Astylus tucumanensis Pic, 1902

Estrada, Patricia, 2021, Updating the knowledge of species of the genus Astylus Laporte (Coleoptera Melyridae) from South America, Zootaxa 4941 (1), pp. 127-141 : 137-139

Astylus tucumanensis Pic, 1902

( Figures 10–13)

Astylus tucumanensis Pic, 1902:34 ; Pic 1908:329; Bruch 1915:251; Pic 1919a:3 ( Astylus ( Microastylus )); Pic 1919c:188; Pic 1929:13; Blackwelder 1945:379; Estrada 2008:601. (Type locality: Tucumán).

Types examined: tucumanensis : one male herein designated as lectotype and labelled as follows: tucumanensis Pic. ; R. A. Tucumán marzo 6/1899; Type. ( MNHN)

Diagnosis. Head and pronotum black with abundant and sparse pilosity ( Fig.10); antennae moderately serrated ( Figs. 11a ; 12a ); pronotum wider in the middle, with flattened sides; elytra with two longitudinal and subparallel carinae on the disc, with prominent humeral and subapical angles. Females: ventrite 5 with marked notch in the center of the distal margin ( Fig. 11b ); ventrite 6 with two transversal plates convergent at middle; last tergite rounded apically and slightly emarginated medially ( Fig 10b); ovipositor with a fine linear sclerite at the middle on the dorsal plate ( Fig. 11c ). Males: ventrite 1 with a central, trilobular process, close to basal margin; ventrites 2–5 widely emarginated in the middle at the distal margin; ventrite 6 and last tergite are fused like a subconical structure; ventrite 6 has two longitudinal lateral carinae, and a moderately emarginated distal margin ( Fig. 12b ); last tergite has a narrow apical projection ( Fig. 12b ); sclerotized parameres, with sides converging distally and a pre-apical narrowing; apex slightly emarginated in the middle, widened towards the sides and strongly curved ventrally ( Fig. 13a,b ); lateral edges are also curved ventrally and fused at apex; moderately widened tegminal arms that are curved at the sides; tegminal plate broad with a dorsal elevated fold at the midline ( Fig. 13c ). Median lobe subcylindrical, elongated, sclerotized, with a subcylindrical and strongly curved apex, phallotreme subapical ( Fig. 13 d–f).

Description: Average body length 7.7 mm (range: 7.0–8.0, n= 12; males and females); length: width ratio 2.7:1, sides sub-parallel; moderately abundant thick erect black hairs on the dorsal surface; dense, fine, decumbent, light gray pilosity on the ventral surface; pronotum black with abundant coarse punctures; elytra with dense coarse punctuation and abundant erect dark hairs; orange disc with four black longitudinal bands, frequently with a black dot adjacent to the apex ( Fig.10); antennae and legs are orange, with dark testaceous to black margins.

Head: Including the eyes, slightly narrower than distal margin of pronotum (0.9:1); front moderately depressed between the eyes; frontoclypeal region prolonged and narrowed toward the apex; antennae slightly longer than the length of the pronotum (1.2:1), antennomeres 3–10 moderately serrated ( Fig. 11a ; 12a ).

Thorax: Pronotum slightly longer than wide (1.2:1), moderately convex transversely, widest at the middle; marked distal, lateral, and basal margins, sides slightly flattened, basal margin narrower than humeral region (0.4:1). Elytra longer than wide (4.4:1), prominent humeral angle, subparallel lateral margins in the two basal thirds, and slightly rounded in the distal third; disc slightly convex in the middle and moderately bent at the sides and at the apex, with a marked subapical angle; narrow, glabrous and smooth epipleura, sides converging at apex. Legs: elongated, slender, abundant bristles in external margin of tibiae, tarsomeres with fine ventral spines, toothed claws.

Abdomen: Female: ventrite 5 with marked notch in the center of the distal margin ( Fig. 11b ), ventrite 6 free, not fused with last tergite, consisting of two flat, transversal plates, convergent at middle, spiculum ventrali longer than the ventrite 5 (2:1); last tergite rounded apically and slightly emarginated medially ( Fig. 11b ); Genitalia: ovipositor with a fine linear sclerite at the middle on the ventral plate, as long as the oblique baculi (1:1), ventral baculi longer than the oblique baculi (2.5:1) with irregular basal widening; fine, long proctiger baculi, longer than the ventral baculi (2.3:1) ( Fig. 11c,d ); ventral and dorsal laminae densely pubescent.

Males: Ventrite 1 with a prominent, trilobular process at the middle, close to the basal margin ( Fig. 12b ); ventrites 2–5 broadly emarginated at the middle in the distal margin; ventrite 6 and last tergite fused like subconical structure; ventrite 6 with two prominent and longitudinal carinae at the middle, with a moderately emarginated distal margin; last tergite with narrow projection at the apex ( Fig. 12b ); segment 9 with a fine tergum, wide sternal arms, fine and long apodeme ( Fig. 12c ). Genitalia: sclerotized parameres, with sides converging distally and moderately emarginated at the base with a preapical narrowing, apex slightly emarginated in the middle and widened towards the sides, strongly curved ventrally, lateral edges curved ventrally and fused at the apex ( Fig. 13 a–c). Tegmen with a lateral flange at the base of the parameres, moderately widened tegminal arms, curved at the sides, gradually narrowed, curved and convergent toward the base and strongly curved at the base from a lateral view; tegminal plate broad, strongly emarginated at distal margin with a dorsal elevated fold at the midline, slightly projected on the apodeme; wide and securiform apodeme, consisting of two divergent laminae ( Fig. 13 a–c). Median lobe subcylindrical, elongated, and sclerotized with sub-parallel sides, from a lateral view, with moderate ventral constriction at the base; apex sub-cylindrical, strongly curved ventrally, phallotreme subapical; enlarged apodeme, basally widened ( Fig. 13 d–f).

Distribution ARGENTINA, Tucumán Province: Tucumán (MNHN), 1♁; Tucumán (IFML) 2♁; Parque 9 de Julio (IFML) 1♀, Tucumán (MACN) 3♁. BRASIL: Minas Gerais Province: Passos (DZUP) 1♁, Pocos Caldas (DZUP) 1♁; Paran Province: Cándido de Abreu (DZUP) 2♁; Sao Paulo Province, Santana (DZUP) 1♀.

According to the collection data of the material reviewed in this study, the geographic distribution of Astylus tucumanensis corresponds to the Chacoan and Cerrado Provinces in the Chacoan dominion and the Atlantic, Parana Forest and Araucaria Forest Provinces in the Parana dominion of the Neotropical region ( Morrone 2014, 2018).

Remarks. Pic (1908) described subdisjuncta as a variety of A. tucumanensis using material from Bolivia. However, no catalog mentions it as such, Pic (1929) and Blackwelder (1945) list Astylus subdisjunctus Pic, 1908 in a species category with distribution in Bolivia. In the original description of the subdisjuncta there is not mentions to the abdominal process in males, with which the author defines Microastylus using A. tucumanensis as an example ( Pic, 1902). As such, the type material of Astylus tucumanensis var. subdisjuncta should be reviewed to verify if, indeed, it is a different species or synonyms of A. tucumanensis .

Figures

FIGURE 11. Astylus tucumanensis Pic, 1902. Female, a: antenna; Terminal segments of abdomen: b: v: V ventrite, vi: VI ventrite and lt: last tergite; bo: baculi oblique, bd: dorsal baculi, ld: dorsal laminae, bp: proctiger baculi; c: segment 9. Scale 1 mm.

FIGURE 12. Astylus tucumanensis Pic, 1902. Male, a: antenna; Terminal segments of abdomen: b: v: V ventrite, vi: VI ventrite and lt: last tergite, pa: abdominal process; c: segment 9. Scale 1 mm.

FIGURE 13. Astylus tucumanensis Pic, 1902. Male genitalia. Tegmen and parameres: a: dorsal view; p: parameres; b: ventral view; c: lateral view, ap: apodeme, Scale 1mm. Median lobe: d: dorsal view, pha: phallotreme; e: ventral view; f: lateral view. Scale 1 mm.