Eotomaria umbilicata, Yoo, 1994

Yoo, E. K., 1994, Early Carboniferous Gastropoda from the Tamworth Belt, New South Wales, Australia, Records of the Australian Museum 46 (1), pp. 63-120 : 75-76

Eotomaria umbilicata n.sp.

PI. 5 figs 1-3

Description. Shell of about 4 whorls, very small, low spired, rotelliform, and widely phaneromphalous. Protoconch simple, first 1Vz whorls smooth, the remainder with faint reticulate ornament, with spiral and collabral cords appearing on the third whorl. Teleoconch with whorls increasing in size rapidly; whorl profile inflated with area above selenizone rather flat; sutures moderately deep; ornamentation of strong regularly spared collabral cords with lighter spiral threads, collabral cords orthocline below suture, but curved backward towards upper margin of selenizone; cords more finely spaced below selenizone with strong sinus extended to the base. Selenizone wide, bordered by raised spiral thread; lower margin of selenizone on whorl periphery slightly concave, ornamented with curved lunulae. Aperture simple, inner lip thin, arcuate; outer lip with a deep sinus culminating in a moderately deep slit above periphery.

Types. Holotype ( F78379 ) and 2 figured paratypes ( F78380 ). There are 42 unfigured additional specimens (F7838l) from the type locality.

Type locality. 150 m west of 'Marohn', homestead, on the Scone-Gundy roadside, 4 km south-west of Gundy, NSW (Locality 28).

Stratigraphic position. In bioclastic limestone, upper part of the Dangarfield Formation.

Additional material. 12 specimens from various horizons of the Dangarfield Formation , east of Glenbawn Dam (Localities 29-31) .

Geographic distribution. Glenbawn area.

Geological age. Late Tournaisian.

Etymology. Referring to umbilicus.

Remarks. This species is characterised by a low spired shell with strong sinuous collabral cords and an exceptionally wide umbilicus. This form resembles the type species Eotomaria canalifera Ulrich in Ulrich & Scofield from Tennessee, in having a coeloconoidal, sublenticular shell with deep sinus and selenizone above the periphery, but differs from in having round whorl profile and round aperture. This is different from any known species of the Australian euomphaloideans.