Mylassa fuliginosa, 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 : 328-330

Mylassa fuliginosa sp. nov.

urn:lsid:zoobank.org:act:

( Figs. 7a–c ; 13c ; 25a ; 27b )

Types. HOLOTYPE: CHILE: Biobío: ( MSNM), ♀, body and detached abdomen glued on same card, genitalia glued on different card, // “ CHILE XII.58 Cord. Nahuelbuta Pichinahuel” [white label, printed, date handwritten] // “ Mylassa fuliginosa sp. nov . HOLOTYPUS D. Sassi des.” [red label, printed] //. PARATYPES (2): CHILE: Biobío: ( DSPC), ♀, same data of the holotype; ( DSPC), ♀, // “ CHILE I.59 Cord. Nahuelbuta Pichinahuel” [white label, printed, date handwritten] //. Both paratypes also labelled: // “ Mylassa fuliginosa sp. nov . PARATYPUS D. Sassi des.” [red label, printed] //.

Type locality. Cerro Pichinahuel ( Cordillera de Nahuelbuta , Región del Biobío, Chile) .

Etymology. The species name fuliginosa derives from the Latin fuliginosus meaning ‘sooty’ or ‘smoky,’ in reference to the dull black coloration of the body.

Distribution. Chile ( Biobío).

Biological notes. No data available.

Diagnosis. Mylassa fuliginosa is of relatively large size, easily distinguished from other species by its rather stout shape and almost oval outline, and especially by its entirely black coloration and opaque tone of the elytral surface, due to the dense micropunctation of interstriae, which are traversed by regular rows of closely appressed, white setae.

Description of female (male unknown). Habitus in Figs. 7a–c (HT). BL = 4.0– 4.3 mm, BW = 2.6–2.7 mm, PL = 1.4–1.8 mm, PW = 2.4–2.5 mm. Interocular distance 16.3–17.5 % of BL.

Head totally black. Vertex and frontoclypeal surface covered with well-impressed, regularly distributed punctation and thick, long, appressed, whitish setae; mid-cranial and frontoclypeal sutures not detectable. Eyes large, bulging, only shallowly notched on inner margin with upper lobes well separated from each other. Ocular lines barely visible. Antennae black, sometimes with lighter patches, especially on basal segments, short, scarcely reaching elytral middle when bent backwards; antennomeres 3–5 subcylindrical; 6–10 slightly flattened; 4–11 scarcely differing in length.

Pronotum totally black, regularly convex, bulging. Lateral margins narrow, not visible from above, regularly and mildly arched, converging towards anterior margin so that maximum width about at basal margin. Posterolateral impressions short and weakly impressed, close to posterior margin. Pronotal surface covered with close, well-impressed, regularly distributed shallow punctation and thick, appressed, whitish setae. Posterior lobe large, slightly convex with apex truncated in straight line.

Scutellum black, triangular, pointed, not raised, setose and regularly punctured.

Elytron totally black. Elytral outline cylindrical, regularly convex, with sides slightly convergent toward apex. Lateral margins narrow, not visible from above. Scutellar area not raised. Humeral callus moderately prominent, not punctured. Elytral surface with punctures arranged in well-impressed, regular rows. Interstriae finely rugulose, covered with thick semi-appressed, whitish setae. Epipleura narrow, setose, with plane, finely punctured surface.

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

Ventral surface black, matt, finely and densely punctured, with short, appressed setae, except scarcely setose, shiny posterior part of hypomera and mesoepimera. Prosternal process wide, short, roughly squared; sides with sharp denticle at middle; surface with scattered punctures and sparse, long setae; posterior margin not raised, slightly notched at middle.

Legs completely black. Tibiae with no modifications, only mildly curved inward towards apex.

Fifth abdominal ventrite with shallow rounded pit with flat, almost bald, not punctured, shiny base.

The vasculum of spermatheca ( Fig. 25a ) is slender, hook shaped. Lobes of vasculum not swollen, distal one shorter than proximal one. Ampulla long, subcylindrical and weakly pigmented. Duct insertion and sperm gland insertion fully separate, the latter sitting on apex of ampulla. Duct short, coiled, with its proximal half surrounded by rigid and opaque sleeve.

Figures

FIGURE 7. Mylassa fuliginosa. a–c: female, habitus in dorsal (a), lateral (b) and frontal (c) view (PT, Cord. Nahuelbuta Pichinahuel, Chile). Mylassa ferruginea. d–f: female, habitus in dorsal (d), lateral (e) and frontal (f) view (HT, “Paraguay”). 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 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.