Melanocanthon nigricornis ( Say, 1823 )

Edmonds, W. D., 2023, Taxonomic review of the North American dung beetle genus Melanocanthon Halffter, 1958 (Coleoptera: Scarabaeidae: Scarabaeinae: Deltochilini), Insecta Mundi 2023 (14), pp. 1-28 : 13-17

publication ID	https://doi.org/ 10.5281/zenodo.10270977
publication LSID	lsid:zoobank.org:pub:FA7D5D5E-CEB8-48ED-A442-74C315FCF5E4
persistent identifier	https://treatment.plazi.org/id/EA615F14-FFA9-FFCF-FF1C-FBD6FB1C4CA8
treatment provided by	Felipe
scientific name	Melanocanthon nigricornis ( Say, 1823 )
status

Treatment

3. Melanocanthon nigricornis ( Say, 1823) View in CoL

Fig. 2 View Figures 1–8 , 15 View Figure 15 , 17 View Figures 16–19 , 34–42 View Figures 34–42

Ateuchus nigricornis Say 1823: 207 View in CoL .

Canthon nigricornis (Say) View in CoL (new combination per Melsheimer 1853: 53).

Melanocanthon nigricornis (Say) View in CoL (new combination per Halffter 1958: 209).

Type material. Unknown to me.

Type locality. Cape Gerardeau [now Cape Girardeau, Missouri]; New Jersey (See Comments below).

Diagnosis. Head: Dorsum lacking distinct granulation except for few weak granules near eyes and on paraocular areas, otherwise distinctly, evenly covered by mixture of very small punctures and shiny microspots on shagreen background ( Fig. 34 View Figures 34–42 ). Anterior portion of clypeus weakly roughened, bearing few somewhat larger punctures ( Fig. 34 View Figures 34–42 ); lacking any conspicuously large, flat punctures. Pronotum: Evenly covered by mélange of attenuated, very fine, elongate shiny granules and very fine, but conspicuous puncturing (25×) on shagreened background ( Fig. 35 View Figures 34–42 ); granules weaker, shinier, less well defined on disk, usually more distinct and less shiny laterally and posteriorly. Elytra: Interstriae weakly granulate on shagreen background with interspersed, very fine punctures ( Fig. 36 View Figures 34–42 ); granules small, round, varying in size, and scattered, seldom forming loose rows, weakest and least numerous on middle portions of discal interstriae (3–6). Pygidium : Evenly granulate. Venter: Dorsal granulation not extending to venter; pteropleura ( Fig. 38 View Figures 34–42 ) covered by dense microstriation, abdominal sternites ( Fig. 37 View Figures 34–42 ) smooth, metaventrite evenly, densely punctate. Legs: Metatarsus ( Fig. 39 View Figures 34–42 ) wider; lengths of tarsomeres 1–4 about equal to width at apex; length of apical tarsomere (excluding claws) about equal to combined lengths of tarsomeres 3–4. Parameres: Ventral apical lobes ( Fig. 41 View Figures 34–42 ) flattened, oval tabs; apical margins usually somewhat curved outwardly at middle, creating narrow, oval gap. General: Black. Length 4.0– 8.5 mm. Geographic distribution: Central United States ( Fig. 15 View Figure 15 , 17 View Figures 16–19 ). Specimens examined: 938.

Collection localities. MEXICO — NUEVO LEON: Mpio. Monterrey • Monterrey [Jun].

UNITED STATES — ARKANSAS: Drew County • Hunger Run West ( County Road 12), 33°41.75′ N 91°53.52′ W [Aug] GoogleMaps ; Izard Co. • Devil’s Knob , 36°00.19′ N 92°03.05′ W [Apr] GoogleMaps ; Lawrence Co. • Imboden [Aug] ;

Nevada Co. • White Oak Lake State Park [Apr] • 2.4 mi SSE Bluff City [Mar]; Saline Co. • Middle Fork Barrens Natural Area, 34°38′16″ N 92°50′31″ W [Sep]. COLORADO: Morgan Co. • 3 mi N Orchard [Jun]. ILLINOIS: Lake Co. • Zion, Illinois Beach State Park [Jul]; Mason Co. • Sand Ridge State Forest, 5 mi W Manito [Jul]. IOWA: Muscatine Co. • Big Sand Mound Prairie Preserve, 41.341015 −91.086545 [Jun]. KANSAS: Geary Co. • Fort Riley, Macomb Hill [May]; Pottawatomie Co. • 5 mi S Olsburg, Little Gobi Desert; Reno Co. • Sand Dunes State Park, 38°07′00″ W 97°50′40″ W [Oct]. LOUISIANA: La Salle Par. • Olla [Mar]; Natchitoches Par. • Kisatchie National Forest, Red Dirt Wildlife Management Area [Apr] • Kisatchie National Forest, Lotus Campground [Sep–Oct] • Vowells Mill. MINNESOTA: Anoka Co. [Jun–Aug] • Cedar Creek Natural History Area; Isanti Co. [Jun–Aug] • Cedar Creek Natural History Area; Sherburne Co. • Elk River [Jun] • Sand Dune State Forest [Jun]; Wabasha Co. • McCarthy Lake, Weaver Dunes, 44°16′ 26.85″ N 91°56′ 55.08″ W [Jul]. MISSOURI: Barry Co. • Roaring River State Park [Aug]; Boone Co. • Columbia [Jul]; Cole Co. • 4 mi W Jefferson City [Aug]; Stone Co. (no data) [May]. NEBRASKA: Arthur Co. (no data) [Jul]; Boyd Co. (no data); Cherry Co. • 25 mi N Valentine [Sep]; Custer Co. • Anselmo [Jun] • Milburn [Aug]; Dawes Co. • Whitney [Sep] • Pine Ridge [Jul]; Dodge Co. • Dead Timber State Recreation Area, 3.5 mi N Scribner, 41.7236° −96.6971° [Apr]; Dundy Co. • Max [Jul] • 2 mi E Benkelman [Jum]; Hall Co. • Mormon Island State Recreation Area [Aug]; Hitchcock Co. (non data) [Apr]; Hooker Co. (no data [Aug]; Keith Co. • 7 mi E Cedar Point Biological Station, 41.18° −101.52° [Jul] • Cedar Point Biological Station [Jul]; Lincoln Co. • 14 mi NW North Platte; Madison Co. • Meadow Grove [Jun]; McPherson Co. • Tyron [Jun] • Sandhills Agricultural Laboratory [Jul]; Merrick Co. • 1.5 mi E Silver Creek [Aug]; Thomas Co. • Nebraska National Forest, Whitetail Camp, Dismal River, 41.792° −100.267°, 820 m [Jun] • Nebraska National Forest, 1.3 km SSW Bessey Bee Campground, 41.88937° N 100.30676° W [Sep] • Halsey, 41.9033° -100.2686° [Jul–Aug] • 2.5 mi W Halsey, Nebraska National Forest [Jun] • Thedford [Aug] • 10.5 mi S Thedford. OKLAHOMA: Alfalfa Co. • Salt Plains National Wildlife Reserve [Apr]; Choctaw Co. • Schooler Lake [Aug]; Comanche Co. • Wichita Mountains Wildlife Refuge [Apr, Jul]; Latimer Co. (no data) [Apr–Sep]; Le Flore Co. • Ouachita National Forest [Jul]; Woods Co. • 14mi N, 7 mi W Alva [Nov]. SOUTH DAKOTA: Bennett Co. • 10 mi E Martin, La Creek National Wildlife Refuge [May]. TEXAS: Anderson Co. • 2 mi W Blackfoot, Engeling Wildlife Area [May, Aug–Sep] • 7 mi E Palestine 31°45′N 95°29′ W [Jun] • 14 mi E Palestine, 31°45′N 95°23′ W [Jun]; Angelina Co. • Angelina National Forest, ~ 3 mi NE Rockland, 31°03′19″ N 94°22′06″ W; Aransas Co. • 7 mi N Fulton [Mar]; Atascosa Co. • 8 mi NW Poteet [Apr–May] • 8 mi E Rossville; Bastrop Co. • 6mi N Smithville, Stengl Biological Station, 30°05′10.2″ N 97°09′44.3″ W [Jun] • 7.3 mi S Rosanky [Apr] • ~ 2.5 mi E jct. Hwy 95 on Hwy 21 [Mar] • Lake Bastrop [Apr] • Bastrop [Apr] • Bastrop State Park [Apr–Jul] • Bastrop [Mar–Apr] • 8.6 km N Bastrop, Camp Swift National Guard, 30.300° N 97.294° W [Jun–Sep] • Sayersville [Jul]; Brazos Co. 12 mi NE Bryan [Jul] • College Station, Lick Creek Park [Jan–Feb, Jul, Sep–Oct] • 10 mi W Kurten [Jul]; Burleson Co. • 30°30.713′ N 96°47.911′ W, 2.5 mi N jct. Hwy 21 on FM 908; Callahan Co. • Baird [Apr]; Colorado Co. • Rock Island [Jun]; Erath Co. • Stephenville [Apr]; Freestone Co. Buffalo [Mar] • 5 mi E Donie, Old Spring Seat Church [May]; Hardin Co. • Roy E. Larson Sandyland Sanctuary, 5 mi W Silsbee [Mar] • 1 mi W Silsbee [Sep]; Houston Co. • 12 mi NNW Ratcliff, 31°33′ N 95°09′ [Jun] • 11 mi WNW Crockett, 31°23′ N 95°36′ W [May] • 4 mi NNE Kennard, 31°24′ N 95°09′ W [Jun] • 2 mi SW Kennard, 31°20′ N 95°13′ W [May] • 17 mi NE Crockett, 31°30′ N 95°16′ W [May] • 19 mi NE Crockett, 31°29′ N 95°13′ W [May]; Lamar Co. • 3.5 mi S Powderly, Camp Maxey National Guard, 33.801° N 95.554° W; Lee Co. • Fedor [May]; Leon Co. • Marquez [May] • 9 mi ENE Buffalo, 31°32′ N 95°55′ W [May] • 5 mi SSW Buffalo, 31°23′ N 95°05′ W [Sep] • 1 mi SSE Jewett, 31°20′ N 96°07′ W [Apr–May] • 5 mi N Jewett, 31°26′ N 96°08′ W [Apr–May] • 4 mi NNW Normangee, 31°04′ N 96°09′ W [Sep–Oct] • 7 mi SW Centerville, 31°11′ N 96° 04′ W [Apr] • 5 mi E Centerville, 31°15′ N 96°52′ W [Sep] • 3 mi N Centerville, 31°16′ N 96°57′ W [Sep] • 4 mi S Centerville, 31°15′ N 96°52′ W [Sep] • 2 mi NW Centerville, 31°16′ N 96°52′ W [Sep] • 7 mi SSW Centerville, 31°16′ N 96°11′ W [Apr] • 8 mi NNE Centerville, 31°10′ N 96°00′ W [Sep] • 9mi SSE Oakwood 31°26′ N 95°48′ W [May] • 5 mi N Flynn [May] • 4 mi WNW Leona, 31°09′ N 96°02′ W [Sep]; Limestone Co. • 7 mi E Kosse [May]; Madison Co. • 4 mi W North Zulch [Apr] • 9 mi ESE Madisonville, 30°54′ N 95°46′ W [Sep–Oct]; Milam Co. • 4 mi N Gause, Sugarloaf Mountain, 300 ft [Apr, Aug–Oct]; Montgomery Co. • Conroe [Apr] • Willis [Apr]; Refugio Co. • Austwell; San Patricio Co. • 8 mi NE Sinton, Welder Wildlife Refuge [May–Jun]; Trinity Co. • Davy Crockett National Forest, 31°01′ N 94°00′ W [Jun]; Tyler Co. • Kirby State Forest, 30°34′30″ N 94°25′03″ [Apr, Jun]; Victoria Co. • Victoria [Apr]; Walker Co. • 12 mi SSW Huntsville, Lake Stubblefield [Jul] • Huntsville, Sam Houston State University Center for Biological Field Studies [Jun] • 11 mi NNW Huntsville [Apr]; Wood Co. • 18 mi N Hawkins, 32°48′55″ N 95°10′00″ W [May].. WISCONSIN: Adams Co. (no data) [Jun]; Iowa Co. • 1 mi NW Arena [Jul]; Monroe Co. • 2.4 mi SW Mather {Juneau Co.} [Jun] • 2.8 mi S Warrens [Jun]; Oconto Co. (no data); Polk Co. • Trade River [Jun] • Fort McCoy, Alderwood Dunes [May]; Sauk Co. • Spring Green Preserve State Natural Area, 43.2031° N 90.0568°W [Jun].

Comments. To my knowledge, type specimens of Melanocanthon nigricornis are missing. Much of Say’s collection was lost or destroyed many years ago ( Weiss and Ziegler 1931; Mawdsley 1993). No specimens attributable to A. nigricornis are present in the surviving collection of Say material at the Museum of Comparative Zoology at Harvard University, nor in the Melsheimer, Harris or LeConte collections there (Crystal Maier, pers. comm.). Nor are specimens attributable to Say known in the collections of his foreign correspondents (Mario Cupello, Fernando Vaz-de-Mello, Stéphane Boucher, pers. comm.). About M. nigricornis Say (1823: 207) wrote, “I have observed this species near Cape Gerardeau [sic], and in the intermediate country between that town and the Rocky Mountains; and as I formerly obtained two specimens in New Jersey, I think it probable that it inhabits a principal portion of our country; but it does not seem to be common any where [sic] …” It is obvious that, for his description of Ateuchus nigricornis, Say had at hand specimens representing two modern species, an unknown number of M. nigricornis and two of M. bispinatus , both of which conform equally well with his original description. Moreover, it is clear, given the very title of Say’s 1823 paper (“… coleopterous insects collected in the late expedition to the Rocky Mountains …” that specimens of M. nigricornis were the main basis of his description. Since New Jersey is home to only a single here-recognized species, M. bispinatus , I find it reasonable to assume, for present purposes, that Say’s New Jersey specimens, if extant, would today be assignable to Melanocanthon bispinatus (Robinson) , and that the remainder of his type series would remain M. nigricornis as here defined, with the type locality of Cape Girardeau, Missouri. For purposes of this review, the conditions favoring designation of a neotype for Ateuchus nigricornis Say as set forth in Article 75 of the International Code of Zoological Nomenclature (ICNZ 1999) are not satisfied as the name nigricornis , as used here, conforms with long-standing usage unrelated to any complex nomenclatorial problem.

The pronotal granulation of M. nigricornis is routinely rather fine and may be almost effaced on the disk so as to resemble the velvety texture of M. punctaticollis . Only rarely are the granules strongly raised on the central portion of the disk (Custer Co., Nebraska). The central portion of the dorsal surface of the head is smooth and distinctly punctate, only rarely with distinct granules (Bennett Co., South Dakota). There are scattered instances hinting of hybridization between M. nigricornis and M. bispinatus in Michigan. Occasional specimens of the latter species resemble the former in lacking well defined granules on the central portion of the head. Moreover, I have seen a single specimen from Nevada Co., Arkansas, with abnormal parameres reminiscent of M. bispinatus ( Fig. 42 View Figures 34–42 ).

Except for that portion occupying eastern Texas, the distribution of M. nigricornis is more-or-less congruent with the expansive western portion of the drainage system of the Mississippi River as well as that northern portion of the drainage embracing Illinois and Wisconsin. To what extent it might overlap with that of M. bispinatus is very much open to question. The depiction presented in Figure 15 View Figure 15 is based on data gathered for this study; it suggests a barrier of some sort, perhaps ecological. I strongly suspect that careful collecting, especially in the zone indicated in Figure 19 View Figures 16–19 , will reveal that the two species are, in fact narrowly sympatric in places, but I presently have no evidence that they are.

Blatchley’s (1910) reference to M. nigricornis from Starke Co., Indiana, is likely referable to M. bispinatus , as is that of Rounds and Floate (2012) for Missaukee Co., Michigan. The collection locality record above for Morgan Co., Colorado, while certainly reasonable, needs confirmation. Melanocanthon nigricornis is not recorded for Colorado by Krell (2010), but he points out records from bordering Nebraska. I have seen one specimen labeled Lucedale [George Co.], Mississippi; Paul Lago (pers. comm.) considers this record doubtful and in need of confirmation.

Vestal (1913) observed M. nigricornis , along with Canthon pilularius (L.) and Canthon vigilans LeConte in sandy, bunchgrass habitat along the Illinois River valley between Peoria and Meredosia. Fincher et al. (1986) reported it to be diurnal in wooded habitat Burleson Co., Texas; however, King (1914) found it attracted to electric lights. Williams and Kriska (2001) observed a group of a dozen individuals of M. nigricornis in Iowa County, Wisconsin, as they cut up, rolled away and buried pieces of “gill mushroom”, as well as direct feeding on a dead lizard and rolling carrion in neighboring Grant County. Freese et al. (2020) reported this species from deer and dog feces in various sandy and loess habitats in Iowa. Wagner et al. (2020) found M. nigricornis to be among the scarce species in a Nebraska Sandhills pasture ecosystem dominated mostly by native species of Onthophagus . I have label data recording attraction of M. nigricornis to cattle, pig, and human dung as well as to carrion (fish), fungi and rotting fruit. Whipple and Hoback (2012) reported that M. nigricornis was attracted to a wide variety of dung sources in food-choice trials utilizing excrement from native and exotic mammals.