(Fig. 35–38)
Type species. Rileyellus panamensis Wappes and Santos-Silva, here designated.
Etymology. Named to recognize Edward G. Riley (TAMU), entomology researcher and author, who has been the collector of several new cerambycid species from Panama, including this one. Latin “-ellus”, used to form a diminutive of a noun. Masculine gender.
Description. Head not retractile, not prolonged behind eyes; frons transverse; antennal tubercles slightly elevated, distant from each other. Eyes not divided, coarsely faceted; distance between upper eye lobes larger than twice length of one lobe; lower eye lobes longer than gena. Antennae 11-segmented, distinctly longer than body; scape somewhat sinuous, gradually widened from base to about posterior quarter, then narrowed, lacking apical cicatrix, reaching about middle of prothoracic length; antennomeres filiform; antennomere III sinuous. Prothorax transverse; sides with large, conical tubercle. Pronotum with transverse crest about center. Procoxal cavities open laterally and posteriorly. Mesoventral process lacking tubercle. Mesocoxal cavities open laterally. Elytra with tuberculate centrobasal crest, lacking longitudinal carina, and with oblique/arched crests; outer apical angle rounded; with long, erect setae. Femora slightly pedunculate-clavate. Ventral surface of protibiae excavated on base of posterior third. Metatarsomere I slightly shorter than II–III together.
Remarks. Rileyellus new genus is similar to Monnetyra Galileo and Martins, 2006, in the presence of a crest on the pronotum and elytra. However, it cannot be included in this genus because the prothorax has large lateral tubercles, which are absent in Monnetyra, and the mesotrochanters are not projected as a spine at apex (projected in Monnetyra). The general appearance is also similar to that of Blabia Thomson, 1864, but differs by the presence of a distinct transverse crest on pronotum (absent in Blabia) and by the outer apical angle of the elytra being rounded (often spinose in Blabia, but never rounded). Additionally, the scape in Blabia is typically not somewhat sinuous (except in B. banga Galileo and Martins, 1998, which is likely generically misplaced).