Eudesmus posticalis Guérin-Méneville, 1844

Heffern, Daniel, Nearns, Eugenio H. & Santos-Silva, Antonio, 2025, Description of two new species and new geographical records from the Neotropical region (Coleoptera, Cerambycidae), Zootaxa 5728 (1), pp. 173-186 : 182

Eudesmus posticalis Guérin-Méneville, 1844

( Fig. 17 )

Eudesmus posticalis Guérin-Méneville, 1844: 248 .

Remarks. Eudesmus is a very problematic genus and needs a full revision. We have often seen photographs of specimens with very questionable identifications. This seems to be much more common with the identifications of E. posticalis Guérin- Méneville, 1844 and E. grisescens Audinet-Serville, 1835 . Both were described from South America, respectively “ Brésil intérieur” [interior of Brazil], and French Guiana. Currently, Eudesmus grisescens is listed as having a large geographical distribution: “ Nicaragua, Costa Rica, Trinidad and Tobago, Panama, Ecuador, Peru, Bolivia, Venezuela, French Guiana, and Brazil (Amazonas) ( Monné 2024a; Tavakilian & Chevillotte 2025). On the other hand, E. posticalis is listed from Bolivia and Brazil (Amazonas) ( Monné 2024a; Tavakilian & Chevillotte 2025). Comparing photographs of the types of these two species, they appear to be quite similar. However, the syntypes of E. grisescens do not have a well-defined dark area on the apical half of the elytra, and the macula of whitish pubescence located anteriorly adjacent to this region does not have a curved posterior margin. Whether this difference is merely intraspecific variation remains uncertain for now. To make matters worse, there appears to be no reliable difference between E. caudalis Bates, 1865 and E. posticalis . Bates (1865) compared his species with E. rubefactus Bates, 1865 —a species that does indeed appear to be different—and not with E. posticalis . Interestingly, in the same work, Bates stated that he found E. posticalis at the same type locality as E. apicalis . Furthermore, Breuning (1958) described E. nicaraguensis from Nicaragua and reported: “Proche de grisescens Serv. , mais de stature plus large, les lobes inférieurs des yeux beacoup moins longs que les joues et la livrée légèrement différente [Close to grisescens Serv. , but broader, the lower eye lobes much shorter than the genae, and slightly different coloration.].” We have not seen a photograph of the holotype of this species, but we suspect it is identical to E. posticalis .

We believe that the specimen from Mexico, examined by us, corresponds to E. posticalis , which expands the geographical distribution of the species northward. We would not be surprised if the records of E. ferrugineus (Thomson, 1860) from Mexico actually correspond to E. posticalis .

Material examined. MEXICO ( new country record), Oaxaca: Sierra de Juárez , 850 m, 1 male, 20– 22.VIII.1991, G. Nogueira leg. ( DHCO) .

Figures

FIGURES 15–25. Dorsal habitus. 15) Hesychotypa albofasciata Pérez-Flores & Nearns, 2021, female. 16) Oncideres quercus Skinner, 1905, male. 17) Eudesmus posticalis Guérin-Méneville, male. 18) Physopleurus rugosus (Gahan, 1894), female. 19– 20) Tulcus picticornis (Bates, 1865): 19) Male from Honduras; 20) Holotype female. 21) Tulcus lycimnius (Dillon & Dillon, 1945), holotype male. 22) Tulcus lycimnius, figure 10 on plate IV, from Dillon & Dillon (1946). 23) Tulcus picticornis, figure 14 on plate IV, from Dillon & Dillon (1946). 24) Tulcus picticornis figure 7 on plate IX, from Bates (1880). 25) Tulcus picticornis figure 8 on plate IX, from Bates (1880).