Mischocyttarus wagneri (du Buysson 1908)

Silveira, Orlando Tobias, 2019, Taxonomic notes on social wasps of the groups of Mischocyttarus wagneri (Buysson 1908) and M. barbatus Richards 1945 (Hymenoptera, Vespidae, Polistinae), Revista Brasileira de Entomologia 63 (1), pp. 53-72 : 56-59

Mischocyttarus wagneri (du Buysson 1908)

( Figs. 7; 10; 12; 15a; 17 ; 19; 20 )

Megacanthopus wagneri R. du Buysson 1908: 219 . Holotype: female, Brazil, Rio de Janeiro, “Serra dos Órgãos” (Portuguese name of that locality; ca. 1.000 m) (MNHN); [photographs examined].

Mischocyttarus pedunculatus Zikán 1935: 159 , figs. 9–10, 14. Lectotype: female, Brazil, Rio de Janeiro, Itatiaia , ii/1933, J.F. Zikán (MZSP); designated by Richards (1978); [examined]; Synonymy by Richards (1945).

Mischocyttarus pedunculatoides Zikán 1949: 236 . Lectotype: female, Brazil, Rio de Janeiro, Itatiaia , ii/1933, J.F. Zikán (IOC); designated by Richards (1978); [examined]; Synonymy by Richards (1978).

Mischocyttarus wagneri : Richards (1945: 371, 1978: 334); Zikán (1949: 150); Silveira (2008: 517, 541, 546); Souza et al. (2010: 25, 28); Togni et al. (2014: 12, 13).

Mischocyttarus pedunculatus : Zikán (1949: 149, figs. 92–93, 232, 327, 381, 418–419).

Female

Length of fore wing 8–10.5 mm; clypeus wider than high, H/WCLP about 0.93 (min–max: 0.88–0.96), apex narrowly truncate, clypeus not so extensively in contact with eye, free upper part of lateral margin relatively long, a little more than 0.3 times the clypeus height at middle; malar space narrow; tentorial pit a little closer to eye margin than to antennal socket; ocelli as in an equilateral triangle; occiput rounded, carina absent; gena just narrower than the upper lobe of the eye; pronotum with lateral fovea, central part of the anterior margin of pronotum with the lamella wide and rather raised but not reflexed, region immediately behind produced into a secondary margin which is acute and projecting over the lamella ( Figs. 7; 10 ); humeral angle poorly developed, total humeral width nearly equal to that of mesoscutum, sides of the pronotum as seen from above distinctly converging; pronotal carina completely absent at center, poorly salient at sides, not forming true lobes and not at all reflexed, with a very narrow translucent lamellar portion at the extremity, mesoscutum about as long as wide, L/WMS around 1.0, lateral margin adjacent to tegula well demarcated and prominent; fore wing comparatively short for this group, LDIS/HMP nearly always below 2.20 (only one of fifteen specimens above this value) (mean 2.12; min–max: 2.00–2.27); basal inner (posterior side) margin of fore coxa raised and strongly reflexed ( Fig. 12 ); inner claw of hind tarsus with the apex narrowly pointed, but not acute; propodeal dorsal cavity comparatively deep and elongate, almost reaching propodeal anterior margin, propodeal valve rather broadly round, lamellar margin behind not distinctly oblique, not conferring to valve a triangular shape; first segment of metasoma very elongate and slender ( Figs. 19; 20 ), its length always larger than 1.3× height of mesopleuron (mean LSI/HMP 1.39; min–max: 1.34–1.50), and nearly always more than 3.30× width at apex (except in two of 15 examined specimens), about 2.12× wider at apex than at base (min–max: 2.00–2.25), spiracles moderate to distinctly prominent ( Fig. 20 ).

Sculpture: head and mesosoma with rather fine sculpture of granulated aspect; clypeus with minute dense punctation (diameter ca. 0.015 mm), with moderately shining interstices measuring about one puncture diameter, and also with shallow sparser larger punctures (diameter 0.030 –0.037 mm), apical central area very finely reticulate, appearing almost smooth, shining, with a few interspersed large shallow punctures (diameter 0.037–0.44 mm); frons with similarly sized punctures, but deeper and a little more dense; mesopleuron with pattern similar to clypeus, but with the small-sized punctures a little closer; humeral area of pronotum with slightly larger and denser punctures (diameter ca 0.022 mm); mesoscutum with punctures slightly larger and less dense, diameter 0.022 –0.030 mm, interstices mostly of 0.5 puncture diameter); propodeum with punctures a little larger and sparser.

Vestiture: eyes bare; most body parts covered by fine appressed shining pubescence, dense to the point of obscuring the pattern of micropunctures underneath; clypeus with sparser erect longer setae especially near apical margin, shorter erect setae also on frons and vertex, setae on pronotum and mesoscutum strongly decumbent and often not outstanding at all; gena beneath with distinctly longer hairs; propodeum dorsolaterally with very long fine hairs with recurved tip.

Color (see Figs. 19 and 20 ): Black, largely suffused with dark reddish brown (but propodeum dorsum distinctly darker, blackish to black); mandibles pitchy red with a yellow longitudinal mark (sometimes indistinct); antennae with segments 3 and 9–12 reddish (to pale yellowish) beneath (but sometimes indistinct); clypeus (except actual ventral margins, black dorsal sides and large discal red brown spot) [sometimes practically whole clypeus brown, leaving only the ventral marginal area yellow], inner orbits to top of eye, antennal segments 1–2 beneath (sometimes indistinct), small spots above and below antennal sockets (sometimes indistinct), malar space and narrow genal stripe (outer orbit) [often interrupted or absent below], two dots behind ocelli, pronotum ventral corner (near fovea) and tubercle [sometimes indistinct], pronotal carina and hind margin of pronotum, pair of discal streaks on mesoscutum (sometimes evanescent), axillae and scutellum except disk, anterior margin of metanotum, valves and two elongate spots on propodeum, scrobal spot (sometimes very small), spot on upper metapleural plate, hind margin of mesosternum (sometimes only around coxal articulation), apex of fore coxa (sometimes indistinct), one dorsolateral stripe on mid coxa, and two stripes on hind coxa, posterior spot at apex of fore femur (sometimes indistinct), distal spots on mid and hind femora, narrow posterior bands on gastral terga 1–2 (or -4) extending forward at sides (sometimes indistinct), on sterna 2–3 (or -4) [but often indistinct], yellow; tibiae and tarsi brown, hind tarsus articles 2–4 blackish; inner side of hind tibia darker before apical pad which is paler; tegula brown; wings hyaline, venation brown.

Male

Length of fore wing 9.0 mm; mandible with four teeth; clypeus touching eyes, a little wider than high, ventral angle obtuse, apical margin almost rounded; antenna with the scape relatively shorter and wider, ventral surface of the flagellum with tyloids reduced or fragmented, apex of the antenna just rolled, hook like, antennomere 13 about 4–5× longer than wide; clypeus with very conspicuous dense shining pubescence.

Color: similar to female; face below antenna, antenna beneath, proepisternum posteriorly, mesosternum widely, fore and mid coxae ventrally, anterior stripes on all femora, posterior band on metasomal sternum 4, a posterior dot on tegula, yellow.

Variation

The specimens examined of M. wagneri are remarkably homogeneous in color, even when comparing representatives of populations of distantly separated localities from different states, like Minas Gerais and Rio Grande do Sul. The length of the first metasomal segment, while varying to considerable extent, remains always above a certain lower limit (i.e. larger than 1.30× height of mesopleuron), longer than most of the specimens examined of the remaining species in this group (see Fig. 44 ).

Nest

Buysson (1908) did not see the nest of M. wagneri . Only Zikán (1935) described it from Itatiaia (RJ) as the nest of M. pedunculatus , saying... (translated from German) three nests were attached to plant roots hanging from the ground, two nests to dry fern leaves and another one to a rock (creek edge). This species builds its nests preferably on the edges and slopes of roads and landslides, attached to thin plant roots coming off the ground. The nest which was attached to rock was of a light reddish-brown color; that hanging from plant roots was of gray color, with a reddish-brown admixture, and the nest on dry fern was of dark brown color with a gray admixture. What they all have in common is an irregular, wavering shape in which full and half-finished cells succeed each other in rows, irregularly juxtaposed, thus resembling parts of dead plants, or dry ragged leaves, in excellent adaptation to the environment. Especially the two nests attached to ferns achieve this to a great extent – they resemble in shape the small still unfinished nests of ( Mischocyttarus ) declaratus and confusus. The largest (of 17/ii) has 66 cells, arranged as an irregular triangle, with a somewhat eccentric peduncle. Two males and 8 females were found on this nest and subsequently another 4 females and 7 males emerged of the cells until 5/iii. Zikán (1949, fig. 381) also presents a photo of a nest of this species, showing an elongated comb with the irregular profile described above, and it has a very eccentric pedicel.

Fig. 17 presents two views of a nest from Caraguatatuba (São Paulo) which was mentioned in Richards (1978). It has suffered a little damage, but the comb preserves an elongated shape as mentioned in published descriptions.

Distribution

Brazil: Minas Gerais; Rio de Janeiro; São Paulo; Rio Grande do Sul (see Fig. 47 ) .

Remarks

Richards (1978) compared Zikán’s type series to a specimen previously checked with the MNHN Buysson’s type. Photographs of this type-specimen were made available by staff of the MNHN, and are sufficient to confirm that Richards’s concept of this species is correct. Furthermore, M. wagneri is reasonably differentiated by some typical characters, like the very elongated first metasomal segment, and dense whitish pilosity on the face. The synonymy of M. pedunculatoides Zikán 1949 is also undoubtedly correct. All records of this species come from localities in (or very close to) the highlands of the Brazilian “Serra do Mar” or related mountain ranges. Records from Rio Grande do Sul extend the range of this species for nearly 1000 km southward ( Figs. 46–47 ).

Examined material: Brazil. Minas Gerais: Cambuquira , 1 female 12/ix, 1 female xii/1933, J.F. Zikán ( IOC) ; Barroso , 1 female 11/x/2003, 2 females 10/iv/2004, Souza M.M., Nascimento M.A., Silva M. & Silva M.A .; Tiradentes , 1 female 15/iii/2008, Souza M.M., Ladeira T. & Assis N. ( MPEG) ; Rio de Janeiro: Itatiaia, 3 females 3/ii, 550 m Faz. Valparaíso (“zu Bau 5”), 1 female 13/iii, 2 females 17/ii, 1 female 26/iii/1933, 1female 15/v/1934, J. F. Zikán (paralectotypes of M. pedunculatus ; IOC) ; São Paulo: Caraguatatuba ( Res. Flor. 40 m), 4females, 14/vii/1965, Exp. Dep. Zool. ( MZSP) ; Ubatuba , Floresta

O.T. Silveira / Revista Brasileira de Entomologia 63 (2019) 53–72 59

Angelim, 1 female, viii/2007, O. Togni ( UNESP /RC); Rio Grande do Sul: Santa Cruz do Sul, Cinturão verde, 2 females 12/xii/2004, M. Hermes; Venâncio Aires, 1 female 08/vi/2006, A. Somavilla ( MPEG) .

Figures

Figs. 5–18. 5–7: frontal–dorsal view of anterior face of pronotum showing secondary margin (arrow) in M. barbatus (5), M.mixtus (6), M. wagneri (7); 8–10: same structures and species in dorsal view; 11–12: mesial view of fore coxa showing raised basal margin (arrow) in M. mixtus (11), M wagneri (12); 13–14: inner (larger) hind tarsal claw (arrow) in M. mixtus (13, lateral) and M. barbatus (14, ventral); 15: hind tarsus of M. wagneri (a), M. mourei (b), M. proximus (c), M. camanducaia sp. nov. (d), M. declaratus (e); 16–18: nests of M. proximus (16), M. wagneri (17), M. barbatus (18); all scales = 0.50mm, except in Fig.18 (= 10 mm); groups of figs. (5–7), (8–10), (11–12), (13–14) share the same scale.

Figs. 19–26. General dorsal and lateral body views (females; all from Brazil).19–20: M.wagneri (RS, Sta. Cruz do Sul; MPEG);21–22: M.camanducaia sp. nov.(holotype:MG, Camanducaia; MPEG); 23–24: M. proximus (SP, Campos do Jordão; MPEG); 25–26: M. declaratus (MG, Barroso; MPEG); all scales = 1.0mm.

Fig. 44. Scattergram of ratio variables for species of the group of M. wagneri: x axis – LSI HMP (length of first metasomal segment over height of mesopleuron); y axis – LDIS HMP (length of fore wing discal cell over height of mesopleuron); open squares: M. wagneri; pink filled squares: M. mourei; black asterisks: M. proximus; blue filled triangles: M. camanducaia sp. nov.; black filled diamonds: M. declaratus.

Fig. 47. Map detail of southeastern South America (with partial view of some Brazilian states) with species distributions for the M. wagneri group. MG: Minas Gerais, RJ:Rio de Janeiro, SP: São Paulo, PR:Paraná, SC: Santa Catarina, RS: Rio Grande do Sul.

Fig. 46. Partial truncated map for Central and South America with species distributions for the M. barbatus group, and with the pooled distribution of the group of M.wagneri (see next figure for detailed representation of distributions of species of this group).