americanus
Creators: name: ROBERTO CALDARA
name: CHARLES W. O'BRIEN
name: MASSIMO MEREGALLI
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Curculionidae

description: Key to the genera and subgenera of Bagoini
1. Scrobe not reaching eye and squamose (Fig. 1 A). Prosternum without rostral canal and without transverse ridge at its base (Fig. 3 A)......................................................................... Hydronomus Schoenherr
- Scrobe reaching eye and glabrous (Figs 1 B–D). Prosternum with weak (Fig. 3 B) to deep rostral canal (Fig. 3 C); if rostral canal lacking then prosternum with transverse ridge at base (Fig. 3 D).................................................2
2. Rostrum in lateral view strongly curved (Fig. 1 B); apex of rostrum with a lateral plica (Fig. 1 F); basal 2/3 of lateral margin of rostrum (close to ventral margin) with a row of sparse, regularly distributed setae (Fig. 1 F). Apodemes of spiculum ventrale fully bifurcate, arising laterally on plate of sternite, apparently forming two straight rods with arms (Fig. 8 F).................................................................................. Memptorrhynchus Iablokoff-Khnzorian
- Rostrum in lateral view moderately curved to almost straight; apex of rostrum without a lateral plica; basal 2/3 of lateral margin of rostrum with sparse and irregularly distributed setae. Apodemes of spiculum ventrale not bifurcate (Figs 8 E and 8G).3
3. Body short and broad-oval; very small in size, 2.0 mm or less in length (rostrum excluded). Pronotal disc moderately to strongly transversely convex. Postocular lobe ventrally indistinct, not raised, not forming discontinuity with anterior prosternal margin. Prosternal canal weak. Lateral margins of prosternal canal barely raised. Elytra subquadrate (Fig. 4 A), with posterior
declivity in lateral view strong at 75 degrees (Fig. 4 B); declivital callus absent on interval 5 (Fig. 4 A); scales of elytral intervals arranged in almost regular pairs, side by side, each interval with two, individually distinct rows of round scales; vestiture with a semicircular white stripe at posterior third (Fig. 4 A).................................... Azollaebagous n. gen. - Species without all these characters taken together. Postocular lobes well-developed; prosternum with deep rostral canal and with lateral margins well-developed (Fig. 3 C), except for B. geniculatus group of Bagous subgen. Macropelmus (Fig. 3 D)..4
4. Vestiture of odd-numbered elytral intervals generally tessellate, with alternate rectangles of dark and pale scales, or completely whitish. Elytra lacking declivital callosities. Tibiae stout, with inner margin weakly bisinuate. Outer margin of tibiae, especially on hind tibiae, straight or nearly so toward apex (in lateral view). Tarsi short, with tarsomere 3 broadly cordate to subcordate (Fig. 2 F). Basal sclerite complex of endophallus with two pairs of subclavate sclerites variously articulated (Fig. 5 C–D). In female apodemes of spiculum ventrale very broadly and arcuately divergent from base (U-shaped) (Fig. 8 G), and bursa with digitate sclerotized structure (Fig. 8 I)........................................ Bagous subgen. Parabagous Schilsky
- Vestiture of odd-numbered elytral intervals with different pattern. Elytra usually at least with a weak to strong callus at the declivity of interval 5 (Figs 3 F–G). Tibiae usually longer and with inner margin distinctly bisinuate. Outer margin of tibiae, especially on hind tibiae, more or less curved toward apex (in lateral view). Tarsi longer, rarely with tarsomere 3 subcordate. Basal sclerite complex of endophallus, if present, differently shaped. In female apodemes of spiculum ventrale not broadly and arcuately divergent from base (Fig. 8 E), and bursa rarely with sclerotized structure and when present not digitate.........5
5. Rostrum flattened at apex and with dorsal surface at point of antennal insertion distinctly angulate (Fig. 1 D). Scrobe in dorsal view visible for its entire length (Fig. 1 G). Forehead with tuberculate elevation along margin of eye. Pronotum long, 0.90x or more as long as broad. Elytra always elongate................................ Bagous subgen. Hydronoplus Fairmaire
- Rostrum regularly convex from base to apex and with dorsal surface at point of antennal insertion not angulate. Scrobe in dorsal view visible at last in its basal portion (Fig. 1 E). Forehead without tuberculate elevation along margin of eye. Pronotum shorter. Elytra from short to long.........................................................................6
6. Penis with apodemes long, at least half as long as body (Figs 5 A–H).............................................7
- Penis with apodemes short, at most one-third as long as body (Figs 6 B–G, 7A–I and 8A–D).................................................................................................. Bagous subgen. Macropelmus Dejean
7. Orificial lateral sclerites of penis body not reaching anterior margin of orifice (Figs 4 A–B, D–E). Endophallus without subbasal pair of dense concentrations of fine elongate spicules. Base of endophallus without sacule containing elongate, curved spicules. Penis body at apex at most with short narrow lip, widest at base, thence slightly tapered at least in basal 2/3 (Figs 5 E– F, 5G). Tegmen with long parameroid lobes................................................. Bagous Germar s. str.
- Orificial lateral sclerites of penis body reaching anterior margin of orifice. Endophallus with sub-basal pair of dense concentrations of fine elongate spicules (excluding B. pauxillulus). Base of endophallus with sacule containing elongate, curved spicules forming dark, somewhat paired masses (except B. blyxae and B. matthewsi) (Fig. 6 A). Penis body at apex with distinct broad lip, more or less parallel-sided in basal 2/3 (Fig. 6 A). Tegmen with very short parameroid lobes.......................................................................................... Bagous subgen. Hydrillaebagous n.subgen.
description: Published as part of ROBERTO CALDARA, CHARLES W. O'BRIEN & MASSIMO MEREGALLI, 2017, A phylogenetic analysis of the aquatic weevil tribe Bagoini (Coleoptera: Curculionidae) based on morphological characters of adults, pp. 1-63 in Zootaxa 4287 (1) on pages 49-50, DOI: 10.11646/zootaxa.4287.1.1, http://zenodo.org/record/829051