Pterostichus (Pseudoferonina) lolo Bergdahl

Bergdahl, James C. & Kavanaugh, David H., 2011, Two new species of Pterostichus Bonelli subgenus Pseudoferonina Ball (Coleoptera, Carabidae, Pterostichini) from the mountains of central Idaho, U. S. A., ZooKeys 104, pp. 77-96 : 83-85

Pterostichus (Pseudoferonina) lolo Bergdahl sp. n. Figs 23B4B, 4D57

Type locality.

U.S.A, Idaho, Clearwater County, Cottonwood Creek near the confluence of Orogrande Creek and the North Fork of the Clearwater River, ca. 870 m (2860 ft) elevation, 46.5528°; -115.5522°.

Type material.

Holotype, a male, deposited in CAS, labeled: "USA: IDAHO, Clearwater Co.; Cottonwood Creek @ USFS Rd 250; Orogrande Ck. Rd.; NF Clearwater R. watershed; elev. ~870 m (2860 ft); 12.5 MI. ESE Headquarters, 3.5 MI. SW of Bungalow; 46°33'10"N, 115°33'08"W; T38N, R7E, S34; 17 July 2009; #73-2009; J. C. Bergdahl, coll."/ "HOLOTYPE Pterostichus lolo Bergdahl designated 2011" [red label]. Paratypes: A total of 22 paratypes from same locale as the holotype (7 males and 5 females from 17 July 2010; 2 males and 9 females from 03 July 2010) deposited in CAS, CMNH, CNC, JCB, OSU, UICM and WSU.

Etymology.

The specific epithet, lolo, is a noun in apposition, and refers to the Lolo Trail, an ancient hunting and trade route developed by the Nez Perce tribe to cross the Bitterroot Mountains from their homelands on the Clearwater River near Kamiah, Idaho, to the buffalo herds of Montana. The beginning of this trail in its western foothills starts in the upper Lolo River watershed, near the type locality of Pterostichus lolo . The Lolo Trail is also the route the Lewis and Clark Expedition took over the Bitterroot Mountains heading west in September 1805 and east in June 1806.

Diagnosis.

A Pterostichus with the characteristics of members of subgenus Pseudoferonina (see Ball 1965; and Bousquet 1999); males easily distinguished from those of all other species of Pseudoferonina by the shape of the median lobe of the aedeagus, especially the form of the mid-shaft sinuation and associated convexity (Figs 4B and 4D), which is markedly and abruptly convex, nearly tuberculate (in lateral view), and the shape of the apical lamella (apex), which is broader in ventral view than in Pterostichus shulli males (see Bousquet 1992, Fig. 16) and narrower in lateral view than in Pterostichus spathifer males (see Bousquet 1992, Fig. 15).

Description.

Size medium-large for subgenus, ABL males = 9.5-10.5 mm, females = 9.0-10.3 mm. Body form average for subgenus (Fig. 2).

Color. Dorsal surface black and shiny, pronotal lateral beads piceous, antennae and palpi rufous or rufopiceus, femora piceous except distally rufopiceous, tibiae and tarsi rufopiceus or rufous.

Microsculpture. Head with faintly impressed isodiametric meshes on frons; pronotum with moderately impressed transverse meshes on most of disc, meshes more isodiametric posteriorly; elytra with moderately impressed transverse meshes and very slight iridescence. Pronotum.Fig. 3B. Almost as long as wide, widest point approximately at anterior one-third, lateral margins slightly sinuate in posterior half, almost parallel before hind angles, hind angles slightly obtuse to subrectangular, lateral margins (in lateral view) bent ventrally near hind angles, basal one-quarter of pronotum finely but distinctly punctate. Anterior and posterior transverse impressions faintly or not at all impressed, median longitudinal impression distinctly impressed, nearly extended to anterior and posterior margins in most specimens examined. Lateral margins finely beaded, posterior margin without margination, anterior margin minutely beaded in lateral thirds, without margination in medial one-third. Basolateral fovea deep and broadly linear, slightly convergent toward midline anteriorly, finely but distinctly punctate, areas between basal fovea and lateral margins convex, subcarinate.

Elytra. Intervals nearly flat, striae entire, moderately impressed, not or only very faintly punctulate. Legs. Male mesotibiae slightly curved apically. Abdomen. Last visible sternite of male with broad, shallow medial indentation, anterior margin of depression slightly carinate, sternite without protuberances; last visible sternite of males with single pair of anal setae, female with two pairs.

Male genitalia. Median lobe of aedeagus as in Figs 4B and 4D. Apical one-third of median lobe (in ventral view) with lightly sclerotized oblique band extended longitudinally next to slight ridge (Fig. 4Da); shaft of median lobe (in ventral view) markedly swollen submedially on left, with shaft abruptly tapered from swelling to the apical lamella, ventral margin distinctly sinuate subapically (in lateral view) with markedly abrupt, subtuberculate convexity basad of sinuation (Fig. 4Db); apical lamella average in length for Pseudoferonina species in Idaho, apex evenly rounded, very slightly swollen in ventral view (Fig. 4Da), narrow and very slightly reflexed ventrally at tip in lateral view (Fig. 4Db). Right paramere as illustrated by Bousquet (1992, Figs 15b and 16b) for Pterostichus spathifer and Bembidion shulli .

Geographic distribution.

Currently, Pterostichus lolo is known only from the type locality on Cottonwood Creek (at 870 m), which is a small, low-order tributary of Orogrande Creek, which is itself a tributary of the North Fork of the Clearwater River. In turn, the Clearwater is a tributary of the Snake River, which is a major tributary of the Columbia River. To what extent the range of this species is narrowly restricted to this area is not known. Despite sampling many other creeks in this area over the past decade, JCB has been unable to document any other Pterostichus lolo populations.

Habitat.

The type locality is in the Clearwater Mountains and Breaks section of the Northern Rockies eco-region ( Nesser et al. 1997). This area has mountains of moderate relief with rounded landform, and steep breaklands. Elevations range between ca. 610 and 2070 m (2000 and 6800 ft.). The climate is generally cool, with a significant maritime influence. Summers are warm and dry, winters cool and moist. The soils are mantled by a thick layer of Quaternary volcanic ash and colluvium, underlain by Tertiary granitic rocks of the Idaho Batholith and Precambrian gneiss and schists ( McGrath et al. 2002). Annual precipitation is ca. 889- 2032 mm, with 40-50% falling as snow. Snow packs at higher elevations can become very deep and linger late into spring. Rain-on-snow events are common below 1370 m (4500 ft.); January min/max temperatures: -8.3/0.6°C; July min/max temperatures are 7.2/27.2°C.

These mountains have been largely unglaciated and support a highly dissected stream network of ancient narrow valleys and canyons. Drainage density (length of stream/area) is high. The natural vegetation is primarily a very species-rich mosaic of mesic conifer forest, including exceptional conifer species diversity (grand fir, Douglas fir, western red cedar, western hemlock, mountain hemlock, ponderosa pine, lodgepole pine, white pine, western larch, subalpine fir, Englemann spruce and yew). Ponderosa pine/Douglas fir and cedar/hemlock/pine forests occur at lower elevations, and spruce/fir or mountain hemlock forests at higher elevations. Some of the forest types in this area are the best examples of inland temperate rainforest in the Rocky Mountain region ( Bergdahl 2008), including western red cedar trees estimated to be more than 3000 years old ( Smith and Fischer 1997). The flora of this region has many unique coastal disjunct species and the area is often referred to as the Clearwater Refugium (Brunsfeld et al. 2001, Carstens et al. 2005, Brunsfeld and Sullivan 2006).

Like all other species of Pseudoferonina , Pterostichus lolo appears to be a habitat specialist, primarily on the wet margins of small, low (0-2) order forest streams descending hillsides in mountainous country. These habitats are often isolated in headwater basins, or on breaks and canyon walls at lower elevations. These beetles are not aquatic, but they are strict hygrophiles. Surface-active adults are usually found within two meters of wet stream channels, primarily within one meter of the strandline and especially right at the water’s edge. When disturbed during warm weather, they will often run into the water and crawl down into the gravel or float away.

Other carabid species collected by JCB at or in the vicinity of the Cottonwood Creek locality include: Scaphinotus (Pseudonomaretus) regularis (LeConte), Scaphinotus (Pseudonomaretus) relictus (Horn), Scaphinotus (Pseudonomaretus) merkelli (Horn), Zacotus matthewsii LeConte, Trechus coloradense Schaeffer, Bembidion kuprianovi , Bembidion iridescens , Bembidion breve (Motschulsky), Pterostichus (Hypherpes) ecarinatus Hatch, Pterostichus (Leptoferonia) idahoae Csiki, Pterostichus (Leptoferonia) beyeri Van Dyke, Pterostichus (Pseudoferonina) shulli (Hatch) and Pterostichus (Pseudoferonina) vexatus Bousquet.

Phenology and larval ecology.

Adults of Pterostichus lolo are probably active from the first warm days of spring after snowmelt to the first days of hard frosts in October. A single pair of adults was observed in copulo, on 17 July 2009 [JCB]. Pterostichus lolo , and all other Pseudoferonina species, are probably "spring breeders" ( Bousquet 1986)-that is, they breed early in the active season, larval development takes place in late spring- summer, new adults emerge from pupal chambers in late summer-early fall, and individuals overwinter primarily as immature adults. Males collected in fall are usually immature, suggesting they may die after a single breeding season. These beetles probably vacate streambeds and floodplains in the fall so as to escape winter or spring freshets of high water. Flash floods from thunderstorms during the active season may be a major cause of mortality. The ecology of the larvae is poorly known because they are rarely seen on the surface. The extent to which larvae and adults of Pseudoferonina utilize the subterranean hyporheic zone may be substantial. As mentioned above, adults do not hesitate to crawl down into saturated streambed gravels to escape capture. The highest density of adults is often found along small creeks and reaches that have recently experienced small debris slides with rocks embedded in substantial amounts of wet organic mud. Presumably these muddy microhabitats also support the highest larval density and survival.

Dispersal power.

All known individuals are brachypterous (flightless) and restricted to the margins of a small, isolated, forested stream, so dispersal power of Pterostichus lolo adults is expected to be extremely low. Like Pterostichus shulli, Pterostichus spathifer and Pterostichus bousqueti sp. n., the geographic range of Pterostichus lolo (Fig. 5) appears to be highly restricted.

Remarks.

Based on the form of the median lobe of the male aedeagus, members of Pterostichus lolo appear to be most closely related to those of Pterostichus shulli and Pterostichus spathifer , (i.e., the shulli species-group). It is perhaps significant that both of these species, along with the more distantly related Pterostichus vexatus , occur in areas near the single known locality for Pterostichus lolo . The North Fork Clearwater River basin has the highest diversity of Pseudoferonina species.

Property ownership in the vicinity of type locality is primarily the U.S. Forest Service (Clearwater National Forest). Potlatch Corporation, Bennett Tree Farms, Inc. and the State of Idaho also have significant property ownership in this region. The primary land use impacts in this area are timber harvesting, roads, mining and off-road vehicle use. There is a large, poorly managed campground on U.S. Forest Service property along both sides of Cottonwood Creek at the type locality, with substantial off-road vehicle impacts.

Because Pterostichus lolo is known from only one, easily identifiable locality, we hope that collectors will exercise restraint when sampling at this site, and instead focus on discovering new sites for this species in the immediate vicinity.