Boreocanthon lecontei ( Harold, 1868 )

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 : 26-28

Boreocanthon lecontei ( Harold, 1868) , restored generic combination

Fig. 29–35 , 100

Canthon lecontei Harold 1868: 68 .

Boreocanthon lecontei (Harold) (new combination per Halffter 1958: 209).

Canthon (Boreocanthon) lecontei Harold (new combination per Howden 1966: 727).

Boreocanthon lecontei (Harold) , restored generic combination.

Type material. Syntype (sex undetermined). Museum für Naturkunde, Berlin. Examined by photograph courtesy of Fernando Vaz-de-Mello.

Type locality. Texas.

Diagnosis. Head: Anterior portion roughened, punctatorugose, posterior portion granulorugose, shagreen reduced to isolated patches ( Fig. 32 ). Clypeus quadridentate, teeth subacute, separated by narrow, V-shaped emargination ( Fig. 29, 32 ). Paraocular notch reduced, setting off small, rounded angle of paraocular area. Labiogular fimbria broadly V-shaped medially, apex extending almost half length of gula. Prothorax: Pronotum ( Fig. 31 ) evenly, densely, finely granulate; granules irregular, confluent, obliterating most of shagreen background, which survives in small, isolated patches. Anterior pronotal angles only very weakly upturned, posteromedian angle not depressed; circumnotal ridge entire, not serrate posteriorly. Hypomeral carina present. Pterothorax: Mesoventrite smooth; metaventrite finely, sparsely punctate on strong shagreen background. Elytra: Interstriae ( Fig. 33 ) finely alutaceous, microspotting conspicuous; 2 nd and 3 rd slightly, if at all raised anteriorly. Striae ( Fig. 33 ) fine, superficial, lateral margins weakly defined; subhumeral (8 th) stria carinulate, sometimes only weakly so; epipleural (9 th) stria usually obsolete, sometimes persisting as vague fragments. Legs: Inner protibial margin not offset, almost straight; spur sexually dimorphic, apex acute in female, bifurcate in male. Hind femur lacking anterior row of conspicuous setae. Abdomen: Pygidium ( Fig. 34 ) densely alutaceous, slightly more convex apically. Last (6 th) ventrite with sparse puncturing on weak shagreen background; remaining ventrites (1-6) smooth. Genital capsule: Compressed distal portion of parameres ( Fig. 35b ) shortened, triangular, ventral apical angles in form of elongated knobs ( Fig. 35a ). General: Black, sometimes with dark blue undertone. Length: 3.5 – 6.0 mm. Geographic distribution ( Fig. 100 ). South Texas and adjacent northeastern Mexico. Ecogeographic environment ( Fig. 2 ): Desert and Xeric Shrublands, and Tropical and Subtropical Grasslands, Savannas and Shrublands biomes (Western Gulf coastal grasslands, Tamaulipan mezquital and Tamaulipan matorral ecoregions). Specimens examined: 241.

Collection localities.

MEXICO — NUEVO LEON: Mpio. Linares ● 8 mi S Linares [ Aug ] ; Mpio. Sabinas Hidalgo ● Sabinas Hidalgo [Jun] . SAN LUIS POTOSÍ: Mpio. Ciudad Valles ● 31 mi N Cd. Valles, 1000 ft [ Aug ] . TAMAULIPAS: Mpio. Abasolo ● Abasolo [May] ; Mpio. El Mante ● Cd Mante [Jul] ; Mpio. Valle Hermoso ● 14 mi SW Santa Teresa [ Aug ] .

UNITED STATES — TEXAS: Atacosa Co. ● Pleasanton [Jun]; Bexar Co. ● San Antonio, Salado Creek (Jun-Jul]; Cameron Co. ● Brownsville [Apr]; ● Port Isabel [Jun] ● 1 mi N Laguna Vista [Oct] ● 8.9 km N Los Fresnos, 26.15100° -97.46923° [Sep] ● Sabal Palm Grove Sanctuary [Oct]; ● 9 mi E Rio Hondo [Jun] ● 11 km NE Rio Hondo, 26.31193° -97.51292° [Sep] ● 14 mi E Rio Hondo ● Laguna Atascosa National Wildlife Refuge, 23.23291°N 97.35214°W [Sep-Nov]; Comal Co. ● (no data); Duval Co. ● 5 mi S Realitos [Mar]; ● 2.2 mi W Freer [Sep]; Hidalgo Co. ● Bentsen Rio Grande Valley State Park [Jun] ● Las Palomas Wildlife Management Area, Penitas Unit [Apr] ● Hidalgo [Aug] ● 7 mi SE Alamo [May]; Kerr Co. ● Kerrville [Aug]; Kleberg Co. ● Kings Ranch at Kingsville [Oct]; Live Oak Co. ● 15 mi SW George West [Oct]; McMullen Co. ● 6 mi SW Whitsett [Sep]; ● Calliham [Nov]; Travis Co. ● Austin; Uvalde Co. ● Uvalde [Jun-Jul] ● 7 mi W Uvalde ● Garner State Park [Jun] ● Concan [May]; Val Verde Co. ● Del Rio [Nov]; Starr Co. ● 14 mi E El Sauz [Oct]; Webb Co. ● Laredo [Apr] ● 15 mi N Laredo [May]; Williamson Co. ● Taylor [Aug].

Comments. This species is easily recognizable by its pronotal sculpturing, which consists of a unique, double granulation. The primary (larger) granulation is very fine and densely coalescent, producing an even, rather finely granulorugose surface; the secondary (much smaller) granulation, responsible for the shagreen background characteristic of the genus, appears in small, isolated patches. Similar sculpturing also presents on the posterior portion of the head and pygidium, but does not extend to the elytra. I consider B. lecontei a taxonomic isolate with no close affinity to any other known congener. Its distribution ( Fig. 100 ) completely overlaps that of B. integricollis but extends somewhat farther to the north.

Lindquist (1935) studied the life history of B. lecontei in Uvalde, Texas, where he found it to be attracted to carrion in addition to excrement. Blume (1970) recorded this species from the cattle dung community in Kerr County, Texas. Besides carrion and cattle dung, my records show it to be attracted also to swine and equine feces.

Figures

Figures 29–35. Boreocanthon lecontei (Harold). 29) Habitus, dorsal view. 30) Habitus, anterolateral view. 31) Partial dorsal view of head and pronotum. 32) Dorsal view of head. 33) Dorsal view of left elytron. 34) Posterior view of pygidium. 35) Male genitalia. a) Apical view of parameres. b) Lateral view of genital capsule.

Figures 100–101. Boreocanthon distribution.100) Approximate distributions ofBoreocanthon simplex (LeConte), B. lecontei (Harold) and B. coahuilensis (Howden).101) Solid red diamonds mark California collection sites for B. simplex with red elytral humeri in one or more specimens; shaded area marks general limits of the Central Valley.

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).