Arthrobrachus longipilis Pic, 1919

Estrada, Patricia, 2020, Contributions to knowledge of Arthrobrachus Solier, 1849 (Coleoptera: Melyridae) A redescription of Arthrobrachus forsteri Wittmer, 1958 and A. longipilis Pic, 1919, Zootaxa 4751 (3), pp. 582-588 : 585-587

Arthrobrachus longipilis Pic, 1919

( Figures 4–5 )

Holotype: Argentina , Holotype. Housed in National Museum of Natural History in Paris, ♂ .

Diagnosis. Body has conspicuous fine and long hairs on dorsal surface, hairs as long as or longer than two dis-

tal antennomeres. Dense and shorter pubescence on ventral surface. Antennae generally have four dilated preapical antennomeres ( Fig. 4a ); pronotum has rounded distal and basal angles; ventrite 6 has a single transverse plate ( Fig. 4b ); last tergite is elongated, posterior edge has a projected flange on the inner face ( Fig. 4b ), with dense and long hairs; parameres are slightly sclerotized, narrow lateral edges, linear at apex ( Fig. 5a ); tegmen has no dorsal flange, tegminal plate is reduced and flat, narrow tegminal arms, convergent in the basal area ( Fig. 5a ); median lobe is thick, subcylindrical, with no flection area ( Fig. 5 c–e).

Description: Male: body length 4 mm, length: width ratio as 1.25:1, sides subparallel; pronotum and elytra with distinct coarse punctures; pubescence fine, with hairs as long or longer than two distal antennomeres, dense on dorsal surface, dense and shorter on ventral surface; body dark testaceous, antennae and legs light testaceus.

Head: Including the eyes, slightly wider than the distal margin of the pronotum (1.1:1); antennae shorter than the length of the pronotum (0.75:1), with four dilated, rounded preapical antennomeres ( Fig. 4a ).

Thorax: Pronotum wider than it is long (1.7:1), moderately convex transversely and slightly curved longitudinally, the base as wide as the apex (1:1) and narrower than the humeral region (0.8:1), from a dorsal view the distal margin is slightly convex, distal and basal margins are well marked, lateral margins are slightly curved; distal and basal angles are rounded. Elytra 1.9:1 longer than it is wide; lateral margins are subparallel in the two basal thirds and rounded in the distal one; disc is moderately convex, with light lateral border; epipleura are narrow, grainy and hairy, with small apical denticles. Legs: median and hind tibiae with scarce and small spines in the external margin, tarsomeres with few ventral spines.

Abdomen: Ventrite 5 with distal margin convex laterally, projected medially and with an emargination at center; ventrite 6 not divided well emarginated at center; last tergite is elongated, posterior margin almost straight with a projected flange on the inner face ( Fig. 4b ), as long as a third of the length of the tergite, with dense and long hairs; segment 9 is sclerotized, with a narrow tergum, fine sternal arms and a short apodeme ( Fig. 4c ). Genitalia: parameres slightly sclerotized, narrow lateral edges curved, communicated at apex with a linear sclerite, in a straight line with the arms of the tegmen ( Fig. 5 a,b ); tegmen without dorsal flange, tegminal plate reduced and flat, tegminal arms narrow, convergent at the base; apodeme reduced ( Fig. 5a,b ); median lobe body, sclerosed, thick, subcylindrical, no flection area at the base; phallotreme oval; apex acuminated at center; in lateral view, strongly curved at base; apodeme is wide and open ventrally ( Fig. 5 c–e).

Type locality: Argentina

Remarks. Here, the type locality has been considered to be Argentina, as the A. longipilis holotype label indicates. However, the catalogs of Pic (1929) and Blackwelder (1945) consign A. longipilis to Paraguay.

Acknowledgements

To the Research Office of the Universidad Metropolitana de Ciencias de la Educación by funds granted to the project DIUMCE 09/2019-APIX. My thanks for the facilities provided in the revision of material to Mrs. Azadeh Tghavian of the National Museum of Natural History in Paris, to Dr Michael Balke and Mrs. Ditta Amran Balke of Zoologische Staatssammlung München in Munich, MSc. Emilia C. Pérez and Dra. Liliana Valverde for the loan of material of Fundación e Instituto Miguel Lillo of Universidad Nacional de Tucumán, San Miguel de Tucumán, Argentina. My thanks to Jaime Solervicens A. and Christian R. Gonzalez A. for their suggestion to the manuscript, to Ditta Amran Balke for the A. forsteri picture, courtesy of the Coleoptera Section of the ZSM.

Figures

FIGURE 4. Arthrobrachus longipilis. a: Antenna. Terminal segments of abdomen: b: v: V ventrite, vi: VI ventrite, lt: last tergite and fla: flange; c: IX segment. Scale 1 mm.

FIGURE 5. Arthrobrachus longipilis. Male genitalia. Tegmen and parameres: a: dorsal view; p: parameres; b: lateral view; Median lobe: c: dorsal view, ap: apodeme, pha: phallotreme,; d: ventral view; e: lateral view. Scale 1 mm.