Palaeorionis longicaudis gen. et sp. nov., by present designation and monotypy.

Named after “palaeo” (Greek for “ancient”) and the generic name of its similar extant genus, Orionis, which belongs to the subfamily Euphorinae. Gender: masculine.

Head (Fig. 1B, C) weakly transverse. Ocelli rather large and distinctly convex. Frons weakly convex. Eyes large, elongate-oval, glabrous. Face distinctly convex. Malar space very short; malar suture perhaps absent. Clypeus complete, distinctly convex (lateral view); hypoclypeal depression absent. Occipital carina distinct laterally, perhaps widely interrupted dorsally (Fig. 1B). Mandibles relatively small. Maxillary palpus very long (Fig. 1C), perhaps 6-segmented (medial segments hidden by mesosoma), its apical segment very long and slender, almost 25.0 times longer than its maximum width. Labial palpus short, with 4 segments, third segment very small, tiny, subglobular; apical (fourth) segment longest, knife-shaped, narrowed towards apex.

Figure 1. 

Palaeorionis longicaudis gen. et sp. nov. (holotype, female) A habitus, lateral view B head, latero-posterior view C head, antenna and mesosoma, lateral view D mesosoma without propodeum, lateral view E propodeum, lateral view F hind coxa G wings.

Antenna (Fig. 1A, C) long, slender, filiform, about 33-segmented. Scapus rather short and wide. Pedicel relatively small. First flagellar segment subcylindrical, without any transformations, much longer than its apical width, about as long as second segment. Apical segment pointed apically, but without spine.

Mesosoma (Fig. 1C, D, E). Sides of pronotum rugose upper and areolate below. Mesoscutum perhaps smooth, narrowly reticulate laterally. Notauli present, perhaps almost complete and shallow especially posteriorly. Scutellum distinctly convex. Prepectal carina present, sharp and distinct. Mesopleuron mainly smooth. Precoxal sulcus present, long, not deep, curved, distinctly crenulate-reticulate. Metascutum without dorsal tooth (lateral view). Propodeum dorsally almost straight in basal two-thirds, distinctly oblique sloped, starting from basal third, without lateral tubercles (in lateral view).

Wings (Fig. 1G). Fore wing rather narrow, pterostigma long and rather narrow. Radial (marginal) cell weakly shortened, narrow, about 4.5 times longer than its maximum width. Metacarpus (1-R1) 1.2 times longer than pterostigma. First medial abscissa (1-SR+M) present and curved. Present both radiomedial veins (2-SR and r-m). Second radiomedial (submarginal) cell short, pentagonal. Discoidal (first discal) cell not petiolate anteriorly, sessile. Recurrent vein (m-cu) postfurcal, subparallel to basal vein (1-M). First mediocubital vein (M+CU1) well sclerotised and distinctly sinuate. Nervulus (cu-a) postfurcal. Brachial (first subdiscal) cell open posteriorly; brachial vein (CU1b) absent. Transverse anal veins (1a and 2a) absent. Hind wing. Submedial (subbasal) cell short. First abscissa of mediocubital vein (M+CU) distinctly shorter than second abscissa (1-M).

Legs (Fig. 1A, F) slender and very long. Hind coxa elongate, without ventro-basal tubercle, as long as propodeum. Hind femur long and slender, 0.8 times as long as hind tibia. Hind tibia narrow basally, distinctly widened in apical 0.8. Hind tibial spurs relatively short, 0.3 times as long as hind basitarsus. Hind basitarsus about 0.8 times as long as second-fifth segments combined. Tarsal claw small and simple.

Metasoma (Figs 1A, 2) elongate, compressed behind petiole, entirely smooth, segments behind third one distinctly exposed posteriorly. First metasomal tergite very narrow entirely, fused ventrally almost entirely, tubular, smooth dorsally, with spiracles situated behind middle of petiole, without dorsope and laterope; 0.6 times as long as mesosoma and metasoma behind petiole. Suture between second and third tergites absent. Laterotergites (epipleura) of all segments not separated. Ovipositor long, weakly curved, compressed basally. Ovipositor sheath 1.2 times longer than the body length, almost twice longer than mesosoma, 1.1 times longer than fore wing (Fig. 1A).

Palaeorionis gen nov. is characterised by a long and tube-like petiole resembling a similar structure in some extant Euphorinae genera, especially Aridelus Marshall, 1887, Chrysopophthorus Goidanich, 1948, Orionis Shaw, 1987, Stenothremma Shaw, 1984, and Wesmaelia Foerster, 1863.

Palaeorionis gen. nov. differs from Orionis Shaw by having the last segment of the maxillary palpus very long and narrow (shorter and thicker in Orionis), discoidal (discal) cell of infuscate fore wing sessile (petiolate in hyaline fore wing in Orionis), second radiomedial vein (r-m) present (absent in Orionis), mediocubital vein (M+CU1) sinuate (straight in Orionis), brachial (subdiscal) cell long and rather narrow (short and wide in Orionis), petiole of metasoma smooth and without any carinae (at least partly sculptured and with lateral carinae in Orionis), and ovipositor sheath longer than metasoma (distinctly shorter in Orionis).

Palaeorionis gen nov. differs from Aridelus Marshall by having the last segment of maxillary palpus very long and narrow (shorter and thicker in Aridelus), mesosoma relatively long (short in Aridelus), hind coxa distinctly elongate-oval (shortly oval in Aridelus), mesosoma without areolate sculpture (entirely areolate in Aridelus), mediocubital vein (M+CU1) of fore wing sinuate (straight in Aridelus), hind femur relatively wide (narrow in Aridelus), metasoma rather compressed and with distinctly exposed apical segments (not compressed and retracted apical segments as in Aridelus), and ovipositor sheath longer than metasoma (very short and usually concealed inside of the metasoma in Aridelus).

The newly described genus also differs from Stenothremma Shaw by the last segment of the maxillary palpus very long and narrow (shorter and thicker in Stenothremma), mesosoma relatively long (short in Stenothremma), hind coxa distinctly elongate-oval (subglobal in Stenothremma), body without granulate sculpture (head, mesosoma and petiole densely granulate in Stenothremma), discoidal (discal) cell of infuscate fore wing sessile (petiolate in hyaline fore wing in Stenothremma), second radiomedial vein (r-m) present (often absent in Stenothremma), mediocubital vein (M+CU1) sinuate (straight in Stenothremma), brachial (subdiscal) cell long and rather narrow (short and wide in Stenothremma), petiole of metasoma smooth (petiole mainly granulate in Stenothremma), and ovipositor sheath longer than metasoma (distinctly shorter in Stenothremma).

The differences from the extant genera Wesmaelia and Orionis are summarized in Table 1.

Between the known fossil Euphorinae genera, Palaeorionis gen nov. is similar to Onychoura Brues, 1933 (with type species O. petiolata Brues, 1933) and Meteorites Brues, 1939 (with type species M. inopinata Brues, 1939), both from Baltic amber. This new genus differs from Onychoura by having malar area short (very long in Onychoura), mesosoma relatively elongated (very short in Onychoura), notauli present (perhaps absent in Onychoura), propodeum long (very short in Onychoura), radial (marginal) cell of fore wing weakly shortened (strongly shortened in Onychoura), recurrent vein (m-cu) distinctly postfurcal (interstitial in Onychoura), petiole of metasoma not swollen (swollen in Onychoura), and ovipositor longer than metasoma and without apical hook (distinctly shorter and with very slender apical hook in Onychoura). Palaeorionis gen nov. distinctly differs from Meteorites Brues by the last segment of maxillary palpus very long and narrow (much shorter and thicker in Meteorites), antenna long, about 33-segmented (short, 13–14-segmented in Meteorites), mesosoma relatively long, about twice longer than height (short, about as long as height in Meteorites), second radiomedial vein (r-m) of fore wing present (absent in Meteorites), nervulus (cu-a) and recurrent (m-cu) veins distinctly postfurcal (almost interstitial in Meteorites), petiole of metasoma not widened distally and almost straight (widened distally and distinct evenly curved in Meteorites), and ovipositor longer than metasoma and almost straight (distinctly shorter and strongly arcuate in Meteorites).

Holotype : Female, preserved in Lower Miocene Dominican amber (20–15 Ma), deposited in SMNS under collection number Do-2886-D. Well preserved, complete parasitoid inside amber piece (50 × 40 × 20 mm).

Figure 2. 

Palaeorionis longicaudis gen. et sp. nov. (holotype, female) A petiole, lateral view B anterior half of metasoma without petiole (gaster), lateral view C posterior half of metasoma, lateral view.

Female. Body length 7.7 mm; fore wing length 4.6 mm.

Head : Head not depressed, relatively high. Occiput at least weakly concave. Temple rather short. Transverse diameter of eye 3.7 times longer than temple (lateral view). Eye large, about 1.5 times as high as broad (lateral view). Malar suture perhaps absent. Malar space short. Clypeus without lower flange. Mandible rather short. Fourth segment of labial palpi the longest, 4.5 times longer than its maximum width, 1.7 times longer than second segment.

Antenna : First flagellar segment subcylindrical, 6.2 times longer than its apical width, as long as second segment; second segment 5.5 times longer than its apical with. Submedial segments about 2.5 times longer than their width. Penultimate segments short, 1.2–1.3 times longer than its width, 0.4 times as long as apical segment.

Mesosoma : Mesosoma relatively long, not depressed, its length about 2.0 times height. Neck of prothorax short. Mesoscutum highly and convex-roundly elevated above pronotum, its median lobe convex, weakly protruding forward, perhaps without anterolateral corners. Prescutellar depression (scutellar sulcus) invisible. Subalar depression shallow and sculptured. Mesopleuron widely smooth; metapleuron rugose.

Wings : Fore wing narrow, 3.9 times longer than its maximum width. Pterostigma about 5.0 times longer than width. Radial vein (r) arising behind middle of pterostigma, from basal 0.6. First (r) and second (3RSa) radial abscissae forming very obtuse angle. Second radial abscissa (3RSa) almost equal to first abscissa (r), 0.1 times as long as the straight third abscissa (3RSb), 0.2 times as long as the almost straight first radiomedial vein (2RS). Second radiomedial (submarginal) cell relatively narrow and short, 1.6 times longer than its maximum width, 0.6 times as long as the wide brachial (first subdiscal) cell. Brachial (first subdiscal) cell almost straight anteriorly. First medial abscissa ((RS+M) a) slightly curved. Recurrent vein (1m-cu) almost 0.5 times as long as first radiomedial vein (2RS), 0.3 times as long as basal vein (1M). Discoidal (first discal) cell rather long, 3.2 times longer than its maximum width. Nervulus (1cu-a) postfurcal, almost 2.0 times longer than distance from basal (1M) vein and nervulus (1cu-a). Parallel vein (2CUb) arising from posterior 0.2 of apical margin of brachial (second subdiscal) cell. Brachial (second subdiscal) cell long and wide. Hind wing relatively narrow. Radial (marginal) cell weakly widened basally and narrowed apically, without additional transverse vein (r). Nervellus (cu-a) present, oblique. Submedial (subbasal) cell short. First abscissa of mediocubital vein (M+CU) 0.6 times as long as second abscissa (M).

Legs : Fore trochanter almost twice longer than trochantellus. Fore tarsus almost as long as fore tibia. Hind coxa 2.0 times longer than maximum width, 0.7 times as long as petiole. Hind femur 6.5 times longer than width. Hind tarsus slender, 0.8 times as long as hind tibia. Second segment of hind tarsus 0.5 times as long as basitarsus, almost 2.0 times longer than fifth segment (without pretarsus).

Metasoma : Metasoma 1.2 times longer than head and mesosoma combined. First metasomal tergite 9.6 times longer than medial high (at spiracles level), tergite ventrally fused in basal 0.8. Lateral suture between second and third tergites present, but dorsal suture absent. Second and third tergites combined 0.7 times as long as following tergites. Hypopygium short, obtuse distally, strongly retracted below under metasoma, almost glabrous.

Sculpture : Vertex and temple mainly smooth. Hind coxa and femur smooth. Metasoma entirely smooth. Hind tibia with rather dense and short semi-erect setae, its length 0.2–0.3 times maximum width of tibia.

Colour : Body almost entirely black or dark brown. Antenna mainly light brown. Labial palpi light brown; maxillary palpi dark reddish brown, but at least apical segment brownish yellow. Legs mainly dark brown, all tibiae basally yellow at short distance. Ovipositor sheaths light brown, infuscate apically. Fore wing almost entirely distinctly infuscate, paler basally and apically, with distinct hyaline transverse stripe under base of pterostigma. Pterostigma mainly dark brown, pale brown in basal fifth.

Male. Unknown.

Named from Latin “longus” (= long) and “caudus” (= tail, ovipositor) because this taxon has the longest known ovipositor of all fossil Euphorinae taxa.