Dirrhagofarsus unicolor (Hisamatsu, 1960), 1935

Otto, Robert L., 2022, A new species and new records for two other exotic species of Dirrhagofarsus Fleutiaux, 1935 (Coleoptera: Eucnemidae: Melasinae: Dirhagini) in the United States, Insecta Mundi 2022 (932), pp. 1-15 : 12-14

Dirrhagofarsus unicolor (Hisamatsu, 1960)

Fig. 31–36

Dirrhagus modestus f. unicolor Hisamatsu 1960: 102 (see note below)

Diagnosis. Simple elytral apices ( Fig. 31 ) as viewed laterally will distinguish D. unicolor from D. lewisi . Presence of poorly-developed longitudinal carinae without microcombs on the frons near the compound eyes will further distinguish the eucnemid species from D. brevis new species, D. ernae , and D. modestus .

Specimens examined. Twenty specimens were available for study: CONNECTICUT: “ CONNECTICUT: New Haven ; Co., 3.6 km ESE Woodbridge ; 41.34495, −72.96683, 68 m; 28 Jun–12 Jul 2018, LFT; K. Bjarnason, BSF# 80898” (1, CMNH); “ CONNECTICUT: Fairfield ; Co., 0.9 km SE Port Chester ; 40.9961, −73.65825, 10 m; 13–27 Jun 2019, LFT; K. Bjarnason, BSF# 86404” (1, CMNH); “ CONNECTICUT: New Haven ; Co., 2.1 km NNE of Devon ; 41.220626, −73.094976, 35 m; 27 Jun–10 Jul 2019, LFT; K. Bjarnason, BSF# 87761” (1, CMNH); “CON- NECTICUT: New Haven ; Co., 2.1 km NNE of Devon ; 41.220626, −73.094976, 35 m; 10–24 Jul 2019, LFT; K. Bjarnason, BSF# 88812” (1, CMNH); MASSACHUSETTS: “ MASSACHUSETTS: Essex Co .; 1.6 km SSE West Newbury ; 42.788002, −70.983402; 45 m, 8–26 Jul 2019, LFT; A. Perkins, BSF# 87348” (1, GERP); NEW JERSEY: “ NEW JERSEY: Middlesex ; Co., 5.2 km SE Edison ; 40.4977, −74.3575, 3 m; 24 May–14 Jun 2018, LFT; S. Coachman, BSF#79374” (2, CMNH); “ NEW JERSEY: Gloucester ; Co., 4.6 km ENE Sewell ; 39.78384, −75.09519, 41 m; 5–18 Jun 2018, LFT; M.Parkinson, BSF# 79390” (1, GERP); “ NEW JERSEY: Somerset ; Co., 1.6 km N Branchburg ; 40.6014, −74.6976, 39 m; 6–22 Jun 2018, LFT; S. Coachman, BSF#79377” (1, CMNH); “ NEW JERSEY: Warren Co .; 1.2 km SE Alpha , 104 m ; 40.661464, −75.145893; 13–26 Jun 2018, LFT; P. Rockerman, BSF#79653” (3, CMNH); “ NEW JERSEY: Gloucester ; Co., 4.7 km ENE Sewell ; 39.78448, −75.09516, 41 m; 18 Jun–3 Jul 2018, LFT; M.Parkinson, BSF# 79580” (1, CMNH); “ NEW JERSEY: Passaic ; Co., 4.2 km SE Clifton ; 40.8331, −74.1264, 4 m; 21 Jun–11 Jul 2018, LFT; S.Limbachia, BSF#80501” (1, CMNH); “ NEW JERSEY: Monmouth ; Co., 1.2 km S Farmingdale ; 40.18605, −74.16875, 30 m; 26 Jun–9 Jul 2018, LFT; D.Armstrong, BSF# 80353” (1, GERP); “ NEW JERSEY: Gloucester ; Co., 4.6 km NE of Sewell ; 39.78511, −75.09613, 44 m; 4–17 Jun 2019, LFT; M. Parkinson, BSF#84919” (1, CMNH) ; “ NEW JERSEY: Warren; Co. , 1.1 km ESE Alpha; 40.68244, −75.1464; 116 m, 2–17 Jul 2019 ” / “ cross-vane panel trap; N. Aponte-Rivera; BSF# 86202” (1, CMNH) ; OHIO: “ OHIO: Erie County; 1.9 km SW Bogart ; 41.3826, −82.6706, 204 m; 23 Aug–6 Sep 2016 ” / “cross-vane panel; trap, C. Poe; BSF# 70355” (1, CMNH); RHODE ISLAND: “ RHODE ISLAND: Kent ; Co., 2.5 km E of Pontiac ; 41.73109, -71.44839; 25m, 3–17 Jul 2019, LFT; K. DiVito, BSF# 87902” (1, GERP); “ RHODE ISLAND: Providence ; Co., 3.8 km W of Quinnville ; 41.92608, −71.47851, 113 m; 5–19 Jul 2019. LFT; K. Bjarnason. BSF#87882” (1, CMNH) .

Redescription. Male. Length 4.5–5.0 mm. All examined male specimens measured 1.0 mm wide. Body subcylindrical, elongate; dorsum uniformly medium to dark reddish-brown; antennae dark reddish-brown; legs including tarsi reddish-brown; head, pronotum and elytra clothed with short, recumbent yellowish setae ( Fig. 32 ). Head ( Fig. 33 ): subspherical; integument evenly punctate, dullish except the vertex; vertex without narrow belt of microcombs; frons convex, simple; pair of longitudinal carinae on frons near compound eyes poorly-developed, without microcombs; apical margin of frontoclypeal region rounded, about 2 times wider than base; mandibles stout, bidentate, densely punctate. Antenna: weakly serriform from flagellomeres I–IX, attaining nearly 2/3 the length of the body; flagellomere I longer than II; flagellomere II slightly shorter than III; flagellomeres III– VIII each sub-equal, a little longer than wide; flagellomere IX longer than VIII. Pronotum: integument dullish, transversely rugose to closely punctate; slightly longer than wide, with moderate, sharp hind angles; lateral sides parallel-sided at basal 3/4, arcuate anteriorly at apical 1/4; disc convex; short basal medio-longitudinal carina present; base sinuous; anterolateral pronotal ridge ( Fig. 34 ) somewhat short, about 1⁄6 the length of the pronotum, directed posteroventrally; posterolateral pronotal ridge elongate, extending 3/4 the length of pronotum, slightly sinuous. Scutellar shield: quadrate, sub-triangular, shallowly punctate, setose and distally rounded. Elytra: indistinctly striate at humeri and elytral apices; striae present along elytral suture; interstices flattened; integument shiny, transversely rugose at basal 1/4 and closely punctate elsewhere; specialized punctures present at elytral apices. Legs: first tarsomere as long as the combined lengths of the remaining four on meso- and metatarsi; tibiae rounded in cross section; metatarsomeres I–III simple; metatarsomere IV excavated, emarginate; metatarsomere V elongate with simple claws. Venter: closely punctate, with short, recumbent yellowish setae; hypomeron with notosternal antennal grooves; metepisterna parallel-sided; metacoxal plates medially 3.0–6.0 times wider than laterally; last abdominal ventrite apically produced.

Sexual dimorphism. Females ( Fig. 35 ) are similar to males, but can be distinguished by their slightly shorter antennae being about 1/2 the length of the body, and stouter body. Flagellomeres are much stouter than the males, being quadrate to slightly longer than wide for flagellomeres II–VIII. Females are just as long or longer and as wide to slightly wider than males; length 4.5–6.5 mm and width 1.0– 1.5 mm.

Aedeagus ( Fig. 36 ): Basal piece longer than wide, spatulate, dorsally open, apically rounded; remaining parts elongate, basally narrow, laterally arcuate, widest medially; parameres very short, apically rounded, simple; secondary lateral lobes present, very short, shorter than parameres; median lobe very short and basally broad, apically pointed, as long as the parameres.

Distribution. This rare eucnemid species is known from Japan (Honshu and Kyushu), South Korea (Gyeonggi- Do and Seoul-Si) and taken for the first time here in the United States ( Seung et al. 2018; Otto, pers obs.). In the United States, D. unicolor was taken in Connecticut, Massachusetts, New Jersey, Ohio, and Rhode Island.

Biology. In South Korea, larvae were taken from dead, standing A. japonica trees. Many adults were reared from collected larvae as well as taken from light traps and occasionally from flight intercept traps ( Seung et al. 2018). Two specimens were taken from cross-vane panel traps in New Jersey and Ohio. Eighteen specimens were taken from Lindgren funnel traps deployed in many states across northeastern United States. Developmental stages remain undescribed.

Note. Seung et al. (2018) discovered specimens from Korea are identical to the Japanese form and were identified as Dirrhagus modestus f. unicolor Hisamatsu, 1960 . Additionally, Seung et al. (2018) determined, based on ICZN article 10.2, species names given infrasubspecific forms proposed by 1 January 1961 are available with original authority unless the description included information which showed the author intended it an infrasubspecific grouping. They determined it was not the case with the originating author and the previously ignored species was transferred to Dirrhagofarsus .

Figures

Figures 31–36. Dirrhagofarsus unicolor (Hisamatsu). 31) Elytral apices, lateral view. 32) Male, dorsal habitus. 33) Head, frontal view. 34) Pronotum, lateral view. 35) Female, dorsal habitus. 36) Aedeagus, dorsal view. (Scale: 31–36 = 1.0 mm.)