Balgus eschscholtzi ( Laporte, 1835 )

Barbosa, Felipe Francisco, 2016, Revision and phylogeny of the genus Balgus Fleutiaux, 1920 (Coleoptera, Elateridae, Thylacosterninae), Zootaxa 4083 (4), pp. 451-482 : 458-460

Balgus eschscholtzi ( Laporte, 1835)

( Figure 4 )

Pterotarsus variegatus Dejean, 1837: 95 - Bonvouloir, 1875: 843 (in litteris).

Pterotarsus Eschscholtzi Laporte, 1835: 175 (original description); Guérin-Méneville, 1843: 196; Bonvouloir, 1875: 832, 843 (redescription).

Balgus Eschscholtzi Fleutiaux, 1920: 97 (new combination); Schenkling, 1928: 7 (catalogue).

Balgus eschscholtzi Blackwelder, 1944: 275 (catalogue, correction of the specific epithet under the article 32.5.2.5 of ICZN, Eschscholtzi to eschscholtzi ).

Diagnosis. Subcylindrical body ( Figures 4A, B, C, F ); dorsal and ventral regions covered with yellow or golden pubescence, denser on light brown or yellow elytral bands and elytral apex; anterior half of the pronotum and elytra without tubercles.

Redescription. Subcylindrical body, narrowing abruptly on the posterior fourth. Elytra about two and a half times as long as pronotum. Dorsal and ventral region covered with yellow or golden pubescence, much denser in light brown or yellow elytral bands and elytral apex.

Color: shiny black except for first and second antennomeres dark brown, other antennomeres light brown; antennal rami yellow; legs dark brown; tarsi light brown or yellow. Elytra with two light brown bands: basal band discontinuous, originates at middle of elytra, then extends towards the apex, curving towards base to suture; apical band originates next to basal band, on elytral margin, extending towards apex, up to suture.

Head ( Figure 4D ): densely punctate, with deep longitudinal median anterior depression, continues posteriorly on longitudinal groove on vertex, not V-shaped. Eye with spherical surface in lateral view, dorsal margin not sinuous.

Thorax: subcylindrical prothorax ( Figures 4A, B, C, F ), almost as long as wide; slightly sinuous margins; tubercles short and conspicuous; posterior half of pronotum with posterolateral rounded tubercle and posteromedian rounded tubercle; anterior half of pronotum without tubercles. Pronotal sculpture formed by deep punctations. Narrow scutellum, rounded, slightly longer than wide, carinate. Lateral thoracic sclerites hidden under elytra. Antennal acetabulum very deep next to prosternal process. Prosternal process gradually attenuate towards posterior margin; more or less straight. Prosternum, mesoventrite and metaventrite densely punctate. Elytra ( Figures 4A, C, F ) finely and sparsely punctate; subacuminate apex; without raised stria; without tubercles.

Abdominal ventrites: densely punctate; ventrite 5 ( Figure 4E ) triangular, with longitudinal median carina, forming four small teeth; strong and gradually narrowed from base to apex, which truncated, not curved.

Female genitalia ( Figure 4G ): baculum about 6.5 times as long as coxite; baculi, at least in apical third, separated by approximately twice a baculum. Coxites without setae.

Aedeagus ( Figures 4H, I, J ): paramere tapering as it approximates to the apex; rounded at apex, with many setae. Penis tapering apically; acuminate at the apex, in lateral view slightly curved ventrally. Phallobasis nearly as long as parameres; about three times as wide as parameres. Concavity of the phallobasis, in dorsal view, expanded next to the base towards the apex, reaching the limit of the parameres.

Intraspecific variation: size variation (N = 19): length 9.40–13.50 mm (mean = 11.10 mm); humeral width 3– 4.70 mm (mean = 3.65 mm).

Remarks. Balgus eschscholtzi is similar to B. albofasciatus , but differs in the following characters: B. albofasciatus lacks a carina on the scutellum; has white to silver setae; bears a short oblique carina on the posterior angle of the pronotum; basal fifth of the elytra with four high longitudinal stria and without transverse rugosities. The aedeagus of B. eschscholtzi is significantly different from the other species of Balgus , so that is the only known species with a phalobasis about as long as the parameres and with the apex rounded, rather than acuminate.

Etymology. [Eschscholtz declined in dative mode]. In honor of entomologist J. F. von Eschscholtz.

Material examined. 2 exs., Bolivia, Santa Cruz, Santiago de Chiquitos , 700 m, X/1958, F. W. Waltz col., I.G.: 22.353, IRSN ; 1 ex., Bolivia, Santa Cruz, 3,7km, SSE. Buena Vista, Hotel Flora & Fauna, 430m, 10–29/XI/2003, B. K. Dozier col., black light trap, FDACS ; 4 exs., Brazil, Goiás (GO), Jataí, E. Fleutiaux coll., MNHN ; 1 ex., Brazil, Goiás (GO), Jataí, IX – XI/1997, E. Fleutiaux coll., MNHN ; 1 ex., Brazil, Goiás (GO), Rio Verde , IX– XI/ 1997, E. Fleutiaux det., A. Sicard coll., MNHN ; 1 ex., Brazil, Goiás (GO), A. Sicard coll., MNHN ; 1 ex., Brazil, Mato Grosso (MT), I.(illegible), W. (illegible) col., XI/192(illegible), MNRJ ; 1 ex., Brazil, Minas Gerais (MG), Belo Horizonte, R. L. Araújo col., 20/XII/1951, A. Cobos det., IBSP ; 1 ex., Brazil, Minas Gerais (MG), Belo Horizonte, R. L. Araújo col., 20/XII/1951, A. Cobos det., 1972, IBSP ; 1 ex., Brazil, Minas gerais (MG), Ipatinga, A. M. Bello col., XI/1994, FIOCRUZ; 1 ex., Brazil, Minas Gerais (MG), Mar de Espanha , J. F. Zikán col., 19/XII/ 1969, J. F. Zikán coll., MNRJ ; 1 ex., Brazil, Minas gerais (MG), Lavras, F. Z. Vaz-de-Mello col., XI/2002, FIOCRUZ; 1 ex., Brazil, Rio de Janeiro (RJ), Itatiaia, W. Zikán col., II/1959, MNRJ ; 1 ex., Brazil, Rio de Janeiro (RJ), Nova Friburgo, Macaé de Cima, E. Grossi col., XII/2009, Coleção A. M. Bello, FIOCRUZ; 2 exs., Brazil, Rondônia (RO), 62 Km SW., Ariquemes, nr. Fazenda Rancho Grande, 5–17/X/1993, J. E. Eger col., black light trap, FDACS ; 1 ex., Guyana , A. W. Bartlett col., A . W. Bartlett coll., 1943-60, BNHM; 1 ex., Panama, Chiriquí, V. de Chiriquí , 2–8000 ft., Champion col., J. Muona det., 1982, BNHM .

Distribution. Bolivia, Brazil (GO, MG, MT, RJ & RO), Guyana and Panama ( Figure 12 ).

Type locality. Brazil.

Figures

FIGURE 4. Balgus eschscholtzi (Laporte, 1835): A) habitus, dorsal view; B) habitus, ventral view; C) habitus, lateral view; D) head, frontal view; E) ventrite 5, ventral view; F) pronotum and elytra, dorsal view; G) female genitalia, dorsal view, apex oriented to the bottom of the page; G) aedeagus, dorsal view; H) aedeagus, lateral view; I) aedeagus, ventral view. The genitalia apex oriented to the bottom of the page. Genitalia scales: 0.5 mm, other scales: 2 mm.

FIGURE 12. Geographical distribution of Balgus albofasciatus (Bonvouloir, 1875), Balgus eganensis (Bonvouloir, 1875) and Balgus eschscholtzi (Laporte, 1835).