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The dominance of ants in the terrestrial biosphere has few equals among animals today, but this was not always the case. The oldest ants appear in the fossil record 100 million years ago, but given the scarcity of their fossils, it is presumed they were relatively minor components of Mesozoic insect life. The ant fossil record consists of two primary types of fossils, each with inherent biases: as imprints in rock and as inclusions in fossilized resins (amber). New imaging technology allows ancient ant fossils to be examined in ways never before possible. This is particularly helpful because it can be difficult to distinguish true ants from non-ants in Mesozoic fossils. Fossil discoveries continue to inform our understanding of ancient ant morphological diversity, as well as provide insights into their paleobiology.

In the course of ongoing revision of the ant genus Myrmica Latreille, 1804, we located, in the collections of the Russian and Polish Academies of Sciences, pieces of Baltic Amber (Late Eocene, ca. 40 Ma; earlier this amber was considered to be Oligocene, e.g., see Wheeler, 1915; Larsson, 1978; Bolton, 1995; Dlussky, 1997), that each contained a fossilized specimen of Myrmica. We were also fortunate to be given access to a piece of Saxonian Amber (the same age as Baltic Amber) from the collection of Manfred Kutscher that contained three specimens of Myrmica. Four of the specimens belong to two new species. We describe these below, placing them in context with extant species, and we re-appraise all previously described fossil Myrmica, providing a key to the identification of the five extinct “true” Myrmica species.

The types and undescribed material of the hymenopteran fossils of the Insect Bed of the Bembridge Marls from the Isle of Wight (UK) are critically revised and studied. A total of 1460 fossils are recorded and attributed to 20 families: Gasteruptiidae s.l. (1); Proctotrupidae (3); Diapriidae (24); Cynipidae (7); Figitidae (6); Pteromalidae (1); Agaonidae (3); Scelionidae (12); Platygastridae (2); Ichneumonidae (32); Braconidae (75); Bethylidae (3); Crabronidae (2); Sphecidae (1); Apidae (2); Scoliidae (1); Tiphiidae (2); Vespidae (4); and Formicidae (1220). Described as new are 51 species, 13 genera, two tribes and two subfamilies. Minimum number of species recorded (either as described species or representing higher taxa with no described species in the assemblage) is 118. The composition of the hymenopteran assemblage is most similar to that of Baltic amber and indicative of a well forested territory, as well as of a humid, equable (aseasonal but not very hot) climate, more typically equable than in the Baltic amber source area, judging from the absence of Aphidiinae and scarcity of aphids.

Two new species of weaver ant are described from the Eocene of Germany. Males and gynes of Oecophylla longiceps

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The Ants of the GenusLasius(Hymenoptera, Formicidae) from Late Eocene European AmbersFinds of the genusLasiusFabricius in the Baltic, Bitterfeldian, Rovno, and Scandinavian Ambers (Late Eocene) are revised. Neotypes ofL. pumilusMayr, 1868 andL. punctulatusMayr, 1868 are designated. A key to workers and gynes ofLasiusspecies from the Late Eocene European ambers is compiled. AllLasiusspecies from these ambers belong to the subgenusLasiuss. str.L. schiefferdeckeriMayr, 1868 is one of most abundant ant species in the Late Eocene European ambers: it consists 15.2-19.5% of all ant specimens in Baltic Amber, 24.5% in Bitterfeldian Amber, 23.8% in Rovno Amber, and 23.6% in Scandinavian Amber of the examined collections. Based on the features of fossilization of this species, it is possible to assume that at least in part it constructed arboreal nests and made roads to aphids' colonies. The list of nine ant species found in syninclusions withL. schiefferdeckeriis provided.

Abstract:The ant assemblage of Radoboj (Croatia) described by Heer (1849, 1867) is considered the richest known Miocene assemblage of Europe. However, Heer's data can no longer be used for analysis of the palaeontological history of ants, because they are strongly outdated and require a revision. Such a revision was the purpose of our study. We found in collections of three museums of Austria (Universalmuseum Joanneum in Graz, Geologische Bundesanstalt, and Naturhistoricshes Museum in Wien) a total of 537 compression fossils of ants from Radoboj, 459 of which were identified earlier by Heer. We designated the holotypes, lectotypes and neotypes for 54 of the 62 species described by Heer, and subsequently compared the other specimens to these types. As a result, we have identified 350 specimens to subfamily and 309 specimens to species. We re-described 23 species originally described by Heer (1849, 1867) and two species described by Mayr (1867). One genus and eight species are described as new; 27 species and varieties described by Heer are synonymized. The taxonomic placement of eight species described by Heer remains unclear. As a result of our revision, the known assemblage of Radoboj includes 33 species of 15 genera and five subfamilies. The assemblage of Radoboj is especially similar at the subfamily level to the assemblage of Bembridge, UK (Late Eocene) and Stavropol, RF (Middle Miocene).