Mischocyttarus ryani 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 : 166-167

Mischocyttarus ryani Silveira sp. nov.

( Figs. 1 , 11D , 12F and 14A–C )

Mischocyttarus punctatus : Richards, 1978: 371; Garcete-Barrett, 1999: 27 (misidentification)

Holotype: female, Brazil, Bahia, Lençóis , 6/iv/2010, R. Funch ( MPEG).

Diagnosis. Wing length 8.0 mm; clypeus most often a little wider than high, ratio H/WCL 0.96–1.06; first metasomal segment considerably elongated but not actually very slender, LSI/HMP 1.42–1.50, with the apex 2.0–2.22 times wider than the basal petiole; punctures on mesoscutum with diameter grading rather continuously from ca. 0.02 to 0.05 mm; pronotal carina considerably lobated at sides, with concave profile; reddish areas on pronotum of a darker tone; propodeal marks very large and lung-shaped; first metasomal sternum yellow from base to apex; male antennal article 13 rather short, but a little more than three times (3.2) longer than broad, about 0.7 times as long as 11+12.

Description. Female: length of fore wing 8.0 mm. Head nearly as high as wide in frontal view; clypeus often wider than high, ratio H/WCL 0.96–1.06, 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 well developed, distinct in lateral view and ending fairly below the level of ocular sinus and outwards in relation to margin of pre-foraminal concavity; 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 distinct lobe, pronotal carina moderately high at sides, lamella measuring from 0.12 to 0.15 mm, total width of carina ( WCAR) 1.13 to 1.18 times larger than that of mesoscutum; mesoscutum a fraction longer than wide, L/WMS ca. 1.02–1.06. Fore wing well-elongated, LDIS /HMP ca. 2.14–2.19. Inner claw of hind tarsus with the apex uniformly rounded, but not enlarged or spoon-shaped. Propodeum with median furrow relatively wide 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 but not actually very slender ( Fig. 1 ), LSI/HMP 1.42–1.50, with the apex 2.0–2.22 times wider than the basal petiole; spiracles moderately prominent.

Sculpture: moderately strong and conspicuous. Disk of clypeus with weak medium-sized punctures and well distinguishable micropunctures, area close to the ventral margin finely reticulate with sparse punctures, smooth but not really shining; upper interantennal area and frons with puncture diameter variable, small punctures larger and more easily distinguishable. Mesoscutum sculpture with disordered aspect, puncture diameter grading rather continuously from ca. 0.02 to 0.05 mm ( Fig. 11D ); mesopleuron sculpture with smaller punctures finer; propodeum with larger punctures strong but more sparse, central area around median furrow with shallow punctures; integument in general shining.

Vestiture: eyes bare; head and mesosoma with very conspicuous appressed or decumbent pilosity; longer and stouter hairs on clypeus, frons and mesoscutum, those on pleura 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. 12F ). Antenna above, most of legs; discal area of metasomal segments, dark brown. Inner lateral and ventral aspects of antennal scape; ventral aspect of flagellum especially distally, light brown. Mandible teeth and margins; posterior region of head, extensive lateral areas on pronotum; anterior part of mesepisternal plate; lateral anterior and posterior areas on mesopleuron; extensive median areas on mesosternun; most of metapleuron and anterior lateral area of propodeum; extensive areas on anterior surface of legs, reddish brown. Most of mandible and clypeus (around a central diffuse brown mark); inner and outer orbits, moderately broad supra-antennal “V-shaped” mark; band encircling anterior region of pronotum (over carina and descending on sides), weak strip along posterior margin and very narrowly on postero-lateral margin, along pretegular carina; posterior mark on mesepisternal plate; posterior ventral mark on mesopleuron; articular region of mesopleuron; narrow faint posterior streak on upper metapleural plate; inner posterior mark on tegula (outer area amber-like, translucent); scutellum almost entirely, with very small axillar spot; most of metanotum anteriorly; two large-sized (lung-shaped) 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; spot on dorsum of first and fifth segments of fore tarsus; extensive parts of mid coxa especially laterally; 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; apical spot on hind tibia; elongate basal window-like mark and distal marginal band on metasomal tergum I, extending forward at sides up to a point fairly anterior to the spiracle; distal and lateral margins of terga II to VI; most of sternum I from base to distal expanded region; distal margin of sterna II to VI, broadening medially, yellow. Wings hyaline with brown veins.

Male. Apart from sexually dimorphic characters, the male of M. ryani sp. n. is very similar to the female. There is a larger extent of yellow on the mesosternum, and black areas are better developed on humeral region and mesopleuron, with a sharper contrast between black and lighter yellow or brown marks on thorax and head as well. Antennal article 13 is rather short, but relatively slen- der, a little more than three times (3.2) longer than broad, about 0.7 times as long as 11 + 12.

Nest. Several colonies of M. ryani sp. nov. were observed by the first author in Lençóis, Bahia State (see Figs. 14A–C ). Most were found at a single site, with nests attached to various natural or artificial substrates associated with a human habitation (i.e., attached to vines in a garden terrace, iron wires under a marquise, etc.), and some had been active for a relatively long period of time (more than six months; R. and L. Funch, personal communication). The largest of these nests had 26 cells, and was ca. 40 cm long. Completed cells of these nests were ca. 15 mm long and 3.5 mm wide at their distal rim, being made from gray wood pulp. Attachment of the basal cell to the substrate always involved a broad pedicel-like structure.

Distribution: Brazil (BA, MG); Paraguay (Concepción, Amambay).

Etymology: the specific epithet is homage to first author’s nephew Ryan, a very smart little boy who shared his home with colonies of this new species in Lençóis, Bahia, in the Chapada Diamantina.

Remarks. This species is morphologically very close to M. punctatus , but can be distinguished by the slender first metasomal segment (compare Figs. 1 and 2 ), the slightly more-developed humeral lobes of the pronotal carina, and minor differences in the color of the mesosoma. A very interesting aspect of individual behavior of M. ryani sp. nov. is the way the wasps occasionally perch on their nests with their bodies raised on their mid and hind legs, and apparently using also the tip of the metasoma as supporting element ( Fig. 14B and C ).This apparently correlates with nest architecture, as we have observed similar behavior in colonies of species of subgenus Megacanthopus and also of M. (Phi) suzannae Silveira (see Silveira, 2013: 185; Fig. 6A ), which construct very narrow and elongated nests that look like thin, dry twigs (compare Figs.14B–C and D ).The posture of the wasps on these nests may aid in altering the colony’s silhouette in the context of nesting amidst sparse vegetation.

Examined material (Paratypes): Brazil: Minas Gerais, 1 female, Parque Rio Doce , 13/i/2010, Souza, M., Ladeira, T ., Ferreira, M. & Pires, E. ( MPEG); Bahia, Lençóis, 1 female, 1 male, Hotel Fazenda Guaxo , 5/v/2000, G. Melo ( UFPR), 2 males, 11/iii/2011, Silveira, O. T. ( MPEG); Paraguay: Concepción, 1 female, Cororô, 26/ii/1996, Amambay, 3 females, Bella Vista Norte, 23/ii/1999, B. Garcete ( INBP) .

Figures

Figs. 1–10. Schematic drawings showing proportions and measurements of body parts. 1–6: first metasomal segment in dorsal view respectively of: (1) Mischocyttarus ryani sp. nov.; (2) M. punctatus; (3) M. anchicaya sp. nov.; (4) M. rodriguesi sp. nov.; (5) M. caxiuana sp. nov.; (6) M. verissimoi sp. nov. (length =2.78 mm); (7) head, frontal; (8) pronotum and mesoscutum, dorsal; (9) mesosoma, lateral; (10) left anterior wing. FHH: height of head; INTOW: distance between eyes at ocular sinus; HCLP, WCLP: height and width of clypeus; WCAR: width of pronotal carina; LMS, WMS: length and width of mesoscutum; HMP: height of mesopleuron; LDIS: length of discal cell of fore wing; LSI,WSI:length and apical width of first metasomal segment.

Fig. 11. (A–H) Partial halves of anterior mesosoma to show pronotal carina and mesoscutal sculpture (scale as in B):(A) Mischocyttarus rodriguesi sp. nov.; (B) M.caxiuana sp. nov.; (C) M. punctatus; (D) M. ryani sp. nov.; (E) M. tayrona sp. nov.; (F) M. anchicaya sp. nov.; (G) M. verissimoi sp. nov.; (H) M. vaqueroi. (I–L) Detail of mesoscutal sculpture (scale bar= 0.1mm): (I) M. anchicaya sp. nov.; (J) M. ryani sp. nov.; (K) M. rodriguesi sp. nov.; (L) M. caxiuana sp. nov. (M–N) Posterior view of head showing pre-foraminal region and occipital carina (scale as in N): (M) M. vaqueroi; (N) M. caxiuana sp. nov.

Fig. 12. General lateral views of holotype females of: (A) Mischocyttarus tayrona sp. nov.; (B) M.anchicaya sp. nov.; (C) M. caxiuana sp. nov.; (D) M. verissimoi sp. nov.; (E) M. rodriguesi sp. nov.; (F) M. ryani sp. nov.

Fig. 14. (A) Large colony (ca. 40 cm) of Mischocyttarus ryani sp. nov. (Lençóis, BA); (B and C) details of other two colonies of M. ryani sp. nov. showing individuals raising their bodies on mid and hind legs (same place); (D) mature inflorescence of a vine wherein colonies of M. ryani sp. n. were also found (same place); (E) small colony (nest A) with individual female of M. rodriguesi sp. nov., hanging from a Cuscuta trichostyla filiform stem in deep Amazonian rainforest (Caxiuanã, PA); (F) small colony with three females on a forked nest of M. vaqueroi, hanging from a suspense root, in Caxiuanã (PA).