Elonus gruberi Gompel, 2017

Gompel, Nicolas, 2017, A review of North American Elonus species, with description of E. gruberi n. sp. (Coleoptera: Tenebrionoidea: Aderidae), Zootaxa 4338 (3), pp. 533-545 : 539-542

Elonus gruberi Gompel , n. sp.

( Figures 1b,c ; 2b,i,o; 3c,j,q; 4a,b,j; 5)

Elonus gruber i n. sp., male holotype deposited in the Nicolas Gompel private collection

Etymology. The species is named after my friend Jeff Gruber, in appreciation of his tremendous efforts to collect and share Aderidae and other little brown beetles across Northern America.

Type locality. United States, Wisconsin, Madison, Eagle Heights [43°05’06”N 89°26’03"W].

Distribution. United States (Alabama, Arkansas, Delaware, Indiana, Iowa, Massachusetts, Mississippi, New Hampshire, Ohio, Texas, Pennsylvania, Wisconsin).

Notes. (i) Given the presence of several specimens of Elonus gruberi n. sp. in a series identified as Elonus basalis , I examined the female holotype of Elonus princeps , a junior synonym of Elonus basalis ( Werner, 1990) . I have remounted it, and I confirm that it should be assigned to Elonus basalis . In particular, its elytra have a postmedian band of whitish pubescence characteristic of Elonus basalis .

(ii) Elytral markings: these marks form a solid basal stripe, without a notch at the scutellum in Elonus hesperus Werner, 1990 . They also form an uninterrupted basal stripe in most specimens of Elonus basalis ( LeConte, 1855) , which is occasionally attenuated towards the scutellum (but the pubescence and other morphological characters are distinct from Elonus hesperus Werner, 1990 ). The majority of Eastern specimens of E. gruberi n. sp. have 2 separate blotches of orange pigmentation. In specimens from Texas (San Patricio County population) and one specimen from Delaware the orange pigmentation extends towards the suture in a M-like shape pattern.

(iii) Shape of male sternal plate appears consistent within this species and different from that of other species, but these variations are difficult to describe and the character was not retained for species separation.

(iv) The structure and shape of the male genitalia is stable in E. gruberi n. sp., and sufficient to separate it from all other North American species, with the exception of E. hesperus Werner, 1990 , where external characters should be used.

Description. ( Figure 1b,c ). Length: 2.6–3.4 mm, body elongate, sides subparallel, overall color matte dark, with orange markings on elytra, covered with dense pubescence. Body pubescence double, with long erect bristles originating from punctures with interspersed short whitish setae.

Head. Transverse, as wide as, or slightly wider than pronotum; covered with dense punctation and erect black pubescence; head tegument entirely black; palpi orange.

Antennae ( Figure 2i, o ). Black, covered with dense, erect pubescence, pointing towards antennal apex. Antennomeres 2–7 (♀) or 2–10 (♂) quadrate or slightly longer than wide; sexual dimorphism: male antennae longer, slenderer at apex, with apical antennomere subequal in length to antennomeres 8–10 ( Figure 2i ); female antennomeres progressively increasing in width from base to apex, with apical antennomere subequal to penultimate antennomeres ( Figure 2o ).

Pronotum. Length 0.5–0.7 mm. Subquadrate, base wider than apex, sides parallel along posterior half, then converging toward apex; maximum width at mid-length between base and apex; densely punctated and pubescent. Width about 60% of elytral width.

Elytra. Length 1.8–2.2 mm. Width 0.9–1.2 mm. Dark with orange markings in humeral region, rarely continuous in scutellar region ( Figure 4a, b ). Elytral punctation dense and strong, no different from other North American species. Elytral pubescence uniform. Long bristles arising from punctation yellow, recumbent, inconspicuous. Shorter pubescence sparse, yellowish, only visible at high magnification ( Figure 4j ). Elytra suture finely lined-up with white pubescence.

Legs. Femorae and tibiae brown, sometimes with ill-defined reddish zones toward base. Tarsi reddish to orange. No notable modifications in females, strongly differentiated in males. Male protibiae slightly bent inwards at apex; male mesotibiae strongly and regularly bowed (as much as in Elonus hesperus Werner, 1990 ) ( Figure 3j ); male metafemora with ample brush on underside ( Figure 3q ) and large excavation at base ( Figure 3q , arrowhead).

Abdominal sternites. Sexually dimorphic. Evenly convex in females, strongly modified in males with an elevated sternal plate arising from sternites 2–5 and fringed with dense yellow pubescence ( Figure 3c ).

Male genitalia. Stocky, lateral margins subparallel, only convergent in apical fourth. Aedeagus long, retractile, often everted in killed specimens ( Figure 2b ), apex asymmetrically acuminate.

Type material: USA. Alabama: Baldwin County, Weeks Bay NER reserve, mixed forest near estuary, black light and MV lamp (JA MacGown leg.) 4.VIII.2000 (1 ♂, MEMC), (TL Schiefer leg.) 25.VI.2001 (1 ♂, MEMC); Lawrence County, Prairie Grove Glade, Cedar glade, beating trees and shrubs (TL Schiefer leg.) 25.V.2004 (1 ♂, 1 ♀, MEMC); Monroe County, 1 mi. S Claiborne Dam, beating trees and shrubs (TL Schiefer leg.) 30.V.1995 (1 ♀, MEMC); Arkansas: Garland County, Royal, Camp Clearfork, UV light traps (B Baldwin leg.) 19.VI.2006 (1 ♀, UNHC), 19.VI.2008 (1 ♂, UNHC), 21.VI.2009 (1 ♂, UNHC), 23.VI.2009 (1 ♂, UNHC), 12.VI.2010 (2 ♂, UNHC); Polk County, Mena, UV light traps (B Baldwin leg.) 10.VIII.2006 (1 ♂, UNHC), 12.VI.2009 (1 ♂, UNHC), 8.VI.2010 (1 ♀, UNHC); Pulaski County, Little Rock, malaise trap (B Baldwin leg.) 15.VI.2003 (1 ♀, UNHC), 9.VIII.2003 (1 ♂, UNHC); Delaware: Kent County, 0.5 mi. N of Dinahs Corner, at incandescent light (RFC Naczi leg.) 12.VIII.2002 (1 ♂, UNHC); Illinois, Mason County, Long Branch Sand Prairie Nature Reserve, Malaise trap #1 to ethanol (K Zeiders and B Fuller leg.) 11.IX.1997 (1 ♂, WIRC); Indiana: Tippecanoe County, Lafayette, UV light (NM Downie leg.) 28.VII.1985 (1 ♀, UNHC); Iowa: Woodbury County, Southwood Conservation Area (SM Clark leg.) 7.VII.1997 (1 ♀, UNHC); Massachusetts: Middlesex County, Framingham (CA Frost leg.) 19.VII.1950 (1 ♂, MCZC); Norfolk County, Grape Island (S Sands & J Novak leg.) 9.VII.2008 (1 ♀, MCZC); Plymouth County, Bumkin Island (M Wheat leg.,) 19.VII.2006 (1 ♀, MCZC), 20.VII.2006 (1 ♂, MCZC); Mississippi: Oktibbeha County, Craig Springs, pitfall trap peripheral to cultivated cotton (GL Snodgrass leg.) 3.X.1979 (1 ♀, MEMC); New Hampshire: Strafford County, Dover, Bellamy road, 3.2 km S Dover, sweep red oak (DS Chandler leg.) 16.VII.2011 (1 ♂, UNHC); Strafford County, Durham, 4 mi. W Durham, Malaise trap (RM Reeves leg.) 1.VIII.1982 (1 ♀, UNHC), Window trap (RM Reeves leg.) 29.VIII.1982 (1 ♂, UNHC); Strafford County, Durham (WJ Morse leg.) 25.VII.1985 (1 ♂, UNHC); Ohio: Cuyahoga County, Fairview Park, MacBeth Avenue, UV trap (HJ Lee leg.) 25.V.2006 (1 ♂, UNHC); Texas: San Patricio County, Welder Wildlife Refuge, adjacent to Arkansas River, Forest/savanna, Beaten from branches of Ulmus crassifolia Nutt. (JP Gruber leg.) 17.IV.2014 (10 ♂, 8 ♀, NGPC); Pennsylvania: (FC Bowditch leg.) (1 ♂, MCZC); Wisconsin: Dane County, Madison, Eagle Heights, attracted by light (N Gompel leg.) 30.VI.2002 (1 ♀, NGPC), 1.VII.2002 (1 ♂, NGPC), 5.VII.2002 (1 ♀, NGPC), 6.VII.2002 (6 ♂, including holotype, NGPC), 7.VII.2002 (1 ♂, 1 ♀, NGPC), 12.VII.2002 (1 ♂, NGPC), 19.VII.2003 (1 ♂, NGPC), 15.VII.2004 (1 ♀, NGPC); Grant County, Cassville Bluffs SNA, mixed hardwood forest, sweeping foliage near path, afternoon, clear (JP Gruber leg.) 18.VII.2003 (1 ♂, 3 ♀, WIRC; 1 ♀, NGPC); La Crosse County, Coulee Experimental State Forest, hardwood dominated forest, hardwood tree, beaten from branches of Tilia americana L. or Carya sp. (JP Gruber leg.) 18.VII.2014 (3 ♂, 1 ♀, NGPC); Sauk County, Spring Green Preserve SNA, (220 m), dry-mesic southern forest, swept from foliage near path (JP Gruber leg.) 13.VII.2003 (1 ♂, NGPC), 1.VIII.2003 (1 ♂, 1 ♀, WIRC), 19. VIII.2 0 0 9 (1 ♂, WIRC); Sheboygan County, Kohler-Andrae State Park, mixed coniferous/hardwood forest, beaten from branches of hardwood tree (JP Gruber leg.) 13.VIII.2012 (2 ♂, WIRC). Imprecise locality: “Am. Bor” (likely for America Borealis) VII.1874 (1 ♂, MNHN).

Figures

FIGURE 1. Habitus of Elonus species in dorsal view. a, Elonus basalis (LeConte), ♂, from Wisconsin. b, Elonus gruberi n. sp., ♂ holotype, from Wisconsin. c, Elonus gruberi n. sp., ♀, from Wisconsin. d, Elonus simplex Werner, ♂, from Arizona (paratype). e, Elonus hesperus Werner, ♂, from Mississippi. f, Elonus hesperus Werner, ♀, from Mississippi. g, Elonus excavatus Werner, ♂, from Arizona (holotype). h, Elonus chisosensis Werner, ♂, from Arizona (paratype). d, Elonus nebulosus (LeConte), ♂, from Texas.

FIGURE 2. Male genitalia and antennae of Elonus species. a – g, male genitalia in dorsal view. a, Elonus basalis (LeConte), from Wisconsin; b, Elonus gruberi n. sp., ♂ holotype, from Wisconsin; c, Elonus hesperus Werner, from Mississippi; d, Elonus nebulosus (LeConte), from Texas; e, Elonus simplex Werner, from Arizona (paratype); f, Elonus excavatus Werner, from Arizona (holotype); g, Elonus chisosensis Werner, ♂, from Arizona (paratype). h – l, n, male right antenna in dorsal view. h, Elonus basalis (LeConte), from Wisconsin; i, Elonus gruberi n. sp., holotype, from Wisconsin; j, Elonus hesperus Werner, from Mississippi; k, Elonus nebulosus (LeConte), from Texas; l, Elonus simplex Werner, from Arizona (paratype); n, Elonus chisosensis Werner, from Arizona (paratype); m, right antenna of Elonus excavatus Werner, ♂, from Arizona (holotype); o, left antenna of Elonus gruberi n. sp., ♀, from Wisconsin.

FIGURE 3. Abdominal sternites and leg morphology of male Elonus species. Abdominal sternites in ventral view (a – g) (note the variable anterior extension of the golden pubescence (white arrows )), tibiae of mesothoracic legs in dorsal view (h – n) and femora of metathoracic legs in ventral view (o – u) (note the presence of a proximal excavation in some species (empty arrowheads )). a, h, o, Elonus nebulosus (LeConte), from Texas; b, i, p, Elonus basalis (LeConte), from Wisconsin; c, j, q, Elonus gruberi n. sp., ♂ holotype, from Wisconsin; d, k, r, Elonus hesperus Werner, from Mississippi; e, l, s, Elonus simplex Werner, from Arizona (paratype); f, t, Elonus excavatus Werner, from Arizona (holotype); m, Elonus excavatus Werner, from Arizona (paratype): note the kink in the mesotibiae (black arrowhead); g, n, u, Elonus chisosensis Werner, ♂, from Arizona (paratype).

FIGURE 4. Elytral pigmentation and pubescence of Elonus species. a – d, basal orange pattern variation. a, Elonus gruberi n. sp., ♂ holotype, from Wisconsin; b, Elonus gruberi n. sp., ♂ from Texas; c, Elonus basalis (LeConte), ♂, from Wisconsin; d, Elonus hesperus Werner, ♂, from Mississippi. e – j, elytral pubescence. e, Elonus chisosensis Werner, ♂, from Arizona (paratype); f, Elonus hesperus Werner, ♂, from Mississippi; g, Elonus excavatus Werner, from Arizona (paratype); h, Elonus basalis (LeConte), ♂, from Wisconsin; i, Elonus simplex Werner, from Arizona (paratype) (note the lateral patches of short white recumbent hairs (white arrows); j, Elonus gruberi n. sp., ♂ holotype, from Wisconsin.