Boreocanthon probus (Germar, 1823)

Edmonds, W. D., 2022, Taxonomic review of the North American dung beetle genus Boreocanthon Halffter, 1958 (Coleoptera: Scarabaeidae: Scarabaeinae: Deltochilini), Insecta Mundi 2022 (952), pp. 1-65 : 40-45

Boreocanthon probus (Germar, 1823) restored generic combination

Fig. 72–82

Ateuchus probus Germar 1823: 98 .

Canthon probus (Germar) (new combination per LeConte 1863: 36).

Boreocanthon probus (Germar) (new combination per Halffter 1958: 210).

Canthon (Boreocanthon) probus (Germar) (new combination per Howden 1966: 727).

Boreocanthon integricollis (Schaeffer) , restored generic combination.

Coprobius minor Sturm 1843: 104 (new synonymy per Blanchard 1885: 165, as Canthon minor [Sturm]) nomen nudum.

Canthon abrasus LeConte 1859c: 11 (new synonymy per Horn 1870: 45).

Type material. 1) Ateuchus probus Germar : Syntype (sex undetermined), Museum für Naturkunde, Berlin. Examined by photograph, courtesy Fernando Vaz-de-Mello. 2) Coprobius minor Sturm : Unknown to me; 3) Canthon abrasus LeConte : Unknown to me.

Type localities. 1) Ateuchus probus Germar : North America (Kentucky) ; 2) Coprobius minor Sturm : America borealis; 3) Canthon abrasus LeConte : Georgia.

Diagnosis. Head: Anterior one-half clypeus finely roughened and sometimes highly reflective ( Fig. 79 ), forming bright band behind marginal teeth; remainder of surface dull, alutaceous, minutely punctured; head margin strongly sexdentate ( Fig. 74, 79 ), clypeal teeth strong, rounded apically, paraocular notch acute, anterior angle of paraocular area produced as strong tooth. Labio-gular fimbria gently bowed posteriorly, often followed medially by elongate field of coarse, setose punctures. Prothorax: Anterior angles ( Fig. 73 ) at most weakly upturned (more so in western populations). Surface ( Fig. 75 ) alutaceous with dispersed puncturing and compact microspotting, appearing smooth, weakly shiny to dull (especially in western populations), not depressed posteromedially. Hypomeral carina either absent or only weakly indicated. Pterothorax: Mesoventrite smooth, at most with few punctures. Metaventrite moderately shiny, with very small, evenly dispersed, widely spaced punctures. Elytra: Interstriae shagreened, with dense field of microspotting; 2 nd and 3 rd intervals not distinctly raised, 3 rd and 5 th lacking distinct tubercle on anterior margin. Striae superficial, edges sharp, especially basally; subhumeral (8 th) stria often carinulate ( Fig. 81 ; especially western populations); epipleural (9 th) stria effaced. Legs: Protibia gradually widened, inner margin not offset; apical spur sexually dimorphic, apex acute in female, bifurcate in male. Metafemur lacking conspicuous row of setae along anterior margin. Abdomen: Pygidium sculptured like elytra, sometimes noticeably more convex medially. Last visible (6 th) ventrite punctate along posterior margin, sometimes with small, median bump. Genital capsule: Compressed distal portion of parameres abbreviated, in form of equilateral triangle ( Fig. 76 ); ventral apical angles acute, capped by elongate knobs ( Fig. 77 ). General: Length: 4.0 – 5.5 mm. Dorsum dull black, pronotum sometimes with weak, green luster. Geographic distribution: Broad southerly region of United States from Atlantic coast to Rocky Mountains ( Fig. 82 , and see Comments). Ecogeographic environment ( Fig. 2 ): Temperate Grasslands, Savannas and Shrublands biome. Specimens examined: 719.

Collecting localities:

UNITED STATES — ALABAMA: Dale Co. ● Fort Rucker Military Reservation [Apr, Jun] ; Shelby Co. ● Longview . ARKANSAS: Little River Co. ● 11mi NE Texarkana. COLORADO: Morgan Co. ● 12 mi E Brush , 4280 ft ; Yuma Co. ● 5 mi W Joes. FLORIDA: Alachua Co. ● Gainesville Airport [Sep] ● 3.4 mi WNW mi W Archer [Aug] ● 0.75 mi W Archer [Jun] ; Bay Co., ● 26.5 km NNW Panama City Beach, Pine Log State Forest , 30°24 ʹ 17 ʺ N 85°53 ʹ 14 ʺ W [Oct] ; Charlotte Co. ● 27°01.224 ʹ N 81°57.573 ʹ W [Mar] ; Dade Co. Miami [Mar-Sep] ; Duval Co. ● Jacksonville ; Gilchrist Co. ● 5 mi W Newberg [Jun] ; Hernando Co. ● Brooksville [Jul] ; Highlands Co. ● Archbold Biological Station [Feb-Jun] ● Hammock State Park [Jun] ● Sebring [May] ; Hillsborough Co. ● Lutz [Feb-Apr] ● Hillsborough River State Park [Mar] ● Tampa [Apr] ; Indian River Co. ● Vero Beach [Nov]; Lafayette Co. ● Picket Lake [Mar] ; Lake Co. ● Forest Hills [Feb] ; Lee Co. ● 3.4 mi NW Koreshan State Park [Apr] ; Levy Co. ● 3.8 mi SW Archer [Mar] ; Liberty Co. ● Apalachicola Bluffs & Ravines Preserve, Alum Bluff [Jun] ; Marion Co. ● Citra [Apr] ; Martin Co. ● Jonathan Dickenson State Park [Dec] ; Miami-Dade Co. ● North Miami [Jul] ; Okaloosa Co., ● Elgin Air Force Base (Range 51) [Mar] ; Osceola Co. ● Kissimmee; Orange Co. ● Orlando [May] Palm Beach Co. ● Boca Raton [Aug] ; Pasco Co. ● 7 mi E Bayonet Point [Aug] ; Pinellas Co. ● Dunedin [Feb-Mar] ; Polk Co. ● Tiger Creek Preserve, 27°48 ʹ 42 ʺ N 81°29 ʹ 24 ʺ W [Jun] ; Putnam Co. ● Interlachen [May] ● 3 mi W Interlachen [Mar] ; St. Lucie Co. ● (no data) [Jan] ; Suwannee Co. ● Suwannee River [Aug] ● Branford [Aug] ; Taylor Co. ● Blue Springs Lake [Jun] ● Steinhatchee. (See also Woodruff 1973 for additional Florida records.) . GEORGIA: Baker Co. ● Newton, Ichauway Ecological Reserve [May] ; Burke Co. ● 10.2 km NW Girard, Yuchi Wildlife Management, 33°05 ʹ 13 ʺ N 81°48 ʹ 17 W ʺ [Mar-Apr]; Cobb Co. [Aug]; Decatur Co. ● Spring Creek [Apr, Jun-Aug]; Dougherty Co. ● Albany [Sep]; Emanuel Co. ● Ohoopee Dunes, 32°31 ʹ 51 ʺ N 82°27 ʹ 23 ʺ W ● George L. Smith State Park , 32.5503° N 82.1261° W [Jun] ● Swainsboro [Jul-Aug]; Glynn Co. ● Brunswick [Jun]; Haralson Co. ● Bremen [May]; Johnson Co. ● 1 mi E Kite [Aug]; Lamar Co. ● Milner [Aug, Nov]; Lowndes Co. ● Vidalia [Aug, Oct]; McIntosh Co. ● Sapelo Island , Nanny Goat Beach, 31.39065° -81.26533° [May]; Monroe Co. ● Bolingbroke [Aug]; Montgomery Co. ● Uvalda [Sep]; Richmond Co. ● Augusta [Mar] ● 12.5 km SW Augusta, 33°20 ʹ 20 ʺ 82°09 ʹ 25 ʺW ; Spalding Co. ● (no data) [Feb. Apr] ; Telfair Co. ● McRae [Jul] ; Tift Co. ● Tifton [Jul] ; Toombs Co. ● Vidalia [Aug] ; Walker Co. ● Head River [Aug] ; Ware Co. ● Waycross [Sep] ; Wheeler Co. ● Alligator Creek Wildlife Management Area , 21.8 km SSE Alamo, 31.96704 N 82.68711 W [Oct] . KANSAS: Phillips Co. (no data) ; Reno Co. ● Medora [Jun-Jul] ; Republic Co. (no data) ; Seward Co. (no data) [Jul] . LOUISIANA: Natchitoches Par. ● Vowells Mill . MARYLAND: Anne Arundel Co. ● Glen Burnie [Jul-Aug] ; Dorchester Co. ● 3 mi E Hurlock [May] ; Worcester Co. ● Nassawango Iron Furnace Site [Aug] . MISSISSIPPI: Forrest Co. ● Hattiesburg [Aug] ; Lincoln Co. ● Wesson [May] ; Oktibbeha Co. ● Starkville [Apr] . MISSOURI: Lewis Co., ● 7 mi S LaGrange, Wakonda State Park [Jun] . NEBRASKA: Dundy Co., Haigler [Jul] ; NEW JERSEY: Atlantic Co. ● Weymouth [Jun] ; Burlington Co. ● Masonville [Aug] ● Bridgeboro [Sep] ● Rancocas State Park [Jun-Jul] ● Woodland Township [Aug] ● Washington Township , Wharton State Forest [Aug] ● Bass River Township , East Plains [Jul] ● Warren Grove [Aug-Sep] ● Browns Mills [Aug] ; Camden Co. ● Clementon [May] ; Ocean Co. ● Manchester [Sep] ; ● Lakehurst [Sep] ● Union Township [Aug] . NEW MEXICO: Chavez Co. ● 38 mi E Roswell, Mescalero Sand Dunes [Jul] ; Curry Co. ● 19 mi N Clovis [Jun] ; DeBaca Co. ● 15 mi SE Fort Sumner [May] ; Eddy Co. ● 26 mi E Carlsbad [Jul] ; ● Waste Isolation Pilot Plant , 32°21.4 ʹ N 103°46.9 ʹ W [Jul] ● Artesia [Jun-Jul] ; Guadalupe Co. ● Santa Rosa [Jun] ; Lea Co. ● Crossroads [Apr]; Otero Co. ● White Sands [Jun] ; Quay Co. ● 10.5 mi NE Logan , 3850 ft [Aug] ; Roosevelt Co. ● Oasis State Park [Jul-Aug] ● 8 mi NE Portales, ENMU Natural History Reserve , [Jun-Sep] . NORTH CAROLINA: Moore Co. ● Southern Pines [JunAug] . OKLAHOMA: Carter Co. ● Ardmore [Jul] ; Logan Co. ● Hwy I-35 at Cimarron River [Apr] ; Payne Co. ● (no data) [May] ; Woods Co. ● (no data) [Jul] . SOUTH CAROLINA: Aiken Co. ● 5.3 mi E Montmorenci [Mar] ; Horry Co. ● Myrtle Beach [Jun] ; Kershaw Co. ● Cassatt [Nov] ; Pickens Co. ● Clemson [Apr-May] . TEXAS: Bexar Co. ● 3 mi S junction route 281 and Loop 1604 [Nov] ; Brazos Co. ● College Station [Apr] ; Comal Co. ● (no data) Crane Co. ● junction routes 1053 and 1233 (sandhills) [Jun] ; Dallas Co. ● Dallas ; Dimmit Co. ● 4 mi W Carrizo Springs [Sep] ; Erath Co. ● Stephenville [Aug] ; Frio Co. ● 4 mi W Dilley [Oct] ; ● 8 mi S Moore ; Gillespie Co. ● 7 mi S Doss [Apr] ; Hall Co. ● Memphis ; Harrison Co. ● Karnack [Jun] ; Howard Co. ● Big Spring [Aug] ; Kerr Co. ● Kerrville [Aug] ; Kinney Co. ● 20 mi E Brackettville [Apr, Oct] ; Lee Co. ● Fedor ; Tarrant Co. ● Arlington [Sep] ; Uvalde Co. ● Uvalde [Jun] ● 7 mi W Uvalde [Jun] ; Val Verde Co. ● Devils River at Dolan Falls [Jul] ; Ward Co. ● 1 mi E Monahans [Mar, Jul] ● Monahans Sandhills State Park [Aug] ; Willacy Co. ● Point Mansfield [May] (see Comments) ; Winkler Co. ● 10 mi NE Kermit, 31°56 ʹ 24.6 ʺ N 102°58 ʹ 41.3 ʺ W, 928 m [Jun] ● 16 mi NE Kermit , 31°57 ʹ 13 ʺ N 102°58 ʹ 15 ʺ W [Oct] .

Comments. Germar (1823) cited “America septentrionale (Kentucky)” as the type locality for his species, but I have seen no specimens from that state nor any bordering state. Dajoz’ (1994; cited by Lobo 2000) reference to Canthon probus in the Peloncillo Mountains of southeastern Arizona likely refers to B. puncticollis .

Blanchard (1885) synonymized B. probus and Coprobius minor Sturm (as Canthon minor ) without indicating the basis for his action or any reference to a description. The synonymy was noted by Woodruff (1973), Harpootlian (2001) and Ratcliffe and Paulsen (2008). Since Sturm’s name was published without description, it is a nomen nudum. Horn (1870) synonymized Canthon probus and C. abrasus LeConte , and noted “I have no hesitation in uniting the species of LeConte to that of Germar, and although some slight differences exist between the description and LeConte’s unique, it must be remembered that both species have been described from single specimens.” I do not know if Horn’s statement “single specimens” is accurate. Lacking any information to the contrary, however, I accept Horn’s opinion taking into account that, in the context of this study, the type locality of C. abrasus , Georgia, is home to only two species of Boreocanthon : B. depressipennis and B. probus .

A somewhat reliable identification flag for B. probus is an strongly sexdentate head with the clypeal teeth usually followed by a band of shiny integument ( Fig. 79 ). This glossy anterior portion of the clypeus contrasts markedly with the dull, shagreened expanse of the remaining head surface and marks specimens from throughout its range. Populations in eastern New Mexico and adjacent western Texas east of the Pecos River can closely resemble B. halffteri (q.v.), a similarity supporting the idea that it derives from B. probus (see below). Southwestern populations also tend to be darker and less lustrous than eastern populations and can lack the shiny clypeal band altogether; moreover, pronotal punctures tend to be larger, more conspicuous, anterior angles more prone to be upturned, as well as higher frequency finely carinate 8 th elytral stria. It is intuitively tempting to recognize eastern and western populations of B. probus as separate species, and perhaps a future, more rigorous analysis will support such action. For the present, however, I have no basis for confidently doing so and accept the notion that observed variability is more clinal than punctuated. Populations of B. probus from the eastern limit of its distribution also show considerable variation. I have seen numerous specimens from Rancocas State Park in southern New Jersey that are variable in ways similar to western populations; the dorsal surface from dull to lustrous and only 20–25% bear a shiny anterior band across the clypeus.

Figure 82 does not reflect several specimen records for B. probus in the far southern part of Texas, most notably Willacy County. Its presence there, while tenable, needs confirmation. It can be easily confused with B. integricollis , which is more common in that area. Likewise needing confirmation is its presence in Otero County, New Mexico (marked with a question mark in Fig. 82 ); I have seen a single specimen labeled White Sands.

Boreocanthon probus is very closely related to B. halffteri (q.v.), the latter so far known only from the Rio Grande basin in central New Mexico and very far west Texas. Specimens I have seen from Winkler and Ward Counties (Monahans sand dune system), as well as dunes in Crane Co. (Texas) and southeastern NM — that is, west Texas sand dune habitat roughly east of the Pecos River — I have assigned to B. probus . These populations are somewhat problematic taxonomically but very interesting biogeographically as they represent (as I currently interpret the situation) western variants of B. probus of an ilk that could have given rise to B. halffteri . Boreocanthon halffteri appears to be restricted to the red sand dune habitats characteristic of the Rio Grande drainage of New Mexico from north of Albuquerque to the Samalayuca dunes just south of Cd. Juarez. The probus - halffteri nexus would doubtless be a good subject for further study as it begs a number of questions very amenable to molecular and spatial analyses that are beyond the scope of this study, such as, is this area a possible hybridization zone.

Ecological notes on B. probus are scattered and brief. Staines (1984), cited by Nemes and Price (2015), listed food sources for B. probus as cow, rabbit and deer droppings. Miller (1954) collected numerous B. probus in Georgia, of which 90% were nocturnal. Woodruff (1973) reported that it is active year-round and prefers sandy, wooded habitats. Brown’s (1927) mention of B. lecontei as common on rabbit droppings in very sandy areas probably refers to B. probus . Halffter and Matthews (1966) reported B. probus as one of several dung beetle species inhabiting “… open forests of Eastern [ U.S.] lowlands …” that “… [cannot] be considered to be a forest form … because of the nature of the woods they inhabit—generally open, with much insolation of the substrate—and because they are also found outside the forests.” Indeed, B. probus is variable ecologically, inhabiting open forests in the eastern U.S. as well as open habitats west of the Mississippi River, including arid parts of western Texas. The common ecological denominator across these areas seems to be only that the substrate be sandy.

Figures

Figure 82. Approximate distributions of Boreocanthon probus (Germar) and B. halffteri, new species. Inset depicts recorded collection sites for B. halffteri (solid red circles) and in western Texas for B. probus (solid lavender triangles;? = doubtful site for B. probus, q.v).

Figures 72–81. Boreocanthon probus (Germar). 72) Habitus, dorsal view. 73) Habitus, oblique anterolateral view. 74) Dorsal view forebody. 75) Area of pronotal surface. 76) Lateral view of genital capsule. 77) Apical view of parameres. 78) Dorsal view of forebody with adherent white sand grains. 79) Dorsal view of head. 80) Apical view of female abdomen (pyg = pygidium; arrow [a] indicates apex of paraproct; arrow [b] indicates flange of pygidial margin; asterisk marks breach in intersegmental membrane, not a natural orifice).81) Dorsolateral view of elytron (arrow marks carinulate 8th stria).

Figures 1–2. 1) Approximate corporate distribution of the genus Boreocanthon. 2) Generalized depiction of vegetation biomes of the United States (Biome key in box; See Materials and Methods for explanation).