Type species. Anachis subturritus Carpenter, 1864. Northeast Pacific. Included species. Type species and Aesopus osborni Hertlein & Strong, 1951, from southern Mexico, which is smaller and more slender.
Etymology. Named as a taxon that has been removed from Aesopus. Gender masculine.
Diagnosis. Shell small, 3-5 mm long with about four teleoconch whorls. Shell narrow with moderately incised sutures, with the primary sculpture consisting of pronounced axial ridges overall. Aperture semilunate, with no denticles or notable thickening of the labial edge.
Remarks. The type species has been variously and inconsistently assigned to a genus by previous authors. It was retained by Palmer (1958) in Anachis. Keen (1971: 576) placed the type species in Aesopus Gould, 1860, subgenus Ithiaesopus Olsson & Harbison, 1953, from which Exaesopus subturritus differs in having a shorter aperture, a more impressed suture and much fewer, broader and stronger axial ribs than the thin lamellar axials of Ithiaesopus. An affinity between Aesopus, in which there is fine spiral sculpture only, and Ithiaesopus in which there is fine axial sculpture, is evident, based on shell shape, but Exaesopus, with its lack of a descending suture, deeper suture and strong axial sculpture, is not morphologically similar to either genus.