Trachusa ovata (Cameroni, 1902)

Kasparek, Max, 2019, A new species in the Trachusa ovata species group (Hymenoptera: Apoidea) from Peninsular Malaysia with an overview of the old-world species within the genus Trachusa, Journal of Natural History 53 (17), pp. 1079-1094 : 1081

The Trachusa ovata species group

The new species described here is closely related to Trachusa (Paraanthidium) ovata ( Cameron, 1902) , and it is herewith proposed to treat them as the ‘ ovata species group ’. Females of this group are characterised by a dark reddish brown to black ground colouration with a complete absence of light (yellow, ochreous) maculations. Legs are also dark with the exception of the tarsi which are somewhat brightened. Pubescence rufous and brown.

The female of the Palaearctic Trachusa byssina ( Panzer, 1804) is the only other entirely dark Trachusa species. It differs from the species of the ovata species group by a number of structural features (three versus four mandibular teeth, extended maxillary palpus, etc.) and is assigned to the subgenus Trachusa (Trachusa) s. str. With its rich pubescence and a different habitus (megachiliform body form in T. ovata species group; chalicodomiform body form with more slender, almost parallel-sided metasoma in T. byssina ) it is at first glance clearly distinct from the species of the ovata group (cf. Kasparek 2017).

In the female, the general appearance of the species of the ovata group is similar to the species of the Indomalayan longicornis group (see below for a list of species belonging to that group). However, the longicornis group members are characterised by dull yellow or ochreous markings particularly on apical terga, mostly in the form of somewhat irregular transversal stripes and maculations. As the males of the ovata group and also the males of some members of the longicornis species group are not known, the differences between them in the male gender still needs to be defined.

Within the subgenus Trachusa (Paraanthidium) , the members of the interrupta group with their typical yellow-black colour pattern are clearly distinct from the members of the ovata species group. The female of T. (Paraanthidium) xylocopiformis is still unknown. As the male is large, structurally different with relatively long, thin legs and relatively long wings, a distinctive colouration of hairs and other parts (e.g., reddish rather than black tegulae) it is evident that the material described here is not the still undescribed female of T. xylocopiformis . The remaining members of Trachusa (Paraanthidium) belong to the Subsaharan African realm and are clearly distinguished by structural and colouration features.