Meeting Abstract
124.4 Tuesday, Jan. 7 14:15 Trans-Pacific invasion drives North Pacific limpet (Lottiidae) species diversification EERNISSE, D.J.*; PILGRIM, E.M.; MARKO, P.B.; Cal State Fullerton; U.S. EPA, Cincinnati, OH; Univ. of Hawaii at Manoa deernisse@fullerton.edu
Limpets were collected from the intertidal of cooler high latitude portions of the northwest Pacific (NWP) and sequenced for two mitochondrial gene regions, 16S and COI, and nuclear cytosolic malate dehydrogenase (cMDH). We resolved about eight limpet species based on combined gene analysis, and these also differ in their morphology, but matching these to nominal species remains a challenge. The species differed on protected vs. exposed coasts of Hokkaido Island, Japan, and Vostok Bay, Sakhalin Island, and the Pacific coast of Kamchatka Peninsula all in Russia. Pacific and Sea of Japan coasts mostly differed in their limpet fauna. Further south, the species likely differ again. We found no overlap with three other “tsunami debris” species washed up on beaches in Oregon and Washington but originating just south of Hokkaido on northeastern Honshu Island, a different faunal province, and the site of the devastating 2011 tsunami. The striking pattern of regional differences in NWP limpets observed could be due to factors such as differences in temperature tolerance or barriers to larval dispersal. Combined analysis with available sequences and our various unpublished data sets representing most northeastern Pacific (NEP) Lottiidae species reveals that NWP species do not group with each other but are scattered across this NEP-dominated phylogeny. The results imply there have been at least seven separate trans-Pacific invasions over geological time. Collectively, the NWP/NEP species comprise a monophyletic endemic North Pacific radiation. Only one species, the shield limpet or Lottia pelta (Eschscholtz 1833), was distributed on both sides of the Pacific, but with greater mitochondrial haplotype diversity on the NWP side. This intriguing result could indicate a geologically recent invasion of the NEP by L. pelta vagabonds, now widespread.
