No abstract

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