Corella species in the American Pacific Northwest: distinction of C. inflata Huntsman, 1912 from C. willmeriana Herdman, 1898 (Ascidiacea, Phlebobranchia)

Abstract

The solitary phlebobranch ascidian Corella inflata, originally described by Huntsman in 1912 but later synonymized with C. willmeriana Herdman, 1898, is now reinstated as a separate species based on comparative morphology of adults, sperm, and tadpoles. Corella inflata is probably largely or completely self-fertilizing, broods its eggs and embryos until well after hatching of the tadpole larvae, and is confined in its distribution to shallow-water (0.1–18 m depth) areas of northwestern Washington and British Columbia. Corella willmeriana appears to be both self- and cross-fertilizing, does not brood its eggs, and is more widespread in distribution, occurring from southern Alaska to southern California and at least as deep as 50 m; it is rarely encountered at the sea surface. The two Corella species differ morphologically from the European Corella parallelogramma and the Japanese C. japonica and C. japonica asamushi. Differential spawning latencies are discussed and the possibility that C. inflata evolved through stasipatric speciation is proposed.