Lionepha osculans

L. osculans View in CoL group

L. osculans ( Casey, 1918) View in CoL

L. sequoiae ( Lindroth, 1963) View in CoL

L. pseudoerasa ( Lindroth, 1963) View in CoL

L. tuulukwa Maddison

IDENTIFICATION OF SPECIES

Most Lionepha specimens are difficult to identify to species using external morphological structures. Although the majority of specimens can be identified with good equipment and by the trained eye, many are only identifiable using male genitalia ( Figs 11–14), elytral microsculpture ( Figs 15–17), or DNA sequences. In most species, there are exceptional specimens that have prothoracic shape, elytral striae or other external characters that are outside the normal bounds of the species, and thus most species contain specimens that cannot be successfully identified using the external traits we have examined. In addition, the most important morphological characters, which are in male genitalia and elytral microsculpture, require special procedures or equipment to observe. The former requires clearing with KOH or enzymes and mounting in a medium with an appropriate refractive index (e.g. Euparal, clove oil or cedarwood oil). Within the L. osculans group, the male genitalia of each species are distinctive ( Fig. 13). Within the L. erasa group, genitalia are much more similar, and natural variation in the exact position of internal sac sclerites makes comparisons more difficult, but the shape of sclerite CH 1 ( Fig. 14) is often sufficient for identification. A clear view of microsculpture requires a high-quality, powerful microscope and appropriate lighting (either a ring light or diffuse light if a dissecting scope is used, or coaxial illumination if a compound scope is used).

The large number of tenerals of Lionepha that are captured, more so than is typical for bembidiines, complicates identification. The reason for the high frequency of tenerals is unclear. Perhaps they emerge after eclosion earlier than other bembidiines, and are thus more accessible to collectors, or perhaps they are soft and pale for a longer period. Whatever the cause, tenerals of otherwise dark species will look like paler species (e.g. the tibiae will be paler than a fully developed individual) and their genitalia (male or female) will be more difficult to study. The appendage colour described below pertains to fully developed individuals, not tenerals.

KEY TO SPECIES OF LIONEPHA

1. Specimens smaller, body length 3.29–4.42 mm (few specimens longer than 4.2 mm). Microsculpture on elytra absent or consisting of isodiametric or somewhat transverse meshes ( Figs 15, 16), but never transverse meshes or close-set transverse lines causing iridescence. Male genitalia with narrower apex, and with the characteristic pattern of internal sclerites shown in Figs 11, 12......................................... L. erasa group (2)

– Specimens larger, body length 4.26–5.90 mm (few specimens less than 4.4 mm). Microsculpture on elytra consisting of close-set transverse lines causing iridescence (e.g. Fig. 17A) or transverse meshes (e.g. Fig. 17C, D), or somewhat transverse ( Fig. 17G, H); never isodiametric or absent. Male genitalia with broader apex ( Fig. 13) ................................................................................................................................ L. osculans group (9)

2. Body relatively flat. Prothorax small relative to elytra ( Fig. 2D). Each elytron with at least five wellimpressed striae, and with outer striae nearly effaced, but evident. Microsculpture of elytra deeply engraved, even in males ( Fig. 16G), with slightly transverse or nearly isodiametric meshes....................... L. disjuncta

– Body relatively convex. Prothorax larger relative to elytra ( Figs 1, 2A–C). Striae less well-developed in general. Microsculpture less deeply engraved on elytral disc of males ( Figs 15A, C, E, 16A, C, E), isodiametric or transverse ........................................................................................................................................................3

3. Males shiny, with microsculpture on elytral disc weak or absent, isodiametric or slightly transverse (in L. australerasa , Fig. 15C; treated under both couplets). Microsculpture on elytra of females isodiametric, or only slightly transverse (at most as in Fig. 15B, D). Aedeagus with dark, distinct nub (arrows in Fig. 14). Female bursa with triangular or lobate dorsal microtrichial patch, much wider posteriorly than anteriorly ( Fig. 9A, B) ...........................................................................................................................................................4

– Microsculpture on elytral disc of males easily visible under high magnification with appropriate lighting, with clearly transverse sculpticells ( Fig. 16A, C, E, G); microsculpture of females slightly transverse ( Fig. 16B, D, F, H). Aedeagus without a nub. Female bursa with rectangular dorsal sclerotized region, not wider posteriorly than anteriorly ( Fig. 9C, D)...............................................................................................................6

4. Prothorax broader, with more rounded sides ( Fig. 1C). Legs dark, piceous, nearly as dark as body. Male genitalia with ventral surface more curved, near apex more abruptly curved downward (and thus the apex expands towards the tip; Fig. 11E, F). Internal sac of aedeagus with dark nub large ( Fig. 14C); sclerite CH 1 as in Fig. 14C. Females with large dorsal microtrichial patch on bursa ( Fig. 9A)........................... L. probata

– Prothorax narrower relative to elytra, with less rounded sides ( Fig. 1A, B). Legs lighter than body, or as dark. Male genitalia with ventral surface straighter, with apex not expanded toward tip ( Fig. 11A–D). Internal sac of aedeagus with smaller nub ( Fig. 14A, B); sclerite CH 1 as in Figures 14A and B. Females with smaller dorsal microtrichial patch on bursa ( Fig. 9B) .....................................................................................................5

5. Prothorax wider (PW/EL 0.467 –0.478,> 0.47 in most specimens), sides more rounded ( Fig. 1A); hind angles in most specimens, therefore, more obtuse. Tibiae distinctly paler than body. Microsculpture of elytral disk isodiametric, or nearly so (rarely slightly transverse; Fig. 15E, F). Sclerite CH 1 as in Figure 14A. From Oregon (Coast Range, central Cascades) north to Alaska .................................................................... L. erasa

– Prothorax small, narrow (PW/EL 0.438 –0.466, <0.46 in most specimens), more parallel-sided, sides straighter, especially posteriorly ( Fig. 1B); in most specimens hind angles thus less obtuse. Tibiae dark, same colour as body. Microsculpture slightly stronger, evident on elytral disk, although faint in males; always slightly transverse ( Fig. 15C, D). Sclerite CH 1 as in Figure 14B. Sierra Nevada of California north to Crater Lake , Oregon ............................................................................................................ L. australerasa

6. Legs paler, with tibiae clearly paler than body. Dorsal microtrichial patch of female bursa rectangular, not narrowing anteriorly, with multiple, deep, parallel, longitudinal folds ( Fig. 9C, E) ....................................7

– Legs darker, as dark as, or nearly as dark as, the body; males shinier, with less-impressed sculpticells. Dorsal microtrichial patch of female bursa rectangular and not narrowing anteriorly, without deep, parallel folds, or triangular and lobate, much wider posteriorly than anteriorly ( Fig. 9B, D, F) ................8

7. Fourth stria nearly effaced, much less impressed than the first. Sclerite CH 1 as in Figure 14D. Triangular scales on left-most membrane of internal sac ( Fig. 18). In the Cascades and westward, as well as the northern and coastal areas of California ............................................................................................ L. casta

– Fourth stria only slightly less impressed than the first. Sclerite CH 1 as in Figure 14E. Left-most membrane of internal sac without scales. In the Blue Mountains and Wallowas of Oregon and Washington east to Montana and Wyoming ............................................................................................................. L. kavanaughi

8. Microsculpture of the elytra more deeply engraved, complete sculpticells evident in the male, although slightly effaced; females duller. Sclerite CH 1 as in Figure 14F. Dorsal microtrichial patch of female bursa rectangular and not narrowing anteriorly ( Fig. 9D)..................................................................... L. lindrothi

– Microsculpture slightly weaker, often without complete sculpticells in males ( Fig. 15C, D). Sclerite CH 1 as in Figure 14B. Dorsal microtrichial patch of female bursa triangular and lobate, much wider posteriorly than anteriorly ( Fig. 9B) .......................................................................................................... L. australerasa

9. Elytral microsculpture consisting of less transversely stretched meshes, in males with most sculpticells being about three times as wide as tall ( Fig. 17G), in females brick-like and deeply engraved ( Fig. 17H); thus, the elytra in females are quite dull. Prothorax narrow, only slightly wider than head. Aedeagus with reduced internal sac sclerites ( Fig. 13G, H). Oregon Coast Range and Trinity Alps of California ........................................................................................................................................................ L. tuulukwa

– Elytral microsculpture more transverse, with less of a tendency to form distinct sculpticells ( Fig. 17A–F) .........................................................................................................................................................................10

10. Elytra not iridescent. Males with small basal protarsomeres, only slightly wider than second protarsomere ( Fig. 19B) ......................................................................................................................................... L. sequoiae

– Elytra slightly to notably iridescent because of transverse microsculpture. Males with large basal protarsomeres, much wider than second protarsomere ( Fig. 19A, C)..........................................................11

11. Elytra with reduced elytral striation, with third stria not visible beyond posterior dorsal puncture. Elytra only slightly iridescent. Prothoracic sides less rounded ( Fig. 3C), in most specimens with the posterior portion being almost parallel sided. Aedeagus with ventral surface gently curved ( Fig. 13E, F) .................................................................................................................................................... L. pseudoerasa

– Elytra with at least third stria visible beyond posterior dorsal puncture, and second stria almost reaching apex. Elytra distinctly iridescent. Prothoracic sides more rounded ( Fig. 3A). Aedeagus deep, with ventral surface sinuate ( Fig. 13A, B).......................................................................................................... L. osculans

SPECIES ACCOUNTS