PTEROCAESIO TESSELLATA (ACTINOPTERYGII: PERCIFORMES: CAESIONIDAE) FROM TAIWAN: EXTENDED DISTRIBUTION RANGE

extended Abstract. Six species of the genus Pterocaesio (Caesionidae) have previously been recorded from Taiwanese waters. Although Pterocaesio tessellata Carpenter, 1987 is known from the eastern Indian to the western Pacific oceans north to the Philippines, it has not previously been reported from Taiwan. The main objective of this paper is to document the presence of this species in the waters of Taiwan. A single specimen (101.6 mm standard length) of Pterocaesio tessellata was collected from south-western Taiwan in 2018. The morphology and fresh coloration of the collected specimen are herein described. The majority of the morphological characters closely align with the original descriptions of holotype and paratypes of Pterocaesio tessellata : dorsal fin with 10 spines and 15 soft rays; anal fin with 12 soft rays; pectoral fin with 20 rays; lateral-line scales 73; circumpeduncular scales 13 + 15; a single yellow longitudinal stripe on body lateral, about a single scale wide, from upper margin of eye to caudal peduncle, covering lateral line for most of its length. Therefore, the specimen from south-western Taiwan is identified as Pterocaesio tessellata . The presently reported specimen represents the first record for Taiwan, as well as the northernmost record of this species up to now. An identification key to the species of genus Pterocaesio in Taiwan is shown.

A single specimen of Pterocaesio tessellata Carpenter, 1987 was recently collected off Kaohsiung south-western Taiwan. This species has been known from the eastern Indian and western Pacific oceans north to the Philippines (Carpenter 1987). The presently reported specimen is herein described as the first record of P. tessellata from Taiwan and the northernmost record of this species. In addition, an identification key to the seven species of genus Pterocaesio present in Taiwanese waters is included along with photographs of congeners of the present species.

MATERIALS AND METHODS
Counts and measurements follow Carpenter (1987

RESULTS
Family Caesionidae Pterocaesio Bleeker, 1876 Pterocaesio tessellata Carpenter, 1987 単帯鱗鰭烏尾鮗 (New Taiwanese name) Fig. 1; Table 1 Pterocaesio tessellata Carpenter, 1987;Carpenter 1987 Table 1.) Body moderately elongate and fusiform; depth of caudal peduncle less than 1/3 of body depth. Head pointed; dorsal profile of head equally sloping. Interorbital space convex. Anterior nostril with low membranous rim, closer to orbit than snout; posterior nostril without rim or flap. Margin of opercle with dorsoposterior flap. Lateral line nearly straight from upper end of opercle to middle of caudal-fin base.
Mouth oblique, forming angle of about 40º to horizontal, lower jaw projecting slightly; maxilla extending posterior to vertical at anterior edge of orbit. Jaws with minute conical teeth; premaxilla with single row of teeth restricted to anteriormost portion; lower jaw with single row of teeth laterally, becoming patch anteriorly; teeth in lateral row distinctly less numerous just posterior to apex of jaw; vomer and palatines edentate. Origin of dorsal fin posterior to vertical above pelvic-fin origin; 1st dorsal-fin spine short, its base close to base of 2nd spine; dorsal-fin spines and soft rays anterior to 5th dorsal-fin spine gradually shorter. 1st of anal fin below base of 1st soft ray of dorsal fin; 1st spine of anal fin shorter than 2nd and 3rd spines; first soft ray of anal fin longest. Dorsal and anal fins scaled, dorsal with 4/5-1/2 of its greatest spinous height covered with scales. Pectoral fins pointed, 5th ray longest, reaching vertical drawn through base of 8th spine in dorsal fin. Origin of pelvic fin slightly posterior to lower base of pectoral fin. Caudal fin deeply forked. Coloration-When fresh, body and head pink, dark red dorsally; a single yellow longitudinal stripe on body lateral, about a single scale wide, from upper margin of eye to caudal peduncle, covering lateral line for most of its length; snout faintly yellowish. Dorsal-fin faint yellowish with pink outer margin; anal fin and pelvic fin pinkish white; pectoral fin pinkish translucent, axil black; caudal fin red with dark red to brown blotch on tip of upper and lower lobes. When preserved, body and head pale with dark pigments on centre of scales of body lateral; longitudinal stripe disappeared; dark blotch on tip of caudal-fin lobes. Distribution. Pterocaesio tessellata is currently known from the eastern Indian to the western Pacific oceans, westward to Sri Lanka, eastward to Vanuatu, and north to the Philippines (Carpenter 1987, 2001, Allen and Erdmann 2012, Tatsukawa 2017, and now from southwestern Taiwan (presently reported study).

DISCUSSION
The majority of morphological characters of the presently reported specimen are consistent with those of the holotype and paratypes of P. tessellata given by Carpenter (1987): dorsal fin with 10 spines and 15 soft rays; anal fin with 12 soft rays; pectoral fin with 20 rays; lateralline scales 73; circumpeduncular scales 13 + 15; a single yellow longitudinal stripe on body lateral, about a single scale wide, from upper margin of eye to caudal peduncle, covering lateral line for most of its length ( Table 1). The length of caudal peduncle length and length of 2nd dorsalfin spine of presently reported specimen differed 0.1% from the holotype and paratypes. These small differences are herein simply considered as intraspecific variations.
Among its congeners, P. tessellata is similar to P. chrysozona, P. digramma, and P. marri, sharing a longitudinal stripe covering lateral line with two distinct blotches on the tips of each caudal-fin lobes (Carpenter 1987) (Fig. 2). Pterocaesio chrysozona also has only one stripe on body side, but has another upper stripe on dorsal midline along base of dorsal fin (vs. absent in P. chrysozona). In addition, the mid-lateral stripe of Pterocaesio chrysozona is broader anteriorly, the width of two or three scales (vs. a stripe of a single width throughout), and directly below lateral line in anterior and above lateral line on caudal peduncle (vs. covering lateral line throughout).  Pectoral-fin rays  Pectoral-fin length 25.5 26.7 26.4-29.5 Pelvic-fin length 17.5 16.3 16.0-17.7 Pelvic-fin spine length 12.3 11.9 11. 5-12.5 Length of 1st dorsal-fin spine  Pterocaesio tessellata has not been previously recorded from Taiwanese waters, and the northernmost record of the species was from the Philippines (Carpenter 1987, Tatsukawa 2017. The specimen collected from south-western Taiwan represents the first record of P. tessellata from Taiwan and, the northernmost record of the species. Combined with Koeda and Ho (2018), two species of genus Pterocaesio are newly reported from Taiwan, bringing the total number of Pterocaesio species known from Taiwan to seven. An identification key to the species of genus Pterocaesio in Taiwan is provided below (Table 2).