Xyrichtys koteamea, Randall & Allen, 2004

Randall, John E. & Allen, Gerald R., 2004, Xyrichtys Koteamea, A New Razorfish (Perciformes: Labridae) From Easter Island, Raffles Bulletin of Zoology 52 (1), pp. 251-255 : 253-254

Xyrichtys koteamea , new species

( Figs. 1 , 2 )

Novaculichthys woodi - Randall & Cea Egaña, 1984: 12 (Easter Island) (non Jenkins).

Material examined. – Holotype – BPBM 6715 , male, 194 mm, Easter Island , west coast off Rano Kau, 50 m, hook and line, coll. R. Ika, G. R. Allen & B. A. Baker, 13 Feb.1969.

Paratypes – USNM 375852 , male, 206 mm, Easter Island , off islets at southwest corner of island, 250 m, hook and line, local fisherman for J. E. Randall, 15 Feb.1969 ; ZRC 49157 , male, 202 mm, same data as preceding ; MNHNC 7227 , male, 197 mm, Easter Island , 75 m, hook and line, coll. local fisherman for J. E. Randall, 2 Feb.1986 .

Diagnosis. – Dorsal rays IX,12; anal rays III,12; pectoral rays 13; lateral-line scales 20 + 5; head naked except for one or two small partly embedded scales dorsally on opercle; gill rakers 16-18; body depth 2.6-2.75 in SL; dorsal profile of snout forming an angle of about 50; front of head with a slight median ridge; origin of dorsal fin a little posterior to preopercular margin; first dorsal spine flexible, slightly longer than second spine, 4.05-4.15 in head length; space between first two dorsal spines two-thirds space between second and third spines; caudal fin slightly rounded; pectoral fins short, 1.6-1.7 in head length; bright red, the edges of scales darker red; membranes of spinous portion of dorsal fin bluish gray, each with a black spot; each of first three membranes of soft portion of fin with a faint black spot. Attains at least 206 mm SL.

Description. – Dorsal rays IX,12; anal rays III,12; all dorsal and anal rays branched, the last to base; pectoral rays 13, the first rudimentary, the second unbranched; pelvic rays I,5; branched caudal rays 12; upper and lower procurrent caudal rays 5 or 6, the most posterior segmented; lateral-line scales 20 + 5; scales above lateral line to origin of dorsal fin 3; scales below lateral line to origin of anal fin 8; circumpeduncular scales 16; gill rakers 18 (16-18); pseudobranchial filaments of holotype 32; branchiostegal rays 6; vertebrae 9 + 16; supraneural (predorsal) bones 1.

Body depth 2.7 (2.6-2.75) in SL; body compressed, the width 2.9 (2.75-2.8) in body depth; head length 2.9 (2.95) in SL; dorsal profile of snout forming an angle of about 50 to horizontal axis of body; snout length 2.5 (2.45-2.5) in head length; orbit diameter 5.65 (5.5-5.9) in head length; front of head with a slight median ridge; interorbital width 4.1 (4.1- 4.15) in head length; caudal-peduncle depth 2.1 (2.0-2.15) in head length; caudal-peduncle length 3.4 (3.3-3.55) in head length.

Mouth terminal and very slightly oblique; maxilla extending to below posterior nostril, the upper-jaw length 3.2 (3.0-3.15) in head length. Lips slightly fleshy, the dorsal part of upper lip extending beneath anterior edge of snout except posteriorly; lower lip with a lateral flap extending along side of jaw, fitting flush with surface due to a recessed area behind; inner surface of lips papillose, interdigitating with teeth anteriorly in jaws. A pair of strong projecting canine teeth at front of jaws, strongly curved laterally and slightly recurved, the lowers fitting inside uppers when mouth closed; side of jaws with a row of about nine conical teeth, the last few notably smaller; anterior third of upper jaw with an irregular inner row of about seven small bluntly conical teeth, partly hidden in papillose tissue; side of lower jaw with a narrow inner band of small, close-set, nodular teeth. Each half of paired upper pharyngeal plate triangular with about 20 teeth, the most anterior largest and bluntly conical, the next two lateral teeth also bluntly conical, the remaining teeth small and nodular; slender median anterior limb of lower pharyngeal plate with four small sharply conical teeth, followed by an irregular double row of small nodular teeth; transverse limb of lower pharyngeal plate with a posterior row of 13 teeth, the median three as small molars, flanked by smaller nodular teeth, the most lateral a small blunt conical tooth. Tongue broadly rounded, the upper surface densely papillose.

Anterior nostril a very small membranous tube in front of center of eye by a distance equal to two-thirds orbit diameter; posterior nostril a short slit about half pupil diameter behind and slightly dorsal to anterior nostril. Sensory pores of head extremely small and difficult to detect. Free margin of preopercle reaching dorsally to level of a pupil diameter below orbit and extending anteriorly to below front edge of orbit.

Lateral line interrupted, the anterior series ending below ninth dorsal soft ray; first pored scale of peduncular series below eleventh dorsal soft ray; tubule of pored scales unbranched and nearly reaching posterior scale edge; head naked except for one or two small partially embedded scales dorsally on opercle (one on left side of holotype and two on right side); no median predorsal scales; a vertical row of four scales on nape below first dorsal spine, preceded by a row of four scales, the lowermost reaching to within two-thirds orbit diameter of eye. Two or three small, partly embedded, median prepelvic scales, and a small scale-like process between bases of pelvic fins. No scales on fins except base of caudal fin with four to five vertical rows, progressively smaller posteriorly, on basal third of fin.

Origin of dorsal fin slightly behind posterior preopercular margin, the predorsal length 3.6 (3.5-3.65) in SL; first dorsal spine flexible, 4.15 (4.05-4.15) in head length; second to ninth dorsal spines sharp-tipped, the second shorter than first, 4.75 (4.6) in head length; space between first two dorsal spines equal to two-thirds space between second and third spines; membrane between second and third dorsal spines not incised; eighth and ninth dorsal spines longest, 3.75 (3.55-3.85) in head length; sixth to eighth dorsal soft rays longest, 2.6 (2.5) in head length; origin of anal fin below base of first dorsal soft ray, the preanal length 1.75 (1.75-1.8) in SL; first anal spine 8.2 (7.55-8.85) in head length; third anal spine 3.75 (3.6-3.9) in head length; fourth or fifth anal soft rays longest, 3.45 (3.4-3.45) in head length; caudal fin slightly rounded and short, 4.7 (4.75-5.0) in SL; pectoral fins short, the first and second branched rays longest, 1.7 (1.6-1.7) in SL; origin of pelvic fins below upper base of pectoral fins, the prepelvic length 3.0 in SL; pelvic spine 4.5 (3.9-4.5) in head length; first pelvic ray filamentous, reaching to or beyond anus, 4.15 (4.05-4.7) in SL.

Color of holotype in alcohol: yellowish brown, the edges of scales darker than centers; head paler yellowish brown than body; spinous portion of dorsal fin blackish, each membrane with a black spot behind preceding spine about half way to margin of fin; soft portion of dorsal fin dusky with a similar but fainter spot on first three membranes at same level as spinous portion of fin, continuing progressively less pigmented for a few more membranes; anal fin pale yellowish; caudal fin with dusky membranes and pale rays, the basal scaled part colored like body; pectoral fins with pale rays and blackish membranes dorsally, progressively less pigmented ventrally; pelvic fins pale.

Color of holotype when fresh ( Fig. 1 ): bright red, edges of scales darker red; membranes of spinous portion of dorsal fin bluish gray, each with a black spot approximately half pupil size about half way to spine tip, closer to anterior than posterior spine; soft portion of dorsal fin light red, membranes streaked with white on about basal half, first three membranes with a blackish spot as seen on spinous membranes, but more diffuse; anal fin colored like soft portion of dorsal fin but without any dark markings; caudal fin with light red rays and dusky light red membranes; pectoral fins with light red rays, outer half of membranes blackish red, becoming progressively less pigmented ventrally; pelvic fins with light red rays and white membranes.

Etymology. – Named koteamea from the Rapanui word for the fish. Kotea is “generic” for three species of wrasses, and mea in Rapanui means red.

Remarks. – Although presently known only from Easter Island, this razorfish might be expected from southern subtropical islands to the west such as the Pitcairn Islands and Rapa, where fish collections have been made mainly in shallow water.

The most obvious differences of Xyrichtys koteamea from X. woodi are its much larger maximum size and color pattern. Although both have the series of black spots, one per membrane on the anterior half of the dorsal fin, and X. woodi can be light red dorsally on the body, it is not overall deep red in color. Furthermore, adults of X. woodi have oblique dark red to black lines ventrally on the otherwise white lower abdomen (at least when alive or freshly caught), as shown by Severns & Fiene-Severns (1993: 40) and Randall (1996: 133, lower fig.). These markings were the basis for Jenkins (1900: 53, fig. 9) describing Novaculichthys entargyreus on the page following his description of N. woodi , the former now a synonym of the latter. Also, Seale (1901: 5, fig. 2) named another junior synonym, Novaculichthys tattoo , for the same markings. These distinctive abdominal lines are not present on X. koteamea . In addition, X. koteamea differs from X. woodi in having a deeper body, the depth 2.6-2.75 in SL, compared to 2.75-3.0 for X. woodi , and shorter pectoral fins, 1.6-1.7 in head length, compared to 1.4-1.55 for X. woodi .

All four specimens of X. koteamea are males. Because male razorfishes attain larger size than females, and because Easter Islanders fish for the larger fishes for food, they use hooks of moderate to large size. The x-ray of the 202-mm paratype ( Fig. 2 ) shows the hook that caught the specimen. Knowing the relatively small mouth of razorfishes, it is remarkable that this fish swallowed so large a hook. It is doubtful that even a large female of this species could take a hook of this size.

Figures

Fig. 1. Holotype of Xyrichtys koteamea, male, BPBM 6715, 194 mm SL, Easter Island, 50 m (J. E. Randall).

Fig.2. Print from x-ray of 202-mm paratype of Xyrichtys koteamea showing the hook that caught the specimen.