Acorystus circumflexus Scherrer et Santos, sp. nov.
Creators: name: Scherrer, Marcus V.
name: Santos, Bernardo F.
name: Aguiar, Alexandre P.
Publisher: name: Zenodo
Year: 2010
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Ichneumonidae
Acorystus
Acorystus circumflexus

description: Acorystus circumflexus Scherrer et Santos, sp. nov.
(Figs 1, 2, 8–11, 14)
Description. Ψ. Fore wing 7.05 mm. Head (Figs 1, 2, 8, 9): antenna with 30 flagellomeres; clypeus evenly convex, as punctate and pilose as remainder of head; CWH 1.56; CWW 1.60; MLW 1.26; MWW 0.58; mandible moderately long, apex thin, ventral margin sharp, expanded into perpendicular flange with 0.5 of mandible apex width; ventral tooth about 0.5 as long as dorsal tooth; supra-antennal horn conical, with about 0.5 of pedicel length; supra-antennal area with distinct, irregular, rugose swelling from horn until ocellar triangle, centrally with slight depression as wide as horn base; occipital carina meeting hypostomal carina near mandible base, forming high, sharp flange next to mandible, making a subcircular deep depression between gena and occipital carina flange with about 0.8 as wide of mandible base width; MSM 0.71.
Mesosoma (Figs 1, 2, 10): pronotum with high carina bordering collar, posterior margin with weak and short wrinkles, dorsal margin moderately swollen; mesoscutum with sparse, moderately strong punctures, at border with lateral flange behind tegula; notaulus strongly impressed; lateral carina of scutellum high, sharp, reaching 0.3 of scutellum; epicnemial carina restricted to ventral 0.5 of mesopleuron, almost straight; mesopleuron anterior margin with short, coarse transversal wrinkles; sternaulus strongly impressed, anterior half wrinkled, posterior half shallow, almost indistinct; mesopleural suture with strong transversal wrinkles; metapleuron with long hairs, with very short, rather shallow punctures, separated from each other by about 3.0x their own diameter; pleural carina absent. Propodeum: limit between anterior margin and transverse furrow at base of propodeum centrally indistinct; spiracle elliptical, SWL 2.33; anterior transverse carina centrally arched forwards, area behind it with very small and shallow punctures separated from each other by about 4.0–6.0x their own diameter. Legs: pre-apical tarsomeres weakly bilobed, lobes short, about equal size; FLW 5.21. Wings: fore wing veins 2+3Rs and 1m-cu perfectly continuous with each other; vein 1M+Rs slightly sinuous; crossvein 1cu-a moderately convex, forming slightly acute angle with M+Cu, opposite to vein 1M+Rs; vein 2-Cu 0.54 as long as crossvein 2cu-a; APH 0.30, AWH 2.67; vein 3-M shorter than 2-M; hind wing vein Cua forming obtuse angle with vein 1M; HW1C 1.27; vein 1Rsb entirely tubular; veins 1Rsa and 1Rsb weakly angled; vein Cub slightly sinuous, reaching about 0.8 of distance to wing margin; vein 2-1A reaching about 0.5 of distance to wing margin.
Metasoma (Figs 1, 2, 10, 11): T1LW 3.48, T1WW 1.96, spiracle of first tergite at basal 0.6, almost indistinctly prominent; T2LW 2.16, T2WW 2.22; thyridium almost circular; OST 0.89; dorsal valve of ovipositor with nodus and notch very weak.
Color: Head black; mesosoma orangish; metasoma from deep orange to yellow. Head: black; scape dorsally dark brown, ventrally orange (139,128,51); pedicel and flagellum dark brown, except flagellomeres 5–17 and most of 4 and 18, white; orbital band absent; supra-clypeal area centrally, mandible except apex and medial part of malar space, orangish (221,202,144); clypeus and mouth parts whitish (221,202,144); apex of mandible dark brown. Mesosoma: dorsally orange (208,156,088), ventrally yellowish (235,204,111); propleuron and collar orangish; wings hyaline; legs orange, fore leg lighter; hind tibia basally orangish, turning to pale yellow towards apex; hind tarsomeres 1–4, basal half of hind apical tarsomere whitish; apical tarsomere of middle leg and apical half of apical tarsomere of hind leg, dark brown. Metasoma: T1 dark orange; T2 basally dark brown (132,094,063), medially deep orange, apically with yellowish stripe (224,180,087); T3–4 basally brownish, apically bright yellow (236,210,121); T5–8 yellowish, centrally darker; ovipositor brown, sheath dark brown, laterally with longitudinal white band.
Male. Unknown.
Comments. Can be separated from A. fulvus by having the head black with whitish marks (vs. head orange, ferruginous near ocelli); propodeum with very short and shallow punctures that are spaced by about 4.0–6.0x their diameter (vs. large punctures separated by about 1.3x their diameter); and propodeum not wrinkled (vs. with coarse wrinkles). Isolated from A. albicornis by the female flagellum with white band covering about 15 flagellomeres (vs. about 5); supra-antennal area with black central horn (vs. white), with longitudinal swelling more pronounced and rugose (vs. very weak, only slightly rugose); orbital band absent (vs. present at supra-clypeal and supraantennal areas); sternaulus with anterior 0.5 wrinkled (vs. with very weak wrinkles at anterior 0.3); propodeum with anterior transverse carina centrally arched forwards (vs. almost straight); propodeum and metapleuron with denser punctures that are spaced by about 3.0–6.0x their own diameter at propodeum and by 3.0x at metapleuron (vs. with more sparse punctures, spaced by about 7.0–10.0x their diameter at propodeum and by 5.0x at metapleuron); vein Cub irregular (vs. straight); crossvein 1cu-a convex, ending opposite to vein 1M+Rs (vs. forming slightly acute angle with M+Cu, basad of 1M+Rs by about 0.15 of its own length); pleural carina entirely absent (vs. very weak, with short transverse wrinkles).
Etymology. From the Latin circumflexus, meaning “arched”; in reference to the arched central portion of the anterior carina of propodeum.
Material examined. Holotype Ψ (MPEG) from Brazil, PA, Melgaço, Floresta Nacional de Caxiuanã, Estação Científica Ferreira Pena, Trilha, 22–25.XI.2003, yellow pans, APAguiar & JDias, P05147 [field point]. Fore tarsomeres 3–5 missing, otherwise in good shape.
Distribution. Amazon Basin, Brazil. Known only from the Floresta Nacional de Caxiuanã (2º4’54”S 51º51’5”W) (Fig. 14).
description: Published as part of Scherrer, Marcus V., Santos, Bernardo F. & Aguiar, Alexandre P., 2010, Generic redefinition, key and two new species of Acorystus To w ne s (Hymenoptera: Ichneumonidae: Cryptinae), pp. 28-38 in Zootaxa 2721 on pages 32-37, DOI: 10.5281/zenodo.199900