Research Article |
Corresponding author: Elijah J. Talamas ( billy.jenkins@GMAIL.COM ) Academic editor: Zachary Lahey
© 2021 Jonathan Bremer, Thomas van de Kamp, Elijah J. Talamas.
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:
Bremer J, van de Kamp T, Talamas EJ (2021) Janzenella theia Bremer & Talamas (Platygastroidea, Janzenellidae): a new species from Baltic amber. In: Lahey Z, Talamas E (Eds) Advances in the Systematics of Platygastroidea III. Journal of Hymenoptera Research 87: 223-233. https://doi.org/10.3897/jhr.87.67256
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A new species, Janzenella theia Bremer & Talamas, sp. nov., is described from Baltic amber, which is the second known species of the family Janzenellidae (Platygastroidea). Synchrotron scanning was performed to observe internal structures and external morphology that was occluded by turbidity in the amber matrix surrounding the specimen.
Eocene, paleontology, synchrotron
Platygastroid wasps are well represented in amber deposits, offering opportunities to study the evolution of numerous lineages within the superfamily. Based on published records and our direct examination of specimens, the platygastroid fauna in Eocene amber is a combination of extant and extinct genera (
We here describe a new species from Baltic amber in the extant genus Janzenella Masner & Johnson. Janzenella has a distinct metasoma in which the anterior margins of the first tergite and sternite are non-carinate, a form found only in Janzenella and the scelionid genus Mantibaria Kirby (
Photographs were taken with a Leica DMRB compound microscope with a GT-Vision Lw11057C-SCI digital camera attached and rendered using the program CombineZP, or with a Macropod Microkit with images rendered using Helicon Focus. Some specimens for electron microscopy were coated in ~70 nm of gold/palladium using a Cressington sputter coater and imaged with a Hitachi TM3000 Tabletop Microscope at 15 keV. Uncoated specimens were imaged using a Phenom XL G2 Desktop SEM at 5 keV. In some cases, multiple images were stitched in Adobe Photoshop to provide larger images with high resolution and magnification.
Synchrotron microtomography was performed at the imaging cluster of the KIT light source of Karlsruhe Institute of Technology using a parallel polychromatic X-ray beam produced by a 1.5 T bending magnet. Scans were done by taking 3,000 projections at 70 frames per second and an optical magnification of 10×, resulting in an effective pixel size of 1.22 µm. The beam was spectrally filtered by 0.2 mm aluminum with a spectrum peak at about 15 keV and a full-width at half maximum bandwidth of about 10 keV. A fast indirect detector system was employed, consisting of a 10 µm (10×) LuAG:Ce scintillator, diffraction limited optical microscope (Optique Peter) and a 12bit pco.dimax high speed camera with 2016 × 2016 pixels. We used the control system concert (
The raw scan images are available individually at https://doi.org/10.5281/zenodo.4608043, and as a multipage tiff at https://doi.org/10.5281/zenodo.4608412. All rendered images, including those not included as figures are available at https://doi.org/10.5281/zenodo.4608788.
amem anterior extension of the mesofurca (Figure
fu1a profurcal arms (Figure
fu2 mesofurca (Figure
fu3 metafurca (Figure
lmfa lateral mesofurcal arms (Figure
lo lateral ocellus (highlighted in red) (Figure
mo median ocellus (Figure
mnt metanotum (Figures
ts tibial spur (Figures
Janzenella Masner & Johnson, 2007: 2 (original description. Type: Janzenella innupta Masner & Johnson, by monotypy and original designation).
Our generic description comprises the characters shared by J. innupa and J. theia, and thus is largely a reduction of the description of J. innupta provided by Masner & Johnson (2007). Two characters, the tibial spur formula and the morphology of internal apodemes, were not assessed for both species but are assumed to be stable within the genus. Nomenclature of internal structures follows
Small, elongate, length 1.2–1.3 mm; body strongly depressed, with relatively short legs and antennae; macropterous.
Head. Head transverse in dorsal view, width 1.5 times length, somewhat narrowed medially; hyperoccipital carina absent, head in frontal view wider than high, height 0.8 times width; frons largely flat to weakly convex, smooth; interantennal process absent, torulus large, opening forward, lower rim of torulus nearly reaching oral cavity; submedian carina absent; orbital carina absent, lower frons reflexed ventrally; inner orbits rounded, diverging dorsally and ventrally; clypeus very small, triangular, not differentiated into postclypeus, anteclypeus; malar sulcus absent; malar and facial striae absent; labrum not visible externally; mandible short, robust, tridentate, teeth subequal in size; antenna 11-merous; radicle inserted apically into A1, nearly parallel to axis of A1; A1 short, strongly widened in apical half, apex excavate for reception of flagellum; A3 distinctly shorter than A2; A3–A5 globular; apical 4 antennomeres expanded into semi-abrupt clava in female; papillary sensilla on female antenna arranged in longitudinal pairs on apical antennomeres; claval formula A8–A11: 2-2-2-1.
Mesosoma. Mesosoma strongly depressed, in dorsal view longer than wide, in lateral view distinctly longer than high; pronotum in dorsal view narrowed laterally; subparallel to outline of mesoscutum, anterolateral corners rounded, anterior face extended forward into necklike elongation; transverse pronotal carina absent; vertical epomial carina absent; horizontal epomial carina present; lateral face of pronotum largely flat to weakly concave, without scrobe for reception of foreleg, anterior margin very finely foveolate; netrion absent; anterior margin of mesoscutum meeting pronotum dorsally; admedian lines absent; parapsidal lines absent, notauli absent; skaphion absent; mesoscutum with roughly circular punctate areas present on either side; transscutal articulation well developed, simple; scutellum wider than long, unarmed, nearly flat; metanotum extremely narrow, striplike, dorsellum not differentiated, keels, plicae of propodeum not developed; mesopleural carina absent; acetabular carina fine, anterior margin of ventral portion of mesepisternum straight, not projecting between fore coxae; posterior margin of mesopleuron with complete line of foveolae extending from base of forewing to mid coxa; episternal foveae absent; anteroventral portion of metapleuron rounded, not separated from lateral face by carina, metapleural pit not apparent; posterior margin of metapleuron rounded; metapleuron above hind coxa reticulate, otherwise smooth; lateral propodeum without longitudinal carinae, posterolateral corner not produced posteriorly, posterior margin broadly rounded; legs relatively short, slender, only hind femur somewhat enlarged; tarsal formula 5-5-5; forewing extending to apex of metasoma, R bifurcating apically, bulla absent; R1 absent or extremely short, therefore without postmarginal vein; r-rs (stigmal vein) present, at least longer than R1; hindwing with R very short; tibial spur formula: 1-2-2.
Metasoma. Metasoma weakly sclerotized, loosely articulated, depressed; T1–T3 subequal in length; 7 terga, 6 sterna visible externally; laterotergites extremely wide, no submarginal ridge present; laterosternites absent; no spiracles visible; anterior margin of segment 1 without anterior carina, T1 and S1 rounded and prolonged anteriorly into short neck that inserts into propodeal foramen; sutures between all segments simple, terga and sterna broadly overlapping; anterior margin of S2 straight; narrow sublateral felt fields absent.
Profurca without dorsal bridge, anterior profurcal lamellae forming long, slender processes that extend anteriorly over the basisternum; mesofurca Y-shaped, lacking an apparent dorsal bridge; metafurca slanted anteriorly, metafurcal arms simple, straight, rod-like.
Width of head decreasing anteriorly, occiput in dorsal view strongly excavated, lateral ocellus separated from inner orbit by approximately one ocellar diameter, compound eye relatively large, its length approximately 0.75 that of the head in lateral view; interorbital space broad, approximately equal to height of compound eye; mesoscutum 1.3 times wider than long; femoral depression shallow, weakly defined; forewing with R straight basally, curving toward anterior margin in distal third, R separated from costal margin by at least the width of the vein, r-rs (stigmal vein) straight, much longer than wide (>3×); 1Rs, 1Rs+1M, 2Rs, M, and Cu present as spectral veins; propodeum with coarse rugae radiating from propodeal foramen.
Janzenella theia (USNMENT01223652), head, mesosoma, metasoma, brightfield photography 1 dorsolateral view 2 ventrolateral view.
Holotype female, USNMENT01223652 (Hoffeins #0002-7), Kaliningrad, Russia, coll. Yantarny, 2015 (deposited in Senckenberg Deutsches Entomologisches Institut, Müncheberg, Germany).
Janzenella theia differs from J. innupta in just a few notable characters. The compound eyes of J. theia are significantly larger than those of J. innupta, occupying most of the lateral head (compare Figures
Janzenella theia (USNMENT01223652), head, mesosoma, metasoma 3 lateral view 4 anterolateral view.
5 Janzenella innupta (OSUC 264384), head, anterior view 6 J. theia (USNMENT01223652), head, anterior view 7 J. innupta (OSUC 264384), head, dorsal view 8 J. theia (USNMENT01223652), head, dorsal view.
9 Janzenella innupta (OSUC 264400), fore and hind wings, dorsal view 10 J. theia (USNMENT01223652), fore and hind wings, ventral view 11 J. innupta (OSUC 264384), mesosoma, dorsolateral view 12 J. theia (USNMENT01223652), mesosoma, posterodorsal view.
The species is named after Theia, the mythical Greek titaness of sight, who is credited with endowing precious stones with their brilliance and intrinsic value. The name is treated as an appositional noun.
Janzenella theia and J. innupta are remarkably similar (compare Figures
13 Janzenella theia (USNMENT01223652), profurca, posterior view 14 J. theia (USNMENT01223652), mesofurca, posterior view 15 J. theia, metafurca, posterior view 16 J. innupta (OSUC 264397), mesotibia, lateral view 17 J. innupta (OSUC 264397), metatibia, lateral view.
Metanotum. The lateral metanotum in J. innupta (Figure
Profurca.
Mesofurca.
Janzenella innupta (OSUC 264384), head, mesosoma, metasoma, lateral view.
The phylogenetic treatment of
We thank Christel Hoffeins, whose loan of Baltic amber made this study possible, and Dr. Lubomír Masner, Canadian National Collection of Insects, who kindly provided specimens of J. innupta for comparative analysis. Jonathan Bremer and Elijah Talamas were supported by the Florida Department of Agriculture and Consumer Services- Division of Plant Industry.