Metallactus hamifer , Suffrian 1866
Creators: name: Sassi, Davide
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Chrysomelidae
Metallactus
Metallactus hamifer

description: Key to the M. hamifer species-group
1. Elytron completely yellow, pronotum yellow with two longitudinal black stripes partly reddish on their posterior half, legs yellow with tarsi blackish.................................................................. M. tarsalis (Fig. 16)
-. Elytron dark with yellow pattern or viceversa, never completely yellow.......................................... 2
2. Elytral pattern yellow with one or two longitudinal darker stripes or dark (sometimes reddish) with two longitudinal yellow stripes. Stripes extended from elytral base to apex or at least to apical clivus....................................... 3
-. Elytral pattern prevalently black with a longitudinal series of rounded or transverse yellow spots or patches. Sometimes yellow patches very large, so that yellow pattern exceeds the black one................................................ 11
3. Elytral yellow with darker pattern consisting of a single large reddish or brownish stripe (rarely elytral stripe broken in a double series of rounded spots). Pronotum yellow with two reddish stripes in continuity with the elytral ones. Species from Bolivia .................................................................................... M. sekerkai (Fig. 15)
-. Elytral yellow or black with longitudinal pattern consisting of two stripes......................................... 4
4. Legs and inferior parts completely black. Pronotum reddish with two large trapezoidal black spots in middle of disc and two smaller rounded ones, black as well, close to lateral margin, elytron black with two narrow yellow stripes coalescent towards apex............................................................................... M. pollinctor (Fig. 13)
-. Legs and inferior parts at least partly yellow or reddish. If legs completely black, then pronotal pattern differently arranged.. ................................................................................................... 5
5. Dorsal pattern reddish with longitudinal yellow stripes, no hints of darker (blackish or black) patches except for humeral callus. Pronotal punctures robust, well impressed even on central part of disc............................ M. albivittis (Fig. 3)
-. Dorsal pattern partly black or blackish or dark brownish...................................................... 6
6. Dorsal pattern yellow or ochraceous with longitudinal dark stripes definitely black, without reddish tints. Vertex mostly black ................................................................................................... 7
-. Dorsal pattern yellow or ochraceous with longitudinal dark stripes mostly black or brownish with some reddish tints or patches in particular on pronotum. Vertex never black............................................................... 9
7. Pronotum mostly black with narrow median stripe and lateral margins yellow. Head black with yellow patch between upper part of eyes. Legs and ventral parts black, only sides of abdominal ventrites yellow.... M. hamifer (chromatic form b) (Fig. 9 c–d)
-. Pronotum mostly yellow with two longitudinal black stripes on disc. Head mostly yellow. Legs and ventral part yellow or reddish................................................................................................ 8
8. Antennae and antennomeres normally developed, behind perceptibly overcoming humeral calli. Outline more cylindrical. Elytral punctation sparser and more regularly arranged in middle of disc........................... M. bivitticollis (Fig. 5)
-. Antennae short, not reaching the humeral calli when directed backwards. Apical antennomeres remarkably stocky. Outline more elliptical. Elytral punctation denser and irregularly arranged in middle of disc................... M. viator (Fig. 17)
9. Pronotum reddish with a slender longitudinal yellow stripe along midline, lateral margins equally yellow and six black spots transversally arranged (1-4-1)............................................................ M. agonista (Fig. 2)
-. Pronotum yellow with two longitudinal stripes which are black or pitchy anteriorly and posteriorly partly reddish........ 10
10. Interocular distance in male lower (11.5% of BL). Head surface rather shiny with sparser and more impressed punctation. Antennae longer. In male first tarsomere of hind legs longer (about 50% of total length of tarsi). Median lobe of aedeagus enlarged towards apex (Fig. 6 c–d)............................................................... M. chamorroi (Fig.6).
-. Interocular distance in male larger (16.0% of BL). Head surface opaque with denser and finer punctation. Antennae shorter. In male first tarsomere of hind legs shorter (about 40% of total length of tarsi). Median lobe of aedeagus tapered towards apex (Fig. 14 c–d)........................................................................ M. praetorius (Fig. 14)
11. Pronotal yellow pattern includes a V-shaped or bilobed yellow spot close to posterior margin just in front of scutellum (Figs 1; 4; 11; 12)........................................................................................... 12
-. Pronotal yellow pattern always lacking a V-shaped or bilobed yellow spot close to posterior margin just in front of scutellum .................................................................................................. 15
12. Elytral yellow pattern on disc consisting of four distinct spots, lined up along suture, generally not coalescing, 1, 2, 4 rounded, 3 (postmedian) distinctly transverse...................................................................... 13
-. Elytral yellow pattern on disc consisting of four spots, lined up along suture but spots 3–4 (postmedian and apical) externally coalescing giving rise to a fishhook-shaped single patch...................................................... 14
13. Elytral spot 3 (postmedian) elliptical. Head black with yellow clypeus and yellow transverse patch along upper ocular rim. Pronotal yellow patch along lateral margin often C-shaped, being more salient along posterior margin. Pronotum somehow more vaulted with no evidence of posterolateral impressions..................................... M. octoguttatus (Fig. 12)
-. Elytral spot 3 (postmedian) winding. Head black with a trilobate yellow patch in middle. Pronotal yellow patch along lateral margin less salient, often L-shaped. Pronotum somehow more flattened with shallow but perceivable posterolateral impressions............................................................................. M. madefactus (Fig. 11)
14. More slender and smaller on average (3.4–3.8 mm in male). Pronotal yellow patch along lateral margin often L-shaped being less salient along posterior margin. Dorsal punctation (in particular on pronotum) more impressed and robust............................................................................................... M. albopictus (Fig. 4)
-. Stouter and larger (4.2 mm in male). Pronotal yellow patch along lateral margin C-shaped, being more salient along posterior margin. Dorsal punctation (in particular on pronotum) rather fine and sparse........................ M. abditus (Fig. 1)
15. Overall outline stouter and more flattened. Pronotal length/width ratio lower (0.6). Elytral yellow spots generally more transverse and larger. Elytral spot 3 (postmedian) often reaching or very close to lateral margin, with little tendency to coalesce with 4 (apical) spot. Pronotal longitudinal median stripe larger.................................................... 16
-. Overall outline more slender and more cylindrical. Pronotal length/width ratio higher (0.7). Elytral yellow spots generally less transverse and larger. Elytral spot 3 (postmedian) generally not extending close to lateral margin, often with tendency to coalesce with 4 (apical) spot giving rise to a fishhook-shaped single patch (see option 17 below). Pronotal longitudinal median stripe more slender, sometimes linear.................................................................... 17
16. Legs totally black...................................................................... M. luniger (Fig. 10)
-. Femora and basal half of tibiae yellow.................................................... M. crassicollis (Fig. 7)
17. Elytral yellow pattern on disc consisting of four distinct spots, lined up along suture, never coalescing. Sometimes some of such spots missing......................................................................... M. dicaprioi (Fig. 8)
-. Elytral yellow pattern on disc consisting of four spots, lined up along suture but spots 3–4 coalescing, resulting in a fishhookshaped single patch (chromatic form a Fig. 9 a–b). Variable species, sometimes elytral yellow pattern coalescing longitudinally giving rise to a chessboard-like pattern (chromatic form c, Fig. 9e). See option 7 for a third color pattern variation (chromatic form b, Fig. 9 c–d)....................................................................... M. hamifer (Fig. 9)
description: Published as part of Sassi, Davide, 2019, Revision of the Metallactus hamifer species-group (Coleoptera: Chrysomelidae: Cryptocephalinae), pp. 201-245 in Zootaxa 4657 (2) on pages 206-207, DOI: 10.11646/zootaxa.4657.2.1, http://zenodo.org/record/3763876