Go to National Library of New Zealand Te Puna Mātauranga o Aotearoa
Volume 81, 1953
This text is also available in PDF
(737 KB) Opens in new window
– 303 –

Some New Zealand Tertiary Marine Ostracoda Useful In Stratigraphy.

[Read before Geology Section, Wellington Branch, October 9, 1952; received by Editor, October 20, 1952.]

Summary

The following twelve new species of Tertiary marine Ostracoda are described and their known ranges given: Macrocypris eocuneata (lower Eocene to lower Oligocene). Cytheridea (Clithrocytheridea) marwicki (upper Oligocene), Protocythere hayi (middle to upper Eocene), Leptocythere kaiata (upper Eocene), Cytheralison amiesi (lower Oligocene), Bythocythere ferox (upper Eocene to upper Pliocene), Cythereis semicontigua (lower Eocene? to lower Oligocene), Trachyleberis proterva (lower to upper Eocene), Bradleya kaiata (upper Eocene), Quadracythere chattonensis (lower to middle Oligocene), Hemicythere parvitenuts (upper Eocene). Cauditcs impostor (lower to middle Eocene).

Introduction

When the author started work on the Ostracoda in 1946 it was hoped that they would prove useful in New Zealand stratigraphy. Although the group was found to be generally inferior to the Foraminifera in stratigraphic work, many useful species had been discovered by 1950 and were incorporated in N.Z. Geological Survey Paleontological Bulletin 18, “Tertiary and Recent Marine Ostracoda of New Zealand,” published in 1952.

Subsequent work has brought to light other species of limited stratigraphic range, and the present paper describes twelve new species of Ostracoda, selected for their promise as stratigraphic indicators. Kaiatan-Runangan (upper Eocene) ostracod assemblages, in particular, are found to be a well-defined faunal unit.

Figures and descriptions are reduced to the minimum adequate for identification. Where interior characters are not illustrated or discussed, it is to be assumed that they comply with the diagnoses given in NZ. Geological Survey Paleontological Bulletin 18.

All figures were drawn by the author with the and of a camera lucida. Measurements were made with a measuring ocular.

Types are deposited with the N.Z. Geological Survey collections.

Wherever possible, collections are located by National Provisional One Mile Sheet grid references.

Systematics

Macrocypris eocuneata Hornibrook, n.sp. Text-Fig. 1, Fig. 6.

1952. Macrocypris elongate sp., Hornibrook, N.Z. Geol. Surv. Pal. Bull. 18, p. 19.

Carapace elongate, cuneate, of medium size, moderately inflated; shell walls thick and heavy, smooth and glossy; anterior margin evenly rounded and somewhat compressed; posterior margin highly compressed and pointed; dorsal margin arched and sloping strongly backwards for two-thirds of its length; ventral margin slightly sinuous.

– 304 –
Picture icon

Text-Fig. 1. (Magnifications, approximate.).—Protocythere hayi Hornibrook, n.sp., Figs. 1, 4. Fig. 1: Left valve, holotype; × 60. Fig. 4: Hinge and muscle scars of right valve (F5888, Maheno). Cytheridea (Clithrocytheridea) marwicki Hornibrook, n.sp. Figs. 2, 3, 8.—Fig. 2: Left valve, holotype (female); × 60. Fig. 3. Right valve, paratype (male), interior aspect; × 60. Fig. 8: Left valve, holotype, dorsal aspect; × 60. Leptocythere kaiata Hornibrook, n.sp. Fig. 5.—Left valve, holotype; × 135. Macrocypris eocuneata Hornibrook, n.sp. Fig. 6: Left valve, holotype; × 60. Hemieythere parvitenuis Hornibrook, n.sp. Fig. 7: Left valve, holotype, × 60. Cytheralison amiesi Hornibrook, n.sp., Figs. 9, 10.—Fig. 9: Right valve, holotype; × 60. Fig 10: Right valve, holotype, interior aspect; × 60.

– 305 –

Holotype: A left valve. L. 1.62 mm.; H. 0.64 mm.; W. 0.35 mm.

Locality: F5890, Oamaru S.D., Grid Ref. S136/437583, chalk marls below limestone, Clark's flour mill, left bank of Kakanui River, 3/4 mile N.E. from Maheno.

Type Level: Runangan (upper Eocene).

Remarks: Distinguished from other New Zealand species of Macrocypris by the compressed and pointed shape of the posterior two-thirds of the shell.

Range: First found in the Dannevirke Series (lower Eocene), common in the Bortonian and Runangan (middle and upper Eocene), lasting to the Whaingaroan (lower Oligocene).

Cytheridea (Clithrocytheridea) marwicki Hormbrook, n.sp Text-Fig. 1, Figs. 2,3,8.

Carapace suboval in females, elliptical in males, of medium size, strongly inflated; walls moderately thick and heavy; anterior margin broadly rounded or compressed; posterior margin compressed and slightly downwardly hooked; dorsal and ventral margins parallel, ornamented dorsally and dorso-laterally with a subdued reticulate surface pattern modified anteriorly, ventrally, and posteriorly as ridges running parallel to the margins; a slight but distinct dorso-lateral sulcus, slightly anterior to the mid line; hinge consisting in the right valve of long cusped teeth connected by a deep, finely crenulate groove; left valve complementary, with a prominent median crenulate bar; radial canals numerous around the anterior margin, line of concrescence coinciding with inner margin.

Holotype: A left valve. L. 0.89 mm.; H. 0.47 mm.; W. 0.23 mm.

Locality: F.7615 (G.S.5590), soft fine brown grey sandstone in terrace face behind house with Pinus radiatus, 80–90 chs. west of Sutherlands railway station, Pareora S.D., Grid Ref. S111/c586676.

Type Level: Awamoan (upper Oligocene).

Remarks: Named after Dr. J. Marwick, who made the collection from Sutherlands. Plainly distinguished from the other two New Zealand species of Cytheridea (C. mosaica Hornibrook, C. aoteana Hornibrook) by both shape and surface pattern. C. mosaica evidently belongs to Hemicytheridea (Kingma, 1948) but authors are not unanimous as to the status of the hinge-groups within Cytheridea, treated here as subgenera. The Recent species, C. aoteana, is now known to occur with Quadracythere chattonensis n.sp. and a Waitakian (middle Oligocene) foraminiferal fauna, in collection S178/f498, Lindhurst S.D., Southland.

Range: Known only from Sutherlands and White Rock River, South Canterbury, in a shallow water, sandy facies of the Hutchinsonian or Awamoan (upper Oligocene).

Protocythere hayi Hornibrook, n.sp. Text-Fig. 1, Figs. 1, 4.

Carapace large, subtriangular, strongly inflated; walls heavy and strong; anterior margin high and broadly rounded, weakly but distinctly crenulate; posterior margin strongly compressed, shaped somewhat like a blunt arrowhead; dorsal margin short, sloping strongly backwards; postero-dorsal angle prominent; ventral margin rounded, with a few blunt denticulations; surfaces nearly smooth, with a few rows of faint, shallow pits, more prominent in the inflated median area of the shell; a vertical row of four muscle scars behind a single crescentic scar; hinge consisting in the right valve of two prominent smooth (?) terminal teeth connected by a groove.

– 306 –

Holotype: Valves attached. L. 1.15 mm.; H. 0.71 mm.; W. 0.51 mm.

Locality: F7384, N10/f550, Grid Ref. N10/141581, Maungataniwha S.D., grey mudstone at junction of Paiokatutu Stream and a tributary.

Type level: Kaiatan (upper Eocene).

Remarks: Although this species occurs commonly with the valves cemented together, perfect single valves are rarely found. In the two single valves available (one left and one right valve), it could not be determined with certainty whether the hinge teeth and connecting bar were smooth or crenulate, although the teeth appeared to be smooth. The species is tentatively placed in Triebel's genus Protocythere (with terminal denticulate areas and strongly serrate connecting bar) with which it seems to have its closest affinities. Details of the inner marginal areas were not observed. Named after Mr. R. F. Hay, New Zealand Geological Survey district geologist, who made the collection from which the species is described.

Range: Known only in the Eocene. Occurs in the upper Bortonian (middle Eocene) Hurunui Chalk Marls, in the Runangan at Maheno and in Kaiatan-Runangan (upper Eocene) microfaunas in the Kaeo district, North Auckland.

Leptocythere kaiata Hornibrook, n.sp. Text-fig 1, Fig. 5.

Carapace subrectangular, small; anterior margin high and broadly rounded; slightly crenulate; posterior margin square and truncate; dorsal margin distinctly arched; surfaces appearing crinkled, with a distinctive pattern of sinuous swollen ribs.

Holotype: A left valve. L. 0.32 mm.; H. 0.23 mm; W 0.12 mm.

Locality: F5182, Oamaru S.D., Grid Ref. S136/473674, Jackson's paddock, 1 mile S.W. of Cormacks Railway Station, lower part of limestone.

Type Level: Runangan (upper Eocene).

Remarks: There are several species of Leptocythere in New Zealand with crinkled shells like L. kaiata which is plainly distinguished by its distinctive surface pattern.

Range: Like Hemicythere parvitenuis n.sp., L. kaiata is an index species of the Kaiatan and Runangan (upper Eocene) and nearly always accompanies parvitenuis.

Cytheralison amiesi Hornibrook, n.sp. Text-Fig. 1, Figs. 9, 10.

Carapace oblong-ovate, of modern size, strongly inflated; walls moderately thick; anterior margin broadly rounded with a strong flange and two or three spines; posterior margin broadly rounded and a little more compressed; dorsal margin straight, sloping backwards; ventral margin slightly rounded; shell consisting of a honeycomb of subsurface cells with slit-openings, one large subcentral cell opposite the muscle scars; armed with two prominent, backwardly-inclined spines, one postero-lateral in position, the other adjacent to the posterior margin.

Holotype: A left valve, L. 0.89 mm.; H. 0.49 mm.; W. 0.28 mm.

Type Locality: F6597, Grid Ref. S127/c292883, greensand at base of limestone escarpment at junction of roads leading to Tokarahi, Prydes Gully, and Ngapara.

Type Level: Duntroonian (lower Oligocene).

Remarks: Named after the late A. C. Amies, whose collections from a section near Riverside, in the Hakataramea Valley, established the range of this species.

– 307 –

Distinguished from other New Zealand species of Cytheralison mainly by the prominent posterior spines.

Range: So far, C. amiesi is known only from the Hakataramea Valley, where it is confined to the Duntroonian. At the type locality it is abundant in the Duntroonian greensand and overlying limestone, where it is accompanied by abundant Foraminifera and Ostracoda, including Bradleya proarata Hornibrook, Cythereis hostizea Hornibrook and Cytheralison n.sp. aff. fava Hornibrook. In a large microfauna in the loose brown weathered mudstone of Waitakian age, above the limestone, the first two species and C. amiesi disappear but C. aff. fava remains abundant.

Bythocythere ferox Hornibrook, n.sp. Text-Fig. 2, Fig. 1.

Carapace large, strongly inflated with a broad median sulcus; walls thick and heavy; anterior margin broadly rounded with numerous flattened denticulations; posterior margin compressed and slightly upturned, with flattened denticulations along the lower half; dorsal margin short and straight, ventral margin rounded and denticulate; ventro-lateral swellings bearing a row of prominent, flattened peg-like spines with another shorter row below; a short row of about four spines lies above the muscle scars, just below the dorsal margin; surfaces otherwise smooth and glossy with numerous normal pore canals; a row of five muscle scars situated in the median sulcus; hinge consisting in the left valve of a slightly arched, simple bar fitting into a complementary groove in the right valve; the upper anterior and posterior margins of the left valve overlap those of the right valve.

Holotype. A left valve. L. 1.24 mm; H 0.64 mm.; W. 0.42 mm.

Locality: F 5125, Papakaio S.D., S128, road cutting at Pukeuri.

Type Level: Awamoan (upper Oligocene).

Remarks: Seems to have affinities with Miracythere but has the more simple hinge pattern of Bythocythere.

Range: Common in the middle Oligoeene (Waitakian and Otaian) but known also from the Runangan (upper Eocene) at Cormacks, and occurs rarely as late as Castlecliffian (upper Pliocene). Not known in the Recent.

Cythereis semicontigua Hornibrook, n.sp. Text-Fig. 2, Fig. 9.

1952. Cythereis contigua (in part), Hornibrook, N.Z. Geol. Surv. Pal. Bull. 18, p. 36.

Carapace subquadrate, rather small, very weakly inflated; shell walls thick and heavy; anterior margin broadly rounded, slightly crenulate; posterior margin squarish, more compressed; dorsal margin straight, sloping backwards; ventral margin straight; antero-dorsal and postero-dorsal angles prominent in left valve; surfaces ornamented with an obscure pattern of weak reticulate ridges with a broader, raised area below the antero-dorsal angle.

Holotype: A left valve. L. 0.75 mm.; H. 0.47 mm.; W. 0.19 mm.

Locality: F 5047, Oxford Chalk, North Canterbury.

Type Level: Whaingaroan (lower Oligocene).

Remarks: Close to Cythereis contigua with which it was at first confused, but distinguished by the smaller, less inflated, squarer shell with an obscure but distinctive surface pattern.

– 308 –
Picture icon

Text-Fig. 2 (Magnifications approximate).—Bythocythere ferox Hornibrook, n.sp. Fig. 1: Right valve, holotype; × 60. Caudites n. sp. Fig. 2: Left valve (lower greensand, Christies Bench, Port Naorlunga, South Australia); × 60. Caudites impostor Hornibrook, n.sp., Figs. 3-5. Fig. 3: Left valve, holotype; × 60. Fig. 4: Right valve, paratype; interior aspect; × 60. Fig. 5: Left valve, holotype, dorsal aspect; × 60. Bradleya kaiata Hornibrook, n.sp., Figs. 6, 10. Fig. 6: Left valve, holotype; × 60. Fig. 10: Left valve, holotype, dorsal aspect, × 60. Trachyleberis proterva Hornibrook, n.sp. Fig. 7: Left valve, holotype; × 60. Quadracythere chattonensis Hornibrook, n.sp., Figs. 8, 11. Fig. 8: Left valve, holotype; × 60. Fig. 11: Left valve, holotype, dorsal aspect; × 60. Cythereis semicontigua Hornibrook, n.sp. Fig. 9: Left valve, holotype; × 60.

– 309 –

Range: Common in the Whaingaroan and very characteristic of this stage, but found also in the Bortonian (Hurunui Chalk Marls) and probably in the Dannevirke Series. Not known later than Whaingaroan.

Trachyleberis proterva Hornibrook, n.sp. Text-Fig. 2, Fig. 7.

Carapace rather small, moderately inflated; shell walls moderately thick and strong; anterior margin broadly rounded and finely denticulate; posterior margin upswept and bluntly rounded; dorsal margin slightly downwardly curved, with a number of short, blunt spines; antero-dorsal angle prominent; ventral margin slightly rounded; subcentral tubercle distinct; surfaces mainly smooth and glossy but with short, blunt tubercles, mostly aligned along the ventro-lateral swellings and along the anterior margin.

Holotype: A left valve. L. 0.51 mm.; H. 0.38 mm.; W. 0.19 mm.

Locality: Cape Foulwind, micaceous soft muddy siltstone about 280 feet above basement, Steeples S.D., Grid Ref. S23/c975735.

Type Level: Runangan (upper Eocene).

Remarks: Distinguished mainly by the upswept posterior margin and the distribution of the tubercles. Trachyleberis seems to contain at least two distinct lineages in New Zealand, probably unworthy of systematic rank. On one hand there is a group of large, strong-spined species including T. tridens Hornibrook, T. thomsoni Hornibrook, T. scabrocuneata (Brady) and other species as yet undescribed, and on the other hand, a group of small, short-spined species of which T. proterva, T. rugibrevis Hornibrook, T. probesioides Hornibrook, and T. brevicosta Hornibrook are typical.

Range: T. proterva ranges throughout most of the Eocene, for which it seems to be a key species. It occurs in the Dannevirke Series (lower Eocene) and is common in the Bortonian (middle Eocene) and especially in the Kaiatan and Runangan (upper Eocene) (e.g., the Maheno Chalk Marls). In the section at Cape Foulwind on the West Coast, T. proterva is present in the Runangan but disappears at the level where the foraminiferal assemblages become transitional Runangan-Whaingaroan.

Bradleya kaiata Hornibrook, n. sp. Text-Fig. 2, Fig. 6.

Carapace of medium size, strongly inflated, subrectangular; walls moderately thick and heavy; anterior margin broadly rounded; lower half of posterior margin projecting ventrally and bearing four strong, blunt denticulations; dorsal and ventral margins straight and parallel; shell strongly alate with a well-developed ventro-lateral keel and distinct subcentral tubercle; ornament consisting of an obscurely radiate pattern of fine reticulate ridges; a distinct eye tubercle at the antero-dorsal angle.

Holotype: A left valve. L. 0.81 mm.; H. 0.40 mm.; W. 0.31 mm.

Locality. Cape Foulwind, micaceous soft muddy siltstone, 280 (plus) feet above basement, Steeples S.D., Grid Ref. S 23/c975735.

Type Level: Runangan (upper Eocene).

Remarks: Distinguished by the subrectangular, strongly alate shell with a distinct subcentral tubercle, obscurely radiate reticulate surface pattern, and spined denticulate posterior margin.

Range: Apparently a key species for the Kaiatan and Runangan (upper Eocene). Occurs in the Kaiatan and Runangan in the Point Elizabeth and Cape

– 310 –

Foulwind sections on the West Coast, in the Kaiatan below the limestone at Fortification Hill, Oamaru, and in at least one Kaiatan fauna (N 11/f525) in the Kaeo district, North Auckland.

Quadracythere chattonensis Hornibrook, n.sp. Text-Fig. 2, Fig. 8.

Carapace subquadrate, of medium size; moderately inflated; walls thick and heavy; anterior margin broadly rounded, finely crenulate, sloping slightly upwards and backwards; posterior margin produced as a blunt caudal process bearing 6-7 small, blunt spines; dorsal margin short, with a slight backwards slope; ventral margin gently rounded; surfaces ornamented with strong, exaggerated, reticulate ridges; dorso-lateral keel distinct; ventro-lateral keel prominent, middle rib distinct; a distinct flange along the upper, outer half of the anterior margin; eye tubercle prominent.

Holotype: A left valve. L. 0.92 mm.; H. 0.51 mm.; W. 0.24 mm.

Locality: F5368, (G.S. 1846), Chatton S.D., Grid Ref. S170/811576, sandstone, 55 ch. S.E. from Trig F.

Type Level: Duntroonian (lower Oligocene).

Remarks: This highly distinctive Quadracythere is plainly distinguished from most other New Zealand species by the highly exaggerated ornament, open and radiate around the anterior margin.

Range: Known only from Southland and highly characteristic of the Duntroonian shell sands of the Chatton district. The only other known occurrence is in sample S178/f498 (F6366), Grid Ref. 763265, Lindhurst S.D., 260 ch. at 123deg. from Trig. R496', on the west bank of the Mataura River, 1.8 miles downstream from the bridge, with a Waitakian formainiferal fauna, apparently of shoreline facies.

Hemicythere parvitenuis Hornibrook, n.sp Text-Fig. 1, Fig. 7.

Carapace subrectangular, rather small, moderately inflated; walls thick and strong; subcentral tubercle prominent; eye tubercle distinct; anterior margin broadly rounded; antero-dorsal angle prominent; posterior margin produced as a blunt, but distinct, caudal process bearing four small spines; dorsal margin slightly arched; postero-dorsal angle prominent in the left valve; ventral margin slightly arched; ventro-lateral keel distinct and blunt; dorso-lateral keel rather obscure, ending in a strong, blunt projection; surfaces smooth; normal pores numerous and distinct; radial pore canals exceedingly numerous, especially around the anterior margin.

Holotype: Valves attached. L. 0.58 mm.; H. 0.28 mm.; W. 0.24 mm.

Locality: F 5890, Oamaru S.D., Grid Ref. S136/437583, chalk marls below limestone, Clark's flour mill, left bank of Kakanui River, 3/4 mile N.E. from Maheno.

Type Level: Runangan (upper Eocene).

Remarks: Distinguished from other New Zealand species of Hemicythere by the elongate subrectangular, smooth shell with distinct, blunt ventro-lateral keels, distinct dorso-lateral projections, and prominent subcentral tubercle.

Range: Apparently an index of the Kaiatan and Runangan Stages (upper Eocene). Common in the Kaiata Mudstone and at most Runangan localities, associated with Trachyleberis proterva n.sp., Quadracythere radizea Hornibrook, Q. quadrazea Hornibrook, Bradleya kaiata n.sp.; B. proarata Hornibrook, Leptocythere kaiata n.sp., etc.

– 311 –

Caudites impostor Hornibrook, n.sp. Text-Fig. 2, Figs. 3-5.

Carapace tiny, subquadrate; walls moderately thick and strong; anterior margin broadly rounded and distinctly crenulate; posterior margin squarely truncate; dorsal margin slightly curved; ventral margin slightly arched; subcentral tubercle prominent; a prominent dorso-lateral keel ornamented with large tubercles; a prominent ridge connects the antero-dorsal and antero-ventral angles; hinge consisting in right valve of an anterior Bradleya-type, pseudosimple tooth and post-adjacent socket, a crenulate posterior tooth and smooth (?) connecting groove.

Holotype: Valves attached.L. 0.47 mm.; H. 0.28 mm.; W. 0.12 mm.

Locality: F 5570, Grid Ref. S62/391354, Lowry Peaks S.D., chalk marls below Amuri Stone, Hurunui River, 1/2 mile S.W. Trig. B.

Type Level. Heretaungan (lower Eocene).

Remarks: Evidently related to a more advanced species of Caudites (Text-Fig. 2, Fig. 2) that occurs in the lower greensand at Christies Beach, Port Naorlunga, South Australia, and is therefore included in that genus. Well preserved specimens are difficult to obtain and the muscle scars and inner marginal area have not been observed.

Range: Known only at the type locality where it occurs with Heretaungan (lower Eocene) and Bortonian (middle Eocene) Foraminifera.

References

Hornibrook, N. De B., 1952. Tertiary and Recent Marine Ostracoda of New Zealand. N.Z. Geol. Surv. Pal. Bull. 18.

Kingma, J. T., 1948. Contributions to the knowledge of the Young-Caenozoic Ostracoda from the Malayan region. Kemink Printers, Utrecht.