Research Article |
Corresponding author: Serguei A. Simutnik ( simutnik@gmail.com ) Academic editor: Petr Janšta
© 2021 Serguei A. Simutnik, Evgeny E. Perkovsky, Mykola R. Khomych, Dmitry V. Vasilenko.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Simutnik SA, Perkovsky EE, Khomych MR, Vasilenko DV (2021) First record of the Sulia glaesaria Simutnik, 2015 (Hymenoptera, Chalcidoidea, Encyrtidae) from Rovno amber. Journal of Hymenoptera Research 88: 85-102. https://doi.org/10.3897/jhr.88.75941
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Sulia glaesaria Simutnik, 2015 (Chalcidoidea, Encyrtidae), originally described from late Eocene Danish amber, is reported in coeval Rovno amber. A revised diagnosis of this genus is provided based on the new specimen and high-resolution photomicrographs of the holotype. Some character states, such as a short radicle, clypeus with long lateral margins, the presence of a strigil and basitarsal comb, spur vein of the hind wing, costal cell of hind wing along entire marginal vein with single line of long setae, and almost vertical syntergum with abruptly reflexed extension apically are reported in this species for the first time.
Acropleural sulcus, acropleuron, Danish amber, Eocene, fossil Encyrtidae, syntergum
Our research on several amber collections shows that the Encyrtidae is one of the most widespread families of Chalcidoidea in Eocene ambers (
Sulia glaesaria Simutnik, 2015 was described from late Eocene Danish amber (
The earliest known Encyrtidae include one female and four males ascribed to five different genera from middle Eocene Sakhalinian amber (
Ukrainian Rovno amber (33.9–37.8 Mya) is coeval with Baltic and Danish ambers from which L. janzeni and S. glaesaria were described.
The localities and composition of the Rovno amber fauna were recently characterized in a series of reviews by
Nearly all studied Rovno amber inclusions from Rovno were collected from Klesov and the Horyn River Basin (
Danish amber is much understudied (
The amber piece containing the new specimen of S. glaesaria was found near the village of Voronki in the Vladimirets District (basin of Styr River), Rovno Region, Ukraine. It is housed in the collection of the Schmalhausen Institute of Zoology of the National Academy of Sciences of Ukraine, Kiev (SIZK). Danish amber containing the holotype is reddish and not very transparent. The sample from Rovno amber is yellow and clear (Fig.
Sulia glaesaria, females A pieces of amber containing the inclusions: holotype in Danish amber, deposited in ZMUK (red) and new specimen from Rovno amber, deposited in SIZK (yellow) B head, holotype, ventrofrontal C habitus, holotype, right lateral (acs – acropleural sulcus, cly – clypeus; hyp – hypopygium, pre – prepectus).
The condition of the Rovno specimen changed over time since it was initially studied, in one month (7.03.2021–13.04.2021) the air layer spreading over almost the entire mesoscutum (Fig.
Photographs were taken using Leica Z16 APO stereomicroscope equipped with a Leica DFC 450 camera and processed with LAS Core and Adobe Photoshop software (brightness and contrast only).
Terminology and abbreviations follow
The following abbreviations are used in the text and plates of illustrations: ac = acropleuron; acs = acropleural sulcus; ae = arched elevation of Mt6; btc = basitarsal comb; c = cercus; cers = cercal setae; cly = clypeus; cs = covering setae of the linea calva; cuf = cubital fold; F1, F2, etc. = funicular segments 1, 2, etc.; hyp = hypopygium; lc = linea calva; LOL = minimum distance between the anterior ocellus and a posterior ocellus; ls = line of setae along marginal vein of hind wing; mps = multiporous plate sensilla; Mt1, Mt2, etc. = metasomal terga, numbering starts from petiole (Mt1); OOL = minimum distance between an eye margin and the adjacent posterior ocellus; OCL = minimum distance between a posterior ocellus and the occipital margin; opo = outer plates of ovipositor; pl3 = metapleuron; POL = minimum distance between the posterior ocelli; pre = prepectus; r = radicle; sp = spiracle; spf = spur fold;spv = spur vein; st = strigil; syn = syntergum; v1+v2 = ovipositor stylet; v3 = ovipositor sheath.
SIZK = I. I. Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine (Kyiv);
Chalcidoidea Latreille, 1817
Sulia glaesaria Simutnik, 2015 (
Holotype
,
New material
: SIZK, no. L-139, 1♀, vicinities of Voronki village, Vladimirets District, Rovno Region, Ukraine; Rovno amber; late Eocene. The inclusion is in a yellow and clear piece of amber in a shape of triangular prism (ca. 20 × 16 × 15 × 7 mm) (Fig.
Body robust, barrel-shaped; clypeus setose, with long lateral margins and sharp ventrolateral angles; scape with apicoventral depression; funicle cylindrical; dorsoapical part of mesopleuron with convex differentiated region ventral to tegula delineated by sulcus; linea calva without filum spinosum, but with well-developed line of long setae along basal margin of dorsal surface; costal cell of hind wing with single line of long setae along the entire marginal vein; spur vein or fold originating from the marginal venation of the hind wing present but visible only at some angles; strigil and basitarsal comb present; gaster barrel-shaped, syntergum rather vertical with abruptly reflexed extension apically; cerci only slightly advanced toward gastral base; apex of hypopygium far from reaching apex of gaster; outer plates of ovipositor narrow, crescent-shaped in lateral view.
Female. Largest known fossil encyrtid, body length 1.7–1.9 mm, not flattened, robust, barrel-shaped.
Coloration. Head and body black, but appear silvery where surrounded by thin layer of air (only in these places a shallow reticular sculpture visible, Figs
S. glaesaria, female, holotype A habitus, left lateral B habitus, ventral C head, frontal D forewing venation (cly – clypeus, hyp – hypopygium, ls – line of setae, opo – outer plates of ovipositor, pl3 – metapleuron, r – radicle, sp – spiracle) number of mandibular teeth not visible; maxillary palpi 4-segmented; labial palpi 3-segmented (Fig.
Head. Lenticular, as wide as thorax, broader then long, frontovertex curved to posterior ocelli; broadly rounded in frontal view, not vaulted above eyes; eyes bare, without visible microtrichia, inner orbits parallel over much of height but ventrally divergent (Figs
Antenna. Geniculate, 11-segmented, without differentiated anelli, with 6 funicular segments and with 3-segmented clava; radicle short, about 2–2.5× as long as broad (Fig.
Mesosoma. Pronotum almost vertical, but in dorsal view with very narrow transverse dorsal surface (Figs
Wings. Fully developed. Fore wing with basal cell uniformly setose; costal cell broad; submarginal vein with single line of long setae, parastigma with two lines of shorter setae; cubital vein present as non-pigmented but distinct fold (Fig.
S. glaesaria, females, wings A–E Rovno specimen F holotype from Danish amber A left pair of wings dorsal B forewing venation, dorsal C left pair of wings, ventral D right pair of wings, venation, dorsal E left pair of wings, hind wing venation, ventral F wings venation, ventral. (cs – covering setae, cuf – cubital fold, lc – linea calva, ls – line of setae, spv – spur vein). Scale bars: 0.2 mm.
Legs. Relatively short, stout; all coxae large, with polygonal reticulate sculpture (only visible under layer of air, Figs
Gaster. Sculpture of gaster not visible, apical margins of Mt2 –Mt5 straight, parallel; Mt6 with a small arched elevation medially (Figs
Male. Unknown.
Type species only.
Unknown.
The radicle of many recent encyrtids is very long, four times or more as long as broad. This character state is included in lists of synapomorphies of extant Encyrtidae by
The forewing venation of S. glaesaria is typical for fossil Encyrtidae. In modern encyrtids, the most similar venation of the forewings occurs, e.g., in the genera Savzdargia Trjapitzin, 1979, Ericydnus Walker, 1837, Mira Schellenberg, 1803, and Moraviella Hoffer, 1954 (Tetracneminae). All veins are long, including the marginal. The linea calva has a line of long setae along its basal margin (Fig.
In the hind wing of S. glaesaria, the costal cell has a membrane with a single line of long setae along the entire marginal vein as in Tanaostigmatidae. A similar character state is rarely present in extant Encyrtidae, e.g., in Exoristobia Ashmead, 1904. The fossil E. sugonjaevi also has this line of setae, but it differs from S. glaesaria by the hypopygium extending past the apex of horizontal syntergum.
A spur vein or fold originating from the marginal venation of the hind wing is visible in S. glaesaria (Fig.
The both specimens of S. glaesaria have almost vertical syntergum (Figs
The taxonomic position of the Sulia is retain unplaced within the Encyrtidae. Its biology is also unknown. Nevertheless, a large size of S. glaesaria, its barrel-shaped habitus, short and high acropleuron, structure of protibial apex, presence of spur vein and line of long setae along the entire marginal vein of hind wings, and supposedly almost vertical syntergum somewhat resemble those of members of Tanaostigmatidae and may indicate convergent adaptation to the plant galling.
We are grateful to Gary A.P. Gibson (Canadian National Collection of Insects and Arachnids) and James Woolley (Texas A&M University) for discussion and valued comments; Lars Vilhelmsen (Zoological Museum of University of Copenhagen) kindly arranged a loan of specimens; Bruce Archibald (Simon Fraser University, Burnaby, Canada) for valued comments and editing the English. The authors are thankful to the editor Petr Janšta.
This work was supported by grant NRFU No. 2020/02/0369 (to S.A. Simutnik).