Comparative genitalic morphology in ten genera of thread-legged bugs of the tribe Metapterini, and its phylogenetic importance (Hemiptera: Heteroptera: Reduviidae)

Abstract

<jats:p>The assassin bug tribe Metapterini belongs to the subfamily Emesinae (Hemiptera: Heteroptera: Reduviidae). Morphologically, it is characterized by the conspicuous basal process of the posteroventral series in the foreleg and the presence of wing polymorphism, with a high proportion of the genera with micropterous or apterous species. Here, the male and female ectodermal genitalic structures are documented for ten genera and twenty-three species of Metapterini, including eight species of the speciose genus Ghilianella Spinola, 1850. Descriptions and digital macrophotographs are provided for abdominal segment 8, pygophore, parameres, and phallus of the male, and for tergite 8, tergite 9, gonocoxae, gonapophyses, gonoplac, and bursa copulatrix of the female. The asymmetric male genitalia within Emesinae are discussed. From this morphological documentation sixty six phylogenetic characters are coded, presented as a data matrix and analyzed cladistically, and their potential usefulness for resolving relationships among Metapterini is discussed.</jats:p>

A new species of Hornylia Wygodzinsky (Hemiptera, Heteroptera, Reduviidae, Emesinae) from Thailand

“…due to their similar appearance and several shared morphological characters: the anteocular part distinctly longer than postocular part; antennal insertion situated before the middle of the anteocular part but relatively far from apex of head; labial segment II at least twice as long as segment III; ventral spiny region of fore femur occupying at least half of the length of fore femur; fore tarsus with one segment, with decumbent, strongly sclerotized setae on ventral surface; mid and hind claws generally medially incised, without other projections; parameres without sensory spines (Wygodzinsky 1966;Rédei 2007Rédei , 2013Tatarnic and Cassis 2011). However, no comprehensive phylogenetic hypothesis is available for Emesinae, and only one species (Bargylia longinota Wygodzinsky, 1956) is included in recent morphology-based phylogenetic analyses of Metapterini (Castro-Huertas 2018. Therefore, a strict cladistic analysis is needed to clarify the generic relationships within this group.…”

“…Metapterini are characterized by the conspicuous basal process of posteroventral series of fore femur, and high proportion of genera with wing polymorphism (Wygodzinsky 1966;Castro-Huertas et al 2019). However, recent phylogenetic analyses based on morphology of genitalia (Castro-Huertas et al 2018) and fore leg (Castro-Huertas et al 2019) consistently indicate that Metapterini are paraphyletic with respect to Deliastini Villiers, 1949, show-ing that our knowledge on the evolution of Metapterini remains far from complete.…”

“…The type species, Hornylia nalanda Wygodzinsky, 1966, was described based on a single male specimen from Nalanda, Ceylon (now Sri Lanka) (Wygodzinsky 1966). No more information has been published since then except for being documented in the worldwide catalogue (Maldonado-Capriles 1990), and the female of Hornylia is still unknown (Castro-Huertas et al 2018), making this genus somewhat enigmatic.…”

Evolution of wing polymorphism and genital asymmetry in the thread‐legged bugs of the tribe Metapterini Stål (Hemiptera, Reduviidae, Emesinae) based on morphological characters

“…This occurs in two structures, at the dorsal phallothecal sclerite on its apex or in the lateral regions, and at the endosoma, in which the endosomal sclerites are arranged in an asymmetrical pattern. Species of Ghinallelia present both structures as conspicuously asymmetric, whereas species of Emesaya only have the endosomal sclerites with an asymmetrical pattern (Wygodzinsky, 1966; Castro‐Huertas et al ., 2018).…”

“…However, this hypothesis has never been tested with a phylogenetic approach. Recent studies with a limited taxon sampling analysing characters of male and female genitalia and prolegs (Castro‐Huertas et al ., 2018, 2019) have suggested that Metapterini might be paraphyletic with respect to Deliastini, although in those analyses, the taxon sampling was restricted to a few genera of Metapterini and thus did not capture the whole range of potential morphological variability.…”