Latin name

Bothus myriaster

Other name

Bothus myriaster

Identification

The body of the Indo-Pacific oval flounder is oval, strongly compressed.  Caudal peduncle narrow, much more than one-third the length of the head. Head small, much less than one-third the length of the body. Muzzle small, equal to or shorter than the diameter of the eye. Eyes large, equal in length to the maxilla, separated by a wide concave space; the lower eye more or less in front of the upper. The body is nearly round in young individuals, becoming ovoid with growth. 

The nostrils on the ocular side of the head are located near the upper margin of the lower eye; the anterior nostril is tubular, with a long valve on the posterior margin, the posterior nostril is without valve or tube. The nostrils on the blind side of the head are located below the base of the dorsal fin, tubular, anterior nostril with a long valve on the posterior margin. 

The mouth is small, its anterior part almost horizontal; it descends below the lower margin of the lower eye, coming slightly behind the anterior margin of this eye. The teeth on the upper jaw are in two rows, the outer row being much stronger and more widely spaced than the inner row. On the lower jaw they are double rowed at the anterior end and single rowed at the posterior end. 

The gill stamens on the first arch are small, with a pointed tip, without serrations on the posterior margin; on the upper half they are rudimentary or absent. 

Scales very fine, cycloid on ocular side of body except for bands along bases of dorsal and anal fins covered with ctenoid scales, all scales cycloid on blind side of body. Snout, both jaws, head margin anterior to interorbital space, and pectoral fins without scales. 

The lateral line on the ocular side of the body forms a small arc above the base of the pectoral fin. The lateral line is not visible on the blind side of the body. 

Features of fish fins

Dorsal spines (total): 0; Dorsal soft rays (total): 87 - 97; Anal spines: 0; Anal soft rays: 61 - 73. 

All rays in the dorsal, anal, pectoral, and ventral fins are unbranched. Pectoral fins asymmetrical, on the eye side of the body the fin is considerably elongated. The pelvic fin of the eye side of the body is located below the center of the lower eye or slightly forward; its fourth ray is opposite the first ray of the pelvic fin of the blind side of the body. The caudal fin is rounded along the posterior edge, its inner 13 rays are branched, the rest are simple. 

Fish colouring

The general coloration of the ocular side of the body is pale brown or greenish, with numerous dark brown spots surrounded by pale brown rings; an indistinct dark ocular spot smaller than the eye is located at the transition of the arc of the lateral line to the straight part; a second well-marked dark spot is located in the middle of the straight part of the lateral line. The dorsal and anal fins are paler than the body, with numerous small dark brown spots scattered throughout. Pectoral fin with pale brown spots forming about 8 transverse thin stripes. The last quarter of the caudal fin is dark. The blind side of the body is yellowish-white at the front, becoming dark brown towards the caudal fin. There are stripes between these light and dark areas.

Distribution

Widespread in the Indo-West Pacific: definitely recorded in Inhambane, Mozambique; throughout the Indian Ocean to Java, Sumatra, Vietnam, Philippines, Taiwan, South Korea, Japan and Lord Howe Island.

Habitat

Tropical marine demersal species. Habitat depth range from 10 to 155 m.

Size

The maximum length of fish of this species is 27.0 cm. The body height of these fish is less than half the length.

Behavior

Rare species. Occupies sandy and muddy areas of the continental shelf.  

Food and feeding habits

The Indo-Pacific oval flounder feeds on benthic invertebrates.

Reproduction

The species is characterized by considerable sexual dimorphism. Most of the sexually dimorphic characters develop at a body length of about 8 cm. In males, the pectoral fin on the ocular side of the body is considerably elongated, far exceeding the length of the head (0.39-0.67 times its length). Its middle rays are filiform, almost half free of the fin membrane. The interorbital space is exceptionally wide, 2.07-3.00 times the length of the head. There are strong spines on the snout, on the symphysis of the lower jaw, and in some small individuals on the edges of the orbit around the eye. Each eye has a large leathery lobe at the back of the eye. The dark part of the blind side of the body, anteriorly to the end of the pectoral fin, is darker and has a greater number of transverse dark bands. In females, the pectoral fin is thinner but shorter than in males, 0.57-0.88 times the length of the head. Interorbital space narrow (2.73-3.76 times head length). No spines on snout, symphysis of mandibles, rims of orbits. No leathery lobes on eyes. Part of blind side of body with dark coloration paler, noticeably smaller and with fewer stripes than in males.

Fishing

This species is commercially important for fishing. 

Relationship with a person

Harmless. This fish is sold fresh or used to make fishmeal.