Ctonoxylon Hagedorn, 1910

Jordal, Bjarte H., 2024, An integrated taxonomic revision of Ctonoxylon (Coleoptera, Curculionidae, Scolytinae) reveals new Malagasy species originating from multiple recent colonisations of the island, ZooKeys 1203, pp. 95-130 : 95-130

Genus Ctonoxylon Hagedorn, 1910

Type species.

Ctonoxylon auratum Hagedorn, 1910: 4 , subsequent designation by Hopkins (1914): 119.

Diagnosis.

Typical for subtribe Xyloctonina , with stout and rounded body shape, eyes divided, and protibia on its anterior face with a deep groove. Antennal funiculus 7 - segmented, club with oblique lateral septum, sutures faint or obscure, asymmetrical; pronotum with pair of teeth in females at the anterior margin, in males just behind anterior margin, teeth occasionally fused, or divided into four parts. Elytral declivity steep, abdominal ventrites flat or gently rising towards elytral apex.

Sexual dimorphism.

Dimorphism between males and females has not been clearly formulated in previous work. Nevertheless, the male pronotum has a pair of raised teeth located a little behind the front margin whereas the females have the pair of teeth at the margin and slightly closer to each other. Occasionally the male frons is also slightly modified in some species, either with the central area shinier, or with longer setae, or with patterns of transverse wrinkles. In at least one species ( C. montanum ) the degree of inflation of the elytral apex differs between the sexes ( Schedl 1972).

Comments.

Recent phylogenetic analyses ( Jordal 2023) supported a separate position of Ctonoxylon in Xyloctonina as the sister lineage to the three other genera Scolytomimus , Xyloctonus , and Cryphalomimus .