Melanocanthon punctaticollis ( Schaeffer, 1915 )

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 : 9-10

1. Melanocanthon punctaticollis ( Schaeffer, 1915)

Fig. 15–16 , 20–26

Canthon nigricornis var. punctaticollis Schaeffer 1915: 50 .

Canthon punctaticollis Schaeffer (new status per Blatchley 1927: 61).

Melanocanthon punctaticollis (Schaeffer) (new combination per Halffter 1958: 211).

Type material. Syntype, male. National Museum of Natural History, Washington, D. C. Not examined.

Type locality. Florida.

Diagnosis. Head: Dorsum (25×) sharply punctured on shagreen background ( Fig. 20 ); granules and microspots either lacking or weak and perceptible only posteriorly. Clypeus weakly roughened, somewhat shinier anteriorly with transverse array of 10–15 large, shallow punctures ( Fig. 20–21 ). Pronotum: Evenly covered by distinct (25×) puncturing ( Fig. 22 ); granules and shiny spots usually absent, weak granulation sometimes present posteriorly. Elytra: Interstriae bearing widely and unevenly scattered, very small granules best observed in oblique view ( Fig. 25 ); shagreen very fine, obscure. Pygidium : Covered by weak, irregularly shaped granules on shagreen background ( Fig. 24 ), basal impressions weak, sometimes virtually absent. Venter: Generally smooth with some irregular wrinkling on sides of abdominal sternites; pteropleura and sides of metaventrite lacking any trace of granulation; central portion of metaventrite evenly, finely punctured. Parameres: Ventral apical lobes small, rounded tabs; apical margins usually only weakly curved outwardly at middle. General: Dull black, lacking any metallic undertones. Length 6.0–11.0 mm. Geographic distribution: Endemic to Florida peninsula ( Fig. 15–16 ). Specimens examined: 634.

Collection localities. UNITED STATES — FLORIDA: Alachua Co. • 3.4 mi WNW Archer, Ashton Biological Preserve [Mar – Aug] ; Clay Co. • Gold Head Branch State Park , 29.8475 −81.9617 [Feb, May] • Ordway Preserve [Sep] ; Collier Co. • Old Hwy 41 at Sun Century Rd [Oct – Nov] ; DeSoto Co. • Arcadia [May] ; Gilchrist Co. • 5 mi W Newberry ; Highlands Co. Lake June State Park 27°17′59″ N 81°25′28″ W [May – Jun] • Archbold Biological Station [Mar – Aug] ; Lake Co. • Grasshopper Lake, Ocala National Forest [Mar] • Lake Delaney , Ocala National Forest [Mar] ; Levy Co. • 8 mi E Bronson [Mar] • 3.8 mi SW Archer [May] • 2 mi W Archer [Mar, Aug] • 4 mi W Archer [Mar] • Cedar Key [Mar] ; Marion Co. • 3 mi E Eureka [Jun] • Ocala National Forest [Mar, May – Jun, Aug] • Juniper Springs [Apr] • Delancy [Aug] • Lake Marion Creek Estates [May] ; Okeechobee Co. • 22 mi N Okeechobee [Jan – Apr] ; Orange Co. • Wekiwa Springs State Park [Feb, Jun–Sep] • Orlando [Jul] • Central Florida University campus, 28°36′16″ N 81°11′38″ W [Feb, May – Sep] ; Osceola Co. • Walt Disney World [Jul]; Polk Co. • Catfish Creek State Park, 27.98457 −81.49606 [Jun] • Lake Marion Estates [Apr – Jun] ; Putnam Co. • 4 mi W Rodman, 0.8 mi E Deep Creek [Mar] • Welaka Research Station [Apr, Oct, Dec] • 1 mi W Georges Lake [Mar] • 3.2 mi NE Florahome [Jan] • Red Water Lake [Jun] • 3 mi S Melrose [Jun] • 3 mi E Melrose [Feb, Oct] • Interlachen [Apr] ; Seminole Co. • Geneva Wilderness Area, 28.704738 −81.122344 [Oct] • Econ River Wilderness Area [Mar – Apr] .

Comments. This species is endemic to the Florida peninsula, where it is sympatric with both M. bispinatus and M. vulturnus . Woodruff (1973) captured numerous specimens using malt traps in central Florida turkey oak ( Quercus laevis Walter ) scrub habitat. I have label records of capture from cattle, human and swine feces, fungi, yeast trap as well as from dead lubber grasshoppers ( Orthoptera : Romaleidae ) and in the soil pushup at the entrance to a gopher nest burrow ( Geomys ). Sandor Kelly (pers. comm.) routinely observes M. punctaticollis using various fleshy fungi, both fresh and desiccated, in Central Florida uplands, where it can occur along with M. vulturnus . Feeding aggregations are lively as individual beetles capture and roll away fungal pieces, which can be the object of energetic scuffles.

Schaeffer (1915) did not indicate the number of specimens on hand for his description of M. punctaticollis . The NMNH entomology database (https://collections.nmnh.si.edu/search/ento/) records a specimen designated as holotype, which was not available for this study. Moreover, I was unable to examine holdings there for other possible syntypes and, so, reserve opinion about the status of the putative holotype.

The uniquely smooth sculpture of the head and pronotum of this species makes for rather easy identification of M. punctaticollis . I have seen a single specimen from Ocala National Forest (Marion Co., Florida) with parameres similar to those of M. bispinatus , which I consider its nearest relative.

Figures

Figure 15. Approximate distributions of species of Melanocanthon.

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 20–26. Melanocanthon punctaticollis (Schaeffer).20) Dorsal view of head.21) Same, deformed head margin. 22) Dorsal view of pronotum. 23) Apical view of parameres. 24) Caudal view of pygidium. 25) Dorsal view of left elytron. 26) Lateral view of metatarsus.