Description

SINGLE PAPER

Volume 12, Issue 1 – November 2006

Gerald R. Allen and Mark V. Erdmann: Paracheilinus walton, a new species of flasherwrasse (Perciformes: Labridae) from Papua, Indonesia with a key to the species of Paracheilinus, pp.11-18

Abstract

The Indo-Pacific labrid fish Paracheilinus walton is described from four male specimens, 34.8-40.7 mm SL, and two females, 27.7-38.9 mm SL, collected in 46 m at Yapen Island, Papua, Indonesia. It most closely resembles the sympatric P. cyaneus (South China Sea to Solomon Islands), but differs most noticeably with regards  to its smaller maximum size (about 45 vs. 55 mm SL ) and lower number of elongate dorsal rays (3-4 vs. 6-8) in males. There are also significant differences in the “flasher” courtship pattern of males of the two species. Paracheilinus walton has a white to slightly yellowish dorsal fin that contrasts vividly with the intense red colour (black when viewed under ambient light) of the adjacent back compared to the brilliant turquoise blue to whitish dorsal fin and back of P. cyaneus. Moreover, there is a pronounced difference in the shape and orientation of the elongate filaments. In P. walton these are relatively broad and uniform in width throughout their length, terminating in rounded, club-shaped tips. When fully erect, the distal third of the protruding rays are curved posteriorly. In contrast, the slender, tapered rays of P. cyaneus are not rigidly curved posteriorly. A key is given to the 15 species of Paracheilinus.