Molecular phylogenetic analysis of slender salamanders, genus Batrachoseps(Amphibia : Plethodontidae), from central coastal California with descriptions of four new species

Plethodontid salamanders of the genus Batrachoseps comprise a clade Of Morp hologically similar, elongate species whose great genetic diversity is bein g revealed through molecular studies. We used allozymes and mtDNA sequences to study variation in 62 populations from central coastal California, trea ted most recently as members of the B. pacificus complex. Analyses of mtDNA data identify four lineages that arc well differentiated from each other a nd do not form a monophyletic group. instead, the central coastal lineages are multiply paraphyletic with respect to the southern California members o f the pacificus group. Marked allozymic differences show that these four li neages are strongly, differentiated, although some limited gene exchange ma y have occurred in the past, Each lineage is also morphologically distincti ve, but the differences between them are subtle. Because these lineages app ear to be evolving independently, we describe them as new, species: B. luci ae, B. incognitus and B. minor, distributed parapatrically from north to so uth in the Santa Lucia Mountains of coastal Monterey and San Luis Obispo Co unties. and B. gavilanensis, occurring mainly inland from the range of B. l uciae, centered on the Gabilan Mountains, but also extending to the Pacific coast at the north end of the range of the complex, along the northern bor der of Monterey Bay. Although no sympatry is known among any Of the new spe cies, B. luciae and B. gavilanensis are narrowly parapatric. Furthermore, a ll but B. luciae occur in sympatry with other members of the genus in at le ast a part of their geographic ranges. The new species may have arisen vica riantly with respect both to each other and to related forms in southern Ca lifornia, in part as a result of the dramatic tectonic movements that have characterized the last 15 million years of geological history in western No rth America.