Homothermon Ohaus, 1898

Moore, Matthew R., Jameson, Mary L., Garner, Beulah H., Audibert, Cedric, Smith, Andrew B. T. & Seidel, Matthias, 2017, Synopsis of the pelidnotine scarabs (Coleoptera, Scarabaeidae, Rutelinae, Rutelini) and annotated catalog of the species and subspecies, ZooKeys 666, pp. 1-349 : 1

Homothermon Ohaus, 1898 Figs 34 , 35

Type species.

Homothermon bugre Ohaus, 1898.

Species.

4 species; length 9-19 mm.

The genus Homothermon includes four uncommon species that are distributed in the Paulista center of endemism in Brazil and Argentina (Rio de Janeiro in the north to Santa Catarina, Rio Grande do Sul, and Misiones in the south) ( Müller 1973). Species in the genus are characterized by greatly enlarged metatibia in the male, claws on all legs simple (both male and female), male with a medial tubercle on the protarsal claw, pronotal basal bead incomplete anterior to the scutellum, elytral margin without a bead (=rounded), scutellum that is nearly twice as wide as long, clypeus semi-circular or subtrapezoidal, apex of mandibles bidentate, and parameres with a well-developed ventral plate.

Classification and nomenclatural history of members of the genus has been confused. Ohaus (1898) postulated that the genus was closely related to Thyridium Burmeister and placed it in the subtribe Anticheirina . Bates (1904) omitted the genus Homothermon (even though it was described six years prior to his revision) and also overlooked Homothermon praemorsus (Burmeister) (then classified as Strigidia praemorsus ) even though he treated Strigidia as a valid genus. In the Coleopterorum Catalogus ( Ohaus 1898, 1918), the genus was placed in the subtribe Pelidnotina . Soula (2008) commented that the genus “approaches” Pelidnota . Based on the elytral margin that lacks a bead, it is possible that the genus may be allied with Plesiorutela Jameson ( Rutelini ). Future research should examine the relationships of Homothermon , placing it within a broad context of Rutelini .

Homothermon serrano Ohaus and H. bugre are apparently sympatric. Based on our examination of specimens (including type specimens), the two species differ only in color but are conspecific in all other respects. Soula (2008) maintained H. serrano and H. bugre as separate species, and he stated that these are "good examples of two populations where the aedeagus is very similar, however the populations represent two good species that are sympatric" ( Soula 2008: 31; translated from French). Lacking additional character evidence, we think that this is open to interpretation.

Natural history for the genus is unknown. Homothermon serrano is known from the forested mountains near Theresopolis, Santa Catarina, Brazil ( Ohaus 1898).

Figures

Figure 34. Homothermon paulista Ohaus (valid name H. praemorsus Burmeister) type male (see " Type specimens and lectotype designation " in Methods) from ZMHB. A Dorsal habitus B Lateral habitus C Specimens labels, mouthparts, and male genitalia D Male genitalia, lateral view.

Figure 35. Homothermon serrano Ohaus paralectotype male from ZMHB. A Dorsal habitus B Lateral habitus C Specimens labels and male genitalia D Male parameres, caudal view.