holotype
noun
- single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described
Wiktionary
noun
Etymology: From holo- + -type.
- The single physical example (or illustration) of an organism used to formally describe the species (or lower-order taxon), subsequently to be kept as a reference.
“The holotype of this species is subglobular in shape and ammoniticonic in its mode of growth.”
“The surface of the holotype bears seven rounded annulations which slope very slightly orad from the venter.”