Denticulobasis ariken Machado, 2009, sp. nov.

Denticulobasis ariken sp. nov.

Figures 8, 18, 19.

Etymology: Named after the Ariken indian people who inhabited the municipality of Ariquemes, Rondônia, and whose descendants live now scattered throughout the region.

Type specimen: Holotype (Ƥ). BRAZIL, Rondônia State: Rio Pardo and tributaries, ca. 13 Km NW of Fazenda Rancho Grande (62 Km SW of Ariquemes 10º50´S, 63º7´W), 187 m., 5–10/XI/1989, R.W. Garrison leg. (MNRJ).

Description. Female holotype

Head. Labium white, base of mandibles and genae yellowish white, anteclypeus and labrum grey, the latter surrounded by yellowish white. Postclypeus, antefrons, and top of head brown, the latter with rounded pale blue postocular spots.

Thorax. Prothorax: Propleuron and anterior lobe light blue; remaining parts orange yellow. Pterothorax orange yellow with blue stripes on mesepisternum (antehumeral), metepisternum, and metepimeron, the latter occupying entire lateral part of sclerite. Legs yellow. Wings hyaline, venation brown, pterostigma brown surrounded by a yellow line. Px in FW 12, HW 11; R3 arising near Px 6 in FW, and 5 in HW. Anal vein separating from wing margin distally to Ac for a distance equal to ½ of Ac length in FW and ¼ in HW.

Abdomen. S1–2 dorsally dark brown, laterally light blue. S3 dorsally dark brown, dorso-laterally blue, ventrally yellow. S4–6 dorsally dark brown, laterally yellow; S7–8 dorso-laterally yellowish orange, ventrally whitish yellow, S9–10 orange yellow. A black ring occupying distal 1/7 of S3–6.

Structural characters. Hind lobe of prothorax (Fig. 8) with lateral lobes well-developed. Median lobe subrectangular, single-lipped with a longitudinal depression at mid-line. Mesostigmal plate (Fig. 8) with anterior and posterior margins convergent and connected to the one on other side. Mid-dorsal carina with cleft at level of mesepisternal tubercle. Mesepisternal tubercles (Fig. 8) low and mammiliform. Ovipositor reaching to level of tip of cercus (as in Fig. 11). Vulvar plate (Fig. 18) with a short neck and straight distal margin with six denticles of regular size arranged side by side (Fig. 18).

Dimensions (mm). Abdomen 32.10; HW 19.45.

Remarks. General color pattern, and especially presence of a vulvar plate, leaves no doubt that D. ariken is a Denticulobasis. It differs from the females of the other two congeners by the convergent margins of mesostigmal plate and the morphology of vulvar plate with distal border straight (curved in D. dunklei) and denticles arranged regularly side by side (in three groups in D. garrisoni).