Synergus Hartig, 1840 (Synergini)

Nastasi, Louis F., Buffington, Matthew L., Davis, Charles K. & Deans, Andrew R., 2024, Key to the North American tribes and genera of herb, rose, bramble, and inquiline gall wasps (Hymenoptera, Cynipoidea, Cynipidae sensu lato), ZooKeys 1196, pp. 177-207 : 177

publication ID	https://dx.doi.org/10.3897/zookeys.1196.118460
publication LSID	lsid:zoobank.org:pub:D10E0EA0-16D7-42B9-83D9-3871CBF06FE1
persistent identifier	https://treatment.plazi.org/id/F3875393-5486-52E8-A5E0-41E7FD45E6D4
treatment provided by	ZooKeys by Pensoft
scientific name	Synergus Hartig, 1840 (Synergini)
status

Treatment

Synergus Hartig, 1840 (Synergini) View in CoL View at ENA

Figs 83-86 View Figures 83–86

Type species.

Synergus vulgaris Hartig, 1840.

Diagnosis.

Pronotum tall and broad dorsomedially. Pronotal submedial pits distinct and well-impressed. Pronotal plate present but mostly indistinct. Mesoscutellar foveae usually distinct. Fore wing always with marginal cell closed (apparently only partly closed in Synergus mexicanus Gillette, 1896; see Pujade-Villar et al. 2015). Metatarsal claws with or without basal lobe. Metasoma with syntergite, with second and third tergites entirely fused, greatly enlarged, and occupying most of metasoma. Body generally strongly sculptured.

Note.

Sixty-one species of Synergus are known from North America ( Nastasi and Deans 2021). Members of Synergus Hartig are inquilines of galls induced by Cynipini on oaks ( Buffington et al. 2020). Synergus are extremely commonly reared and are known in association with hundreds of oak gall wasps ( Nastasi and Deans 2021; Ward et al. 2022). Synergus is demonstrably polyphyletic, with North American taxa forming as many as three independent clades and many undescribed species exist ( Pénzes et al. 2012; Lobato-Vila and Pujade-Villar 2021; Lobato-Vila et al. 2022), meaning a great deal of revisionary work will be needed to resolve major questions within the genus and better understand its diversity.

The genus Saphonecrus Dalla Torre & Kieffer (Tribe Synergini ) has long been considered present in North America, but recent taxonomic work refutes this idea. Nastasi and Deans (2021) reported two species: S. favanus Weld and S. gemmariae (Ashmead). Saphonecrus gemmariae was reported in error as the species was considered incertae sedis by Lobato-Vila et al. (2022) due to missing type material which was supposedly deposited in the National Museum of Natural History (USA, D.C.). Upon our own examination of the USNM collection, we were unable to locate the relevant type material. Similarly, the status of S. favanus is also questionable ( Pénzes et al. 2009; Pénzes et al. 2012; Lobato-Vila and Pujade-Villar 2021); this species may represent a new genus distinct from other Synergini ( Lobato-Vila et al. 2022). As such, we consider the presence of Saphonecrus in North America doubtful and have omitted Saphonecrus from the above key. We have examined type material of S. favanus deposited in USNM (specimen # USNMENT960420 and three additional individuals) and found that in the key to genera, the specimens key to Synergus , bearing no strong distinction from this genus. The taxonomy of the tribe Synergini as a whole is currently uncertain, and ongoing efforts to revise it will likely result in a stronger understanding of the North American fauna ( Lobato-Vila et al. 2022).