Branchiostegus saitoi, Dooley, James K. & Iwatsuki, Yukio, 2012

Dooley, James K. & Iwatsuki, Yukio, 2012, A new species of deepwater tilefish (Percoidea: Branchiostegidae) from the Philippines, with a brief discussion of the status of tilefish systematics, Zootaxa 3249, pp. 31-38 : 32-34

Branchiostegus saitoi sp. nov.

Holotype. Deposited at University of Miyazaki, Division of Fisheries Science, Miyazaki, Japan; [ MUFS 36081], male, 329 mm SL; hook and line, Batangas, Laiya, Philippines, 13 0 38.4’ N, 121 0 25.6 E; 14 April 2011; 210 m depth, rocky-sand bottom; photographed fresh, tissue sample taken.

Paratype. Deposited at the Division of Fishers, National Museum of Sciences, Tokyo, Japan; [NSMT-P 106562], male, 315.6 mm SL; hook and line, Batangas, Laiya, Philippines, 13 0 38.4’ N, 121 0 25.5’ E; 14 April 2011; 220 m depth, rocky-sand bottom; no fresh photograph taken; muscle tissue sample taken.

Diagnosis. This species can easily be distinguished from its congeners by the following combination of characters: a great body depth (28–29% SL; other species usually 27% SL) longer head length (30–31% SL; other species usually 28%), head profile oblique, about 130 degree angle (other species usually 95–130 degrees); head depth (26–27% SL; other species usually 26% SL); eyes high on head (interorbital width 31–34% HL); small orbital diameter 24–25% HL, only B. sawakinensis and B. albus with small orbital diameters, 23–24% HL) long predorsal length (35% SL; other species usually 30–32% SL, rarely 33–34% SL), deep body (28-29% SL; other species usually 24–27%, rarely, only in B. japonicus and B. semifasciatus , 28–29% SL); wide body (14–15% SL; other species usually 11–13% SL); number of first arch gill rakers low 18 + 1 rudimentary, most other species 18–24, modally 19–22.

Fresh colouration includes: Upper body rosy red with flecks of pearly-silver scales and pearly pinkish-silver lower body and anterior lower throat regions; dorsal to pectoral to about the lateral line with a large golden yellow area with a silver central patch; lower head region bluish-white from about a horizontal line from lower cheek above the preopercular angle to the pectoral fin base; lateral head metallic golden from anterior orbit to about midorbit dorsally ( Fig. 1 ); B. saitoi also has distinct head, tail and body fresh colouration: a prominent dark predorsal ridge overlying yellow-orange pigment reaching to a vertical above the anterior orbital rim ( Figs. 1–3 ); (a dark more prominent predorsal ridge found only in B semifasciatus from West Africa, but it lacks underlying yelloworange colour); upper lip orange-yellow (over maxillary) and white (over premaxillary and mandible) iris goldengreen; snout reddish; lateral head from above about mid orbit to top of head red; skin over dorsal tips of branchiostegals characteristically bright yellow ( Fig. 3 ); dorsal fin membrane translucent pink, yellow distally along entire margin of the fin; and anal fin membranes translucent to pinkish white; pelvics white with overlying yellow; dorsal upper pectoral rays dusky, ventral half yellow; caudal characteristically coloured among all congeners (although somewhat similar to B. wardi ); a central translucent horizontal band, most of the area dorsal to the band bright yellow, upper margin black with outer margin white; below the clear central caudal band also bright yellow for about one third of the ventral caudal area, followed by a little more than third of the caudal black then a little less than a third of the ventral caudal white ( Figs. 1 , 2 and 5 ).

Description (parentheses denotes paratype, if different from holotype) Dorsal fin rays VII,15, first dorsal spine 1.4 into second spine, dorsal fin origin over pectoral fin base, dorsal long and continuous, greatest height of dorsal fin 13% SL (11%), base length 58% SL (56% SL), antepenultimate ray elongate 18% SL; anal fin rays II,12, anal fin origin under and between dorsal fin rays 4 and 5, dorsal long and continuous, greatest height 12.6% SL (10% SL), base length 28% SL, penultimate ray elongate, 10% SL; pectoral fin rays 18, length 26% SL; pelvic fin I,5, length 14% SL (15%); caudal margin double scalloped; (from radiographs) principal caudal fin rays 17; procurrent caudal rays 10 (upper) + 9 (lower); 1 uroneural and parhypural, 3 epurals, and 2+3 autogenous hypurals; preopercular angle about 90 0 with fine serrae (about 52) on upper limb, a slight indention near preopercle angle (like B. albus ), no serrae on lower limb of preopercle; scales ctenoid (in pockets) over most of body, cycloid in head region; scale rows to orbital rim 11 (12) and with free margins, (not imbedded as in B. japonicus ); 7 opercular free scale rows, no enlarged spine at opercle angle (only a single blunt spine); 7 (8); scale rows above the lateral line; scale rows below the lateral line 23 (24); interoperculum not scaled; 49 (50) pored lateral line scales to hypural crease plus 1 (2) on tail; first arch gill rakers (upper limb + lower limb) 7 +11 + 1 rudimentary; total gill rakers on all four arches 49 (51) (incl. rudimentary gill rakers); vertebrae 24 (10+14); predorsal fin support formula 0-0-2-; preopercular length 78% HL; (snout to upper margin of operculum); head profile oblique about 50o angle ( Fig.2 ); well developed supraoccipital crest; jaws terminal and slightly inferior, upper jaw protrusile; maxillary extends posteriorly to below mid-pupil ( Figs. 1 3 ); upper jaw with fine canine teeth in 2 3 rows on each side widening anteriorly to a patch on either side of jaw symphysis; with an enlarged tooth at the rear of jaw; lower jaw similarly with rows of fine canines terminating in a patch on either side of the symphysis; no teeth on palatine, vomer, tongue; pharyngeal canine teeth well developed 5 mandibular pores unilaterally (as with most congeners); first haemal spine over second anal-fin spine with parhypophyses fused medially into an arch for the rear projection of the swimbladder, first haemal spine forming a broad blade ventrally (varies among congeners).

Distribution. Known only from Bayangas, Laiya, Philippines (13 0 38.5’ N, 121 0 25.6’ E) at 210–220 M depths, it is possibly endemic; but as it is very rare, and probably inhabits burrows as do other tilefishes, B. saitoi may ultimately be found at other localities.

Etymology. A new species of Branchiostegus was first caught off Batangas Laiya, Philippines in 2009, photographed and eaten. Two years passed before two more specimens were caught by J. Saito, an amateur angler from Japan in April, 2011. Without J. Saito’s considerable efforts and interest, this species would have remained unknown. The new species is herein named in his honor.

Figures

FIGURE 1. Fresh colouration of 329 mm SL (holotype, MUFS 36081) specimen of B. saitoi caught by hook and line, 14 May 2011, Batangas, Laiya, Philippines; photo by J. Saito.

FIGURE 2. Freshly preserved holotype 329 mm SL; photo by the second author.

FIGURE 3. Head of the holotype of B. saitoi (329 mm SL); photo by J. Saito.

FIGURE 5. Freshly preserved colouration of the tail of B. saitoi, 329 mm SL (holotype) photo by the second author.