Rasopone

Longino, John T. & Branstetter, Michael G., 2020, Phylogenomic Species Delimitation, Taxonomy, and ‘ Bird Guide’ Identification for the Neotropical Ant Genus Rasopone (Hymenoptera: Formicidae), Insect Systematics and Diversity 4 (2), No. 1, pp. 1-33 : 9

Redefinition of Rasopone and Mayaponera

Schmidt and Shattuck (2014) provided the following diagnosis for Rasopone , based on workers: eyes present, mandibles relatively long, mandibular pit or groove absent, mesosomal profile nearly continuous, the metanotal groove shallow or absent, metapleural gland orifice without a posterior U-shaped cuticular lip, propodeal spiracle round or ovoid, mesotibiae dorsally without abundant stout traction setae, ventral apex of the metatibia with both a large pectinate spur and a smaller simple spur, fenestra absent from the petiolar process, prora present on anterior margin of first gastral sternite, and stridulatory organ absent from A4 pretergite. This should be emended to ‘prora absent’. There is no true prora in any caste of Rasopone or Mayaponera as defined here. In some cases there is a denticle on the sternite of the helcium that can be misinterpreted as a prora.

To Schmidt and Shattuck’s diagnosis we add the following characters: 1) petiolar sternite with deep transverse posterior groove such that posterior portion of sternite forms a shovel-like extension separate from tergite ( Fig. 1B ) (this character applies to all castes); 2) anterior margin of clypeus truncate to emarginate, never entirely convex ( Fig. 1E and F ); and 3) color light to dark red brown, never entirely black. These additional characters exclude the arhuaca complex. The arhuaca complex has a variously shaped anteroventral petiolar process, but the posterior portion of the sternite is closely appressed to the tergite. The anterior margin of the clypeus is convex, and the color is black.

Members of the arhuaca complex share many characters with Mayaponera constricta (currently the sole member of the genus), and the molecular data place them near each other (and distant from Rasopone ). The main morphological difference between Mayaponera constricta and the arhuaca complex is that the former has an impressed metanotal groove and the species of the arhuaca complex do not. Mayaponera constricta is a surface forager found in a wide variety of habitats, from mature forest to open or disturbed areas, and from wet to seasonally dry areas. It also has a very large geographic range, from Honduras to southern Brazil. In contrast, species of the arhuaca complex are found only in shaded rainforest habitats, and the species have smaller geographic ranges. In spite of these differences, we place the arhuaca complex in Mayaponera , and we consider the impressed metanotal groove of M. constricta to be a species-level trait and not a diagnostic feature of the genus. A full diagnosis of Mayaponera is not attempted here and should await a true revision of the genus.

Figures

Fig. 1. Characteristics of Rasopone species. (A) Habitus. (B) Scale-like petiole, showing definitions of petiole height (PTH) and petiole length (PTL), and the distinctive shape of the sternite. (C) Petiolar node intermediate between scale-like and cuboidal. (D) Cuboidal petiolar node. (E) Anterior clypeal margin truncate, with angulate lateral lobes. (F) Anterior clypeal margin sinuous, with rounded lateral lobes.