2 
T.A. Darragh 
C. gigas and C. platypyga to the subgenus Erosaria, which he 
regarded as a senior synonym of Aricia. In 1912, Chapman 
described Cypraea gabrieli, regarded here as a synonym of Z. 
gigas. 
Schilder (1927) erected Gigantocypraea as a subgenus of 
Umbilia with C. gigas McCoy as the type species. He also 
placed the other species mentioned by Tate in Umbilia. 
However, in 1930, Schilder raised Gigantocypraea to generic 
status and referred the other species to Zoila, but subsequently 
(Schilder, 1935) reduced Gigantocypaea to a subgenus of 
Zoila and added anew subspecies, Z. (Z.)platypyga simplicior, 
regarded here as a synonym of Z.platypyga. 
Time range and distribution 
Living species of Zoila are known only from the southern and 
western coasts of Australia. There are seven recognised 
species, with distribution ranging from Apollo Bay in Victoria 
westwards across the southern coast and up the west coast of 
Western Australia as far north as the West Kimberley district 
(Wilson and Clarkson, 2004). Fossil species of Zoila are more 
widespread. The earliest known species, recognised by this 
author, occurred in the Paleocene to early Eocene of the 
Chatham Islands, New Zealand. This species may have given 
rise to younger Australian species. The earliest Australian 
species Z. viathomsoniae sp. nov., recorded from the upper 
Eocene of southwest Western Australia, is probably an 
ancestor of the younger Australian species of Zoila, of which 
there are two groups: an eastern and a western group. The 
eastern group is known from southeast Australia, and ranged 
in age from late Oligocene to middle Miocene. This group is 
characterised by having prominently developed anterior and 
posterior canals and does not seem to be ancestral to any 
living species. The western group is known from Victoria, 
Western Australia, Indonesia and India, and ranged in age 
from middle Miocene to Recent. 
The oldest known member of the western group occurred 
in the middle Miocene of Western Australia. It seems to be 
ancestral to Z. campestris sp. nov. from the Pliocene of 
Western Australia. This species is probably ancestral to some 
of the living species, in particular Z. venusta (Sowerby, 1846). 
Species somewhat similar to the Western Australian species 
are found in the Neogene of Indonesia and India. A single 
species, known from one fragmentary specimen, occurred in 
the late Miocene of Victoria. 
Affinities 
Generic distinction among cowries is subject to much controversy. 
Few features of the shell can be used to characterise species 
groups, particularly without knowing their anatomy and 
molecular biology. Even when this information is available, it is 
not always possible to apply this knowledge to include 
unequivocally fossil species in groups composed of living 
species. The fossula is one shell structure that does seem to vary 
sufficiently to be able to use it to some extent in supraspecific 
classification, and link fossil and living species. 
The Australian fossil cowries treated here have a type of 
fossular morphology similar to that found in species assigned to 
four nominal genera: Cypraeorbis Conrad, 1865; Bernaya 
Jousseaume, 1884; Zoila Jousseaume, 1884; and Barycypraea 
Schilder, 1927. Of these four, only Zoila is based on a living 
species, and hence can be characterised on the basis of anatomy 
and genetics, although Barycypraea — based on a fossil species 
— has living representatives. The close morphological 
relationship between the first three genera was first recognised by 
Schilder (1926), who placed Zoila as a subgenus of Cypraeorbis 
and synonomised Bernaya with Cypraeorbis. Later, as his 
subdivisions of the Cypraeidae became smaller, and more genera 
were recognised on the basis of minor differences, Schilder 
(1941) placed the three genera in his subfamily Cypraeorbinae, 
with Zoila and Bernaya in the Tribe Bemayini, and Cypaeorbis 
in the Tribe Cypraeorbini. Pol in (1991) regarded Zoila as a 
possible subgenus of Cypraeorbis in the subfamily Bemayinae. 
In the present study, specimens of the type species of each of 
these genera, as well as some other species assigned to them, 
have been examined to determine possible affinities. 
Cypraeorbis, type species Cypraea sphaeroides Conrad, 
1848, was based on a species occurring in the lower Oligocene of 
the southwest United States of America. The genus ranges in age 
from late Eocene to at least early Miocene. The fossula (fig. IB) 
of a C. sphaeroides specimen from Byram, Mississippi (USNM 
498351) is deeply excavated and bounded by a prominent lateral 
ridge on the anterior side. Posterior to this lateral ridge is a slight 
notch in the fossula margin. The lateral ridge merges anteriorly 
with a very weak terminal ridge. Between the first columellar 
tooth and the terminal ridge there is a wide depression, which 
extends as a sulcus parallel with the terminal ridge into the 
fossula. The fossula (figs 1C,3E-F) of a Cypraeorbis ventripotens 
(Cossmann, 1903) specimen — a species closely related to, if not 
synonymous with C. sphaeroides (MacNeil and Dockery, 1984) 
— from the upper Eocene, Town Creek, Jackson, Mississippi 
(Mississippi Geological Survey collection) is large, 
subrectangular, concave, with a prominent notch at the anterior 
end of the thickened interior edge. The terminal ridge, like that of 
C. sphaeroides, is weakly developed and runs into the interior of 
the aperture forming the anterior edge of the fossula as a 
prominent ridge. A well developed groove or sulcus between the 
first columellar tooth and the terminal ridge runs parallel to the 
terminal ridge into the fossula. Specimens of Cypraea willcoxi 
(Dali, 1890) and Zoila arlettae Dolin, 1991 from the Early 
Miocene Chipola Formation of Farley Creek, Florida (MNHN, 
Paris) were also examined. Z. arlettae Dolin has a fossula (fig. 
3N) very similar to C. sphaeroides and C. ventripotens, though 
larger and with a broader notch. Cypraea wilcoxi Dali is very 
close in morphology to Z. arletti and also has a fossula (fig. 30) 
similar in structure to Cypraeorbis sphaeroides and C. 
ventripotens, hence both Cypraea arlettae and Zoila wilcoxi 
seem to be better placed in Cypraeorbis rather than in Zoila as 
suggested by Dolin (1991). 
Petuch (2004) erected two new genera in the subfamily 
Cypraeorbinae, Floradusta (type species Cypraea heilprini Dali, 
1890, early Miocene, Florida) and Loxacypraea (type species 
Cypreaea chilona Dali, 1900, early Miocene, Florida). He 
included in these genera several species that had been included 
by Dolin (1991) in Cypraeorbis, Zoila, Siphocypraea and 
Erronea (Adusta). Petuch stated that a fossula was absent in 
