The latest issue of The Coleopterists Bulletin arrived in my mailbox recently, and among the several papers of interest to me is a review of the North American species of the jewel beetle genus Chalcophora¹ (family Buprestidae). This genus contains some of the largest jewel beetles in North America and, due to their surface sculpturing and strict association with pine trees, are commonly referred to as “sculptured pine borers.” Four of the five species occur in the eastern U.S. and Canada, while only one, C. angulicollis, is found in the western states and provinces.
¹ I’d be interested to know how people pronounce this name. I’ve always pronounced it “kal-koh-FOR-uh”, but I’ve heard others use “kal-KAW-for-uh” or even “chal-KAW-for-uh.”
The review, authored by Crystal Maier and Mike Ivie at Montana State University, should put to rest a long-standing debate on the validity of the single western species. The four eastern species are distinct and easily distinguished from each other by virtue of color, presence/absence of ridges on the front legs, presence/absence of spines at the elytral apices, and, of course, male genitalia. Chalcophora angulicollis, on the other hand, has drifted in and out of synonymy under C. virginiensis, the most widespread of the four eastern species. The most recent changes in status were Bright (1987), who regarded C. angulicollis a synonym and treated all Canadian populations as C. virginiensis, followed by Nelson et al. (2008), who reinstated the former as a valid species. Neither of these actions were supported by any discussion of characters or detailed justification.
My impression has always been that the two species are distinct, and I have maintained specimens separately in my collection despite Bright’s synonymy. Chalcophora angulicollis always seemed to me a little more cupreous in coloration and a little more robust. I know that these are weak characters, and they can easily be a result of geographical variability within a species. However, considering the wide and nearly complete disjunction between the distributions of these two species across the nearly treeless Great Plains, it seemed to me prudent to consider them distinct until conclusively proven otherwise. I was therefore pleased to find out that my suspicions were correct when I visited Mike Ivie in Bozeman, Montana this past summer and learned of this manuscript in progress. Mike and his graduate student Crystal had found a morphological difference in the mouthparts that consistently distinguished the two species—C. angulicollis with the penultimate maxillary palpomere flattened and relatively shorter, while in C. virginiensis this structure is cylindrical and relatively longer. Correlated with these structural differences in the mouthparts are the relatively wider male genitalia of C. angulicollis (<3.3 times as long as wide, versus >3.9 times as long as wide for C. virginiensis) and its weakly serrate to crenulate posterolateral elytral margin (weakly to strongly serrate in C. virginiensis).
In addition to reevaluating the status of C. angulicollis and C. virginiensis, the paper provides high quality images of the dorsal habitus (see figure above), elytral apices, and male genitalia for all five North American species, a revised key to the species, and an updated distribution map showing locality/state records for the two aforementioned species in the context of forest cover in North America. Type material also was examined for all species, each of which is redescribed and annotated with abbreviated taxonomic synonymy (complete synonymies are available in other recent publications), notes on variation, comparisons with other species, and recorded hosts and distributions.
Bright, D. E. 1987. The Metallic Wood-Boring Beetles of Canada and Alaska. Coleóptera. Buprestidae. The Insects and Arachnids of Canada, Part 15. Agriculture Canada Publication 1810, NRC Research Press, Ottawa, 335 pp. [pdf].
Maier, C. A. & M. A. Ivie. 2013. Reevaluation of Chalcophora angulicollis (LeConte) and Chalcophora virginiensis (Drury) with a review and key to the North American species of Chalcophora Dejean (Coleoptera: Buprestidae). The Coleopterists Bulletin 67(4):457–469 [abstract].
Nelson, G. H., G. C. Walters, Jr., R. D. Haines, & C. L. Bellamy. 2008. A Catalogue and Bibliography of the Buprestoidea of American North of Mexico. Coleopterists Society Special Publication No. 4, The Coleopterists Society, North Potomac, Maryland, 274 pp. [description].
Copyright © Ted C. MacRae 2014