New Species of Brachiopoda from the Torlesse Group of Kaiwara Valley, North Canterbury

Transactions of the Royal Society of New Zealand : Geology, Volume 3, Issue 7, 21 July 1965, Page 95

New Species of Brachiopoda from the Torlesse Group of Kaiwara Valley, North Canterbury

J. D. Campbell

By

[Received by the Editor, 2 November 1964.]

Abstract

Two new species are described from a rhynchonellid-terebratuloid assemblage in late Jurassic (? Puaroan) limestones of the Torlesse Group, Kaiwara Valley, North Canterbury.

Introduction

Poorly preserved brachiopods are the dominant organisms in shell limestone in Kaiwara Valley, North Canterbury. The rocks form part of the Torlesse Group and outcrop in an area in which Upper Jurassic mollusca occur (see Campbell and Warren, 1965).

SYSTEMATICS

Phylum BRACHIOPODA

Family RHYNCHONELLIDAE

Genus Burmirhynchia S.S. Buckman, 1915

Type Species: Burmirhynchia gutta Buckman, Middle or Upper Jurassic, Burma.

Burmirhynchia warreni n.sp. PI. I, Figs. 1-6; Text-fig. 1.

Holotype: CI7OO, University of Otago, Geology Department.

Paratypes: C 1697-1699, 1701-1707.

Diagnosis: Large costellate, plicate shell in which a short median deflexion develops later in ontogeny. Ventral valve much less convex than dorsal in early ontogeny; dorsal convexity increases in maturity with development of broad fold. Gostellae are initiated on umbones and persist without bifurcation; about 24 ribs are developed; individual ribs are sharply rounded. Dental plates are present and appear to diverge; ventral muscle field broadly spoon-shaped with a weak median septum. Dorsal muscle field broadly semicircular; anterior scars pyriform, slightly smaller and less impressed than posterior; fairly strong median septum.

Dimensions: Length 31mm, width 36mm, thickness 25mm (holotype).

Localities: 562/506 (type), 513, 514, 516, 517, 518: large limestone blocks probably not in place, small valley immediately north of Random Spur Road, Kaiwara Valley, North Canterbury. 562/507, 520: limestone in place, same valley.

Remarks: The material is imperfect and a full morphological account of the foramen and delthyrial regions cannot be given. Placing of the species in Burmirhynchia is therefore somewhat tentative. Ribbing is of the same general style as in Burmese species of Burmirhynchia, although the deflexion is considerably stronger in New Zealand specimens. There is fair agreement in muscle field patterns (Text-fig. 1).

The species is named in honour of Mr Guyon Warren.

Family TEREBRATULIDAE

Genus Holcothyris S.S. Buckman, 1915

Type Species : Holcothyris angulata Buckman, Middle or Upper Jurassic, Burma.

Holcothyris (?) kaiwaraensis n.sp. PI. I, Figs. 7-9; Text-fig. 2. Holotype: Cl7lO, University of Otago, Geology Department. Paratypes: Cl7ll, 1712.

Diagnosis: Large biconvex shells, uniplicate in late ontogeny. Massive ventral umbo, foramen probably large. Shell finely capillate. Dorsal valve with a weak median septum, large pyriform divergent muscle scars.

Dimensions: Length 39mm, width 34mm, thickness 23mm (holotype).

Localities: 562/518 (type), 506, 513, 514, 515, 517: large limestone blocks probably not in place, small valley immediately north of Random Spur Road, Kaiwara Valley, North Canterbury. 562/507, 519, 520: limestone in place, in same valley.

Remarks : The systematic placing of indifferently preserved terebratuloid shells is notoriously difficult and association of the present species with Holcothyris must be regarded as tentative. Such muscle field observations as the material allows are not inconsistent with the Holcothyris placing (Text-fig. 2) and the capillate shell is an additional factor in support of such a placing.

The Age of the Kaiwara Brachiopod Limestone

Burmirhynchia and Holcothyris are characteristic Upper (and, less certainly, Middle) Jurassic genera of the Tethyan province, especially in Asia (cf. Sahni, 1940 : 2). They are preserved in association in Burma and Yunnan, and they are both recorded from Japan. Whereas undoubted Holcothyris is not known elsewhere, species of Burmirhynchia have also been described from India, Africa and Europe.

In so far as the generic placings of warreni and kaiwaraensis are reliable they support a late Jurassic age for the Kaiwara brachiopod limestone. Better-known mollusca of Puaroan (uppermost Jurassic) age are recorded (see Campbell and Warren, 1965) from several associated limestone localities in Kaiwara Valley (for example 562/781).

References

Buckman, S. S., 1915. The Brachiopoda of the Namyau Beds of Burma, Preliminary Notice. Rec. geol. Surv. Ind., 45(1): 75-81.

Buckman, S. S., 1917. The Brachiopoda of Namyau Beds, Northern Shan States, Burma. Pal. Ind., New series 3(2): 254 pp., 21 PL

Campbell, J. D., and Warren, G., 1965. Fossil Localities of the Torlesse Group in the South Island. Trans, roy. Soc. N.Z., Geol. 3(8): 99-137, Pis. 1-5.

Muir-wood, H. M., 1934. On the Internal Structure of Some Mesozoic Brachiopoda. Phil. Trans, roy. Soc. London, 8.233: 511-567.

Reed, F. R. C, 1929. Palaeozoic and Mesozoic Fossils from Yun-nan. Pal. Ind., New series 10(1): 291 pp. 20 PL

Sahni, M. R., 1940. The Jurassic Brachiopoda of the Namyau Beds of the Northern Shan States, Burma. Pal. Ind., New series 30(1): 39 pp., 4 PL

Tokuyama, A., 1957. On some Jurassic Rhynchonellids from Shikoku, Japan, Trans. Proc. pal. Soc. Japan, 28: 28-36.

Tokuyama, A., 1959. Bemerkungen über die Brachiopodenfazies der oberjurassischen Torinosuserie Sudwestjapans, mit Beschreibungen einiger Formen. Jap. J. Geol. Geogr., 30: 183-194, PL 25.

J. D. Campbell, Geology Department, University of Otago, Dunedin, New Zealand.