Conostigmus canadensis ( Ashmead, 1888 )

Trietsch, Carolyn, Mikó, István, Ezray, Briana & Deans, Andrew R., 2020, A Taxonomic Revision of Nearctic Conostigmus (Hymenoptera: Ceraphronoidea: Megaspilidae), Zootaxa 4792 (1), pp. 1-155 : 33-35

Conostigmus canadensis ( Ashmead, 1888)

Figs. 18 , 19

Species Comments and History. Ashmead (1888) described this species from a single female specimen as part of the genus Eumegaspilus , characterized by the females being wingless or having reduced wings. Ashmead (1893) redescribed the species, transferred it to Megaspilus and designated C. erythrothorax as the type species for Eumegaspilus . For C. canadensis, Ashmead keyed out the female, distinguishing it from other females based on its reduced wings, cuticular sculpture and color differences (1893).

Harrington (1900) recorded four more female specimens of C. canadensis collected with Harrington’s C. ottawensis specimens, noting that these four specimens might be a variety of C. ottawensis . We found these four specimens at the CNC, all bearing labels reading “ Megaspilus canadensis = ottawensis Ashm. || W. H. Harrington Collection”. Harrington (1900) also recorded the existence of a fifth specimen, which we found at the CNC, bearing only a determination label reading “ Megaspilus canadensis ”. All of these specimens are females in poor condition (damaged and badly glued, obscuring characters) and none were collected with the type. These specimens may not match each other, let alone the type of C. canadensis . One female had the preoccipital furrow not reaching the ocellar triangle (the type has the preoccipital furrow ending inside the ocellar triangle). Further work must be done to verify whether these specimens are the same species. These five specimens were not databased.

Kieffer (1909) transferred C. canadensis from Megaspilus to the genus Conostigmus . Kieffer (1914) then redescribed and keyed out the female, distinguishing it from other female Conostigmus by its reduced wings and coloration. Muesebeck and Walkley (1951, 1956) reconsidered C. canadensis as the type of Eumegaspilus and consider Eumegaspilus as a synonym of Conostigmus . Muesebeck and Walkley (1956) justified this by noting that C. erythrothorax was not in the original description of the genus. Dessart and Cancemi (1987) consider C. canadensis to be the type species of the subgenus Eumegaspilus . They also note that C. canadensis is probably cosmopolitan ( Dessart and Cancemi, 1987).

The female type is present at the USNM in the same condition as noted in Masner and Muesebeck (1968). Dessart and Cancemi (1987) suggested that this species could be synonymous with C. lativentris . While this specimen bears a strong resemblance to the female types of C. lativentris at the NHMUK and HNHM (wings reduced or absent, sternaulus present and elongate, facial pit present, postocellar carina present, preoccipital furrow present, median process on the intertorular carina present and acute, axillular carinae present), there are differences in the sculpturing. The type at the NHMUK has foveolate sculpturing on the frons and mesosoma; the type at the HNHM does not have foveolae but has rugose sculpturing present on the frons and mesosoma; and the type at the USNM has smooth sculpturing on the frons and mesosoma. Though all three specimens have rugose sculpturing on the apex of the head around the ocelli, the types at the HNHM and NHMUK have crenulate sternauli, whereas the type at the USNM has a smooth sternaulus. It is possible that these differences could be attributed to size, nutrition and other factors, and that they could be the same species, but further evidence is needed to confirm this. Conostigmus lativentris is also only known from the Palearctic, whereas C. canadensis is only known from the Nearctic.

Both C. canadensis and C. lativentris are only known from female specimens. Until the discovery of males or more females, or until the five female specimens at the CNC can be further studied, we cannot confirm if C. canadensis and C. lativentris are the same species. We consider them separate species at this time, and we regard C. canadensis as a species inquirenda.

Material Examined. Lectotype female: CANADA: USNMENT01339753 ( USNM).

Figures

FIGURE 18. Conostigmus canadensis (Ashmead, 1888) female lectotype (USNMENT01339753). A. Lateral habitus. B. Anterior view of the frons.

FIGURE 19. Conostigmus canadensis (Ashmead, 1888) female lectotype (USNMENT01339753). A. Lateral view. B. Dorsal view. Abbreivations: pronotum (prn).