Chelidoperca tandstadae, a new species of perchlet (Perciformes: Serranidae) from the southwestern Indian Ocean

A new species of perchlet of the genus Chelidoperca is described based on 21 specimens, 72.8–111.8 mm SL, collected off Madagascar, Mozambique, and Tanzania at depths of 130–271 m. Thirteen specimens were collected during bottom-trawl surveys conducted by the R/V Dr. Fridtjof Nansen in 2007, 2010, 2023, and 2025, and 8 additional specimens, collected off Madagascar in 1973 and 2009, were found in the collections of the Muséum national d’Histoire naturelle (MNHN), Paris, France. Chelidoperca tandstadae n. sp. is distinguished from all congeners by the following combination of characters: three (two full-sized plus one about half-sized) scale rows between the lateral line and middle of the spinous-dorsal-fin base; 40–43 pored lateral-line scales; 15–16 pectoral-fin rays; 16–18 total gill rakers on the first gill arch, including 9–11 developed gill rakers; the posterior margin of caudal fin truncate; the scale rows on the interorbital area extending anteriorly to the level of the mid-orbit; scales on the lower jaw restricted to angular; a faint, sometimes indistinct, discontinuous, longitudinal series of small, irregular, dark, blotch-like segments mid-laterally on body; the dorsal-fin with irregular, yellowish-brown and white spots along the basal three-fourths of the spines and the basal half of the rays; alternating yellowish-brown and white, short bands along the proximal half of the dorsal margin of the caudal fin; a few scattered yellow streaks along the central caudal-fin rays; and an orange-red, blotch-like marking on the lower caudal-fin lobe. The validity of the new species is further supported by a minimum interspecific COI sequence divergence of 8.91% Kimura two-parameter (K2P) distance from the congeners included in the analysis. Chelidoperca occipitalis is the morphologically most similar species to C. tandstadae and was recovered as its sister lineage in the phylogenetic analysis. Previous records of C. occipitalis from the southwestern Indian Ocean are herein attributed to the new species, making C. tandstadae the only species of the genus currently known from the region.