Trypoxylon

Amarante, Sérvio Túlio P., 2005, On The Systematics Of Trypoxylon scrobiferum Richards and T. anapaike Amarante With The Recognition Of A New Species Group In The Subgenus Trypoxylon (Hymenoptera: Crabronidae: Trypoxylini), Papéis Avulsos de Zoologia 45 (9), pp. 91-101 : 100

Subgenera in Trypoxylon

The placement of the scrobiferum group in the subgenus Trypoxylon narrows the concept of Trypargilum , and may even justify the synonymy of Trypargilum under Trypoxylon , with the species groups albitarse , superbum and nitidum as members of Trypoxylon . Alternatively, the ideas of Bohart & Menke (1976) could be adopted, who suggested that Trypargilum could be split into at least three subgenera – an opinion also shared by Coville (1982) – and some groups of Trypoxylon could be elevated to subgenera. The creation of the scrobiferum group adds offers support to these ideas, as I have shown here that some diagnostic characters of Trypargilum should be abandoned and others might be better regarded as the reunion of more than one character state into a single one. At the present, the autapomorphies of Trypargilum include the border of petiole socket uniformly concave or at most with an area slightly more depressed than its surrounding area and the male VIII sternum with long apical processes. However, if the shape of the petiole socket might be demonstrated to be a union of two or more distinct states, the male VIII sternum with long processes might be the only truly synapomorphic state supporting Trypargilum . Other conditions shared by the scrobiferum group and Trypargilum such as the frontal structure, presence of omaulus and subomaulus, gonostyli apically simple, might be regarded as symplesiomorphies retained within the subgenus.