Mussel of the

Page last updated
30 June 2006

Mussel of the Month

The July 2006 Mussel of the Month is Castalia ambigua. The genus Castalia belongs to the family Hyriidae and is endemic to South America.

Castalia ambigua
FMNH 67901. Alto Yavarí, zone of mouth of Rio Yaquerana, Loreto, Peru,
Celestino Kalinowski, 16 August 1957!

One of the families of freshwater mussels known to inhabit South America is the Hyriidae. On that continent, the hyriids can be divided into three tribes, each with a reasonably distictive set of shell characters: the Rhipidodontini (e.g., Diplodon), the Hyriini (e.g., Prisodon) and the Castaliini.

The castaliines, like Castalia, Castaliella, etc., are generally trigonal in outline, with high umbos and usually with radial sculpture covering most of the disk. An interest feature of many specimens is the rough serration found on the hinge teeth.

An interesting feature of Castalia and the other Neotropical hyriids is that their nearest relatives, the Hyridellini, are know from Australia!


Phylum Mollusca
Class Bivalvia
Subclass Palaeoheterodonta
Order Unionoida

Superfamily Etherioidea DeShayes, 1830

Family Hyriidae Swainson, 1840
Subfamily Hyriinae s.s.
Tribe Castaliini Lange de Morretes, 1949

Genus Castalia Lamarck, 1819

Species Castalia ambigua Lamarck, 1819

For more information on Castalia and the Neotropical hyriids, check out:
  • Bonetto, A.A. 1965. Las almejas Sudamericanas de la Tribu Castaliini. Physis (Buenos Aires) 25(69): 187-196.
  • Parodiz, J.J., A.A. Bonetto. 1963. Taxonomy and zoogeographic relationships of the South American Naiades (Pelecypoda: Unionacea and Mutelacea). Malacologia 1: 179-214.
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