Isoplastus fossor Horn, 1880

Peck, Stewart B. & Cook, Joyce, 2013, Systematics and distributions of the genera Cyrtusa Erichson, Ecarinosphaerula Hatch, Isoplastus Horn, Liocyrtusa Daffner, Lionothus Brown, and Zeadolopus Broun of the United States and Canada (Coleoptera: Leiodidae: Leiodinae: Leiodini), Insecta Mundi 2013 (310), pp. 1-32 : 7-8

Isoplastus fossor Horn, 1880

( Fig. 2 , 17 )

Isoplastus fossor Horn, 1880: 295 ; Brown 1937b: 174; Daffner 1988: 302. Lectotype male in MCZC, type number 3191, seen; designated by Daffner 1988: 302. Type locality: District of Columbia.

Isoplastus uncus Wheeler, 1977: 77 ; Daffner 1988: 302, synonymy. Type male in MCZC, type number 32322 , seen. Type locality: Fortin de las Flores , Veracruz, Mexico .

Diagnosis. Length (pronotum + elytra) = 1.18–2.00 mm; greatest width = 0.78–1.39 mm. Reddish brown, shiny. Head finely, sparsely punctate. Antennomere 2 clearly longer and broader than 3; antennomere 7 thin, about half width of 8; apical antennomere distinctly narrower than 9. Sides of pronotum rounded, posterior angles obtuse. Pronotum finely, sparsely punctate. Elytral strial punctures coarse, finer anteriorly, separated by one diameter or less, except anteriorly; interstrial punctures minute, sparse. Metasternum strongly, densely punctate. Legs as in generic diagnosis. Abdominal sternites III–VIII each with transverse row of small punctures on apical half; sternite III rugose. Median lobe of aedeagus ( Fig. 2 ) broad, angled about 90 degrees in lateral view; paired apices each divided at tip. Parameres ( Fig. 2 ) extend beyond apex of median lobe. Armature of inverted internal sac as in Fig. 2 .

Distribution. North American distribution ( Fig. 17 ): CANADA. ONTARIO, QUEBEC. UNITED STATES. ALABAMA, ARKANSAS, ARIZONA, DISTRICT OF COLUMBIA, FLORIDA, GEORGIA, INDIANA, KENTUCKY, LOUISIANA, MICHIGAN, MISSISSIPPI, NORTH CAROLINA, OKLAHOMA, SOUTH CAROLINA, TEXAS, VIRGINIA. Extra-limital distribution: Mexico (doubtful, see Remarks).

Previously recorded in North America ( Horn 1880, Brown 1937b, Daffner 1988) from: CANADA. ONTARIO. Arnprior. QUEBEC. Aylmer. UNITED STATES. MICHIGAN. Detroit. DISTRICT OF COLUMBIA.

Seasonality. Adults have been collected from February to November, and mostly in June to August, with the early and late season records from southerly locations in Florida and Texas.

Bionomics. Adults have been collected in habitats ranging from open pine forest and juniper thicket to mature mixed and bottomland beech-magnolia forest. Taken mostly by flight intercept traps but also by sweeping and ultraviolet light traps.

Remarks. We question the above synonymy and think it needs re-examination. We suspect that I. uncus is actually a valid species, and we have seen several undescribed species of Isoplastus from Mexico and southward.

New material examined. We have seen 434 specimens from the following localities. CANADA. ONTARIO. L3C6 Wolford Township, 44° 52’03”N, 75°43’50” W. Tilbury. UNITED STATES. ALABAMA. Dale Co. Ft. Rucker Military Reservation. Jefferson Co., Hoover. ARKANSAS. Little Rock Co., Little Rock. Logan Co., Magazine Mountain. ARIZONA. Cochise Co., Chiricahua Mts., Turkey Creek. FLORIDA. Alachua Co., Gainesville. 10 km SW Gainesville. Jackson Co., Marianna, Florida Caverns State Park. Sneads, Three Rivers State Park. Leon Co., 20 mi N Tallahassee, Tall Timbers Station. Liberty Co. 14 km N Bristol, Appalachicola Bluffs and Ravines Preserve. Suwanee Co., Suwanee River State Park. GEORGIA. Greene Co., Oconee National Forest. INDIANA. Tippecanoe Co. KENTUCKY. Edmonson Co., Mammoth Cave National Park. Metcalfe Co., 0.5 mi NE East Fork. LOUISIANA. Catahoula Parish, Walters, Catahoula National Wildlife Refuge. Grant Parish, 18 km N Alexandria, Stuart Lake Camp. Natchitoches Parish, Kisahatchie Bayou. West Feliciana Parish, Feliciana Preserve. MISSISSIPPI. Pontotoc Co., 32 km SW Tupelo, Tockshish. NORTH CAROLINA. Northampton Co., 7 km S Jackson. OKLAHOMA. Latimer Co., Red Oak. Wagoner Co., 3 mi W Wagoner. SOUTH CAROLINA Anderson Co., Pendleton. Oconee Co., 12 mi NE Walhalla. Pickens Co., Calhoun. TEXAS. Bell Co., 1 km W Youngsport. Brazos Co., Lick Creek Park, College Station. Ellis Co., 3.6 mi NW Italy. Hays Co., 6 mi NW Dripping Springs. 6.5 mi SW Hunt. Kerr Co., Kerrville. Montgomery Co., 4.5 mi N Montgomery. Polk Co., 20 km S Coldspring. Sabine Co., 9 mi E Hemphill, Beech Bottom. San Augustine Co., Piney Woods Conservation Center. San Jacinto Co., 5 km S Coldspring. Shelby Co., 20 km SE Shelby. Tyler Co., 5 mi E Spurger. Wood. Co., Godwin Woods, 3.5 mi SW Hainesville. VIRGINIA. Fredericksburg. Warren Co., 4 km NNW Linden.

Figures

Figure 17. North American distribution of Isoplastus fossor (black circles), I. floridanus (black triangles).

Figures 1–6. Aedeagi, dorsal, of Cyrtusa and Isoplastus species. 1) Cyrtusa subtestacea. 2) Isoplastus fossor. 3) I. floridanus. 4) L. luggeri. 5) L. nigriclavis. 6) L. stephani. Scale line = 0.3 mm.