Metallactus hamifer Suffrian, 1866

Sassi, Davide, 2019, Revision of the Metallactus hamifer species-group (Coleoptera: Chrysomelidae: Cryptocephalinae), Zootaxa 4657 (2), pp. 201-245 : 223-226

Metallactus hamifer Suffrian, 1866

( Figs 9 ; 26 )

Metallactus hamifer Suffrian, 1866: 333 ; Clavareau, 1913: 93 (catalogue); Blackwelder, 1946: 641 (catalogue).

Types. Suffrian did not mention the number of specimens under study but he reported the name of single collector (Sellow) and a single type depository (MNHUB). In MNHUB two specimens have been tracked down whose label information matches the registration data from the old catalogue of the MNHUB (“23967 Metallactus hamifer Suffr. * 2. Brasil, v. Olf ”). However, the name of the collector (von Olfers) does not match what reported in the original description (Sellow). As a matter of fact, several type series of the Metallactus hamifer species-group described by Suffrian were collected by Sellow and von Olfers and their names alternate several times in sequence in the MNHUB catalogue and on the specimens labels. For that reason, I am inclined to deem that Suffrian mixed up the two names in the original description of M. hamifer in his monography (1866), and the two specimens housed in MNHUB have to be considered the type series of the species. 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 // “23967” [white label, printed] // “ hamifer Suffr. * Brasil v. Olf. ” [blue label, handwritten] // “Hist.-Coll. ( Coleoptera ) Nr. 23967 Metallactus hamifer Suffr. * Brasil., v. Olfers Zool. Mus. Berlin” [green label, printed] // “ SYNTYPE Metallactus hamifer, Suffrian 1866 labelled by MFNB 2019” [red label, printed] // “ Metallactus hamifer Suffrian, 1866 LECTOTYPUS D. Sassi des.” [red label, printed] // (MNHUB). PARALECTOTYPES: 1♂ // “Hist.-Coll. ( Coleoptera ) Nr. 23967 Metallactus hamifer Suffr. * Brasil., v. Olfers Zool. Mus. Berlin” [green label, printed] // “ SYNTYPE Metallactus hamifer, Suffrian 1866 labelled by MFNB 2019” [red label, printed] // “ Metallactus hamifer Suffrian, 1866 PARALECTOTYPUS D. Sassi des.” [red label, printed] // (MNHUB).

Type locality. Brazil .

Further material examined. ARGENTINA: Buenos Aires coll. Dr. Reitter (2, NHMB) ; Buenos Aires 30.XII.67 GE Bohart (1, BYU) ; Prov . Buenos Aires 1: XI.1949 J. Förster (1, ZSM) ; Buenos Aires 23.XI.1938 Carl J. Drake (1, USNMNH) ; Buenos Aires San Fernando XI.952 & XII.953 & X.954 & XI.954 & XII.954 & I.955 & XI.955 & XII.955 & III.956 & XII.956 & III.957 & IX.957 & X.957 & XI.960 & X.962 & XI.962 Daguerre (54, USNMNH) ; Buenos Aires S. Isidro XI.956 Daguerre (2, USNMNH) ; Buenos Aires Tigre I. 956 Daguerre (1, USNMNH) ; Buenos Aires Rosas F. C. Sud Juan B. Daguerre (4, USNMNH) ; Buenos Aires Ing ° Maswich Nov. & Dic. 1941 & III.1942 coll. Monrós (5, USNMNH) ; Buenos Aires Zelaya XI. 957 Daguerre (2, USNMNH) ; Buenos Aires Dique Lujan XI.938 & 20.XI.962 Daguerre (1, USNMNH) ; Buenos Aires Dique Lujan 27.XI.955 Daguerre (1, USNMNH) ; Buenos Aires Escobar 13.XI.1949 Leg. Wittmer (1, USNMNH) ; Buenos Aires Dique Lujan Nov. 941 Daguerre (3, USNMNH) ; La Pampa XI.944 Daguerre (3, USNMNH) ; Salta Cafayate II.1953 K. J. Hayward (1, USNMNH) ; Salta Cerro San Bernardo 5.I.945 coll. Monrós (1, USNMNH) ; Salta San Bernardo II. 959 (1, USNMNH) ; Salta Oran En. 945 Martinez (2, USNMNH) ; Salta Güemes Feb. 944 Martinez; (1, USNMNH) ; Güemes 8.I.1930 H. A. Jaynes (1, USNMNH) ; Charata Chaco I.1995 & XII.1995 (6, MSNM) ; Estancia la Noria Rio San Javier Santa Fè G. E. Bryant 10.I.1912 (1, BMNH) ; Santiago del Estero (2, MNHN) ; Santiago del Estero Bords du Rio Salado Env. D’Icano E. R. Wagner 1909 (1, MNHN) ; Santiago del Estero Ojo de Agua III.1992 (1, DSPC) ; Villa Castelli y Chilecito leg. H. Förster (2, ZSM) ; Chaco 2 km N Isla del Cerrito 28.I.1989 C. W. & L. O’Brien & G. Wibmer (1, BYU) ; Chaco Resistencia X.1980 (1, DSPC) ; Chaco Resistencia, XI.948 (1, NHMB) ; Resistencia Chaco IX.35 H. C. Hepper (1, DSPC) ; Chaco Resistencia 50km NE Resistencia 25.I.1989 C. W. & L. O’Brien & G. Wibmer (1, USNMNH) ; Cordoba Calamuchita Salsacate Ene.1979 (2, DSPC) ; Cordoba Huerta Grande 1000m 22.X.54 leg. H. Förster (1, ZSM) ; Tucuman Alrededores Ciudad 8.XI.952 & 8.XII.952 (4, USNMNH) ; Tucuman Camino a Bella Vista Arroyo Manantial 16.XI.952 (1, USNMNH) ; Tucuman Bella Vista 25.I.953 Wygodzinsky (1, USNMNH) ; Santa Fe Villa Ana Feb.1926 K. J. Hayward (2, BMNH) ; Santa Fé Las Garzas bordo du Rio Las Garzas Nord du Chaco de Santa Fé (2, NMV); Chaco de Santa Fé Las Garzas bords du Rio Las Garzas 25 km W d’Ocampo E. R. Wagner 1903 (6, NMV & MDPC) ; Entre Ríos Liebig XI.90 (4, DSPC) ; Entre Ríos Hwy. 6 nr. Raíces 14.I.1989 C. W. & L. O’Brien & G. Wibmer (1, BYU) ; Corrientes, 3 km E Corrientes 18.I.1989 C. & L. O’Brien & G. Wibmer (1, USNMNH) ; Corrientes Alvear I.1991 (1, DSPC) ; Formosa Las Lomitas XI.950 Daguerre (1, USNMNH) ; Formosa Gran Guardia XII.951 coll. H. Förster (2, USNMNH) . BOLIVIA: Santa Cruz Santa Cruz 28.IX.72 G. E. Bohart (2, BYU) . BRAZIL: Pelotas Sud Brasilien (1, NMV) . PARAGUAY: Pres. Hayes 42 km NW Benjamín Aceval 31. Jan. 83 E. G. Riley (2, ERPC) ; Dept . San Pedro Estancia Lomas 4.IV.2009 leg. U. Drechsel (1, UDPC) ; Sapucay WTF Foster coll. (1, USNMNH) . URUGUAY: Colonia Dept. Rosario Ibirapita Ranch 20.X.1973 D. H. Habeck (2, FSCA) ; Rocha Ruta 16 km 1-2 15.XI.2011 G. J. Wibmer (2, BYU) ; Colonia Ruta 21 Piedra de los Indios 6.XI.1992 G. J. Wibmer (2, BYU) ; Colonia San Pedro Ruta 21 ca km 186.5 27.XI.2012 G. J. Wibmer (2, BYU) ; Brisas de la Plata 8.XII.43 (2, USNMNH) .

Distribution. Argentina, Bolivia, Brazil, Paraguay, Uruguay. New from Argentina, Bolivia, Paraguay, Uruguay.

Diagnosis. A Metallactus of medium size. Variable species, but always characterized by a longitudinal median yellow stripe on pronotum extended from the anterior to posterior margin, generally of the same width or widened in the rear section. M. dicaprioi looks very similar, but it is well distinguished by the finer dorsal punctation, the more rounded elytral spots, the posterior one divided in two separate marks (shaped like a fishhook in M. hamifer ). M. luniger is similar as well but differs in the stockier outline and in the larger pronotal longitudinal light pattern.

Description of male. Habitus in Fig. 9 a–b (LT). BL = 3.8–4.9 mm, BW = 2.3–2.9 mm, PL = 1.4–1.8 mm, PW = 2.1–2.7 mm. Interocular distance 12.2–13.2% of BL.

Head black, with two triangular to sickle-shaped yellow spots on lower part of vertex, broadly in conctact along median line. Labrum yellowish. Vertex quite dull, with few, scattered punctures and some fine, short, whitish setae. Frontoclypeal area, sighly impressed between eyes, with quite coarse punctation and sparse pale setae mainly along lower part of inner ocular margin and below the antennal insertion. Mid-cranial suture short, clear-cut; surrounding surface almost flat. First five antennomeres brownish, sublucid, the subsequent ones totally darkened, dull, more flattened and more diffusedly setose.

Pronotum black with a C-shaped yellow spot covering lateral margin and the external third of anterior and posterior ones. A median, longitudinal, relatively narrow yellow line, slightly enlarged on its posterior end, extended across the whole disc. Pronotal shape relatively short-elliptical with lateral margins thin, barely visible from above, regularly curved with maximum width slightly behind the middle. Posterolateral impressions obliterated to faintly impressed, so that posteror margin feebly thickened behind them. Surface moderately lustrous with scattered, indistinct to moderately impressed punctation, slightly sparser and shallower on disc.

Scutellum black, dull, distinctly raised, finely setose and minutely punctured. Apex truncated in a straight line.

Elytron surface black with three yellow spots in a line along midline of disc. First spot obliquely arranged just beside scutellum; second one, transverse, at middle; third one, on apical clivus, vaguely fishhook-shaped extending to marginal apex and briefly salient along suture with its slimmer branch. Anterior third of lateral margin yellow as well with light color extending to epipleuron and briefly ascending along outer part of basal margin. Such yellow patch on sides almost always fused with second transverse spot on disc. Elytral outline parallel-sided to sides faintly convergent posteriorly, very weakly flattened on disc. Postscutellar area not raised. Humeral callus prominent, impunctate. Surface moderately shiny with rather fine punctures mostly arranged in irregular rows. Intervals flat.

Pygidium yellow with apex and a large stripe on basal section black. Surface smooth, matt to moderately shiny, covered with very fine punctures and whitish, semi-erect setae.

Inferior parts of thorax totally black. Hypomera, mesoepimera and mesoepisterna relatively smooth, almost bare with scarce, rather impressed punctures. Metaepisterna and metasternum with shallower punctation and whitish, recumbent setae. Prosternal process coarsely punctured with long setae and rather short triangular apex. Abdominal ventrites black with large yellow border, shallowly and sparsely punctured, with relatively long, straight, almost regularly arranged setae. Legs totally black.

Median depression on fifth abdominal ventrite relatively deep, lengthened, matt and bare at bottom. Posterior margin of fifth abdominal ventrite weakly notched. Median lobe of aedeagus ( Fig. 9 g–k) cylindrical with triangular, quite lengthened, slightly blunt to rather pointed apex. In lateral view apex almost straight. Hairy dents moderately impressed, apparent, bearing rather long, scattered, curly setae. Aedeagal ventral surface slightly swollen in lateral view, devoid of particular structures. Endophallus ( Fig. 9f ) with sclerite I small, weakly sclerotized with denticle quite short, squat, blunt, slightly sticking out laterally. Dorsal spicule strongly developed, erected, pointed and distinctly pigmented. Sclerite II short, weakly to clearly bent near base. Arch of sclerite III low, slender, gradually blending in a regularly tapered apex, so that barely distinguishable from it. Apex of sclerite III not expanded on its proximal section. Branches of sclerite IV shorter than sclerite III in the folded-up structure, curved, with poorly broadened, rounded, almost symmetrical, microdenticulate apex and surface distinctly sculptured, covered with tiny wrinkles.

Female. BL = 4.9–5.9 mm, BW = 2.9–3.4 mm, PL = 1.6–2.0 mm, PW = 2.6–3.1 mm. Interocular distance 15.3–16.3% of BL.

Fifth abdominal ventrite in females with quite large and deep pit. Bottom of pit bald, matt, impunctate. Vasculum of spermatheca ( Fig. 9m ) rather slender, scarcely pigmented with straight proximal branch weakly swollen at base, rather short distal branch and slightly twisted, pointed apex. Ampulla fairly pigmented, slightly shifted on dorsal side of vasculum. Duct and sperm gland insertions perceptibly distinct. Duct uniform in size, slender, coiled, coils rather thick and regularly arranged. Distal not coiled portion of duct rather long, winding. Insertion on bursa copulatrix small, almost straight and slightly swollen, moderately pigmented.

Remarks. M. hamifer is the most variable species of the group regarding dorsal chromatic pattern. Paraguayan and Uruguayan material basically match the description above, which is mostly grounded on Brazilian type series. Conversely, in most of Argentinian specimens elytral yellow pattern consists of two longitudinal stripes which coalesce on apical clivus, running the inner one along suture and brushing the second one the inner side of humerous. Besides, in these specimens yellow pattern along elytral lateral margin is more extended as well towards elytral apex (chromatic form b) ( Fig. 9 c-d). A further elytral design observed in Argentinian specimens is somehow similar to the previous one, but yellow longitudinal stripes are crossed by two transversal bands so that the pattern turns out to be basically made up of five square black patches arranged in 3+2 longitudinal lines (chromatic form c, Fig. 9e ). It was not possible to detected additional morphological differences associated to these different color patterns, for that reason all the studied specimens have been considered as belonging to a single chromatically variable species.

Figures

FIGURE 9. M. hamifer. 9a–e: habitus (a–b “typical” colour pattern, c–e: chromatic variations); 9f: sclerites of endophallus [0.5 mm]; 9g–h: median lobe of aedeagus in ventral (c), dorsal (d) and lateral (e) view [0.6 mm]; 9m: spermatheca [0.9 mm]; 9n: antenna [2.2 mm]. 9a–b: lectotype; 9c–d: Argentina, Entre Rios; 9e: Argentina, Cordoba, Calamuchita, Salsacate. 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.