Bembidion perspicuum (LeConte, 1848)

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 perspicuum (LeConte, 1848)

Ochthedromus perspicuus LeConte, 1848: 466. Holotype male, in MCZ (type number 5510), external structure and aedeagus examined. Type locality "Rocky Mountains".

Ochthedromus mannerheimii LeConte, 1852:190. Lectotype female, designated by Maddison and Swanson (2010), in MCZ (type number 35571). Type locality San Diego, California. Although a male in the same unit tray as the lectotype is, by genitalic characters, a member of Bembidion corgenoma , I am uncertain about the lectotype. The almost complete absence of the seventh stria and the pronotal shape suggests Bembidion perspicuum , but the base of the pronotum is not as punctured as typical for that species. I tentatively place it as a synonym of Bembidion perspicuum . However, as Bembidion mannerheimii LeConte, 1852, is a junior homonym of Bembidion mannerheimii Sahlberg, 1827, this name is unavailable in any event.

Bembidium haplogonum Chaudoir, 1868: 241. Neotype male, in MNHN, here designated, labeled "USA: California: Lake Co., North Branch Cache Creek at hwy 20, 305 m 38.9881°N, 122.54°W, 5.viii.2010. DRM 10.090. K.W. Will & D.R. Maddison", "David R. Maddison DNA5681 DNA Voucher" [pale green paper], "NEOTYPE Bembidium haplogonum Chaudoir designated D.R. Maddison" [partly handwritten, on white paper, bordered by red lines]. Genitalia mounted in Euparal in between coverslips pinned with specimen; extracted DNA stored separately. GenBank accession numbers for DNA sequences of the neotype are MW151478, MW151506, and MW151563. Details about the choice of neotype are provided below.

Bembidion acomanum Casey, 1918: 59. Lectotype female, designated by Lindroth (1975), in USNM (type number 36916), examined. Type locality Jemez Springs, New Mexico ( Lindroth 1975).

Bembidion excursum Casey, 1918: 59. Holotype female, in USNM (type number 36915), examined. Type locality Tucson, Arizona.

Bembidion tuolumne Casey, 1924:30. Lectotype male, designated by Lindroth (1975), in USNM (type number 36917), external structure and aedeagus examined. In Maddison and Swanson (2010), this was treated as tentatively a synonym of B. transversale . Further examination of the lectotype, including of its genitalia, reveal that this is a specimen of B. perspicuum . Type locality Tuolumne, California.

Designation of a neotype for Bembidium haplogonum Chaudoir.

Lindroth (1963: 341) could not find the original type series for Bembidium haplogonum Chaudoir in the MNHN. Thierry Deuve and David Kavanaugh have both searched for it, and could not find it in the Chaudoir collection, although other specimens were found that had been collected in California by Pierre Joseph Michel Lorquin. As the original type series is presumed lost, I here designate a neotype.

Chaudoir’s (1868) description of Bembidium haplogonum is detailed enough to make determination of the species he was describing clear. In his description, the large size (8 mm) and absence of a carina near the hind angle of the prothorax could only apply (within California, the type locality) to a member of the B. transversale group. The color pattern of the elytra (" sur les élytres, une petite tache au milieu du bord antérieur de chacune, et une bande transversale un peu arquée aux trois quarts, d’un jaune testacé pâle, peu distinctes, surtout la tache basale ", which translates to "on the elytra, a small spot on the front edge of each, and a slightly curved transverse band at three-quarters, of a pale testaceous yellow, indistinct, especially the basal spot") can only apply to some specimens of B. erosum , B. lugubre , or the northern, dark form of B. perspicuum (Fig. 11E ), as the other species in California have the entire basal third to half of the elytra pale. The description of the appendages as having the first 3.5 antennomeres, palps, and legs all pale yellow eliminates B. erosum , as the palps, femur, and antennomeres 2-11 are dark in California specimens of that species. I have seen no specimens of B. lugubre with an isolated small spot on the front edge of each elytron; the only specimens that have a pale area in the basal half of the elytra have the entire sides and basal regions of the elytra a pale rufous, with a darker disc; this paler form of B. lugubre occurs north of Los Angeles in California. The metallic coloration of the pronotum (" Le dessus d’un vert brillant un peu cuivreux ") is characteristic of B. perspicuum , but not B. lugubre ; the latter has no metallic sheen in any specimens I have seen from California, and in only very few individuals elsewhere. The flatter prothorax with less rounded sides and a wider lateral gutter is also distinctive of B. perspicuum relative to all three other species from California ( B. erosum , B. lugubre , and B. corgenoma ), as is the distinctly punctured pronotal base (" distinctement ponctué tout le long de la base "). The large size (8 mm) is more characteristic of B. perspicuum ; I have seen no specimens of B. corgenoma longer than 7.5 mm, but have seen specimens of B. perspicuum that are 7.9 mm in length, and specimens of B. perspicuum are, in general, larger than those of B. corgenoma . Finally, the virtual absence of the seventh elytral stria is characteristic of B. perspicuum relative to B. corgenoma . As Lorquin travelled extensively in areas where the dark form of B. perspicuum occurs ( Grinnell 1904), it is certainly reasonable that a specimen of that form could have been seen by Chaudoir.

My early interpretations of Chaudoir’s descriptions were in error, and led me to believe that Chaudoir’s specimen was a member of what I here call Bembidion corgenoma ; that mistake led me to call the species studied in Gustafson et al. (2019) Bembidion haplogonum . As a correct reading of the original description shows that Bembidium haplogonum refers to the dark form of B. perspicuum , I have designated a specimen from northern California with a color pattern matching Chaudoir’s description as the neotype (shown in Fig. 11E ).

Diagnosis and geographic distribution.

Adults of this species are large, and have a pronotum that is flatter than in other members of the group, with less rounded sides, and with the basal region more evidently punctate ( Maddison and Swanson 2010: fig. 4). At least antennomeres 4-11 infuscated. Specimens from most areas are relatively pale (Fig. 11D ), with the front half of the elytra pale, but specimens from northern California and Oregon are much darker (Fig. 11E ), with only elytral apices being pale. Aedeagal characterс are described in Maddison and Swanson (2010). This species is known from Texas, Kansas, Colorado, New Mexico, Arizona, Utah, Nevada, California, and Oregon.

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.