A new species of the beetle genus Holcoptera (Coleoptera: Coptoclavidae) from the Upper Triassic of east Ukraine

. A new species, Holcoptera rasnitsyni sp.n. (Coleoptera: Coptoclavidae), is described based on four specimens from the Upper Triassic (Upper Carnian–Lower Norian) of east Ukraine. The attribution of these

The time range of Holcoptera is rather narrow. These fossil beetles have been found in sediments of all ages between the Middle Triassic (beginning from the Anisian) and the Lower Jurassic (Sinemurian). Elytra with longitudinal stripes have also been recorded from the Lower-Middle Anisian of eastern France; although very similar generally to Holcoptera, these can have twice as many stripes. These fossils have been described as a new species [Papier et al., 2005, species 10], but its holotype has never been established, so the species remains unnamed.
The geographic range of Holcoptera is also highly interesting. They are known from the eastern part of North America, England, southern Germany and northern Italy, with the easternmost occurrence in east Ukraine (described herein). There are no records from northern Germany, Eastern Europe, Siberia, Middle Asia, China, Japan, South America, Australia, or southern Africa, although numerous localities containing beetle fossils are known from these territories.
The taphonomy and paleoecology of Holcoptera are also unusual. Remains of Holcoptera are very abundant at many localities, resulting in hundreds of museum specimens being kept in England and USA. These mostly include elytra or hind wings, which generally serve for species identification, whereas some prothoracic and abdominal structures are not frequent and generally remain unidentified. Another peculiarity is enigmatic: Holcoptera hind wings, isolated and sometimes even unfolded, are very frequent in many taphocoenoses. For instance, among the abundant beetle remains collected ABSTRACT. A new species, Holcoptera rasnitsyni sp.n. (Coleoptera: Coptoclavidae), is described based on four specimens from the Upper Triassic (Upper Carnian-Lower Norian) of east Ukraine. The attribution of these fossils to Coptoclavidae is confirmed by analysis of hind wing venation. The generic name Stargelytron Ponomarenko, 2015 is synonymized under Holcoptera Handlirsch, 1907, syn.n.
Fossil beetles of the genus Holcoptera have been recorded from a variety of Mesozoic deposits. The peculiar coloration of their elytra, with alternating light and dark longitudinal stripes, makes them easy to pick out from unsorted specimens in fossil assemblages, which has resulted in hundreds of Holcoptera specimens accumulated in museum collections. Shortly before a revision of Holcoptera was published [Kelly et al., 2017], similar forms had been described from the Triassic of Germany as a separate new genus Stargelytron Ponomarenko, 2015[Ponomarenko et al., 2015, which is here regarded as a junior subjective synonym of Holcoptera Handlirsch, 1907, syn.n. in some of the localities within the Middle Keuper deposits of Lower Franconia (South Germany), there are numerous hind wings (over a hundred in total) that belonged exclusively to Holcoptera [Fedorenko, 2014;Ponomarenko et al., 2015].

Material and methods
This publication is based on a collection of beetles from the Upper Triassic (upper Carnian-lower Norian, according to Dobruskina [1982]) deposits of the Garazhovka locality in east Ukraine (Seversky Donets River basin). Insect remains at Garazhovka were first discovered in the early 1970s by geologist and paleobotanist F.A. Stanislavsky, who sent them to the Paleontological Institute in Moscow (PIN) for study and deposition. The greater part of the material was obtained during subsequent expeditions undertaken by N.S. Kalugina in 1976N.S. Kalugina in -1977. She also brought a large amount of fossiliferous rock samples from the insect-bearing bed to PIN for further investigation, but unfortunately, this has never been completed. The available collection currently includes ca. 580 inventoried insect specimens, including ca. 290 beetles, among which the four specimens belong to Holcoptera, representing a new species described below.
All specimens including types are deposited at the Borissiak Paleontological Institute, Russian Academy of Sciences, Moscow (PIN).
The fossils were photographed using a Leica M165C stereomicroscope equipped with a Leica DFC425 digital camera. The description of hind wings and concluding remarks were written by the second author. For nomenclature of wing veins and other structures, see Fedorenko [2009].
DIAGNOSIS. Body oblong and small. Head longer than pronotum. Metanotum more strongly sclerotised than other parts of body. Metaventrite transverse, metacoxa short, with small rounded femoral plates. Elytron subconvex, not wide, each with four dark longitudinal stripes. Wing short and wide, oblongum cell large and oval.
DIAGNOSIS. The new species has the palest elytra among its congeners, with the external pale field occupying about 2/ 5 of the elytron width.
DESCRIPTION. Body oval, about twice as long as wide. Elytra pale, each with four, dark, longitudinal stripes in inner three fifths; these stripes subequally distant inter se; sutural stripe curved slightly laterad along apical margin; outer three reaching neither base nor apex.
Head about as long as wide. Eyes small and round. Pronotum wider than long. Profemur 2.3 times as long as wide. Protibia slender, curved, slightly longer than femur. Metanotum heavily sclerotized, twice as wide as long. Elytra subconvex, with apices widely rounded, less so at sutural angle.
Wings, holotype PIN, No. 3320/204a (Figs. 1-2). Two almost completely folded hind wings visible, with apex of right wing somewhat unfolded; no distinct folds. Two longitudinal wing axes located in basal part of hind wing. Costal bar (cb = C+ScA+ScP+R) distinctly and densely cross-striated, consisting of strong vein C+ScA+ScP and barely detectable radial vein (R), which is narrow and desclerotized distally. Cubital bar (Cu-CuA) broken into fragments, entire in distal half only, distally extended into large, well-defined, slightly transverse oblongum cell. Cubital joint at respective pivot on CuA proximal in position, so that CuA is abruptly geniculate at considerable distance from oblongum cell in both folded wings. Median bar (M-MP) not visible except small distal section apparently retained in form of vein 'y' in left hind wing.
Clavus and jugal lobe with few veins, broken and shifted basad, two vein fragments being only detectable: (1) CuP without apical section and (2) fragment of clavus "skeleton" with remains of first and second anal cells. Distinct line 'z' on the imprint apparently represents no vein, but posterobasal wing margin or jugal fold.
Pterostigma and almost all veins are recognizable in anterior part of unfolded wing apex frontal to longitudinal axial fold. Radial cell apparently partly incorporated in complex pterostigma. Caudal and basal borders of this cell invisible, except for distal portion of radial cell limited by crossvein (r2).
REMARKS. The described hind wing is extremely similar to another unfolded wing of a coptoclavid beetle [Fedorenko, 2014]. It matches well the wing ground plan of Adephaga, notably Hydradephaga, virtually in all details. Only two features are worthy of note. Firstly, the large and elliptic oblongum cell is peculiar to nearly all Recent Hydradephaga. Secondly, the cubital joint is proximal, which has been observed in the most primitive representatives (Gyrinidae, Haliplidae) of Hydradephaga.
ETYMOLOGY. Named in honor of Alexandr Rasnitsyn.