Head scutellation characters are certainly useful for identifications based on external morphology. Liotyphlops fossorial, cryptozonic habits, and nocturnal activity.
Peters W (1881). "Einige herpetologische Mittheilungen. 1. Uebersicht der zu den Familien der Typhlopes und Stenostomi gehörigen Gattungen oder Untergattungen ". Sitzungberichte der Gesellschaft Naturforschender Freunde zu Berlin1881 (4): 69–71. (Liotyphlops, new genus, p. 69). (in German).
Freiberg M (1882). Snakes of South America. Hong Kong: T.F.H. Publications. 189 pp. ISBN0-87666-912-7. (Genus Liotyphlops, pp. 84, 86 + drawing of head scalation on p. 84).
Goin CJ, Goin OB, Zug GR (1978). Introduction to Herpetology, Third Edition. San Francisco: W.H. Freeman. xi + 378 pp. ISBN0-7167-0020-4. (Genus Liotyphlops, p. 311).