Mischocyttarus omicron Richards 1978
Creators: name: Borges, Rafael Cabral
name: Silveira, Orlando Tobias
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Vespidae
Mischocyttarus
Mischocyttarus omicron

description: Mischocyttarus omicron Richards 1978
(Figs 8, 15, 17, 24)
Mischocyttarus (Monacanthocnemis) omicron Richards, 1978: 372. Holotype ♀, Brazil, Mato Grosso, 23.iii.1968 O.W. Rich- ards (NHM); examined
Mischocyttarus (Monacanthocnemis) omicron Richards: Colomo & Berta 2005: 81
Diagnosis. Female. Fore wing length 11–12 mm. Apex of clypeus weakly but noticeably bidentate; humeral lobes large and roughly quadrangular, rather detached from pronotal profile as seen from above (Fig. 24), humeral surface just behind with an elongate shallow concavity; propodeal median furrow linear and straight, rather deep, with an anterior median low keel; propodeal valve high, with lamella narrow throughout; first metasomal segment short for this group (Fig. 8), length less than [mesoscutum + scutellum + metanotum], but narrow and linear basally, with sides diverging only after spiracles; mesoscutum sculpture dense, with homogeneous aspect, puncture diameter varying rather continuously between relatively narrow limits, interstices rather dull; overall color yellow; dark mark on vertex wide, reaching eyes.
Redescription. Female. Length of fore wing 11–12 mm; head distinctly higher than wide in frontal view (Fig. 15); FHH/IntOW 1.16; clypeus clearly higher than wide H/WCLP 1.19; ventral margin distinctly angular, apex rather wide and slightly bidentate; malar space very narrow; tentorial pit much closer to eye margin than to antennal socket; antennal scape moderately elongated, L/Wesc 2.71; posterior occeli less widely separated than in most species of the group, POL/OOL 1.25; occipital carina well developed, distinct in lateral view and ending fairly below level of ocular sinus; gena considerably narrower than upper lobe of the eye; pronotum without lateral fovea; anterior margin with lamella raised and reflexed especially on center, with lateral profile as a loop reaching more than 180 degrees; region immediately behind the lamella without secondary margin; humeral angle well developed WCAR/WMS 1.05; pronotal carina high, not distinctly lowered at center, but forming large rather quadrate humeral lobes (Fig. 24) with slightly reflexed extremities, area just behind lobes with an elongate shallow concavity; mesoscutum as long as wide, L/WMS 1.0; fore wing very elongated, LDIS/HMP 2.48; hind tarsi with asymmetric claws, inner claw longer with apex uniformly rounded, but not enlarged or spoon-shaped; propodeal median furrow linear, narrow and deep, with a short keel on its anterior 2/3; propodeal valve very high and poorly expanded backward, lamella narrow with rounded margin; first metasomal segment relatively short (Fig. 8), LSI/HMP 1.15; L/WSI 3.54, apex only 1.66 × wider than basal petiole, sides diverging after spiracles, these only moderately prominent.
Sculpture. Moderately strong and conspicuous. Disk of clypeus with weak medium-sized punctures and nearly indistinguishable micropunctures, area close to ventral margin and mandibles smooth, with medium-sized shallow punctures; upper interantennal area, frons and vertex with close dense punctures of generally small diameter, with still smaller punctures surrounding ocelli; mesoscutum sculpture dense, with homogeneous aspect, puncture diameter varying continuously between rather narrow limits (0.04–0.08mm), interstices rather dull, area close to margins with smaller punctures; humeral region similar to mesoscutum, diameter slightly larger; mesopleuron with rather shallow punctures of two distinct size-classes, neither large, nor dense, interstices reticulate and shining; metapleuron similar to mesopleuron, but with sparser punctures; propodeum with medium-sized not very dense punctures near anterior margin, interstices perceptible and shining, central area with large and sparser punctures, integument more shining.
Vestiture. Eyes with very short inconspicuous hairs; head, thorax and mesosoma with conspicuous appressed or decumbent hairs; longer and stouter whitish hairs on lower portion of clypeus, frons, vertex, pronotum and mesopleuron; those on mesoscutum a little shorter; hairs on metapleuron, and propodeum more erect, finer and longer; metasomal sternum 1 distinctly polished with long fine erect hairs; most of tergum 1 and remaining metasomal segments covered by decumbent short hairs; legs generally with conspicuous appressed hairs; femora and tarsi with sparse stout short hairs.
Color. Yellow. Antennal scape and pedicel, disk or metasomal terga 2–6, light orange testaceous; antennal flagellum; area surrounding foraminal concavity; part of anterior face of pronotum; posterior lateral areas of mesoscutum; mark on tegula; subalar area; margins and sulci of mesopleuron; ventral angle of lower metapleural plate; area along lateral margin of propodeum; elongated marks or areas on posterior face of hind coxa, mid and hind trochanters, femora, tibiae, and tarsi; metasomal tergum 1, testaceous to light brown; large triangular area on vertex connecting at sides to eyes and by a posterior median short arm to a wide occipital mark which also connects to eyes (letting two triangular yellow spots on vertex); anterior face of pronotum, large humeral mark, central stripe and anterior region of mesoscutum, most of scutellum and metanotum posteriorly, wide anterior area (extending backwards at sides) and median stripe on propodeum (letting two elongated submedian yellow spots), dark brown to black; wings hyaline with brown veins.
Male. Unknown.
Nest. Richards (1978) described the nest of this species as having a whitish carton, with a flattened 5.0 mm pedicel attached at a corner made by three adjacent cells. It seems to resemble the nest of M. filiformis. Both nests mentioned by Richards (1978) were attached to adaxial surfaces of leaves of shrubs about 1 meter above the ground. The nests were in areas of open vegetation (field and road margin).
Geographic distribution. BRAZIL: Pará *: Serra dos Carajás; Mato Grosso: Ribeirão Cascalheira. BOLIVIA: Beni: Guayaramerim. (see Fig. 34)
Remarks. The known geographic distribution of this species is considerably broadened in this work, with the addition of a record from southeastern Pará state, in Brazil (Fig. 34). The collecting points suggest a distribution along the southern border of the Amazon biome, in transitional areas to Cerrado. Specimens from all areas are similar and may be promptly distinguished from other species in this group by their larger size (fore wing length 12 mm).
Examined material. BOLIVIA: Beni: Guayaramerim, ♀ (PARATYPE) 10.v.1954 (W. Foster) (IFML). Other material. BRAZIL: Pará: Serra dos Carajás, Serra Norte, Fofoca, ♀, 16.ix.1985 (M.F. Torres) (MPEG).
description: Published as part of Borges, Rafael Cabral & Silveira, Orlando Tobias, 2019, Revision of the species-group of Mischocyttarus (Omega) filiformis (de Saussure 1854), with description of three new species (Hymenoptera, Vespidae), pp. 545-564 in Zootaxa 4657 (3) on pages 556-558, DOI: 10.11646/zootaxa.4657.3.7, http://zenodo.org/record/3998493