Gallastichus Rasplus & La Salle, gen. nov.
Creators: name: Rasplus, Jean-Yves
name: Salle, John La
name: Delvare, Gérard
name: Mckey, Doyle
name: Webber, Bruce L
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Ormyridae
Gallastichus

description: Gallastichus Rasplus & La Salle gen. nov.   
(Figs 1 A–E, 2A–D, 4A)  
 Type species: Gallastichus mutuus Rasplus & La Salle, sp. nov. Gender masculine.   
 Etymology. The generic name refers to the gall-inducing biology of this wasp.   
 Diagnosis. Head not collapsing when dry. Lower face without impressions or grooves. Toruli placed high on frons and distinctly closer to median ocellus than clypeal margin (Fig. 1 A). Ocellar triangle not surrounded by grooves. Scape strongly compressed, blade-like (Fig. 1 C & D) and extending dorsally distinctly above level of vertex (Fig. 1 B). Four anelli present. Mesoscutum without median line. Notauli deep. Axillae strongly projecting anteriorly. Fore wing fairly to densely pilose (Figs 1 B & E, 2D). Costal cell of fore wing narrow. Parastigma and base of marginal vein fairly thickened (Figs 1 B & E, 2D). The two longest cercal setae roughly equal in length and slightly curved but not sinuate (Fig. 2 B).   
 Description. Female. Malar sulcus present, straight or only slightly curved (Fig. 1 A & B). Anterior margin of clypeus distinctly bilobed (Fig. 1 A). Ocelli placed in a close triangle, ocellar-ocular distance (OOL) roughly equal to post-ocellar distance (POL). Small, indented area present just lateral of lateral ocellus. Toruli placed high on frons and closer to median ocellus than clypeal margin. Antenna with 4 anelli, the first as long as the next two together, the fourth variable (Fig. 1 C).   
Mesoscutum mostly coriaceous (Fig. 2 A), without a median line or groove, with deep notauli, and with 1–4 adnotaular setae (Fig. 2 C). Axillae strongly projecting forward (Fig. 2 A & C); scapular flanges linear. Scutellum weakly coriaceous; submedian grooves present or absent (Fig. 2 C); sublateral grooves deep and distinct, with several longitudinal carinae lateral to sublateral groove; frenal groove separating narrow, transverse posterior strip (Fig. 2 C). Dorsellum convex or as a plate (Fig. 2 C). Fore wing elongate; densely setose on wing blade, costal cell narrow, parastigma and base of marginal vein fairly thickened (Figs 1 B & E, 2D). Hind wing with numerous microtrichiae facing hamuli (Fig. 2 D). Petiole small, transverse, without sculpture (Fig. 2 C). Gaster smooth, elongate, with the two longest cercal setae roughly equal in length and slightly curved but not sinuate (Fig. 2 B).  
 Male. Similar to female except for antenna (Fig. 1 C), colour (Fig. 1 E) and sexual characters. Scape with or without ventral plaque situated apically, when present the latter situated apically, on flattened ventral expansion (Fig. 1 C). All funicular segments longer than wide, and with a basal whorl of setae.   
 Discussion. Keys to genera of Tetrastichinae have been provided for Europe (Graham 1987; 1991), Australia (Bouček 1988) and North America (La Salle 1994; Schauff et al., 1997). Gallastichus does not satisfactorily key in any of these works. It is similar to the North American Oxypracetus La Salle and Lisseurytomella Gahan & Fagan and the Australian Pracetus Bouček, but differs from all these genera in lacking a distinct, sculptured petiole. Rather, the genus appears to be closely related to Ceratoneura Ashmead, and Bouček (1976) erroneously transferred to Ceratoneura a species described by Risbec that actually belongs to Gallastichus (Delvare in prep.). At least the structure of the anelli links Ceratoneura and Gallastichus. In one species group of the genus, the last anellus is elongate and bears apical hairs unlike the preceding anelli. The last anellus thus appears similar to the funicular segments except that it does not bear any MPS (multiporous plate sensilla). Gallastichus is also morphologically similar to a group of Neotropical tetrastichines associated with galls, which includes genera such as Galeopsomyia Girault, Cirrospilopsis Brèthes, Paragaleopsomyia Girault, and the seed-predator Lisseurytomella Gahan & Fagan (La Salle 2005). This group tends to be characterised by species that are generally larger and more sclerotized than other tetrastichines, often with a long scape placed high on the head, and a reduced number of setae on the dorsal surface of the submarginal vein. However, in these genera, the lower face and frons have impressions and one cercal seta is much longer than others and kinked.   
The genus includes two different species groups that can be separated as follows:  
 Scape with linear sensillum along ventral margin in female, with protruding sensillar plate in male. Last anellus much longer than wide, as broad as funicle. First anellus only slightly longer than broad. Flagellum of female with funicle clearly 3-segmented and club without deep constrictions between segments. Propodeal callus with 2 hairs. Stigmal vein of fore wing forming a strongly acute angle with front margin of wing. Stigma not especially elongate. PMV absent.................................................... species group 1 (including G. m u t u u s and a species described by Risbec)   
 Scape without sensillar plate in both sexes. Last anellus discoid. First anellus distinctly longer than wide and much narrower than following segments. Flagellum of female with segmentation not clear because C1 and C 2 may appear as funicle segments because of a deep constriction between them. Propodeal callus with numerous hairs (> 15). Stigmal vein forming a slightly acute angle (70°) with front margin of wing. Stigma elongate. PMV visible as a stub................................................................ species group 2 (one species described by Risbec, one undescribed species) Biology. Some Ceratoneura species are phytophagous, for example Ceratoneura indi Girault (in India and   
 Africa) on Solanum spp. or Ceratoneura sp. (in West Indies; Jean Etienne, pers. comm., after dissections of dam-   
 aged floral parts or seeds). Gallastichus host plants belong to different and unrelated plant species: Harungana   
 madagascariensis Lam. ex Poir. (Haronga) (Hypericaceae), Aphloia theiformis (Vahl) Benn. (Aphloiaceae) and   
 Syzygium cymosum (Lam.) DC (Myrtaceae). Gallastichus appears to have its highest diversity in Madagascar and   
neighbouring islands.
description: Published as part of Rasplus, Jean-Yves, Salle, John La, Delvare, Gérard, Mckey, Doyle & Webber, Bruce L, 2011, A new Afrotropical genus and species of Tetrastichinae (Hymenoptera: Eulophidae) inducing galls on Bikinia (Fabaceae: Caesalpinioideae) and a new species of Ormyrus (Hymenoptera: Ormyridae) associated with the gall, pp. 51-59 in Zootaxa 2907 on pages 52-53, DOI: 10.5281/zenodo.277771