Research Article
Print
Research Article
A new fossil euphorine genus and species (Hymenoptera, Braconidae) with the longest known ovipositor from Dominican amber
expand article infoSergey A. Belokobylskij, Tomáš Hovorka§|
‡ Zoological Institute Russian Academy of Sciences, St. Petersburg, Russia
§ Department of Entomology, National Museum, Prague, Czech Republic
| Charles University, Prague, Czech Republic
Open Access

Abstract

A new genus and species of the braconid subfamily Euphorinae, Palaeorionis longicaudis gen. et sp. nov., is described and illustrated from Miocene Dominican amber. This new genus is characterised by the long and tube-shaped petiole, presence of both radiomedial (2-SR and r-m) veins on the infuscate fore wing and long ovipositor.

Keywords

Aridelus, description, fossil, Miocene, Orionis, ovipositor, petiole, Stenothremma

Introduction

The subfamily Euphorinae is one of the most diverse groups of koinobiont parasitoids of the family Braconidae, which are known to attack larval, nymphal, and adult stages of hosts from the insect orders Orthoptera, Hemiptera, Psocoptera, Raphidioptera, Neuroptera, Coleoptera, Lepidoptera and Hymenoptera (Tobias 1965, 1966; Shaw 1985; Yu et al. 2016).

Most of the known fossil euphorine taxa have been described from amber (Brues 1933, 1937, 1939; Tobias 1987), though a few of its representatives are known from compression fossils (Belokobylskij 2014). Aside from the relatively common fossil parasitoids of coleopteran and lepidopteran larvae from the genus Meteorus Haliday, 1835 of the tribe Meteorini, parasitoids of hemipteran nymphs and coleopteran and hymenopteran adults have been also discovered. There are species of the genus Leiophron Nees, 1819 (Euphorus Nees, 1834) (Euphorini) parasitods of the hemipteran nymphs, the genera Pygostolus Haliday, 1833 (Pygostolini), Parasyrrhizus Brues, 1933 (Centistini), Microctonus Wesmael, 1835, and perhaps Onychoura Brues, 1933 and Meteorites Brues, 1939 (Perilitini) (Brues 1933, 1937, 1939) are known to parasitize coleopteran and hymenopteran hosts. The extinct genus Elasmosomites Brues, 1933 actually belongs to the isolated euphorine tribe Neoneurini, whose members are parasitoids of the ant workers (Brues 1933; Belokobylskij et al. 2021). Additionally, two peculiar genera that are only known from the Baltic amber have unknown biologies, namely Oncometeorus Tobias, 1987 from the monotypic tribe Oncometeorini and Prosyntretus Tobias, 1987 from the Prosyntretini (Tobias 1987).

This study provides an illustrated description of the female of a new euphorine genus and species from the Miocene Dominican amber that is characterised by the long tube-shape petiolate first metasomal tergite and long ovipositor.

Methods

Dominican amber (Lower Miocene age; 20–15 Ma) is the fossilized resin of the leguminose tree Hymenaea protera Poinar, being mostly transparent and often containing a high number of fossil inclusions, and it has been collected in various sites within the Dominican Republic (Iturralde and Macphee 1996; Rasnitsyn and Quicke 2002).

During the present study, fossil braconid specimen were examined using a Leica M205 C stereomicroscope (Microsystems, Wetzlar, Germany). Photographs were obtained using a Keyence VHX-5000 (Mechelen, Belgium) digital microscope under suitable magnifications. Subsequent image processing was performed using Helicon Focus Pro 7 software. Final plates were prepared in Adobe Photoshop CS6.

The terminology employed for morphological features, sculpture and body measurements follows Belokobylskij and Maeto (2009). Wing venation nomenclature also follows Belokobylskij and Maeto (2009), with the terminology of van Achterberg (1993) shown in parentheses.

The material used for this study is deposited in the collection of the Stuttgart Museum of Natural History, Germany (SMNS).

Results

Systematic part

Class Insecta Linnaeus, 1758

Order Hymenoptera Linnaeus, 1758

Family Braconidae Nees, 1811

Subfamily Euphorinae Foerster, 1863

Palaeorionis gen. nov.

Figs 1, 2

Type species

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

Etymology

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

Description

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).

Comparative diagnosis

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.

Table 1.

The differences between the Palaeorionis gen nov. and two similar recent genera (Wesmaelia Foerster and Chrysopophthorus Goidanich).

Genus Palaeorionis gen. nov. Wesmaelia Chrysopophthorus
Character
1. Last segment of the maxillary palpus very long and narrow shorter and thicker shorter and thicker
2. Pedicel of antenna distinctly enlarged, more than half as long as scape short, much less than half of the length of scape distinctly enlarged, about half as long as scape
3. Mesosoma relatively long short short
4. Colour of fore wing infuscate hyaline hyaline
5. Second radiomedial vein (r-m) of fore wing present absent present
6. Mediocubital vein (M+CU1) of fore wing sinuate straight straight
7. Discoidal (discal) cell of fore wing sessile petiolate petiolate
8. Hind coxa distinctly elongate-oval weakly oval weakly oval
9. Hind femur widened narrow narrow
10. Metasoma rather compressed and with distinctly exposed apical segments not compressed and with retracted apical segments not compressed and with retracted apical segments
11. Ovipositor sheath longer than metasoma very short and usually concealed inside of metasoma distinctly shorter than metasoma

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).

Palaeorionis longicaudis sp. nov.

Figs 1, 2

Type material

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.

Description

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.

Etymology

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

Discussion

The fossil braconid taxa from the subfamily Euphorinae are relatively common in the Paleogene in comparison to the members of some other braconid subfamilies. They were often attributed as representatives of extant genera, however various of these fossil taxa actually belong to peculiar extinct taxa, namely Elasmosomites Brues, Meteorites Brues, Oncometeorus Tobias, Onychoura Brues, Parasyrrhizus Brues and Prosyntretus Tobias (Brues 1933, 1937, 1939; Tobias 1987, Belokobylskij 2014, Belokobylskij et al. 2021). These euphorine genera were recorded from the inclusions found in the Baltic and Canadian ambers (Brues 1933, 1939, 1937; Tobias 1987) and were placed in the tribes Meteorini, Oncometeorini, Perilitini, Centistini, Euphorini, Prosyntretini and Neoneurini.

The tubular petiole of the mesosoma is practically unknown from previously recorded fossil euphorine taxa. In this situation, the genus Palaeorionis gen nov., is the first extinct genus having such long tube-shaped petiole. Perhaps only Onychoura Brues, 1933 from Baltic amber possessed a petiole with similar structure, but it is much shorter and thickened towards the apex. The new genus is also well characterised by the distinctly infuscate fore wing having submedially only a single narrow transverse subhyaline stripe, very long ovipositor (much longer than metasoma), and distinctly thickened tibia of the hind leg. This character combination is unknown in all previously recorded amber euphorine genera.

The host of Palaeorionis longicaudis gen. et sp. nov. is unclear. However, based on available characters such as a long ovipositor and presence of both radiomedial veins (2-SR and r-m) in the fore wing this genus likely belongs to the tribe Meteorini, whose members are known to be endoparasitoids of coleopteran and lepidopteran larvae. Regarding its long ovipositor, this species might have been a parasitoid of some concealed hosts such as wood-boring beetles.

Acknowledgements

Authors are thankful to Stuttgart Museum of Natural History (Germany) for the loan of the amber piece. We are also thankful to Dr Julia Stigenberg (Stockholm, Sweden), Prof Donald J. Quicke for their useful consultations, Dr Petr Janšta and Jonah Ulmer for their useful tips and final corrections.

The authors are very thankful to Dr Alejandro Zaldívar-Riverón (UNAM, México) and Prof Cornelis van Achterberg (Naturalis, Leiden, The Netherlands) for their very useful comments on the first version of the manuscript.

This study was supported by The Charles University Grant Agency (GAUK), project No. 375421 (TH) and performed as a part of the State Research Project No 122031100272-3 (SAB).

References

  • Belokobylskij SA (2014) Family Braconidae. In: Antropov AV, Belokobylskij SA, Compton SG, Dlussky GM, Khalaim AI, Kolyada VA, Kozlov MA, Perfilieva KS, Rasnitsyn AP (Eds) The wasps, bees and ants (Insecta: Vespida = Hymenoptera) from the insect limestone (Late Eocene) of the Isle of Wight, UK. Earth and Environmental Sciences Transactions of the Royal Society of Edinburgh 104 (3–4), 335–446. https://doi.org/10.1017/S1755691014000103
  • Belokobylskij SA, Dubovikoff DA, Manukyan AR, Zharkov DM (2021) Braconid parasitoids of ants (Hymenoptera, Braconidae, Euphorinae, Neoneurini) from Baltic amber with a discussion of records of fossil larvae parasitizing ant workers. Journal of Hymenoptera Research 84: 29–43. https://doi.org/10.3897/jhr.84.67749
  • Belokobylskij SA, Maeto K (2009) Doryctinae (Hymenoptera, Braconidae) of Japan. Fauna mundi, Vol. 1, Warszawa, Warshawska Drukarnia Naukowa, 806 pp. https://doi.org/10.3161/067.058.0107
  • Brues CT (1933) The parasitic Hymenoptera of the Baltic amber. Bernstein Forschungen 3: 4–178.
  • Brues CT (1937) Superfamilies Ichneumonoidea, Serphoidea, and Chalcidoidea. In: Carpenter FM, Folsom JW, Essig EO, Kinsey AC, Brues CT, Boesel MW, Ewig HE (Eds) Insects and arachnids from Canadian amber. University of Toronto Studies. Geological Series 40: 27–44.
  • Shaw SR (1985) A phylogenetic study of the subfamilies Meteorinae and Euphorinae (Hymenoptera: Braconidae). Entomography 3: 277–370.
  • Tobias VI (1965) Generic grouping and evolution of parasitic Hymenoptera of the subfamily Euphorinae (Hymenoptera, Braconidae). I. Entomologicheskoe Obozrenie 44: 841–865. [In Russian]
  • Tobias VI (1966) Generic grouping and evolution of parasitic Hymenoptera of the subfamily Euphorinae (Hymenoptera, Braconidae). II. Entomologicheskoe Obozrenie 45: 612–33. [In Russian]
  • Tobias VI (1987) New taxa of Braconidae from Baltic amber (Hymenoptera). Entomologicheskoe Obozrenie 66(4): 845–859. [English translation: Entomological Review 67(4): 18–32.] [In Russian]
  • van Achterberg C (1993) Illustrated key to the subfamilies of the Braconidae (Hymenoptera: Ichneumonoidea). Zoologische Verhandelingen 283.
  • Yu DS, van Achterberg C, Horstmann K (2016) Taxapad 2016. Ichneumonoidea 2015. Nepean, Ottawa, Ontario. [database on flash-drive]