Pseudanthiashangapiko sp. nov. (Teleostei, Serranidae, Anthiadinae) is herein described from three specimens collected from a depth of 83 m in a mesophotic coral ecosystem off Hanga Piko, Rapa Nui (Easter Island), Chile. Pseudanthiashangapiko sp. nov. can be distinguished from its congeners in live coloration and by the following combination of characters: dorsal-fin rays X, 17; anal-fin rays III, 8; pectoral-fin rays 16 (left side of one specimen 17); vertebrae 10+16; scales relatively large, two scales above lateral-line to base of fifth dorsal spine, and 16-17 circumpeduncular scales; gill rakers 11+23; and a slender body, with greatest body depth 3.6 (3.4-3.8) in SL. The most similar DNA barcodes (mitochondrial COI gene) are from Pseudanthiasventralis Randall, 1979 and Pseudanthiashawaiiensis Randall, 1979, with 16.8% and 17.0% uncorrected divergence, respectively. This fish is one of four new species that were documented from a pair of technical dives at a single location in Rapa Nui, emphasizing the high number of undescribed species likely still unknown in mesophotic coral ecosystems, especially in geographically remote locations. Pseudanthiashangapiko sp. nov. adds to the Rapa Nui ichthyofauna, which hosts the second-highest level of endemism in both shallow and deep-water fishes.
Keywords: Biodiversity; coral-reef twilight zone; ichthyology; island; mesophotic coral ecosystem; reef fish; taxonomy.
Bart Shepherd, Hudson T. Pinheiro, Tyler A. Y. Phelps, Alejandro Pérez-Matus, Luiz A. Rocha.