PSYCHE 
Vol. 94 
1987 
No. 1-2 
THE FOSSIL MEMBERS OF THE ANT TRIBE 
LEPTOMYRMECINI (HYMENOPTERA: FORMICIDAE) 
By Cesare Baroni Urbani 1 and Edward O. Wilson 2 
In 1980 Baroni Urbani described Leptomyrmex neotropicus from 
9 rather poorly preserved specimens clustered in a single piece of 
Dominican amber and hence presumed to be of Miocene age (the 
date estimated in Baroni Urbani and Saunders, 1982). The finding is 
of potential biogeographic importance because Leptomyrmex, and 
hence the very distinctive dolichoderine tribe Leptomyrmecini, is 
today limited to the Old World, in particular eastern Australia, New 
Caledonia, New Guinea, the Aru Islands, and the Moluccas. A 
second genus, Leptomyrmula, had previously been described from 
the Miocene amber of Sicily (Emery, 1891, 1912). It thus appears 
that an entire tribe was once almost worldwide but has since 
retreated not only from Europe but the entire Western Hemisphere. 
Wilson (1985a) doubted Baroni Urbani’s tribal placement of the 
Dominican amber specimens. He found a worker in Dominican 
amber that superficially resembles Leptomyrmex, sharing the same 
distinctively elongated body form, mesothoracic constriction, peti- 
ole, tapered neck, and bulging eyes located toward the rear of the 
head, but actually belongs to the Camponotus branneri group. He 
suggested that Leptomyrmex neotropicus might be the same species. 
In the meantime, Schlee (1984) published a color photograph of 
another Dominican amber piece containing four presumed Lepto- 
myrmex workers. This example is now preserved in the collection of 
'Zoologisches Institut der Universitat Basel, Rheinsprung 9, CH-4051 Basel, 
Switzerland. 
2 Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 
02138, USA. 
Manuscript received by the editor February 17, 1987. 
