A peculiar new genus of Scytinopteridae (Hemiptera, Cicadomorpha) from the Permian- Triassic boundary beds of Mongolia

Abstract

Beloscyta edi gen. et sp. nov., named in honour of Ed Jarzembowski, is described from the uppermost Permian (or lowermost Triassic?) of Yaman-Us, South Mongolia. Pointed coleopterous tegmina lacking the costal fracture and the claval furrow indicate that the flying ability in the new scytinopterid was reduced or lost, and the peculiar shape of the tegmina probably helped to mimic host plant buds or seeds. The plant and insect assemblages of the sandstone member of the Yaman-Us Formation are similar to those known from the Permian-Triassic intertrappean beds of the Tunguska and Kuznetsk basins.

Full text

Palaeoentomology 5(3): 218–221 (published 23 June 2022)
https://doi.org/10.11646/palaeoentomology.5.3.2
http://zoobank.org/urn:lsid:zoobank.org:pub:30DDF346-A6E6-4EAB-BAF2-08F14811CDA5
A peculiar new genus of Scytinopteridae (Hemiptera, Cicadomorpha) from the Permian-
Triassic boundary beds of Mongolia
DMITRY E. SHCHERBAKOV
Borissiak Paleontological Institute, Russian Academy of Sciences, Moscow, Russia.
dshh@narod.ru; https://orcid.org/0000-0003-4508-9259
Scytinopteridae Handlirsch, 1906 is a widespread family of extinct Cicadomorpha known
worldwide from the Permian and Triassic (Lambkin, 2016). This family was understood very
broadly (e.g., Evans, 1956), but was later restricted to the genera with heavily sclerotized
punctate tegmina having a costal fracture and a hypocostal socket fixed on the thorax in repose,
and was placed in the superfamily Scytinopteroidea Handlirsch, 1906 (Shcherbakov, 1984).
Based on these features, scytinopteroids are considered inhabitants of waterside vegetation
capable of temporary submergence, and are ancestors of true bugs (Shcherbakov, 1996, 2000). In
the beds near the Permian-Triassic boundary of Mongolia, an unusual new genus of
Scytinopteridae was discovered with pointed coleopterous tegmina lacking the costal fracture
and the claval furrow. These modifications indicate that the flying ability in the new
scytinopterid was reduced or lost, and the peculiar shape of the tegmina probably helped to
mimic host plant buds or seeds (plant-part mimicry).
The site near the Yaman-Us spring is located 110 km SE Dalanzadgad, South Mongolia. The
Yaman-Us Formation exposed there, is subdivided into the lower coal-bearing member with
cordaite flora and the upper sandstone (coal-free) member and is overlain by the Triassic.
According to the plant assemblages, this formation is considered to be completely Upper
Permian (Gomankov, 2020; Uranbileg 2020), except perhaps the upper part of the sandstone
member (Durante & Uranbileg, 2002: fig. 5), in which an insect assemblage of Triassic
appearance was found (Shcherbakov, 2008). Cordaites are absent in the sandstone member, and
the plant megafossils of its basal layer 24 are represented only by Peltaspermaceae seed ferns
(Uranbileg, 2020). Insects, conchostracans, mosses and fragments of vascular plants were
collected from a mudstone lens in the next layer 25. Four acrocarpous moss species in four
genera were described from there (Ignatov & Shcherbakov, 2011). One of these genera,

Palaeosyrrhopodon, was later reinterpreted as a peculiar small aquatic lycopsid of the order
Isoetales (and possible liverworts mentioned by Uranbileg 2020, as its roots); this genus and
fern-like pinnules found in layer 25 are similar to the taxa known from the Permian-Triassic
intertrappean beds of the Tunguska and Kuznetsk basins (Gomankov, 2020). In abundance of
protorthopterous Chaulioditidae (Aristov, 2005) and mayfly nymphs, the insect assemblage of
layer 25 is similar to those known from the Permian-Triassic intertrappean beds of the Tunguska
and Kuznetsk basins (Aristov, 2011; Sinitshenkova 2013, 2021). Siberian Traps overlying coal-
bearing sequences with cordaite flora are traditionally considered Lower Triassic, including in
regional stratigraphic schemes, but the lower intertrappean beds containing these entomofaunas
correspond to the uppermost Permian of the Global Stratigraphic Scale (see Shcherbakov et al.,
2021).
The material is deposited at Borissiak Paleontological Institute, Russian Academy of
Sciences, Moscow (PIN). Photographs were taken using a Leica M165C stereomicroscope with a
Leica DFC425 digital camera. Scanning electron images of uncoated specimens were obtained
with TESCAN VEGA3 microscope using backscattered electron detector (BSE). The vein
nomenclature follows Shcherbakov (1984, 1996).
Systematic palaeontology
Order Hemiptera Linnaeus, 1758
Infraorder Cicadomorpha Evans, 1946
Superfamily Scytinopteroidea Handlirsch, 1906
Family Scytinopteridae Handlirsch, 1906
Beloscyta gen. nov.
lsid:zoobank.org:act:F0A3AD98-5143-44CF-A46F-E3468BE591C6
Type species. Beloscyta edi sp. nov.; by present designation.
Included species. Type species.
Etymology. From Greek belos (arrow, dart, sting) and skytos (hide, skin, leather); gender
feminine.
Diagnosis. Tegmen strongly convex, deeply punctate, narrowed to acute apex. Claval
furrow and costal fracture obliterated. Basal cell open, R+M and CuA stems not connected at
base. R apparently simple, apical branches of M and CuA in posterior pecten. Pronotum
trapezoidal, lateral margins foliaceous.

Remarks. Distinct from all other Scytinopteridae and Scytinopteroidea in the pointed
coleopterous tegmen without costal fracture and claval furrow. In the tegmen strongly tapered
towards narrow apex, similar to Ipsviciidae Tillyard, 1919 (Triassic–Early Jurassic), but in the
latter the tegmina are less convex and sclerotized, with finer sculpture, and retain the claval
furrow, costal fracture, closed basal cell, and distinct anterior R branches.
Beloscyta edi sp. nov.
lsid:zoobank.org:act:A4DAA37E-3271-47F2-B7E2-8FA036B2B71E
(Fig. 1)
Material. Holotype left tegmen PIN 5006/17±, paratype fragment of thorax with basal parts
of tegmina PIN 5006/18; Yaman-Us (= Yamaan Us) 26 km ENE of Nomgon, 110 km SE of
Dalanzadgad, Ömnögovi Province, Mongolian Republic.
Etymology. In honour of our friend and colleague Ed Jarzembowski, for his passion for
fossil insects.
Locality and horizon. Yaman-Us Formation, upper (sandstone) member, uppermost
Permian (or lowermost Triassic?).
Description. Tegmen 6.8 mm long, elongate (2.9:1), widest at 1/4 its length, then gradually
narrowed to acute apex. Costal margin convex, deeply arched near base; precostal carina wide
proximally, deflected dorsad; hypocostal carina narrow; basicostal projection (associated with
hypocostal socket fixed on mesepimeral knob in repose) large, reaching low arched, obscure
base of Sc; costal fracture absent; costal area wide near base, gradually tapered distally. Basal
cell open (no arculus or junction of R+M with CuA); R+M and CuA parallel near base and
diverge more distally; M diverging from R slightly distad of R+M – CuA divergence. R arched
anteriad, simple, joining anterior margin slightly before tegmen apex, without discernible
anterior branches, with slight bends probably marking their origins. M and CuA stems nearly
straight. Two crossveins, r-m and m-cu, beyond 1/4 tegmen length, r-m more distal. Apical
branches of CuA and M forming common posterior pecten with 8 terminations, anterior apical
cells narrow, posterior apical cells wide, weak posteriormost CuA branch joining CuP. CuP
weak, slightly convex; claval furrow absent. Clavus occupying 2/3 tegmen length, claval veins
(Pcu and 1A) united at 4/5 clavus length, their common stalk after junction with CuP continued
as ambient vein running close to margin up to near tegmen apex. Vein along commissural
margin in form of flat strip densely beset with microtrichia (stripes of left and right tegmina
could overlap in repose). Tegmen markedly convex, especially about midlength, except for
depressed area of basal cell; main veins subcarinate, surface covered with strong rasp-like

punctures (bases of setae, deepest near clavus base) and microscopic granules (microtrichia);
bases of large setae along CuA and Pcu; marginal row of minute pits around tegmen apex.
Tegmen dark, costal and scutellar edges margined with pale. Pronotum trapezoidal, much wider
than long, surface finely tuberculate-rugulose, angles rounded, posterior margin straight, lateral
margin 1.9 mm long formed by moderately wide paranotal carina, nearly straight, at about 60° to
posterior margin.
Acknowledgements
I am very grateful to Roman Rakitov (PIN) for his help with SEM imaging. The study was
supported by the Russian Science Foundation (project 21-14-00284).
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FIGURE 1. Beloscyta edi gen. et sp. nov., A–F, Holotype tegmen, A–D, SEM (BSE), E,
Photograph, A, D, E, Part (images flipped), B, C, Counterpart. A, E, Whole tegmen. B, Base. C,
Surface sculpture. D, Apex. F, Venation. G, Paratype (photograph). Scale bars = 1 mm (A, E–
G), 0.4 mm (B), 0.2 mm (C, D).