On the absence of previously reported Japanese and Peruvian species of Prionitis (Halymeniaceae, Rhodophyta) in the northeast Pacific

Partial rbc L sequences of type specimens, historically significant specimens and recently collected comparative specimens are used to demonstrate that Prionitis decipiens (Montagne) J. Agardh (type locality: Paita, Peru), Prionitis angusta (Harvey) Okamura (type locality: Shimoda, Japan, currently known as Grateloupia angusta (Harvey) Kawaguchi et Wang) and Prionitis cornea (Okamura) E. Y. Dawson (type locality: Shizuoka, Japan, currently known as Grateloupia cornea Okamura), all previously reported from the northeast (NE) Pacific (California, USA and Baja California, Mexico), were not, and currently are not, present. Historically significant specimens from the NE Pacific specifically annotated by E. Y. Dawson as belonging to P. cornea or specifically annotated by I. A. Abbott as belonging to P. angusta were sequenced and shown to belong to either Prionitis linearis Kylin (type locality: La Jolla, California, USA) or to Prionitis filiformis Kylin (type locality: San Francisco, California, USA). The lectotype of Gelidium decipiens Montagne (basionym of Prionitis decipiens ) is narrowed to a single specimen illustrated by Montagne, and a lectotype is designated for P. linearis . The utility of partial rbc L sequences (less than 200 base pairs) for determining the identity of specimens is discussed, as is the importance of sequencing type and historically significant specimens.