Magadanobracon, Belokobylskij, 2012
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https://doi.org/ 10.4202/app.2010.0120 |
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persistent identifier |
https://treatment.plazi.org/id/0391878B-0357-5E12-1F49-8877FF7FA721 |
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treatment provided by |
Felipe |
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scientific name |
Magadanobracon |
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Genus Magadanobracon nov.
Etymology: From Magadan city, central to the area where the fossil material comes from, and the braconid genus Bracon .
Type species: Magadanobracon rasnitsyni sp. nov.; see below. By present designation.
Species included.—Two extinct species M. rasnitsyni and M. zherikhini .
Diagnosis.—This genus differs from Protorhyssalus , as well as Protorhyssalodes and Aenigmabracon , by the distinctly antefurcal position of the first recurrent vein (m−cu) in the fore wing, by the brachial (CU1b) vein closing the apicoposterior part of the brachial (subdiscal) cell of fore wing, and by the short flagellar segments.
The antefurcal position of the recurrent vein (m−cu) is common for many genera of the plesiomorphic non−cyclostome subfamily Helconinae . The new genus is similar to the helconine genus Hellenius Tobias, 1982 , but distinctly differs by the presence of the second transverse anal vein (a), by the weakly antefurcal recurrent vein (m−cu), by the shortly postfurcal nervulus (cu−a), by the short first abscissa of the radial vein (r), by having the first tergite short and with complete and S−shaped dorsal keels, and by the wide hind femur.
Description.—Ocelli medium−sized ( Fig. 1C View Fig 2, B 2 View Fig ). Antenna rather thick, setiform, 28−segmented ( Fig. 2A View Fig ). Scape rather short and thick; first flagellar segment longer than second; apical segment pointed apically. Mesosoma short and wide ( Figs. 1A, B View Fig , 2B View Fig , 3A, B View Fig 1 View Fig , 4A, B). Median lobe of mesoscutum distinctly protruding, weakly convex anteriorly.Notauli deep and complete. Prepectal carina developed. Sternaulus present but shallow and narrow. Propodeum with more or less distinctly delineated areas. Fore wing ( Figs. 1C View Fig , 2C View Fig , 3B View Fig 2 View Fig , 4A). Pterostigma wide. Radial vein (r) arising shortly behind middle of pterostigma. Radial (marginal) cell not shortened. Both radiomedial veins (2−SR, r−m) present. Second radiomedial (submarginal) cell rather short and distinctly narrowed towards apex. Discoidal (discal) cell petiolate anteriorly, weakly narrowed anteriorly, with subparallel lateral margins. Recurrent vein (m−cu) antefurcal. Brachial (subdiscal) cell wide, distinctly closed posteroapically by brachial (CU1b) vein. Parallel vein (CU1a) arising almost from posterior 0.2 of distal margin of brachial (subdiscal) cell. Both transverse anal veins (a, 2A) present. In hind wing, submedial (subbasal) cell large; recurrent vein (m−cu) absent. Fore and hind femora distinctly widened, elongate−oval ( Fig. 2E View Fig ). Hind tibia of female distinctly thickened towards apex ( Fig. 2E View Fig ). Tarsal claws simple. Metasoma of female wide ( Fig. 2D View Fig ). First tergite short ( Figs. 2D View Fig , 3A View Fig 2 View Fig , B 3 View Fig , 4A, B), wide, with at least small dorsope, with distinct, more or less S−shaped and complete dorsal carinae; spiracular tubercles distinct. Second suture rather wide. Second tergite without delineated areas. Ovipositor long, about as long as costal vein ( Fig. 1A, B View Fig ).
Discussion.— Magadanobracon is putatively included in the subfamily Protorhyssalinae . The fossils available do not display all important diagnostic characters of this subfamily. Unknown character states include the presence vs. absence of the hypoclypeal depression in the mouth area, a crucial character state for assignment to the cyclostome group of subfamilies. Nevertheless the entire body of evidence looks suggestive of the cyclostome nature of the genus. Regrettably the basal posterior part of the hind wing is not preserved well enough to display the characters important for the definitive placing of the new genus to Protorhyssalinae .
Despite of limited information on the valuable diagnostic features, there is an important character of the new species, the distinctly thickened hind tibia, that represents a putative synapomorphy of the subfamily. A thick hind tibia is a characteristic of males of extant species of the cyclostome genus Rhyssalus ( Rhyssalinae ), and occurs only in some males of previously discussed Cretaceous braconids ( Protorhyssalinae and related genera). The type species of Magadanobracon represents the first female of all known Protorhyssalinae along with genera of debatable subfamily position ( Protorhyssalodes and Aenigmabracon ) ( Basibuyuk et al. 1999; Perrichot et al. 2009). It is noteworthy that this female shows thick hind tibia like supposedly related males and unlike any known females of fossil Braconidae .
The postfurcal position of the recurrent vein (meeting the second radiomedial cell distal of the first radiomedial vein) is
http://dx.doi.org/10.4202/app.2010.0120
considered to be the plesiomorphic condition for Braconidae ( Tobias 1977) , possibly except Doryctinae ( Belokobylskij 1993) . All other Protorhyssalinae and related genera ( Protorhyssalus , Protorhyssalodes , and Aenigmabracon ) have a postfurcal or sometimes ( Aenigmabracon ) subinterstitial position of this vein. Magadanobracon has the recurrent vein antefurcal, which is apparently an apomorphy of the described genus.
Stratigraphic and geographic range.— Type locality and horizon only.
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