In 1869, the genus
Letheobia was established by
Edward Drinker Cope based primarily on two specimens of
Letheobia pallida from
Zanzibar, but later also including
Letheobia caeca (originally
Onychocephalus cæcus Duméril, 1856) from
Gabon.
Wilhelm Peters, in 1874 when describing
Onychocephalus lumbriciformis from Zanzibar and in 1878
Typhlops unitaeniatus from Kenya, considered
Letheobia to be a
subgenus. Nonetheless, in 1881, Peters selected
Letheobia caeca Duméril as the type species for the genus. In 1883,
Boulenger decided that at best
Letheobia was a subgenus of
Typhlops, and placed it as a junior synonym. Later in reconstructing
Rhinotyphlops in 1974,
Roux-Estève moved all of
Letheobia species into
Rhinotyphlops, mostly into her Groups IV, V and VI. However, molecular studies in the 2000s showed that
Rhinotyphlops, as conceived by Roux-Estève (1974), was polyphyletic, and that many if not all of Groups V and VI constituted a separate genus, for which the name
Letheobia had priority. In 2007
Broadley and
Wallach formally revived the genus
Letheobia. In 2013, Pyron et al. considered with some certainty that
Letheobia was a sister group to the combined genera
Afrotyphlops and
Megatyphlops, while the three were then sister to
Rhinotyphlops, and the four were the sister to
Typhlops. ==Species==