Drasterius grandicollis Horn, 1829

Johnson, Paul J. & Lin, Xinjie, 2001, A Generic Change and New Distribution Record forAeolus grandicollis (Horn) (Coleoptera: Elateridae), The Coleopterists Bulletin 55 (1), pp. 10-10 : 10

Drasterius grandicollis Horn

(1871, Transactions of the American Entomological Society, 3: 299–324)

was described from a single specimen collected in ‘‘ California.’’ No collector or precise locality is attributed to this specimen. Through the 1880s and 1890s, Horn continued to receive material from ‘‘Lower California,’’ now Baja California, and worked on the fauna of that region (Horn 1894–1896, Proceedings of the California Academy of Sciences , 4: 302–449, 5: 225–259, 6: 367–381). Yet, he never listed this species from the peninsula or nearby regions. Yet, apparently no additional specimens of this species were obtained or are available in surviving collections.

Taxonomic treatment of the species of Drasterius by LeConte (1884, Transactions of the American Entomological Society, 12: 1–32.) and catalogers through Schenkling (1925, Elateridae I. Coleopterorum Catalogus , 88: 1–264. Berlin) retained grandicollis in this genus. However, this and other species were transferred to Aeolus Eschscholtz when Becker (1961, Canadian Entomologist, 93: 161–181) stated that those species listed under Drasterius in Leng’s catalog (1920, Catalogue of the Coleoptera of America, north of Mexico. John D. Sherman, Mt. Vernon , New York) should be so treated. Our examination of the type of D. grandicollis revealed that Horn’s assignment of this species to Drasterius does not fit the contemporary taxonomic concept of that genus. The holotype of D. grandicollis was found to lack the salient characteristics to retain its assignment in either Drasterius or Aeolus . Rather, the specimen possesses the traits to support a reassignment to Conoderus Eschscholtz as C. grandicollis (Horn) (new combination) and an association with C. sordidus (LeConte) and C. robustus (Horn).

Although Conoderus is a large and morphologically diverse genus requiring review, grandicollis fits the generic description of the genus given by Johnson (1995, Coleopterists Bulletin, 49: 59–71). Along with C. sordidus and C. robustus, this small group of species shares the following combination of traits within the genus: pronotum densely and doubly punctured with a field of fine punctures and intermixed coarser punctures approximately 2× larger in diameter than the fine punctures; lateral margin strongly sinuate before pronotal hind angles; pronotal hind angles bicarinate, with mesal carina very short, occasionally obsolescent; femur of front leg smoothly rounded on anteroventral angles; tarsomere 4 bearing a large fleshy ventral lobe; elytral apices conjointly rounded. Within the genus, C. grandicollis is readily recognized by its smaller size (6– 7 mm), coarsely punctured pronotum and elytral striae, ovate elytra lacking humeri, apterous metanotum, and pallid coloration. The style of pronotal sculpture is indicative of Heteroderes which Van Dyke (1932, Proceedings of the California Academy of Sciences, 10: 291–465) treated as a subgenus of Conoderus .

Three specimens, one from each of three localities were submitted for determination by W.H. Clark, Albertson’s College of Idaho, Caldwell (ACIC). These specimens represent a new country record and bear the following labeling: MEXICO: Baja California Norte , 1 km SE [of] San Telmo mine, Lt 29°35' Lng 114°46', 300 mEl, ethylene glycol pitfall trap, 5.vii.91 ­ 24.v.92, W.H. Clark, E.M. Clark, P.E. Blom collectors (1, ACIC); 6 km NE [of] La Bocana, Lat. 29°42'N, Long 114°50'W, Elevation 400 m, pitfall trap ethylene glycol 19.iii.91 ­ 5.vii.91, W.H., M.H., C.J., & K.D. Clark, & J.E. Luther collectors (1, ACIC); 9 km NW [of] Rancho Santa Ines , Lat 29°46'N, Long 114° 46'W, El. 550 m, pitfall trap #13 ethylene glycol 22.iii.91 – 17.vii.91, W.H., M.H., C.J., & K.D. Clark, & J.E. Luther collectors (1, PJJC) .

This note is publication # 3203 of the South Dakota Agricultural Experiment Station .