Orange-Striped Emperor

Lethrinus obsoletus, commonly known as the orange-striped emperor, yellow-banded emperor, or yellowstripe emperor, is a marine ray-finned fish within the family Lethrinidae. This species exhibits a broad distribution across the Indo-Pacific region.

Originally described as Sciaena obsoleta by the naturalist Peter Forsskål in 1775, the species was included in a publication edited by Carsten Niebuhr. Although no specific type locality was designated, it is presumed to be the 🌊 Red Sea. There is some debate among taxonomists regarding the classification of the genus Lethrinus, with certain authorities suggesting the existence of a monotypic subfamily, Lethrininae, separate from Monotaxinae, where other genera in Lethrinidae are placed. However, the 5th edition of Fishes of the World does not recognize these subfamilies as valid and classifies the family Lethrinidae under the order Spariformes.

The species name obsoletus means "worn out" or "decayed," possibly referring to the faint yellow-purple stripe, which was historically described as "orange-yellow." Morphologically, Lethrinus obsoletus is characterized by a dorsal fin supported by 10 spines and 9 soft rays, and an anal fin with 2 spines and 8 soft rays. The body displays a moderately deep profile, fitting 2.4 to 2.8 times into the standard length. The head's dorsal profile around the eye is straight or slightly convex, with similar features on the snout. The jaw teeth are rounded or conical, and the pectoral fin's axilla is densely scaled. Its coloration ranges from light tan to olive-brown, featuring a horizontal yellow-orange stripe along the lower flank and indistinct vertical bands on the head. Lethrinus obsoletus can reach a maximum total length of 60 cm (24 in), although 30 cm (12 in) is more common.

The orange-striped emperor inhabits the 🇮🇳 Indian and Western 🌊 Pacific Oceans, from the 🌊 Red Sea and eastern Africa to areas including the Ryukyu Islands (🇯🇵 Japan), 🇹🇴 Tonga, and 🇼🇸 Samoa. Its presence extends to various 🇦🇺 Australian marine locations such as the Rowley Shoals and the northern Great Barrier Reef. The species favors seagrass beds and regions with sand and rubble in lagoons and reefs, with juveniles predominantly occupying seagrass beds and adults transitioning to reef environments. They are found at depths up to 30 meters (98 feet).

Dietarily, Lethrinus obsoletus primarily consumes crustaceans, molluscs, and echinoderms. It exhibits protogynous hermaphroditism, with spawning activities in Palau occurring from November to April, typically on the last five days of the lunar month.