Cretaxenomerus vitreus Ulmer & Krogmann, 2023

UImer, Jonah M., Jansta, Petr, Azar, Dany & Krogmann, Lars, 2023, At the dawn of megadiversity - Protoitidae, a new family of Chalcidoidea (Hymenoptera) from Lower Cretaceous Lebanese amber, Journal of Hymenoptera Research 96, pp. 879-924 : 879

Cretaxenomerus vitreus Ulmer & Krogmann sp. nov.

Figs 2A , 11

Diagnosis.

Cretaxenomerus vitreus differs from all other species in the genus by the following combination of characters: fore wings broadly spatulate, with postmarginal vein about 2 × as long as stigmal vein (Fig. 2A ). All tarsi with manubrium broadly spatulate (Fig. 11F :man).

Description.

Female. Body length 1381. Body bilaterally damaged with some internal sclerite structures visible (Fig. 11A ). Most of the right part of the specimen is missing including both scapes and right pedicel, the whole mouth complex, entire right hind leg, right midcoxa, forecoxa and femur and base of right fore wing and entire hind wing. Metasoma damaged with only Mt2-5 and ovipositor sheats and ovipositor present. Body light brown in coloration, eyes red. Wings hyaline, speculum less pilose than wing disc. Head. Head broad, approximately 1.4 × as wide as long, posteromedially depressed. Eyes large, broadly oval, slightly taller than wide (Fig. 11A ). Ocellar triangle equilateral, ocelli raised and angled from head capsule; ocelli large (Fig. 11A ). No facial sulci or occipital carina present. Antenna length 805. All flagellomeres longer than broad, fu1-2 about 2.8 × as long as broad, fu3 2.0 × as long as broad (Fig. 11A ). Clava 1-segmented (Fig. 11B ). MPS present on all segments, extending beyond distal margin of segment, including on apical segment; MPS at least on fu1-4 in two rows. Pilosity sparse and uniform on all flagellomeres. Mesosoma length 480, pronotum medially obscured, with setal line along mesonotal margin. Mesoscutum 0.7 × length of mesosoma. Prepectus elongate and slender, overlapped anteriorly by lateral pronotal panel (Fig. 11D, E :pre). TSA complete across mesonotum (Fig. 11D :tsa). Mesopleuron large, 1.75 × as long as wide; transpimeral line present as narrow line. Metapleuron small, differentiated from mesopleuron by carina. Axillae not well defined. Mesoscutellum narrow and band-like, ⅕ length of mesoscutum. Frenum discernable as shift in scutellar sculpturing with marginal foveal rim, roughly ¼ length of mesoscutellum (Fig. 11D :fre). Dorsellum damaged. Propodeum ⅓ length of mesoscutum; supracoxal flange developed, but very narrow; propodeal spiracle ovoid (Fig. 11D :psp). Wings. Fore wing spatulate, 3 × longer than wide. Longest marginal seta length 40. Costal cell narrow. Submarginal vein broad and distally tapering, length 458. Cubital vein pigmented and tubular after intersection with basal vein for about length of basal vein then ephemeral distally, tubular portion equal in length to basal vein (Fig. 2A ). Basal vein strongly pigmented and broad, ⅖ length of entire cubital vein. Marginal vein strongly pigmented, ≈ ⅓ length of submarginal vein. Width of marginal vein ½ length of marginal seta. Stigmal vein broad, ½ length of postmarginal vein, oriented 90° relative to wing margin. Stigma spatulate with distinct uncus; uncal sensillae count 4 (Fig. 2A :uncs). Postmarginal vein elongate and tapering, equal in length to marginal vein. Hind wing approximately ½ length of fore wing, 16 × as long as wide. Longest marginal seta of hind wing longer than width of hind wing. Marginal vein of hind wing ½ length of hind wing. Legs. Hindlegs slightly longer than mid and fore legs which are equal in length (Fig. 11A ). Basitarsus of all legs roughly equal in length to tarsomere 2-4; basitarsal comb of fore leg absent (Fig. 11F ). Legs with sparse pilosity. Tarsal manubrium spatulate, as broad as tarsal claws (Fig. 11F :man). Metasoma. Only Mt2-5 preserved, all equal in length (Fig. 11C ). Medial longitudinal setal line present on all tergal segments, counting of setal lines retained in the amber indicate 6 tergal segments countable (Fig. 11C ). Ovipositor length 248. Ovipositor sheath equal in length to ovipositor, broadened along entire length; setae arising from surface of ovipositor sheath, margin bare.

Male. Unknown.

Material examined.

Holotype: female, Hammana / Mdeyrij , Caza Baabda , Mouhafazet Mount Lebanon; lower Barremian. In amber mounted in Canada Balsam. Deposited at Natural History Museum of the Lebanese University, accession/specimen number: 534C.

Type condition.

Face and mandibles absent from specimen. Mesosoma bisected and cleared with scleritic components visible on left side, internal components visible on right. Metasoma with first few terga present, and marginal setal line of other segments still present to indicate placement. Right hind leg with only distal tarsomeres remaining.

Etymology.

The specific epithet is the Latin word for ‘glassy’ or ‘transparent’ in regards to the unique taphonomy of the specimen that appears as though it were cleared.

Notes.

Damage to the specimen provides for a unique examination of both external and internal scleritic structures; however, damage to the abdomen has resulted in the loss of the terminal segments and syntergum. The lack of a multi-segmented clava is shared with Cretaxenomerus tenuipenna sp. nov.; however, the distinct difference in wing shape and venation separates these two specimens into distinct species.

Figures

Figure 2. Fore wing morphology and terminology A Cretaxenomerus vitreus, sp. nov. B Rotoita sp. (Baeomorphidae). av = anal vein; bc = basal cell; bv = basal vein; cc = costal cell; Cu 1 = cubital vein; hb = hyaline break; M + Cu = medio-cubital crossvein; mv = marginal vein; pas = parastigma; pmv = postmarginal vein; smv = submarginal vein; stv = stigmal vein; uncs = uncus.

Figure 11. Cretaxenomerus vitreus, holotype A lateral habitus B apical flagellomeres, lateral C metasoma, lateral D mesosoma, lateral E prepectus F fore leg. Scale bars: 500 µm (A); 100 µm (C-F).