Adetus scissicauda

Adetus scissicauda (Bates, 1874), reinstated (Fig. 6B) Tautoclines scissicauda Bates 1874: 225 Adetus scissicauda; Bates 1880: 107; Breuning 1960: 179 (catalogue, synonymy) Adetus alboapicalis Breuning 1943: 37; Monné 2023b: 428 (catalogue). New synonym Remarks. Bates (1874) described A. scissicauda based on a single specimen from Nicaragua. Breuning (1960) synonymised A. scissicauda with A. costicollis Bates, 1872. Breuning (1971) confirmed the synonymy but did not explain why he considered them as synonyms. However, the description of A. scissicauda does not suggest they are the same species. For example, Bates (1872) reported that the prothorax in A. costicollis is narrowed anteriorly [“ thorace antice angustato ”], whereas Bates (1874) indicated that the thorax is not narrowed anteriorly [“ capite thoraceque (antice haud attenuato) :::.” The general appearances of the holotype of A. scissicauda (Fig. 6B) and of the lectotype of A. costicollis (Fig. 6C) also do not allow considering them as belonging to the same species. Therefore, we believe that Breuning (1960, 1971) did not examine the type specimens when establishing the synonymy. Additionally, the elytral pubescence is different in these two species, especially that on the apical region, and A. costicollis has a distinct white pubescent spot just after middle of the elytra, which is absent in A. scissicauda. Furthermore, the elytral apex in A. scissicauda is obliquely truncate, and it is narrowly rounded in A. costicollis. Therefore, we are reinstating A. scissicauda. Breuning (1943) described A. alboapicalis based on a single specimen from Venezuela. Breuning (1971) separated A. alboapicalis (Fig. 6D) from A. costicollis as follows (translated): “Elytra notched apically,” leading to A. alboapicalis; and “Elytra rounded apically,” leading to A. costicollis. Breuning (1960, 1971) incorrectly interpreted the elytral apex in A. scissicauda based on a confused description by Bates (1874), who affirmed that it was obtusely rounded, and strongly emarginate near the suture [“ apice ipso obtuse rotundato, juxta suturam conjunctim fortiter emarginato ”]. In fact, the elytral apex in the holotype of A. scissicauda is identical to that in the holotype of A. alboapicalis. As the general appearance, including the pronotal and elytral pubescence, is similar in both holotypes, we consider A. alboapicalis to be a junior synonym of A. scissicauda. Adetus scissicauda is similar to A. griseicauda (Bates, 1872) (Fig. 6E) but differs in having sparser pronotal punctures (partially confluent in A. griseicauda), elytra with punctures not aligned (punctures aligned in A. griseicauda), and the elytral apex obliquely truncate (narrowly rounded in A. griseicauda). Adetus scissicauda is known from Mexico (Guerrero), Nicaragua, Panama, and Venezuela (Bezark 2023; Monné 2023b; Tavakilian and Chevillotte 2023).