Psomus Casey, 1892: 458

Anzaldo, Salvatore S., 2017, Review of the genera of Conoderinae (Coleoptera, Curculionidae) from North America, Central America, and the Caribbean, ZooKeys 683, pp. 51-138 : 83-85

Psomus Casey, 1892: 458 Fig. 91

Type species.

Psomus politus Casey, 1892 [by monotypy] (= Orchestes armatus Dietz, 1891).

Gender.

Masculine.

Diagnosis.

The combination of concealed pygidium, appendiculate tarsal claws, and sulcate subapical pronotal constriction readily distinguishes Psomus from the other genera treated here. Philides is the only other genus without simple tarsal claws and Peltophorus and Zygops have a sulcate subapical pronotal constriction, but each of those three genera have an exposed pygidium (which Psomus does not) and are otherwise distinct in habitus. Psomus is unique among the lechriopine genera for having a flattened mesoventrite and Type II sclerolepidia (Type II sclerolepidia also known from Copturus , Microzurus , and Euzurus , though each has a modified mesoventrite) although this combination is also found in Lissoderes , which is currently a zygopine ( Lyal et al. 2006: 229); neither of those genera seem very well placed in their current tribes.

Some observed species have a ventrally expanded first abdominal ventrite and modifications to the profemora and tibiae that are similar to what is found in some Cleogonini ( Prena and Whitehead 2012: 57). These differences were not mentioned by Champion when describing three Central American species, but he considered his species as "perfectly congeneric with P. politus , Casey [= P. armatus (Dietz)]" ( Champion 1906b: 128). In addition to the characters given above distinguishing the genus, the species of Psomus have a second funicular article that is about equal to the first and a tibial apex with an uncus at the posterior apical angle or the middle of the apex.

Phylogenetic relationships.

The appendiculate tarsal claws (shared only with Philides ) and a deep subapical pronotal constriction (shared only with Zygops and Peltophorus ) are easily observed characters but not particularly suggestive of a relationship. The single U.S. species, P. armatus (Dietz, 1891) was originally described in the genus Orchestes Illiger, 1798 ( Curculioninae : Rhamphini ). Psomus bears a resemblance to the cleogonine Isotrachelus (which was previously placed in the Old World conoderine tribe Lobotrachelini Lacordaire, 1865), but differs from Isotrachelus by the insertion of the antenna on the rostrum, which in Psomus is in the basal half of the rostrum, and the tarsal claws, which in Isotrachelus are simple.

Host associations.

Psomus armatus can be found on ash trees ( Oleaceae Hoffmanns. & Link: Fraxinus L.) ( Sleeper 1963). Hosts of the Central American species are unknown.

Described species.

Four.

Range.

Eastern Canada and U.S.A., Guatemala, Panama.

Figures

Figures 91 - 94. Lateral and dorsal habitus images of Lechriopini and Zygopini. All scale bars = 1 mm unless otherwise specified. 91 a-b Psomus armatus [ARTSYS 0000533] 92 a-b Turcopus viscivorus [ARTSYS 000530]; scale bar = 2 mm 93 a-b Arachnomorpha circumlineata [ARTSYS 0000535] 94 a-b Archocopturus laselvaensis [ASUHIC 0086633].