Cretaxenomerus curvus 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 curvus Ulmer & Krogmann sp. nov.

Figs 3B , 8 , 9 , 16B

Diagnosis.

Female. Females differ from those of all other species within the genus by the following combination of characters: Syntergum hinged at joint with elongated Mt7, reaching more than ¾ length of ovipositor sheath (Fig. 8D :Mt8+9); fore wing with postmarginal vein about equal in length to stigmal vein and cubital vein extending beyond tip of postmarginal vein (Fig. 8F ). Male. Same as female except flagellomeres all as wide as long; clava 2-segmented (Fig. 9B ).

Description.

Female. Body length 1314 (HT) - 1407 (PT). Overall body color black with a blue sheen on the gena of HT when examined at certain angles except tegulae, legs excluding coxae, and second half of ovipositor sheath dark brown, tip of ovipositor sheath light brown, and with legs almost black. Wings hyaline except fore wing slightly brownish in HT (possible artifact) and partly brownish in PT 881B; with sparser pilosity proximally on wing surface. Head, mesosoma and metasoma coriaceous to alutaceous except areolate posterior part of mesoscutellum and propodeum. Head ovate, 1.5 × as wide as long (Fig. 8E ). Vertex and temple of head curved strongly, back of head concave, closely associated with mesosoma. Temple about 0.3-0.25 × as long as eye length. Eye broadly oval, almost as long as high. Ocellar triangle equilateral, POL=LOL=OOL. Malar sulcus faint, but present. Shallow internantennal projection (Fig. 8E :iap). Toruli closer to inner margin of eye than each other and very close to dorsal margin of clypeus, well below center of eye, hence lower face short. Clypeus dorsally with raised rim, inwardly inflexed, with row of setae just below dorsal clypeal margin (Fig. 8E ). Anterior tentorial pits situated well below dorsal margin of clypeus. Dentition 3:3, mandibles on different plane from face (Fig. 8E ). Maxillary palp 3 segmented, distal segment longer than basal segment (Fig. 8E ). Antenna length 637 (HT)-671 (PT). Antenna 14-segmented. Radicle raised from face. Fu1-2 at least 2 × as long as wide. Clava 2-segmented (Fig. 8C ); clava 1.5 × as long as wide. MPS present on all flagellomeres with single row on each segment; MPS on terminal segment not extending beyond tip. All segments uniformly pilose (Fig. 8C ). Mesosoma length 380 (PT)-401(HT). Pronotum with bristle on posterolateral corner. Mesoscutum obscuring pronotum medially in dorsal view. Lateral part of prepectus slender and straight, dorsally covered by posteriormost corner of lateral pronotum, slightly broadened ventrally (Fig. 16A :pre). Mesonotum large, roughly 2/3 × as long as mesosoma. Notauli present and simple impressions. Mesopleuron 2 × as high as long in lateral view (Fig. 8 ,B). Suture present between meso- and metapleuron (Fig. 8A ). Transcutal articulation present and complete. Axillae reduced, axillulae extending further anterior than posterior edge of mesonotum (Fig. 8B :axl). Mesoscutellum short, about 1/5 length of mesonotum. Dorsellum band like. Propodeum strongly sloped. Wings. Fore wing 2.4 × (PT)-2.7 × (HT) as long as wide. Pilosity sparse in basal part of wing relative to disc (Fig. 8F ). Basal cell dorsally with one median row of hairs only. Longest marginal seta of fore wing 38. Cubital vein extending beyond length of postmarginal vein, length 377 (Fig. 8F ). Basal vein short, length 43. Submarginal vein length 342. Marginal vein strongly sclerotized and broad, length 96, width 29; marginal vein with 6 marginal sensillae present. Stigmal vein present, equal in length to postmarginal vein, at 45° angle with wing margin (Fig. 8F ). Uncus present; 5 uncal sensillae in cluster. Postmarginal vein very short, about 0.25 × as long as marginal vein (Fig. 8F ). Hind wing elongate and narrow 6.8 × as long as wide. Hamuli count 3, proximal hamular hook longer than other 2. Hamuli and venation of hind wing only extend ⅓ length of hind wing. Legs. Hind femur slightly broadened medially (Fig. 8A ). Fore tibia with curved clefted spur. Hind tibia with two spurs, shorter spur about 0.75 × as long as longer one. Basitarsus of fore leg ventrally curved; basitarsal comb present, bristles of comb very short (Fig. 8A ). Metasoma length 407, nearly equal in length to mesosoma. Six (Mt2-7) tergal segments and syntergum (Mt8+Mt9) countable, except the Mt3-7 all roughly equal in length from lateral view (Fig. 8A ). Six sternal segments visible. Hypopygium flanged, extending beyond Mt7. Syntergum articulating with Mt7 and covering ovipositor sheaths dorsally, syntergum length 273, Mt7 length 51 (Fig. 8A, D ). Ovipositor 1.2 × as long as metasoma; tip of ovipositor with 5 teeth; ovipositor sheaths stalk-like at base, distally spatulate with sensillae along margin, sheaths approximately equal in length to syntergum (Fig. 8D :3v). Male. Similar to female except the head is not as long (Fig. 9A ). Interantennal process reaching over the ⅔ of eye height, antenna with only Fl1 about as 2 × as long as wide (Fig. 9B ). Clava 2-segmented (Fig. 9B ). Postmarginal vein slightly longer than stigmal vein (Fig. 9D ). Male genitalia extended; digitus with single digital spine (Fig. 9C :dig)

Specimens 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: 874 D. Locality information and depository of paratypes same as for holotype (Female-881B,146U; Male-1614FA).

Type condition.

Right antenna of holotype with terminal 3 segments missing. The amber piece of the holotype included a single inclusion of a Ceratopogonidae ( Diptera ).

Etymology.

The specific epithet is derived from the Latin ‘curvus’ meaning curved or bent, in regards to the articulation of the syntergum of the species.

Notes.

The metasoma of paratype specimen 146U is damaged, preventing examination of the syntergum, however the wing venation and head shape place it as C. curvus . This is the only species described based on both sexes which provides some insight into the putative sexual dimorphisms within the genus. Notably, the variation in antennal shape and claval size which is a prolific form of dimorphism within extant chalcids. The female of C. curvus has a clear clava with multiple claval segments relative to the male which has all flagellar segments relatively stout and uniform with only the partial fusion of the terminal segments indicating a clava.

Figures

Figure 3. Antennal morphology A Protoita noyesi, sp. nov. B Cretaxenomerus curvus, sp. nov. C Rotoita basalis (Baeomorphidae). cln = claval segment n; fun = funicular segment n; mps = multiporous plate sensilla; pe = pedicel; sc = scape.

Figure 8. Cretaxenomerus curvus, holotype (874 D) A lateral habitus B mesosoma, lateral C antenna, lateral D ovipositor complex and terminal abdominal segments E head, lateroventral F fore wing. Scale bars: 500 µm (A); 150 µm (F); 100 µm (B-E). iap = interantennal process; lcl = lateral clypeal line; Mt 8 + 9 = syntergum.

Figure 9. Cretaxenomerus curvus, male paratype (1614 F) A dorsal habitus B antenna, lateral C male genitalia, ventral D fore wing venation. Scale bars: 250 µm (A); 100 µm (B, D); 50 µm (C). phb = phallobase.

Figure 16. Prepectus of Protoitidae A Cretaxenomerus curvus, mesosoma, lateral B Protoita noyesi, mesosoma, ventrolateral. Scale bars: 100 µm (A, B).