Plastiscala morchi
(Angas, 1871)
Description:
Dimensions range from 7 mm - 20 mm high and 2.5 mm - 4 mm wide.
Width to height ratio: 0.36:1 ~ 0.2:1
Shell: awl-shaped, attenuated, narrow; solid; minute to small. Exterior colour fawn, costae dull white. About 11 whorls, convex; body whorl with thin peripheral cord; protoconch with ~2 whorls smooth, bulbous; teleoconch with 6.5-9 whorls with rough ribs on the first several whorls. Spire strongly convex. Suture impressed. Imperforate: umbilicus closed. Approximately 25 costae on the body whorl. Costae are prosocline, low, rounded. There is a single varix on each whorl. The varix is rather thick, a little wider at the suture. Intercostal spaces surface sculptured with rough spiral cords which cross the costae. Interstices with approximately 10 spiral striae per whorl. Base weak threads and basal cord. Base with 12 - 15 spiral striae, Columella small, oblique. Aperture ovate, lip thickened by varix externally.
Compared with P. magna, this species is more elongate, has more rounded whorls with stronger sculpture, and has stronger varices which are more regularly spaced. P. magna has no basal rib, but there is a weak rib in P. morchi., Iredale, 1936, described two subspecies:, Plastiscala morchi bentha Iredale, 1936 a larger, more slender shell with more rounded whorls the longitudinals are more sharply cut and the spiral cords are finer and more distinct., , Plastiscala morchi profundior Iredale, 1936 the sculpture is much weaker, the longitudinal ribs notably so, while the concentric cording is also much less defined and the varices more flattened.
Distribution:
Port Jackson, NSW
Habitat:
99-457 m [Iredale, 1936:302]
Type Material:
Holotype: NHMUK 1870.7.5.10 for Plastiscala morchi (Angas, 1871) - Type Locality: dredged near the 'Sow and Pigs', Port Jackson, New South Wales.. [Brown, L. & Neville, B.D., 2015]
Iredale, T. (1936). Plate xxii. Fig. 21.
Distribution
as listed in source literature
Angas, G.F. (1871).
Plate 1. Fig. 7.
pp: 15.
original description
Sowerby, G. B. II. (1873).
Plate x. Fig. 76.
Sowerby, G. B. II. (1873).
Plate xiv. Fig. 123.
Tryon, G.W. (1887).
Shown in text as Scala morchi Angas, 1871
Plate 16. Fig. 7.
pp: 82.
Tryon, G.W. (1887).
Shown in text as Scalaria (Psychrosoma) erronea Tapparone Canefri, 1876
Plate 16. Fig. 7.
pp: 79.
Clessin, S. (1897).
Shown in text as Scalariamorchi Angas, 1871
Plate 5. Fig. 9.
pp: 21.
Shell small, whitish, narrow, densely striated spirally; whorls numerous, increasing slowly; varices very close-set, somewhat thickened, slightly expanded at the suture.
Verco, J.C. (1906).
Shown in text as Scala morchi, Angas.
pp: 148.
pp: 147.
Cotton, B.C. & Godfrey, F.K. (1931).
pp: 7.
Iredale, T. (1936).
Shown in text as Scala morchi Angas.
Plate xxii. Fig. 21.
pp: 302. Plate xxii.
Iredale, T. (1936).
Shown in text as Plastiscala morchi profundior Iredale, 1936
Plate xxii. Fig. 22.
pp: 303.
Iredale, T. (1936).
Shown in text as Plastiscala morchi bentha Iredale, 1936
Plate xxii. Fig. 23.
pp: 303.
Macpherson, J.H. & Gabriel, C.J. (1962).
pp: 115.
Kaicher, S.D. (1980).
Australian Museum C.60657
Nakayama, T. (2003).
pp: 109. Plate 3. Fig. 8.
Plastiscala morchi (Angas, 1871)
height 10.0 mm; breadth 4.0 mm (WMNH-Mo-Na693)
Beechey, D. (2008).
pp: Plastiscala morchi. Fig. 1.
Off Lakes Entrance, Victoria, 27-37 m (C.461137)
pp: Plastiscala morchi. Fig. 2.
Holotype: of Plastiscala morchi bentha. 3.5-4 miles off Wattamolla, NSW, 99-108 m (C.016342)
pp: Plastiscala morchi. Fig. 3.
Holotype: of Plastiscala morchi profundior 23 miles east of South Head, Sydney, 457 m (C.024420)
Huang, C. W. & Lee, Y.C. (2016).
