The rediscovery of Stenogeocoris horvathi Montandon (Heteroptera, Geocoridae) in Argentina

Stenogeocoris Montandon, 1913 was described to include S. horvathi based in one specimen from Córdoba Province, Argentina. The type specimen is lost and there are no records or additional material since the Montandon’s description; thus, the identity of this taxon has remained uncertain until now. In this contribution, we redescribe the genus Stenogeocoris and the species S. horvathi, based on male and female specimens, including characters from the male genitalia, and compare Stenogeocoris with the other Neotropical genera.

The species Stenogeocoris horvathi was described by Montandon (1913) based on one specimen from Córdoba Province, Argentina.The type specimen is lost and there are no records or references to additional specimens since Montandon's description, thus the identity of the taxon remained uncertain until now (Dellapé, 2014).
In this contribution, we redescribe S. horvathi and compare Stenogeocoris with the other Geocorinae Neotropical genera.Photographs of collecting areas, the adult male and female, and illustrations of the male genitalia are included.

MATERIALS AND METHODS
The specimens were sampled using pitfall traps consisted of open plastic containers, with a capacity of 1000 ml and 12 cm of diameter and filled with 300 ml of 30% ethylene glycol.Trap contents were collected after 15 days and fixed in 70% ethyl alcohol (Cheli & Corley, 2010).
Color images were captured using a digital camera (Micrometrics 391CU, 3.2 m) mounted on a Nikon SMZ1000 stereomicroscope.Multiple focal planes were merged using Micrometrics SE Premium 4 software.The genital structures were dissected under a stereomicroscope, cleared in a 10% KOH aqueous solution, washed in distilled water, and preserved in vials with glycerin.All measurements are in millimeters.
The following acronyms are used for specimen depositories cited in this paper: MLP (Museo de La Plata, Buenos Aires, Argentina) and CNP-CE (Entomological Collection, Instituto Patagónico Para el Estudio de los Ecosistemas Continentales, Puerto Madryn, Chubut, Argentina).
Discussion.Stenogeocoris seems to be related to Geocoris, a large and worldwide genus, with about 127 species (Baranowski & Slater, 2005), that appears to be a composite of several genera or subgenera (Readio & Sweet, 1982;Baranowski & Slater, 2005).
Stenogeocoris shares with Geocoris the presence of a complete median sulcus on clypeus; the rostral segment II shorter than III, the absence of claval commissure, the basal three abdominal sterna not fused, and with many of the species actually included in the genus the semistylate eyes, overlapping and in contact with the anterior angles of pronotum.The elongate body, about three times longer than wide, and the subquadrangular pronotum, wider at the level of and slightly constricted behind the calli allows separation of Stenogeocoris from Geocoris.
When establishing Stenogeocoris, Montandon (1913) compared the genus with Stenophthalmicus (Costa, 1875), an Old World genus of elongate, depressed species, having a less expanded scutellum, but pointed out that the shorter body and more cylindrical pronotum distinguished Stenogeocoris.
The strongly stylate eyes and a rostrum with segment II longer than III in Isthmocoris, and the clypeus with only a weak sulcus, the well-developed claval commissure, and the often fused basal three abdominal sterna in Ninyas, will distinguish these two genera from Stenogeocoris. Henry et al. (in press) presented a key to separate the four Neotropical genera of Geocorinae.
Coloration.General coloration black, except the areas as follows: apex of clypeus, juga and a small area before antenniferous tubercles pale brown (forming a fringe from eye to eye), buccula outline whitish.Antenna light brown, tinged with red, distiflagellomere lighter.Rostrum brown.Hemelytra fuscous, with raised calli on claval area and distal fringe whitish.Acetabular areas, auricle, and metaepisternum dorsally whitish.Prosterna light brown.Prosterna and propleura delimiting a lighter collar-like area.Legs: femora brown except apices paler, rest of legs light brown.
Female (Fig. 13): similar to male in all aspects.Abdomen wider.The female collected along Punta Ninfas Road has the whitish areas less evident and reddish tonalities on the antenna and legs.
Although there are several species with some degree of brachyptery in the Geocoridae, the modified staphylinoid forewings of S. horvathi are unusual within the family.Slater (1977) stated that this type of wing reduction is present in geophile or ground-inhabiting lygaeoids, a likely habitat for S. horvathi as suggested by our three specimens collected in pitfall traps.Presumably, it is a predator as are other members of the subfamily (Schuh & Slater, 1995).
Collecting sites.All specimens were collected in northeastern Chubut Province, Argentina (Figs 14,15).The annual mean temperature is 13.7 °C and the average annual precipitation is 188 mm, with a high mean interannual variation (Dellapé & Cheli, 2007).
Two specimens were collected in the Reserva de Vida Silvestre San Pablo de Valdés, located in southwestern Península Valdés.One female was collected in a shrub steppe (Fig. 16) dominated by Chuquiraga avellanedae Lorentz (Asteraceae), Lycium chilense Miers ex Bert.
An additional female was collected 15 km southeast of Puerto Madryn city (Punta Ninfas Road).The vegetation is a shrubland of Larrea spp.and Stipa spp.(Fig. 18), characteristic of the southern portion of the Monte Phytogeographic Province (León et al., 1998).