Tetralimonius, Etzler, 2019

Etzler, Frank E., 2019, Generic Reclassification of Limonius Eschscholtz, 1829 (Elateridae: Dendrometrinae) sensu Candèze 1860 of the World, Zootaxa 4683 (3), pp. 301-335 : 327-328

5. Tetralimonius new genus. 7 species

Type species: Limonius ornatulus LeConte, 1857: 46 .

Nearctic species (5)

Tetralimonius definitus (Ziegler, 1845) : 268 ( Limonius ) new combination.

Tetralimonius humeralis ( Candèze, 1860) : 402 ( Limonius ) new combination, removed from synonymy.

Tetralimonius maculicollis (Motschulsky, 1860) : 372 ( Limonius ) new combination, removed from synonymy. Limonius discicollis Candèze, 1865: 49 .

Tetralimonius nimbatus (Say, 1825) : 265 ( Elater ) new combination.

Limonius infernus LeConte, 1853: 434 .

Tetralimonius ornatulus (LeConte, 1857) : 46 ( Limonius ) new combination.

Palearctic species (2)

Tetralimonius quercus (Olivier, 1790) : 51 ( Elater ) new combination.

Pheletes candezei Buysson, 1888 : ccxii.

Elater lythrodes Germar, 1813: 129 .

Limonius nigricollis Schilsky, 1888: 187 .

Pheletes soldrii Buysson, 1902: 284 .

Corymbites testaceus Schilsky, 1888: 187 .

Tetralimonius reitteri ( Gurjeva, 1976) : 195 ( Pheletes ) new combination.

Diagnosis. This genus can be readily differentiated from the other Limonius genus-group members by the short, truncate pronotal hind angles, posteriorly pointed scutellum (Fig. 47), nearly closed pronotal coxal cavities (Fig. 48), female uterus bearing two spinose sclerotizations (Fig. 50, inset), and the parameres of the male adeagus lacking apical expansions (Figs. 51–53). Tetralimonius is most similar to Pheletes , which shares a sub-pentagonal scutellum, but differs in all other characters that diagnose Tetralimonius . Pheletes species also have simple and sparse pronotal punctation laterally, whereas all Tetralimonius species have umbilicate and close lateral pronotal punctation.

Tetralimonius species possess a partially closed mesocoxal cavity (Fig. 49), similar to genera in the tribe Hypnoidini . This character is also shared by some species in Limonius , including the type species (Fig. 25), and species in Pheletes . This character should be reevaluated as to its usefulness in defining genera or tribes (e. g. Kishii 1987).

Description. Testaceous to piceous, pronotum and elytra often distinctly bicolored, relatively small, around 3.5–7mm in length, dull to shining. Head with umbilicate and close punctures; frons flat to subtly impressed; frontal margin entire, narrowly carinate, straight and weakly projecting. Antennae with 2 nd antennomere subcylindrical, noticably wider than 3 rd and subequal to or slightly longer than 3 rd, 3 rd subcylindrical, shorter than 4 th, sometimes just slightly shorter, ratio of length of 2 nd + 3 rd to 4 th variable, 4 th to 10 th antennomeres weakly serrate, sometimes almost filiform, 11 th ovoid. Pronotum as wide as long, anterior angles not expanded; hind angles wide at base not extending past posterior edge of pronotum, a faint single carina is visible in some species but is parallel and close to lateral pronotal carina as to appear absent at first glance, tip truncate; posterior margin lacking basal incisures and basal notch; prosternal sutures double, weakly grooved anteriorly, but not excavated to receive antennae; posterior margin earlike, not emarginate; prosternal process expanded laterally; procoxal cavities closed posteriorly by expandions of hypomeron and prosternal process so only a line is visible (Fig. 48). Scutellum sub-pentagonal, posteriorly pointed (Fig. 47), relativey flat. Mesepisternum not reaching mesocoxal cavity (Fig. 49). Abdomen with lateral micro-serrations on each ventrite. Legs slender, tarsomeres simple, with dense setal pads ventrally; claws simple, lacking setae. Male genitalia with a narrow aedeagus and parameres lacking apical expansions (Figs. 51–55). Female internal genitalia with uterus bearing two colleterial glands and two spinose sclerotized sections (Fig. 50), bursa copulatrix with narrow tube attaching to uterus, expanding apically, with medial accessory gland, and terminating into long tubular extension with basal accessory gland or diverticulum.

Etymology. The name Tetralimonius is derived from the combination of Tetra - due to the nearly quadrate pronotum possessed by the species in this genus and Limonius to recognize the historic ties to this genus.