Sleuthing cryptic Chromodorids (Mollusca, Nudibranchia): adding to Philippine marine biodiversity

The Verde Island Passage of the Philippines is renowned for its rich marine biodiversity and heterobranch mollusks are demonstrable models of that species richness of the region. Chromodorid nudibranchs represent a particularly rich taxon, with species of Chromodoris being one of the most iconic and abundant taxa in shallow water coral reef environments. Despite being one of the best-documented clades of nudibranch mollusks, recent work has shown that numerous cryptic and pseudocryptic species are abundant in the waters of the Coral Triangle region. This paper reviews the species richness and distribution of Chromodoris species in the Philippines and provides a description of a new species of Chromodoris from the region. Chromodoris alcalai Gosliner, n. sp. is named to honor Dr. Angel Alcala’s 90th birthday and his pioneering contributions to preserving the marine biodiversity of the Philippines. This species is most similar externally to C. dianae Gosliner and Behrens, 1998, with which it was erroneous lumped. Distinctness of molecular data, external morphology and coloration, and internal anatomical features clearly distinguish these two species. KEYWORDS: systematics, Nudibranchia, coral reefs, Indo-Pacific, Coral Triangle