Mischocyttarus caxiuana Silveira, 2015

Silveira, Orlando Tobias, Silva, Suzanna de Sousa & Felizardo, Sherlem Patricia de Seixas, 2015, Notes on social wasps of the group of Mischocyttarus (Omega) punctatus (Ducke), with description of six new species (Hymenoptera, Vespidae, Polistinae), Revista Brasileira de Entomologia 59 (3), pp. 154-168 : 162-163

publication ID	https://doi.org/ 10.1016/j.rbe.2015.07.006
persistent identifier	https://treatment.plazi.org/id/0D340C17-FFB3-6E21-FCDF-F983FA7BF996
treatment provided by	Felipe
scientific name	Mischocyttarus caxiuana Silveira
status	sp. nov.

Treatment

Mischocyttarus caxiuana Silveira sp. nov.

( Figs. 5 View Figs , 11B, L, N View Fig and 12C View Fig )

Mischocyttarus (Monacanthocnemis) punctatus View in CoL : Silva and Silveira, 2009: 320 (misidentification)

Holotype:female, Brazil, Pará , Melgaço, Caxiuanã, 4/iii/2006, S.S. Silva and J. Dias ( MPEG).

Diagnosis. Female: wing length 6.5–7.5 mm; clypeus distinctly higher than wide; first metasomal segment moderately elongated, LSI/HMP 1.50–1.54; occipital carina less developed in lateral view, fading down at the level of ocular sinus, and (from behind) positioned more inwards in a direction that is coincident with the lateral margin of pre-foraminal concavity situated just below; yellow marks on head and mesosoma very extensive, including most of median ventral areas; pronotum at sides largely reddish; metasomal segments light testaceous with distal yellow bands.

Description. Female: length of fore wing 6.5–7.5 mm. Head nearly as high as wide in frontal view; clypeus distinctly higher than wide, H/WCL 1.09–1.11, apex narrowly truncate; malar space nearly obsolete; tentorial pit much closer to eye margin than to antennal socket; ocelli as in an equilateral triangle, narrowly separated from eyes, POL/OOL about 1.0; occipital carina less developed at sides in lateral view, fading down at the level of ocular sinus, and (from behind) positioned more inwards in a direction that is coincident with the lateral margin of pre-foraminal concavity situated just below ( Fig. 11N View Fig ); gena considerably narrower than the upper lobe of the eye. Pronotum without a lateral fovea, central part of the anterior margin of pronotum with the lamella raised and strongly reflexed, with contour profile reaching more than 180 degrees; region immediately behind the lamella without secondary margin; humeral angle well developed, produced into a strong lobe, pronotal carina very high at sides, lamella very wide measuring ca. 0.19 mm, total width of carina ( WCAR) about 1.16 times larger than that of mesoscutum; mesoscutum a fraction longer than wide, L/WMS ca. 1.10. Fore wing well-elongated, LDIS /HMP ca. 2.0. Inner claw of hind tarsus with the apex uniformly rounded, but not enlarged or spoon-shaped. Propodeum with median furrow narrow and shallow, developed on 4/5 of the length of propodeal dorsum, propodeal valve strongly expanded backward, with outline more semioval than triangular. First metasomal segment moderately elongated ( Figs. 5 View Figs and 12C View Fig ), LSI/HMP 1.50–1.54, with the apex 2.05–2.27 times wider than the basal petiole; spiracles weakly prominent.

Sculpture: moderately strong and conspicuous, largely covered by the abundant appressed pubescence. Disk of clypeus with medium-sized punctures and nearly indistinguishable micropunctures, area close to the ventral margin finely reticulate with sparse larger punctures, shining; upper interantennal area and frons with puncture diameter variable, small punctures larger and more easily distinguishable; Mesoscutum sculpture with punctures of two size-classes, the larger ones very distinct measuring ca. 0.06 mm or more, the smaller about 0.02 mm or a little larger in front, but any way being very different in size from the larger ones ( Fig.11B and L View Fig ); mesopleuron and propodeum sculpture similar to that of mesoscutum, but with small-sized punctures still finer; propodeum central area around median furrow smooth, unpunctured; integument in general very shining.

Vestiture: eyes bare; head and mesosoma with very conspicuous whitish appressed or decumbent pilosity; longer and stouter hairs on clypeus, frons and mesoscutum, those on pleuron and propodeum still longer but finer and more decumbent; metasomal terga with appressed pubescence, and more erect hairs on distal segments; first metasomal sternum with very smooth and shining integument, nearly absolutely glabrous except for rather sparse fine and curved hairs; remaining sterna with appressed pubescence, with longer and more erect hairs on distal segments, besides those of glandular brushes.

Color: black (see Fig. 12C View Fig ). Antenna above (especially proximal articles); posterior and lateral areas on mid and hind coxae; posterior and ventral surfaces of trochanters, femora and tibiae; mid and hind tarsi; ground color of first metasomal tergum and sternum, dark brown. Inner and ventral aspects of antenna (especially distal articles) very light brown. Mandible apical and lateral margins narrowly dark reddish brown. Main surface of mandible teeth; faint narrow spot on clypeus (connected to an interantennal darker mark); posterior region of head medially; posterior lateral area on pronotum; mesopleural areas bordering a large “Yshaped” black mark; area adjacent to mesopleural posterior margin narrowly; median areas on mesosternum; extensive areas on metapleuron and latero-anterior region of propodeum; extensive areas especially on anterior aspect of all femora, trochanters and tibiae; main discal area of metasomal terga and sterna II to VI, light reddish brown. Most of mandible and clypeus (around a central faint mark); inner and outer orbits; narrow supra-antennal concave “V-shaped” mark; gena and posterior lateral aspect of head and estipes of maxilla; band encircling anterior region of pronotum (over carina and descending on sides), widening at ventral corner; strip along posterior margin, very narrowly on postero-lateral margin along pretegular carina; very extensive areas on mesopleuron and mesosternum around dark marks, including a posterior spot on mesepisternal plate; dorsal spot on upper metapleural plate; posterior spot on lower metapleural plate; inner margin of tegula (outer area amber-like, translucent); small mark on base of anterior wing; anterior half of scutellum (divided by a median line), with spots on mesoscutellar crest and axilla; most of metanotum anteriorly with small spot on axilla; two medium sized spots on propodeum; valvular region; most of anterior and lateral surfaces of fore coxa; distal margin of all trochanters narrowly; distal spot on fore femur; dorso-lateral stripe on fore tibia; dorsum of first and fifth segments of fore tarsus; most of anterior surface of mid coxa; two dorsal stripes and one ventral mark on hind coxa; distal mark on mid and hind femora; elongated stripe on dorsal surface and distal spot on mid tibia; basal and apical spots on hind tibia; basal elongate window-like mark and distal marginal band on metasomal tergum I, extending forward at sides up to the spiracle; distal and lateral margins of terga II to VI; distal expanded region of sternum I; distal margin of sterna II to VI, yellow. Wings hyaline with light brown veins.

Male: unknown.

Nest. The only known nest of this species is from Caxiuanã (Nest E, 04/iii/2006: 10 cells + 1 unfinished): a vertical, single-row comb fastened to the substrate by a short thin secretion-made pedicel (in this case, a thin filiform stem of the parasitic plant Cuscuta trichostyla Engelm. , Convolvulaceae ; see Figs. 13A–C View Fig and 14D View Fig for the same substrate being used by other species). A blackish wasp-secretion covers the plant stem near the pedicel attachment point. Complete cells measure ca. 13 mm in length and 3 mm in width at their distal rim and they are made with light gray wood pulp. One cell is still capped and three others show the remains of pupal caps, made of translucent secretion without any wood pulp fragments. Each one of the more distal cells is attached though a small stalk-like extension to the wall of the preceding cell, indicating that new cells can be added to the nest before completing the serially preceding cells (see Fig. 13C View Fig ). Each of these connecting stalks (representing the distal 30% of a cell’s length), in fact, consists of just a partial precursory cell-wall constructed on just one side of the cell-chain. The lines demarcating these precursory distal elements can be distinguished in fully constructed cells by careful inspection under a dissecting microscope. Interestingly, the position of the precursory inter-cell connections in this nest specimen alternate between cell sides producing a zigzag profile as described by Richards (1978).

Distribution: Brazil ( PA).

Etymology: the specific epithet refers to “Caxiuanã”, a beautiful and luxuriant rain forest along the lower course of the Anapu River, where the Museu Goeldi maintains a field research station.