VOL.37 NO.1 APRIL 2007 - British Shell Collectors' Club

PALLIDULA Page 14
ABOUT ERRONEA SUCCINCTA, A SYNONYM OF E. ONYX
by E.L. Heiman*
Cypraea succincta Linnaeus, 1758 was first described in the 10 th edition of “Systema naturae” together with
Cypraea onyx Linnaeus 1758, a well known cowry species with beautiful brightly colored shells. Later another
onyx-like species were described: Cypraea adusta Lamarck, 1810 and Cypraea nymphae Jay, 1850, but the
famous conchological authors of the past – L.A. Reeve, the Sowerbys, J.C. Melvill, J.G. Hidalgo – treated them
and C. succincta as forms (synonyms) of C. onyx.
Dodge (1953:87), who analyzed Linnaeus’ types, wrote: “C. succincta is not a good species, being merely the
young of onyx. The identity of succincta is, moreover, proved by an examination of the type in the Queens’s
collection in Sweden, as the shell described in the “Museum Ulricae” is manifestly the same as that of the
“Systema.” It is an individual of onyx in the so-called Bulla stage, showing the pale brown background, the two
white bands encircling it, the juvenile teeth appearing only at the base of the columellar lip, and the marked
expansion of the aperture at that point. Hanley (1855, p. 189) had already reached this conclusion. The
conchological writers up to Hanley’s day were either ignorant of the identity of succincta or, if they expressed an
opinion, they were not in agreement.”
Sowerby (1870) pictured three variety of Cypraea onyx (Linnaeus, 1758) – C. onyx, C. adusta Lamarck,
C. nymphae Duclos – and wrote: “For some time I have tried to establish a collateral distinction, by which the
pale fawn variety of onyx might be separated from the two normal conditions. The slopes of the back towards
the ends appeared to be more gradual, the ends thicker, and the umbilicus less distinct; but an examination of
intermediate forms in Miss Saul’s collection, subsequently convinced me that the three varieties must remain
united under one specific name. I have described the dark brown shell as the type, because probably the
normal condition.”
1. Shells of C. onyx pictured in a work by Sowerby (1870)
First row: C. onyx (left) and C. succincta (right)
Second row: C. adusta and C. nymphae (in the middle)
C. onyx, distributed from the African coasts in the Indian Ocean to the Philippines, Japan and Melanesia, was
traditionally treated as a valid species with forms ‘adusta’ and ‘nymphae.’ When studying intraspecific variation
in Cypraeidae the Schilders (1938) first described in the Prodrome six subspecies of onyx in the genus Erronea:
E. onyx onyx the nominotypical subspecies from North Malaysia to Japan, N. Australia, S. Java and Singapore.
E. onyx melanesiae Schilder & Schilder, 1937 from New Britain.
E. onyx nymphae (Jay, 1850) from Chagos Archipelago to Mauritius. This taxon is discussed in Report-2).