Eourocerus anguliterreus Archibald & Rasnitsyn, 2022

Archibald, S. B. & Rasnitsyn, A. P., 2022, The early Eocene Eourocerus anguliterreus gen. et sp. nov. (Hymenoptera, Siricidae) from Republic, Washington, Zootaxa 5105 (2), pp. 289-295 : 290-291

Eourocerus anguliterreus Archibald & Rasnitsyn , new species

Figure 1 , 2B

Diagnosis. As for genus.

Material. Holotype forewing SRUI-99-97-08A, B, collected by Karl Volkman at Republic A0307 , April 15, 2015, on a slab about 20 X 60 cm with wings of three taxa of Cercopoidea (Hemiptera), a pair of beetle elytra (Coleoptera), a march fly ( Plecia Wiedemann, 1828 , Bibionidae , Diptera ), several more fragmentary insects, an unidentified angiosperm leaf, a leaf of Macginitiea (Platanaceae) , Metasequoia and Glyptostrobus or Taxodium foliage ( Taxodiaceae ), and a Koelreuteria fruit ( Sapindaceae ); housed in the collections of the Stonerose Interpretive Center, Republic, Washington, USA .

Description. Forewing, sex unknown. Apex blunt; length estimated ca. 24 mm complete, maximum width estimated ca. 8 mm complete; membrane infuscate, more darkly so near pterostigma, in cell C, anal cells; longitudinal corrugation preserved in cells 2r, 3r, 2rm, 3rm, 4rm, 2mcu, 3mcu, apical area, longitudinal/transverse corrugation in distal portion of cell 1cua; Sc fragmentarily preserved in approximately mid C space; pterostigma narrow; 2rrs joins pterostigma more than its length from pterostigma end; cells 1r, 1mcu joining briefly forming very short Rs+M; 1-M almost straight; 2r-m joins Rs in cell 3r, about half way between 2r-rs, 3r-m; cell 3rm longer than high (width twice length of 3r-m, about 1.3 length of 2r-m); Rs, R1 join, closing cell 3r; 2m-cu joins M at basal third of cell 3rm; cells 2rm, 2mcu 3.5 times longer than high; Cu1 absent, with characteristic bend in at M+Cu, M; adventitious crossvein in cell 2cua; crossvein a basal to cu-a; 2A+3A adjacent posterior margin about half to third length of cell 1a (basal portion missing); stub of 3A not detected; nygmata not detected.

Etymology. The specific epithet is formed from the Latin anguli terra, meaning “corner land”, referring to exposure A0307 (“the corner lot”).

Range and age. Tom Thumb Tuff Member of the Klondike Mountain Formation at Republic, Washington, USA, exposure A0307; Ypresian.

Figures

FIGURE 1. Holotype Eourocerus anguliterreus gen. et sp. nov., SRUI-99-97-08A, B. A, photograph of part, SRUI-99-97- 08A; B, drawing from part and counterpart. Both to scale, 5 mm. Cell names in italics, vein names in Roman font.

FIGURE 2. Comparison of forewing shapes of A, Urocerus albicornis (Fabricius, 1781) drawn from Schiff et al. (2012) figure B1.71, and; B, Eourocerus anguliterreus. For shape comparison, they are to different scales, aligned to the branching of M+Cu and 3r-m.