Nyia, Márquez-Acero & Lambkin & Lamas, 2021

Márquez-Acero, Ángela Sabrina, Lambkin, Christine L. & Lamas, Carlos José Einicker, 2021, Cladistic analysis of Ligyra sensu lato (Diptera: Bombyliidae), with description of a new genus, Zoological Journal of the Linnean Society 191 : -

Nyia

The Nearctic and Neotropical species included in our analysis form a fully resolved monophyletic group in all MPTs distinct from Euligyra , Hyperalonia and Ligyra s.s., and are herein treated as a new genus of Exoprosopini ( Fig. 2). The characters that support the group are, among others: foretibia longer than 0.75 of foretarsus (49: 1), except in Ny. bizona (Walker) ; and subepandrial sclerites longer than the width of the gonocoxae (125: 3), except in Ny. harpyia (Wiedemann) .

In 1994, Yeates described the characteristics that distinguished the tribes Villini and Exoprosopini , in particular the form of the pulvilli. In our analyses we observed that for Villini , mid and hind pulvilli are round (57: 1, 64: 1), while in Exoprosopini they are chisel-conical in shape (57: 2, 64: 2). However, in Nyia and Hyperalonia , the pulvilli are round, as in Villini . Additionally, while in the Villini , and a large part of Exoprosopini , the hind pulvilli are more than half the length of the hind-tarsal claws (63: 2), in Hyperalonia and Nyia the pulvilli are less than one-quarter the length of both the mid- and hind-tarsal claws (56: 3, 63: 3).

Of particular interest are the characters ‘mid and hind pulvilli small rounded and setose’ ( Fig. 3C). These characters may be considered to have undergone reversal separately in Hyperalonia and Nyia . Although they are traditionally recognized for distinguishing the Villini ( Yeates, 1994) , they also appear in Hyperalonia and Nyia , the two genera with distributions in Nearctic and Neotropical regions, included in this study. Also, an important character is that the foretarsal microchaetae ends slightly bent in Villini (51: 2), bulbous (51: 1) in almost all Exoprosopini [a few with ends distinctly bent (51: 3)] and appear as a reversal to the slightly bent state (51: 2) for Hyperalonia , nine taxa of Nyia and four taxa of Euligyra .

Examination of character distribution showed that the female genitalia of Ligyra s.s. and Lig. sinuatifascia are more like Ny. cerberus, Ny. fenestralis (Wiedemann) , Ny. latreillii (Wiedemann) and Ny. pilatei . Meanwhile, Lig. satyrus , Euligyra and Hyperalonia are more like Ny. dido, Ny. evansi (Painter) , Ny. gazophylax (Loew) , Ny. hela (Erichson) , Ny. orcus (Walker) and Ny. stymphalis (Wiedemann) . Regarding the male genitalia, Nyia are similar to Ligyra s.s., Lig. satyrus and Euligyra , but different from Lig. sinuatifascia .

When the genitalia of Nyia and Hyperalonia are compared, several differences are observed. For example, in males, while all Nyia have an epandrium with a medial flange (118: 1 or 2), Hyperalonia has an apical flange (117: 1), the subepandrial sclerites are single in Hyperalonia (124: 4) but double and in different forms in Nyia (124: 1, 2 or 3), and the basiphallus is expanded in Nyia (161: 1 or 2) and not expanded in Hyperalonia (161: 0). In females, the T8 apodeme does not have internal structure in Hyperalonia (178: 0) but does in Nyia (178: 1), and the long, pump papillae are pigmented in Nyia (185: 2) and unpigmented in Hyperalonia (185: 1). With respect to similarities, it was observed that the spermathecal complex in female Hyperalonia is like that of Ny. hela, Ny. gazophylax, Ny. stymphalis and Ny. orcus .

While the matrix has been used here to examine support for the generic status of the specimens present in the new world, some characters support species groups in Nyia ; for example, the clade ( Ny. harpya + Ny. maracaensis ) is supported by the absence of scales on both face and frons (2, 3: 0), and triangular subepandrial sclerites (124: 2), where most species of Nyia have linear subepandrial sclerites.

(( Ny. fenestralis + Ny. latreillii ) + ( Ny. bizona + Ny. stymphalis )) is a clade supported by anal cell broad, rounded (97: 0), and gonocoxae with setae tuft (126: 2). Although we could not detect a link between the distribution of the species and their phylogenetic position, it is striking that of this complex of four species, three of them ( Ny. fenestralis, Ny. bizona and Ny. stymphalis ) are present in the Neotropics. Nyia latreillii is the only species of wide Neotropical distribution and also found in the Nearctic region.

The characters length of scape (26: 2) and length of basal stylomere (31: 4), both more than 3× length of the pedicel, separate the clade ( Ny. hela + Ny. orcus ) from the remaining Nyia . The clade ( Ny. alacer + Ny. evansi ) is supported by scales forming a carpet on face and frons (2, 3: 3), and epiphallus with apicodorsal plate (151: 2). Among all exoprosopinies, besides Ny. alacer and Ny. evansi , this last character is only present in Ligyra sinuatifascia .

In general, the characters associated with male genitalia, such as the subepandrial sclerite form (124) and setae on the epandrium (113–115), were informative and helped differentiate clades within Nyia . Also important in distinguishing species-groups of Nyia , were characters of the female genitalia, wings or legs; for example, sperm pump tube (193), membranous base of sperm pump (199), anal cell form (97) and foretarsal microchaetae ends (51).

Ligyra trifigurata was considered by Painter & Painter (1974) to be a subspecies of Lig. cerberus . Evenhuis & Greathead (1999) did not recognize subspecies and synonymized Anthrax trifigurata with Lig. cerberus . In our results, Lig. trifigurata is inferred to be a distinct and separate species from Ny. cerberus . Although we did not have access to the lectotype in BMNH examined by Evenhuis & Greathead (1999) (see Supporting Information, Appendix S1), the material that was examined by us is the same as that reviewed by Painter & Painter (1974), which we consider sufficient to propose the resurrection of Anthrax trifigurata from synonymy with Ligyra cerberus and its new combination with the new erected genus as Nyia trifigurata . According to Neal Evenhuis (pers. comm. May 2020), who examined the type material in BMNH, the specimens under that name belong to only one species, thus there is no reason to examine the lectotype to assure proper identification. Examination of the material examined by Painter & Painter in 1974 is sufficient for species identification.