Drilus adustus ( Chevrolat, 1854 ) Chevrolat, 1854

Kundrata, Robin, Kobieluszova, Lucie & Bocak, Ladislav, 2014, A review of Drilini (Coleoptera: Elateridae: Agrypninae) of the Northern Levant, with description of a new species from Syria and a key to Levantine species, Zootaxa 3755 (5), pp. 457-469 : 458-459

Drilus adustus ( Chevrolat, 1854) , comb. nov.

( Figs 1 , 7, 13 , 19 )

Malacogaster adustus Chevrolat, 1854: 433 .

Malacogaster adusta: Gemminger & Harold 1869: 1684 (sic). Drilus posticus Schaufuss, 1867: 82 , new synonym.

Material examined. 1 male, Beirut ( MHNP); 1 male, Syria // det. K. G. Blair ( BMNH) [labelled as M. adustus ]; 1 male, Beirut, Staudg. // coll. Reitter ( MHNP); 2 males, Led. 857 // det. Reitt. 1894 ( NHMW); 1 male, Appl Beirut 1878 // det. Reitt. 1894 ( NHMW) [labelled as D. posticus ].

Diagnosis. Drilus adustus resembles D. bicolor in bicolored elytra and lightly colored head and antennae, but differs in having only apical fifth of elytra dark brown to black ( Figs 1, 3 ), longer antennomere 3 ( Figs 7, 9 ), less transverse pronotum with inconspicuous, obtuse hind angles ( Figs 13, 15 ), and larger and shallower pronotal punctures.

Redescription. Male. Body medium-sized, elongate, 2.9–3.2 times longer than width at humeri, moderately convex dorsally ( Fig. 1 ). Whole body yellowish to brown, only apical one fifth of elytra dark brown to black; body covered with yellow pubescence.

Head slightly hypognathous, including eyes about as wide as anterior margin of pronotum. Surface of cranium punctured, without or with very shallow depression between antennal sockets, dorsally with sparse semierect pubescence; clypeal margin slightly concave. Eyes medium-sized, hemispherically prominent, their frontal distance 2.1–2.5 times eye diameter. Mandibles robust, long, falcate, considerably curved, shiny, incisor margin with conspicuous tooth in middle part. Maxillary palpi slender, apical palpomere obliquely cut; labial palpi tiny, apical palpomere pointed. Antennae 11-segmented, reaching one third of elytral length, scapus robust, pedicel short, small, antennomere 3 slightly serrate, about 3 times longer than antennomere 2, antennomeres 4–10 shortly flabellate, subequal in length, lamellae short, flattened, apical antennomere simple, longest, about 2 times longer than stem of penultimate antennomere ( Fig. 7 ).

Pronotum flat, transverse, widest in middle, 1.4–1.6 times wider posteriorly than length at midline. Anterior margin straight, lateral margins convex, posterior margin slightly convex, inconspicuously sinuate medially. Anterior angles almost rectangular, posterior angles obtuse, slightly turned upward ( Fig. 13 ); surface of disc sparsely covered with large, shallow, rounded punctures, with very sparse semierect setae, pubescence denser at margins. Scutellum flat, triangle-shaped, longer than width in middle part, apical part rounded, sometimes basal part of scutellum slightly depressed. Prosternum transverse, with frontal margin almost straight, prosternal process short, slightly elevated in middle part. Mesoventrite v-shaped, with frontal margin widely emarginate. Metaventrite large, trapezoidal, shallowly punctured. Elytra subparallel-sided, widest at humeri, 2.3–2.6 times longer than width at humeri, tapered apically, punctured. Each elytron covered with semierect pubescence, sparse basally and dense at lateral and posterior margins. Abdomen slender, ventrites with fine microstructure and sparse, long hairs, penultimate ventrite slightly emarginate in middle part. Legs slender, slightly compressed, with sparse, long, semierect setae, coxae long, robust, trochanters slender, obliquely attached to femora, tarsomeres 1–3 subequal in length, tarsomere 4 shortest, narrow, apical tarsomere long, claws simple, slender, slightly curved.

Male genitalia with phallus considerably curved, strong; paramerae with apical part membranous; phallobase robust, longer than paramerae ( Fig. 19 ).

Measurements. BL 6.6–9.0 mm, EL 5.3–7.3 mm, WH 2.3–3.1 mm, PL 1.2–1.7 mm, PW 1.7–2.4 mm, Edist 1.0– 1.4 mm, Ediam 0.5–0.6 mm.

Distribution. Lebanon (Saïda: the type locality of D. adustus , Beirut: the type locality of D. posticus ). Baudi di Selve (1871) mentioned that D. adustus (as D. posticus ) occurs also in Cyprus, but we have not found any Cyprian D. adustus in any European collections so far.

Remarks and taxonomic decisions. Drilus adustus was originally placed in Malacogaster ( Chevrolat 1854) . Reitter (1894) transferred M. adustus to Drilus noting that he had not seen any specimen, but his decision was ignored by subsequent authors ( Olivier 1910, Wittmer 1944, Bocak 2007). However, this species should indeed be classified in Drilus due to the presence of the shortly flabellate antennae, convex lateral pronotal margins, and almost complete sharp edges at lateral prothoracic margins ( Reitter 1894, Kundrata & Bocak 2007).

Despite thorough search in the MNHP collection, we have not been able to locate the type material and depend on identified material and descriptions when comparing D. adustus with other Drilus species. We have at our disposal specimens identified by K. G. Blair, M. Pic and E. Reitter as Drilus adustus and D. posticus and they share similar external morphology and shape of male genitalia. As we have not found any further similar species in the region and no distinguishing characters are listed in the original descriptions, we propose to consider D. posticus Schaufuss, 1867 as a junior subjective synonym of D. adustus ( Chevrolat, 1854) .

Figures

FIGURES 1 – 6. General appearance. 1 — Drilus adustus; 2 — D. akbesianus; 3 — D. bicolor; 4 — D. nemethi sp. nov.; 5 — D. rectus; 6 — D. rufipes. Scale 2.0 mm.

FIGURES 7 – 18. Antenna. 7 — Drilus adustus; 8 — D. akbesianus; 9 — D. bicolor; 10 — D. nemethi sp. nov.; 11 — D. rectus; 12 — D. rufipes. Pronotum. 13 — Drilus adustus; 14 — D. akbesianus; 15 — D. bicolor; 16 — D. nemethi sp. nov.; 17 — D. rectus; 18 — D. rufipes. Scale 1.0 mm (Figs 7 – 12), 0.5 mm (Figs 13 – 18).

FIGURES 19 – 24. Male genitalia. 19 — Drilus adustus; 20 — D. akbesianus; 21 — D. bicolor; 22 — D. nemethi sp. nov.; 23 — D. rectus; 24 — D. rufipes. Scale 0.25 mm.