NEW RECORDS OF RHAMMATOCERUS VIATORIUS (ORTHOPTERA: ACRIDIDAE: GOMPHOCERINAE) FROM TEXAS, U.S.A

Abstract

The grasshopper Rhammatocerus viatorius (Saussure) occurs from South America northward to the southwestern United States (Otte 1981). In the United States, it occurs in south central Arizona, and there are two specimens collected in 1930 and 1931 from the Chinati Mountains in Presidio County (Figure 1) in Trans-Pecos Texas (Tinkham 1948). These are the only records of this species known from Texas. On 1 July 2005, the authors collected an adult male and an adult female Rhammatocerus viatorius on a rocky hillside with tall grass (60-80 cm in height) on route 118 northwest of the McDonald Observatory, north of Ft. Davis in the Davis Mountains, Jeff Davis County, Texas (Figure 1). The locality is approximately 2000 m (6500 ft) in elevation. Other grasshoppers observed at the locality with Rhammatocerus were Melanoplus lakinus, Melanoplus aridus, Opeia obscura, Dactylotum bicolor variegatum, Mermeria texana, and Eritettix tricarinatus. These are the first records of R. viatorius in over 70 years from Texas and are a northeastern range extension of that species’ occurrence in Texas by approximately 100 km (65 miles). The Chinati and Davis Mountains are not connected mountain ranges and have intervening desert. Thus, these individuals may be from an isolated population separate from those in the Chinati Mountains or they may be recent dispersers to Jeff Davis County. These new specimens will be placed in Texas A&M University Insect Collection (Department of Entomology, Texas A&M University). The occurrence of adults in the Davis Mountains in early July differs from reports of adults in the late spring in Arizona and the Chinati Mountains (Otte 1981). However, the morphology of the specimens is consistent with previously described specimens, having red hind tibiae, six to eight large black spots on the tegmen, and angular bands on the outer face of the hind femora. In addition, the sulci on the pronotum match those illustrated by Otte (1981), and the male specimen’s phallus and epiphallus do not differ from those illustrated for specimens from Mexico (de Assis-Pujol 1998). Additional collections are necessary to determine if these individuals are late survivors from the previous spring or if the Davis Mountains individuals occur at a different time of year. Volume 118, Number 3, May and June 2007 317