Mylassa flavolimbata, Sassi, 2025

Sassi, Davide, 2025, Taxonomic revision of the South American genus Mylassa Stål, 1867 (Coleoptera: Chrysomelidae: Cryptocephalinae) with the description of eight new species, Zootaxa 5683 (3), pp. 301-359 : 330-332

Mylassa flavolimbata sp. nov.

urn:lsid:zoobank.org:act:

( Fig. 8 ; Figs. 13d ; 17a–c ; 25b ; 27d )

Types. HOLOTYPE: CHILE: Maule: ( MSNG), ♂, body and detached abdomen glued on same card // “ CHILE, CE, reg. VII Linares Robleria env. 23.XI.2003 Leg. M. Snížek ” [white label, printed] // “ Museo Genova ex coll. M. Snizek acquisto 2010” [white label, printed] // “ Mylassa flavolimbata sp. nov . HOLOTYPUS D. Sassi des.” [red label, printed] //. PARATYPES (22): CHILE: Maule: ( MSNG), 3♂, same data of the holotype; ( MSNG), 6♂ 8♀, // “ CHILE, CE, reg. VII Longaví, El Transito env. 22.XI.2003 Leg. M. Snížek ” [white label, printed] // “Museo Genova ex coll. M. Snizek acquisto 2010” [white label, printed] //; ( DSPC), 1♀, // “ CHILE XII.57 Cord. Parral Fundo [Puente?] Malcho” [white label, printed, date handwritten] //; ( MSNG), 1♂, // “ CHILE, CE, reg. VII Talca, 27.XI.2003 W of Vilches Alto Leg. M. Snížek ” [white label, printed] // “Museo Genova ex coll. M. Snizek acquisto 2010” [white label, printed] //. Ñuble: ( MSNG), 1♀, // “ CHILE, CW, reg. VIII SW of Quirihue, 4.XII.2003 Leg. M. Snížek ” [white label, printed] // “ Museo Genova ex coll. M. Snizek acquisto 2010” [white label, printed] //; ( HNHMB), 1♂, // “Chile” [white label, printed] // “ Cryptocephal. sp. coll. Geitner ” [white label, partly printed] //; ( DSPC), 1♂, // “ CHILE Bulileo [sic] [Embalse Bullileo] [white label, printed].All paratypes also labelled: // “ Mylassa flavolimbata sp. nov . PARATYPUS D. Sassi des.” [red label, printed] //.

Type locality Robleria ( Provincia de Linares , Región del Maule, Chile) .

Additional material examined. Pictures of this species (apparently the same specimen) are showed on iNaturalist (https://www.inaturalist.org/observations/196607424 and https://www.inaturalist.org/observations/196301354), reported from the neighborhood of Purén, Araucanía, Chile).

Etymology. The species name flavolimbata derives from the Latin flavus (‘yellow’) and limbatus (‘bordered’), referring to the broad yellow pattern along the sides of the elytra.

Distribution. Chile ( Araucanía, Maule, Ñuble) (first Region from some iNaturalist records).

Biological notes. No data available.

Diagnosis. Mylassa flavolimbata belongs to the subgroup of small-sized species with black elytral coloration featuring a lateral-median yellow spot and a second one at the apex of the elytron. Among these species, the most similar is M. longicornis , from which it can be distinguished by the larger and differently (longitudinally) arranged lateral yellow spot. In M. daccordii , the elytral yellow spots are decidedly smaller (sometimes almost obliterated), and the punctation of the pronotum is distinctly more pronounced and spaced. Besides, the shape of median tibiae is unique among the known species, being sharply compressed and bent inwards at apex. Additionally, in M. daccordii the antennomeres are shorter and evidently flattened (long and filiform in M. flavolimbata ).

Description of male. Habitus in Figs. 8a–c (PT). BL = 2.6–2.8 mm, BW = 1.6 mm, PL = 1.0– 1.1 mm, PW = 1.4–1.5 mm. Interocular distance 17.9–19.2 % of BL.

Head totally black. Vertex and frontoclypeal surface covered with well-impressed, regularly distributed punctation and scattered short whitish setae; mid-cranial and frontoclypeal sutures not clearly detectable. Eyes large, bulging, only shallowly notched on inner margin with upper lobes well separated from each other. Ocular lines scarcely impressed, barely visible. Antennae long, reaching elytral clivus when bent backwards, antennomeres slender, black (2–3 slightly lighter), minutely setose; antennomeres 4–11 subcylindrical, scarcely different from each other in length and shape.

Pronotum totally black, convex. Lateral margins narrow, not visible from above, almost straight, weakly converging towards anterior margin so that overall outline almost square, maximum width about at basal margin. Posterolateral impressions long, obliquely departing from posterior margin towards sides, well impressed so that central part of disc looking fairly bulging. Pronotal surface covered with close, regularly distributed, very fine punctation. Posterior lobe slender, slightly convex with apex truncated in straight line.

Scutellum black, triangular, pointed, not raised, bare, rather coarsely punctured.

Elytron black with large, elliptical, longitudinally arranged yellow spot extended from humeral callus to just behind middle, between fourth and ninth rows of punctures; further yellow spot at apex. Elytral outline cylindrical, regularly convex, with sides parallel, i.e. not convergent toward apex. Lateral margins narrow, not visible from above. Scutellar area not raised. Humeral callus scarcely prominent, not punctured. Elytral surface bare, with punctures arranged in well-impressed, almost regular rows; in studied specimens, punctuation on central part of disc scarcely visible as surface covered by fine but thick roughness. Epipleura narrow, with weakly concave, slightly rugose surface.

Pygidium black, matt, covered by very fine punctures and short, appressed setae.

Ventral surface black, matt, finely and densely punctured, with short, appressed setae, except scarcely setose, shiny posterior part of hypomera. Prosternal process wide, short and transverse, basically flat at centre; sides with sharp, thorn-shaped denticle at middle; posterior margin raised at middle in pointed process; surface minutely punctured, with sparse, long setae.

Legs completely black.Anterior tibiae strongly bent at apex, with apical, sharp denticle forwards directed. Median tibiae strongly compressed and bent inwards at apex, with sharp apical denticle.

Fifth abdominal ventrite devoid of median depression along posterior margins. Posterior margin of fifth abdominal ventrite straight.

Median lobe of aedeagus ( Figs. 17a–c ) moderately lengthened. Ventral surface weakly concave, smooth, devoid of longitudinal carina. Shaft terminated with weakly pointed, shortly triangular apical edge. Setose depressions shallow, barely delimited, with setae thicker on apical end. Setigerous lamellae small, roughly elliptical with few short apical setae.

Female. Habitus in Figs. 8d (PT). BL = 3.4 mm, BW = 2.0 mm, PL = 1.3 mm, PW = 1, 9 mm. Interocular distance 20.6 % of BL.

The single available female differs in larger size, slightly larger ocular distance, stouter outline, absence of sexual modification on the anterior and median tibiae, and shorter antennae which scarcely extend past midline when bent backwards.

Fifth abdominal ventrite with shallow rounded pit with a flat, scarcely setose, not punctured base.

Vasculum of spermatheca ( Fig. 25b ) slender, moderately pigmented, hook-shaped, with proximal and distal lobes not swollen, the latter slightly shorter, mildly tapered to pointed, down-turned apex. Proximal lobe fairly bent at base. Ampulla lengthened, cylindrical. Duct insertion and sperm gland insertion fully separate, the latter sitting at proximal end of ampulla. Duct short, coiled. Proximal section embedded in a thickened, rigid sleeve.

Figures

FIGURE 8. Mylassa flavolimbata. a–c: male, habitus in dorsal (a), lateral (b) and frontal (c) view (PT, Embalse Bullileo, Ñuble, Chile); d–f: colour variations (PTs, Longaví, El Transito, Maule, Chile, (d: female; e–f: males)). Images not to scale.

FIGURE 13. Pronotum. a: Mylassa rubronotata (Curicó E. of Potrero Grande, Maule, Chile); b: M. monrosi (HT, Antillanca, Los Lagos, Chile); c: M. fuliginosa (PT, Cord. Nahuelbuta Pichinahuel, Chile); d: M. flavolimbata (PT, Embalse Bullileo, Ñuble, Chile). Images not to scale.

FIGURE 17. Median lobe of the aedeagus in ventral (left), dorsoapical (center) and lateral (right) views. a–c: Mylassa flavolimbata (PT, Embalse Bullileo, Ñuble, Chile); d–f: M. daccordii (PT, Lonquimay, Araucanía Chile); g–i: M. postmediana (HT, Algarrobo, Valparaíso, Chile). All images in the figure courtesy of Michele Zilioli (MSNM).

FIGURE 25. Spermatheca. a: Mylassa fuliginosa [scale bar = 0.4 mm]; b: M. flavolimbata [scale bar = 0.4 mm]; c: M. daccordii [scale bar = 0.4 mm]; d: Mylassa longicornis [scale bar = 0.3 mm]; e: M. ferruginea [scale bar = 0.6 mm]; f: M. mirabilis [scale bar = 0.5 mm].

FIGURE 27. Distribution maps. a: Mylassa monrosi; b: M. fuliginosa (circle), M. longicornis (stars), M. ferruginea (large star); c: M. mirabilis (circles), M. postmediana (star); d: M. flavolimbata (circles), M. daccordii (stars). Large star in Fig. 27b (M. ferruginea): available data indicate the presence in Paraguay, but without precise locality information.