Pristomerus rivier Rousse et Villemant

Rousse, Pascal & Villemant, Claire, 2012, Ichneumons in Reunion Island: a catalogue of the local Ichneumonidae (Hymenoptera) species, including 15 new taxa and a key to species, Zootaxa 3278, pp. 1-57 : 21-22

publication ID 10.5281/zenodo.214150


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Pristomerus rivier Rousse et Villemant

sp. nov.

Pristomerus rivier Rousse et Villemant , sp. nov.

( Figs 12 View FIGURE 12 a–b)

Diagnosis. This is the only Pristomerus species in Reunion. The acute femoral tooth and the rather large thyridiae near base of tergite II are characteristics of the genus. Within the studied area, Pristomerus rivier can be distinguished by its black face, its black brown mesosoma with reddish mesonotum and its strong femoral tooth in both sexes.

Description. FEMALE (3 specimens). Fore wing length 3.6–4.1 mm.

Head. Temples short, rounded, head strongly transverse, abruptly constricted behind eyes; vertex and frons finely granulate; ocellar triangle equilateral, OOi = 1.3, IOi = 1.1; face finely, regularly and densely punctate, more granulate laterally, with white hairs; clypeus convex, sparsely punctate and shining, its ventral margin slightly convex, impressed, Ci = 2; MLMi = 0.6; mandible basally wide, short, stout, with two subequal teeth, its ventral basal third flanged; antenna short with 24–27 flagellomeres, FLi = 5, penultimate flagellomeres almost quadrate.

Mesosoma. Pronotum, pleurae including speculum and propodeum shining, densely and regularly punctate; mesonotum densely punctate granulate, its median lobe convex, notaulus large and distinctly impressed in the anterior third of mesoscutum, scuto-scutellar groove deep, shining, with short longitudinal striations; scutellum densely punctate without lateral carina; propodeum strongly punctate, propodeal carination strong, complete, area basalis petiolate, area superomedia short, 1.5 x longer than wide, and area petiolaris twice longer than area superomedia. Legs slender, femoral tooth present strong, about as high as wide, and 0.5x the height of femur, tooth followed by a raw of denticles.

Metasoma. Tergite I slightly longer than tergite II, tergite II about 1.3 x longer than wide, tergite III slightly transverse, thyridiae oval, oblique and converging. Tergites I-II longitudinally striate, tergite III basally aciculate, the following tergites smoother; OTi = 1.8, ovipositor tip sinuate.

Color. Head black brown with clypeus, scape, pedicel and first segment of flagellum orange, mandible and palpi yellow, flagellum reddish brown; mesosoma black brown, mesoscutum reddish brown with median and lateral lobes darker, scutellum reddish brown; legs yellow orange, hind tibia and sometimes hind femur apically infuscate; metasomal tergites I-II black brown with a thin yellow margin; basal 0.6 of tergite III black brown, apical margin yellow, other tergite yellowish, basally infuscate.

MALE (2 specimens). Fore wing length 3.8–4.1 mm. Femoral tooth a little stronger, eyes strongly convergent dorsally, touching median ocelli; tergite III yellow, the following dark brownish.

Host records. Recorded from Plutella xylostella ( Lepidoptera : Plutellidae ) on cabbage ( Brassica oleracea ) and Olethreutes sp. ( Lepidoptera : Tortricidae ). Nevertheless, as no Olethreutes sp. is known from Reunion ( Martiré & Rochat 2008), this latter host record seems to be a misidentification of an undetermined Olethreutinae species.

Distribution records. Reunion.

Type material. HOLOTYPE Ƥ ( MNHN EY 3897) Verbatim label data: 14373 RQ 3220, La Réunion, Petit St Pierre, sur Litchi sinensis , 19/06/1996, Quilici S. leg.; complete. PARATYPES ( MNHN 6432–6433) 13 same locality, same date, leg. Cirad; 13 St Benoit / Bras Madeleine, same date, leg. Cirad. Other material 1Ƥ St Paul / Tan Rouge, alt. 800m, V.2011, leg. Cirad; 13 Le Tampon / Bras de Pontho, alt. 780m, X.1999, “ex Plutella xylostella on Brassica oleracea ”, leg. Cirad; 1Ƥ Ste Rose, VIII.1997, “ex Olethreutes sp.”, leg. Cirad.


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