Dendrobias Dupont, 1834

Vlasak, Josef & Santos-Silva, Antonio, 2018, New genus, species, redescription, and new rank in Cerambycinae (Coleoptera, Cerambycidae), Zootaxa 4446 (3), pp. 384-396 : 390

Dendrobias Dupont, 1834

Dendrobias Dupont, 1834: 41 ;

Trachyderes (Dendrobias) ; Monné, 2018: 961 (cat.).

Dupont (1836) provided the first key separating Dendrobias from Trachyderes (translated): “Mandibles of the males very projected, bifid and curved at their apices, mentum entirely sclerotized—leading to Dendrobias and Dicranoderes / Mandibles more or less similar in both sexes, mentum sclerotized at base, membranous toward ligula—leading to Trachyderes .” Dendrobias and Dicranoderes Dupont, 1836 were separated as follows (translated): “Sides of prothorax with a long spine… Dendrobias / Sides of prothorax with two large spines…. Dicranoderes .”

Laporte (1840) was the first who considered Dendrobias as a subgenus of Trachyderes . However, Laporte (1840) also considered Dicranoderes , Oxymerus Dupont, 1834 , Desmoderus Dupont, 1834 , Phaedinus Dupont, 1834 , and Xylocaris Dupont, 1834 , as subgenera of Trachyderes . Between Laporte (1840) and Hüdepohl (1985), all authors who wrote about Dendrobias considered it as a distinct genus.

Hüdepohl (1985) considered Dendrobias as a subgenus of Trachyderes (translated): “ Dendrobias Dupont is placed as a subgenus of Trachyderes Dalman ; it is not possible to separate the females of the two genera; males of Dendrobias are distinguished only by the enlarged mandibles and non-granulated scape (the remaining segments are granulated).” Hüdepohl (1985) separated Trachyderes (Trachyderes) from T. ( Dendrobias ) as follows: “Scape of males granulated; elytra black or chestnut-brown, usually with a common, transverse, premedian yellow band Subgen… Trachyderes s. str. / Scape of males not granulated; elytra yellow or yellow with brown to black design of stripes and bands… Subgen. Dendrobias Dupont. ” However, the difference in the sculpturing of scape is not true and, consequently, does not allow separating these subgenera. Actually, scape in males of some species of Trachyderes (Trachyderes) is distinctly not granulated. For example, scape in males of T. (T.) leptomerus boliviensis Aurivillius, 1908 , and T. (T.) hilaris Bates, 1880 , has no trace of asperities. Also, the color is not useful to separate the subgenera, since it is too variable in the species of both subgenera.

The argumentation by Hüdepohl (1985) to consider Dendrobias as a subgenus of Trachyderes seems to us to be poor. It is not rare that only one sex provides good features for separating genera in Cerambycidae . For example, males of Eburodacrystola Melzer, 1928 (Eburiini) have a conspicuous transverse sulcus at abdominal ventrites II– IV, with dense and long erect setae, while females lack the sulcus and cannot be separated from females of Eburodacrys White, 1853 . In this case, the difference in the mandibles of males (especially in large males) is so conspicuous that we believe that it makes no sense to consider Dendrobias as a subgenus of Trachyderes . Thus, we are replacing the former as a distinct genus. While most males of Dendrobias possess large conspicuous mandibles, some smaller specimens can have mandibles indistinguishable from those of females. This has been documented for Dendrobias mandibularis ( Goldsmith 1985) and it may probably also occur for D. steinhauseni and D. maxillosus . We believe that the male specimen ( Trachyderes (Dendrobias) sp.) depicted by Maes et al. (2010: 626—upper side of the page) represents a male of T. steinhauseni with very small mandibles.

Villiers (1980) provided a much better key separating Dendrobias from T. Trachyderes (translated): “Mandibles in males narrow, long and subhorizontal. Elytra yellow, concolorous… Dendrobias Serv. / Mandibles short and vertical in both sexes. Elytra reddish-brown with a transverse yellow band…. Trachyderes Dalm. ” Evidently, elytral color is not a good feature to separate these genera, but it is useful for species from French West Indies.