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Volume 63, 1934
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The Genus Liothyrella (Brachiopoda) in New Zealand.
[With 3 plates.]

[Read before the Otago Institute, 11th November, 1930.]

It has been shown by J. Allan Thomson (1927, pp. 196–8) that the New Zealand Tertiary Terebratulids referred by him to Liothyrella are not uniform as regards loop-characters; some species approach the Liothyrella-type, while others agree more closely with the Gryphus-type of loop. The genotypes of Liothyrella Thomson, and Gryphus Megerle von Muhlfeldt (see Thomson, 1927, for details), are not available to the writer, and in this revision the whole of the New Zealand species, Recent and Tertiary, are referred to Liothyrella sensuo lata.

Liothyrella J. A. Thomson 1916.

1916. Liothyrella Thomson, Trans. N.Z. Inst., 48 (Oct. 16), p. 44.

1918. Liothyrella Jackson, Geol. Mag., Dec. 6, vol. 5, pp. 73–79.

1927. Liothyrella Thomson, N.Z. Board Sci. and Art, Man. No. 7, pp. 197–8.

Type (by original designation): Terebratula uva Broderip 1833 (see Thomson, 1927, p. 197, fig. 59).

Generic Diagnosis: Ovate, biconvex Terebratulidae which are uniplicate to sulciplicate; test smooth, finely punctate. Beak short, foramen epithyrid, marginate to labiate, symphytium almost hidden. Hinge-teeth without dental plates or swollen bases. Hinge-plates divided; cardinal process small, transverse. Loop short, triangular, the descending branches diverging anteriorly and meeting the transverse band in a sharply pointed angle.

Specific Characters: In the specific descriptions which follow, it will not be necessary to repeat what already appears in the generic diagnosis above. The introductory word “Liothyrella” implies that the species conforms to the generic description given.

The features of specific importance are:—(1) Shape and size; (2) relative convexity of the valves; (3) degree of foraminal development; (4) the stage of evolution reached by the anterior commissure, i.e., the folding; and (5) the detailed nature of the loop.

This specific revision includes the species previously described by Suess, Hutton, Hamilton, Boehm, and Thomson, viz.:—

  • Waldheimia gravida Suess 1864.

  • Waldheimia concentrica Hutton 1873.

  • Terebratula oamarutica Boehm 1904.

  • Terebratella kakanuiensis Hutton 1905.

  • Terebratella neglecta Hutton 1905.

  • Magellania magna Hamilton 1910.

  • Liothyrella boehmi Thomson 1918.

  • Liothyrella landonensis Thomson 1918.

  • Liothyrella neozelanica Thomson 1918.

  • Liothyrella pulchra Thomson 1918.

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The whole of these species were described in manuscript left by J. A. Thomson, and written during, or prior to, 1918. I have to thank Mr W. R. B. Oliver, Director of the Dominion Museum, for permission to make use of this valuable manuscript. The actual descriptions needed careful editing, and could not be used without considerable addition and emendation, but nevertheless were invaluable to a student beginning to study Tertiary brachiopoda. Actually the specific diagnoses which follow, while they owe much to the late Dr Thomson's preliminary work, are based almost entirely on personal study of genotypes or topotypes.

For permission to redescribe the types of Hutton's species, the writer must thank Professor R. Speight, Curator of the Canterbury Museum. Mr W. R. B. Oliver has kindly forwarded the types of the species described by A. Hamilton and J. A. Thomson.

Terebratula oamarutica Boehm has been studied in the form of topotypes. Waldheimia gravida Suess, of which the type is in Vienna, and of which topotypes are not available, must remain an unsatisfactory species.

The new species result from the study of material collected by Dr J. Marwick and the writer from the Chatham Islands in 1924–1925; and of additional specimens collected by the writer in Otago and Canterbury.

Description of Species.

Liothyrella boehmi J. A. Thomson 1918. (Pl. 3, Fig. 5).

1918. Liothyrella boehmi Thomson, in J. Park, N.Z. Geol. Surv. Bull. No. 20, p. 118, not figured.

Diagnosis: A Liothyrella of large size (about the size of L. gravida, larger than L. concentrica and L. oamarutica, but considerably smaller than L. magna); greatest breadth anterior to the middle; ratio of length to breadth, 1 : ·77; in shape elongate-ovate; anterior commissure broadly uniplicate; beak prominent, obliquely truncated by a large foramen which is broadly marginate, and may show incipient labiation; valves strongly biconvex.

Dimensions of holotype: Length, 52mm.; breadth, 40mm.; thickness, 32mm.

Type locality: Tuffs underlying limestone, Everett's Quarry, Kakanui. Collected by A. McKay, 1882. Middle Ototaran.

Type in the Dominion Museum, Wellington.

Distribution: Material from the following localities has been examined:—

  • (a) Calcareous tuffs, Trig. M., near Totara; not uncommon. Age: Lower Ototaran. Coll. R.S.A.

  • (b) Tuffs below limestone, Flume Creek, Papakaio. Age: Middle Ototaran. (See J. Park, 1923, pp. 80–2).

  • (c) Limestone, Upper Target Gully, Oamaru. Age: (?) Upper Ototaran. R.S.A. coll.

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  • (d) Conglomerate, Rifle Butts. Age: Basal Hutchinsonian. R.S.A. coll.

  • (e) Conglomerate, coast north of Kakanui. Age: Basal Hutchinsonian. (Common). R.S.A. coll.

Remarks: The type is slightly damaged on one side, and has part of the ventral shell missing; it is not a fully adult specimen. The species is not uncommon at the type locality, but it is extremely difficult to extract from the tough matrix. L. boehmi appears to range throughout the Ototaran, but the writer has not been able to find a single specimen in the Upper Ototaran of Kakanui (Everett's Quarry). Thomson (1926, p. 152) has recorded “Liothyrella cf. boehmi” from the landonensis-fauna of Landon Creek and Flume Creek, but the species is not-known to occur in the Waitaki limestone (Waitakian). This fact makes its presence in the basal Hutchinsonian conglomerate a matter of suspicion. Concerning the basal Hutchinsonian localities, J. A. Thomson wrote: “Large specimens of Liothyrella occur in most localities [All Day Bay, Kakanui, Deborah, Ardgowan, Hutchinson's Quarry, and Devil's Bridge], and were previously referred to L. boehmi, but the best preserved specimens are broader and less convex than that species, and probably a distinct species.” (1926, p. 150). Thomson may be correct, but my own collection from the Rifle Butts, and Kakanui, does not bear out his contention. The basal Hutchinsonian specimens are, therefore, referred to L. boehmi, with the suggestion that they may be derived fossils of Ototaran age (cf. Thomson, 1926, p. 154). If they are not derived then the species has a curious discontinuous vertical range. It is not known outside the Oamaru district.

Liothyrella concentrica (F. W. Hutton 1873). (Pl. 1, Fig. 4).

1873. Waldheimia concentrica Hutton, Cat. Tert. Moll. Ech. N.Z., pp. 35–6, not figured.

1905. Terebratula concentrica Hutton, Trans. N.Z. Inst., 37, p. 474, pl. XLV, fig. 1.

Diagnosis: A Liothyrella like oamarutica (Boehm), but differing in the greater elongation (ratio of length to breadth, 1 : ·64); and in the narrowly marginate foramen, the anterior part of which projects dorsally of the hinge-line.

Type locality: Hutton (1873) gave the following localities: Chatham Islands, Broken River (lower beds), Culverden, Pakau, and Castle Point. In 1905 he figured two specimens from Broken River, which is therefore selected as the type locality.

Lectotype: The material from Broken River studied by Hutton (1905) consists of two specimens which may be regarded as syntypes. One (Hutton, 1905, pl. XLV, fig. 1, upper figure) is distorted, and part of the ventral valve is missing; the other (Hutton, 1905, pl. XLV, fig. 1, lower figure) is complete, and is therefore selected as lectotype.

Lectotype in the Canterbury Museum.

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Dimensions of lectotype: Length, 37mm.; breadth, 24mm.; thickness, 19mm.

Liothyrella gravida (E. Suess, 1864). (Pl. 1, Fig. 2).

1864. Waldheimia gravida Suess. In K. A. Zittel, Novara Exped., Geol. Theil., Bd. 1, Abth. II, Paläont. von Neu-Seeland, pp. 56–7, taf. IX, figs. 5a, b.

Type locality: Papakura limestone quarry, near Auckland.

Type in the K.-K. Hofmuseum, Vienna.

Remarks: Suess figured the interior and exterior of a ventral valve, but the interior is filled with matrix. Thomson (in MSS.) records that attempts made by Dr. C. A. Cotton, Professor J. A. Bartrum, and Mr. E. de C. Clarke to secure topotypes have so far failed. It is a matter of regret that this species must be left in an unsatisfactory position.

Provisional Diagnosis: A Liothyrella of large size in which the length is only slightly greater than the breadth, and in which the foramen is strongly labiate.

Distribution: Specimens agreeing with the type are not known to me from New Zealand proper, but material collected from a calcareous tuff at Momoe-a-Toa, Chatham Islands, agrees in size, shape, and labiation with the species illustrated by Suess, and may be referred, temporarily at least, to L. gravida (Suess). The shell from Momoe-a-Toa is figured on pl. 1, Fig. 2. The dimensions are: length, 45mm.; breadth, 41mm.; thickness, 24mm.

Liothyrella kakanuiensis (F. W. Hutton 1905). (Pl. 3, Fig. 3).

1905. Terebratella kakanuiensis Hutton, Trans. N.Z. Inst., 37 (June), p. 479, not figured.

Not T. kakanuiensis Thomson, Trans. N.Z. Inst., 40, 1908, p. 102, pl. XIV, figs. 4 a-c (not of Hutton) = Magella carinata Thomson 1915.

Diagnosis: A Liothyrella of small size which is distinctly longer than broad (ratio 1 : 7), is strongly inflated, and has an erect beak.

Dimensions of lectotype: Length, 10mm.; breadth, 7mm.; thickness, 6mm.

Type locality: Kakanui. Probably from the Kakanui limestone (Upper Ototaran), where it is common; but possibly (Thomson MSS.) from the underlying tuffs.

Lectotype: (Selected from two syntypes) in the Canterbury Museum.

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Liothyrella landonensis J. A. Thomson 1918. (Pl. 3, Fig. 2).

1918. Liothyrella landonensis Thomson, in J. Park, N.Z. Geol. Surv. Bull. No. 20, p. 118, not figured.

Diagnosis: A Liothyrella like neglecta but slightly larger, broader, more depressed, with the greatest breadth about the middle, and a suberect beak.

Dimensions of holotype: Length, 16mm.; breadth, 14mm.; thickness, 8mm.

Type locality: Glauconitic sandstone, Landon Creek, Oamaru. Collected by G. H. Uttley.

Type in the Dominion Museum, Wellington.

Distribution: L. landonensis Thomson is the index fossil of the landonensis-fauna of Thomson (1926, p. 153). The association includes Aetheia gualteri (Morris), Terebratulina suessi (Hutton), Stethothyris tapirina (Hutton), Rhizothyris dwarf spp. and Pachymagas of the ellipticus series, as well as the index fossil and some other species of rarer occurrence. Thomson (1926) was inclined to regard this assemblage as a facies fauna of Upper Ototaran age, but it seems probable that it is restricted to strata which are post-Ototaran but pre-Waitakian in age. L. landonensis itself is recorded by Thomson (1926, p. 152, table) from the following additional localities:—

(1)

Greensands, base of Maerewhenua limestone, Duntroon (J. A. Thomson coll.).

(2)

Glauconitic limestone, base of Waihao limestone, quarter-mile below Waihao Forks. (Coll. J. A. Thomson).

(3)

Upper part of Waihao limestone (Coll. R. S. Allan).

(4)

Middle and upper part of Pareora limestone, Squire's Farm, Little Pareora River. (Coll. M. C. Gudex).

Liothyrella magna (A. Hamilton 1910). (Pl. 2, Fig. 1).

1910. Magellania magna Hamilton, in E. J. H. Webb, N.Z. Geol. Surv. Bull. No. 11 (N.S.), p. 18, not figured.

Diagnosis: A Liothyrella of very large size which is broader than long and relatively depressed, and in which the beak is truncated at right-angles to the length by a large, narrow, strongly labiate foramen.

Dimensions of lectotype (a dorsal valve): Length, 75mm.; breadth, 85mm.; approximate thickness of valve, 20mm.

Lectotype (selected from 8 syntypes by J. A. Thomson): A fairly well-preserved dorsal valve, with the interior filled with a tough, impure, gritty limestone which obscures the cardinalia. Preserved in the Dominion Museum, Wellington.

Type locality: On the beach south of Little Wanganui River, Kongahu S.D. (Lower Kongahu Formation).

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Liothyrella neglecta (F. W. Hutton 1905). (Pl. 2, Fig. 2).

1905. Terebratella neglecta Hutton, Trans. N.Z. Inst., 37 (June), p. 479, pl. XLVI, fig. 3.

Diagnosis: A Liothyrella of small size which is broadly ovate (ratio of length to breadth, 1 : 78), depressed, and has a suberect beak.

Type locality: Curiosity Shop, Rakaia River, Canterbury.

Dimensions of lectotype: length, 11·5mm.; breadth, 9mm.; thickness, 5mm.

Lectotype (selected from four syntypes) in the Canterbury Museum.

Liothyrella neozelanica J. A. Thomson 1918. (Pl. 3, Figs. 1 and 4).

1918. Liothyrella neozelanica Thomson, Austral. Ant. Exp., 1911–14, Scient. Repts., Ser. C., Zool., vol. IV, pt. 3 (June 1), pp. 17–19, pl. XVI, figs. 36–8; pl. XVII, figs. 51–2; pl. XVIII, figs. 61, 62, 64.

1927. Liothyrella neozelanica Thomson, N.Z. Board Sci. and Art, Man. No. 7, pl. 1.

Diagnosis: A Recent Liothyrella very similar in shape and size to gravida (Suess)*, but not quite so broad and of slightly greater convexity; foramen as in gravida, but with a slightly shorter loop in which the descending branches diverge to a smaller degree.

Dimensions of holotype: Length, 47mm.; breadth, 42mm.; thickness, 29mm.

Type in the Dominion Museum, Wellington.

Type locality: Cook Strait, off Wellington, on a flat stone entangled on a fishing line of 200 fathoms length. Abundant.

Remarks: J. A. Thomson (1918B) has described this species very fully, and his paper should be consulted for details of the pallial sinuses, and spicules.

Fossil Distribution: L. neozelanica Thomson is not known to occur in Wanganuian or Taranakian strata, but J. A. Thomson has determined single valves of a Liothyrella from the shell-bed at Target Gully (Awamoan) as “Liothyrella cf. neozelanica Thomson.” These were collected by Dr. H. J. Finlay.

Some immature specimens collected by the writer from tufaceous greensands at Whenuataru Peninsula, Pitt Island, Chatham Islands, agree in shape with juvenile specimens of the Recent species. These records should not be accepted without confirmation.

[Footnote] * As interpreted by the Chatham Island material here figured, pl. 1, fig. 2.

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Liothyrella oamarutica (G. Boehm 1904). (Pl. 1, Figs. 5–6).

1904. Terebratula oamarutica Boehm, Zeitschr, d. Deutsch. Geol. Ges., Jahrg., 1904, Monatsber. Nr. 8, p. 149, taf. XV, figs. 6, 7 a-c.

Diagnosis: A Liothyrella of medium size which is broadly ovate (ratio of length to breadth, 1 : ·9), moderately inflated; and in which the beak is obliquely truncated by a large, broadly marginate foramen, the anterior margin of which rarely extends dorsally of the hinge-line.

Dimensions of a topotype: Length, 36mm.; breadth, 33mm.; thickness, 19mm.

Type in the Boehm collection.

Type locality: Everett's Quarry, Kakanui.

Age: Upper Ototaran.

Distribution: This species is very abundant at the type locality, and is recorded by Thomson (in MSS.) from numerous Ototaran localities near Oamaru. Dr. J. Marwick and the writer collected it from calcareous tuffs at Momoe-a-Toa, Chatham Islands. The Chatham Island specimens (Pl. 1, fig. 5) agree very exactly with topo-types.

Liothyrella pulchra J. A. Thomson 1918. (Pl. 2, Figs. 6–8).

1918. Liothyrella pulchra Thomson, in J. Park, N.Z. Geol. Surv. Bull. No. 20, p. 118, not figured.

1927. Liothyrella pulchra Thomson, N.Z. Board Sci. and Art, Man. No. 7, text-fig. 25 on p. 85.

Diagnosis: A broadly ovate Liothyrella like oamarutica, but with a sulciplicate anterior commissure.

Dimensions of holotype: Length, 27mm.; breadth, 24mm.; thickness, 15mm.

Type in the Dominion Museum, Wellington.

Type locality: Calcareous tuffs, Trig. M., near Totara, Oamaru. Abundant.

Age: Lower Ototaran.

Liothyrella circularis n. sp. (Pl. 2, Fig. 3; Pl. 3, Fig. 6).

Diagnosis: A Liothyrella like kakanuiensis but subcircular in shape, and not quite so inflated.

Type locality: Everett's Quarry, Kakanui.

Dimensions of holotype: Length, 11mm.; breadth, 10mm.; thickness, 6mm.

Age: Upper Ototaran.

Remarks: L. circularis n. sp. is no doubt closely related to L. kakanuiensis (Hutt.) from the same locality and horizon, but the difference in shape seems to merit specific recognition even if the series is variable.

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Liothyrella elongata n. sp. (Pl. 2, Fig. 4).

Diagnosis: A Liothyrella like kakanuiensis but of smaller size, and considerably more elongated (ratio of length to breadth 1 : ·65), and less inflated.

Dimensions of holotype: Length, 7mm.; breadth, 4·5mm.; thickness, 3·5mm.

Type locality: Caversham sandstone, Seacliff, near Dunedin.

Distribution: L. elongata n. sp. was collected at the type locality by Mr. G. J. Williams, who also discovered it at the junction of the Caversham sandstone with the underlying greensand at Yellow Bluff, Puketeraki. The writer found it not uncommon in the Caversham sandstone at Karitane.

Liothyrella pittensis n. sp. (Pl. 1, Fig. 1).

Diagnosis: A Liothyrella of the general shape of oamarutica, but with strongly carinate beak-ridges, wide ventral palintropes, a relatively high symphytium, an erect beak, and a large foramen which is narrowly marginate and not oblique.

Dimensions of holotype: Length, 42mm.; breadth, 31mm.; thickness, 23mm.

Type locality: Calcareous tuffs, Flowerpot Harbour, Pitt Island, Chatham Islands.

Liothyrella skinneri n. sp. (Pl. 1, fig. 3).

Diagnosis: A Liothyrella like oamarutica, but more elongate (ratio of length to breadth, 1 : ·75), and with a labiate foramen.

Dimensions of holotype: Length, 40mm.; breadth, 31mm.; thickness, 23mm.

Type locality: Calcareous tuffs, Momoe-a-Toa, Chatham Islands, where it is abundant and is associated with L. gravida (Suess) and L. oamarutica (Boehm).

Remarks: The species is named in honour of Mr. H. D. Skinner, the leader of the Otago Institute Expedition to the Chatham Islands.

Liothyrella thomsoni n. sp. (Pl. 2, fig. 5).

Diagnosis: A broadly elliptical depressed Liothyrella differing from such species as concentrica and oamarutica with which it agrees in size, in the broadly rounded hinge-line and labiate foramen.

Dimensions of holotype: Length, 38mm.; breadth, 30mm.; thickness, 17mm.

Type locality: Uppermost Mount Brown limestone (E), escarpment Weka Pass-Omihi (a single specimen).

Remarks: J. A. Thomson (after whom the species is named) noted that the genus Liothyrella was absent from the Weka Pass-Waipara district (1920, p. 369). This is the first record of its occurrence.

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Distribution: With L. thomsoni I associate temporarily a Liothyrella n. sp. recorded by Thomson (1926, p. 151) from the Hutchinsonian greensands at Deborah. Imperfect specimens of this form in the Department of Geology, Otago University, agree in shape with the type, but are marginate or show only incipient labiation. To this species also I refer at present specimens from Band F, Milburn Quarry, Clarendon. These are usually distorted, and again the foramen is marginate. Further material may prove that more than one species is here included.

The stratigraphical range of the species of Liothyrella so far as it is known is shown in the following table:—

[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]

Waiarekan. Lower Ototaran. Middle Ototaran. Upper Ototaran. Landonensis-horizon Waitakian Basal Hutchinsonian. Hutchinsonian greensands. Uppermost Mount Brown Beds. Awamoan. Taranakian. Wanganuian. Recent.
L. boehmi * * * * *
L. circularis *
L. concentrica Horizon doubtful.
L. elongata ?
L. gravida Horizon doubtful.
L. kakanuiensis ? *
L. landonensis *
L. magna Horizon doubtful.
L. neglecta ?*
L. neozelanica ? *
L. oamarutica * * *
L. pittensis Chatham Islands.
L. pulchra *
L. skinneri Chatham Islands.
L. thomsoni ? *
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Literature Consulted.

Boehm, G., 1904. Ueber Tertiare Brachiopoden von Oamaru, Südinsel Neuseeland. Zeitsch. Deutsch. Geol. Jahrg., 1904, pp. 146–50, taf. XV.

Hamilton, A., 1910. In Webb, E. J. H., N.Z. Geol. Surv. Bull. No. 11, p. 18.

Hutton, F. W., 1873. Catalogue of the Tertiary Mollusca and Echinodermata of New Zealand, in the Collection of the Colonial Museum. Wellington, xvi, 48 pp.

—— 1905. Revision of the Tertiary Brachiopoda of New Zealand. Trans. N.Z. Inst., 37, pp. 474–81, pls. 45–46.

Jackson, J. W., 1918. The New Brachiopod Genus, Liothyrella, of Thomson. Geol. Mag., Dec. 6, vol. 5, pp. 73–79.

Park, J., 1923. On the Discovery of the Liothyrella boehmi Greensand Band at Flume Creek, Waitaki Valley. Trans. N.Z. Inst., 54, pp. 80–2.

Suess, E., 1864. Brachiopoden, in Zittel, K. A. Novara Expedition, Geol. Theil., Bd. I, Abth. II, Palaontologie von Neu-Seeland, pp. 56–7, taf. IX, figs. 5a, b.

Thomson, J. A., 1916. Additions to the Knowledge of the Recent and Tertiary Brachiopoda of New Zealand and Australia. Trans. N.Z. Inst., 48, pp. 41–47, pl. 1.

—— 1918A. Brachiopoda, in J. Park, N.Z. Geol. Surv. Bull. No. 20, pp. 117–19.

—— 1918B. Brachiopoda, Austral. Ant. Exp. 1911–14, Sci. Rept., Ser. C, vol. IV, pt. 3, 75 pp., 4 pls.

—— 1920. The Notocene Geology of the Middle Waipara and Weka Pass District, North Canterbury, New Zealand. Trans. N.Z. Inst., 52, pp. 322–415.

—— 1926. Marine Phosphatic Horizons in the Tertiary Limestones and Green-sands of South Canterbury and North Otago, and Brachiopod Evidence as to their age. N.Z. Journ. Sci. and Techn., 8, pp. 143–60.

—— 1927. Brachiopod Morphology and Genera (Recent and Tertiary). N.Z. Board Sci. and Art, Man. No. 7, 338 pp., 2 pls.

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Fig. 1.—Liothyrella pittensis n. sp. Holotype × 1.3.
Fig. 2.—Liothyrella gravida (Suess) × 1.2 Chatham Islands.
Fig. 3.—Liothyrella skinneri n. sp. Holotype × 1.3.
Fig. 4.—Liothyrella concentrica (Hutton). Leetotype × 1.5.
Fig. 5.—Liothyrella oamarutica (Boehm). Momoe-a-Toa × 1.4.
Fig. 6.—Liothyrella oamarutica (Boehm). Topotype × 1.4.

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Fig. 1.—Liothyrella magna (Hamilton). Lectotype × 85
Fig. 2.—Liothyrella neglecta (Hutton). Lectotype × 3
Fig. 3.—Liothyrella circularis n. sp. Holotype × 3
Fig. 4.—Liothyrella elongata n. sp. Holotype × 4.5
Fig. 5.—Liothyrella thomsoni n. sp. Holotype × 2.
Fig. 6.—Liothyrella pulchra Thomson. Interior of dorsal valve × approx. 1.5. Specimen in Dominion Museum.
Figs. 7–8.—Liothyrella pulchra Thomson. Holotype × 2.

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Fig. 1.—Liothyrella neozelanica Thomson Holotype × 1.5.
Fig. 2.—Liothyrella landonensis Thomson. Holotype × 2.6.
Fig. 3.—Liothyrella kakanuiensis (Hutton). Lectotype × 2.8
Fig. 4.—Liothyrella neozelanica Thomson. Paratype. Interior of dorsal valve × 2.
Fig. 5.—Liothyrella boehmi Thomson. Holotype × 1.5.
Fig. 6.—Liothyrella Liothyrella circularis n. sp. Interior of dorsal valve × 4.8.