Isodermus gayi ( SPINOLA , 1852)

Heiss, Ernst, 2017, The Aradidae of Chile (Hemiptera: Heteroptera), Linzer biologische Beiträge 49 (1), pp. 147-158 : 152-154

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.

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).

Figures

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.