Euconnus vetustus, Caterino, 2022

Caterino, Michael S., 2022, First report of the Euconnus Thomson subgenus Cladoconnus Reitter in the New World, represented by thirteen new Appalachian species (Coleoptera, Staphylinidae, Scydmaeninae), ZooKeys 1137, pp. 133-175 : 133

Euconnus vetustus sp. nov.

Figs 2D , 5 , 8

Type material.

Holotype ♂, deposited in FMNH: "USA: NC: Mitchell Co., 36.1038°N, 82.0809°W, PisgahNF, vi.8.2020 Grassy Ridge Bald, 6083', M. Caterino, deciduous shrub litter" / "[QR code] CLEMSON-ENT CUAC000004025" / "Caterino DNA Voucher Extraction MSC4491, Morphosp. GrB.A.336". Paratypes (4) - 2 ♀, 2 ♂: same data as type.

Other material.

(7) - NC: Graham Co., Nantahala National Forest , Huckleberry Knob, 5511 ft., 13-Oct-2020 (1 ♂) ; Haywood Co., Pisgah National Forest , Black Balsam Knob, 6072 ft., 7-May-2018 (1 ♂) ; Yancey Co., Pisgah National Forest , Devils Gap, 3813 ft., 24-Aug-2015 (2 ♂) ; ' Black Mts' (1 ♀) ; TN: Unicoi Co., Cherokee National Forest , Big Bald, 5430-5464 ft., 5-Aug-2020 & 21-May-2021 (1 ♀, 2 ♂) ; Sevier Co., Great Smoky Mountains National Park , Off Hwy 441, 4575 ft., 12-Mar-2020 (1 ♀) .

Diagnostic description.

This species is similar to the preceding species being dark in color and wing-dimorphic, and can best be distinguished by male genitalic characters. External differences, however, include smaller body size, entirely dark coloration (Fig. 8A ); head, especially crest of vertex, rounder; frons only weakly depressed between antennal bases; male and female eyes do not differ appreciably in size, both having ~ 20 ommatidia; the protibia of both sexes is shorter, widened apically, and bears conspicuously modified setae on the apical half (Fig. 8C ); male antennal club tetramerous, with the club segments slightly longer than wide (Fig. 8A ), no antennomeres bearing carinae; female antenna shorter, with club 4-segmented, club segments ca. as long as wide (Fig. 8B ); aedeagus (Fig. 2D ) with median lobe narrowed to narrowly rounded apex; rather straight parameres bear two apical setae extending just to apex of median lobe, these setae finely bent inward at apex; compressor plate symmetrical, narrow, reaching nearly to apex of median lobe; upper endophallic armature with one short curved hook, not extending beyond shoulders of tegmen, its apex blunt and distinctly fringed (at higher magnification); immediately internal to it is a rather broadly rounded thin plate (the apical margin of which is strongly sclerotized, appearing as if maybe a second opposing hook); lower endophallic armature with a long bifid process extending from deep in the basal bulb to beyond its shoulders, the inner blade thin, curving weakly upward, the outer blade longer, reaching to near apex of compressor plate, its apex finely fimbriate.

Distribution.

This species occurs over a relatively broad but disparate range, spanning the Asheville Depression, from the Unicois (Huckleberry Knob) in the southwest to the Roan Highlands and Big Bald in the northeast. So far it has not been found in the Black Mts or on Grandfather Mountain. Known occurrences are all at higher elevations, from 4575 to 6100 ft.

Remarks.

Individuals from across the broad range of this species show considerable genetic variation, and the male genitalia do show slight variation. Northern examples (Big Bald, Roan Highlands) exhibit a more strongly hooked upper endophallic process. A few specimens, from scattered localities (e.g., Smokies, Balsam Mts., and Roan Highlands), have the bi-arcuate mandibles described for European Cladoconnus . But this character varies as well; specimens from Big Bald, NC, have mandibles that are less distinctly arcuate, as well as longer and more slender. Male genitalia have been reexamined with this in mind, but no corresponding differences emerge. Further genetic work and longer series of males may justify separating some of these. Females from Devil’s Gap, NC are light in color (perhaps teneral) but match in other characters, including DNA.

The name of this species comes from the Latin for ‘old’, referring to the possibility the species has inhabited the area for a long time, as judging by its broad distribution, only distant relation to the rest of the species described here, and deep genetic divergences among populations.

Figures

Figure 2. Aedeagus A Euconnus megalops B Euconnus vexillus C Euconnus cumberlandus D Euconnus vetustus.

Figure 5. Map of collecting records for Euconnus (Cladoconnus) vexillus (squares), E. (C.) vetustus (stars), and E. (C.) adversus (circles).

Figure 8. Habitus and character photos of Euconnus vetustus A male habitus, dorsal (BBK. A. 020) B male habitus, lateral (GRB. A. 336) C SEM of protibial setae.