Bembidion erosum (Motschulsky, 1850)

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 erosum (Motschulsky, 1850)

Peryphus erosus Motschulsky, 1850:10. Lectotype female, in ZMUM, examined, designated by Bousquet and Larochelle (1993), labeled “type” [handwritten], “California” [handwritten on red paper], " Peryphus erosus Mots California" [handwritten on green paper], [a rectangle of blank red paper], "LECTOTYPE Peryphus erosus Motschulsky Des. by Y. Bousquet ’91” [partly handwritten on red paper]. Type locality California.

Bembidion marinicum Casey, 1918:57. Holotype female in USNM (type number 36919), examined. Type locality Marin County, California.

Diagnosis and geographic distribution.

Most adults of this species are the darkest members of this group (Fig. 11B ), with the second and third antennomeres infuscated (Fig. 12B ), at least apically, and with dark femora, although the more northern populations (e.g., from mainland British Columbia) have paler legs and paler ground color of the body. Prothorax moderately cordate, with a smooth basal region with few punctures. Tip of aedeagus abruptly curved downward (Fig. 14C, D ); basal sclerotized lobe large (Fig. 15B ); apex of flagellar sheath with long, thin dark line (Fig. 16C, D ). This species is coastal, occurring from Haida Gwaii in British Columbia south along the coast to Big Sur and neighboring areas of California, with only one record from east of the Cascades (Fig. 20 ).

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 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 20. Geographic distribution of B. erosum.