Metallactus albopictus Suffrian, 1866

Sassi, Davide, 2019, Revision of the Metallactus hamifer species-group (Coleoptera: Chrysomelidae: Cryptocephalinae), Zootaxa 4657 (2), pp. 201-245 : 212-215

Metallactus albopictus Suffrian, 1866

( Figs 4 ; 21 )

Metallactus albopictus Suffrian, 1866: 331 ; Clavareau, 1913: 92 (catalogue); Blackwelder, 1946: 641 (catalogue); Agrain et al., 2017: 59 (annotated checklist).

Griburius persimilis Burmeister, 1877: 66 ; Clavareau, 1913: 91; Blackwelder, 1946: 640; Agrain et al., 2017: 57. syn. nov.

Types. Suffrian did not mention the number of specimens under study but he reported two type depositories (coll. Deyrolle and MNHUB) and, for the material housed in MNHUB, the name of single collector (Sellow) and a single locality (“Collo del Sagramento”). In MNHUB two syntypes have been tracked down. The label information matches the registration data from the old catalogue of the MNHUB (“23968 Metallactus albopictus Suffr. * 1. Còlon. d. Sàcrament., Sello”). Besides, a further syntype was tracked down in BMNH, where part of Deyrolle's material was incorporated. The typification has been made as follows, in order to stabilize the epithet. LECTOTYPE (by present designation): ♂, glued, aedeagus glued on the same card bearing the specimen, abdomen glued on a separate card // “23968” [white label, printed] // “ albopictus (Bug.) Suffr. * Còl. del Sàcr. Sell” [blue label, handwritten] // “ Metallactus albopictus Suffrian, 1866 LECTOTYPUS D. Sassi des.” [red label, printed] // (MNHUB). PARALECTOTYPE: 1♀, pinned // “Type Suffr coll Deyrolle” [white label, handwritten] // “ Metallactus albopictus Suffr Brazil ” [white label, handwritten] // “Baly coll.” [white label, printed] // “ Metallactus albopictus Suffrian, 1866 PARALECTOTYPUS D. Sassi des.” [red label, printed] // (BMNH).

Thanks to the courtesy of Arturo Roig Alsina (MACN) I had the opportunity of examining high resolution photographs of a syntype of Griburius persimilis Burmeister, 1877 . It is a male that corresponds well to the original description. For this reason, it is here designated as the lectotype of the species, in order to stabilize the epithet. LEC- TOTYPE (by present designation): ♂, pinned // “ Griburius persimilis Burmeister 1877 Typus” [red label, handwritten] // “Bnen Aires” [sic] [green label, printed] // “ Griburius persimilis Burmeister, 1877 LECTOTYPUS D. Sassi des.” [red label, printed] // “ Metallactus albopictus Suffrian, D. Sassi det. 2019” [red label, printed] // (MACN).

However, a careful comparison with the available material of M. albopictus allows me to state that the specimen undoubtedly falls within the range of variability of the latter species. Therefore, the following synonymy is proposed: Metallactus albopictus Suffrian, 1866 = Griburius persimilis ( Burmeister, 1877) syn. nov.

Type localities. Metallactus albopictus . Colonia del Sacramento (Colonia, Uruguay). Suffrian’s indications regarding the localities of the type series are rather generic. He seems to consider “Còl. del Sàcr.” to be a Brazilian toponym. However , no evidence has been found regarding the existence of a place with a similar name in southern Brazil. On the other hand, the name corresponds to a well-known Uruguayan locality. Hence, I am inclined to deem that the lectotype comes from Uruguay, where the collector, F. Sello, travelled a lot ( Krausch, 2002).

Griburius persimilis . “ Buenos Aires ” ( Argentina).

Further material examined. ARGENTINA: B. A. Tigre 28.IX.1969 C. W. & L. B. O’ Brien (1, BYU) ; Tigre 12 Oct. 1941 (2, BMNH) ; Buenos Aires, delta Paranà Carapachay Oct. 1940 coll. Monrós (2, USNMNH) ; Buenos Aires Ing ° Maswich Nov. 1941 coll. Monrós (3, USNMNH) ; Buenos Aires, 23 Nov. 1938 Carl J. Drake (1, USNMNH) ; Buenos Aires coll. Dr. Reitter (1, NHMB) ; Buenos Aires San Fernando XII.1954 & XII.955 coll. Daguerre (6, USNMNH) ; La Plata Balzan 188[...] (3, MSNG) ; Buenos Aires Dique Lujan XI.941 coll. Monrós (4, USNMNH) ; Haedo Jan. 1926 coll. G. R. Harrington (1, USNMNH) ; Dolores ST 228 28.3. 27 in orchard (1, USNMNH) ; El Jabali 29.XII.1930 J. B. Anderson (2, BMNH) ; NW Patagonia 1,000-3,000ft dec 1919 (1, BMNH) . BRAZIL: R.[io]G.[rande do] S.[ul] Pelotas 5.XI.61 (1, BMNH) . URUGUAY: Colonia Piedra de los Indios ca Ruta 21 km 184.5 20.XI.2010 G. J. Wibmer (3, BYU) .

Distribution. Argentina, Brazil, Uruguay. New for Uruguay.

Diagnosis. A Metallactus of small size belonging to a subgroup of species characterized by a V-shaped yellow spot on pronotum just in front of scutellum. The subgroup also comprises M. abditus , M. octoguttatus , M. madefactus . However, in M. albopictus the pronotal lateral yellow stripe is not so salient along the posterior margin like in M. abditus and in M. octoguttatus , so that recalling an upside-down L rather than a C as in the two latter species. Elytral apical yellow spot is differently shaped in M. madefactus ( Fig. 11 a-b). Furthermore, dorsal punctation is perceptibly stronger compared to the closest species mentioned before.

Description of male. Habitus in Fig. 4 a–b (LT). BL = 3.4–3.8 mm, BW = 2.0– 2.1 mm, PL = 1.2–1.3 mm, PW = 1.8–1.9 mm. Interocular distance 11.8–13.2% of BL.

Head black, with two sickle-shaped yellow spots on lower part of vertex, almost in conctact along median line. Labrum yellowish. Vertex quite dull, with few punctures scattered throughout its surface, sometimes combined with fine whitish setae. Frontoclypeal area with quite coarse punctation and sparse pale setae above all along lower part of inner ocular margin and below the antennal insertion. Mid-cranial suture short, slightly impressed so that surrounding surface almost flat. Antennae black, with antennomeres 1-5 partly brownish.

Pronotum black with lateral margin and outer part of anterior margin covered with a single upside down Lshaped spot; a median bilobed yellow spot close to posterior margin just in front to scutellum; a smaller almost linear or narrowly ellyptical median one, yellow as well, extended from anterior margin to the center of disc. Pronotal shape elliptical with lateral margins thin, barely visible from above, regularly curved so that maximum width roughly at half length. Posterolateral impressions obliterated. Surface moderately lustrous with scattered, distinctly impressed punctation, slightly sparser and shallower on disc.

Scutellum completely black, raised, sub-squared with truncated apex, almost bald to distinctly covered with yellowish setae, impunctate with tiny and sparse micropunctation.

Elytron black with yellow pattern consisting of two spots along the suture, first one, elliptical, beside scutellum, the second, generally transverse and often reaching lateral margin, at middle; a third hooked spot on apical clivus, concave toward median line, generally reaching apex and suture. A further marginal yellow spot along anterior third of lateral margin, extended on outer part of anterior margin and epipleuron. Sometimes posterior end of this spot fused with the median transverse one. Elytral outline parallel-sided and very weakly flattened on disc. Postscutellar area not raised. Humeral callus moderately prominent, impunctate. Surface scarcely lustrous with punctation rather deeply impressed, arranged in almost regular rows, reduced and shallower on apical clivus. Punctures more confusedly arranged in anterior inner part of disc. Intervals flat. Epipleural surface slightly convex, smooth, devoid of punctation.

Pygidium brownish with sides partly lighter at middle, sometimes paler pattern forming a blurred transverse stripe; surface smooth, matt, with indistinct sparse punctures and whitish setae.

Inferior parts of thorax completely black. Prothorax (prosternal process and hypomera) rather coarsely punctured. Prosternal process with long setae, hypomera almost bald. Meso- and metathorax rather shallowly punctured, with sparse, whitish setae. Abdominal ventrites indistinctly punctured, rather densely covered with whitish setae, with large yellow border. Legs totally black.

Fifth abdominal ventrite with a deep, parallel-sided, smooth, bald, impunctate median depression and not notched posterior margin. Median lobe of aedeagus ( Fig. 4 c-e) cylindrical with well differentiated triangular, short, blunt triangular apex, delimited by curved sides, clearly bent ventrally. Hairy dents perceptibly sticking out, well impressed, starkly delimited, bearing long, straight setae. In ventral view median lobe raised in a median, short, squat carina distinctly tapered towards aedeagal base. Ventral profile markedly and angularly swollen in lateral view. Endophallus ( Fig. 4 f–g) with sclerite I strongly developed and pigmented, denticle apparent, straight, slightly sticking out laterally. Dorsal spicule well developed, thorn-like. Sclerite II well developed, long, slender, tapered, distinctly bent at base. Arch of sclerite III short, rather squat. Apex of sclerite III straight, moderately lengthened, pointed, not expanded on its proximal half. Branches of sclerite IV slightly shorter than sclerite III in the folded-up structure, straight, almost parallel-sided, with rounded, slightly asymmetrical, microdenticulate apex and surface fairly sculptured, covered with small wrinkles.

Female. BL = 4.5–4.7 mm, BW = 2.5–2.6 mm, PL = 1.4–1.5 mm, PW = 2.3 mm. Interocular distance 14.9– 15.6% of BL. Female differs in stouter body, greater interocular distance and shorter antennae.

Fifth abdominal ventrite in females with rather deep, rounded pit, with bottom dull, impunctate, covered with tiny wrinkles. Vasculum of spermatheca ( Fig. 4h ) relatively robust, scarcely pigmented, with proximal branch slightly twisted to almost straight. Distal branch very long, tapered in long, pointed, curved apex. Ampulla weakly pigmented, small, slightly shifted on dorsal side of vasculum. Duct insertion and sperm gland insertion perceptibly distinct. Duct uniform in size, slender, coiled with coils rather thick and regularly arranged. Distal not coiled portion of duct short, almost straight to absent. Insertion on bursa copulatrix large, swollen, clearly pigmented.

Figures

FIGURES 3–4. M. albivittis (3), M. albopictus (4). 3a–b: habitus; 3c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [0.7 mm]; 3f: antenna [2.1 mm]; 3g: spermatheca [0.5 mm]. 4a–b: habitus; 4c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [0.7 mm]; 4f: sclerite I and dorsal spicule of endophallus [0.5 mm]; 4g sclerites II–III–IV of endophallus [0.5 mm]; 4h: spermatheca [0.5 mm]; 4k: antenna [1.5 mm]. 3a–b: holotype; 4a–b: lectotype. hd: hairy dent; scI–IV: sclerites I–IV of endophallus; ds: dorsal spicule. Square brackets: length of scale segment.

FIGURES 18–26. Distribution maps for Metallactus hamifer species-group. M. abditus (18); M. agonista (19); M. albivittis (20); M. albopictus (21); M. bivitticollis (22); M. chamorroi (23); M. crassicollis (24); M. dicaprioi (25); M. hamifer (26). Grey squares: localities reported in a generic way.

FIGURES 10–11. M. luniger (10), M. madefactus (11). 10a–b: habitus; 10c–e: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [0.9 mm]; 10f: sclerite I and dorsal spicule of endophallus [0.6 mm]; 10g: sclerites II–III–IV of endophallus [0.5 mm]; 10h: spermatheca [0.6 mm]; 10k: antenna [2.0 mm]. 11a–b: habitus; 11c: spermatheca [0.4 mm]; 11d: antenna [1.9 mm]. 10a–b: paralectotype (BMNH); 11a–b: paratype (DSPC). scI–IV: sclerites I–IV of endophallus; ds: dorsal spicule. Square brackets: length of scale segment.