Enicospilus Stephens, 1835

Broad, Gavin R. & Shaw, Mark R., 2016, The British species of Enicospilus (Hymenoptera: Ichneumonidae: Ophioninae), European Journal of Taxonomy 187, pp. 1-31 : 4

Genus Enicospilus Stephens, 1835

Taxonomy of British Enicospilus

There have been no identification keys to British Enicospilus since Gauld’s (1973) key and update ( Gauld 1974). Unfortunately, these works contained significant misidentifications and lumped some species together. This is not surprising, as Gauld had access to rather small sample sizes and relied heavily on the number and shape of fore wing sclerites, which are of great use in Enicospilus taxonomy but are, unfortunately, almost identical in five of the British species. There has never been a thorough revision of European Enicospilus species, which is reflected in some frequent misunderstandings regarding species names and limits, although Viktorov’s (1957) key is very useful. In Britain, Enicospilus can be divided into three species-groups, based on the sclerites in the fore wing discosubmarginal cell: E. inflexus and E. undulatus entirely lack sclerites (and have been referred to the genus Allocamptus Förster, 1869 by some authors); E. merdarius (= Ophion tournieri Vollenhoven, 1879 ) and E. repentinus have a welldefined proximal sclerite, with the central sclerite either absent or transparent; and the remaining five species (the ramidulus species-group) have both the proximal and central sclerites pigmented. There has been confusion in each of these species-groups, although it is within the ramidulus complex that species are most morphogically similar and hence have been persistently confused.

Gauld (1974) separated the very similar E. inflexus ( Ratzeburg, 1844) and E. undulatus ( Gravenhorst, 1829) , that he had previously ( Gauld 1973) confounded under the name E. undulatus ; and Viktorov (1957) had already separated E. repentinus and E. tournieri (but see below), which Gauld (1973) had confused by identifying British specimens of E. merdarius (= tournieri ) as E. repentinus , whereas the true E. repentinus had not been found in Britain at that time.

Most authors have recognised E. merdarius auctt. (but see below) as a separate species from E. ramidulus ( Linnaeus, 1758) . Although Gauld (1973) stated that there are specimens intermediate between E. merdarius auctt. and E. ramidulus , and treated them as synonymous, we have seen no such specimens, and Gauld & Mitchell (1981) subsequently recognised the two as separate species. Differences in opinion regarding the status of E. merdarius auctt. and E. ramidulus have arisen because, although E. ramidulus has a distinctive identifying feature in the black-tipped metasoma, E. merdarius auctt. has no distinctive features, which we now know is because it is in fact a complex of similar species. Aubert (1966) had already separated off E. cerebrator Aubert, 1966 , a species subsequently recognised in several European countries but never sought in Britain. We have found E. cerebrator to be widespread in Britain and also discovered a third species in this complex, which had no name, described here as E. myricae sp. nov. The identity of E. merdarius has been ignored since Fitton (1984) designated a lectotype; both before and after Fitton’s (1984) lectotype designation, the name E. merdarius has frequently been applied to any Palaearctic Enicospilus with two discrete fore wing sclerites and lacking either a dark tip to the metasoma or dark patches on the mesosoma (i.e., excluding E. ramidulus and E. combustus ( Gravenhorst, 1829)) . Unfortunately, the lectotype of Ophion merdarius Gravenhorst, 1829 is the species that has generally been called E. tournieri , with the result that literature citations for E. merdarius do not refer to the species properly called E. merdarius (quite apart from the many misidentifications). Remarkably, for such a widespread species, there is only one potential synonym of E. merdarius auctt. (i.e., the larger species in the complex that includes E. cerebrator and E. myricae sp. nov.), namely Ophion adustus Haller, 1885 , synonymised under E. merdarius by Horstmann (1997) on the basis of the brief original description, which could equally refer to E. cerebrator or E. myricae sp. nov. The type specimen(s) of O. adustus cannot be found so, to stabilise usage of the name, we designate a neotype for O. adustus , meaning that the widespread, large species, usually referred to as Enicospilus merdarius , should be called Enicospilus adustus . Allowing for his misconception of E. merdarius , this is in line with the synonymy proposed by Horstmann (1997).