Morphological. The genus Rhabdoscelus can be identified through morphological characteristics. Key characteristics include: mesocoxae separated by more than the width of a mesocoxa, spotted or blotched elytra, pile raised in irregular vittae and pustules, and moderately large elytral strial punctures (Zimmerman, 1993).
Brodel (2013a) provides important morphological characters of Dryophthoridae, showing how to differentiate this family from Curculionidae.
A Dryophthoridae key by Zimmerman (1968) as modified by C. F. Brodel (2013) is found in Brodel (2013b).
A key to domestic and PPQ-intercepted genera of Dryophthorinae can be found in Brodel (2002). This key includes several genera of importance, including Metamasius, Rhabdoscelus, and Rhynchophorus.
Rhabdoscelus obscurus resembles in shape, size, and coloration other sugarcane- and palm-attacking dryophthorid weevils distributed throughout the Americas and Southeast Asia. See the CPHST Pest Datasheet for a detailed list.