The Aradidae of Chile (Hemiptera: Heteroptera) Author Heiss, Ernst text Linzer biologische Beiträge 2017 2017-07-28 49 1 147 158 journal article 10.5281/zenodo.5356557 0253-116X 5356557 Isodermus gayi ( SPINOLA , 1852) ( Figs 12-15 ) Anchomichon Gayi SPINOLA, 1852: 216 (original description) Achomichon Gayi : GAY 1854 : plate XI (= Hemipteros lámina 1, Fig. 14 ) (fig. F with broken hemelytra) Isodermus gayi : STÅL 1873: 147 (taxonomy) Isodermus gayi : WYGODZINSKY 1946: 266 (redescription, figures genitalia etc.) Isodermus gayi : KORMILEV & FROESCHNER 1987: 94 (catalog) Isodermus gayi : COSCARON & CONTRERAS 2012: 32 (catalog, bibliography) Isodermus gayi : CONTRERAS & COSCARON 2012: 11 (distribution, fig. habitus 3) SPINOLA gave in his description no locality information as well as several later literature citations, which mention only Chile (cf. COSCARON & CONTRERAS 2012 ). M a t e r i a l e x a m i n e d 13, 1♀ , 8L5 (in alcohol) with label: Chile : Cautin Pr. : P.N. Villarica , Volcán Villarica , road to ski center, 1390m , 39°23.27’S , 71°57.82W , 27.xii.1996 , stunted Nothofagus pumilio forest ; under bark Nothofagus pumilio logs, A. Newton & M. Thayer 981, Field Museum Nat. Hist. (macropterous specimens without broken hemelytra, FMNH ) ; 233, 1♀ with label: Chile : Malleco Pr. : P.N. Nahuelbuta , vic. Pehuenco ( Centro de Visitantes ), 1130m , 37°49.6’S , 73°00.47’W , 25.xii.2002 , Nothofagus sp. (decid.) w/shrubby understory, no bamboo: under bark, Solodovnikov 1056, Field Museum Nat. Hist. (macropterous specimens without broken hemelytra, FMNH ) ; 13, 1♀ 21 V 2001 / Las Trancas / Chili (region X) // S40.30391° / W 73.36397° / Alt. 320m GPS 58 // Bord de route, bois, / grumes, sous écorce / J-C Streito // (specimens with broken hemelytra, CEHI ) ; 1♀ Feuerland / Ushuaia , Nielsen / 30 I 1931 // (unbroken hemelytra, CEHI ) ; 3♀♀ // Chile : Magelhaes / I.Navarino / Pto. Williams / 6.8. III.1961 // Boris Malkin / Collector / Bishop Museum // (broken hemelytra, CEHI ) ; 633, 10♀ Chile / Chuquenco / XI 1977 / E.E. Peña // (broken & unbroken hemelytra, CEHI ) ; 433, 3♀♀ Chile W Reg. IX / Lastaria-Loncoche / 24 I 2005 Snižek lgt. // (broken & unbroken hemelytra, CEHI ) ; 433, 4♀♀ , 1L5 Chile VII r. 14-16.5 / 2005 Alto Vilches / 35°35’949 – 71°02’947 / 1400- 1800m , S. Bilý lgt. // (broken & unbroken hemelytra, CEHI ) . The genus Isodermus is regarded as a typical Gondwanian faunal element with circumantarctic distribution from Australia , New Zealand and Tasmania to southern South America. To date six species are described but Isodermus gayi is the only one occurring in South America. WYGODZISKY, 1946 published a scholarly detailed study of this species including genitalic structures and refers to the sexual dimorphism in the size of spines of the fore femora. Figs 12-15 : Isodermus gayi ( 12 ) male with complete membrane; ( 13 ) female with complete membrane; ( 14 ) male with membrane broken at level of scutellum; ( 15 ) female, ventral side. There is a tendency to break off the membrane of the hemelytra at a line of weakness at level of apex of scutellum. The reason is unknown and broken hemelytra can be observed in both sexes usually macropterous. D i s t r i b u t i o n: Chile (literature citations without localities), Los Muermos forest, Puntarenas; Argentina (several localities cf. COSCARON & CONTRERAS 2012 a).