Dipropus asper (LeConte)

Mathison, Blaine A. & Johnson, Paul J., 2017, A new species of Dipropus Germar (Coleoptera: Elateridae) from Florida, with taxonomic and morphological notes and a new key to the species of the eastern United States, Insecta Mundi 2017 (566), pp. 1-7 : 4-6

Dipropus asper (LeConte)

( Fig. 3)

Anchastus asper LeConte, 1878:104 Ischiodontus granosus Fall, 1925:180 new synonym

LeConte (1878) described A. asper from Cedar Keys, Levy Co., Florida. Fall (1925) described I. granosus from three specimens from Palm Beach County and Hog Island, Sumter Co., Florida (the holotype coming from the former), but evidently made no comparison to A. asper . Fattig (1951) and Peck and Thomas (1998) recorded both species from Georgia. The holotypes of both species (MCZ) were examined. The two types are superficially similar externally, with the type of I. granosus being a slightly more robust, paler in color, and having denser pronotal vestiture. The aedeagi, however, are essentially identical. Clark (1963) used the presence ( I. granosus ) or absence ( A. asper ) of a row of strong spines on tarsomere I, and the size of the membranous tarsal pads to separate the two species. An examination of the types of both species shows that these spines (thick, more heavily sclerotized setae) are present in the type of A. asper as well. Examination of nearly 200 specimens identified as either A. asper or I. granosus show that the size and prominence of these spines is variable and the spines, as to be expected in a fossorial species, may be prone to breakage and denuding. Other external characters, such as body size, pronotal shape, color, density of vestiture, and size of the membranous tarsal pads also appear to vary among individuals, with no correlation between one character or another. The most consistent character is the aedeagus, which differs only in size correlating roughly to the overall size of the specimen. Different morphotypes were also collected at the same locality. We hereby designate I. granosus as a new synonym of D. asper . At the time of their descriptions, neither the female of D. asper nor I. granosus were known. Clark (1963) did not mention the females for either species. We describe here the female of D. asper based on two specimens from Franklin and Highlands Counties, Florida.

Description of female of D. asper ( Fig. 3). Body length 5.8–5.9 mm, width 1.9 mm wide; robust, convex, laterally subparallel; integument red-brown, pronotum slightly lighter than elytra; appendages concolorous with body; vestiture long, dense, yellow-gray in color.

Head with frons densely punctate, punctures shallow, umbilicate, separated by a distance less than their diameter; frontal margin formed by supra-antennal carinae complete, broadly rounded in dorsal view; eyes present but smaller than in male, partially concealed by both the frontal area of the head and the anterior margin of the pronotum; antennae very short, not reaching mid-length of pronotum, antennomere 1 long, antennomeres 2–11 short, rounded, moniliform.

Pronotum subquadrate, slightly wider than long, 1.5 mm long by 1.7 mm wide, slightly shiny, densely punctate, punctures shallow, umbilicate, separated by a distance less than their own diameters; hind angles very slightly divergent, unicarinate, carina short, not reaching base of hind angle and gently curving along lateral margin; hypomeron and prosternum sparsely punctate, punctures very shallow, umbilicate; prosternal sutures closed; prosternal process sharply reflexed upwards.

Elytra with strial punctures large, narrowly separated; intervals distinctly punctured, granulose; conjointly rounded at apex.

Metathoracic wings present, not folded, just reaching the last abdominal tergite.

Legs shorter than in male; row of stout spines on tibia and tarsomeres 1–3; tarsomeres shorter than in male, tarsomeres 2–3 lacking membranous lobes; claws simple.

Material examined. Car [r]abelle [sic] Beach, Franklin Co. FL, 7 July 1982, M. & S. Deyrup /coastal scrub habitat / Dipropus asper (LeConte) , det. B. Mathison 2013 (1, ABSC) ; FL: Highlands Co., Archbold Biol. Sta., 14 May 1996, M. Deyrup / Head-down, about 4 mm below surface of sand, in copula with male (1, ABSC) .

Discussion. Both specimens were found associated with males, with the Highlands County specimen found in copula. The female possesses brachypterous metathoracic wings, not longer than the elytra. Other distinctive features of the females such as the shorter legs and tarsi and reduced eyes and antennae are seen in the females of other psammophilous elaterids from the southeastern and southern Coastal Plains (e.g. Floridelater americanus (Horn) and Selonodon spp. ). The lack of membranous lobes the tarsomeres and the proportionately large tibial spines, brachypterous metathorax, and the stout body form, and the collecting situations suggest that the females of D. asper are most-likely generally flightless and are adapted to subterranean activity in sandy substrates.