Gennady M. Dlussky

New middle Eocene formicid species from Germany and the evolution of weaver ants

Two new species of weaver ant are described from the Eocene of Germany. Males and gynes of Oecophylla longiceps Dlussky sp. nov. are found in the middle Eocene (about 47 Ma) of Grube Messel, Germany. Males, gynes and two workers of O. eckfeldiana Dlussky sp. nov. are recorded from the middle Eocene (about 43 Ma) of Eckfeld maar, Germany. The two new species are among the oldest records of the extant genus Oecophylla. First adaptations for moving in the forest canopy are present in the workers of O. eckfeldiana. Even more specialized adaptations for arboreal life are found in the workers of O. brischkei from Baltic amber. The coexistence of two species in Baltic amber and in the Bembridge marls suggests that in these cases different ecological niches were realised by sympatric species. Comparisons of the queens from different fossil and extant species indicate morphological trends, partly connected with increasing fertility. Most likely Oecophylla originated in the early Paleogene in the Palaearctic realm, radiating strongly during the climatic changes of the Eocene—Oligocene transition.

The wasps, bees and ants (Insecta: Vespida=Hymenoptera) from the Insect Limestone (Late Eocene) of the Isle of Wight, UK

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.

THE ANTS OF THE GENUS MYRMICA (HYMENOPTERA, FORMICIDAE) FROM BALTIC AND SAXONIAN AMBER (LATE EOCENE)

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. Until now, seventeen extinct ant species have been ascribed to the genus Myrmica (Heer, 1850, 1867; Mayr, 1868b; Novak, 1878; Meunier, 1915): four species from the Late Eocene and Oligocene (ca. 40–35 Ma) and thirteen from the Miocene (ca. 25 Ma). However, only one of these species, M. longispinosa Mayr, 1868b found in Baltic Amber, indisputably belongs to the genus. All other fossil “ Myrmica ” species belong to other genera. The high number of misidentifications is not surprising because most species were described a long time ago from impressions in rock. Such fossils are very difficult to interpret and identify correctly, even with considerable experience and a good knowledge of recent ant taxonomy. Three species, M. pusilla Heer, 1850, M. duisburgi Mayr, 1868b, and M. rugiceps Heer, 1850 were formally transferred to other genera by Handlirsch (1907), Wheeler (1915) and Assmann (1970) respectively (see also Mayr, 1867; Bolton, 1995), and …

Two new primitive ant genera from the late Eocene European ambers

Two extinct genera of ants from the late Eocene (ca. 40 Ma), Protomyrmica gen. nov. and Plesiomyrmex gen. nov. (family Formicidae, subfamily Myrmicinae), are described based on single specimens (males), from Baltic and Bitterfeld (also called Saxonian) ambers respectively; both genera belong to the tribe Myrmicini. In gross morphology they are similar to modern Myrmica but have a series of apomorphies combined with characters that are plesiomorphic not only in the tribe Myrmicini, but also in the subfamily Myrmicinae. The most significant plesiomorphies concern the antennal structure and wing venation of both genera. The antennal scape is short and the funiculus is filiform, having no apical club. Moreover, the antennae of Protomyrmica are “sphecoid” with the length of the funicular segments gradually decreasing towards the apex (i.e., the longest is basal, starting from the second, and the shortest is apical); this type of structure is basal for the family Formicidae as a whole. Although we consider the wing venation of Protomyrmica to represent the prototype of wings in the subfamily Myrmicinae, it has an apomorphy absent in the modern Myrmicini genera—the antennae are inserted into the head well behind the posterior margin of the clypeus. Plesiomyrmex also has a peculiar apomorphy not found in any other genus of Myrmicinae: the antennae are inserted into toruli located on short sub-vertical tube-like or cup-like structures that protrude distinctly above the head surface. As a result, we do not consider either of the newly described genera to be the direct ancestors of modern Myrmicini; nevertheless, the presence of very ancient plesiomorphies may indicate their antiquity, and thus the latest estimated time for the origin of the tribe Myrmicini should be at least the early Eocene.

Early Miocene Formicidae (Amblyoponinae, Ectatomminae, ?Dolichoderinae, Formicinae, and Ponerinae) from the Foulden Maar Fossil Lagerstätte, New Zealand, and their biogeographic relevance

Abstract. The fossil record of Australasian Formicidae is extremely sparse. It currently comprises two ants in the subfamilies Ponerinae and Dolichoderinae from Plio/Pleistocene strata in Victoria, Australia, 14 as-yet undescribed ants from Cape York amber, and one ant in the subfamily Amblyoponinae from the early Miocene Foulden Maar in southern New Zealand. Here, we report on a diverse myrmecofauna preserved as compression fossils from Foulden Maar and describe Amblyoponinae gen. et sp. indet., Rhytidoponera waipiata n. sp., Rhytidoponera gibsoni n. sp., Myrmecorhynchus novaeseelandiae n. sp., and Austroponera schneideri n. sp. Further isolated wings are designated as Formicidae sp. A, B, and C, the former resembling a member of subfamily Dolichoderinae. Fossils of Austroponera and Myrmecorhynchus are reported for the first time, whereas Rhytidoponera waipiata n. sp. and R. gibsoni n. sp. are the first Southern Hemisphere fossil records of this genus. The fossil taxa from Foulden Maar establish the subfamilies Ectatomminae, Formicinae, Ponerinae and, possibly, Dolichoderinae in the Australasian region in the early Miocene and provide evidence that the few native ants in the extant New Zealand fauna are the surviving remnant of taxonomically different, possibly more diverse, warm-temperate to subtropical myrmecofauna.

A new trap-jaw ant species of the genus Odontomachus (Hymenoptera: Formicidae: Ponerinae) from the Early Miocene (Burdigalian) of the Czech Republic

Odontomachus paleomyagra sp. nov. is described from the Early Miocene of the Most Basin (Czech Republic) on the basis of a single-winged female, representing one of the rare reports of fossil Odontomachini. The new species is separated easily from other trap-jaw ant species groups by differences in mandibular morphology (without denticles on the inner side) and distributional occurrence. The evolutionary and biogeographic history of the Odontomachini is briefly discussed.KurzfassungAus dem Unter-Miozän im Most Becken (Nord Böhmen; Tschechische Republik) wird erstmals ein Exemplar der Ameisen-Gattung Odontomachus beschrieben und abgebildet. Die neue Art, Odontomachus paleomyagra sp. nov., unterscheidet sich von anderen Angehörigen der Schnappkieferameisen, vor allem durch Unterschiede in der Morphologie der Mandibeln (ohne Zähnchen an der Innenseite) und ihrer ungewöhnliche biogeographischen Verbreitung. Die evolutionäre und biogeographische Geschichte der Odontomachini wird kurz diskutiert.

A New Enigmatic Ant Genus from Late Eocene Danish Amber and Its Evolutionary and Zoogeographic Significance

Usomyrma mirabilis gen. et sp. nov., belonging to the tribe Leptomyrmecini of the subfamily Dolichoderinae, are described based on two males from the late Eocene Danish Amber. Usomyrma differs from Leptomyrmex by a set of plesiomorphic and autapomorphic features. Distinctly plesiomorphic characters include the fore wing venation, i.e., the presence of the well developed pterostigma, the wide closed cell 3r and the big central closed cell that formed by the fusion of the cells (1+2r)+mcu, and the structure of mandibles, which are elongate-triangular, with a well developed masticatory margin that, unlike Leptomyrmex, possesses a set of well developed, relatively long and sharp teeth. The most distinctive autapomorphy of Usomyrma is the structure of the antennae: although it remains 13-segmented, its second funicular segment is extremely elongate, much longer than any other segment, including the apical one. The generic composition of the tribe Leptomyrmecini is partly reassessed compared to the previously published data. We propose to establish a new informal Leptomyrmex genus-group within tribe Leptomyrmecini, including in it the extant genus Leptomyrmex, two fossil (Usomyrma gen. nov., Leptomyrmula) and a “Leptomyrmex” male from the Dominican Amber that probably represents a third extinct genus. Finally, a new, alternative evolutionary and zoogeographic scenario for the Leptomyrmex genus-group is proposed. We suggest that fore wing venation of Usomyrma is ancestral to other genera of this group. The next evolutionary step was the complete reduction of the closed central cell in Leptomyrmula, while conserving the pterostigma and a wide closed cell 3r. Then, in the modern Leptomyrmex males the pterostigma was reduced and the cell 3r became very narrow. Finally, the most apomorphic condition is illustrated by the venation of “Leptomyrmex” male from the Dominican Amber, which has no pterostigma and pterostigmal appendages, combined with the absence of the closed cell 3r. As a result, we suppose that the ancestor of Leptomyrmex might penetrate from Eurasia to Australia via South-East Asia, and then Leptomyrmex penetrated to South America, where the most advanced morphologically form (i.e., “Leptomyrmex” male from the Dominican Amber) arose, but extinct in Miocene.

Boltonidris Gen. Nov., the First Extinct Stenammini Ant Genus (Hymenoptera, Formicidae) from the Late Eocene Rovno Amber

Abstract. The new extinct ant genus and species, Boltonidris mirabilis, are described from the late Eocene Rovno Amber (Ukraine). This genus belongs to the tribe Stenammini of the subfamily Myrmicinae. It possesses the plesiomorphic characters of the tribe Stenammini, e.g. 12-segmented antennae with 3-segmented apical club, characteristic structure of the clypeus and frontal lobes, absence of gastral shoulder, but it has a series of autapomorphies, e.g. modified mandibles with the only two teeth on the masticatory margin, well developed longitudinal medial groove on the head dorsum, somewhat depressed areas lateral to the frontal carinae (like “vestigial” antennal scrobes), and finely swollen postero-lateral area of head, close to the occipital corners. Additionally, it has two short blunt teeth on the pronotum.

Bilobomyrma New Genus, A New Extinct Ant Genus (Hymenoptera, Formicidae) from the Late Eocene European Ambers

Abstract A new fossil ant genus, Bilobomyrma new genus, and two new species are described based on males from the late Eocene Rovno (B. ukrainica n. sp.) and Baltic (B. baltica n. sp.) ambers. We tentatively place this genus in the myrmicine tribe Formicoxenini. Bilobomyrma is characterized by its 13-segmented antennae without an apical club; by the short scape, which is subequal to the length of the first and second funicular segments together; by the shape of the second funicular segment, which is distinctly longer than the any other funicular segment except for the apical one; by the presence of notauli on the scutum; by the absence of spurs on the middle and hind tibiae. At the same time, Bilobomyrma differs from other myrmicine genera by the peculiar shape of its clypeus, having a strongly incised medially, bilobed anterior margin, and its forewing venation: the wings have three closed cells—mcu, 1+2r and 3r; the cell 3r is very short, only twice as long as its width; the distal section of veins RS and M diverge from the cell 1+2r separately.

Ants of the Genus Fallomyrma Dlussky et Radchenko (Hymenoptera, Formicidae, Myrmicinae) from Late Eocene European Ambers

The extinct monotypic ant genus Fallomyrma was described by Dlussky and Radchenko in 2006 based on workers from Late Eocene Rovno (Ukraine), Scandinavian (Denmark), and Bitterfeld (Germany) ambers. Three new Fallomyrma species from the Rovno amber are here described based on workers: F. anodonta sp. nov., F. marginata sp. nov., and F. robusta sp. nov. A key to all known species of this genus is compiled. The quantity ratios (of the numbers of species and specimens) of Fallomyrma and other amber Myrmicinae genera are considered. The opinion of the autochthonous origin of the Rovno amber is confirmed.