Xanthosomnium, 2002

Sime, Karen R. & Wahl, David B., 2002, The cladistics and biology of the Callajoppa genus-group (Hymenoptera: Ichneumonidae, Ichneumoninae), Zoological Journal of the Linnean Society 134 (1), pp. 1-56 : 37

XANTHOSOMNIUM WAHL & SIME , GEN. N.

Type-species. Xanthosomnium froesei sp. n.

Description. Flagellum of female lanceolate, with flagellomere 3 about 1.8¥ as long as wide; flagellum of male unknown. Clypeus flat and wide, apicolateral margin forming an angle of approximately 40°, punctures evenly distributed, apical 0.3 thinned, apical margin straight and without median projection. Mandible long and evenly tapered to apex, ventral tooth turned under dorsal tooth. Supra-antennal area without median paired ridges or denticles. Vertex with posterior section about as long as ocellar triangle, gently sloping to occipital carina. Gena swollen in dorsal view. Juncture of hypostomal and occipital carinae separated from mandible by about 0.5¥ basal mandibular width. Occipital carina with ventral region above mandible not produced as a low flange.

Pronotal flange low and with posterior face concave. Epicnemial carina dorsally complete. Scutellum moderately convex; lateral carinae absent. Central convexity of metanotum not widened and lateral depressions not reduced. Base of propodeum rising steeply and abruptly. Areola completely filled-in, appearing as polished boss. Anterior transverse carina absent; posterior transverse carina weak but present; lateral longitudinal carinae weak but complete; median longitudinal carinae absent basad anterior transverse carina, present apicad anterior transverse carina. First lateral area with regularly distributed punctures; second lateral area weakly rugosopunctate. Metapleuron rugosopunctate. Juxtacoxal carina absent. Propodeal lateral profile steeply sloping. Scopa absent. Cell 1 + 2Rs of fore wing petiolate, vein 2/Rs <3r-m, vein 2m-cu interception apicad midpoint of posterior margin (vein 2/M about 2.1¥ as long as vein 3/M).

MS 1 in lateral view with petiole flattened, postpetiole convex; sclerotized anterior portion of S1 about 1.5¥ as long as distance from posterior margin of anterior portion to apex of T1; petiole basally without dorsal or lateral bulges; postpetiole without basal convexity, median longitudinal carina absent, median field absent, punctures large and scattered. Ventral margin of T2 simple. T2-4 without longitudinal rugae. T2-4 evenly convex, with normal punctures separated by 0.5–1.0x their diameter. T2-5 not basally constricted and without dorsolateral ridges. S2 divided, S3-5 entire. Apex of female metasoma with T7-8 projecting well beyond apex of T6; amblypygous

Autapomorphies. Apical 0.3 of clypeus thinned (#6–1); ventral mandibular tooth turned under (#12–1); basal area and areola confluent, anterior transverse carina absent (#26–1); postpetiole of MS1 without median field (#47–1).

Etymology. The genus is named after the musical group Tangerine Dream, the choice of discriminating ichneumonologists. From the Greek xanthos, yellow or yellowish-red (the closest equivalent to ‘tangerine’ in a classical language) and the Latin somnium, dream. The gender is neuter.

Species and distribution. There is one species, Xanthosomnium froesei , found in Costa Rica.

Biology. The holotype of X. froesei was reared as a larval-pupal parasitoid of the sphingid Cautethia spuria (see holotype data, above; ‘98-SRNP-3514’ [AEIC]). The host was collected as a penultimate instar feeding on an unidentified species of Chiococca (Rubiaceae) . The locality is at the upper elevational limit of lowland dry forest below Cerro Pedregal, in Area de Conservación Guanacaste, Costa Rica. Although over 500 Sphingidae of 17 species have been reared within one kilometer of this site, no other specimens of X. froesei have been encountered (D. Janzen, pers. comm.).