Megadytes (Bifurcitus) magnus Trémouilles & Bachmann, 1980

Hendrich, Lars, Manuel, Michael & Balke, Michael, 2019, The return of the Duke - locality data for Megadytes ducalis Sharp, 1882, the world's largest diving beetle, with notes on related species (Coleoptera: Dytiscidae), Zootaxa 4586 (3), pp. 517-535 : 525-529

Megadytes (Bifurcitus) magnus Trémouilles & Bachmann, 1980

Megadytes (Bifurcitus) magnus Trémouilles & Bachmann, 1980: 118 (orig. descr.); Trémouilles 1989b: 161; Miller & Bergsten 2016: 108; Nilsson & Hájek 2019: 81.

Type locality. Argentina, Santa Fe .

Type material examined. Paratype: 1 male, " Argentina: S. Fe Ceres III.1943 leg. Polmer " [handwritten label], " PARATYPUS " [red printed label], "Brit. Mus. 1989-185" [printed label], " Col. A.O. Bachmann " [printed label], " Megadytes (Bifurcitus) magnus E.R. Tremouilles y A.O. Bachmann ano 1979" [red handwritten label] ( BMNH) .

Other material examined. Paraguay : 1 male, 2 females, " Paraguay / Chaco Dep. Boquéron 10 km SE Mariscal Estigarribia, 2.2.1990, leg. U. Drechsel " (CLH); 4 males, 6 females, " Paraguay / Chaco Dep. Boquéron 10 km SE Mariscal Estigarribia, 10.2.1990, leg. U. Drechsel " ( CLH, ZSM) ; 1 male, " Paraguay / Cerro Lambaré , 5.6.1992, leg. U. Drechsel / Coll. Hendrich " ( CLH) ; 1 male, " Paraguay / Dep. Central , Asunción, 31.10.1991, 5.6.1992, leg. U. Drechsel / Coll. Hendrich " ( CLH) ; Brazil: 1 female, " Brasilien , Sao Paulo, 10.12.1984, in swimming pool, Gottwald leg." ( CLH) .

Descriptive notes. A description of this species was given by Trémouilles & Bachmann (1980). Here we provide photos of the habitus ( Figs 1C, F , 2C ) and focus on morphological characters of the male in different views ( Figs 8 D–F). The median lobe with both parameres of a specimen from Mariscal Estigarribia in Paraguay, is figured in ventral view ( Fig. 6A ), the tip of the median lobe in lateral view ( Fig. 6B ), and the tip of median lobe in ventro-apical view ( Fig. 6C ). Note that Figs 6A and C show the median lobe of the same individual, tilted at different angles.

Distribution. Southern part of tropical and subtropical South America. The species was described from Argentina, Paraguay and Uruguay, and later recorded from Brazil (Trémouilles 1989b) ( Fig. 11 ).

Habitat. Unknown, probably similar to M. lherminieri . Most of the specimens in Paraguay were collected at light in a savannah region with temporary swamps and permanent farm dams. The swimming pool in Sao Paulo, were the single female has been collected, was not far away from a big reservoir or dam, overgrown with water lilies and water hyacinths (S. Gottwald pers. com.).

Figures

FIGURE 1. Habitus in dorsal view of: A) M. ducalis, B) M. lherminieri, C) M. magnus; habitus in ventral view of: D) M. ducalis, E) M. lherminieri (Ecuador, Esmeraldas), F) M. magnus (Paraguay, Cerro Lambaré).

FIGURE 2. Habitus in lateral view of: A) M. ducalis, B) M. lherminieri, C) M. magnus.

FIGURE 6. Megadytes magnus: A) median lobe with parameres in ventral view, B) tip of median lobe in lateral view, C) median lobe in ventro-apical view to show the long nose-like tip. Scale bars = 1.5 mm.

FIGURE 8. Megadytes lherminieri, male, Ecuador, Esmeraldas: A) ventral view of head, left protarsus and left middle leg, B) dorsal view of left protarsus, C) ventro-lateral view of left hind leg; M. magnus, male, Paraguay, cerro Lambaré: D) ventral view of head, right protarsus and right middle leg, E) dorsal view of left protarsus, F) ventro-lateral view of left hind leg. Scale bars = 5 mm.

FIGURE 11. Distribution of the subgenus Bifurcitus in Central and South America: White line: distribution of M. lherminieri; black line: distribution of M. magnus; red spot: only known locality for M. ducalis.