Zoila mulderi ( Tate, 1892 )

Darragh, Thomas A., 2011, A revision of the Australian fossil species of Zoila (Gastropoda: Cypraeidae), Memoirs of Museum Victoria 68, pp. 1-28 : 14

Zoila mulderi ( Tate, 1892)

Figures 9A–B , 10A–F

Cypraea mulderi Tate, 1892 , pl. 9, fig. 2.— Tate, 1893, p. 316 (description).

Gistortia (Palliocypraea) mulderi (Tate) .— Vredenburg, 1927, p. 60.

Zoila (Zoila) mulderi (Tate) .— Schilder, 1935, p. 337.

Zoila (Gigantocypraea) mulderi (Tate) .— Wilson and Clarkson, 2004:52, pl. 56.

Description. Shell solid, of medium to large size for genus, subglobose, covered with glaze. Spire scarcely visible, covered with thick callus. Posterior canal wide, sides rounded, deeply notched dorsally, sides extended posteriorly into prominent thick flanges extending from base. Anterior canal deeply incised, sides rounded, reflexed dorsally, supported by very thick lateral flanges extending from base. Aperture somewhat sinuous, narrow; outer lip with 24–32 teeth, markedly decreasing in strength at posterior two-thirds. Columella with 9–29 weak, short teeth, present on anterior two-thirds. Fossula weakly depressed, subcircular, bounded anteriorly by weak terminal ridge. Dorsum coarsely dimpled on some specimens.

Dimensions.

Type locality. ‘In a well sinking at Belmont’. A note by Mulder, dated 1891, with a photograph of the specimen sent to Professor Tate (i.e. the holotype), states that only two specimens were known, one in Mulder’s possession (i.e. P13374) and the other sent to Tate. They were ‘taken from the bottom of a shaft about 60 feet below the surface. The shaft was sunk at Belmont near Geelong’. The shaft was sunk in about 1891 in an effort to find fire clay in a paddock close to the junction of the Colac Road (now Princess Highway) and the Germantown (now Grovedale) Road (now Corio Street), probably in allotment 9, Parish of Barrabool. The site was described by Mulder (1897, p. 23).

Type material. Holotype SAM T822 , R. Tate collection.

Figured specimen P13374, collected J.F. Mulder 1891, purchased 1921; figured specimen P3044471, collected F.A. Cudmore, 21 April 1940.

Time range. Longfordian–Batesfordian, Early Miocene.

Occurrence and material. Longfordian. Fishing Point Marl: PL 3035 southeast of Fischers Point (P308770, one fragment).

Batesfordian. Fyansford Formation: PL3040 Belmont Shaft (P13374, one specimen). Curlewis (P304416, P304447, P308743, four specimens and three fragments) .

Gellibrand Formation: PL3048 Bornong Road cutting (P304421-2, P308767, one specimen and two fragments); PL3163 Williams Road cutting (P310103, one fragment of anterior) .

Horizon unknown. Fishing Point Marl? ‘ Cape Otway’ (probably Aire River ) (P302701, one specimen) .

Fishing Point Marl: Fishing Point (P308769, one fragment).

Remarks. The Bornong cutting specimens have the general shape of specimens from Belmont and Curlewis, but have some characters intermediate with Zoila platypyga (McCoy) in that the teeth are more strongly developed. The labral teeth extend along the entire lip and the columellar teeth are strongly developed ridges extending along the entire columella as in Z. platypyga . This suggests that Z. mulderi is ancestral to Z. platypyga . The specimen labelled Cape Otway probably came from the upper part of the Fishing Point Marl (Batesfordian) outcropping in the cliffs along the Aire River at Horden Vale.

Figures

Figure 9. A–B, Zoila mulderi holotype, SAM T822, Belmont, × 1; C–E, Z. dolichorhyncha, paratype, P304417, PL 3028, × 1.

Figure 10. A–F, Zoila mulderi; A–C, E, P13374, Belmont, × 1; D, F, P304416, Curlewis, × 1.

Dimensions.