Plagiotrochus vilageliui, Pujade-Villar & Villemant & Andreï-Ruiz, 2000

Pujade-Villar, Juli, Villemant, Claire & Andreï-Ruiz, Marie-Cécile, 2000, Cynipidae associated with Quercus collected in Corsica with the description of a new Plagiotrochus species (Hymenoptera, Cynipoidea), Zoosystema 22 (4), pp. 835-846 : 841-843

Plagiotrochus vilageliui n. sp. Pujade-Villar (agamic form)

( Figs 2 ; 3 )

TYPE MATERIAL. — El Toscar. Tarragona, Spain, holotype agamic ♀, captured 3.IV.1988 ( UB). Paratypes, same data as holotype, 12 agamic ♀ ♀ (ref. C3-41).

Matadepera. Barcelona , Spain, ex. Q. coccifera , (6.IV.1987) 20.IV.1987: 1 agamic ♀ (ref. C4-18) ( UB) ; idem (11.IV.1987) 13.IV.1987: 1 agamic ♀ (ref. C4-24) ( UB) ; idem (2.IV.1987) 12.IV.1987, 1 agamic ♀ (ref. C4-21) ( UB) ; idem 19.IV.1987, captured, 1 agamic ♀ (ref. C4-25) ( UB) .

Ctra de Santa Fe del Montseny. Barcelona, Spain, captured 29.IV.1987, 1 agamic ♀ (ref. C10-58).

Corella. Navarra, Spain, ex. Q. ilex (X-1997) extr. 3.XI.97, 1 agamic ♀ (Iguiñiz leg.) (UB).

Vallée du Fango. Corsica, France, yellow pan trap (1-7.V.1993), 1 ♁ (ref. R1/DA/C, Andrei-Ruiz leg.) (MNHN).

ETYMOLOGY. — This name was chosen to honour the mother of my daughters, Roser Vilageliu i Grau.

DIMENSIONS. — Length 2.5- 3 mm.

COLORATION. — Body amber or reddish brown, but some zones of the thorax, mainly the basal part of mesopleura and propodeum, dark brown. Dorsoposterior part of metasoma with a more or less expand- ed black mark. Legs with the same coloration as the thorax. Antenna brown, except for the two first antennomeres which are light brown. Wings translucent, with brown veins.

DESCRIPTION

Head ( Fig. 2A )

With short, sparse and flat pubescence. In frontal view, 1.2 time wider than high. Ventral margin of clypeus slightly incised. Face with weak radiating carinae ( Fig. 2A ). Distance between compound eyes similar to their height. Distance between toruli and compound eyes 2.5 times distance between toruli. Genae with coriaceous sculpture. Frons weakly depressed, with a conspicuous median ridge ( Fig. 2A ) and 2.3 times wider than long in dorsal view. Vertex and occiput with coriaceous-alutaceous sculpture. In dorsal view, genae clearly expanded behind the eyes. Pol:ool:lol are 17:8:7; diameter of lateral ocellus: 5, smaller to lol distance.

Antenna ( Fig. 3A )

Fourteen antennomeres, pedicel twice as long as wide, first flagellomere 1 curved and more than three times longer than the width; the fourth segment as long as or longer than the third one, but conspicuously wider; length of the remaining segments gradually decreasing, the 13 th one at least 1.5 time longer than the width. Sensillae from second flagellomere very conspicuous.

Mesosoma ( Fig. 2 B-D)

Sparsely pubescent. In lateral view ( Fig. 2C ), relatively short and high, nearly 1.5 time as long as high; in the same view, the mesonotum is quite humped, forming a straight angle with the pronotum. Mesoscutum in dorsal view ( Fig. 2B ) clearly longer than wide and 1.4 time as long as the scutellum. Pronotum in lateral view ( Fig. 2C ) with a coriaceous-rugulose sculpture and with several longitudinal carinae. Scutum weakly sculptured, coriaceous-alutaceous and in lateral view with several carinae running perpendicularly over the pronotum margin ( Fig. 2B, C ). Notauli weakly marked, not reaching one-third of the length of the mesoscutum ( Fig. 2B, C ). Median mesoscutal impression missing ( Fig. 2B ). Scutellar sculpture similar to that of the mesoscutum, scutellum trapezoidal and margined in dorsal view ( Fig. 2B ), flat in lateral view ( Fig. 2C ). Scutellar foveae well set off, oval and smooth. Metanotal trough smooth and glabrous without carinae. Propodeum ( Fig. 2D ) with two curved submedial carinae and with an incomplete medi- an carina. Mesopleura almost wholly sculptured, with a small, smooth area in its basal part.

Wings ( Fig. 3B )

Forewing with radial cell open at the margin and four times longer than wide. R1 and Rs veins do not reach the margin of the wing; R1 weakly angled and 2r vein strongly angled. Areolet present.

Legs

Tarsal claws simple.

Metasoma

Oval, as long as high. Nearly bare. Third and following terga punctured laterally. Hypopygial spine short; in lateral view twice as long as the height; in ventral view 2.5 to 3 times as long as the breadth, with short and sparse pubescence.

Gall ( Fig. 3C )

Collected in the northeastern Iberian Peninsula on Quercus coccifera and in the North Iberian Peninsula on Q. ilex . Larval chambers isolated from each other, in twigs with a diameter of less than 0.5 cm. The galls are not visible externally, so they are easily overlooked. In Corsica, they are also present on Q. ilex because the Plagiotrochus vilageliui adults are found on both hosts ( Q. ilex and Q. coccifera ) and Q. coccifera is absent from Corsica.

REMARKS

The colour and the presence of a margined scutellum with trapezoidal form relate this new species to P. kiefferianus . However, morphological characters of P. kiefferianus Tavares, 1901 greatly differ according to the host-plant bearing the galls ( Quercus ilex or Q. coccifera ) (Pujade-Villar 1991). P. vilageliui n. sp. forms a completely different gall. Moreover it is easily distinguished by its antennal segments, which are longer (1.7 to 2 times longer than wide), the presence of a conspicuous frontal carina and the humped mesonotum, both absent in P. kiefferianus . Another agamic form, Plagiotrochus australis (Mayr, 1882) , also makes galls on Q. ilex , but its adults differ from P. vilageliui . P. vilageliui differs from P. australis in lacking percurrent notauli, lacking the median mesoscutal impression, having a quadrangular thorax and the sculpture as well as the relative length of the first antennomeres are different shape.

Figures

FIG. 2. — SEM pictures of Plagiotrochus vilageliui n. sp agamic form; A, head, frontal view; B, dorsal view; C-D, mesosoma; C, lateral view; D, propodeum. Scale bars: A, D, 200 µm; B, C, 500 µm.

FIG. 3. — Some morphological details of Plagiotrochus vilageliui n. sp (agamic form); A, antenna; B, forewing without pubescence; C, gall. Scale bars: 0.5 mm.