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Odontotaenius disjunctus (Horned Passalus)

Order: Coleoptera
Family: Passalidae
Genus: Odontotaenius

The horned passalus or patent-leather beetle, Odonotaenius disjunctus, is a type of bess beetle in the family Passalidae and one of the most delightful discoveries one can make upon overturning logs (Evans 2014). These beetles are found in the woodlands of the eastern Canada and the United States (Evans 2014). They are typically dark reddish brown or black with a shiny elongated abdomen, and have a wide head with an impressive horn (Evans 2014). Their body segments and legs are trimmed with golden hairs (Bibbs et al. 2010) and they rely on their robust mandibles to tear apart and macerate the rotting wood upon which they feeds (White 1983). The horned passalus is an unusually communicative beetle (Bibs et al. 2010). They produce seventeen distinct sounds created by stridulation, rubbing their wings against each other to create a shrill squeaking (Bibbs et al. 2010). These noises serve as both social communication and anti-predator defense (Bibbs et al. 2010). Adult horned passalids are devoted parents, defending ideal nesting sites and pre-chewing wood pulp for the larvae (Bibbs et al. 2010; White 1983). Pair rearing of larvae, a reluctance to fly, and a docile nature make this beetle an excellent specimen for education or a children’s pet (Bibbs et al. 2010).

Odontotaenius disjunctus - full view of body.

Odontotaenius disjunctus (Horned Passalus Beetle)

Odontotaenius disjunctus - Close up of head.

Odontotaenius disjunctus – Close up of head.

Odontotaenius disjunctus - View of highly sclerotized forewing.

Odontotaenius disjunctus – View of highly sclerotized forewing.


Horned Passalus Stridulation at
Bess Beetle Care Guide
Hordned Passalus on Wikipedia


(1) Bibbs, C., Hodges, A., & Baldwin, R. (2010). Horned passalus – Odontotaenius disjunctus (Illiger). Retrieved December 7, 2015, from
(2) Evans, A. (2013). Bess Beetles (Passalidae). In Beetles of eastern North America. Princeton, New Jersey: Princeton University Press.
(3) White, R. (1983). A field guide to the beetles of North America. Boston: Houghton Mifflin.