Acrochordonichthys gyrinus Vidthayanon & Ng 2003

Identification: Acrochordonichthys gyrinus has a moderately depressed body, a wide head, a slender caudal peduncle, a thick humeral process (maximum width = 16% length), a straight anterior margin on the anal fin, a straight posterior margin on the adipose fin, and a concave posterior margin on the pectoral fin. The head is covered with small, indistinct tubercles. Tubercles on the body are arranged in 5-6 horizontal rows on each side. The dorsal surface of the head and body is brown. Dark brown spots are randomly scattered on the dorsal surface of the head. The belly, chest and ventral surface of the head are cream-colored and lack spots. The dorsal, pectoral, pelvic and anal fins are cream-colored with 2 dark brown bands; one band occurs at the fin base and the other near the edge. The cream-colored caudal fin has a dark brown band near the edge and a dark brown patch at the base of the caudal peduncle. The cream-colored barbels and pectoral spines have dark brown spots on the dorsal surfaces. The premaxillary toothband is exposed when the mouth is closed. The pectoral spine has 6 serrations on the posterior edge. There are five branchiostegal rays and 39 vertebrae.

Range: This species is found in the Yom River in Thailand.

Habitat: A. gyrinus inhabits moderately strong currents in rivers with a mixed sand and mud substrate.

Similar species: A. ischnosoma, A. guttatus, A. mahakamensis, A. septentrionalis and A. strigosus have a straight posterior margin on the pectoral fin. A. ischnosoma has a longer dorsal-to-adipose fin distance. A. guttatus has a deeper body and a thinner humeral process. A. mahakamensis and A. strigosus have a rounded posterior margin on the adipose fin. A. septentrionalis has a deeper head.

Information from Vidthayanon, C. and H. H. Ng. 2003. Acrochordonichthys gyrinus, a new species of akysid catfish (Teleostei: Siluriformes) from Thailand. Zootaxa 183: 1-7.