86 
Psyche 
[March 
Five of the six families 1 of termites recognized by Emerson (1955) 
have a fossil record extending at least as far back as the Tertiary. In 
1967, Cretatermes carpenteri (Hodotermitidae) was found in an 
Upper Cretaceous deposit in Labrador (Fig. 1), a discovery which 
immediately placed the origin of the Isoptera no later than the 
Mesozoic — an extension of 45 million years from previously 
known specimens. In addition, the advanced phylogenetic position 
of Cretatermes provides evidence for a much earlier origin of the 
order than has formerly been recognized (Emerson, 1967). 
An examination of various fossil localities reveals a widespread 
termite fauna during the Tertiary Period (Table 1). The Termitidae 
are found in Miocene deposits of California and Germany; the 
Rhinotermitidae, Hodotermitidae, and Kalotermitidae are found at 
various Tertiary deposits throughout the United States and Europe; 
and the Mastotermitidae have the most widespread Cenozoic 
distribution of all, having been found at localities in the United 
States, Europe, South America, and Australia. This latter finding is 
highly intriguing because the family Mastotermitidae today has but 
one species, Mastotermes darwiniensis, which is restricted to north- 
ern Australia. 2 Emerson (1955) postulates that this widespread 
'The sixth family is the Serritermitidae — an aberrant taxon known from only one 
species. 
2 A look at past climatic shifts provides additional insight into the redistribution of 
the termites, particularly with respect to the Mastotermitidae, now solely restricted to 
Australia. Reconstructions of paleo-climatic patterns may be made fairly accurately 
on the basis of floral analyses (Reid and Chandler, 1933). The presence of Sequoia 
stumps in the Florissant Shales of Colorado provides evidence for warmer tempera- 
tures during the Oligocene (Emerson, 1969). Tiffney (1977) postulates on the basis of 
fossil angiosperm assemblages that temperatures in New England during the 
Oligocene were much more equable than at present — the temperatures ranging from 
26° C to 9° C in contrast to today’s 21° C to -10° C. Furthermore, extended frosts and 
hard freezes were unknown. In the more tropical climate of the Oligocene, colony 
activities were presumably carried out year round in a relatively warm, moist 
environment, explaining the widespread distribution of the Mastotermitidae during 
the Lower to Middle Tertiary. By the Late Miocene or Early Pliocene, the earth’s 
climate began shifting towards cooler temperatures with the rising level of the 
continental land masses and increasingly large polar ice caps. My hypothesis is that, 
unable to adapt to an increasingly colder climate, and possibly to a concomitant 
change in predator pressures, the Mastotermitidae began to die out during the 
Tertiary. And, because at this time the Termitidae were undergoing tremendously 
successful radiation in Africa and South America, the Mastotermitidae became 
geographically restricted to northern Australia, represented today by only one relict 
species, Mastotermes darwiniensis. 
