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

description: Metallactus pollinctor Suffrian, 1866
(Figs 13; 30)
Metallactus pollinctor Suffrian, 1866: 348; Clavareau, 1913: 93 (catalogue); Blackwelder, 1946: 641 (catalogue).
Types. In the original description Suffrian did not mention the number of the studied specimens but he reported two type depositories: Baly collection (now incorporated in BMNH) and MNHUB. For the material housed in the latter, he quoted a single collector (Sellow) and a single locality (“Caasapava” [sic]). At present, one single syntype is housed in the collections of BMNH. Four syntypes are present in MNHUB, it is almost certain that they all belong to the same series, even though only one specimen is labelled. The number of specimens and the label information match the registration data from the old catalogue of the MNHUB (“23959 pollinctor Suffr. 4 [specs.], Cassapava, Sello”). The type designation was 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 // “pol- linctor Suffr* Cassapava Sello” [blue label, handwritten] // “23959” [white label, handwritten] // “ Metallactus pollinctor Suffrian, 1866 LECTOTYPUS D. Sassi des.” [red label, printed] // (MNHUB). PARALECTOTYPES: 1♂ 2♀ [none of them bear any label, but they certainly belong to the same series of the lectotype] // (MNHUB); 1♂, glued, aedeagus and detached abdomen glued on the same card bearing the specimen // [blank pale blue label] // [unreadable cipher, white label, handwritten] // “Type Suffr Coll. Baly” [white label, handwritten] // “Baly Coll.” [white label, printed] // “ Metallactus pollinctor Suffr Brazil ” [recto], [verso, unreadable phrase] [white label, handwritten] // (BMNH).All paralectotypes labelled: “ Metallactus pollinctor Suffrian, 1866 PARALECTOTYPUS D. Sassi des.” [red label, printed].
Type locality. Caçapava do Sul (Rio Grande do Sul, Brazil).
Further material examined. ARGENTINA: Buenos Aires Tigre I. 955 & III.955 & XI.955 & XII.955 Daguerre (6, USNMNH); Buenos Aires Tigre Delta XII.962 Daguerre (2, USNMNH); Punte de Zara 3.I.932 Daguerre (1, USNMNH); Buenos Aires XII.[18]98-I.[18] 99 F. Silvestri (1, (MSNG).
Distribution. Argentina, Brazil. New to Argentina.
Diagnosis. A Metallactus of small-medium size. It belongs to the subgroups of species characterized by longitudinal dorsal stripes. Among these species, M. pollinctor can be distinguished by its peculiar pronotal pattern made up of two median trapezoidal spots and two lateral ones, smaller and rounded. Besides, ventral parts (except for outer part of abdominal ventrites) and legs are totally black. In the subgroup only M. hamifer has similar ventral and legs color pattern, but pronotum lacks lateral rounded black spots and looks distinctly less transverse.
Description of male. Habitus in Fig. 13 a–b (LT). BL = 3.9–4.3 mm, BW = 2.4–2.5 mm, PL = 1.4 mm, PW = 2.1–2.3 mm. Interocular distance 10.3–11.6% of BL.
Head black with two yellow eyebrow-shaped spots obliquely arranged, medially coalescent above the upper margin of eyes. Labrum brownish. Vertex quite dull, bare, without true punctures but sparsely micropunctured. Frontoclypeal area rugosely punctured, covered with dense quite long witish setae. Mid-cranial suture short, but generally well impressed so that surrounding surface slightly swollen. First five antennomeres yellowish, sublucid, the subsequent ones totally darkened, dull and more diffusedly setose.
Pronotum yellow with two large trapezoidal to vaguely bilobed black spots not reaching margins nor coalescing along median line; two further small rounded black spots close to lateral margins. Pronotal shape elliptical, with maximum width in the middle. Lateral margins rather thin, regularly arcuate. Posterolateral impression obliterated. Surface rather flat, moderately shiny with scattered well impressed punctation above all on sides.
Scutellum totally black, dull, scarcely raised, apex truncated in a straight line. Bald and devoid of punctures.
Elytron surface black with two narrow, straight, longitudinal yellow stripes extending from anterior margin to apex where they coalesce, first one running along suture, second one on the middle of disc. Epipleuron and anterior half of elytral lateral margin yellow as well. Elytral outline parallel-sided and rather flattened on disc. Postscutellar area not raised. Humeral callus weakly developed, impunctate. Surface moderately matt with shallow, small, irregularly arranged punctation, only in posterior half of disc punctures arranged in rows. Intervals flat.
Pygidium black with yellow transverse stripe in the middle, smooth, covered with sparse shallow punctures and whitish setae.
Inferior parts of thorax totally black, only external part of hypomera partly yellow. Hypomera bare, rather deeply punctured, mesoepimera and mesoepisterna almost bare with scarce shallow punctures. Metaepisterna and metasternum with quite close, shallow punctation and sparse setae. Prosternal process coarsely punctured with long setae. Abdominal ventrites black with large yellow border, shallowly and sparsely punctured, with sparse setae. Legs totally black.
Median depression on fifth abdominal ventrite moderately impressed, impunctate, almost bare. Posterior margin of fifth abdominal ventrite weakly notched. Median lobe of aedeagus (Fig. 13 c–e) cylindrical with apex scarcely separated from the rest of aedeagus, blunt, in lateral view almost straight. Hairy dents moderately impressed, scarcely delimited, bearing rather long, dense setae. Aedeagal ventral surface barely swollen in lateral view, devoid of particular structures. Endophallus (Fig. 13 f–g) with sclerite I strongly developed and pigmented, denticle apparent, rather pointed, bent upwards and not perceptibly sticking out laterally. Dorsal spicule long, thorn-like. Sclerite II long, robust, distinctly bent at base and gradually tapered towards apex. Arch of sclerite III slender, raised. Apex of sclerite III straight, slender and pointed distally, fairly expanded on its proximal half, so that the sclerite looks like the head of a grebe. Branches of sclerite IV shorter than sclerite III in the folded-up structure, slightly arched towards ventral direction, with blunt, almost symmetrical, microdenticulate apex and surface perceptibly rugose.
Female. BL = 5.2–5.3 mm, BW = 3.1 mm, PL = 1.5 mm, PW = 2.7 mm. Interocular distance 11.5–13.2% of BL.
Fifth abdominal ventrite in females with quite large, rather deep, almost circular pit. Bottom of pit bald, matt, impunctate but covered with tiny wrinkles. Vasculum of spermatheca (Fig. 13h) scarcely pigmented with straight proximal branch not swollen at base, long distal branch and very short, pointed, straight apex. Ampulla strongly pigmented, slightly shifted on dorsal side of vasculum. Duct and sperm gland insertions clearly distinct. Duct uniform in size, rather robust, remarkably short, coiled with coils markedly loose and irregularly arranged, more resembling wavings than true coils. Distal not coiled portion of duct long, straight. Insertion on bursa copulatrix lengthened, almost straight, moderately pigmented.
Remarks. In the single syntype housed in BMNH the aedeagal apex is fairly narrower and slighty more pointed than in the studied specimens from Argentina. Taxonomic significance of this difference, if any, needs to be tested on a larger number of specimens.
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 232-234, DOI: 10.11646/zootaxa.4657.2.1, http://zenodo.org/record/3763876