Olethrius macrothorax (Montrouzier, 1861)

(Figs. 13, 14)

Mallodon macrothorax Montrouzier, 1861: 285 .

Stenodontes (Nothopleurus) macrothorax; Lameere, 1913: 13 (cat.); 1919: 33.

Stenodontes (Opheltes) macrothorax; Lameere, 1903a: 129, 130, 139.

Olethrius macrothorax; Lacordaire, 1869: 117; Lameere, 1920: 137.

Opheltes auriculatus Thomson, 1861: 306; Lacordaire, 1869: 128; Thomson, 1878: 5 (types); Lameere, 1903a: 129 (syn.).

Opheltes macrothorax; Fauvel, 1906: 42.

Nothopleurus macrothorax; Hayashi, 1961: 12; Fragoso & Monné, 1995: 219; Komiya & Lorenc, 2006: 4 (checklist).

We believe that the inclusion of O. macrothorax (Montrouzier, 1861) in Nothopleurus by Fragoso & Monné (1995) was incorrect, and did not take into account the transfer made by Lameere (1920) from Stenodontes (Nothopleurus) to Olethrius . In fact, the transfer by Lameere (op. cit.) remained unknown to all the authors consulted by us (pers. comm.). Komiya & Lorenc (2006) for example, mention this species in Nothopleurus .

Thomson (1861) noted on Olethrius: “ Antennae ante oculos insertae, apud 3 quartam partem posteriorem, et apud Ƥ dimidium, attingentes, 11-articulate, art. 1º longissimo, caeteris singulis longiore, 2º– 3º conjunctim 1º aequale, apud 3 robustioribus; art. 4º precedente multum breviore, 4–11 subaequalibus, gradatim attenuatis. Mandibulae subverticales, apud 3 magis elongatae et magis robuste, intus excavate, et valde pluridentatae”. This generic description does not permit the inclusion of Mallodon macrothorax in this genus. In males of this species the scape is distinctly short (not surpassing the posterior edge of eyes), antennomeres III–IV together are much longer than the scape, and antennomere III is subequal to IV. Lacordaire (1869), in the redescription of Olethrius wrote that the scape is longer than antennomere III and that this is one-third longer than IV. The inclusion of Mallodon macrothorax in Olethrius, appears to be based on the incorrect identification of this species, as these characters do not apply to Montrouzier’s species. Although the type specimens of M. macrothorax are unavailable for study, we believe that the specimens we examined are of this species based on the type locality, and their close match to the original description and redescription of Lameere (1903a). There is another indication that this species does not possess the characters of Olethrius: Montrouzier (1861) while describing Mallodon edwardsii, immediately before M. macrothorax, wrote in a footnote that this species belongs to Olethrius, whereas in the previous species he did not record such a note.

Olethrius macrothorax (Figs. 13, 14), therefore, does not belong to the genus Nothopleurus; the former having the labrum sub-horizontal, distinctly visible in dorsal view, not depressed at the medial region in both sexes (in Nothopleurus it is vertical, not visible or nearly so in dorsal view, and distinctly depressed at the medial region); mandibles of males wider and with dorsal carina low (narrower and with dorsal carina elevated in Nothopleurus); elytral punctation distinct in both sexes (almost smooth in Nothopleurus or, at most, fine and sparse); lateral margins of pronotum crenulated (spined in Nothopleurus); anterior legs proportionally longer, primarily in males (proportionally shorter in Nothopleurus); tibiae without brush of hairs on ventral face in both sexes (with brush in Nothopleurus).

Olethrius macrothorax can be included in Hovorodon gen. nov. by similar diagnoses between Nothopleurus, except by the lateral margins of pronotum which are crenulate in both genera, and by the short galea, reaching the apex of the first maxillary palpomere (long in Hovorodon gen. nov. reaching or almost reaching apex of the second maxillary palpomere).

In Tavakilian & Chevillotte (1999), this species is recorded as Opheltes macrothorax . If in fact this species is assignable to Olethrius, it will have to be transferred to another genus and, necessarily that genus will have to be Opheltes, if the synonymy established by Lameere between Mallodon macrothorax and Opheltes auriculatus is correct. However, Opheltes will then require a new name, as it will become a junior homonym. We have opted not to take this action without examining the types of M. macrothorax and Opheltes auriculatus . Thus, we provisionally maintain this species in the genus assigned by Lameere (1920), out of which it was never formally transferred.

Since M. macrothorax remains incorrectly assigned to Nothopleurus in many works (e.g. Hayashi 1961; Fragoso & Monné 1995), Opheltes should appear as a synonym of this species, however, this is not the case (e.g. Monné 2006). Linsley (1962) was one of the few authors that included Opheltes as synonym of Nothopleurus (mentioned as Stenodontes ( Mallodon)). However, due to transfer of M. macrothorax to Olethrius, Opheltes is now a synonym of that genus.

Material examined. NEW CALEDONIA, Lifou: 2 males, 1 female [without date and name of collector] (IRSN).