How to identify the oriental red-fin dolphin

morphological characteristics

Dorsal fin 17; gluteal fin 15; pectoral fin 17-18; caudal fin 10(8 branches). Body length 135-515mm. The body is long, and the head and chest are thick and rounded to taper backward. The caudal shank is conical; There is a longitudinal skin edge below the head body; The body length is 1.9-3.5 times the body height, which is 1.8-2.9 times the head length. The posterior half of the head resembles a square; the length of the head is 2.2-2.5 times the length of the kiss, 6.4-8.2 times the diameter of the eye, and 1.8-2 times the distance between the eyes. The kiss is blunt and round, approximately equal to the length of the head behind the eye. Eyes slightly smaller, laterally superior. Two nostrils nasal sac protrusion on both sides. Small mouth, front position. Lips developed. The upper and lower jaws and teeth are four large teeth. Gill hole lateral median, short transverse moon. No scales; except for the kiss, both sides of the head and the tail, there are small thorns. The lateral line is median in the proximal part of the caudal stalk, and is gradually higher forward. There are nape branches, lateral branches of the head, upper and lower branches of the eyes and dorsal branches of the nose to the head. There are ventral branches below the posterior half of the body and mandibular branches on the lower side of the head.

Dorsal fin knife-shaped, posterior superior margin of anus. The gluteal fin is similar to the dorsal fin but slightly posterior. pectoral fin lateral median, subsectored. Caudal fin rounded and truncated. Dorsal black, ventral white, along the ventral edge of brilliant yellow; pectoral fin after the upper body side has a white margin of eye-like large black spots, and then to the tail there are several small black spots. Dorsal and caudal fins black; pectoral fins grayish brown; gluteal fins reddish yellow, redder at base.