Again on the dinosaur ants, fossil and extant

By Cesare Baroni Urbani
Institut für Natur-, Landschafts- und Umweltschutz (NLU)
Biogeographie
Neuhausstrasse 31
CH-4057 Basel Switzerland
Phone + 41 61 639 23 06
Uni Zentrale + 41 61 267 31 11
Fax + 41 61 639 23 07

E-mail: Cesare.Baroni-Urbani@unibas.ch

     The most famous ant finding of the 20th century "Nothomyrmecia macrops Clark" was shown recently to belong to a genus described over 100 years ago from Baltic amber: Prionomyrmex (Mayr, 1868; Baroni Urbani, 2000). The correct name for the Australian species often referred to as "the dinosaur ant" for its possession of several plesiomorphic traits is hence Prionomyrmex macrops (Clark). The genus Prionomyrmex is the sole known representative of an ant subfamily, the Prionomyrmecinae (= Nothomyrmeciinae), sister group of the Recent Australian Myrmeciinae. The paper by Baroni Urbani (2000), however, left some uncertainties about the status of the type species of the genus, P. longiceps Mayr. The two specimens on which he re-described the genus were considered as representing a new species (janzeni) (Fig. 1) differing from primaevus for having hairless scapes. The original material on which longiceps was described by Mayr (1868) and by Wheeler (1915), however, is no longer available in what remains of the original amber collection from Königsberg. A catalogue of the Königsberg collection now preserved in Göttingen is available in electronic form from Dr. Hans Jahnke, Göttinger Zentrum für Geowissenschaften, Göttingen, Germany.
     The presence of hairs on the scapes of P. longiceps was drawn from fragments of sentences in the descriptions by Mayr (1868) and Wheeler (1915). Recently another Prionomyrmex specimen embedded in Baltic amber was acquired by the Paleontological Museum of the University of Hamburg. This specimen shows unequivocally the presence of suberect hairs on the scapes (Fig. 2) confirming in this way the presence of two different species of Prionomyrmex in Northern Europe during Oligocene. A more detailed analysis and description of the latter specimen are in preparation.

References

Baroni Urbani, C. 2000. Rediscovers of the Baltic amber ant genus Prionomyrmex (Hymenoptera, Formicidae) and its taxonomic consequences. Eclogae geol. Helv. 93: 471-480.
Mayr, G. L. 1868. Die Ameisen des baltischen Bernsteins. Beitr. Naturkunde Preuss., 1: 1-102, 5 pl.
Wheeler, W. M. 1915. The ants of the Baltic amber. Schrift. Phys.-ökon. Ges Königsberg i. Pr., 55: 1-142.

FIGURES

Fig. 1. Prionomyrmex janzeni Baroni Urbani from Baltic amber. General appearance of the worker in dorsal view (reproduced from Baroni Urbani, 2000).
Fig. 2. Prionomyrmex longiceps Mayr. Worker from Baltic amber. Micrograph of the right scape and first funicular joints showing the presence of suberect hairs. Distance between the scale bars 0.01 mm.