Angyomphalus radianodosa n.sp.

PI. 4 figs 4-10

Description. Shell very small low-spired lenticular, with 4Vz whorls, phaneromphalous. Protoconch seemingly simple, smooth, without sharp boundary between protoconch and teleoconch; suture shallow; upper whorl face sloping gently toward the periphery and decorated by narrow radiating nodes which are slightly sigmoidal just below the suture; growth lines extending beyond the nodes, prosocline above the peripheral selenizone, but faint below the selenizone, swinging forward for a short distance and then backward into the umbilicus; columellar lip thin next to the parietal wall but with a thick subtriangular section at the circumumbilical funicle, outer lip thin, sharply angulated at periphery, size of slit and lunulae unknown.

Types. Holotype (F78372) and 6 figures paratypes (F78373 -6). There are 42 unfigured additional specimens (F78377) 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. 25 from Swains Gully (Locality 25), 6 from south-east of 'Rangari' (Locality 18) and 6 from Glenbawn (Locality 31).

Geographic distribution. 'Rangari' to Glenbawn.

Geological age. Middle to late Tournaisian.

Etymology. Derived from the Latin radian meaning radial, and nodosusmeaning nodose; referring to the radial nodes below the sutures.

Remarks. This form differs from the only described Australian species, Angyomphalus depressa Campbell & Engel in that the latter has a low spired shell with more acute periphery and more closely spaced and longer nodes just below the suture. It resembles the Belgian type species Angyomphalus radians (de Koninck, 1881) ill shell character but differs in being much smaller.