Cuyonysius Dellapé and Henry, 2020

Dellapé, Pablo M., Henry, Thomas J. & Pmd, 2020, A New Genus And Species Of Orsillinae (Heteroptera: Lygaeoidea: Lygaeidae) From Argentina, Proceedings of the Entomological Society of Washington 122 (1), pp. 55-62 : 56-57

Cuyonysius Dellapé and Henry ,

new genus

http://zoobank.org/5224a4e1-b6c6-

4188-9234-0d3e1f83d4b8

http://lsid.speciesfile.org/urn:lsid: Lygaeoidea.speciesfile.org: TaxonName:507252

Type species: Cuyonysius flavidus Dellapé and Henry , new species.

Description.—Elongate oval, somewhat depressed; body covered with appressed pubescence, and longer semierect setae dorsally. Head produced before eyes for distance slightly greater than length of eye; vertex low, not extending above eye more than one-quarter height of eye in lateral view, width slightly more than three times width of eye, carinae absent; antenniferous tubercle neither carinate nor produced beyond insertion of antenna; buccula coarsely punctate, high for entire length, ending broadly rounded at base of head; labium extending to mesocoxae; eye substylate; width including eyes less than width of posterior margin of pronotum. Pronotum trapeziform, not depressed or constricted. Scutellum with a Y-shaped tumid elevation; rounded apically. Hemelytron partially translucent, surpassing apex of abdomen; obscurely punctate along base of vein R+M and along claval suture; costal margin coincident with vein R+M to level of apical quarter of scutellum, then strongly expanded and gently arching to apex of corium; branch M of vein R+M intersecting apical margin of corium at a point closer to intersection of vein Cu than of branch R with apical margin of corium, these veins obscure; corium without a stridulitrum; membrane with two inner veins connected by a cross vein; edge of corium uniformly colored; acetabula impunctate. Fore femur unarmed. Pygophore projected posteriorly. Aedeagus without lateral conjunctival lobes. Distal conjunctival pigmented area with several membranous lobes.

Etymology.—The generic name is composed of the word “Cuyo [pronounced “coo-yo” in English],” the region in west central Argentina where this bug was collected, and the ending “nysius,” referring to the general resemblance of this large, complex and widely distributed genus of Orsillinae .

Discussion.—According to Ashlock (1967), a combination of characters is necessary to separate the Nysiini and Metrargini , with only the absence of a dorsal apical lobe on the conjunctiva of the aedeagus reliably distinguishing members of Metrargini from Nysiini . This leaves the Metrargini without a synapomorphy and highlights the need for a careful study of the generic characters in a phylogenetic framework to establish a robust tribal classification. Cuyonysius is placed in a new genus of the Metrargini based on the aedeagus having large, complex lobes on the vesica and a dorsal lobe on the conjunctiva absent; the corium with a row of punctures over the base of vein R+M and the claval suture; and the bucculae punctate.

Cuyonysius runs to couplet 10 and the genera Balionysius and Coleonysius in Ashlock’s (1967) key to genera of the Metrargini of the world, and to couplet 8 in the key to Neotropical genera ( Henry et al. 2015). These two genera are separated in the key by the rounded apex of the scutellum in Balionysius and an acute apex in Coleonysius , and by the macropterous or brachypterous condition of the hemelytra of each genus, respectively. All known specimens of Cuyonysius are macropterous and the apex of scutellum has an intermediate condition, which is rounded, but not broadly rounded as in Balionysius . Cuyonysius is distinguished from Balionysius by the shape of pronotum, the basally constricted hemelytra, the general color pattern, and the male genitalia. In Balionysius the pronotum is depressed at the callosities and the posterior margin is slightly wider than the width of the head across the eyes, the general coloration is mottled brown, the hemelytra are subparallel and opaque, and the posterior margin of the pygophore is rounded. In Cuyonysius the pronotum is trapeziform, not depressed or constricted, with the posterior margin clearly wider than the head width across eyes, the general coloration is yellowish brown, the hemelytra are constricted at the base and partially translucent, and the shape of the pygophore is projected posteriorly, which is unique in the tribe.