A Review of the Labrid Fish Genus Labroides, with Descriptions of Two New Species and Notes on Ecology! JOHN E. RANDALL AN INDO-PACIFIC genus of smalllabrid fishes of nine dorsal spines, and in Riippell's mod­ (wrasses), Labroides Bleeker, is here restricted erately detailed description there is no men­ to four species, two of which are described as tion of a bilobed condition of the lower lip. new from islands of the tropical central Pa­ Fowler (1928: 331) (after Schmeltz) also cific. Underwater observations of all of the placed quadri/ineatus in Labroides and listed it species have revealed the unusual food habit from Samoa . I am dubious of this record . of removal of ectoparasites from other fishes. Possibly Schmeltz obtained the young of This is discussed for each species in the ac­ Labrichthys cyanotaenia Bleeker which have counts following taxonomic considerations. two lengthwise pale bands on the body (al­ though these are lower on the body of cyano­ Gunther (1862: 120) and Fowler (1949: taenia than they are on quadrilineatas and the 117) considered Diproctacanthus xanthums more ventral band is not as distinct). La­ Bleeker in the genus Labroides. I am in brichthys unilineata (Guichenot) from Guam agreement with de Beaufort (1940: 19, 151, is probably a synonym of Labrichthys cyano­ fig. 26) that the monotypic Diproctacantbus taenia, based on this juvenile color pattern. Bleeker is a valid genus. D. xanthums lacks Saville-Kent (1893: 308, col. pl. 16, figs. 4, the characteristic bilobed lower lip of La­ 9) described two species of Labroides, L. broidesand has two instead ofthree anal spines. bicincta and L. auropinna, after seeing them in Smith (1957: 100, 104) established a new coral pools of Lady Elliot Island reef in the genus, Fouilerella, for Labroides bicolor, princi­ Great Barrier Reef of Australia. He obtained pally on the basis of fewer lateral line scales no specimens, but preferred to "provision­ than dimidiatus. In view of the similarity of ally" give the fishes new names . Although bicolor to dimidiatus in other respects than the color drawings on which these names are number of scales, I refer Pow/ere/fa to the based are crude, it seems very likely that the synonymy of Labroides blue and black L. bicincta is a juvenile L. Smith included Labrus quadrilineatus Rup­ dimidiatm. Saville-Kent mentioned its "re­ pell (1835: 6, pl. 2, fig. 1) from the Red Sea semblance to the white and black banded L. with dimidiatus in the genus Labroides even dimidiatus, C. and V." Obviously he was not though its scale counts would seem to ally aware that the true life color of L. dimidiatus it with bicolor. Actually quadrilineatus prob­ is blue and black . The figure of L. auropinna, ably does not belong in Labroides, for this a blue fish with yellow fins, fits no known species has a completely scaled head (whereas species of Labroides. Until a more complete in Labroides the head is naked except for sub­ description with necessary meristic, measure­ orbital, postorbital, and opercular regions), ment, and detailed descriptive data on the a slightly emarginate caudal fin, eight instead species is available, I prefer not to recognize this name . It is possible that L. auropinna is 1 Contribution No. 209 from the Marine Labora ­ tory, University of Miami, Miami, Florida. Manuscript not a species of Labroides, and perhaps not received Ocrober 16, 1956. even a labrid. 327 328 PACIFIC SCIENCE, Vol. XII, October, 1958 The genus Labroides is distinguished from often distinct anteriorly on body and on other genera of the Labridae in having a small head) 2 mouth with thick lips, the upper with a shal­ 2a. Snout long, diameter of eye contained 2.1 low median groove and the lower divided to 2.5 times in snout length; caudal pe­ . into two prominent, anteriorly projecting duncle and caudal fin pale with a promi­ lobes. The inner surface of the lips has fleshy nent black crescent posteriorly in fin, the folds. There is a single pair of large, curved, attenuate ends of which extend to mar­ canine teeth anteriorly in each jaw, the upper gins of caudal peduncle (tropical Pacific) pair fitting inside the widely-spaced lower · Lab roides bicolor pair when the mouth is closed. There is a large, anteriorly directed, canine tooth at the 2b. Snout not long, diameter of eye contained extreme posterior part of the upper jaw, sep­ 1.5 to 1.9 times in snout length; caudal arated by a gap from anterior teeth. The peduncle and caudal fin black with upper remaining teeth are small, those in the lower and lower edges of fin pale 3 jaw in several close-set rows between the ca­ nines and those in the upper jaw forming a 3a. Median lateral black band which extends large mass just behind the anterior canines, pos teriorly from snout continuous with this mass with a marked indentation anteri­ black posterior half of body; no dusky orly in the mid-line. The body is compressed, streak on cheek below eye; pale edges of its width contained about 2,5 to 3 times in caudal fin magenta in life; maxim um the head length, and moderately elongate, its standard length in excess of 80 mm . depth contained about 3.5 to 4 times in the (Hawaiian Islands) . standard length . The caudal fin is truncate or ·. .Labroides phthirophagu s, n. sp. slightly rounded . The preopercle is entire, its 3b. Median lateral black band which extends margin smooth. The gill membranes are at­ posteriorly from snout merges gradually tached to the isthmus. The snout is pointed. to broad, pale-brown (dull-orange in life) The snou t, entire dorsal surface of the head, area in center of body; a narrow dusky chin, and throat are scaleless. The lateral line streak on cheek below eye running from is continuous, and the lateral line scales num­ chin to base of pectoral (may be faint in ber 28 or 52 to 54. Fin ray counts are as fol­ small adults ); pale edges of caudal fin lows: D IX, 11 or 12; A III , 10; P 13 (upper­ light lavender in life; maxim um standard most two rays unb ranched). The species are length about 60 mm. (Society Islands small, individual fish usually being less than and Tuamotu Archipelago) . 100 mm . in standard length. · Labroid es rubrol abiatus, n. sp. KEY TO THE SPECIES OF L ABROID ES J uvenile specimens for all species are un­ (Applicable primarily to adults ; available to me; however, all have been see discussion below concerning juveniles) viewed underwater, frequently in the proxim­ ity of adults. J uveniles of all four species ap­ 1a. Lateral line scales 52 to 54; color light pear to have the same basic color pattern, blue with a median lateral black band namely black with a broad band of color from snout to end of caudal fin (this band along the back which extends and narrows on broadening as it passes posteriorly on to snout. On L. dimidiatm and L. rubrolabiatus body) (Indo -Pacific) . this band is brilliant deep blue (these species . .. .. .. .. .Lab roides dimidiatu s are readily separable by scale counts; see key lb. Lateral line scales 28; color not as above above); on L. bicolorit is bright yellow; on L. (although a median lateral black band is phthirophagus it is bright purple. Review of Labroides- RANDALL 329 Labroides dimidiatus and Moorea, another color variant was ob­ (Cuvier and Valenciennes) served. Occasional adults have a dull red­ Fig. 1 orange region in the middle of the body be­ low and adjacent to the median black band. Labrus latovittatus Riippell, (non Lacepede), In the Marquesas L. dimidiatus were seen with 1835, Neue Wirbelth., Fische ... , p. 2. a red-orange area which was longer and oc­ Cossyphus dimidiatus Cuvier and Valenciennes, curred above as well as below the black band. 1839, Hist. Nat. des Poiss., vol. 13, p. 136. Barnard (1927: 749) described two color Labroides paradiseus Bleeker, 1851, Natuurk. varieties of the species at Natal, East Africa, Tijdschr. v. Nederland. Indie, vol. 2, p. 249. one with a dark stripe across the base of the Labroides bicincta Saville-Kenr, 1893, The pectoral fin and one without. He stated that Great Barrier Reef of Australia, p. 308, pl. the color of the species in Africa is blue or 16, fig. 4. yellow with a black longitudinal band. Smith Labroides caeruleo-lineatus Fowler, 1945, Acad. (1949: 291), also reporting on the species Nat. Sci. Phila:, Proc., vol. 97, p. 65, fig. 7. from East Africa, described the color as vary­ ing rapidly from light pink through straw TYPE LOCALITY: Mauritius. yellow to dark blue, apparently at will and This blue and black species is the most according to the emotional state of the fish. I common and widespread of the genus,rang­ have never seen L. dimidiatus in the Pacific ing from Africa to the rropical Pacific (where pink or yellow instead of blue, nor have I it is recorded from most major island groups). observed any rapid color changes. With age Labroides paradiseus Bleeker differs from there is a loss of brilliance and a lightening of dimidiatusin having a hooklike ventroanterior the blue color. Below the median black band extension of the broad black band in the large adults are nearly white. caudal fin. I have observed various degrees of A juvenile specimen, 24 mm. in standard intermediacy between typical dimidiatus and length, collected by the author in Tahiti, was rhe paradise!Is form, and I regard the latter as colored in life as follows : black with a band a color variety, as did Gunther (1881: 243).