Melanocanthon bispinatus ( Robinson, 1941 )

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 : 21-25

5. Melanocanthon bispinatus ( Robinson, 1941)

Fig. 1 , 9–12 , 15 , 18 , 51–58

Canthon bispinatus Robinson 1941: 128 .

Melanocanthon bispinatus (Robinson) (new combination per Halffter 1958: 211).

Type material. Holotype male. National Museum of Natural History, Washington, DC. Not examined. See Comments below.

Type locality. Warren Grove, Burlington County, New Jersey.

Diagnosis. Head: Dorsum usually completely covered by small, round granules interspersed with very small punctures on shagreen background ( Fig. 51 ); usually lacking shiny microspots and any conspicuous larger, flat punctures along anterior portion of clypeus. Prothorax: Disk completely covered by elongate (“streaked”) granules and fine, but conspicuous, sharp punctures on shagreen background ( Fig. 52–53 ); granules becoming rounder laterally and posteriorly; shiny microspots usually absent. Elytra: Discal interstriae bearing widely scattered, unevenly distributed, small round granules on shagreen background ( Fig. 54 ); granules vary in size but tend to be larger, more conspicuous and more numerous on lateral interstriae. Pygidium : Evenly covered by variable sized, round granules. Venter: Generally without granulation except for occasional vestigial granules on sides of abdominal sternites 1–5 and across 6. Pteropleura and lateral portions of metasternite completely covered by very fine, dense striation; median portion of metasternite completely, evenly punctured. Legs: Metatarsus narrow, basitarsus longer than second tarsomere, apical tarsomere longer than combined lengths of tarsomeres 3–4 ( Fig. 55 ). Parameres: Ventral apical lobes of parameres expanded, triangular tabs with sharp, curved lateral angles ( Fig. 56–58 ); apical margins strongly curved outward medially, creating wide, oval gap (Fig, 57, arrow). General: Black. Length 6.0–10.0 mm. Geographic distribution: Eastern US from Mississippi to Michigan to Atlantic coast and northern Florida ( Fig. 15 , 18 ). Specimens examined: 1450.

Collection localities. CANADA — ONTARIO: Chatham-Kent Co. • Rondeau Provincial Park [Jun]; Lambton Co. • Pinery Provincial Park, 43°14′15″ N 81°52′31″, 43°18′ N 81°50′ W, 43°13′ N 81°54′ W, [May–Jul, Sep–Oct]. UNITED STATES — ALABAMA: Clay Co. • Springhill [Aug]; Dale Co. • Fort Rucker Military Reserve [Mar–May, Sep]; Geneva Co. • Geneva [Mar]; Mobile Co. • Chickasaw [Apr] • Mobile [May, Jul–Aug] • Dauphin Island [Jun]. CONNECTICUT: Hartford Co. • Suffield. DELAWARE: New Castle Co. • Wilmington. FLORIDA: Alachua Co. O’Leno State Park [May–Jun, Oct] • Austin Cary Memorial Forest [May] • 9.5 mi N Alachua [Aug] • 4 mi N High Springs [Mar] • 6 mi SW Gainesville [Apr] • 3.5 mi NE Gainesville [Sep]; Baker Co. • Glen St. Mary [Apr]; Bay Co. • 3 mi S Fountain [Jun] • Pine Log State Forest, 4.9 km SSE Ebro, 30.40464° N 85.88691° W [Oct] • Pine Log State Forest, 26.5 km NNW Panama City Beach, 30°24′17″ N 85°53′14″ W, 26 ft [Oct]; Calhoun Co. • Clarksville [Mar]; Citrus Co. • Withalacoochee State Forest, Citrus Wildlife Management Area [Jul]; Clay Co. • Bayard Conservation Area [May] • 9 mi NE Keystone Heights [Mar] • Ordway Preserve [Sep]; Columbia Co. • Lake City [Jun–Aug]; Dixie Co. • 3, 5 mi N Old Town [Apr]; Franklin Co. • St. Vincents Island [Jul] • Apalachicola National Forest, Wright Lake [Apr] • St. Vincents Island [Jul]; Gadsden Co. (no data) [Apr]; Gilchrist Co. • 5 mi NNW Newberry[Oct]; Hamilton Co. • 12 mi E Madison [Sep]; Hernando Co. • Withalacoochee State Forest, Chinsegut Conservation Center [Apr]; Lafayette Co. • Picket Lake [Mar]; Leon Co. • Bradfordville [May] • Tall Timbers Research Station [Apr] • Apalachicola National Forest, 30°19′34.34″ N 84°29′34.34″ W; Levy Co. • 4.5 km S Archer, 29°30′31″ N 82°33′53″ W, 26 m [Mar] • 5.5 mi SW Williston, 29°21.586′ N 82°31.089′ W [Mar]; Liberty Co. • Bristol [May] • 9 mi N Bristol [Apr] • Torreya State Park [Apr, Jul–Aug, Oct–Nov] • Apalachicola Bluffs and Ravines Preserve, 30°29′42.66″ N 84°58′42.46″ W, 183 ft [Mar, May, Jul]; Marion Co. • Ocala Silver Springs State Park, 29°11.84′ N 82°02.03′ W, 23 m [Feb–Mar]; Putnam Co. • 1 mi W Georges Lake [Mar] • Gold Head Branch State Park [Jul]; Suwannee Co. • Branford [Jun–Aug]; Walton Co. • Defuniak Springs [Mar] • 7.2 mi S Defuniak Springs [Jun] • Elgin Air Force Base [Jun] • County road 283, 0.3 mi S jct. US 90 [Jan]. GEORGIA: Bacon Co. • Alma (Nov); Baker Co. • Newton, Emory University Field Station [Mar]; Bulloch Co. • Statesboro [Jul]; Burke Co. • 0.2 km NW Girard, Yuchi Wildlife Management Area, 30°05′14″ N 81°48′17″ W, 218 ft [Apr], 33°05.104′ N 81°46.593′ W [Mar]; Camden Co. • Cumberland Island [Jul]; Charlton Co. • Folkston [Aug]• Suwannee Canal Recreation Area, Camp Cornelia [May] • Okefenokee Swamp [Aug]; Chatham Co. • Savannah [Jun] • 12 km NNW Richmond Hill, 32°02′41″ N 81°20′13″ W [May]; Clinch Co. (no data) [Apr]; Coffee Co. • 5 mi E Douglas [Jun]; Decatur Co. • Spring Creek [Jun–Jul]; Early Co. (no data) [Aug]; Emanuel Co. • 3.3 mi N Swainsboro, 32°40′37″ N 82°23′08″ W [Aug] • 9 mi SW Swainsboro [May] • 9.8 km WSW Swainsboro, 32.57174° N 82.43416° W • 4.5 km NE Norristown, Ohoopee Dunes Natural Area, 32.5285° N 82.4569° W [Jun–Jul]; Glynn Co. • Jekyll Island [Jun–Jul] • Brunswick [Jul]; Jefferson Co. • 15 mi SW Wadley [Mar]; Liberty Co. • Fort Stewart [Jun] • St. Catherines Island [Apr]; McIntosh Co., Blackbeard Island [Feb, Sep] • Sapelo Island, 31.40895° N 81.26634° W [May]; Richmond Co. • 12 km SW Augusta, 33°20′20″ N 89°09′25″ W [Oct] • 8 mi NE Wrens {in Jefferson Co.}; Screven Co. • Junction State Hwy 24 and US 301; Sumpter Co. • 1.9 mi W Americus [Mar]; Tattnall Co. • 3mi E Rte 147, along Ohoopee River [May–Jun] • 5 mi SW Reidsville [Sep–Nov]; Taylor Co. • 3 mi N Butler, 32.5998° N 84.2530° W [May–Jun]; Thomas Co. • Thomasville [Apr] • 10 km S Thomasville, 30°45.35′ N 83°59.93′ W, 7 m [Mar] • 4.5 mi S Thomasville [Jun] • Melrose Plantation [Apr] • Greenwood Plantation, 30°51′15″ N 84°01′01″ W [Sep–Oct]; Tift Co. • Coastal Plains Research Station [Jun] • Tifton [Jul]; Ware Co. • Waycross [Jul, Sep]; Wheeler Co. • Bells Ferry Road, Ocmulgee River [Apr, Aug] • 3.2 km NNE McRae, 32.09528° N 82.89099° W [May–Jun]. INDIANA: Jasper Co. • Jasper-Pulaski Fish and Wildlife Area [Jun]; Newton Co. • Beaver Lake Prairie Chicken Refuge, Kankakee Sands Preserve, 41°05′01″ N 87°24′22″ W [Jun–Jul], 41°04′56″ N 87°25′31″ W [Jun] • Conrad Savanna Nature Preserve [Jun]; Porter Co. • Indiana Dunes State Park, 41.6776 −87.0098, 190 m [May–Jun, Oct]. MARYLAND: Dorchester Co. • 2mi N Eldorado[May] • 3 mi W Hurlock [May] • 3 mi E Hurlock [May]; Wicomico Co. • Pemberton Historical Park, 38°20′53.58″ N 75°38′26.29″ W, 6 m [Apr] • Pemberton Historical Park, 38°20′49.79″ N 75°38′50.70″ W, 5 m [Jul]; Worcester Co. • Pokomoke State Forest, 38°11.406′ N 75°30.241′ W [Jun–Jul] • Pokomoke State Forest, 38°11′47.06″ N 75°30′15.35″ W, 12 m [Jun–Jul] • Pokomoke State Forest, 38.18845°N 75.49200°W, 10 m [Sep] • Pokomoke State Forest, 38.21900°N 75.52299°W, 10 m [Jul]. MICHIGAN: Antrim Co. • Grass River Natural Area [Jun–Jul]; Barry Co. • Barry Game Area [May]; Calhoun Co. • Ft. Custer; Clinton Co. • Rose Lake Conservation Area [Jul]; Leelanau Co. • Bingham [Jun]; Kalkaska Co. (no data) [Jun, Aug]; Livingston Co. • E. S. George Reserve, near Pinckney [Jul]; Newaygo Co. • 10 mi NE Newaygo [Aug]; Shiawassee Co. • Rose Lake Wildlife Experiment Station [Jun]. MISSISSIPPI: George Co. • Lucedale [Apr– Jun] • 4.5 mi NNW Lucedale [Jul]; Greene Co. • Leaf [Aug] • Avera [Apr]; Hancock Co. • Kiln; Harrison Co. • 3.5 mi SE Sancier [Apr–May, Jul]; Jackson Co. • Ocean Springs [Apr]; Lowndes Co. • 2.5 mi S Forreston, 33°18′02″ N 88°18′30″ W; Oktibbeha Co. (no data); Stone Co. • Wiggins [Jun] • 6.5 mi SE Wiggins • 6.5 mi ESE Perkinston [May]. NEW JERSEY: Atlantic Co. • 3.5 km SSE Weekstown, 39°33′49.7″ N 74°35′05.8″ W [May] • Cecil [May]; Bergen Co. • Wallington; Burlington Co. • Green Bank [Jun] • 7 mi W New Gretna [May] • Wharton State Forest [May] • Browns Mills [Sep] • Pemberton Township, Buffins Meadows [Jun]; Camden Co. • Atco [Jul]; Mercer Co. • Quaker Bridge (Sep]; Ocean Co. • Lakehurst [Jun] • East Plains [Aug–Sep] • West Plains [Jun–Sep] • Lacey Township, Cedar Bridge Fire Tower [Apr] • Whitesbog [May, Sep] • Bass River State Forest [Jul] • Warren Grove [Sep] • 1 mi W Warren Grove [Jun] • Lebanon State Park, Mt. Misery [May, Sep] • Ocean City [Jun]. NEW YORK: Suffolk Co. (no data) [Aug]; Nassau Co. • Long Beach [Jul]. NORTH CAROLINA: Bladen Co. Singletary Lake State Park, 34°35′00″ N 78°27′30″ W [May]; Brunswick Co. • Long Beach [May]; Cumberland Co. (no data); Currituck Co. • Knotts Island [May]; Dare Co. • Cape Hatteras, Buxton [Jun] • Nags Head; Hartnett Co. • Raven Rock State Park, 35.46207° N 78.91082° W; Hoke Co. • 1.5 mi SW McCain [Jun]; Moore Co. • Southern Pines [Apr, Sep]; New Hanover Co. • Carolina Beach State Park, 34.04688° N 77.91112° W [Jun]; Onslow Co. • Camp Lejuene [Jul]; Pender Co. • Holly Shelter Game Land [Apr, Sep]; Yancey Co. • Black Mountains. OHIO: Lucas Co. (no data) [Jun]. SOUTH CAROLINA: Aiken Co. • 1 mi S Windsor [Mar] • Aiken Gopher Tortoise Preserve, 10.7 km NE White Pond, 33°30′15″ N 81°24′22″ W, 259 ft [Apr], 33°29.350′ N 81° 26.311′ W • 10 km NE White Pond, Christmas Tree Road, 33°29′24″ N 81°23′ 23″ W, 327 ft [Apr] • 3 mi E Montmorenci [Mar]; Beaufort Co. • Beaufort [Aug]; Berkeley Co. • Jamestown [Jun]; Calhoun Co. • St. Matthews; Charleston Co. • McClellanville, Bull’s Island, 32°52′ N 79°37′ W [May, Aug]; Chesterfield Co. • McBee [Jul] • Cheraw State Park, 34°37′16″ N 79°56′40″ W, 34°38.010″ N 79°53.421″ W [Oct] • Carolina Sand Hills National Wildlife Refuge, 34.5855° N 80.2690° W, 34.5745° N 80.2232° W, 34.5626° N 80.2016° W, 34.5973° N 80.2400° W, 34.5476° N 80.2433° W [Mar, May]; Colleton Co. • Walterboro [Apr]; Darlington Co. • Pee Dee Recreation Area, 34.3070° N 79.7343° W [Jul]; Florence Co. • The Country Club of South Carolina [Apr]; Georgetown Co. • Baruch/Hobcaw, Belle Baruch Marine Field Station, 33°21′46″ N 79°13′33″ W [Apr–May] • Baruch/Hobcaw Barony, 33.3625° N 79.270° W [May] • Baruch/ Debidue Island, 33.3567° N 79.1526° W [May] • Georgetown [May]; Hampton Co. • Yemassee [Jul] • Scotia [Apr] • Hampton [Aug]; Horry Co. • Myrtle Beach [Apr, Jun]; Jasper Co. • Tillman [Aug]; Richland Co. • 6 mi E Columbia [Apr]; Pickens Co. • Clemson. TENNESSEE: Cumberland Co. • Black Mountain [May–Aug]; Stewart Co., Ft. Campbell Military Reservation, Site 6, 36.59527° N 87.71574° W [Sep]. VIRGINIA: City of Suffolk • 6 mi SSE Franklin, South Quay Natural Area, 36.92019 −76.00423 [Jul–Aug]; Cumberland Co. • 2–5.5 km SW Columbia [Jun–Sep]; Isle of Wight Co. • Antioch Pines Natural Area Preserve [Sep] • Blackwater Ecological Reserve, 36.822749 −76.855168 [Aug] • Zuni Pine Barrens, Blackwater Ecological Preserve, 36.82466 −76.85519 [Jul–Aug] • 7 km S Zuni; Sussex Co. • Chub Sandhills Natural Area Preserve, 36.874 −77.184. WEST VIRGINIA: Morgan Co. • 7 km E Paw Paw, 39.5224 −78.3641 [Jul].

Comments. The holotype cited above is assumed to be Robinson’s holotype male. Robinson’s original description of Canthon bispinatus was based on 46 specimens. Robinson retained the holotype, allotype and an unspecified number of paratypes in his own collection (now at the National Museum of Natural History) and distributed remaining paratypes among the collections of the Academy of Natural Sciences of Philadelphia, the United States National Museum (National Museum of Natural History), the American Museum of Natural History, and the private collection of R. C. Casselberry.

Melanocanthon bispinatus is a wide-ranging species and common in all collections examined for this study. Mario Cupello (pers comm) likened its distribution to that of Ateuchus lecontei (Harold) . As far as I know, M. bispinatus and M. nigricornis are allopatric. I have no reliable records placing them in the same state, although I harbor no serious doubt that they will ultimately be discovered in close proximity in the zone of potential sympatry depicted in Figure 19 . There is no potential barrier I can imagine that would prevent encounters in, for example, Illinois, Indiana and Mississippi. Especially in that zone, occasional specimens of M. bispinatus from Michigan and northern Indiana can express a weakened dorsal sculpturing very similar to that of M. nigricornis , especially on the head where granules can be almost effaced.

The distribution of Melanocanthon bispinatus depicted in Figure 15 is presumptuous in that it includes the entire Ohio River Valley, from western Pennsylvania to the Mississippi River. In fact, I have not seen specimens nor reliable reports of this species from at least 90% of this vast area, including all, or virtually all, of the states of Indiana, Ohio, Kentucky, Pennsylvania, and West Virginia (see Fig. 18 ). I think it reasonable to predict that it is indeed found there, even if only in widely scattered patches of suitable habitat. Alternatively, the populations clustered in Michigan and adjacent sites in far northern Indiana and Ohio, and in southeastern Ontario, might well be regarded as a widely disjunct Great Lakes enclave of this species. The latter alternative (absence from the Ohio River valley) begs the question of why it has not populated that area, an explanation for which I presently have no reasonable conjecture.

This species occurs sympatrically with M. punctaticollis in north central Florida and with M. vulturnus in northern Florida and adjacent southern Georgia and South Carolina ( Fig. 15 ), where it (especially females) can be difficult to separate. In general, however, the pronotal granulation of M. vulturnus is coarser and denser than that of M. bispinatus and often exhibits a metallic, greenish color never seen in this species. The parameres, however, are very distinctive ( Fig 56–58 ) and will readily separate M. bispinatus from both of its sympatric congeners.

Label data indicate that this very common, widespread species is attracted to a wide variety of food types, including human, pig, coyote, and cattle dung, rotting fruit, fruit mixtures (such as banana, beer, sugar mashup), fungi, as well as an isolated record of rolling a dead melolonthine beetle ( Scarabaeidae ). Harpootlian (1995, 2001) reported M. bispinatus as common in South Carolina sand hills and coastal plains habitats, on dead carabid and cicindelid beetles and fungi, as well as rolling deer and rabbit pellets. Robinson (1941) reported M. bispinatus on old, partly dried toadstools in New Jersey pine barrens. Nemes and Price (2015), Price et al. (2012), and Price and Ratcliffe (2023) have reported M. bispinatus to be a common eastern Maryland species in coastal habitats where it exploits dung, dry fungi, carrion and rotting fruit. Löding’s (1945) reference to M. nigricornis as common on fungi in Alabama probably referred to M. bispinatus . Young (2021) reported M. bispinatus to be the overwhelmingly dominant dung beetle in a long leaf pine habitat community in southwest Georgia (Baker Co.); it could be, however, that a portion of specimens sampled for the study were M. vulturnus , which was not recognized at the time but is now known from adjacent counties. Hinson (2011) found M. bispinatus to be among the scarcer species in scarabeoid communities sampled with flight-intercept traps in various habitats in South Carolina.

I have examined one specimen of M. bispinatus labeled Palm Beach Co., Florida, far to the south of its known range in the northern part of the state. I regard this record as doubtful pending confirmation. I have examined a Peck-collected voucher specimen from the Canadian Museum of Nature and confirmed that Peck and Howden’s (1985) reference to M. bispinatus on Big Pine Key (Monroe Co., Florida) refers to M. vulturnus (qv). Robinson (1948) listed M. bispinatus from Rhode Island and Pennsylvania, but I have seen no specimens from either state. Rounds and Floate’s (2012) reference to M. nigricornis in Missaukee County, Michigan, is probably referable to M. bispinatus , which I have seen from several nearby counties. I have no reliable records of M. nigricornis from Michigan.

Figures

Figure 15. Approximate distributions of species of Melanocanthon.

Figures 1–8. Generic features of Melanocanthon. 1) M. bispinatus (Robinson) habitus in vivo, New Hanover County, North Carolina. 2) M. nigricornis, habitus in vivo, Lake County, Illinois. 3) M. granulifer (Schmidt), right protibia-tarsus of male. 4) Same, frontal view middle portion clypeus (square encloses area magnified in Figure 5). 5) Same, spiniform clypeal process. 6) Same, shape of clypeal process modified by wear. 7) Same, lateral view of portion of head and prothorax. 8) Same, ventral view of head (arrow indicates labio-gular fimbria).

Figures 9–14. Generic features of Melanocanthon. 9) M. bispinatus (Robinson), oblique frontal view of pronotum highlighting microsetae. 10) Same, posterior view of pygidium. 11) Same, dorsal profile of habitus (image darkened to enhance silhouette). 12) Same, dorsal view of forebody. 13) Boreocanthon puncticollis (LeConte), dorsal profile of habitus (image darkened to enhance silhouette). 14) Canthon bispinus Harold, dorsal view of head.

Figures 16–19. Distributions of Melanocanthon species. 16) By-county distributions of M. vulturnus and M. punctaticollis. 17) Same, M. granulifer and M. nigricornis. 18) Same, M. bispinatus. 19) Central United States, rectangle demarcates area of potential sympatry between M. bispinatus and M. nigricornis (see text for explanation).

Figures 51–58. Melanocanthon bispinatus (Robinson).51) Dorsal view of head.52) Dorsal view of pronotum. 53) Dorsal view pronotal disk. 54) Dorsal view of left elytron. 55) Lateral view of metatarsus. 56) Oblique lateral view parameres. 57) Apical view of parameres (arrow indicates oval gap). 58) Lateral view parameres.