Diagnosis: It differs from its congeners with its thin, elongate body, slender, acute head with relatively long, projecting upper lip. Gill slit very small 16.3 in HL. Pelvic fin absent. Total of 2 cephalic pores on each side of head, 1 postocular pore and 1 anterior nasal pore. Lacrymal and posterior nasal pores absent. Vertebrae total 68, precaudal 22; last epineural on the 26th vertebra. Caudal rays 4-5. Tail length long. Dorsal origin anterior to the anus. Long but very low dorsal fin, almost non-existent anal fin, and unique black and white barred coloration. It is similar to both A. parvula and A. occidentalis, differing in coloration, its apparent lack of transparency of the body, and different vertebral features (Ref. 56640).