Lionepha probata, (CASEY, 1918)

LIONEPHA PROBATA ( CASEY, 1918) View in CoL

( FIGS 1C, 15E, F, 11E, F, 14C, 9A, 21)

Bembidion probatum Casey, 1918: 22 View in CoL . Lectotype ♀, designated by Lindroth (1975), in USNM (type # 36817), examined. Type locality: Boulder County, Colorado.

Bembidion lubricum Casey, 1918: 21 View in CoL . Lectotype ♂, designated by Lindroth (1975), in USNM (type # 36820), examined (including genitalia). Type locality: Truckee, Nevada County, California. Synonymy established, under the name Bembidion erasum View in CoL , by Lindroth (1963).

Bembidion lascivum Casey, 1918: 21 View in CoL . Lectotype ♂, designated by Lindroth (1975), in USNM (type # 36821), examined (including genitalia). Type locality: Lake Tahoe, Placer Country, California. Synonymy established, under the name Bembidion erasum View in CoL , by Lindroth (1963).

Nomenclatural notes: This common and widespread species has long been known as Lionepha View in CoL (or Bembidion View in CoL ) erasa View in CoL (e.g. Lindroth, 1963; Erwin & Kavanaugh, 1981; Maddison, 2012). However, the lectotype of Bembidium erasum does not belong to this taxon (see nomenclatural notes under Lionepha erasa View in CoL ). We consider the three Casey names listed above to be synonyms. As first revisers of this group, we choose Lionepha probata View in CoL to be the name for this species. We have sequenced one of the paralectotypes of Bembidion probatum View in CoL (specimen USNMENT01114822) and have confirmed that it belongs to this species ( Figs 5–7; Supporting Information, Fig. S1).

Diagnosis: Specimens of this species are dark, with a broad prothorax with rounded sides ( Fig. 1C) and with relatively effaced, isodiametric microsculpture on the elytra ( Fig. 15E, F). As the elytral microsculpture can be nearly absent in many males, the shape of sculpticells can be difficult to observe. Ventral surface of the aedeagus curved, with apex slightly expanded ( Fig. 11E, F). Internal sac of aedeagus with large, distinct nub; sclerite CH 1 as in Figure 14C. The dorsal microtrichial patch of the female bursa is lobate or triangular, narrowing anteriorly, and is much larger than in L. erasa and L. australerasa ( Fig. 9A). The broad prothorax is indicated by PW/EL values, ranging from 0.463 to 0.498, with an average of 0.476 (N = 8).

From the similar L. erasa , distinguished by the darker colour, especially of the tibiae, and by the broader prothorax (in most specimens), as well as characteristics of the male genitalia ( Figs 11, 14) and bursal lobe of the female genitalia ( Fig. 9). For differences with the similarly dark L. australerasa , see the diagnosis under that species. Lionepha probata specimens might also be confused with those of the sympatric L. lindrothi , but the latter has clearly transverse microsculpture and, in general, narrower prothoraces.

Lionepha probata View in CoL is also similar in appearance to Bembidion commotum Casey, 1918 View in CoL , with which it is frequently microsympatric. In contrast to L. probata View in CoL , Bembidion commotum View in CoL has no elytral microsculpture on the disk, and nearly complete elytral striae. Bembidion commotum View in CoL also has a metasternal process bordered only laterally.

Additional characteristics: Body length 3.29–4.16 mm. Antenna piceous. Legs piceous, in a few specimens with slightly paler, rufopiceous tibiae. Hind wings full-sized. Chromosomes of male 24 + X ( Table 5).

Geographic variation: The 28S gene shows two forms that differ by two bases (positions 388 and 404 in the alignment deposited on Dryad). One form (having G at both sites) is eastern, from Colorado and Montana west to the White Mountains of California and the south-eastern corner of the Sierra Nevada, and in the north-west to the Warner, Steens, Wallowas and Blue Mountains. The other form occurs in the Cascades and much of the Sierra Nevada westward. The most distinctive populations are those in Utah, with the four Utah specimens having a one-base insertion in 28S; three of the specimens also differ at two sites from all other L. probata , with the fourth Utah specimen having double-peaks at both of those sites. The four Utah specimens form a distinct, well-supported clade in the COI tree ( Fig. 5), as well as the STACEY analysis ( Fig. 8).

Distribution: This widespread species is common from southern British Columbia south to the San Bernadino and San Jacinto Mountains near Los Angeles, east to Colorado ( Fig. 21). It is found in the broadest elevation range of any Lionepha species, from 65 to 3400 m. Specimens have been collected from April through November, with the majority being found in July and August.

Habitat: Found in many habitats close to some form of water. This species is common around the edges of melting snowfields in the Sierra Nevada and Cascades, as well as on the shores of creeks in forested areas (especially among mosses on sand or silt on the upper bank), but it can also occur in other habitats, such as in leaf litter around pools in an open forest floor.