Other Common Names
Peg Beetles, Betsy Beetles, Patent Leather Beetles
Explanation of Names
Author of family is Leach, 1815. Family name is from Greek
passalos, meaning a peg or gag, originally bestowed by
Fabricius (1).
Numbers
Two genera and four species in North America (
Univ. Florida,
Nearctica.com)
However, only two species, both in genus Odontotaenius, are currently known to occur in the United States--the other two species are doubtfully (or formerly?) known from Arizona (Schuster, 1994).
Worldwide, about 500 species are known (Schuster, 2001).
Identification
Large dark beetles with characteristic body form and lifestyle:
robust body, distinct gap between pronotum and elytra
pronotum grooved in middle
elytra deeply grooved
mandibles robust, toothed, project beyond tip of labrum
antennae not elbowed (geniculate) like those of the
Lucanidae, but they are curved when relaxed
antennae have 10 segements, including a club of 3 (typically) to 6 segments
antennal plates (lamellae) cannot be pressed together as in
Scarabaeidae and related families.
mentum (lower mouthpart) deeply notched, the notch occupied by the large, horn-like ligula, see Dillon, fig. 438
(2)
Each tarsus has five segments (tarsal formula 5-5-5)
Some images of the widespread Horned Passalus, Odontotaenius disjunctus, illustrating these characters:
Tarsi:
Range
Eastern and south-central North America. The Horned Passalus,
Odontotaenius disjunctus is widespread in east.
Odontotaenius floridanus is a Florida endemic, described in 1994. These are apparently the only two species of the family known to occur in North America (United States and Canada).
Family is cosmopolitan, with most species in the tropics.
Habitat
Live inside rotting logs in forests.
Food
Adults and larvae feed on wood
Life Cycle
Unique subsocial lifestyle. Adults and larvae live together in family groups in galleries excavated in rotting wood by adults. Adults care for larvae, and actively feed them prechewed food. Both adults and larvae stridulate, which is used for communication within the group. See Generic Guide to New World Scarab Beetles for more details.
Print References
The Century Dictionary--entry for
passalus (1)
America Beetles, Vol. 2, Chapter 25
(3)
Schuster, 1994. Odontotaenius floridanus New Species (Coleoptera: Passalidae): A Second U.S. Passalid Beetle.
Florida Entomologist 77(4): 474-478, available
here.
