Eurytoma shorthousei Zhang & Gates, 2017

Zhang, Y. Miles, Gates, Michael W. & Shorthouse, Joseph D., 2017, Revision of Canadian Eurytomidae (Hymenoptera, Chalcidoidea) associated with galls induced by cynipid wasps of the genus Diplolepis Geoffroy (Hymenoptera, Cynipidae) and description of a new species, Journal of Hymenoptera Research 61, pp. 1-29 : 3-7

Eurytoma shorthousei Zhang & Gates sp. n.

Figs 12 , 13 , 15 , 17 , 19 , 21 , 32

Etymology.

This species is named for Joseph D. Shorthouse, honoring his contribution to the understanding of Diplolepis galls and their associated inhabitants, as well as the collector of the type specimens.

Diagnosis.

This species differs from other eurytomids studied in the yellow or brown scape and tegula, with supraclypeal area strigose (Fig. 15 ). Propodeal spiracle with raised rim anteriorly (Fig. 19 ).

Holotype female.

Body length 3.2 mm. Color: Black except brown funicular segments, apices of procoxa and metafemur, metatibia excluding apex, and yellow scape, pedicel, pro- and mesotibia, mesofemur, apices of metatibia and metafemur, all tarsomeres 1-4, tip of ovipositor sheath, tegula, wing venation (Fig. 12 ).

Head. 1.3 × as broad as high, 2.5 × as broad as long in dorsal view, umbilicate punctured. Malar space 0.5 × eye height, malar carina present, raised in ventral half, becoming impressed line in dorsal half (Fig. 24 ). Gena entirely umbilicate punctured, minutely strigose posterad malar carina in ventral half, umbilicate posterad dorsal half (Fig. 24 ). Genal carina raised, forming blunt angle above oral fossa. Clypeus receding to median emargination and lower face strigose (Fig. 14 ), median longitudinal glabrous supraclypeal area (Fig. 14 ). Toruli positioned about ~1.5 torular diameters above lower ocular line. Lateral margin of antennal scrobes carinate, forming a raised lobe just above toruli. Intertorular projection approximately quadrate, dorsally truncate, with 2 rows of setae. LOL:OOL:POL is 1:1.4:2.3. Antennal segment ratios as: 55:15:3:25:20:18:15:15:35; pedicel chalice-shaped; funicular segments fusiform, subequal, with 2 rows of longitudinal sensilla and 2-3 rows adpressed setae; F1 lacking longitudinal sensilla in the basal third (Fig. 17 ).

Mesosoma. About 1.2 × as long as broad; notauli impressed, shallow. Epicnemium imbricate, flattened. Mesepisternum anterior to femoral depression, umbilicate; mesepimeron reticulate ventrally, striolate or smooth dorsally, with longitudinal rugae originating from the posterior margin. Precoxal tooth formed by raised adscrobal carina present in lateral view. Procoxa imbricate, lacking setation proximally, with oblique groove and S-like basal ridge. Metacoxa sparsely setose anteriorly and one row of setae on the posterior apical margin. Mesocoxal lamella absent. Lateral panels of propodeum and callus with umbilicate punctures distinctly delimited from median area by carinae forming irregular asetose cells, median furrow delimited, forming 1-2 rows of irregular foveae. Propodeal spiracle with raised rim anteriorly (Fig. 19 ). Forewing hyaline, setation dark, marginal vein as long as postmarginal vein, basal cell bounded by distinct basal and cubital setal lines, with sparse row setae parallel to submarginal vein; costal cell with single row of setae dorsally in apical half, speculum present and approximates width parastigma.

Metasoma. Gaster 1.5 × as long as mesosoma in lateral view. Length 81 (valvulae excluded), height 55, relative lengths of Gt1-4 measured along dorsomedial line: 8:9:20:25; syntergum 7. Smooth, anterior edge of gastral tergites microreticulate. Petiole with three separate protuberances, one dorsomedial and two anterolateral (Fig. 21 ). Gaster laterally compressed, oval shaped and convex in lateral view, ovipositor parallel to horizontal axis. Gt1-4 glabrate, Gt5-8 and apex of ovipositor sheaths setose. Posterior margin of Gt4 convex ventrally, straight dorsally. Posterior margin of Gt5 weakly emarginate.

Male.

Body length 3.0 mm. Color: Black, yellow and brown areas as described for female. Sculpture as described for female. Antennal segment ratios as: 52:14:3:36:27:31:27:27:42; funicular segments longer than wide, pedunculate, F2-F5 each with 3 irregular rows of appressed setae and two irregular rows of longitudinal sensilla; scape with ventral plaque in apical half (Fig. 13 ). Gaster 0.9 × as long as mesosoma in lateral view. Length 40, height 30, relative lengths of Gt1-4 measured along dorsomedial line: 7:10:34:10; syntergum 1. Petiole 2.0 × as long as broad, rugulose dorsally, mostly glabrous laterally and ventrally.

Variation.

Body length ranges from 2.5-3.2 mm in females, 1.7-3.0 mm for males. Occasionally, brownish area on anterior pronotum extends laterally onto collar.

Remarks.

This species was originally mistakenly identified as Eurytoma obtusilobae , described by Ashmead in 1885 based on four specimens, "bred from an unidentified cynips gall on Quercus obtusiloba [now stellata; post oak]" from Jacksonville, Florida. The only specimen remaining from this series is a female designated and labeled as a lectotype by Bugbee (1967). Bugbee (1951b) had previously redescribed " Eurytoma obtusilobae " based on the types and included 5 females and 10 males collected by J. C. Bridwell in Vienna, Virginia 1941 (ex Rhodites radicum on Rosa palustris ), but the latter belong to E. shorthousei . Only 4 pointed females and males could be located, though there is a gelatin capsule with 30 individuals from the same collecting event were not examined. Despite the fact that the lectotype from Florida was reared from cynips on post oak, Bugbee (1967: 460) refers to E. obtusilobae as being restricted to Diplolepis galls on rose. He speculated that Ashmead erred either in gall determination or incorrectly associated E. obtusilobae with oak. We suspect that E. shorthousei was incorrectly identified as conspecific with the E. obtusilobae type series, given the affinities of the latter (petiole, F1 MPS, propodeal spiracular rim, etc.) with oak associated Eurytoma , namely E. sphaera Bugbee. Further, it appears that E. obtusilobae falls within the range of variation of E. sphaera , a species associated with post oak throughout the eastern United States. Bugbee (1951b) incorrectly referred to a holotype and neotypes of both sexes (of E. obtusilobae ) deposited in the USNM and the Bugbee Collection (now at USNM).

The lectotype of E. obtusilobae is not conspecific with E. shorthousei as noted below although the two species do resemble each other in general habitus. They were confused due because sharing the supraclypeal striae and similar sculpture and coloration. They may be separated as E. shorthousei has medially notched clypeal margin (Fig. 14 ) versus un-notched (Fig. 15 ); MPS lacking in basal half F1 (Fig. 17 ) versus present (Fig. 16 ); propodeal spiracle with raised rim anteriorly (Fig. 19 ) versus not raised (Fig. 18 ); petiole anteriorly with three separate protuberances, one dorsomedial and two anterolateral (Fig. 21 ) versus anterodorsally produced as sharp lamina (Fig. 20 ). The three separate petiolar protuberances are commonly encountered in various forms across Eurytoma (and Eurytomidae ) so are seen in all Eurytoma treated herein. The petiolar production as in the E. obtusilobae lectotype is common in Eurytomidae and is germane given it is seen in other species attacking oak-associated cynipids (e.g. Quercus californica , Q. querciglobuli , and Q. studiosa ). However, much additional work across all Eurytoma associated with cynipids on oaks must be done before morphological trends are solidified.

Found at only one site in this study, E. shorthousei 's distribution is wide in North America given the specimens reported by Bugbee (1951b) as E. obtusilobae : VA, King George; MA, Gloucester; OR, La Grange; UT, Price; and CAN: Manitoba. The series Bugbee reported from New York and Minnesota could not be located. The series from Glencoe, Illinois is not E. shorthousei . The overall dearth of rearing records corresponds to the difficulty in locating their host galls induced by D. radicum , which are at ground level and often covered with soil and detritus ( Shorthouse 2010). Eurytoma shorthousei resembles E. discordans in gaster shape, but can be distinguished from the latter by coloration patterns and shape and size of female gaster.

Biology.

Reared from field populations of galls induced by Diplolepis radicum on Rosa carolina , R. palustris , and R. woodsii .

Material examined.

Holotype. Female, CANADA: British Columbia: Central Okanagan; Kelowna 2 km S.E. of Kelowna airport 49.952N - 119.381W; 344m; J.D. Shorthouse & R.G. Lalonde; 14/10/1999. ex Diplolepis radicum on Rosa woodsii (USNM) . Paratypes. 6F, 3M; 4M, 3F, same label data as holotype (all USNM); 2F, CANADA: British Columbia: Sandilands , 15-V-1967, J.C. Melvin, host gall on rose (CNCI) .

Distribution.

Collected in British Columbia and Manitoba (Fig. 32 ).

Figures

Figures 12 - 17. Eurytoma shorthousei sp. n. 12 Female habitus 13 Male habitus, arrow pointing to tegula 14 Clypeus 17 Female funicular segment 1. E. obtusilobae 15 Clypeus 16 Female funicular segment 1, arrow pointing to multiporous plate sensilla (MPS).

Figures 18 - 23. Eurytoma obtusilobae 18 Propodeum 20 Petiole, lateral view. E. shorthousei sp. n. 19 Propodeal spiracle 21 Petiole, dorsal view. E. discordans: 22 Head, anterior view 23 Head, posterior view.

Figure 32 - 37. 32 Known localities of Eurytoma shorthousei in Canada 33 Known localities of E. iniquus in Canada 34 Known localities of E. longavena in Canada 35 Known localities of E. discordans in Canada. 36. Known localities of E. imminuta in Canada 37 Known localities of E. spongiosa in Canada.

Figure 24 - 28. Eurytoma shorthousei 24 Face in lateral view. E. longavena 25 Propodeum 28 Female metasoma, lateral view. E. discordans 26 Female antenna 27 Female metasoma.