Ctenostoma (Coleoptera, Cicindelidae): Révision du Genre et Descriptions de Nouveaux Taxons [Ctenostoma: Revision of the Genus and Descriptions of New Taxa]

Because of the paucity of specimens in collections and the scarcity of credible data from historical and current research, the beetle genus Ctenostoma remains one of the most poorly known of the family Cicindelidae. The identification of many if not most specimens is almost hopelessly confused and unreliable. For this reason, the author decided to revise the genus. He began by firmly establishing the characters of all previously described species with a complete redescription of each type specimen, including an illustration of dorsal and lateral views as well as details of diagnostic characters such as labrum, aedeagus, vertex and palpi.

He then developed a new classification within the genus that is fundamentally similar to the preceding ones but more complete, so that the stability of the nomenclature could be maintained as far as possible. The single genus Ctenostoma is preserved but divided into eight subgenera as follows: Procephalus Castelnau, Neoprocephalus nov., Microprocephalus nov., Ctenostoma (s.str.) Klug, Euctenostoma nov., Myrmecilla Lacordaire (sensu novo), Paractenostoma nov., Salvioides nov. To distinguish these subgenera, the author used four fundamental characters primarily associated with the mouth: the shape of the second joint of maxillary palpi, the shapes of last joint of labial palpi, labrum and mandibles. Some other important characters are also used, such as the shape of the body, elytral sculpture and pilosity.

At the species-group level, several other important characters are used: the size, the shapes of head, vertex and temples, pronotum, elytral apex and elytral sculpture, again the characters associated with the mouth. In addition, the following characters are included: colour of antennae, elytral pattern, shape of posterior legs and the shape of the aedeagus and the pilosity. Closely allied species are combined in groups.

The present total number of taxa is 121 of which 107 are bona species, while 14 are treated as subspecies. Of the 80 previously proposed names (described taxa or only in litteris), 65 are recognized as valid. A total of 56 new species-group taxa are described in this paper. They are: nigrum lecourti, onorei, onorei colombiensis, arnaudi, longipalpe, aeneum, simile, ecuadorensis, maculosum, erwini, spinosum, ornatum werneri, cayennensis, pearsoni, durantoni, davidsoni, cylindratum, brunneum, cassolai, deuvei, intermedium, ibidion jolyi, nitidum, tumidum, wappesi, brendelli, turnbowi, johnsoni, pusillum, pusillum minimum, guyanensis, acciavattii, bahiaensis, transversum, bifasciatum horni, rapillyi, wiesneri, sumlini, inca, regium, magnum, vicinum, zerchei, rivalieri, flexuosum, ichneumoneum ellipticum, coracinum, abbreviatum, pygmaeum concolor, infimum, parvulum, agnatum fuscum, luteum, compactum, modicum, and parallelum.

The status of numerous taxa are modified as follows:
- 10 taxa, considered as subspecies in the most recent classification (WIESNER, 1992), are treated as species: metallicum sallei Chaudoir, metallicum insigne Chaudoir, metallicum nigrum Chaudoir, ebeninum subtilesculptum Horn, heydeni rugiferum (Horn), batesi rugicolle Horn, rugosum klugeanum Horn, rugosum bifasciatum Dejean, unifasciatum gautardi Chaudoir, ichneumoneum breviusculum Mannerheim;
- 2 taxa, formerly considered to species rank, are treated as subspecies: schmalzi paraguayensis van Nidek, schaumi pilosulum Horn;
- 2 new synonymies are proposed: gounellei Horn = chaudoiri Horn; rectofasciatum Horn = formicarium (Fabricius);
- 1 new combination is proposed: heydeni pseudoheydeni Horn becomes rugiferum pseudoheydeni;
- 3 taxa, formerly considered as synonymous, are rehabilitated to species rank: ibidion Dohm, landolti Steinheil, hirsutum Horn;
- 2 following names, being hornonymous, are not valid: formicarium Klug, trinotatum Klug;
- 29 specimens labelled syntype, or sometimes type, are designated as lectotype in accordance with the original descriptions; it is the case for: insigne Chaudoir, nigrum Chaudoir, sallei Chaudoir, ornatum Klug, subtilesculptum Horn, maculicorne (Chevrolat), sigma Bates, laeticolor Bates, ibidion Dohm, angustoobliquatum Horn, gounellei Horn, succinctum (Castelnau), batesi Chaudoir, rugicolle Hom, rugosum Klug, bifasciatum Dejean, sahlbergi Chaudoir, luctuosum Chaudoir, laceratum Sahlberg, schmalzi Horn, bicristatum Chaudoir, asperulum Bates, globifions Horn, ichneumoneum Dejean, interruptum Chaudoir, agnatum Chaudoir, crucifrons Horn, obliquatum Chaudoir, zikani Horn;
- the type of dormeri Horn being definitely lost, it was necessary to designate a neotype;
- keys for subgenera and for groups of taxa are supplied.