Synodus tectus Cressey 1981

Synodus tectus

MATERIAL EXAMINED.—Holotype: USNM 218935, SL 175 mm, Visayan Sea, PHILIPPINES, 41 fms, 5 Jun 1978, coll. L. Knapp. Paratypes: USNM 136223 (1), SL 83 mm, PHILIPPINES, Albatross, off Corregidor Light, 38 fms, 2 Jan 1908; USNM 217762 (2), 73–133 mm, SOUTH CHINA SEA, Macclesfield Bank, R/V Cape St. Mary, Sta 19, 76.8–80.5 m, 13 Jun 1964, coll. W. L. Chan; USNM 217763 (1), SL 90 mm, SOUTH CHINA SEA, Macclesfield Bank, R/V Cape St. Mary, Sta 51, 80.5–87.8 m, 18 Jun 1964, coll. W. L. Chan; USNM 217766 (1), SL 119 mm, Manila fish market, PHILIPPINES, 13 May 1969, coll. F. Schwartz; USNM 217767 (1), SL 93 mm, same data as above; USNM 217770 (2), SL 120 mm, Macclesfield Bank, SOUTH CHINA SEA, R/V Cape St. Mary, Sta 17, 69.6–80.5 m, 13 Jun 1964, coll. W. L. Chan; USNM 217774 (1), SL 131 mm, Macclesfield Bank, SOUTH CHINA SEA, R/V Cape St. Mary, Sta 20, 78.7–80.5 m, 13 Jun 1964, coll. W. L. Chan; USNM 218936 (1), SL 124 mm, Visayan Sea, PHILIPPINES, 26 fms, 4 Jun 1978, coll. L. Knapp; USNM 218952 (6), SL 111–126 mm, Visayan Sea, PHILIPPINES, 38 fms, 5 Jun 1978, coll. L. Knapp; AMS I.20218-001 (5), SL 76-84 mm, ARAFURA SEA, Alpha Helix, 30 fms, 16 Mar 1975, coll. J. Paxton; AMS I.20751-014 (6); 44-126 mm, SL 44-126 mm, Lizard Island, AUSTRALIA, 0–25 m, prawn trawl, 2 Aug 1979, coll. B. Russell; AMS I.20752-018 (1) SL 131 mm, same data as above.

DIAGNOSIS AND COMPARISONS.—A species of Synodus with the following combination of characters: dorsal-fin rays (branched and unbranched) 13–14 (usually 14); anal-fin rays 9–10 (usually 9); pored lateral-line scales 55-57 (usually 55); transverse scale rows 3.5/5; vertebrae 54–56 (usually 55); combined dorsal and anal procurrent rays 24–31; anterior palatine teeth longest and in a discrete group; peritoneal spots 10–11; posterior pelvic process wide; prominent pigment spot at upper distal corner of operculum. For comparisons see S. hoshinonis.

DESCRIPTION (holotype plus range).—Dorsal-fin rays 13 (13–14); anal-fin rays 9 (9–10); pectoral-fin pectoral-fin rays 12; pelvic-fin rays 8; procurrent rays 30 (24–31), dorsal 15 (13–16), anal 15 (11–15); lateral line continuous, 55 (55–57) pored scales; scale rows above lateral line from dorsal origin 3.5; scale rows below lateral line to anal origin 5; predorsal scales 13 (13–15); rows of cheek scales 5 (4–5); vertebrae 54 (54–56); peritoneal spots 11 (10–11).

Percentages of Standard Length: Mean (range): head length 28.6 (27.1–30.3); snout length 6.4 (5.4–7.1); upper jaw length 17.3 (16.0–18.0); diameter of bony orbit 6.7 (5.6–8.0); least width of bony interorbital 3.2 (2.9–3.3); snout to dorsal origin 41.9 (40.2–44.0); snout to adipose origin 84.7 (82.3–87.7); snout to anal origin 76.6 (73.6–78.9); snout to pelvic insertion 35.4 (33.6–37.2); snout to pectoral insertion 27.2 (25.3–29.2); first-dorsal-ray length 10.5 (8.7–12.1); longest-dorsal-ray length 14.3 (13.5–15.1); pectoral-fin length 12.3 (11.6–13.0); pelvic-fin length 22.9 (21.8–24.3); dorsal-fin base 16.1(14.7–18.0); anal-fin base 9.3(8.9–10.0); based on 7 specimens 92.9 to 172.8 mm SL.

Body fusiform, head somewhat depressed, caudal region a little compressed. Large cycloid scales on body, cheeks, and operculum, postoral portion of cheeks scaly. Snout sharply pointed, broader than long; the anterior nostril on each side bearing a short, rounded process barely reaching anterior margin of nares when depressed anteriorly. Interorbital space concave, occipital region bony. Palatine teeth in an elongate V-shaped pad, teeth pointing backwardly, those in front largest and in a discrete group. Lingual teeth well developed, those on free end of tongue largest and about 40 in number. Teeth caniniform, larger teeth with arrow-shaped tips. Pectoral fins reaching a line from base of pelvic fins to origin of dorsal fin. Outer pelvic ray unbranched and short, fifth branched ray (sixth ray) longest. Posterior bony process of pelvic girdle broad. Peritoneum pale.

COLOR PATTERN.—As in S. hoshinonis.

DISTRIBUTION AND HABITAT.—Synodus tectus so far has only been collected from the western Pacific Ocean (South China Sea south to Great Barrier Reef). Depth of capture data for six collections indicate this species is found at moderate depths of 25 to 82 m (five collections over 50 m). The Queensland collection (Lizard Island) was made on a sand-weed bottom.

ETYMOLOGY.—The Latin tectus (disguised) alludes to its external similarity to S. hoshinonis.