Astylus lineatus ( Fabricius, 1775 )

Estrada, Patricia, 2023, New contribution to the knowledge of the neotropical species of the genus Astylus (Laporte, 1836) (Coleoptera: Melyridae), Zootaxa 5227 (3), pp. 355-364 : 356-362

Astylus lineatus ( Fabricius, 1775)

( Figures 1–7 )

Anobium lineatum Fabricius, 1775: 62 ; Fabricius, 1781: 72

Lagria lineata Fabricius 1787: 94 ; Fabricius 1792: 80

Melyris lineatus Olivier 1790: 217 ; Olivier 1792: 656; Olivier 1808: pl 61 fig. a,b

Dasytes lineatus Fabricius 1808: 72 ; Schoenherr 1817: 16; Laporte 1840: 281; Blanchard 1843: 98

Astylus lineatus Lacordaire 1857: 406 ; Redtenbacher 1868: 109; Gemminger & Harold 1869: 1718; Champion 1818: 352; Pic 1929: 16; Blackwelder 1945: 378

(Type locality: Brasilia).

Arthrobrachus subacuminatus Solier, 1849: 417 ; Estrada & Solervicens 1999: 79.

(Type locality: Concepción—Araucanie). n.syn.

Astylus lineatus var. inlineatus Pic, 1919: 21 .

(Type locality: Bresil). n.syn.

Astylus lineatus var. janeirensis Pic, 1919: 21 .

(Type locality: Río de Janeiro). n.syn.

Types examined: lineatus : Lagria lineata Fabr. Mant. Ins. p. 94 n. 20; NHMUK015016027 (NHMUK). lineatus : Type; NHMUK015016028 (NHMUK). var. inlineatus : A. lineatus var. inlineatus Pic syntype; Brésil; Museum Paris, Coll. M. Pic; MNHN, Paris, EC17077 (MNHN). var. janeirensis : A. lineatus var. janeirensis Pic , syntype; Rio Janeiro; Museum Paris, Coll. M. Pic; MNHN, Paris, EC17078 (MNHN). subacuminatus : Arthrobrachus subacuminatus Solier , Araucania; syntype; Concepción, Araucanie; Nº33; MNHN, Paris, EC17143. (MNHN).

Diagnosis. Body elongated, subparallel sides, dorsal and ventrally pilose, with abundant erect black hairs on head, pronotum and elytra and dense light hairs on thoracic sternum and ventrites. Elytra with a particular colour pattern typically black with three orange or reddish lines with irregular edges, one marginal, another on the disc, short or absent, and a third on the dorsal area of the disc curved towards the suture. Females: antenna slightly serrated; ventrite 6, subtriangular, with V-shaped indentation on distal margin, last tergite subtriangular, apex with two processes at the center and projected backward; membranous ovipositor. Males: antenna filiform; ventrite 1 with a short central process at the middle, ventrite 5 strongly emarginated at the distal margin; ventrite 6 and last tergite fused like a subconical structure; ventrite 6 slightly convex at the distal margin, last tergite, with a narrow and convex apical projection at the margin, with an irregular and globose posterior edge; Genitalia: Parameres sclerotized at the base, subparallel-sided, fused at base; median lobe subcylindrical; apex elongate, moderately widened and rounded; subapical phallotreme, oblong, at the base projecting in a linear groove to almost half of median lobe.

Description: Body elongated, females average body length 7.2 mm (range: 7–7.5, n=7); length: width ratio 3.3:1; males average body length 6.8 mm (range: 6.4– 7.2 n =3), length: width ratio 3.1:1; subparallel sides; abundant coarse, erect black hairs and abundant light, fine, decumbent hairs on the head, pronotum, legs and ventral surface; scutellum with fine, decumbent light pilosity, dense light hairs on thoracic sternum and ventrites; pronotum and elytra with abundant coarse punctures; antennae and legs reddish or dark testaceous. Elongate, black elytra with three broad reddish bands with irregular edges, one marginal, another on the disc, short or absent, and a third one that starts at the base, adjacent to the humeral angle and advances along the dorsal area of the disc curving towards the suture ( Figs. 1–3 ).

Head: Including the eyes, slightly wider than the distal margin of the pronotum (1:11); front slightly depressed between the eyes; frontoclypeal region slightly prolonged and narrowed toward the apex; antennae longer than the length of the pronotum (1.6:1); antennae of males filiform, elongated and subcylindrical antennomeres, the last two slightly widened on the mesal side ( Fig. 4a ); female antennomeres 4–10 slightly serrated ( Fig. 4b ).

Thorax: Pronotum slightly wider than it is long (1.1:1) ( Fig. 1–3 ), and moderately convex transversely, widest at the middle; distal, lateral and basal margins are well marked, lateral margin is slightly flattened, basal margin slightly narrower than humeral region (0.9:1), pronotal disc with decumbent gray hairs denser near the margins and in the center forming a longitudinal median line. Elytra longer than wide (6.3:1) ( Fig. 1–3 ), with a marked humeral angle; subparallel sides that are slightly rounded towards to apex; disc slightly convex, slightly marked subapical angle; wide, pilose epipleura, internal margin with scarce denticles, and sides converging at the apex. Legs: elongated, slender, moderately scarce bristles in the external margin of the tibiae; tarsomeres longer than wide, with scarce, fine ventral spines; toothed claws.

Abdomen: female: Ventrite 5 with concave distal margin; ventrite 6 and last tergite not fused; Ventrite 6, subtriangular, with V-shaped indentation on distal margin, medially with two short, subparallel folds, spiculum ventral fine, longer than ventrite 5 (1.4:1); last tergite subtriangular, apex with two processes at the center and projected backward ( Fig. 5a ); Genitalia: membranous ovipositor; ventral baculi longer than the oblique baculi (2:1) and slightly widened at the base; fine, long proctiger baculi, longer than the ventral baculi (1.5:1) ( Fig. 5b,c ); ventral and dorsal laminae with scarce pubescence.

Males: Ventrite 1 with a short central process at the middle, close to the basal margin ( Fig. 6a pa); ventrite 5 strongly emarginated at the distal margin ( Fig. 6a v ); ventrite 6 and last tergite fused like a subconical structure; ventrite 6 slightly convex at the distal margin with a slight submarginal sinuous depression at the base ( Fig. 6b vi, lt); last tergite, with a narrow and convex apical projection at the margin, with an irregular and globose posterior edge ( Fig. 6b vi, lt); segment 9 with thin, membranous terga, thin sternal arms at the sides and broad at the base and a narrow, elongated apodeme ( Fig. 6c ); Genitalia: Parameres sclerotized, subparallel-sided, fused at base, convergent at apex ( Fig. 7a,b p ); tegminal arms moderately thick, strongly curved at base; tegminal plate broad with a slightly raised dorsal fold in midline, projecting toward base; apodeme broad and securiform, consisting of two parallel lamellae ( Fig. 7c ap). Median lobe subcylindrical, sclerotized, elongate and strongly curved at base; apex elongate, moderately widened and rounded; phallotreme, broad, subapical projecting in a thin linear depression running nearly halfway down body of median lobe ( Fig.7d pha); apodeme elongate, widening at base ( Fig. 7f ap).

Distribution. PERU, Tarma Province: Tarma, 3050 msnm, (IFML) 3♀. Acobamba, (IFML) 1♀. BRASIL, Brasil ( DZUP) 1♀, ( MNHN) 1♀. ( NHMUK) 2♁. Estado Rio de Janeiro : Ilha do Governador , ( DZUP) 1♀; Galeão , (DZUP) 1♀. Río de Janeiro (MNHN) 1♁.

According to the geographic data of the original descriptions and the revised material, the species Astylus lineatus would be distributed between the Atlantic Province of the Chacoan Domain in Chacoan Subregion and the Yungas Province of the South Brazilian Domain in the Brazilian Subregion of the Neotropical region sensu Morrone (2014, 2022).

Remarks. The review of the Chilean species of the genus Astylus ( Estrada 2002) and the contributions of the author regarding the genus Arthrobrachus in Chile ( Estrada & Solervicens 1999; Estrada 2003, 2005) allow to point out that no specimens of A. subacuminatus have been recorded in Chile. The geographical data of the specimens of Astylus lineatus studied, place the species in the Neotropical region (Chacoan and Brazilian sub-regions) ( Morrone, 2014; Morrone et al., 2022) different from the southern part of Chile, which corresponds to the Andean region (Subantartic sub-region) ( Morrone 2015). From what is known, it is not possible to assume that this is a lack of geographical information on the species, but rather an error in the labelling of the specimen reviewed by Solier (1849).

Figures

FIGURE 1. Astylus lineatus (Fabricius, 1775), syntypes (a,b). Scale:1mm. Photo by Keita Matsumoto Copyright Natural History Museum, London. Scale 1 mm.

FIGURE 2. Astylus lineatus (Fabricius, 1775) var. inlineatus (Pic, 1929) n.syn. syntype (a); Astylus lineatus (Fabricius, 1775) var. janeirensis (Pic, 1929) n.syn. syntype (b). Scale 2 mm. Photos by Christophe Rivier & Lilou Leonetti, Copyright Muséum National d’Histoire Naturelle de Paris.

FIGURE 3. Astylus lineatus (Fabricius, 1775), Astylus subacuminatus (Solier, 1849) n.syn. Syntype Scale 2 mm. Photos by Christophe Rivier & Lilou Leonetti, Copyright Muséum National d’Histoire Naturelle de Paris.

FIGURE 4. Astylus lineatus (Fabricius, 1775). Antenna; female (a), male (b). Scale 1 mm.

FIGURE 5. Astylus lineatus (Fabricius, 1775). Female, terminal segments of abdomen, v: V ventrite, vi: VI ventrite and lt: last tergite (a); Ovipositor, bo: baculi oblique, bv: ventral baculi, vl: ventral lamina (b); dl: dorsal lamina, bp: proctiger baculi (c). Scale 1 mm.

FIGURE 6. Astylus lineatus (Fabricius, 1775). Male, terminal segments of abdomen, v: V ventrite, pa: abdominal process (a) Scale 1 mm; vi: VI ventrite and lt: last tergite (b); segment 9 (c). Scale 1 mm.

FIGURE 7. Astylus lineatus (Fabricius, 1775). Male genitalia. Tegmen and parameres: dorsal view, p: parameres (a); ventral view (b); lateral view, ap: apodeme (c), Scale 1mm. Median lobe: dorsal view, pha: phallotreme (d); ventral view (e); lateral view, ap: apodeme (f). Scale 1 mm.