Characteristics
Form elongate oval. Labrum and mandibles prominent, produced beyond apex of
clypeus, clypeus with or without horn. Antenna with 10 segments, antennal club
with 3 tomentose segments. Anterior coxae transverse. Pronotum with or without
horn-like lateral or anterior projections. Scutellum exposed. Metasternum longer
than abdominal sternites. Metatibia with apical spines separated by basal metatarsal
segment. Tarsal claws on all legs not independently movable, claws equal in
length or size. Onychium cylindrical with 2 setae. Pygidium exposed weakly beyond
apices of elytra.
Classification Status
The name Orphninae was erected by Erichson (1847). Paulian (1984) elevated the
Orphninae to family-level status and created a new subfamily, the Aegidiinae
for the New World taxa. We follow Lawrence & Newton (1995) and treat the
group as a subfamily of the family Scarabaeidae. The Orphninae resemble members
of the Hybosorinae based on the prominent mandibles and labrum, and Arrow (1911)
commented that the Orphninae share a pectinate tibial spur (which we have not
observed in New World taxa) with the Ochodaeidae. Scholtz &Chown (1995)
hypothesized that the Orphninae is a member of the Scarabaeidae and is basal
to the clade that includes the subfamilies Melolonthinae, Dynastinae, Rutelinae,
Cetoniinae, Trichiinae, and Valginae. Based on larval characters, Paulian &
Lumaret (1982) hypothesized that the Orphninae are intermediate between the
"laparostict" and "pleurostict" scarabs and show some convergences
with certain tribes of Melolonthinae. In a more recent phylogentic analysis
based on larval characters Grebennikov & Scholtz (2004) were not be able
to establish the phylogenetic relationships of the Orphninae. In their phylogeny,
Orphninae is part of a politomy that includes other Scarabaeidae subfamilies,
Lucanidae, Hybosoridae, Bolboceratids (considered as family), and Geotrupidae.
Preliminary phylogenetic analyses based on molecular data suggest that the Orphninae
are sister taxa to the Allidiostomatinae (Scarbaeidae) (Ocampo et al.
in prep.).
Distribution
The subfamily includes about 80 species worldwide (Arrow 1912, Paulian 1984).
The subfamily is divided into two tribes: the Aegidiini and the Orphnini. The
tribe Aegidiini is distributed in the New World and includes four genera. The
tribe Orphnini is distributed in the Old World and includes 10 genera (Arrow
1912).
New World Genera (click on species
names for more information)
Aegidium Westwood 1846
Includes 12 species (Paulian 1984) that occur from southern Mexico to Chile
and to the West Indies. Adults have been found feeding on decaying banana stems
in coffee-cacao plantations (Morón 1991). Adults have been collected
in flight intercept traps. The larva of one species, A. cribratum Bates, was
found under rotten logs and was described by Morón (1991). Keys to species:
Paulian 1984.
Aegidiellus Paulian 1984
A monotypic genus that includes A. alatus (Castelnau) from Rio de Janiero
in Brazil. Reference: Paulian 1984.
Aegidinus Arrow 1904
Includes three species from Colombia, Guyana, and Brazil. Key to species: Paulian
1984.
Paraegidium Vulcano, Pereira & Martinez 1966
A monotypic genus, including only P. costalimai Vulcano, Pereira &
Martinez, from eastern Brazil. Reference: Paulian 1984.
Ecology
Little is know of the ecology and biology of this small group of scarabs. In
the New World, adults are collected at low- to mid-elevations. They have been
observed on banana and cacao plantations on banana stems and have been collected
in flight intercept traps.
Larvae
Morón (1991) described the larva of Aegidium cribratum. It was
found under rotting logs.
References Cited
ARROW, G.J. 1911. XLVIII. On lamellicorn beetles belonging
to the subfamies Ochodaeinae, Orphninae, Hybosorinae, and Troginae. Annals and
Magazine of Natural History (series 8) 7: 390-397.
ARROW, G.J. 1912.
Scarabaeidae: Pachypodinae, Pleocominae, Aclopinae, Glaphyrinae, Ochodaeinae,
Orphninae, Idiostominae, Hybosorinae, Dynamopinae, Acanthocerinae, Troginae.
Coleopterorum Catalogus pars 43, W. Junk, Berlin. 66 pp.
ERICHSON, W. F. 1845-1847. Natureschichte der Insecten Deutschlands.
Erste Abtheilung, Coleoptera, Vol. 3: 1-800. Verlag der Nicolaischen Buchhandlung,
Berlin.
LAWRENCE, J. F. AND A. F. NEWTON, JR. 1995. Families and subfamilies
of Coleoptera (with selected genera, notes, and references and data on family-group
names), pp. 779-1006. In J. Pakaluk and S. A. Slipinski (eds.), Biology, Phylogeny,
and Classification of Coleoptera. Papers Celebrating the 80th Birthday of Roy
A. Crowson. Muzeum i Instytut Zoologii PAN, Warszawa, Poland.
MORON, M. A. 1991. Larva and pupa of Aegidium cribratum Bates
(Coleoptera: Scarabaeidae: Orphninae). Coleopterists Bulletin 45(4): 360-367.
PAULIAN, R. 1984. Les Orphnidae Americains (Coleopteres, Scarabaeoidea).
Annals Société Entomologique de France (N.S.) 20(1): 65-92.
PAULIAN, R. and J.-P. LUMARET. 1982. La larve des Orphnidae.
Bulletin de la Société Entomologique de France 87: 263-272.
SCHOLTZ, C. H. and S. L. CHOWN. 1995. The evolution of habitat
use and diet in the Scarabaeoidea: a phylogenetic approach, pp. 355-374. In
J. Pakaluk and S. A. Slipinski (eds.), Biology, Phylogeny, and Classification
of Coleoptera. Papers Celebrating the 80th Birthday of Roy A. Crowson. Muzeum
i Instytut Zoologii PAN, Warszawa, Poland.