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Volume 56, 1926
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Descriptions of Six New Species and a New Genus of Gasteropod Mollusca from Northern New Zealand.

[Read before the Auckland Institute, 25th November, 1924; received by Editor, 22nd December, 1924; issued separately, 5th May, 1926.]

Plates 103,104.

With the exception of the large and handsome Calliostoma, the species described in the following paper are of small size. For two remarkable Rissoids it has been found necessary to propose a new genus. Another genus and a subgenus new to the New Zealand fauna are also represented.

The writer is indebted to Mr. R. A. Falla and Mr. W. La Roche for samples of shell-sand and dredgings, and to Mr. H. J. Finlay for permission to describe a species he also had separated out as new.

Genus Calliostoma Swainson, Shells and Shell-fish, 1840. p. 351.

Type: Trochus zizyphinus L.

Considerable variation in the sculpture of the common Calliostoma punctulatum is noticeable when large series are examined. The number of the ribs remains fairly constant, but their relative strengths vary. The majority of specimens collected from kelp and clean rocks have 7 prominent primary ribs, the remaining 5 forming interstital riblets of varied size. Specimens from muddy localities, however, are much paler in colour, and more finely and uniformly sculptured, due to the primary ribs becoming smaller, and the interstital riblets larger until they almost equal the former in strength.

Calliostoma punctulatum appears to be the direct ancestor of the new species described below.

Calliostoma osbornei n. sp. (Plate 103, figs. 1, 2.)

Shell acutely conical, solid, imperforate. Outlines straight. Whorls 10 ½, body-whorl angled at periphery. Protoconch of 1 ½ smooth and globular whorls. Second and third post-nuclear whorls with 3 spiral ridges. A fourth spiral ridge develops at suture of fourth post-nuclear whorl, and during the next few whorls 2 more spirals are gained, with a maximum of 6 at the penultimate whorl. All spiral ridges conspicuously beaded. Interstitial riblets, when present, very faintly indicated; absent in most specimens. Base convex, with 10–11 spiral granular ridges. Axial sculpture consisting only of dense oblique growth-lines. Colour chestnut-brown, ridges dark brown with the granules cream or whitish. Suture not deep. Spire high, almost twice the height of aperture. Aperture rhomboidal, nacreous, and lirate within. Outer lip thin. Basal lip thickened with a nacreous callus. Inner lip spreading over parietal wall as a thin transparent nacreous glaze. Columella oblique, arcuate, with a slight tubercle at base. Operculum horny, multispiral with central nucleus as in punctulatum but more closely coiled.

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Diameter, 34 mm.; height, 27.5 mm. Diameter, 33 mm.; height, 26 mm. (holotype). Diameter, 31 mm.; height, 25 mm. Diameter, 28.5 mm.; height, 24 mm.

Holotype and three paratypes in author's collection, Auckland. A number of specimens in possession of residents of Great Barrier Island.

Habitat.—Off Cape Barrier, Great Barrier Island, in about 27 fathoms; some from the stomach of the common snapper, Pagrosomus auratus (Forster). Named in honour of Mr. C. Osborne, of Tryphena, who has collected the species on numerous occasions.

This species is quite constant, and is easily distinguished from punctulatum by the straight outlines, much taller spire, greater number of whorls, and different sculpture consisting of fewer primary ribs and with the interstitial riblets absent or only faintly indicated. (See Plate 103.)

Genus Liotina Fischer, Man. de Conch., 1885, p. 831.

Type: L. gervillei Defrance.

Liotina tryphenensis n. sp. (Text-figs. 4—6.)

Shell small, almost flat above, rounded below and widely umbilicate. Whorls 3 ½, very rapidly increasing. Protoconch smooth, of 1 whorl. Post-nuclear whorls sculptured throughout with strong close and radiating striae. Body-whorl tricarinate. Two rounded spiral keels, one above and the other below periphery, are connected with heavy axial varices, nodulous where they join spiral keels. These varices are absent from greater part of dorsal area of body-whorl, but are again resumed just behind aperture. A third rounded spiral keel at periphery is noticeable where body-whorl is devoid of axial varices. Where crossed by these varices central keel is almost suppressed, and appears only as a convex space between upper and lower keels. Ten varices on body-whorl, two of which are behind aperture. A series of irregular axial basal ribs project as teeth into umbilicus. Suture impressed. Aperture circular with a smooth continuous inner margin, strengthened by an interrupted heavy concentrically-striated outer lip, which terminates as a projection towards umbilicus. Umbilicus perspective, deep and wide. Operculum horny, concave, multi-spiral, with a central nucleus in the form of a small pit. Colour uniformly light brown.

Diameter—major, 3.2 mm.; minor, 2.5 mm. Height, 1.5 mm.

Holotype and one paratype in author's collection, Auckland.

Habitat.—Tryphena, Great Barrier Island, on under-side of stone at low water (coll. A. W, B. P., January, 1924).

It was suggested to the writer by Mr. H. J. Finlay that possibly this species was identical with Suter's Liotia serrata. Iredale considered both Liotia solitaria and L. serrata of Suter juveniles of the genus Angaria (1). The first-mentioned species Miss Mestayer has proved to be the juvenile of Astraea heliotropium (Martyn) (2). With regard to L. serrata, one of Suter's figures (3) is undoubtedly that of an adult shell, having a variced mouth and other characters typical of Liotina.

Both Mr. Finlay and the writer are of the opinion that cerrata is here correctly placed, and that Iredale was wrong in classing it as the juvenile of Angaria.

As Suter's figure of serrata is a poor one, and his description rather meagre, the differentiating characters between tryphenensis and serrata are given below.

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1. Calliosloma osbornei n. sp. (paratype).
2 Calliostoma osbornei n. sp. (holotype).
3. Calliostoma punctulatum Martyn, Titirangi, Manukau Harbour (muddy locality).
4 Calliostoma punctulatum Martyn, Reotahi, Whangarei Heads (on kelp).
5. Calliostoma punctulatum Martyn, Tryphena, Creat Barrier Island (on seaweed).

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Turbonilla finlayi n. sp.

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The interrupted axial sculpture of tryphenensis is quite a distinctive feature. The holotype, measuring 3.2 × 2.5 × 1.5 mm., has 25 nodulous projections on the spire and body-whorls, 2 of which are just behind aperture. Major diameter of shell at commencement of denuded portion of body-whorl is 2 mm. The paratype, 2.9 × 2.1 × 1.25 mm., has 23 of the nodulous projections, 2 of which are behind aperture, as in holotype. Major diameter at commencement of denuded portion of body-whorl is 1.5 mm. This shows that the interrupted sculpture is a permanent feature, the denuded portion occupying the same relative area and position in specimens of different size.

In L. serrata the projections or denticles are confined to periphery of the flat whorls above, and are neither interrupted nor are they connected as in tryphenensis by axial varices with the lower carina. Also, tryphenensis is distinctly tricarinate, while serrata has only one rounded carina below and a sharp angle at periphery above, from which the denticles project.

Miss Mestayer's Liotia suteri (4) would also be better placed in Liotina.

Genus Promerelina n. gen.

Type: Promerelina crosseaformis Powell.

A Rissoid genus evolved from Merelina (5), having a differently sculptured protoconch, and remarkable basal characters superficially resembling Crossea. The three basal spirals of Merelina have in this genus resolved into a single strong basal plate arising from suture, just behind aperture, and terminating at base of peristome. The columella also differs from Merelina in being free and projecting below. The protoconch, spirally striate in Merelina, is in this genus sculptured with granular spiral ridges. The sculpture of the post-nuclear whorls, clathrate in Merelina, differ also, due to the axial ribs becoming obsolete, leaving the spiral sculpture as prominent keels. In the genotype sufficient of the axial ribs remain to render the spiral keels nodulous at the points of intersection, but in P. coronata, the second species of the genus, the axial sculpture is entirely wanting. Protoconch and basal characters identical in both species, which differ so much from typical Merelina and all other known Rissoids that the author feels quite justified in proposing a new genus for these unique shells.

Promerelina crosseaformis n. sp. (Text-fig. 2.)

Shell very small, clathrate. Whorls 5 ½. Protoconch of 1 ½ convex whorls, sculptured with 10 granular spiral ridges. Succeeding whorls with 2 strong spiral ridges crossed by faint regularly-spaced axial ribs produced into nodules at points of intersection. A third smooth strong spiral ridge arises from suture just behind aperture and terminates at base of peristome. Columella vertical, with an indistinct fold above (which is more apparent in the larger decollated Whangaroa specimen), free and projecting below. Suture deep. Aperture oblique-oval. Peristome continuous, double on the outer edge from suture to base of columella, and produced at termination of the three spiral ridges.

Height, 3 mm.; diameter, 1.25 mm.

Holotype in author's collection, Auckland.

Habitat.—Maro Tiri (Chicken Island), (type), in shell-sand (coll, R. A. Falla, December, 1923); Whangaroa—one specimen (coll. W. La Roche, February, 1924).

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Promerelina coronata n. sp.

Shell very small. Whorls 5 ½. Protoconch of 1 ½ convex whorls, sculptured with 10 spiral granular ridges. Succeeding whorls abruptly angled at periphery and produced into a smooth lobed lamellar ridge with an upward tilt. Whorls smooth above but spirally striate below ridge. A deep spiral groove at periphery separates ridge from sculptured lower portion of whorls. Suture deep. Colour pale buff. Columella subvertical with an indistinct fold, free and projecting below. Aperture and basal characters similar to those of the foregoing species. A single strong spiral basal plate arises from suture just behind aperture and terminates at base of peristome. Outer lip thickened and produced at termination of spiral ridge and basal plate.

Height, 3 mm.; diameter, 1.5 mm.

Holotype in author's collection, Auckland.

Habitat.—Maro Tiri (Chicken Island), (type), in shell-sand (coll. R. A. Falla, December, 1923): Rangaunu Bay, in 12 fathoms (two imperfect specimens from dredgings by Mr. W. La Roche, May, 1924).

Genus Turbonilla Risso, subgenus Turbonilla s. str., Hist. Nat. Eur. Mer., vol. 4, 1826, p. 224.

Type: Turbonilla typica Dall and Bartsch = T. plicata Risso, 1826, Bull. 68, U.S. Nat. Mus.; Dall and Bartsch, West American Pyramidellid Mollusks, p. 29.

Turbonilla finlayi n. sp. (Plate 104.)

Shell small, elongate-conical. Colour dull-white; fresh specimens semitransparent, with a narrow opaque band immediately below suture, caused by base of preceding whorl showing through, giving the appearance of a margining of suture. Sculpture consisting of numerous close straight and flattish axial riblets with much narrower interstices; those on upper whorls almost linear. Axial ribs continue right to base of body-whorl but become indistinct and mostly bifurcate after passing periphery. Interstices above periphery lightly channelled, grooves terminating abruptly at periphery. Axial ribs on body-whorl varying from 42 to 46; the holotype has 44. Whorls 7, plus a sinistral convoluted heterostrophe protoconch of 2 smooth whorls, with a lateral nucleus. Spire high, about 2 ¼ times height of aperture. Suture deep. Outlines of whorls very little convex, and slightly shouldered immediately below suture. Aperture oblique, elongately oval, angled above and rounded below. Peristome discontinuous, thin and sharp, terminating in a thin callosity, spreading broadly over parietal wall. Columella arcuate.

Dimensions: 5.2 × 1.75 mm. (holotype); 5.0 × 1.62 mm.; 4.87 × 1.5 mm.; 4.80 × 1.45 mm.; 4.5 × 1.4 mm.

Holotype and several paratypes in author's collection, Auckland.

Eight adult and two juvenile specimens from Rangaunu Bay and Awanui Heads collected by Mr. W. La Roche; two decollated specimens from Stewart Island, lent by Mr. H. J. Finlay.

Habitat.—Awanui Heads (type), washed up on beach; Rangaunu Bay, in 12–15 fathoms; Stewart Island.

Dall remarks that usually in Turbonilla s. str. both ribs and intercostal spaces are less strongly defined on the base below the periphery than on the

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Fig. 1.—Promerelina coronata n. sp.
Fig. 2.—Promerelina crosseaformis n. sp.
Fig. 3.—Terenanax pagoda n. sp.
Fig. 4, 5, 6.—Liolina tryphenensis n. sp.

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exposed portion of the whorls above it. No doubt this is caused by light channelling of the intercostal spaces above the periphery, as in T. finlayi.

Of the four Recent species of Turbonilla found in New Zealand, T. finlayi is the first of the typical section. T. zelandica Hutton has the axial ribs stopped at the periphery, with the base smooth. Thus zelandica really belongs to the subgenus Chemnitzia, as Hutton originally placed it, and not to the typical section as classed by Suter. A second species of Chemnitzia—T. lamyi Hedley (6)—has been described from Macquarie Island. The fourth Recent Turbonilla—T. (Pyrgolampros) blanda Finlay (7)—represents still another subgenus.

Genus Teretianax Iredale, Proc. Mal. Soc., vol. 13, pts. 1, 2, August, 1918, p. 39.

Type: Scalenostoma suteri Oliver, Trans. N.Z. Inst., vol. 47, 1915, p. 533, pl. 11, fig. 30.

Teretianax pagoda n. sp.

Shell small, white, surface smooth, sides straight with a single prominent spiral keel. Whorls 7. Protoconch bluntly rounded, smooth, of 1 whorl. The following whorl with 2 spiral ribs, the lower one the more prominent. On the succeeding whorls the upper rib rapidly diminishes, forming only a faint margining of suture, and finally disappears, while the lower rib gains in strength, forming a prominent heavy spiral keel. Suture impressed. Aperture oblique, narrowly rounded below and angled above, with an indentation above shoulder. Peristome continuous over parietal whorl as a thickened callosity.

Height, 2.5 mm.; breadth, 0.9 mm. (holotype).

Holotype and three paratypes in author's collection, Auckland.

Habitat.—Tryphena, Great Barrier Island (type), in shell-sand (coll. A. W. B. P., January, 1924); Maro Tiri (Chicken Island), in shell-sand (coll. R. A. Falla, December, 1923); Rangaunu Bay, in 12 fathoms (three specimens from dredgings by Mr. W. La Roche, May, 1924); Mongonui Heads (four specimens from dredgings by Mr. W. La Roche, June, 1924).

This makes the second known species, and also adds a genus to our fauna. The genotype is from Sunday Island, Kermadec Islands.

The genotype of Scalenostoma Deshayes, S. carinatum Deshayes, from the Isle of Bourbon, figured in Structural and Systematic Conchology, Tryon, 1883, vol. 2, pl. 68, fig. 95, shows that that genus has a small protoconch and that the peristome is retracted towards the suture.

Both species of Teretianax have a comparatively large rounded nucleus, and peristome is only slightly indented above shoulder. Iredale considers Teretianax a doubtful member of the Eulimidae (8).

References.

1. T. Iredale, Trans. N.Z. Inst., vol. 47, p. 439, 1915.

2. M. K. Mestayer, Trans. N.Z. Inst., vol. 50, pp. 191–92, 1918.

3. H. Stter, Proc. Mal. Soc., vol. 8, p. 23, pl. 2, figs. 4, 5, 1908.

4. M. K. Mestayer, Trans. N.Z. Inst., vol. 51, p. 130, pl. 8, figs 1–3. 1919.

5. T. Iredale, Trans. N.Z. Inst., vol. 47, p. 449, 1915.

6. C. Hedley, Moll. Australian Ant. Exp. (1011–14), p. 62, pl. 9, fig. 100, 1916.

7. H. J. Finlay, Trans. N.Z. Inst., vol. 55, p. 522, fig, 4, 1924.

8. T. Iredale, Proc. Mal. Soc., vol. 13, pts. 1, 2, p. 39, 1918.