Metallactus kollari (Perty, 1832)

Sassi, Davide, 2018, Revision of the Metallactus kollari species-group with a new diagnosis of the genus (Coleoptera: Chrysomelidae: Cryptocephalinae), Zootaxa 4413 (1), pp. 57-110 : 65-67

Key to the M. kollari species-group

1. Dark pattern on pronotum reaching posterior margin, so that pronotum is black along all the posterior edge with the exception of lateral angles. However, a small yellow area can be present in front of the scutellum.............................. 2

-. Pronotal posterior margin completely or almost completely yellow.............................................. 4

2. Smaller, length 4.7–5.4 mm. Dorsal outline rather flattened. Pronotal outline transverse and fairly elliptical, with lateral margins regularly rounded and rather large. Elytral dorsal pattern arranged in a large apical subsquared spot, a smaller subrounded black spot can be present on periscutellar area. Aedeagal ventral outline almost straight, hairy dents indistinct. Apex of sclerite III not protruding out of ostium............................................................ M. spilotus ( Fig. 8 )

-. Larger, length 5.3–7.7 mm. Dorsal outline cylindrical. Pronotal outline less transverse, with lateral margins almost straight and narrow. Elytral dorsal pattern arranged in three transverse stripes, sometimes reduced or obliterated, elytral apex always yellow.................................................................................................... 3

3. Black pronotal pattern more extensively black even in the middle, pronotal black pattern anteriorly restricted by a squared yellow patch. Aedeagal ventral outline rather convex in lateral view, hairy dents well impressed. Apex of sclerite III strongly protruding out of ostium..................................................................... M. kollari ( Fig. 3 )

-. Black pronotal pattern formed by two oblique distinct spots, reaching apart posterior margin so that the latter is yellow in the middle. Aedeagal ventral outline almost straight in lateral view, hairy dents less weakly delimited. Apex of sclerite III not protruding out of ostium................................................................ M. londonpridei ( Fig.16 )

4. Legs completely black................................................................................. 5

-. Legs at least partly yellow.............................................................................. 10

5. Pronotum with two feeble but distinct impression in the middle, on sides of median line. Dorsal color pattern mostly yellow, usually with small rounded spots, 2 in the middle of pronotum and 2+2+2(1) ( Fig. 7a ) on elytra. Dorsal black pattern sometimes reduced or spots somewhat larger. Scutellum always black................................ M. languidus ( Fig. 7 )

-. Pronotum without such impression on sides of median line. Scutellum yellow or black............................... 6 on inner part of basal half............................................................... M. bellatrix ( Fig. 14 ) -. Dorsal black pattern generally more extended, on elytra forming a series of three transversal bands. Lateral margin of pronotum narrow, so that not entirely visible from above. Dorsal punctation rather shallow and sparse, in particular on central part of disc. Elytral punctation at least partly arranged in easily distinguishable striae on inner part of basal half................. 7

7. Lateral margin of pronotum slightly angulate in the middle. Elytral transversal black bands fused together along suture, so that the latter is bordered by a quite large black stripe from scutellum to posterior transversal band. Yellow elytral pattern comprises a characteristic anterior rounded spot just behind the periscutellar area. Scutellum strongly raised, stocky, squared, mostly yellow.................................................................................. M. albifrons ( Fig. 5 )

-. Lateral margin of pronotum regularly curved along their entire length. At least the elytral black posterior patch non fused with the median one but forming two subrounded spots not reaching the suture. Suture never largely blackish, only narrowly darkened along its innermost rim. Scutellum normally raised, more slender, completely black............................. 8

8. Smaller, length 4.5 mm (male). Anterior elytral black band reaching the anterior margin so that the latter is almost completely black with the exception of lateral angles. Body outline almost parallel-sided. Pronotal lateral margins regularly curved. A large subrectangular black pattern on pronotal disc............................................ M. regalini ( Fig. 17 )

-. Larger, length 5.4–7.2 mm. Anterior elytral margin totally yellow. Body outline slightly tapered backwards. Pronotal lateral margins almost straight and converging anteriorly. Pronotal black pattern split in two oblique spots not reaching the median line, sometimes a small elliptical black spot just in front the scutellum............................................ 9

9. Pronotal black spots reaching posterior margin, which is consequently partly black on sides of median line. An additional black small rounded spot on pronotal disc, just in front of scutellum. Antennomeres in male of regular shape. Aedeagus tube-shaped, as usual in the species-group. Spermathecal duct longer, with looser coils and a longer non-spiralized and more robust distal section.......................................................................... M. londonpridei ( Fig. 16 )

-. Pronotal black spots never reaching posterior margin, which is consequently completely yellow. Additional small rounded spot in front of scutellum generally missing or in form of a barely perceptible brownish touch. Antennomeres in male particularly lengthened. Aedeagus shape peculiar, with two large and deep pits on ventral surface separated by a sharp carina. Spermathecal duct shorter, with thicker coils and a constant cross section along the length................... M. longicornis ( Fig. 15 )

10. Fore tibiae totally black, median and hind tarsi and tibiae often completely black as well. Black elytral pattern never reaching anterior margin in periscutellar area. Abdominal ventrites totally yellow. A large triangular black patch in the middle of metathorax. Pronotal outline elliptical, transverse, rather flat. Two feeble but distinct impressions in the middle of pronotal disc, on sides of median line................................................................ M. affinis ( Fig. 9 )

-. All tibiae at least partly yellow. Abdominal ventrites usually partly or totally black, if ventrites completely yellow then tibiae and femora totally yellow as well. Pronotal outline fairly vaulted. Without impressions in the middle of pronotal disk, on sides of median line....................................................................................... 11

11. Ventrites, femora and tibiae completely yellow. Rest of inner part and forehead (with the exception of vertex) often totally yellow as well. Ventral surface of aedeagal tube with two weak oblique bulges near basal foramen........ M. guarani ( Fig. 19 )

-. Ventrites, femora and tibiae never completely yellow. Rest of inner part and forehead more extensively black. Ventral surface of aedeagal tube without bulges near basal foramen.......................................................... 12

12. Elytral black pattern in form of two unbroken subrectangular stripes and a pair of small apical spots. Anterior stripe reaching anterior elytral margin so that this latter is completely black................................................... 13

-. Elytral black pattern more or less extended but, when forming transversal stripes, the anterior one never reaching anterior elytral margin so that this latter is completely yellow........................................................... 14

13. Smaller, length 4.4 mm (male). Apex of fore tibiae darkened, fore femora totally yellow. Aedeagal apex short, fairly broadened..................................................................................... M. bezoar ( Fig. 18 )

-. Larger, length 4.7–6.2 mm. Dark color on fore tibiae generally more extended, fore femora partly black. Aedeagal apex more lengthened, narrower......................................................... M. corruptus (dark form) ( Fig. 6 )

14. Elytral black pattern formed by 2+2+1 ( Fig. 11a ) well marked rounded spot, with no tendency to coalesce transversally. Sometimes spots reduced or totally obliterated. Pronotal sides straight and narrow, giving pronotum a slightly subconical outline. Pronotal black pattern in form of two well separated spots, rounded or obliquely arranged, with no tendency to coalesce transversally. Elytral punctures small, shallow, rather dense. Femora and tibiae mostly yellow, sometimes with scattered darker patches.......................................................................... M. dodecastictus ( Fig. 11 )

-. Elytral black pattern formed by transversal stripes or pairs of spots more irregularly delimited, generally with tendency to coalesce transversally; if black pattern formed by 2+2+1(2) (e.g., Fig. 11a ) rounded spots then pronotal black pattern is differently arranged than above. Sometimes black elytral pattern reduced or totally obliterated. Pronotal sides generally more curved. Pronotal black pattern often coalescent over median line. Elytral punctures generally sparser, arranged in more apparent striae. Femora and tibiae generally more extensively black................................................. 15

15. Pronotal black pattern in form of a M-shaped transversal stripe, often notched by a narrow yellow line in the middle. Male antennomeres fairly lengthened (last antennomere/ocular distance ratio equal to about 0.93–1.0). Elytral black pattern arranged in 2+2+2 irregularly shaped spots, with tendency to coalesce transversally but rarely forming complete transverse stripes. Pronotal outline rather lengthened............................................................ M. pollens ( Fig. 12 )

-. Pronotal black pattern forming two separate spots or an unbroken stripe rather transverse, short and hardly similar to a true M. Male antennomeres often normally shaped (last antennomere/ocular distance ratio equal to about 0.6–0.85), if antennomeres fairly lengthened (same ratio equal to about 0.93–1.0) then pronotal black pattern forming three distinct spots on each side. Elytral black pattern often forming distinct transverse stripes. Pronotal outline rather lengthened or more transverse...... 16 lengthened. Elytral black pattern shaped in 2+2+2 with no tendency to coalesce transversally...... M. patagonicus ( Fig. 10 ) -. Pronotal black pattern never split into three distinct spots on each sides. Male antennomeres normally shaped (last antennomere/ocular distance ratio equal to about 0.6–0.85). Pronotal outline rather lengthened or more transversally arranged. Elytral black pattern shaped in 2+2+2 with a fair tendency to coalesce transversally...................................... 17

17. Pronotal outline rather lengthened. Pronotal black pattern forming two separate rather longitudinally arranged winding spots. A third small black spot just on mid line in front of scutellum. Aedeagal apex with sinuate sides and fairly distinct from aedeagal tube............................................................................. M. rileyi ( Figs 2 ; 13 )

-. Pronotal outline more transverse. Pronotal black pattern more transversely arranged, forming an unbroken stripe or two/four separate spots never arranged longitudinally. Aedeagal apex with rather straight convergent sides, barely distinct from aedeagal tube. Sometimes dorsal black pattern reduced or completely obliterated....................................... 18

18. Smaller, length 4.7–6.2 mm. Extremely variable in dorsal color pattern. Elytral pattern often in 2+2+2, but spots can coalesce transversally to form three unbroken stripes, or can be totally obliterated. Median lobe of aedeagus often lighter in colour, not thickened on sides of apex. Branches of sclerite IV of endophallus slightly shorter than sclerite III in the folded up structure, with blunt rounded apex................................................................ M. corruptus ( Fig. 6 )

-. Larger, length 5.5–7.8 mm. Extremely variable in dorsal color patter. Elytral pattern often in 2+2+2, but spots can coalesce transversally to form three unbroken stripes, or can be totally obliterated. Median lobe of aedeagus generally darker in colour, often slightly thickened on sides of apex. Branches of sclerite IV of endophallus slightly longer than sclerite III in the folded up structure, concave (= saddled) at apex...................................................... M. albipes ( Figs 1 ; 4 )

Figures

FIGURE 19. M. guarani. a–b: habitus; c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [0.9 mm]; f: sclerites II–III–IV of endophallus [0.7 mm]; g: sclerite I and dorsal spicule of endophallus [0.7 mm]; h: spermatheca [1.1 mm]; k–m: rectal apparatus in dorsal (k) and ventral (m) view [0.9 mm]. a–b: holotype. vb: ventral bulges. Square brackets: length of scale segment.

FIGURES 7–8. M. languidus (7), M. spilotus (8). 7a–b: habitus; 7c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [1.0 mm]; 7f: sclerites II–III–IV of endophallus [0.8 mm]; 7g: sclerite I and dorsal spicule of endophallus [0.8 mm]; 7h: spermatheca [1.0 mm]; 7k–m: rectal apparatus in dorsal (k) and ventral (m) view [1.0 mm]. 8a–b: habitus; 8c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [1.1 mm]; 8f: sclerites II–III–IV of endophallus [0.7 mm]; 8g: sclerite I and dorsal spicule of endophallus [0.7 mm]; 8h: spermatheca [0.8 mm]; 8k–m: rectal apparatus in dorsal (k) and ventral (m) view [1.0 mm]. 7a–b: lectotype; 8a–b: holotype. Square brackets: length of scale segment.

FIGURES 3–4. M. kollari (3), M. albipes (4). 3a–b: habitus; 3c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [1.4 mm]; 3f: sclerites II–III–IV of endophallus [1.2 mm]; 3g: sclerite I and dorsal spicule of endophallus [0.8 mm]; 3h: spermatheca [0.9 mm]; 3k–m: rectal apparatus in dorsal (k) and ventral (m) view [1.3 mm]. 4a–b/a1: habitus; 4c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [1.1 mm]; 4f: sclerites II–III–IV of endophallus [0.8 mm]; 4f1: same of 4f in ventral view; 4g: sclerite I and dorsal spicule of endophallus [0.3 mm]; 4h: spermatheca [1.2 mm]; 4k–m: rectal apparatus in dorsal (k) and ventral (m) view [1.3 mm]. 3a–b: lectotype; 4a–b: lectotype. 4a1 paralectotype of M. nigrofasciatus n. syn. hd: hairy dent: scI–IV: sclerites I–IV of endophallus; ds: dorsal spicule; lt: lateral thickenings. Square brackets: length of scale segment.

FIGURES 15–16. M. longicornis (15), M. londonpridei (16). 15a–b/a1: habitus; 15c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [1.2 mm]; 15f: sclerites II–III–IV of endophallus [0.6 mm]; 15g: sclerite I and dorsal spicule of endophallus [0.6 mm]; 15h: spermatheca [0.9 mm]; 15k–m: rectal apparatus in dorsal (k) and ventral (m) view [1.4 mm]; 15n: antenna [2.2 mm]. 16a–b: habitus; 16c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [0.9 mm]; 16f: sclerites II–III–IV of endophallus [0.6 mm]; 16g: sclerite I and dorsal spicule of endophallus [0.8 mm]; 16h: spermatheca [0.9 mm]; 16k–m: rectal apparatus in dorsal (k) and ventral (m) view [1.3 mm]. 15a–b: holotype; 15a1: paratype from Cuyaba, Mato Grosso, Brazil); 16a–b: holotype. Square brackets: length of scale segment.

FIGURES 13–14. M. rileyi (13), M. bellatrix (14). 13a–b: habitus; 13c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [1.0 mm]; 13f: sclerites II–III–IV of endophallus [0.6 mm]; 13g: sclerite I and dorsal spicule of endophallus [0.9 mm]; 13h: spermatheca [0.8 mm]; 13k–m: rectal apparatus in dorsal (k) and ventral (m) view [0.9 mm]; 13n: antenna [1.5 mm]. 14a–b: habitus; 14h: spermatheca [0.7 mm]; 14k–m: rectal apparatus in dorsal (k) and ventral (m) view [0.9 mm]. 13a–b: holotype; 14a–b: holotype. Square brackets: length of scale segment.

FIGURES 5–6. M. albifrons (5), M. corruptus (6). 5a–b: habitus; 5c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [1.1 mm]; 5f: sclerites II–III–IV of endophallus [0.6 mm]; 5g: sclerite I and dorsal spicule of endophallus [0.6 mm]; 5h: spermatheca [1.2 mm]; 5k–m: rectal apparatus in dorsal (k) and ventral (m) view [1.3 mm]. 6a–b: habitus; 6c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [1.0 mm]; 6f: sclerites II–III–IV of endophallus [0.8 mm]; 6g: sclerite I and dorsal spicule of endophallus [1.0 mm]; 6h: spermatheca [1.0 mm]; 6k–m: rectal apparatus in dorsal (k) and ventral (m) view [0.9 mm]. 5a–b: specimen from Cuyaba (Mato Grosso, Brazil); 6a–b: lectotype. hd: hairy dent: scI–IV: sclerites I–IV of endophallus; ds: dorsal spicule. Square brackets: length of scale segment.

FIGURES 17–18. M. regalini (17), M. bezoar (18). 17a–b: habitus; 17c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [0.8 mm]; 17f: sclerites II–III–IV of endophallus [0.5 mm]; 17g: sclerite I and dorsal spicule of endophallus [0.4 mm]. 18a–b: habitus; 18c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [0.8 mm]; 18f: sclerites II–III–IV of endophallus [0.6 mm]; 18g: sclerite I and dorsal spicule of endophallus [0.5 mm]. 17a–b: holotype; 18a–b: holotype. hd: hairy dent: scI–IV: sclerites I–IV of endophallus; ds: dorsal spicule. Square brackets: length of scale segment.

FIGURES 9–10. M. affinis (9), M. patagonicus (10). 9a–b: habitus; 9c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [0.8 mm]; 9f: sclerites II–III–IV of endophallus [0.4 mm]; 9g: sclerite I and dorsal spicule of endophallus [0.7 mm]; 9h: spermatheca [1.2 mm]; 9k–m: rectal apparatus in dorsal (k) and ventral (m) view [1.2 mm]. 10a–b: habitus; 10c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [1.0 mm]; 10f: sclerites II–III–IV of endophallus [0.5 mm]; 10g: sclerite I and dorsal spicule of endophallus [0.9 mm]; 10h: spermatheca [1.1 mm]; 10k–m: rectal apparatus in dorsal (k) and ventral (m) view [1.1 mm]. 9a–b: lectotype; 10a–b: lectotype. Square brackets: length of scale segment.

FIGURES 11–12. M. dodecastictus (11), M. pollens (12). 11a–b: habitus; 11h: spermatheca [1.1 mm]; 11k–m: rectal apparatus in dorsal (k) and ventral (m) view [1.1 mm]. 12a–b: habitus; 12c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [1.1 mm]; 12f: sclerites II–III–IV of endophallus [0.7 mm]; 12g: sclerite I and dorsal spicule of endophallus [0.9 mm]; 12h: spermatheca [1.1 mm]; 12k–m: rectal apparatus in dorsal (k) and ventral (m) view [1.3 mm]; 11n: antenna [2.2 mm]. 11a–b: lectotype; 12a–b: lectotype. Square brackets: length of scale segment.

FIGURES 1–2. median lobe of aedeagus with everted endophallus. M. albipes (1), M. rileyi (2). a: dorsal view; b: lateral view. scI–IV: sclerites I–IV of endophallus; ds: dorsal spicule. Length of scale segment: 1.6 mm.