The First Eocene Species of the Genus Micrambe (Coleoptera, Clavicornia, Cryptophagidae)
Based on a fossil specimen from the Late Eocene Rovno amber (Ukraine), Micrambe sarnensis Lyubarsky et Perkovsky, sp. n., the first Eocene species of this genus is described. The new species is similar to the extant Micrambe abietis (Paykull) and M. ulicis (Stephens), differing by having the callosity with an acutangular caudolateral corner.
New Species of Stilbus (Coleoptera, Clavicornia, Phalacridae) from the Late Eocene Rovno Amber
The first Eocene species of Stilbus Seidlitz, 1872, S. bedovoyi Lyubarsky et Perkovsky, sp. n., is described from Late Eocene Rovno amber. S. bedovoyi is most similar to Stilbus atomarius (Linnaeus) and differs from it by smaller body size, strong and large punctation of elytra, and broadly oval apex of elytra.
The First Eocene Species of the Genus Cryptophagus (Coleoptera, Clavicornia, Cryptophagidae)
Based on a fossil specimen from the Late Eocene Rovno amber (Ukraine), Cryptophagus harenus Lyubarsky et Perkovsky, sp. n., an Eocene species of this genus is described. The new species is similar to the extant desert species Cryptophagus desertus Lyubarsky and C. recticollis Solsky, differing by the large callosity occupying 1/4 length of lateral margin of pronotum.
In 2015 B. Guenard with co-authors indicated that the Rovno amber ant assemblage, as described by G. Dlussky and A. Rasnitsyn (2009), showed modest support for a bias towards arboreal origin comparing the Baltic and Bitterfeld assemblages, although it is not clear whether this reflects a sampling error or a signal of real deviation. Since 2009, the Rovno ant collection has now grown more than twice in volume which makes possible to check if the above inference about the essentially arboreal character of the assemblage is real or due to a sampling error. The comparison provided suggests in favour of the latter reason for the bias revealed by B. Guenard and co-authors. The new and larger data on the Rovno assemblage show that the share of non-arboreal ants is now well comparable with those concerning the Baltic and Bitterfeld assemblages. This holds true for the both total assemblages and subassemblages of worker ants only.
Out of 49 names of genera described from Rovno amber, 10 names (20.4 %) are related to Ukrainian toponyms. One way or another, 15.7 % of names out of 217 animal species described from Rovno amber and 67 % out of 6 described plant species are related to Ukrainian toponyms and ethnonyms. Today, only 8 out of 217 species described from Rovno amber, are known from Baltic amber. Th e ratio between Ukrainian and Baltic toponyms in the names of Rovno representatives of any given family directly depends both on the degree of exploration of a family in the corresponding faunas and floras, and on the degree of a family’s link with the ecosystem of the amber forest itself. Ant Formica paleopolonica Dlussky is recorded for Rovno amber for the first time.
Based on representative collections, the ratio of tropical and Holarctic ant species in Priabonian (Late Eocene) Baltic, Bitterfeld (Saxonian), Danish and Rovno ambers is analyzed for the first time. In surveyed representative collections of Baltic amber, the ratios of Holarctic and tropical ant species are from 1.1 to 1.5; with 10 Holarctic and 9 tropical species (out of 31) in the PIN-964 collection, and 9 and 5 species (out of 29) in the Giecewicz collection; the ratio in the representative collection of Saxonian amber is 0.9, 11 Holarctic species vs. 12 tropical species (out of 55); in the representative collection of Rovno amber it is 0.65, 15 vs. 23 species (out of 79); and in the representative collection of Danish amber it is 0.64, 7 vs. 11 species (out of 36). Hence, in representative collections of Baltic amber, Holarctic species clearly prevail not just in terms of the share of their specimens (by 9.8 to 19.6 times), but also by the number of species. In Bitterfeld amber, Holarctic species are somewhat less numerous than tropical ones, but their specimens are 6 times greater. In representative collections of Rovno and Danish ambers, the number of Holarctic species is 1.5 to 1.7 times smaller than that of tropical species, but the number of their specimens is 4.9 to 6.9 times greater. The numbers of tropical and Holarctic species represented by more than one specimen is similar in Priabonian ambers, 25 versus 22, but Holarctic species include four dominants or subdominants. The abundance of temperate elements in the Priabonian amber ant fauna along with the relatively small number of tropical elements greatly distinguishes it from the Middle European Lutetian ant faunas of Messel and Eckfeld in shale, which do not have temperate elements at all. Formica phaethusa Wheeler, Glaphyromyrmex oligocenicus Wheeler, Plagiolepis squamifera Mayr, Proceratium eocenicum Dlussky, Hypoponera atavia (Mayr), Ponera lobulifera Dlussky, Aphaenogaster mersa Wheeler, and Ennaemerus reticulatus Mayr are new records for Rovno amber, and Formica gustawi Dlussky and Gnamptogenys europaea (Mayr) for Danish amber.
The inventory of the trichopterofaunas of all Rovno amber sites is provided for the first time. Syninclusions of all Rovno amber caddisflies determined to the species level are also listed for the first time. At least 29 named species are known in Klesov, as compared with only 21 species recorded in Bitterfeld amber. Eocene caddisflies are recorded in Belarus and Zhitomir Region for the first time, and new sites of inclusions are revealed as well: Rechitsa in Belarus, Olevsk in Zhitomir Region, Kuchotskaya Volia in Rivne Region. Rechitsa yielded Erotesis bessylenon Melnitsky et Ivanov, 2016, the first undoubtedly new Eocene taxon described from Belarus. This paper is also the first to involve the data on Danish amber caddisflies in comparison of the faunas. Only five genera from four families (Wormaldia McLachlan, 1865, Archaeotinodes Ulmer, 1912, Lype McLachlan, 1878, Holocentropus McLachlan, 1878, and Plectrocnemia Stephens, 1836) are known from four European Lagerstätten: Baltic, Bitterfeld, Danish and Rovno amber. Archaeotinodes igneusaper Melnitsky, 2009 is mentioned for Rovno amber for the first time. Genera Allotrichia McLachlan, 1880 (Hydroptilidae) and Palaeocrunoecia Ulmer, 1912 (Lepidostomatidae) are excluded from the Rovno amber fauna.
Of the three genera of Ceratopogoninae dominant in Late Eocene ambers of Europe, the two known are absent in the Early Eocene Cambay amber (India): the Holarctic genus Ceratopogon and the worldwide distributed genus Culicoides, known since the Late Cretaceous. Tropical biting midge genera (Meunierohelea and Leptoconops and genera with feminized male antennae: Camptopterohelea, Eohelea, and Gedanohelea) are abundantly represented in Cambay amber. The proportion of Ceratopogonini with feminized male antennae among all Ceratopogonidae dramatically increases from north to south: from 1.4-2.4 % in unbiased collections of Bitterfeld amber (Humboldt Museum collection) and Baltic amber (the Giecewicz collection) to 7 % in Danish amber and 12.7 % in Rovno amber; their proportion in Cambay amber is 17 %. The proportion of tropical specimens among specimens Ceratopogoninae in unbiased collections is 6.4 % in Baltic amber, 5.3 % in Bitterfeld amber, 21 % in Rovno and Danish amber, and 58 % in Cambay amber. Strong differences in the proportion of tropical components among Ceratopogoninae from different European ambers are in agreement with data on Cambay amber and so are indicative of origin of the European ambers under different climatic and hence geographic environments.
A list of all 117 hymenopteran species recorded from Rovno amber is presented for the fi rst time. Th is list includes 50 named species (43 %) known only in Rovno amber fauna. Of the remaining species, 59 (50 %) are recorded also from Baltic amber, 37 (32 %) from Bitterfeld amber, 26 (22 %) from Scandinavian amber as well. Half of the species (50 %) are known on both sides of the Subparathetys (that is, recorded in Baltic amber as well), and another half is recorded only to south of the Subparathetys (from the Rovno, Bitterfeld and Scandinavian amber only). One subfamily, Eucoilinae Th omson, one tribe, Protomicroidini Antropov, and 19 genera (Archaeocercus Simutnik, Archaeogryon Kononova & Simutnik, Astigmaton Kasparyan, Boltonidris Radchenko & Dlussky, Dipriocampe Bouček, Disogmus Főrster, Fallomyrma Dlussky & Radchenko, Foveorisus Martynova, Lissonota Khalaim, Pristomyrmex Mayr, Protomicroides Antropov, Pseudidris Kononova, Pseudotelea Kononova, Rovenosa Khalaim, Rovnoecus Antropov, Rovnoeucoila Buffi ngton & Perkovsky, Rovnosoma Simutnik, Sierola Cameron, Trjapitzion Simutnik) are recorded only from south of the Subparathetys. Th ese data provide evidence supporting the previously proposed suggestion on the diff erent origin of four main European sources of succinite. Th e data mentioned above confi rm that the source area of the Rovno amber, contrary to the Baltic amber, had been situated southwards from Subparathetys. Platystasius gracilis Kononova & Simutnik and Oxyserphus obsolescens (Brues) are recorded for the fi rst time respectively from Baltic and Scandinavian amber.