17MB PDF - Association for Mexican Cave Studies

184from Canada to Oaxaca, but only 3 species are known east of theGreat Plains. Species of Rhadine have a predilection for cool,dark habitats, and they are consequently found in mammal burrows,caves, cellars, and similar places. Some species (including R.euprepes from Mexico) live in forests, under rocks and logs. -Onlyone species group (the subterranea group) contains real troglobites,and these species are restricted to central Texas.Mexisphodrus, described as a new genus by Barr (Coleopt. Bull.,19:. 6s=72~ 1965), was first discovered in the s6tano del Profesor(Veracruz) by Terry Raines and Bill Bell. Additional species havebeen taken in a small cave at Jacala (Hidalgo) (Hendrichs andBOlivar~ 1966; Ciencia, 25: 7-10, pl. 1); the s6tano de Tlamaya(S.L.P.); and in the Sotano de la Joya de Salas and a small sinkholeat Rancho del Cielo (Tamps.) (Barr, 1966. ps~che, 73: 112-115).M. veraecrucis Barr and M. profundus Barr appear 0 be incipienttroglobites; they are wingless and depigmented and have very small,pale eyes. M. tlamaEfaensis Barr is a winged species with largeeyes, and ~.-gertsc Hendr. & Bol. is somewhat intermediate, stillretaining moderately well-developed eyes and a fairly dark pigmentation.Three undescribed species of the apparent troglobitevariety have been recently collected in Queretaro (s6tano de Camposantos,Cueva de las Tablas), San Luis Potosi (Valle de losFantasmos), and Oaxaca (S6tano de San Agustin).The special interest in Mexisphodrus derives from the factthat, until 1957, agonines belonging to the group of "true sphodrinesl1were known only from the Old World, ranging from theCanary Islands across the Mediterranean region into China. In1957 Straneo (Ciencia, 17: 81-84) describes the Mexican genusBo1ivaridius from surface material, suggesting that species ofthis genus belonged with the true sphodrines, despite lack of certaindiagnostic characters found in the European genera but not inthe Mexican one. Prosphodrus was described from New Zealand byBritton in 1959 (Proc. Entomo1. Soc. London (B), 28: 103-106)j P.wa1toni is a cave form (dark, with eyes) which, like Bolivaridius,appears to be a primitive sphodrine. The characters and generalbody form of Mexis1hodrus much more clearly suggest relationshipto the true sphodr nes than do those of Bo1ivaridius, but bothgenera are, in effect, ltmissing links" that make it difficult todraw arbitrary lines of classification and say what is a sphodrineand what is not. Other sphodrines inhabit Gruta del Pa1mito(N.L.), Cueva de 1a Boca (N.L.), and Texas caves of the Del Rioregion; these may constitute a third genus of North Americansphodrines, but their study has not yet been completed.The collection 1n November, 1966, of an eyeless, apparentlytroglobitic carabid of the tribe Scarit1ni, in the Sotano de laJoya de Salas, by Orion Knox and El Alexander, has added a remarkablenew element to the growing troglobitic fauna of Mexico.Scaritines, which include small to medium-sized, narrow-ltwaisted ltbeetles which burrow in gravel at the edge of streams, have only2 known trog1obit1c species--one in Yugoslavia and one in Italy-­both of which are apparently descended from hum1co1ous ancestorsand both of which, by evolutionary convergence, superficially resemblecave trechines. The Tamau1ipas cave scaritine, about 6.5 mmin length, 1s very different in appearance, although it, too, isrelatively slender and depigmented and without eyes. The bestguess that one can make at the present time is that this insect is