Form elongate oval. Labrum and mandibles produced beyond apex of clypeus. Antenna
with 10 segments, antennal club with 3 tomentose segments. Anterior coxae transverse.
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 not exposed
beyond apex of fifth taromere, bisetose. Pygidium exposed beyond apices of elytra.
Arrow (1904) erected the subfamily Idiostominae for species that were previously
placed in the genera Phyllognathus (Dynastinae), Oryctes (Dynastinae),
and Orphnus (Orphninae). Arrow (1904) transferred species from these
disparate groups into the genus Idiostoma Arrow. Because this name was preoccupied,
Arrow (1940) proposed Allidiostoma as the replacement name for the
genus and Allidiostomidae as the replacement name for the family (elevating
the group from subfamily to family status). Lawrence and Newton (1995) amended
the name to reflect the correct stem to Allidiostomatinae. No studies have commented
on the relationships of this subfamily, although preliminary phylogenetic analysis
based on molecular data indicates that the group is the sister taxon of the
Orphninae (Ocampo et al in prep.).
This small subfamily includes one genus and 7 species. The group is resticted
to southern South America. Allidiostomines superficially resembles members of
the Dynastinae and some members of the subfamily were originally placed in such
genera as Oryctes and Phyllognathus.
New World Genus of Allidiostomatinae
Allidiostoma Arrow 1940
Includes six species (Arrow 1912) that occur in Argentina, Chile, Peru, and
Nothing is known of the ecology and biology of this small group of scarabs.
Arrow (1904) reported that A. rufum (Arrow) possesses a stridulatory file on
the inner face of the hind coxa.
Larvae. Larvae are not
know for the group.
ARROW, G. J. 1904. Sound-production in the lamellicorn beetles.
Transactions of the Entomological Society of London 1904: 709-750.
ARROW, G. J. 1909. XV. On the characters and relationships
of the less-known groups of Lamellicorn Coleoptera, with descriptions of new
species of Hybosorinae, etc. Transactions of the Entomological Society of London
ARROW, G. J. 1912. Scarabaeidae: Pachypodinae, Pleocominae,
Aclopinae, Glaphyrinae, Ochodaeinae, Orphninae, Idiostominae, Hybosorinae, Dynamopinae,
Acanthocerinae, Troginae. Coleopterorum Catalogus pars 43, W. Junk, Berlin.
ARROW, G. J. 1940. A nomenclatural note (Coleopt.). Proceedings
of the Entomological Society of London (B) 9(1): 16.
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.
RUIZ, F. 1924. El genero Idiostoma en Chile. Revista Chilena
de Historia Natural 1924: 99-101.