Cirrhilabrus isosceles Tea, Senou & Greene, 2016
Pintail fairy-wrasse
Cirrhilabrus isosceles
photo by Tea, Y.-K.

Family:  Labridae (Wrasses), subfamily: Cheilininae
Max. size:  10 cm SL (male/unsexed)
Environment:  reef-associated; marine; depth range 24 - 60 m
Distribution:  Western Pacific: Japan (Izu-Oshima), south to the Ryukyu Archipelago (Yaeyama Islands and Okinawa), Taiwan (Green Island), and the Philippines.
Diagnosis:  Dorsal spines (total): 11-11; Dorsal soft rays (total): 9-9; Anal spines: 3-3; Anal soft rays: 9-9. This species is distinguished by the following characters: D XI,9; A III,9 except holotype with III,8; pectoral-fin rays 14-15; lateral line interrupted with 16-17 + 6-8 scales; median predorsal scales 4-5; 2 horizontal scale rows on cheek below eye; gill rakers 15; body depth 29-34% SL; head length 29-36% SL; snout length 9-11% SL; caudal fin of terminal-phase (TP) male is broadly lanceolate, i.e. rhomboidal with an extension of central rays; pelvic fins are relatively short, not reaching anal-fin origin when depressed; colour of TP male in life orange-yellow dorsally suffusing to lavender ventrally; a bright pink-to-purplish stripe at rest and dead, but blue in life and especially when displaying, extending posteriorly from upper orbit across head before making an oblique downward slant behind pectoral-fin base, and then continuing just below mid-lateral line to base of caudal fin; a prominent long mid-dorsal-fin basal dark spot, with a mostly lavender blotch on upper body below spot; colour of initial-phase fish mainly uniformly orange with faint stripes along dorsum and weak manifestation of medial stripe (Ref. 108439).
Biology:  Occurs in areas with flat or gently sloping bottoms with scattered low outcrops of rock and coral (Ref. 108439).
IUCN Red List Status: Not Evaluated (N.E.) Ref. (130435)
Threat to humans:  harmless
Country info:  In addition to the paratypes from Cagayan Province on the northern tip of the Philippines, Aldren Delegencia reported collections from the Verde passage south of Luzon, where it is significantly less common and further reported to extend to Cebu in the central Philippines, where it is rare and most likely represents the southernmost limit of its distribution (Ref. 108439).


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