Trimeria robusta, Hermes, Marcel G. & Melo, Gabriel A. R., 2006

Hermes, Marcel G. & Melo, Gabriel A. R., 2006, Two new species of Trimeria de Saussure from Brazil, with biological notes and a key to the Brazilian taxa (Hymenoptera, Vespidae, Masarinae), Zootaxa 1155, pp. 61-68 : 63-66

Trimeria robusta new species

( Figs. 1, 2, 4, 5, 6, 7 , 10, 13, 14, 15 )

Diagnosis and comments

Clypeus nearly as wide as long, with a distinct shiny apical margin; labrum distinctly narrower than apex of clypeus; angle between anterior and lateral portions of mesepisternum rounded, pleural carina absent; disc of scutellum weakly convex, its median line slightly raised posteriorly; tegula broadly rounded posteriorly; midtibia with two unequal apical spurs; body punctures shallow and sparse.

Trimeria robusta n. sp. is the largest species in the genus, being readily distinguishable from the remaining Brazilian species of Trimeria by the characters mentioned in the key. It is probably a basal species within the group because of the unmodified female gena and the two spurs on the mid tibia. It is of special note that the male has the apical flagellomere modified into a hook, a feature shared with the male of the Chilean desert species T. atacama (Fritz) .

Description

HOLOTYPE FEMALE. Coloration. Integument mostly black, with yellow markings as follows: stripe on inner orbit of compound eye, widely interrupted medially at the level of antennal socket; narrow and short stripe on upper gena; stripe on pronotum adjacent to dorsal pronotal carina and a lateral stripe adjacent to margin of mesoscutum; small spots near lateral margin of mesoscutum; tegula basally and apically; spot on basal sclerite of fore wing; elongate spot on axilla; stripe on posterior margin of scutellum; irregular mark extending from dorsal face to lateral angle of propodeum; small marks on base of all tibiae; irregular stripes on apex of T1 and T3­T5; small spots on latero­apical margins of S3. Labrum dark brown; tibiae and tarsi dark reddish brown; wing veins dark brown, membrane dark brown infumate.

Structure. Gena flat, not excavated; lateral portion of occipital carina not raised into a translucent lamella and not reaching base of mandible; eyes with sparse, conspicuous short hairs; clypeus nearly as wide as long, with a distinct shiny apical margin; labrum distinctly narrower than apex of clypeus; punctures of head almost obsolete, evident only on vertex; head covered by apressed and short pale yellow pubescence; pronotum, mesopleuron, mesoscutum and scutellum coarsely punctate; notauli complete, weakly indicated; angle between anterior and lateral portions of mesepisternum rounded, pleural carina absent; disc of scutellum weakly convex, its median line slightly raised posteriorly; scutellum produced backwards into a sharp lamella; tegula broadly rounded posteriorly; lateral processes of propodeum weakly developed; posterior surface of propodeum at most with few shallow punctures, without striae; midtibia with two unequal apical spurs; T1 and T2 with weak and shallow punctures, which become weaker and shallower on the remaining terga.

Measurements (in mm): fore wing length, from middle of tegula to apex, 8.0; approximate body length, 10.0; head maximum width, 2.72; head height, from apex of clypeus to vertex, 2.56.

PARATYPE MALE. Color similar to female, except for additional and more extensive yellow markings as follows: apical half of clypeus, extending basally on sides and mid portion; mandibles entirely; complete stripe on inner orbit of compound eye; large medial spots on frons immediately above level of antennal sockets; stripe on inner surface of scape; large spot on mesepisternum; irregular mark on latero­apical margin of mesoscutum; spots on mesoscutum between notauli; legs extensively; irregular stripes on T1­6 and spot on T7; small spots on latero­apical margins of S2­6. Inner surface of flagelum light reddish brown; legs with dark to reddish brown areas in addition to yellow marks.

Structure as in female, except usual sexually dimorphic characteristics and as follows: apical flagellomere hooked; posterior margin of S2 with a strong and blunt medial protuberance; S8 distinctly convex in lateral view.

Measurements (in mm): fore wing length, from middle of tegula to apex, 7.52; approximate body length, 9.0; head maximum width, 2.48; head height, from apex of clypeus to vertex, 2.32.

Type material

Holotype female, Brazil, Minas Gerais: “ Brasil, Minas Gerais, 15 km sul da Jaíba, 8.iv.1998, G.A.R. Melo”. Paratypes: 2 females, same data as the holotype, except “ 9.iv.1998 ”; Bahia: 1 male, “ ANAJÉ, BAHIA, BRASIL, 20­V­1975, C. & P. Elias leg ”.

Biology

The females of T. robusta n. sp. were collected on flowers of an unidentified species of Waltheria (Sterculiaceae) growing in abandoned pasture land. This region in northern Minas Gerais is within the southern limit of the caatinga domain, the xeric plant formation occupying most of northeastern Brazil.

Four nests were found along a dirt road not far from where the females were collected. Three of them formed a loose aggregation (the entrances were 10 to 15 cm apart). The soil in the area was very sandy with some intermixed clay. The entrances were provided with a short vertical mud turret of about 1.5 to 2 mm in height and 4.5 mm in external diameter (wall about 0.9 mm thick). The main burrow was a vertical tunnel about 20 to 25 cm deep; no lateral shafts were excavated. Its diameter was similar to the inner diameter of the turret (3.6 mm). The nests contained only two contiguous cells, inclined about 45°, at the end of the main burrow ( Figs. 13, 15 ). The cells were elongate, suboval, with the inner surface smooth and polished (14.3–17 mm long and 4.4–6 mm in its greater diameter) ( Fig. 14 ). The cell walls were built with plastered mud and were about 0.65–0.8 mm thick.

Little is known about the nesting biology of the species of the genus Trimeria ( Mechi 1999a; Mechi 1999b; Neff & Simpson 1985; Zucchi et al. 1976). The nest architecture of T. robusta n. sp. agrees with the general pattern known for other species in the genus.

Figures

FIGURES 1 – 9. 1, Trimeria robusta n. sp. (holotype female), head in frontal view. 2, T. robusta n. sp. (paratype male), head in frontal view. 3, T. rubra n. sp. (holotype female), head in frontal view. 4, T. robusta n. sp. (holotype female), lateral view. 5, T. robusta n. sp. (holotype female), mesosoma in dorsal view. 6, T. robusta n. sp. (paratype male), lateral view. 7, T. robusta n. sp. (paratype male), mesosoma in dorsal view. 8, T. rubra n. sp. (holotype female), lateral view. 9, T. rubra n. sp. (paratype female), mesosoma in dorsal view. Fig. 5 was modified on Photoshop CS for Windows (lower half was flipped vertically to fill the upper half), because the insect pin was masking part of the picture. Scale bar for figures 1 – 3, 5, 7 and 9: 2 mm. Scale bar for figures 4, 6 and 8: 5 mm.

FIGURES 10 – 15. 10, Trimeria robusta n. sp. (holotype female), suctellum in dorsal view. 11) T. rubra n. sp. (holotype female), scutellum in dorsal view. 12, T. rubra n. sp. (holotype female), hind tibia. 13 – 15, T. robusta n. sp., nest detail showing the main burrow and cells. Scale bars for figures 10 – 12: 1 mm. Scale bars for figures 13 – 15: 10 mm.