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Tribe Pentodontini

Scarab - Orizabus pyriformis Euetheola humilis Black beetle - sugar cane beetle? - Euetheola humilis Scarab - Tomarus gibbosus beetle - Tomarus Phyllophaga - Tomarus Another Beetle sp. - Euetheola humilis Tomarus gibbosus
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Suborder Polyphaga (Water, Rove, Scarab, Long-horned, Leaf and Snout Beetles)
Superfamily Scarabaeoidea (Scarab, Stag and Bess Beetles)
Family Scarabaeidae (Scarab Beetles)
Subfamily Dynastinae (Rhinoceros Beetles)
Tribe Pentodontini
Numbers
Aphonides Rivers 1889, single sp. [A. dunnianus (Rivers 1889) (Anoplognatho) - Texas, Arizona]
Aphonus LeConte 1856, 6 spp., east of rocky mountains
Coscinocephalus Prell 1936, 1 sp. [C. cribrifrons (Schaeffer 1906) (Anoplocephalus) - SW]
Euetheola Bates 1888, 2 spp., general
Orizabus Fairmaire 1878, 3 spp., west
Oxygrylius Casey 1915, 2 spp., SW O. ruginasus and O. peninsularis - California
Tomarus Erichson 1847, 8 spp., general, mostly eastern
Identification
Members of this tribe can be characterized by apical edge of the posterior tibia truncate. Males and females similar in appearance [sexual dimorphism absent].


Key to the tribe Pentodontini. One error noticed; couplet 11- range of genus Aphonus should be "United States east of the Rocky Mountains".

Key to the Genera of New World Pentodontini (after Ratcliffe & Hardy 2005)

1. Antenna with 9 segments (Head lacking horns, instead with a transverse carina. Apical
region of pronotum not declivous. SW United States) .............. Aphonides Rivers 1889
1’. Antenna with 10 segments ......................................................... 2

2(1). Small species, generally less than 15 mm in length. Head lacking carina, tubercles,
or horn (rarely with a trace of tubercles). Pronotum lacking tubercles or fovea. Posterior
tibia strongly broadened towards apex. Color black Pronotum completely and distinctly
punctate. Propygidium lacks stridulatory striae. Southern United States through South
America ................................................... Euetheola Bates 1888
2’. Larger species, generally greater than 15 mm in length. Head with transverse
carina (on subapex of clypeus or frontoclypeal suture), tubercles, or horn. Pronotum
usually with tubercles (rarely obsolete in Aphonus, some Tomarus) and usually with a
fovea or sulcus behind tubercles. Posterior tibia not strongly broadened
apically ............................................................................. 3

3(2). Clypeal apex acute, unidentate (Mandibles large, tridentate.) SW United States, N.
Mexico .......................................... Oxygrylius Casey 1915
3’. Clypeal apex bidentate, truncate, or rounded ..................................... 4

4(3’). High, transverse carina present immediately behind apex of clypeus ............ 5
4’. Transverse carina absent immediately behind apex of clypeus ...................... 6

5(4). Transverse carina (usually tridentate) just behind apex of clypeus. Pronotum
without tubercles. Size generally less than 17 mm. United States east of the
Rocky Mountains ................................................... Aphonus LeConte 1856
5’. Transverse carina just behind apex of clypeus entire or bidentate. Pronotum
tuberculate or not. Size generally greater than 17 mm. Central and SW United
States, Mexico, Guatemala, El Salvador, Nicaragua, Honduras ..... Orizabus Fairmaire 1878

6(4). Clypeus strongly narrowed toward apex, apex narrowly bidentate. Color
castaneous to black. Canada to Chile .............................. Tomarus Erichson 1847
6’. Clypeus not strongly narrowed toward apex, apex broadly truncate. Color fulvous to
rufocastaneous – Clypeus with apex strongly emarginate, reflexed, apical rim thin. Center
of head slightly tumid. Prosternal process long, columnar. SW United States, N.
Mexico ........................................................ Coscinocephalus Prell 1936