Neuroterus Hartig, 1840

Melika, George, Pujade-Villar, Juli, Abe, Yoshihisa, Tang, Chang-Ti, Nicholls, James, Wachi, Nakatada, Ide, Tatsuya, Yang, Man-Miao, Pénzes, Zsolt, Csóka, György & Stone, Graham N., 2010, 2470, Zootaxa 2470, pp. 1-79 : 20-21

Neuroterus Hartig, 1840

Figs 127–133, 134–137, 138–145, 146–151, 152–157.

Type species: Neuroterus politus Hartig, 1840 . Designated by Ashmead (1903).

Synonyms: Neuroterus Hartig, 1840 . Type species: N. politus Hartig , designated by Ashmead (1903).

Spathegaster Hartig, 1840 . Type species: S. petioliventris Hartig , by original designation. Synonymized by Mayr (1881).

Ameristus Foerster, 1869 . Type species: N. politus , designated by Rohwer & Fagan (1917). Synonymized by Mayr (1881).

Dolichostrophus Ashmead, 1887 . Type species: Cynips quercusirregularis Osten Sacken, 1861 . Designated by Ashmead (1887). Synonymized by Dalla Torre (1893).

Neuroterus subgenus Diplobius Kinsey, 1923 . Type species: Cynips floccosa Bassett, 1881 by original designation. Synonymized by Melika & Abrahamson (2002).

Neuroterus subgenus Dolichostrophus Kinsey, 1923 . Type species: Cynips irregularis Osten Sacken, 1861 by original designation.

Neuroterus subgenus Neospathegaster Kinsey, 1923 . Type species: Cynips vesicula Bassett, 1881 by original designation.

Neuroterus subgenus Neuroterus Kinsey, 1923 designated as the nominal subgenus of Neuroterus .

Neuroterus subgenus Spathegaster Kinsey, 1923 . Type species: Spathegaster petioliventris Hartig by original designation.

Neoneuroterus Monzen, 1954 . Type species: N. kashiyamai Monzen by original designation. Synonymized by Melika & Abrahamson (2002).

Repentinia Belizin & Maisuradze, 1961 . Type species: R. lencoranica Belizin & Maisuradze, 1961 by original designation ( Maisuradze, 1961). Synonymized by Melika & Abrahamson (2002).

Diagnosis. Entire body with very few sparse short white setae. Head rounded in anterior view, never transverse or trapezoid, genae not or very slightly broadened behind compound eyes, usually invisible in anterior view ( Figs 127, 138, 141, 152). Head not broader than width of mesosoma. In sexual females and especially males compound eyes are strongly enlarged and the transfacial distance short, equal or shorter than the height of the eye and the height of the eye about 3.0 times (in sexual females, Fig. 138) or 5 – 6.0 times (in males, Fig. 141) larger than the height of the malar space. Malar sulcus present, in some species indistinct but always traceable ( Figs 127, 138, 141, 152). Both asexual and sexual female antennae with 13 flagellomeres ( Figs 129, 140). Notauli absent or incomplete, present in the posterior 1/2 or 1/3 of the mesoscutum, always superficial ( Figs 130, 145). If the superficial notauli nearly reaching the pronotum, than malar sulcus deep, distinct ( N. tricolor (Hartig) , asexual generation). Hind tarsal claws with a distinct basal lobe. Only in the case of the sexual generation of one Palaearctic species, N. tricolor , the tarsal claw is simple, but the female antenna with 13 flagellomeres. The prominent part of the ventral spine of the hypopygium at least 3.0-4.0 times as long as broad in ventral view ( Figs 136 – 137, 150, 157). In the male antennae, F1 slightly or not modified, never expanded and flattened, sometimes only curved or similar in shape to F2, subequal or slightly longer than F2 ( Fig. 143) ( N. albipes (Schenck) , N. anthracinus (Curtis) , N. numismalis (Geoffroy in Fourcroy), N. quercusbaccarum (L.), N. tricolor ). See also Diagnosis to Cerroneuroterus .

Two species in the Western Palaearctic, N. anthracinus ( Figs 152 – 157) and N. politus , have some distinct morphological peculiarities. The first differs from all other known species by a distinct and complete transscutal articulation, in which the boundary between the mesoscutum and mesoscutellum is straight ( Fig. 155). In both species lateral propodeal carinae are distinct, complete, delimiting a smooth, shiny central propodeal area ( Fig. 156). The transfer of N. anthracinus from Andricus to Neuroterus ( Pujade-Villar et al. 1998) is supported by the recent phylogenetic reconstructions ( Stone et al. 2009), while N. politus is isolated from congenerics in all phylogenetic reconstructions. At this point we retain all below mentioned species in Neuroterus pending further data and analysis. Yukawa & Masuda (1996) recorded N. politus (= N. aprilinus (Giraud) in Japan and their figures C – 132 and C – 149 show the galls of sexual and asexual generations, respectively. However, although the galls illustrated in Yukawa & Masuda (1996) are certainly very similar to those of N. politus , identification was made on the basis of galls only, and adults have yet to be examined. We thus regard it as better to assign these galls to an undescribed species until adult wasps have been reared and compared with western palaearctic N. politus .

Twelve species of Neuroterus were listed for the Western Palaearctic, with detailed descriptions and data on lifecycles and distribution ( Melika et al. 2000; Nieves Aldrey 2001; Melika 2006a). Our redelineation of Neuroterus in fact reflects Kinsey’s (1923) subgenus Spathegaster , into which he placed all the above-mentioned species except N. politus . We prefer the commonly established name Neuroterus and leave Spathegaster as a junior synonym. In our modified delineation, the genus Neuroterus comprises only 6 Western Palaearctic species ( N. albipes , N. anthracinus , N. numismalis , N. politus , N. quercusbaccarum , and N. tricolor ), all of which have alternating sexual and asexual generations only galling oaks in section Quercus s.s.

Recently a list of the Eastern Palaearctic Neuroterus species , with some taxonomic comments, was given in Abe et al. (2007). All Neuroterus species described by Ashmead (1904), Dettmer (1934) and Monzen (1954) from Japan will be examined and discussed elsewhere, including Aphelomyx [sic!] crispulae Mukaigawa, Aphelomyx [sic!] glanduliferae Mukaigawa ( Mukaigawa 1920a, b), as well as species of Dryophanta Förster described by Ashmead (1904) which we think may well be representatives of Neuroterus .

Around eighty species of Neuroterus have been described from the Holarctic Region. Burks (1979) listed 52 species for America north of Mexico, the majority of which are restricted to the eastern United States. Recently a number of new species from the USA have been described ( Melika & Abrahamson 1997). The striking feature of all known Nearctic Neuroterus species is that with a single exception all are associated only with white oaks (section Quercus s.s.), and none are associated with the diverse North American red oaks (section Lobatae). The exception is N. chrysolepis Lyon from California, which induces galls on Q. chrysolepis Liebm. (section Protobalanus, a golden cup oak) ( Lyon 1984). A preliminary examination of many Nearctic Neuroterus types indicates that some of them are synonymous ( Melika & Abrahamson 1997, 2002) and several species do not fit into the currently designated Neuroterus limits. Nearctic Neuroterus need a thorough revision, which is beyond the scope of the current study.