Conus sp.

Conus sp.

DESCRIPTION.

Shell of medium size for genus, up to 27 mm high. Protoconch of 2½ smooth, turbiniform whorls, coiled in axis of shell and protruding above teleoconch whorls. Teleoconch of five to six whorls, biconic with very low spire. Sculpture present on whorl shoulder of about five thin, equally spaced spiral threads, much narrower than interspaces. Last whorl anterior to shoulder smooth, except for 5–10 weak lirae at the anterior of the whorl ⁽¹⁾.

MATERIAL EXAMINED ⁽¹⁾.

Australia: Western Australia: Walpole, 24 km north of Walpole townsite on west side of Thomson Road, Deep River 743 486: 28 specimens (WAM 67.179, 69.187, 99.204, 04.175, 10.06–7, 15.282–3; NMV P316331–3).

Cape Le Grand National Park, old track surface, 3.7 km south-east of Frenchman Peak: 1 specimen (WAM 80.1354).

Total 29 specimens.

REMARKS

An internal mould of a possible species of Conus was recorded by Darragh and Kendrick (2008) from the late Eocene sandstone at Kalbarri, Western Australia.

No species of Conus are known from the Eocene formations of the St. Vincent or Otway basins.

Figure F1. A. Map showing the modern circulation around southern Australia and location of Cenozoic basins. 1 = Bremer Basin, 2 = Eucla Basin, 3 = St. Vincent Basin, 4 = Murray Basin, 5 = Otway Basin, 6 = Bass Basin, 7 = Gippsland Basin.

The earliest occurrence of the genus in eastern Australia is in the Late Oligocene Jan Juc Formation. The preservation of the specimens varies somewhat and the better preserved material is slightly distorted. Most of the specimens are fragments ⁽¹⁾.

This species bears some resemblance to the Victorian Miocene species Conus pullulescens Tenison Woods, 1879 in respect to the protoconch, but lacks the spiral sculpture covering the last whorl in that species ⁽¹⁾.

It has a general resemblance to the low-spired forms of C. sauridens Conrad, 1833, Eocene, United States of America. A laterally compressed internal mould (WAM 84.1027) from the Pallinup Formation at Mt Barker, Plantaganet loc 6129, west side Barrow Rd, may possibly be this species. It has four lirae on the shoulder. Indeterminate internal moulds of Conus have been found in the Nannarup Limestone quarry (WAM 69.250) and at Bremer Bay (G6053) (but possibly actually from Balladonia). Both the latter specimens do not bear any resemblance to the Walpole material ⁽¹⁾.

OCCURRENCE

Eucla Basin: Pallinup Formation (From Lutetian to Late Eocene)

The Pallinup Formation was dated as late Eocene, Priabonian, by McGowran (2009), and is coeval with the Blanche Point Formation of South Australia and the Browns Creek Formation of Victoria ⁽¹⁾.

It is my opinion that these two specimens can be closely correlated with Conus convexus (Harris, 1897): in Conus convexus, the body-whorl has an elevated band at its periphery, which is rugosely lineated; its whole surface is covered by small, undulating, irregular sulci, which broaden anteriorly, while in these two specimens, last whorl anterior to shoulder is smooth, except for 5–10 weak lirae at the anterior of the whorl. Both in Conus convexus and in these two specimens, the whorls of the spire are ornamented by five or six spiral threads and, above all, the form of the protoconch is identical.