Acorystus albicornis 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 albicornis

description: Acorystus albicornis Scherrer et Santos, sp. nov.
(Figs 3–7, 14)
Description. Ψ. Fore wing 5.1–5.8 mm. Head (Figs 3–5): antenna with 24–25 flagellomeres; clypeus pronounced, rounded, strongly convex, apex slightly concave; as punctate and pilose as remainder of head; CWH 1.62, CWW 1.62; MLW 1.39, MWW 0.61; mandible moderately long, apex thin, ventral margin sharp, expanded into perpendicular flange with 0.3 of mandible apex width, ventral tooth about 0.5 as long as dorsal tooth; supraantennal horn conical, with about 0.5 of pedicel length; supra-antennal area with pair of very weak sublateral longitudinal swelling from horn until ocellar triangle, this swelling irregular, with slight rugulosities; occipital carina meeting hypostomal carina near mandible base, forming a high, sharp flange next to mandible, making a deep rift between gena and occipital carina flange with about the extension of mandible base width; MSM 0.8.
Mesosoma (Figs 3, 6): pronotum with high carina bordering collar, posterior margin with weak and short wrinkles, dorsal margin moderately swollen; mesoscutum with sparse, thin, shallow punctures, with lateral flange behind tegula; notaulus strongly impressed; lateral carina of scutellum high, sharp, reaching 0.25 of scutellum; epicnemial carina restricted to ventral 0.5 of mesopleuron, almost straight; mesopleuron anterior margin with short, tick transversal wrinkles; sternaulus moderately impressed at anterior 0.5, with very weak wrinkles at anterior 0.3, posterior 0.5 very shallow; mesopleural suture with strong transversal wrinkles; metapleuron with long hairs, with almost indistinct, rather shallow punctures that are separated by about 5.0x their own diameter; pleural carina very weak, with short transverse wrinkles. Propodeum: limit between anterior margin and transverse furrow at base of propodeum centrally indistinct; spiracle elliptical, SWL 2.00; anterior transverse carina almost straight, area behind it smooth, with almost indistinct, rather shallow punctures that are separated by about 7.0–10.0x their own diameter. Legs: pre-apical tarsomeres bilobed, mesal lobe slightly longer than lateral lobe; FLW 5.94. Wings: fore wing vein 2+3Rs and crossvein 1m-cu perfectly continuous with each other; vein 1M+Rs slightly sinuous; crossvein 1cu-a weakly convex, forming slightly acute angle with M+Cu, basad of 1M+Rs by about 0.15 its own length; vein 2-Cu about 0.43 as long as crossvein 2cu-a; APH 0.37, AWH 1.86; veins 3-M and 2-M about same size; hind wing vein Cua forming obtuse angle with vein 1M; HW1C 1.10; vein 1Rsb with constricted diameter during its apical 0.85; veins 1Rsa and 1Rsb almost continuous; vein Cub straight, reaching about 0.8 of distance to wing margin; vein 2-1A reaching about 0.6 of distance to wing margin.
Metasoma (Figs 3, 6, 7): T1LW 4.08, T1WW 1.76, spiracle at basal 0.6, not prominent; T2LW 1.54, T2WW 2.18; thyridium almost circular; OST 0.84; dorsal valve with nodus and notch absent.
Color: Head black; thorax, legs, metasoma yellow. Head: black; scape dorsally brown, ventrally yellow; pedicel and flagellomeres 1–2 dorsally mostly light brown, apical flagellomeres dark brown, except flagellomeres 8–10 and most of 6–7 and 11–12, white; orbital band present only at supra-clypeal and supra-antennal areas; supraclypeal area, clypeus, mandible except apex, mouth parts and medial part of malar space, whitish (207,179,116); supra-antennal horn white; apex of mandible dark brown. Mesosoma: dorsally brownish orange (150,098,050), ventrally yellowish (150,098,050); propleuron and collar whitish; wings hyaline; legs yellowish, fore leg lighter, hind coxa darker; fore and median tarsi centrally brown, median ones darker, most of hind pre-apical tarsomere brown, apical tarsomeres dark brown. Metasoma: ranging from orange in T1-2 (196,134,035) to light yellow (240,219,127) at apical tergites; ovipositor brown, sheath dark brown, with lateral longitudinal white band.
Male. Very similar to female, but differs from it by the following: body more pilose; antenna with 27 flagellomeres; weaker swelling at supra-antennal area; fore wing crossvein 2Cua about 0.5 as long as vein 2cu-a; vein 2-M longer than 3-M; mesopleural fovea very shallow; justacoxal carina indistinct; pleural carina entirely absent; tarsi brown, except by hind tarsomere 1 posterior half, and hind tarsomeres 2–3, white; anterior transverse carina of propodeum centrally slightly arched; spiracle at T1 prominent.
Variation. Body varying from light orange (213, 161, 071) to brownish orange (156, 100, 029); flagellomere 2 sometimes light brown; two specimens with orbital band reaching dorsal area of gena, dorsal margin of pronotum whitish, central lobe of mesoscutum dark brown, lateral margin of mesoscutum posteriorly whitish, thorax ventrally lighter, propodeum with anterior transverse carina very slightly arched forward; posterior half of hind tarsomere 1 and hind tarsomeres 2–3 sometimes whitish; pleural carina sometimes with very weak wrinkles restricted to anterior area; metasomal T1–3 sometimes orangish.
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, rather shallow punctures that are separated by about 7.0– 10.0x their diameter (vs. large punctures that are separated by about 1.3x their diameter); and propodeum not wrinkled (vs. with weak coarse wrinkling). Differs from A. circumflexus by the female flagellum with white band covering about 5 flagellomeres (vs. about 15); supra-antennal area with white central horn (vs. black), with longitudinal swelling very weak, slightly rugose (vs. more pronounced and rugose); orbital band present at supraclypeal and supra-antennal areas (vs. absent); sternaulus with very weak wrinkles at anterior 0.3 (vs. with anterior 0.5 wrinkled); propodeum with anterior transverse carina almost straight (vs. centrally arched forwards); propodeum and metapleuron with more sparse punctures that are separated by about 7.0–10.0x their diameter at propodeum and 5.0x at metapleuron (vs. more dense punctures that are separated by about 4.0–6.0x their diameter at propodeum and 3.0x at metapleuron); vein Cub straight (vs. slightly irregular); crossvein 1cu-a forming slightly acute angle with M+Cu, basad of 1M+Rs by about 0.15 of its own length (vs. convex, ending opposite to vein 1M+Rs); pleural carina very weak, with short transverse wrinkles (vs. absent).
Etymology. From the combination of the Latin albus, meaning “white”, and cornus, meaning “horn”; in reference to the white horn at supra-antennal area.
Material examined. 9 Ψ and 1 ɗ. Holotype Ψ (UFES): BRAZIL, ES, Cariacica, Reserva Biológica de Duas Bocas, Pau Amarelo, 23–25.X.2005, yellow pans, Pt. 18 [field point], APAguiar et al. In good shape. Paratypes (UFES): 1 Ψ from BRAZIL, ES, Cariacica, Reserva Biológica de Duas Bocas, Pau Amarelo, 23–25.X.2005, yellow pans, Pt. 16, APAguiar et al.; 1 Ψ, same data except Pt. 17; 1 Ψ, same data except Pt. 18; 1 Ψ and 1 ɗ, same data except 27–29.X.2005, Pt. 16; 1 Ψ, same data except Pt. 17; 1 Ψ, same data except Pt. 18; 1 Ψ from BRAZIL, ES, Santa Teresa, Estação Biológica Santa Lúcia, 09–13.V.2006, yellow pans, MTavares, CAzevedo et al.; 1 Ψ, same data, except 09.V.2006.
Distribution. Atlantic Forest, Brazil, ES. Recorded from two close localities at Reserva Biológica de Duas Bocas (20º16’21”S 40º28’40”W) and Estação Ecológica Santa Lúcia (19º57’55”S 40º32’25”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 31-32, DOI: 10.5281/zenodo.199900