Toctoc asymmetricus Casari

Casari, Sônia A., 2014, A New Genus and a New Species of Dicrepidiina (Coleoptera: Elateridae: Elaterinae: Ampedini) from Brazil, The Coleopterists Bulletin 68 (3), pp. 391-397 : 392-397

Toctoc asymmetricus Casari , new species ( Figs. 1–42 )

Description. Length of holotype ( Fig. 41 ) 16.5 mm; paratypes 12–18 mm. Integument reddish brown to dark reddish brown; legs and antennae lighter than body. Pubescence thin, long, yellowish, and dense, slightly shorter and sparser on elytra; antennae with pubescence short and very dense, longer, denser, and more bristly on male. Head: Frons ( Figs. 1 , 39, 40 ) longer than wide in male and as long as wide in female; declivous with a strong triangular concavity at middle near anterior margin; carinate only laterally at antennal insertions; punctation heterogeneous, coarse and dense. Nasale high, dense and coarsely punctate, continuous with frons, slightly convex. Antennae ( Figs. 4, 5 , 41 ) serrate, stronger in male; 2 or 3 antennomeres longer than apices of hind angles of pronotum in male and not reaching apices of hind angles in female; antennomeres 3–10 very prominent and sharpened laterally in male and rounded in female; antennomere 2 globular; antennomere 3 triangular, longer than 2 and shorter than 4; antennomeres 4–10 longer than wide in male and as long as wide or wider than long in female; antennomere 11 elongate in both sexes. Labrum ( Figs. 2 , 39 ) elliptical with setae long and dense on anterior 2/3. Epipharynx ( Fig. 3 ) densely covered with thin setae; with 1 triangular sclerite on each side near middle, and several campaniform sensilla and 1 seta at middle near base. Mandible elongate with sharpened apex; asymmetrical in both sexes; right mandible ( Figs. 8–11 ) with wide tooth with bilobate apex near middle of mesal margin; left mandible ( Figs. 12, 13 ) with small tooth near middle of mesal margin; both mandibles with long setae dorsolaterally and with penicillus formed by short setae. Maxilla ( Fig. 7 ) with cardo triangular with 4 setae near base; basistipes rectangular with latero-external margin slightly rounded, densely covered with long setae of varied lengths; mediostipes irregularly elongate with longitudinal carina, setae moderately long near carina, and sensilla near apex; galea and lacinia longer than wide with apex wide and rounded, densely covered by thin, yellowish setae; lacinia with sclerite near base. Palpifer densely setose, with long setae; palpi densely setose and with 4 palpomeres; basal palpomere globular; palpomeres 2–3 elongate and slightly widened apically; distal palpomere elongate, more strongly widened at apex. Labium ( Fig. 6 ) with prementum membranous; ligula notched at middle, with long setae near anterior margin; palpiger densely covered by setae of varied sizes; mentum wider than long, slightly narrowed anteriorly and translucent in a transverse narrow anterior band; with setae of varied sizes, some very long; gula with irregular band of long setae near base and short setae forming irregular band near anterior and basal margins. Labial palpi setose and with 3 palpomeres; basal palpomere short; palpomeres 2– 3 elongate and widened apically. Thorax: Pronotum ( Figs. 18 , 41, 42 ) wider than long, strongly convex; lateral margins not visible dorsally, sinuous when seen laterally; anterior margin slightly prominent at middle, margined by narrow raised smooth band; lateral margins almost straight; hind angles long, wide and divergent with a single strong and wide carina near lateral margins; apices of hind angles rounded and directed ventrally; punctation strongly coarse, very dense and heterogeneous, coarser laterally; grooved and impunctate longitudinally medially at basal third and transversally at base of hind angles; posterior margin with a raised, rounded notch at middle. Hypomeron ( Figs. 16, 17 ) narrow, lateral sutures of pronotum displaced ventrally; lateral margin slightly sinuous; punctation coarse and dense; basal fourth smooth with inclined grooves. Pronotosternal sutures ( Figs. 16, 17 ) sinuous, margined by narrowly raised, smooth band continuous on anterior margin of hypomeron; opened anteriorly but not forming a groove. Prosternum short, convex, dense, coarsely and irregularly punctate; punctation coarser than that on hypomeron; prosternal lobe shorter than anterior margin of hypomeron, grooved at base; fore angles of prosternal lobe margined. Prosternal spine ( Figs. 16, 19 ) convex and curved between procoxae; compressed laterally behind procoxae; apex sharpened with subapical, almost straight tooth. Mesosternal cavity ( Figs. 16, 19 ) narrow between mesocoxae; declivous with borders narrow, raised at basal region; mesepimeron and mesepisternum forming wall of mesosternal cavity; mesotrochantin visible. Metasternum convex, flattened longitudinally medially; densely punctate; punctation smaller than that on pronotum; discrimen grooved, well-marked. Metacoxal plate ( Fig. 14 ) short, gradually narrowed laterally; posterior margin straight. Scutellum elongate, gradually narrowed on distal half; anterior margin and apex rounded. Hind wing ( Fig. 15 ) 2.7 times as long as wide; radial cell (R) well-developed; radial vein curved and translucent basally; wedge cell present; apex of wing membrane with 3 sclerotizations fused at base, forming a ɯ- like shape. Elytra long, 3.25 times longer than pronotum; strongly convex, narrowed on distal fourth; punctate-striate; striae marked by row of punctures inside narrow groove; interstices slightly convex and irregularly punctate, giving a rugose appearance. Tibiae and tarsi ( Figs. 30, 31, 35, 36 ) densely clothed with spiniform setae; tibial spurs well-developed; tarsomeres 1–3 lamellate beneath; lamellae increasing in size apically. Claws asymmetrical in male ( Figs. 32–34 ); external claw short and widened at basal half in male; both equal and sharpened in female ( Figs. 37, 38 ). Abdomen: Ventrites I–IV densely punctate; punctation moderately small; ventrite V elongate, narrowed apically; apex narrow and rounded; distal third roundly convex with punctation and pubescence denser, giving a slightly rugose appearance. Intersegmental membrane between ventrites IV and V distinct; ventrite V very moveable and usually kept ventrally directed. Male: Tergite VIII ( Fig. 24 ) slightly wider than long, slightly narrowed apicad; apex rounded and slightly notched at middle; translucent in triangular basal area; pubescence longer and denser near lateral and anterior margins. Sternite VIII ( Fig. 25 ) band-like, translucent with transverse narrow sclerite at base; narrowed near base and on distal third; anterior margin widely notched at apex forming 2 rounded lobes; setae moderately long near lateral and anterior margins. Tergite IX ( Fig. 27 ) wider than long, gradually narrowed apicad; distal margin strongly notched at middle forming 2 wide rounded lobes; setae of varied sizes laterally; short setae near middle. Tergite X ( Fig. 27 ) narrower than tergite IX, elongate, gradually narrowed apicad; apex rounded; long setae present laterally and anteriorly. Sternite IX ( Fig. 26 ) elongate, narrowed on distal third; setae moderately long on distal third. Aedeagus as in Figs. 28, 29 ; basal piece longer than parameres dorsally; parameres with apex rounded and subapical lateral small tooth; setae at apex dorsally and ventrally; median lobe longer than parameres, wider near base and narrowed apicad, constricted at subapical region; basal struts shorter than basal piece. Female: Tergite VIII ( Fig. 20 ) wider than long, triangular with angles rounded; translucent at median basal region and in a narrow marginal band; setae moderately long and dense, longer near margins. Sternite VIII ( Fig. 21 ) translucent with elliptical sclerotized median area; densely covered by setae; baculum about 2.7 times sternite length. Ovipositor ( Figs. 22, 23 ) with styli with 4 long and 1 short seta at apex; bursa copulatrix without spines or sclerotized plates.

Type Material. Holotype (male). Brasil (MA) [Maranhão], Mirador, Parque Est.[adual] Mirador, Base de Geraldina (06°37′25″S 45°52′08″W). Armadilha Luminosa, 07-14.III.2013, F. Limeirade-Oliveira, A. A. Silva & C. F. Barros ( CZMA) . Paratypes. Females (2 specimens). Brasil (MA), Mirador , Parque Est. Mirador , Posto Avançado do Mel (06°43′50″S 44°58′59″W). Armadilha Luminosa, 02-08.IV.2011, F. Limeira-de-Oliveira, G. A. Reis & M. S. Oliveira cols ( MZSP, dissected). Idem, 18-25.III.2012, F. Limeira-de-Oliveira, T. T. A. Silva & T. M. A. Lima cols ( CZMA). Males (36 specimens) . Brasil (MA), Mirador , Parque Est. Mirador, Base de Geraldina. Armadilha Luminosa, 22.II-01.III.2008, M. B. Aguiar-Neto & M. J. A . Holanda cols. ( CZMA, 2 specimens; MZSP, 4 specimens). Idem , 08-13.III.2008, F. Limeira-de-Oliveira, J. C. Silva ( MZSP). Idem, 07-14.III.2013, F. Limeira-de-Oliveira, A. A. Silva & C. F. Barros ( CZMA) . Brasil (MA), Carolina , Prov. [incia] Canto Grande, Balneário Urupuxete. Armadilha Luminosa, 23-27.II.2009, F. Limeirade-Oliveira, A. L. Costa & M. M. Abreu cols ( CZMA, 1 specimen; MZSP, 2 specimens: 1 dissected) . Brasil (MA), Mirador , Parque Est. Mirador, Base do Mosquito. Armadilha Luminosa, 04-08. II.2011, F. Limeira-de-Oliveira ( CZMA) . Brasil (MA), Mirador , Parque Est. Mirador , Posto Avançado do Mel. Armadilha Luminosa, 02-08. IV.2011, F. Limeira-de-Oliveira, G. A. Reis & M. S. Oliveira cols ( CZMA, 4 specimens; INPA, 1 specimen.; UFMT, 1 specimen; MNRJ, 1 specimen.; MZSP, 5 specimens). Idem, 18-25.III.2012, F. Limeira-de-Oliveira, T. T. A. Silva & T. M. A. Lima cols ( CZMA, 4 specimen; INPA, 1 specimen.; UFMT, 1 specimen; MNRJ, 1 specimen; MZSP, 5 specimens) .

Etymology. The specific epithet is a derivative of the Latin word asymmetricus (= asymmetric), referring to the asymmetry of the claws of the male and mandibles of both sexes.

Remarks. Toctoc asymmetricus is characterized by the serrate antennae, stronger in the male; third antennomere triangular, longer than the second and shorter than the fourth; frons with a triangular concavity, strongly concave near the anterior margin; mandibles asymmetrical in both sexes; claws asymmetrical in the male; intersegmental membrane between ventrites IV and V welldeveloped, permitting enhanced mobility of ventrite V; basal piece of aedeagus longer than the parameres; bursa copulatrix without sclerotized pieces.

Toctoc asymmetricus is similar to T. varians , especially by the absence of a pronotosternal groove, borders of the mesosternal cavity declivous, posterior margin of the metacoxal plate straight, tarsomeres 1–3 lamellate beneath, and bursa copulatrix without teeth or sclerotized plates. But these two monotypic genera are easily separate by the following: frons longer than wide in male and as long as wide in female (wider than long in female T. varians ); carina of frons well-marked and present only laterally above antennal insertions (almost complete but weak at middle in T. varians ); nasale high and continuous with frons (short and separated by weak carina or continuous with frons in T. varians ); mandibles asymmetrical in both sexes (symmetrical in T. varians ); lateral margin of pronotum not visible dorsally, displaced ventrally (visible dorsally in T. varians ); claws asymmetrical in male (symmetrical in T. varians ).

One character that is rare in most Dicrepidiina but present in T. asymmetricus is the membranous bursa copulatrix without spines or sclerotized plates. Among the Dicrepidiina whose genitalia are known, this form of the bursa copulatrix is present, aside from T. varians , only in some species, including Achrestus venustus Champion, 1895 [ Achrestus flavocinctus (Candèze, 1859) has spines], Cyathodera longicornis Blanchard, 1846 , Proloboderus crassipes Fleutiaux, 1912 , Pseudolophoeus guineensis (Candèze, 1881) , and all known species of Loboderus Guérin-Méneville, 1831 .

Among the known Elaterinae, the tribe Odontonychini Girard, 1972 , is characterized by having one claw of each tarsus bifid in males and both single and attenuate in females. This tribe is known only from Africa and includes three genera that, together with Semiotopsis (Ampedini, Dicrepidiina ), are the only taxa with asymmetrical claws in this subfamily.

Figures

Figs. 1–15. Toctoc asymmetricus. Male: 1) Frons; 2) Labrum; 3) Epipharynx; 4–5) Antenna (male, female, respectively); 6) Labium; 7) Maxilla; 8–11) Right mandible (ventral, dorsal, external, internal views, respectively); 12–13) Left mandible (dorsal, ventral views, respectively); 14) Metacoxal plate; 15) Hindwing. Bars = 1 mm, except Figs. 2, 3, 6, 7 = 5 mm.

Figs. 16–29. Toctoc asymmetricus. Male: 16) Thorax (lateral view); 17) Pronotosternal suture; 18) Pronotum; 19) Prosternal spine and mesosternal cavity; 24) Tergite VIII; 25) Sternite VIII; 26) Sternite IX; 27) Tergites IX–X; 28–29) Aedeagus (dorsal, ventral, views, respectively). Female: 20) Tergite VIII; 21) Sternite VIII; 22) Ovipositor and bacilli; 23) Ovipositor. Bars = 10 mm, except Figs. 16–19 = 1 mm; Figs. 22, 28, 29 = 5 mm; Fig. 23 = 2 mm.

Figs. 30–42. Toctoc asymmetricus. Male: 30–31) Posterior leg (external, internal views, respectively); 32–34) claws (frontal, latero-external, latero-internal views, respectively). Female: 35) Tibia and tarsus; 36) Tarsus; 37–38) Claws (frontal, lateral views, respectively); 39–40) Frons (frontal, lateral views, respectively). Habitus: 41) Male (holotype); 42) Female. Bars = 30 mm, except Figs. 30, 35 = 100 mm; Figs. 31, 36 = 20 mm; Fig. 38 = 20 mm; Figs. 41–42 = 5 mm.