B. oldhami. The genus Brissopsis is widely represented, but is conspicuously absent from South America, as also from the Arctic and Antarctic. Its presence in the New Zealand Oligocene, and its representation then by a species so close to luzonica, must indicate an Indo-West-Pacific element in the fauna. Species of Brissopsis occur on soft bottom. The great majority of Recent New Zealand samples (of B. oldhami ) come from depths between 600 and 1,000 metres, though it ranges up to the outer part of the shelf, in 100 metres. The ecology of Brissopsis, and its fragility, would effectively exclude epiplanktonic dispersal. Hence its absence from South America and Antarctica does not imply a lack of mid-Tertiary West-Wind-Drift, but suggests an absence of bathyal dispersal routes. Ecological factors may have limited the dispersal of the other echinoids mentioned here.

Hutton (1873, p. 41) described Kleinia conjuncta from Grey River. The description, which lacks figures, suggests that the species was correctly placed in Kleinia, but does not permit closer identification for unfortunately the holotype has been lost. A supposed syntype in the collection of the N.Z. Geological Survey is an indistinct internal and external mould, and cannot be determined even to genus. In these circumstances, therefore, the specific name conjuncta is a nomen nudum.

CHECK LIST The following Oligocene echinoids are now known from the Trelissic Basin. CIDAROIDA 1. Histocidaris mackayi Fell, 1954. ( Nom. con., pro H. mckayi, as now required by Regies.) G 5243: Fan Coral Bed, coll. J. D. Enys, 1866, 1879. Isolated radicles, EC 144. Duntroonian. See Fell, H. 8., 1954, Pal. Bull. 23 (N.Z. Geol. Surv., Wellington). The species is known from other Duntroonian and Waitakian localities in the South Island.

T EMNOPLEUROIDA 2. Goniosigma enysi (Hutton, 1873), herein. 2. Goniosigma enysi (Hutton, 1873), herein. 3. Irenechinus minor n. sp., herein. Spatangoida 4. Brissopsis praeluzonica n. sp., herein.

References Fell, H. 8., 1953. Origin and Migrations of Australasian Echinoderxn Faunas. Trans. Roy. Soc. N.Z., 81 (2), 246-7. 24, 38-9. Evolution of Living Organisms (Melbourne Univ. Press). Victoria.

Hawkins, H. L., 1925. “Note” (on N.Z. Tertiary Echinoidea), in Mortensen, Th., Vid. Medd. dansk, naturh. For. Kbh., 73, 407-9. Herklots, —, 1854. Fossiles de Java; Echinoderms, p. 13. Hutton, F. W., 1873. Catalogue of the Tertiary Mollusca and Echinodermata of New Zealand (Colonial Museum, Wellington). Mortensen, Th., 1951. Monograph of the Echinoidea (Reitzel, Copenhagen), 5 (2), 397-404.

Professor H. B. Fell, Museum of Comparative Zoology, Harvard University, Cambridge 38, Mass., U.S.A.