Metallactus languidus Suffrian, 1866

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 : 78-79

Metallactus languidus Suffrian, 1866

( Figs 7 ; 29 )

Metallactus languidus Suffrian, 1866: 373 ; Clavareau, 1913: 93; Blackwelder, 1946: 641.

Type material. I was able to track down 1♂ 3♀♀ in MNHUB and 1♂ BMNH that fit in well with the data in the original description. A second specimen in BMNH, a female from Baly collection, bears only rather “fresh” printed labels and there is no mention of the reported locality (“ Parana ”) in Suffrian's description. For that reason, this specimen was not considered a reliable syntype. The typification has been made as follows. LECTOTYPE: ♂, glued, abdomen detached and glued on the same label bearing the specimen, aedeagus extracted and glued on a separate label, // “Type Suffrian Coll Baly” [white label, handwritten] // “Baly Coll.” [white label, printed] // “ Metallactus languidus Suffr Brazil ” [recto], “Suffr Type 16 54 9 ” [verso] [white label, handwritten] // “ Metallactus languidus Suffrian, 1866 LECTOTYPUS D. Sassi des.” [red label, printed] // ( BMNH). The remaining syntypes, 1♂ 3♀ ( MNHUB), have been labelled as PARALECTOTYPES: // “ Metallactus languidus Suffrian, 1866 PARALECTOTYPUS D. Sassi des.”[red label, printed] //. One of them brings the collective labels // “23986” [white label, handwritten] / / “ languidus Suffr. *” [white label, handwritten] // “microstictus N. Brasil Sellow” //. Three other specimens are labelled // “Hist.-Coll ( Coleoptera ) Nr. 23986 Metallactus languidus Suffr * Brasil., Sello. Zool. Mus. Berlin” [green label, printed] //. The number of specimens and the label information match the registration data from the old catalogue of the MNHUB: “ languidus Suffr. 4 Brasil, Sello”).

Type locality. “ Brasilien ” .

Further material examined. BRAZIL: São Paulo Porto flor. T.C. 10.X.1933 Halik (1, USNMNH) ; Rio Grande do Sul Caracol b. Gramado 850m I.1922 E. Schirm (1, MNHUB) ; Minas Gerais Lambary XI.1924 & 26.XII.1926 Halik (2, USNMNH) ; Paranà ex coll. Baly (1, BMNH) ; Mafra 800 m. (5, MNHN) ; Lages Prov. S.ta Catharina J. Michaelis 1887 (1, MNHN) .

Distribution. Brazil.

Diagnosis. A Metallactus of medium size, quite similar to M. corruptus and M. guarani as regard size and general habitus. However, it differs from the relatives in legs and head totally black (only occasionally a faint, barely delimited yellowish spot may be present between eyes; see also the remarks below). Moreover, M. languidus normally has almost completely yellow dorsal coloration, elytral punctation generally stronger and, above all, an additional pair of small impressions on pronotal disc just in front of the usual posterolateral ones. In addition, in M. languidus the ventral profile of aedeagal tube is more flattened in lateral view (slightly swollen in M. guarani and in the examined Brazilian specimens of M. corruptus . However, in Paraguayan populations of the latter species aedeagal profile looks more similar to the one of M. corruptus ).

Description of male. Habitus in Fig. 7 a–b (LT). BL = 4.9–5.4 mm, BW = 3.0– 3.3 mm, PL = 1.5–1.8 mm, PW = 2.7–3.0 mm. Interocular distance 10.8–11.2% of BL.

Head black, sometimes with a brownish-yellow spot between eyes just above clypeus occasionally extended to upper part of frons. Labrum brownish. Surface rather lustrous, with scattered fairly impressed punctures on frons and clypeus. Vertex almost impunctate. Mid-cranial suture extended from mid of frons up to vertex, narrow but rather impressed so that vertex looks like to have two feebly, weakly prominent bumps. Setosity sparse, limited to clypeus and labrum. Antennae black with first five antennomeres somewhat lighter.

Pronotum yellow with two small subelliptical, obliquely arranged black spots on disc, sometimes almost obliterated. Pronotal shape transverse. Lateral margins narrow, slightly thicker posteriorly with maximum width behind half of length. Posterolateral impressions apparent, so that posterior margin perceptibly swollen toward sides. A second roughly rounded to subelliptical small impression just in front of the first one. Surface moderately lustrous with scattered, fairly impressed punctation, denser on sides, almost obliterated on disc.

Scutellum completely black, moderately raised, subsquared. Apex truncated to slightly rounded. Surface almost impunctate with scattered setae above all on its basal half.

Elytra yellow with black pattern consisting of three pairs of small roughly rounded spots, none of which reaching suture or margins. Outer spot of median pair placed on the same line or slightly backward in respect of the inner one. There does not seem to be tendency of spots to coalesce, but sometimes they are reduced or obliterated. Suture narrowly black. Surface dull with rather strong punctation, quite dense in particular in anterior half, with arrangement in striae clearly perceptible only towards apical clivus. Intervals flat.

Surface of pygidium yellow, smooth, covered by sparse small punctures and pale setae.

Inferior parts black with external part of hypomera and lateral sides of abdominal sternites yellow. All ventral surface covered by scattered whitish setae, quite regularly distributed, somewhat longer on metathorax. Punctuation regularly arranged and shallow, coarser on hypomera. Prosternal process longitudinally grooved with apex rounded to roughly pointed and slightly raised and surface covered with long dense pale setae. Legs black with femora sometimes with patchy brownish pattern.

Fifth abdominal ventrite with a rather shallow, smooth, bald, impunctate median depression and fairly notched posterior margin. Median lobe of aedeagus ( Fig. 7 c–e) cylindrical with smooth surface and apex triangular, short, blunt to slightly pointed, weakly bent ventrally. Hairy dents shallow, with scattered setae. In ventral view median lobe sometimes slightly swollen on sides along apical rim at base of apex. Ventral profile weakly swollen in lateral view.

Endophallus ( Fig. 7 f–g) with sclerite I well sclerotized with denticle moderately developed, blunt, pointing forwards. Dorsal spicule well developed, pointed and fairly pigmented. Sclerite II long, weakly bent near base. Sclerite III low, so poorly projecting upwards with arch slender with a long tapered straight apex. Branches of sclerite IV fairly higher than sclerite III in the folded up structure, straight, with rounded, slightly asymmetrical, microdenticulate apex and surface fairly sculptured, covered by small wrinkles.

Female. BL = 5.4–6.1 mm, BW = 3.4–3.8 mm, PL = 1.8–2.0 mm, PW = 2.9–3.4 mm. Interocular distance 14.9–15.0% of BL.

Fifth abdominal ventrite in females with a rather shallow pit, almost circular, black. Spermatheca ( Fig. 7h ) with upper and lower branches of vasculum relatively thin. Upper branch gradually tapered, so apex barely distinct. Lower branch vaguely bent near base. Ampulla dorsally placed with insertions of gland and duct slightly divergent. Duct tightly coiled in proximal and median part, gradually loosened in the last section. Insertion on bursa copulatrix swollen, twisted, fairly pigmented. Rectal apparatus ( Fig. 7 k–m) with dorsal sclerites moderately tapered towards median line and apodemes apparent, bent upwards and leaning against rectum. Ventral sclerite large, ribbon-like, deep, faintly tapered on sides, lighter on its central section, with deep apodemes, fairly protruding and crenulate on margin.

Remarks. Color pattern is constant in the examined specimens, but one female from the surrounding area of Chamado (Rio Grande do Sul) looks quite distinct having larger pronotal black spots, head almost entirely yellow, posterior pair of elytral spots confluent in a transverse band, mid and hind femora partly yellow.

Figures

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 29–36. Distribution maps for Metallactus kollari species-group. M. languidus (29); M. londonpridei (30); M. longicornis (31); M. patagonicus (32); M. pollens (33); M. regalini (34); M. rileyi (35); M. spilotus (36). Grey squares: localities reported in a generic way.