Echoes from the Cretaceous: new fossils shed light on the evolution of host detection and concealed ovipositor apparatus in the parasitoid wasp superfamily Orussoidea (Hymenoptera) Author Vilhelmsen, Lars Author Boudinot, Brendon Author Jenkins Shaw, Josh Author Hammel, Jörg U Author Perrichot, Vincent text Zoological Journal of the Linnean Society 2024 Zool. J. Linn. Soc. 2024-02-28 202 3 1 19 https://doi.org/10.1093/zoolinnean/zlae021 journal article 10.1093/zoolinnean/zlae021 0024-4082 14291325 † Kryptovelona carstengroehni Vilhelmsen and Perrichot, gen. et sp. nov. ( Figs 1–5 ) ZooBank registration : urn:lsid:zoobank.org:act: FCDEC20D-16ED-46AF-9866-4E792B0E7B1F (for Kryptovelona ); urn:lsid:zoobank.org:act: DCE94EBD-773F-438A-A441- A059C79149F8 (for carstengroehni ). Material examined: Holotype GPIH 5078 (CCGG no. 3811), a complete female preserved in a piece of Baltic amber dated as Late Eocene (Priabonian). Diagnosis: Ventral coronal teeth absent, fully developed ventral transverse longitudinal carina absent. Antennomeres 4 and 5 not conspicuously shortened, maxillary palp elongate, five-segmented. Median mesoscutal sulcus at most developed for a short distance anteriorly, notauli absent, mesoscutellum triangular, acute, raised compared to surrounding sclerites. Forewing vein 1r arises from approximately middle of pterostigma; vein 1r-Rs well developed, elongate, discal cell rectangular, proximal part not broader than distal part. Ovipositor internalized, extending into thorax, profurca with median groove and abdominal sterna with median apodemes for handling ovipositor. Description: Female (Fig. 1). Body length 6. 8 mm . Specimen generally well preserved; body with opaque film somewhat obscuring sculpture and pilosity, as well as original coloration; cracks in matrix around specimen also obscures certain features. Right hind tarsus cut off during trimming. Head: Ocellar corona narrow, distance between median ocellus and lateral coronal tooth subequal to ocellar width; ventral coronal teeth absent ( Figs 1A , 2B ). Dorsal transverse and longitudinal frontal carinae absent. Ventral transverse frontal carina not continuous medially, extending across toruli and laterally continuous with lateral carina of subantennal groove (Fig. 2A, B). Frons and vertex areolate-punctate, genae with scattered punctures; frons, vertex, and genae covered with fine, slender hairs (Fig. 2A, C). Internally, median and lateral frontal septa well developed. No conspicuous hairs just posteriorly of eyes. Postocular and occipital carinae absent (Fig. 2C). Lateral carina of subantennal groove low and short, not extending beyond posterior margin of eye. Tentorium with broad median and lateral lamellae on anterior arm, lamellae terminating some distance from anterior tentorial pit; tentorial bridge narrow, arched, with short anterior process; dorsal tentorial arms arise posteriorly on anterior arms, short, apparently do not reach head capsule (Fig. 2D). Antenna with 10 antennomeres, covered with short hairs; scapus elongate, cylindrical, slightly curved; combined length of antennomeres 4 and 5 longer than antennomere 6; antennomere 9 swollen subapically, as long as combined length of antennomeres 7 and 8, without carina laterally; antennomere 10 short, cylindrical, inserted subapically on antennomere 9 ( Figs 1C , 3C ). Labrum visible between opened mandibles, small, globose, with distinct ventrally directed hairs (Fig. 2A). Mandibles chisel-like, no teeth developed, with conspicuous distally pointing hairs laterally (Fig. 2A, B). Maxillary palps elongate, five-segmented, labial palps short, distal palpomere swollen (Fig. 2C). Thorax: Pronotum dorsally of equal length throughout, only shallowly incurved posteriorly; lateral sculpture obscured by pilosity/film (Fig. 4A, B). Prosternum mostly concealed by propleura, trapezoid, lateral margins converging anteriorly, discrimen and discrimenal lamella distinct; profurcal arms extend obliquely anteriorly from posterior corners of prosternum, profurcal bridge high and straight, with distinct median groove, not bent posteriorly (Fig. 5B, C). Fore coxa not expanded medially (Fig. 1C); fore femur without ventral carina; fore tibia swollen distally and subdivided by groove; fore tarsus with three tarsomeres, basitarsus elongate and terminating in spur overlapping tarsomere 2 (Fig. 3C). Mesoscutum finely punctate, mostly covered with short hairs, with scattered punctures laterally, median mesoscutal sulcus at most developed anteriorly, notauli absent, parapsides present laterally and transscutal articulation posteriorly (Fig. 4B, C); axillar flanges well developed; scutoscutellar sulcus well developed; mesoscutellum finely punctate, covered with hairs, acutely triangular posteriorly, raised and with carinate lateral margins; mesoscutellar arm raised, without pit anteriorly; mesonotum continuous posterior to mesoscutellum (Fig. 4C). Mesopleuron areolate—punctate laterally, mesosubalar carina present, mesepisternal carina absent; with mid-coxa subdivided, with distinct lateral carina. Metanotum metascutellum not developed, median metanotal carina not observed, lateral metanotal carina present, reaching posterior margin of metanotum; metapleuron with few hairs, mostly glabrous (Fig. 4A); hind coxae not especially hairy laterally, with rounded medioventral margin and well-developed posterolateral carina; hind femur without ventral carina or denticles ventrally; hind tibia with distinct pegs dorsally, longitudinal and ventral carinae not developed; apical hind tibial spurs short, of unequal length. Figure 1. † Kryptovelona carstengroehni gen. et sp. nov., female holotype (GPIH 5078, CCGG nº 3811). A, dorsal habitus. B, lateral habitus. C, ventral habitus. White arrow = vein 1-Rs; red arrow = vein cu-a; black arrows = coronal teeth; cx3 = hind coxa; dc = discal cell; fe3 = hind femur; n1 = pronotum; n2 = mesoscutum; pl1 = propleuron; pl2 = mesopleuron; pt = pterostigma; sc2 = mesoscutellum; tb1 = fore tibia. Figure 2. † Kryptovelona carstengroehni gen. et sp. nov., female holotype (GPIH 5078, CCGG nº 3811). A, C, photomicrographs. B, D, rendered from synchrotron scans. A, B, head, anterior view. C, head, lateroventral view. D, anterior view of tentorium. Red arrows = ventral transverse frontal carinae; white arrow = labrum; black arrows = coronal teeth; green arrows = maxillary palps; blue arrows = labial palp; ata = anterior tentorial arm; dta = dorsal tentorial arm; md = mandible; ltl = lateral tentorial lamella; mtl = median tentorial lamella; sc = scapus; teb = tentorial bridge. Wings: Forewing vein 2r-rs arise from approximately middle of pterostigma; vein 1-Rs well developed, elongate, discal cell rectangular, proximal part not broader than distal part; vein cu-a inserts on Cu1 close to middle of cell M (Fig. 1A). Hindwing venation cannot be observed. Abdomen: Dorsally covered by wings, hence obscuring structural detail via light microscopy; laterally with dense pilosity of short hairs. Tergum 1 and 2 coarsely areolate (Fig. 4C), postspiracular and subspiracular carinae on tergum 1 absent, median carina on tergum 2 absent; tergum 3–8 finely punctate. Median apodemes observed on several abdominal sterna (Fig. 5D); sternum 7 externally with narrow median part delimited laterally and projecting posteriorly. Tergum 9 covered with short hairs, without longitudinal carinae, smooth areas and depressions; internally, prominent anterior flange and chordate apodemes present. Ovipositor apparatus apparently not fully preserved (Fig. 5A); second valvifer with traces of ventral T 9-second valvifer muscles [muscle 6 in Vilhelmsen et al. (2001)] observable, possible base of ovipositor shaft with remains of processus medianus present; only parts of internalized ovipositor loop traceable, ventral/distal part extends anteriorly at least to mesofurca, manner of coiling in prothorax not observed; tip of ovipositor slightly protruding from tip of abdomen, third valvulae not visible. Composite tergum 10/ cercus triangular, not continuous medially. Figure 3. A, B, † Cretorussus vilhelmseni Jouault et al. 2021 , female holotype IGR.BU-020. C, † Kryptovelona groehni gen. et sp. nov., female holotype (GPIH 5078, CCGG nº 3811). Photomicrographs. A, distal part of antenna. B, fore tibia and tarsus. C, distal part of antenna and fore tibia and tarsus. Red arrow = tarsal spur; blue arrow = tibial spur (slightly displaced); green arrow = groove in fore tibia; A[x] = antennomere [x]; t[x] = fore tarsomere [x] (putative composite structures and structures distal to them in † Kryptovelona in italics, with homologues in † Cretorussus in brackets); tb1 = fore tibia. Figure 4. † Kryptovelona carstengroehni gen. et sp. nov., female holotype (GPIH 5078, CCGG nº 3811). A, B, photomicrographs. C, rendered from synchrotron scans. A, thorax, lateral view. B, thorax, lateral view. C, thorax and anterior abdomen, dorsolateral view. White arrow = metapleuron; red arrow = spiracle on 1st abdominal tergum; green arrows = transscutal articulation; blue arrow = parapside; yellow arrow = scutellar arm; n1 = pronotum; n2 = mesonotum; n3 = metanotum; pl1 = propleuron; pl2 = mesopleuron; sc2 = mesoscutellum; T1 = 1st abdominal tergum. Figure 5. † Kryptovelona carstengroehni gen. et sp. nov., female holotype (GPIH 5078, CCGG nº 3811). A, dorsal overview of extent of ovipositor inside the body; anterior to the top. B, profurca in posterior view. C, profurca in anterolateral view. D, posterior part of abdomen, dorsal internal view. All views rendered from synchrotron scans. Red arrows = ovipositor; black arrows = medain apodemes on abdominal sternum 6 and 7; green arrows = median groove on profurcal bridge; dl1 = prodiscrimenal lamella; pfb = profurcal bridge. Etymology: The genus name is a combination of krypto and velona , the Greek words for hidden and needle, respectively, alluding to the concealed ovipositor of the family. The species’ epithet honours Mr Carsten Gröhn (Glinde, Germany ) who generously made the type specimen available for study. Comments: Although both † Kryptovelona and † Baltorussus occur in Baltic amber, there are sufficient differences to justify recognizing them as separate genera. Besides, they do not group together in the phylogenetic analyses, where † Kryptovelona is placed closer to the clade comprising the majority of the extant taxa. The RoguePlots (Supporting Information, Figs S1 , S 4 ) flag a possible † Kryptovelona –† Baltorussus sister-relationship, but with lower probability than in the preferred Bayesian tree; other alternative placements of † Kryptovelona closer to the base of extant Orussidae have even lower support. The sculpture of the frons is highly diagnostic in † Baltorussus (Vilhelmsen and Zimmermann 2014: fig. 3A, B); this is not observed in † Kryptovelona . The latter has much denser pilosity over large areas of the body, in particular the dorsal part of the thorax. The median mesoscutellar sulcus is well developed in † Baltorussus , extending all the way to the transscutal articulation (Vilhelmsen and Zimmermann 2014: fig. 7), whereas it is absent in † Kryptovelona ; the notauli are also more developed in the former, extending approximately halfway to the articulation, whereas they are not developed in † Kryptovelona . In the forewing of † Kryptovelona , vein cu-a arises from approximately the middle of the discal cell; in † Baltorussus it is placed much closer to vein M.