Neuroctenus pseudonymus Bergroth, 1898

Swanson, Daniel R., Taylor, Steven J. & Heads, Sam W., 2017, Nine true bugs (Heteroptera) newly-discovered in Illinois, Zootaxa 4269 (4), pp. 571-585 : 572

Neuroctenus pseudonymus Bergroth, 1898 and Nannium pusio Heidemann, 1909 ( Aradidae : Mezirinae ).

During the fall of 2014, a single adult male aradid was unknowingly collected in a leaf litter sample outside Brasher Cave (Pope County). Organisms were separated from leaf litter, soil, and detritus into ethanol via Berlese funnel, and the aradid was discovered in the subsequent sort and identified as Neuroctenus pseudonymus ( Fig. 1 ), a species previously unknown in Illinois. The specimen bears the following label data : ILLINOIS: Pope Co.: Brasher Cave : entrance: leaf litter, 14 August 2014, coll. SJTaylor, MLNiemiller & SDCinel, Sample Number: 1201, Lot Number Shw 0532, det. D. R. Swanson 2015 [1 male] . The entrance to Brasher Cave lies in a small, shallow, thinly-wooded sinkhole ( Fig. 10 ) in an upland deciduous (oak) forest. The forested setting results in copious accumulations of leaf litter in and around the cave entrance. The specimen, now dried and point-mounted, has been vouchered in the Illinois Natural History Survey Insect Collection ( INHS Insect Collection 809,670).

A search for corroborative material in that collection revealed three additional specimens with the following label data: ILLINOIS: [Calhoun Co.], Hardin , 5–9 June 1932, coll. H. L. Dozier, det. D. R. Swanson 2016, INHS Insect Collection 777,271 [1 female] ; [Champaign Co.], Urbana, University Woods, from soil cover in woods, 15 Oct. 1933, M. D. Farrar, det. P. D. Ashlock 1938, det. D. R. Swanson 2016, INHS Insect Collection 777,274 ; Union Co., Pine Hills, under flat stone near swamp, 20 March 1988, S. Taylor, det. S. Taylor 1988, INHS Insect Collection 775,584 [1 female, figured].

Sparsely mentioned in the literature, Ne. pseudonymus is easily recognized among the six Nearctic species of the genus by the ovate form of the body and the folds present on the seventh tergite. Heidemann (1904) reported this species from under the bark of fallen chestnut ( Castanea sp.). McClure (1932) documented prenatal care in this species. Froeschner (1988a) recorded the species from Washington, D.C. , Indiana , North Carolina , Ohio , Tennessee, and Texas, and Kormilev (1982) added Maryland and Virginia . More recently, Taylor & Gil (2009) recorded Ne. pseudonymus from Louisiana . The current known distribution of the species north of Mexico is summarized in Fig. 15 .

Also found in the INHS was a single adult female of Nannium pusio . The specimen ( Fig. 2 ) bears the following label data: ILLINOIS: [St. Clair Co.], Edgemont, debr. in tree, 16 September 1943, W. E. Snow, det. D. R. Swanson 2015 , INHS Insect Collection 775,583 [1 female] ( INHS). Although not "freshly caught", the specimen is conveniently reported here as a new state record to provide a more complete picture of the Mezirinae of Illinois . Nannium pusio is easily separated from other mezirines by the small size and trisinuate posterior margin of the pronotum. Until now, it has only been recorded from the type locality in Ohio ( Froeschner 1988a).

Aradids, as compared to other heteropterans, are generally encountered less frequently, being well-suited to their cryptic, subcorticulous habitat. Thus, it is unsurprising to add new aradids to the state faunal list. Indeed, based on adjacent state records, seven more species may yet be found in Illinois ( Froeschner 1988a). Yet, the decline of old growth forests over the last century ( Parker 1989) may have led to the extirpation of some species previously distributed in the state.

With the addition of Neuroctenus pseudonymus and Nannium pusio , six species of mezirine flat bugs are known from Illinois; the other four species are: Mezira granulata ( Say, 1831) ; Mezira lobata ( Say, 1831) ; Mezira sayi Kormilev, 1982 ; and Neuroctenus simplex ( Uhler, 1876) . The following key was constructed using Blatchley (1926), Torre-Bueno (1939), Kormilev (1982), and Davidová-Vilímová et al. (1996). An additional species of Mezirinae , Neuroctenus elongatus Osborn, 1903 , may yet be found in the state, given its presence in Indiana and Ohio ( Froeschner 1988a).

Figures

FIGURES 1 – 9. Dorsal habitus of nine Heteroptera newly reported for Illinois: (1) Neuroctenus pseudonymus, adult female; (2) Nannium pusio, adult female; (3) Metacanthus multispinus, adult male; (4) Anasa repetita, adult male; (5) Chelinidea vittiger, adult female; (6) Phymata fasciata fasciata, adult male; (7) Arhyssus nigristernum, adult male; (8) Aufeius impressicollis, adult female; and (9) Niesthrea louisianica, adult female. Scale bar = 1 mm.

FIGURES 10 – 14. Various collection sites of nine Heteroptera newly reported for Illinois: (10) near Brasher Cave, Pope County (Neuroctenus pseudonymus) (image © Matthew L. Niemiller); (11) Fogelpole Cave Nature Preserve, Monroe County (Metacanthus multispinus, Phymata fasciata fasciata); (12) Kidd Lake Marsh, Monroe County (Anasa repetita, Phymata fasciata fasciata); (13) White Rock Nature Preserve, Monroe County (Chelinidea vittiger); and (14) Fogelpole Cave Nature Preserve, Monroe County (Arhyssus nigristernum).

FIGURES 15 – 22. Current known distribution of eight Heteroptera newly reported for Illinois by state / province within the U. S. A. and Canada: (15) Neuroctenus pseudonymus; (16) Metacanthus multispinus; (17) Anasa repetita; (18) Chelinidea vittiger; (19) Phymata fasciata fasciata; (20) Arhyssus nigristernum; (21) Aufeius impressicollis; and (22) Niesthrea louisianica. Being known from only two states, the range of Nannium pusio is not depicted.