Bembidion transversale Dejean, 1831

Maddison, David R., 2020, Shards, sequences, and shorelines: two new species of Bembidion from North America (Coleoptera, Carabidae), ZooKeys 1007, pp. 85-128 : 85

Bembidion transversale Dejean, 1831

Bembidium transversale Dejean, 1831:110. Holotype female, in MNHN, examined by Kipling Will, who provided photographs that confirmed the identification. Type locality restricted to Nipigon, Ontario, by Lindroth (1963).

Diagnosis and geographic distribution.

Adults of this species (Fig. 11A ) are characterized by the reduced anterior lateral regions of the mentum (Fig. 13B-D ), and the antenna with at least the second and third antennomeres apically infuscated (Fig. 12A ). The prothorax is more cordate than in other species. The aedeagus has its ventral surface relatively straight, with the tip not abruptly curved downward (Fig. 14A, B ); the basal sclerotized lobe is large (Fig. 15A ), and the apex of the flagellar sheath has a long, thin dark line (Fig. 16A, B ). This is the easternmost species, found from Newfoundland and Nova Scotia west through Ontario to southeastern British Columbia, central Oregon, northeastern Nevada, northern Utah, and Colorado (western portion of distribution shown in Fig. 19 ).

Figures

Figure 11. Adult males of Bembidion transversale subgroup members A B. transversale (voucher V 101454, Canada: Alberta: Burbank, junction of Red Deer and Blindman Rivers, 52.3542 ° N, 113.7556 ° W) B B. erosum (voucher V 101453, USA: California: Del Norte Co., Wilson Creek, 3 m, 41.6051 ° N, 124.1005 ° W). C B. corgenoma (voucher V 101452, from type locality) D B. perspicuum, light form (voucher V 101461, USA: Arizona: Cochise Co., San Pedro R at Charleston, 31.6239 ° N, 110.1722 ° W) E B. perspicuum, dark form (neotype of Bembidium haplogonum Chaudoir, USA: California: Lake Co., North Branch Cache Creek at hwy 20, 305 m 38.9881 ° N, 122.5400 ° W) F B. sarpedon (voucher V 101459, USA: Colorado: Las Animas Co., Cokedale, Reilly Canyon, 37.1346 ° N, 104.6114 ° W). Scale bar 1.0 mm.

Figure 12. Antennae of B. transversale subgroup A B. transversale (voucher V 101457, Canada: Ontario: Thunder Bay Dist., Rossport) B B. erosum (voucher V 101456, USA: California: Del Norte Co., Wilson Creek, 3 m, 41.6051 ° N, 124.1005 ° W) C B. corgenoma (voucher V 101455, USA: Oregon: Coos Co., Crooked Creek S of Bandon, 43.0814 ° N, 124.4335 ° W). Scale bar 0.1 mm.

Figure 13. Mentum of B. corgenoma and B. transversale A Two specimens of B. corgenoma from Corvallis, Oregon B Two specimens of B. transversale from Hayden Lake, Idaho C Two specimens of B. transversale from Wallowa State Park, Oregon D Two specimens of B. transversale from Point aux Pins, Michigan.

Figure 14. Male genitalia of B. transversale subgroup A B. transversale (voucher DNA 4219, USA: Oregon: Harney County, Banks of Silver Creek, 1379 m, 43.7278 ° N, 119.6256 ° W) B B. transversale (voucher DNA 2161, Canada: Alberta: Lethbridge, Oldman River, 800 m, 49.7043 ° N, 112.866 ° W) C B. erosum (voucher DNA 4033, USA: Oregon: Curry Co., Floras Creek at route 124 SE Langlois, 21 m, 42.9132 ° N, 124.4251 ° W) D B. erosum (voucher DNA 3562, USA: California: Del Norte Co., Wilson Creek, 3 m, 41.6051 ° N, 124.1005 ° W) E B. corgenoma (voucher DNA 2180, USA: California: Sonoma Co., Russian River, 3 mi NE Healdsburg) F B. corgenoma (holotype, voucher DNA 5673, USA: Oregon: Benton Co., Corvallis, Willamette River, 60 m, 44.5491 ° N, 123.2449 ° W). Scale bar: 0.1 mm.

Figure 15. Basal sclerotized lobe of internal sac of male Bembidion transversale group members A B. transversale (voucher DNA 4219, USA: Oregon: Harney County, Banks of Silver Creek, 1379 m, 43.7278 ° N, 119.6256 ° W) B B. erosum (voucher DNA 4033, USA: Oregon: Curry Co., Floras Creek at route 124 SE Langlois, 21 m, 42.9132 ° N, 124.4251 ° W) C B. corgenoma (voucher DNA 2180, USA: California: Sonoma Co., Russian River, 3 mi NE Healdsburg). Scale bar: 0.1 mm.

Figure 16. Central sclerite complex of B. transversale subgroup A, B B. transversale (vouchers V 101437 and V 101436, USA: Michigan: Port aux Pins, Bois Blanc Isl.) C, D B. erosum (vouchers V 101440 and V 101439, USA: California: Del Norte Co., Wilson Creek, 3 m, 41.6051 ° N, 124.1005 ° W) E, F B. corgenoma (vouchers V 101428 and V 101430, USA: Oregon: Benton Co., Corvallis, Willamette River, 44.5475 ° N, 123.2428 ° W). Scale bar: 0.1 mm.

Figure 19. Geographic distribution of B. transversale and B. corgenoma (eastern portion of distribution of B. transversale not shown).