syntype

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. One of two or more specimens cited by the author of a name of a species or subspecies when no single specimen was selected as the holotype.
2. n. One of two or more specimens simultaneously selected as types by the original author of a name of a species or subspecies.

Century Dictionary and Cyclopedia

1. n. In the nomenclature of types in natural history, any specimen of the original series (from which a species has been described and named) when there is no holotype: same as cotype.

Wiktionary

1. n. biology Any of several specimens selected as types for the name of a species