Apparently restricted to saltmarsh habitat, with a number of inland records considered unsafe as a result. Coastal records are known from about 10 locations north to Spurn on the east coast, and to the Solway on the west coast. A notable lack of records still from the Wash and north Norfolk. There appear to be no records since one at Kenfig Burrows in 1993. Whilst it is possible this species is going overlooked, the upper margins of saltmarshes are a habitat at risk from sea-level rise, and so this should rightly be considered a priority species (Musgrove, 2023).
An entirely black species with no visible microsculpture on the first three tergites and the other tergites with transverse alutaceous surface sculpture. The front lobe and the lateral lobes of the mesonotum and the scutellum all with a large shining puncture free or with a few feeble punctures. Identification is best determined by examination of the genitalia aided by its association with estuarine and salt marsh habitat. .
Associated with salt marshland. The foodplants of Dolerus pachycerus is saltmarch rush.
GB IUCN Status: Critically Endangered
GB Rarity Status: Nationally Rare
Distribution: England, Scotland, Wales
Flight period: May to June
Plant associations: Juncus gerardii (saltmarsh rush).
Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London
Liston A, Knight G, Sheppard D, Broad G, Livermore L (2014) Checklist of British and Irish Hymenoptera - Sawflies, ‘Symphyta’. Biodiversity Data Journal 2: e1168. https://doi.org/10.3897/BDJ.2.e1168
Musgrove, A.J. 2023. A review of the status of sawflies of Great Britain - Phase 2: The Athaliidae and the Tenthredinidae (excluding Nematinae). Natural England, unpublished