Redescription of Opistognathus liturus, a Senior Synonym of O. cryos (Teleostei: Opistognathidae)

Abstract

The poorly known jawfish Opistognathus liturus Smith-Vaniz and Yoshino, 1985 is redescribed based on nine Japanese specimens (39.2–63.6 mm in standard length). The species can be distinguished from other members of the genus by the following combination of characters: posterior end of upper jaw rigid, without flexible lamina; dorsal-fin rays XI, 11 or XII, 11 (usually XI, 11); anal-fin rays II, 10; gill rakers 9–11 + 22–25 = 32–36; longitudinal scale rows 45–55; vertebrae 10 + 16 = 36; supraneural spines 2; lateral line terminating below 3rd or 4th soft ray of dorsal fin; upper two (rarely three) preopercular pore positions each with 2 or 3 pores; no scales above lateral line on side of nape to below base of last dorsal-fin spine; pectoral-fin base usually naked; small, roughly circular white (usually indistinct in fresh material but always clearly visible in life) and dark blotches scattered separately over entire head region (except ventral surface), including 3 or 4 dark blotches surrounding orbital ridge (except anteriorly and dorsally), and 1 dark blotch toward posterodorsal part of maxilla; no distinct large dark blotch on nape; body with yellowish to orangish-brown and whitish-brown mottles; 3 or 4 relatively wide, dark, wavy stripes (width similar to scale height) on lateral surface of body; dorsal fin generally bright yellow, with 5–9 dark circular to oblong blotches aligned along entire dorsal-fin base, dorsal margin of each blotch with strong pale white edge; anal, caudal, and pelvic fins bright yellow; and pale white and dark barred pattern on anterocentral part of caudal fin. In addition, “Opistognathus sp. 1” and Opistognathus cryos Su and Ho, 2024 are regarded as conspecific, the latter being treated as a junior synonym of O. liturus.