Eurytoma Illiger, 1807

Gómez, José Francisco, Nieves-Aldrey, José Luis, Nieves, María Hernández & Stone, Graham Nicholas, 2011, Comparative morphology and biology of terminalinstar larvae of some Eurytoma (Hymenoptera, Eurytomidae) species parasitoids of gall wasps (Hymenoptera, Cynipidae) in western Europe, Zoosystema 33 (3), pp. 287-323 : 297-301

publication ID	https://doi.org/ 10.5252/z2011n3a3
DOI	https://doi.org/10.5281/zenodo.4547009
persistent identifier	https://treatment.plazi.org/id/03E487A7-AF41-2772-05FE-FB456B2EFE28
treatment provided by	Felipe
scientific name	Eurytoma Illiger, 1807
status

Treatment

Genus Eurytoma Illiger, 1807 View in CoL View at ENA

DESCRIPTION

Body in ventral view ( Figs 5 View FIG ; 6 View FIG ) fusiform or barrelshaped in most species, slightly broadest around the middle (segments ABS3-ABS5) and tapering gradually towards anal segment, which is normally broader than long; the ratio L/W is usually 1.3-2.2; in lateral view ( Figs 7 View FIG ; 8 View FIG ) body ventrally curved; ventral margin of abdominal body segments usually clearly convex in profile.Anterodorsal protuberances always visible at least in one thoracic and abdominal segment, being clearly protruding outwards in most species.Colour whitish.Integument generally smooth or slightly rugose in body and cephalic capsule. Body moderately setose displaying a pattern composed by only three rows of setae at least in the thoracic segments (a dorsal, lateral and ventral rows); setae much shorter than length of body segment except in the thoracic area that could have relatively longer setae but not more than the length of a body segment.

Head in anterior view ( Figs 9 View FIG ; 10 View FIG ) more or less hemispherical or trapezoid, with mouth parts protruding; head approximately 1.1-1.3 times as broad as high, with anterior margin of vertex slightly concave in most species and the medial area of vertex not incised. Head with basic chaetotaxy, comprising no more than 5-7 pairs of clearly visible setae.

Vertex with one pair of relatively short erect setae with the separation between this pair varying between species; antero-medial setae of antennal area situated mostly at the same level or slightly either above or below the antennae, their length in most species intermediate but varying between them; the antero-medial setae of vertex usually situated relatively high on the upper face, much closer to the anterior margin of the vertex than to the antennae, as their precise position constitutes a variable character between species. Antennal area indistinct; antennae variable in size and situated more or less at the middle of the head; one pair of clypeal setae present, situated laterally above the level of ventral margin of clypeus; a pair of dorsal-labral setae present, situated above the labrum just at the level of ventral margin of clypeus, and generally as long as clypeal setae. Ventral margin of clypeus straight and more or less visible in each species.

Mouth parts ( Figs 11 View FIG ; 12 View FIG ) with labrum subrectangular and divided into two lateral flaps and one medial part, which is in turn subdivided into five more or less differentiated lobes; subdivision of medial part of the labrum can be slight, and ranges from limited to the apical part of labrum (e.g., Eurytoma brunniventris ) to deep and almost reaching the level of labral setae (e.g., Eurytoma rosae ), according to species. Maxillae differentiated or not from labium but only slightly protruding from it; maxillary palps sometimes easily visible; labial palps visible or not, sometimes conspicuous.

Mandibles ( Fig. 13 View FIG ) usually symetrical (except for Eurytoma strigifrons within studied species), with the apical tooth generally visible or exposed in part, at least the tip being visible; always more than one tooth in each mandible with the shape of the first tooth variable according to species, ranging from relatively short and wide (e.g., Eurytoma rosae ) to long and slender (e.g., Eurytoma infracta ) (ratio L/W 1T variable); secondary tooth smaller and shorter than first, its tip either straight or recurved or slightly blunt.

MONOPHYLY AND RECOGNITION

With around 699 described species, Eurytoma is the largest genus of the Eurytomidae ( Noyes, 2003) . The genus is complex and still presents many taxonomic and phylogenetic problems ( Zerova 1988; Lotfalizadeh et al. 2007a). The lack of a useful and valid phylogenetic classification for Eurytoma species is associated with uncertainty over the generic limits of Eurytoma , Bruchophagus and allied genera. Identification keys have long used artificial arrangements, as in the key proposed by Burks (1971). A recent review based on morphological characters of adults indicates Eurytoma is polyphyletic ( Lotfalizadeh et al. 2007a).

The species whose larvae we have studied belong to three different Eurytoma species groups – the cynipsea group, the robusta group and the rosae group. A general pattern in some Eurytoma groups is the presence of sibling species that are very similar as adults but which show some differences in their immature stages ( Claridge & Askew 1960). Differences among Eurytoma species will be discussed later.

BIOLOGY

Species of Eurytoma are predominantly endophytic, either as phytophagous or as parasitoids of phytophagous insects. The species included in this study are all ectoparasitoids in galls of Cynipidae on herbs, shrubs and trees in the families Lamiaceae , Asteraceae , Rosaceae , Sapindaceae and Fagaceae . Almost all of the species also feed on gall plant tissue at the end of their final larvae stage.