Dirrhagofarsus ernae Otto, Muona

Otto, Robert L., Muona, Jyrki & Mcclarin, Jim, 2014, Description of Dirrhagofarsus ernae n. sp. with a key to the known Dirrhagofarsus species (Coleoptera: Eucnemidae), Zootaxa 3878 (2), pp. 179-184 : 180-183

Dirrhagofarsus ernae Otto, Muona , and McClarin, new species

( Figures 1–5 )

Diagnosis. Within North American Dirhagini , characterized by lateral carinae on frons combined

with simple elytral apex.

Description. Adult. Holotype male. Length 5 mm; greatest width 1.5 mm. Color black with anterior pronotal margin red-brown. Form subcylindrical, moderately elongate and tapering towards apex ( Fig. 1 ), dorsum clothed with vestiture of short, yellow decumbent hairs. Head subspherical with convex, smooth, shiny and punctate frons. Lateral frontal keels sharp, short, slightly bent and covered with micro-combs, giving a silvery appearance. Vertex with undulating, complete belt of micro-combs. Mandibles stout, bidentate and densely punctate. Antennae redbrown, evenly colored and longer than half the length of the body. Antennomere 3 about 1.4 times as long as 4, antennomeres 4–10 subtriangular and elongated. Antennomere 11 at least 2 ½ times longer than wide. Pronotum slightly transverse and subquadrangular. Anterior portion of pronotum slightly convex. Surface shiny, with moderately dense punctures; small and slightly spaced, sides parallel. Disc of pronotum with a slight depression on both sides. Anterior lateral pronotal carinae reach about ¼ the length of pronotum, while the posterior lateral pronotal carinae ( Fig. 2) reach more than ¾ the length of pronotum. Notosternal antennal grooves shiny and smooth. Inner ridge of antennal grooves obliterated on apical half. Scutellum densely punctate, subtriangular and narrowly rounded at end. Elytra have strongly punctate striae and interspaces. Punctures are partly confused, especially basally. Interspaces are convex at the humeral region and largely flat elsewhere on elytra. Legs redbrown in color. Tibiae rounded in cross section. Lateral surfaces of meso- and meta-tibae with single spines. Claws simple. Tarsomere 4 excavate emarginate. Tarsomeres 1 to 3 simple, protarsomere 1 without sex-comb. Tarsomere 1 as long as the preceding four combined in meso- and meta-tarsi. Metatarsomere 2 twice as long as third and as long as fifth.

Aedeagus similar to that of D. attenuatus (see Burakowski 1991), but secondary lateral lobes shorter, lateral lobes apically sharper and median lobe slightly shorter ( Fig. 4). Aedeagus also similar to that of D. modestus ( Fig. 5), but secondary lateral lobes reach nearly the apex of the aedeagus in D. modestus and the apical part of the organ is proportionately smaller and wider, the basal part elongated and narrow. The flagellum in D. ernae is slender and with small hooks evenly distributed towards the apex, whereas in D. modestus it is medially wide and the hooks are more numerous and absent from the apical region.

We have examined 68 adult paratypes. Nine larvae and three pupae were also studied. Females are on average slightly larger than males. Their antennae are stouter, not quite reaching half the length of the body, antennomere 11 being about two times longer than wide ( Fig. 3). The pronotum is mostly densely punctate to rugose, slightly dullish. The posterior lateral pronotal carina is shorter than in the males, reaching about 2/3 the length of the pronotum. The anterior lateral carina is slightly more acutely angled in the females than in the males. This pronotal dimorphism seems to be true for D. modestus and D. attenuatus as well. The length and height of median carina near the posterior end of the pronotum is variable, many specimens exhibiting a small, shallow to nearly indistinct median carina. Color intensity along the anterior margin of pronotum is slightly variable, but only a few males show a uniform black pronotum, typical of D. modestus .

Holotype: Ohio, Hamilton Co., male, “OH: Hamilton Co., Cincinnati, Mount Airy Forest, May 17, 1998, Eric Eaton coll”. Paratypes: Alabama, Dale Co.: 1 example, “Ala. Dale Co., Ft. Rucker Mil. Res., sugar bait, 1–7 May 1999, R. Turnbow”; 1 example, “Ala. Dale Co., Ft. Rucker Mil. Res., 5–12 may 2009, R. Turnbow, manuka oil baited Lindgren funnel trap”. Missouri, DeKalb Co.: 1 example, “MO: DeKalb Co., 13.4 mi. Cameron, 25 May 2007, R. Turnbow”; Stone Co.: 1 example, “MO: Stone Co., Ashe Juniper Natural Area, 4.0 mi. N Hwy 86 on JJ, T22N R22W sec. 20, T.C. MacRae, 00-90b: emerged. 16–23.v.2001, ex. 1–3" diameter dead branch Acer saccharum L., coll. 17.ix.2000 ”. New Hampshire, Hillsborough Co.: 26 examples (14 adults, 9 larvae and 3 pupae), “NH: Hillsborough Co., Nashua, 10 Jan, 2007, Jim McClarin, Reared from larvae in white rotten aspen”. Ohio, Hamilton Co.: 6 examples, “OH: Hamilton Co., Cincinnati, Mount Airy Forest, May 17, 1998, Eric Eaton Coll.”; 1 example, “OH: Hamilton Co., Cincinnati, Price Hill, June 24, 1998, Eric Eaton coll.”; Preble Co.: 2 examples, “OH: Preble Co., Camden, 6 June 2001, M. Ulyschen”; Butler Co.: 1 ex., “OH: Butler Co., Oxford, 6 July 2001, M. Ulyschen”. Pennsylvania, Westmoreland Co.: 2 examples, “ USA, PA, Westmoreland Co., 10 KM S. Ligonier, Powdermill Nat. Res., 29 VI 1996; dead trees and fungus at night; D.A. Pollock”. Virginia, Montgomery Co.: 3 examples, “VA: Montgomery Co., ca 3 km SE Ellett, off Rt. 641, Slaughterpen Hollow, DenCrk, 10 June 2001, J.C. Ludwig UV”; Floyd Co.: 1 example, “VA: Floyd Co., Buffalo Mtn., 3500 feet, 3500–3900', 20 June 2001, S.M. Roble UV”; Bath Co.: 1 example, “VA: Bath Co., Warm Springs Mtn., Jct. Ridgecut Rd & Rd to Trappers Lodge, 14 June 1999, old growth nr. clear cut, J.C. Ludwig UV”; 1 example, “VA: City of Richmond, 9404 Derbyshire Road, Apr–Aug 1995, W.H. Mitchell”. Wisconsin, Dane Co.: 1 example, “NG 14113, United States of America, Wisconsin, Dane County, Madison, Eagle Heights, (300 m), 43º 05' N 89º 26' W, 12.VII.2003, Gompel N. Leg.”; La Crosse Co.: 1 example., “WI: La Crosse Co., West Salem, Site 8, N44º 3.589' W91º 4.430', root sever, Lindgren trap, 29 June 2004, Robert Murphy”; 1 ex., “WI: La Crosse Co., West Salem, Site 3B, N44º 4.082' W91º 4.575', root sever, flight intercept trap, 26 July–9 August 2004, Robert Murphy”; 1 example., “WI: La Crosse Co., West Salem, Site 8, N44º 3.589' W91º 4.430', root sever, flight intercept trap, 26 July–9 August 2004, Robert Murphy”; 1 example., “WI: La Crosse Co., West Salem, Site 2, N44º 3.411' W91º 3.430', pkt control, flight intercept trap—inside, 23 June 2005, Robert Murphy”; 2 examples., “WI: La Crosse Co., West Salem, Site 1, N44º 3.778' W91º 4.332', pkt control, flight intercept trap—inside, 7 July 2005, Robert Murphy”; 2 examples., “WI: La Crosse Co., West Salem, Site 5, N44º 3.963' W91º 4.521', root sever, flight intercept trap—outside, 7 July 2005, Robert Murphy”; 1 example., “WI: La Crosse Co., West Salem, Site 2, N44.06296º W91.07220º, pkt control, flight intercept trap—inside, 21 July 2005, Robert Murphy”; 1 example., “WI: La Crosse Co., West Salem, Site 5, N44.06605º W91.07220º, root sever, flight intercept trap—outside, 21 July 2005, Robert Murphy”; Milwaukee Co.: 1 example., “NG 14074, United States of America, Wisconsin, Milwaukee County, South Milwaukee, Grant Park, Seven Bridges, 42º 55' N 87º 50' W, Woods, 2.VII.2003, Gompel N. Leg.”; Sauk Co.: 1 example., “WI: Sauk Co., Gatshall property, N43º 4.765' W89º 34.576', asystematic control, flight intercept trap—inside, 16 June 2005, Robert Murphy”; 1 example., “WI: Sauk Co., Bakken's Pond, Site 2, N43º 10.830' W90º 9.205', pkt. control, flight intercept trap—out, 16 June 2005, Robert Murphy”; Walworth Co.: 1 example., “WI: Walworth Co., Kettle Moraine St. Forest, N42º 49.551' W88º 36.583', asystematic control, flight intercept trap—inside, 15 June 2005, Robert Murphy”; 2 examples., “WI: Walworth Co., Kettle Moraine St. Forest, N42º 49.610' W88º 36.471', root sever, flight intercept trap—outside, 28 June 2005, Robert Murphy”; 1 example., “WI: Walworth Co., Kettle Moraine St. Forest, N42º 49.551' W88º 36.583', asystematic control, flight intercept trap—inside, 28 June 2005, Robert Murphy”; Waukesha Co.: 1 example., “WI: Waukesha Co., Kettle Moraine St. Forest, N42º 51.574' W88º 29.781', pkt control, Lindgren Trap, 9 June 2004, Robert Murphy’; 1 example., “WI: Waukesha Co., Kettle Moraine St. Forest, N42º 54.616' W88º 27.891', asystematic control, flight intercept trap—inside, 15 June 2005, Robert Murphy”; 2 examples., “WI: Waukesha Co., Kettle Moraine St. Forest, N42º 54.574' W88º 29.781', pkt control, flight intercept trap—out, 15 June 2005, Robert Murphy”; 1 example., “WI: Waukesha Co., Kettle Moraine St. Forest, N42º 51.574' W88º 29.781', pkt control, flight intercept trap—inside, 15 June 2005, Robert Murphy”; 1 example., “WI: Waukesha Co., Kettle Moraine St. Forest, N42º 54.840' W88º 28.088', root sever, flight intercept trap—out, 15 June 2005, Robert Murphy”; 1 example., “WI: Waukesha Co., Kettle Moraine St. Forest, N42º 49.551' W88º 36.583', asystematic control, flight intercept trap—outside, 28 June 2005, Robert Murphy”; 4 examples., “WI: Waukesha Co., Kettle Moraine St. Forest, N42º 54.616' W88º 27.891', asystematic control, flight intercept trap—inside, 29 June 2005, Robert Murphy”; 1 example., “WI: Waukesha Co., Kettle Moraine St. Forest, N42º 54.840' W88º 28.088', root sever, flight intercept trap—inside, 29 June 2005, Robert Murphy”; 1 example., “WI: Waukesha Co., Kettle Moraine St. Forest, N42º 54.840' W88º 28.088', root sever, flight intercept trap—outside, 29 June 2005, Robert Murphy”; Waupaca Co.: 1 example., “WI: Waupaca Co., J. Baker property, Site 3, N44º 18.805' W89º 6.238', asystematic control, flight intercept trap—inside, 22 June 2005, Robert Murphy”.

The holotype male and one female paratype are deposited at the US National Museum in Washington DC. Further paratypes are deposited in the American Museum of Natural History, the UW Entomology Museum (UW- Madison), the Insect Research Collection (South Dakota State University), the Field Museum of Natural History in Chicago, the Royal Ontario Museum in Quebec, the Finnish Museum of Natural History, Bohart Museum of Entomology (UC-Davis), Florida State Collection of Arthropods (Gainesville) and Virginia Museum of Natural History as well as the collections of the authors, Eric Eaton, Ed Riley, Ted MacRae and Nicolas Gompel.

Etymology. Dirrhagofarsus ernae is named in honor of the senior author’s grandmother, Erna (Karstedt) James who passed away in 1999.

Larva. ( Figs. 6 –11)

Mature larvae ( Fig. 6). Length 14–16 mm, width 1.0– 1.2 mm. Body subcylindrical, near parallel-sided, pro- and meso-thorax wider than remaining segments, cream-yellow in color with head, prothoracic scleromes and posterior end of ninth abdominal segment dark brown. Head dorsoventrally flattened, broadly subtriangular, prognathus and exerted from prothorax. The sclcerotized cephalic discs form a compact structure with lateral toothlike projections ( Figs. 7, 8). Dorsal cephalic disc subtrapezoidal with longitudinal furrows on either side of midline. Longitudinal furrows converge anteriad, forming a small trapezoidal ridge with basal median carina. Ventral cephalic disc pentagonally shaped and with a small single raised carina. Anterior portion of head heavily sclerotized near mandibles. Mandibles heavily sclerotized, oval, longer than wide, deeply bifid, fused to head, resting in mesal acumination of head capsule. Labium weakly chitinized, retractile, with three segments. Labial palps slightly longer with three segments. Visible ligula, mala, lacinia and galea absent. Hypostomal rods also absent. Antennae minute, arising between first and second lateral projections. Basal segment about as long as wide, second segment of equal length, but narrow, with three apical setae. Sensory papillae well developed, about as long as second antennal segment. Prothorax slightly longer than metathorax and abdominal segments subequal to mesothoracic segment, metathorax being shortest of all. Dorsally, near anterior end, a pair of horizonal lineal scleromes extend from lateral sides to mesal ecdysial line, diverge and run length of pronotum. A small circular sclerome present near anterior end of prothorax, laterad of each narrowed sclerome.

Ninth abdominal sternite (Fig. 10) heavily sclerotized with prominent semi-circular ring of asperities above anal region. Smaller asperities form oblong, oval ring around the anus and extend to each end of larger spicules. Ninth abdominal tergite (Fig. 9) with well-developed microtrichial patch. Posterior margin of ninth segment sparsely punctate with shallow furrows, strongly sclerotized. Spiracles are annular biforous.

The arrangement of the microtrichial patches and areoles on dorsum are shown in Fig. 11.

The detailed description of the larva of the Palaearctic Dirrhagofarsus attenuatus (Mäklin) ( Burakowski, 1989) allows a useful comparison of the larval types.Although superficially similar, the larvae differ in many details. The strongly sclerotized apex of the 9th segment is pointed and nearly triangular in D. ernae , less sclerotized and abruptly cut off in D. attenuatus . The head capsule of D. attenuatus is longitudinally grooved, especially strongly dorsally, whereas in D. ernae it is clearly smoother. The ventral supporting rods on the prothorax have long laterally diverging cranial tips in D. ernae , whereas in D. attenuatus the cranial tips of these rods are very short.

Additional information. The first larva of this species was collected independently of senior authors’ adult finds on January 7, 2007 by J. McClarin in Nashua, New Hampshire, USA. It was found in a fairly dry, long-dead, 1.5 m trunk section of Populus that had broken away from the tree several meters off the ground and become caught in a tangle of Celastrus (bittersweet vines), suspended about 1.5 m off the ground. Over 20 more larvae from 6 mm to 18.5 mm long were collected January 10th in a return visit to the same trunk section, over half of which was softened by white-rot fungus. The larvae were aligned with the wood grain and many were doubled back in their burrows with head in close proximity to its terminal tergite. In attempt to rear an adult for identification, McClarin placed a majority of freed larvae in a sealed plastic container together with small scraps from the Populus trunk section. Some larger wood chunks were also included in hope they contained additional larvae. While most of the freed larvae did not establish new burrows in the soft wood, many had pupated by Feb. 3 and the first adult eclosed on February 9, followed by many more in later days. Because the species proved unrecognizable from photos, first larvae then adults and pupae were preserved and sent to Muona for identification and subsequent DNA sequencing. Muona had already heard from Otto about his discovery of an apparent undescribed species, and he and Otto eventually determined through their independent finds that they were of the same species. Many photos of larvae, pupae and adults of this species may be seen in the Dirrhagofarsus section of bugguide.net: http://bugguide.net/node/view/114573/bgimage.

FIGURE 9. Dirrhagofarsus ernae n. sp., larva, 9th abdominal segment, dorsal (upper) view. FIGURE 10. Dirrhagofarsus ernae n. sp., larva,, 9th abdominal segment, ventral (lower) view. FIGURE 11. Dirrhagofarsus ernae n. sp., larva, position of microtrichial patches and areoles on dorsum.

Figures

FIGURE 1. Dirrhagofarsus ernae n. sp., male. Scale 5 mm.