Snakes
from the Eocene of India were diverse. Jean-Claude Rage (2002) reported on the
early Eocene serpent fauna of India using fossils from the Panandhro Mine in northwestern
India. This locality produced a rich snake fauna that was dominated by the
highly aquatic palaeophiids. Rage found three families represented in the
fossil beds: the aquatic Palaeophiidae; fossils that may be ?Madtsoiidae or
Boidae; and a representative of the Colubroidea.
The Palaeophiidae include remains of two species: Pterosphenus kutchensis and
Pt. biswasi .They are the earliest known representatives of the
genus. Madtsoiidae (or Boidae) were represented by two specimens that do not
permit distinction between these two families. If the fossils belong to the
Boidae, they would be the earliest representatives of that family in Asia. And
the colubroid snake from this site ranks among the earliest Cenozoic
representatives of the clade. The possibility that it belongs to the Colubridae
could not be eliminated – it had a very light build. If true it would be the
earliest known snake in the family Colubridae. Nearly all fossil specimens at
the mine belonged to Pterosphenus, a highly aquatic genus. It lived in
shallow water, probably in marine environment close to the coasts or in
freshwater. In a second paper, Rage and colleagues (2008) reported on a second
India early Eocene fossil site, the Vastan Lignite
Mine in Gujarat, western India. The fossils included at least 10 species that
belong to the Madtsoiidae; Palaeophiidae (Palaeophis and Pterosphenus);
Boidae; and several Caenophidia. The
Colubroidea were represented by Russellophis crassus. (Russellophiidae)
and by Procerophis sahnii. As well as Thaumastophis missiaeni a caenophidian of uncertain family
status. The authors write, “The number of taxa that represent the Colubroidea
or at least the Caenophidia, i.e., advanced snakes, is astonishing for the Eocene.
This is consistent with the view that Asia played an important part in the
early history of these taxa.” The Vastan
Mine fossils come from marine and continental levels
and includes highly aquatic, amphibious, and terrestrial snakes. The
composition of the fauna from Vastan seems similar to that of the more poorly
known early Eocene of Europe.
Also
consider the recent discover of Sanajeh
indicus by Wilson et al. 2010. Sanajeh was from the very late Cretaceous and found
near Dholi Dungri village in Gujarat, Western India. Sanajeh indicus was
preserved in a sauropod dinosaur nesting ground associated with eggs and a
hatchling sauropod. The new fossils provided the first evidence of snake
predation on hatchling dinosaurs.
Thus the time span between late Cretaceous and
the early Eocene of India appears to have been rich is snake species. Today there
is evidence to suggest that India had the oldest tropical forests known
during this time. Rust et al. (2010), describe the Cambay amber of Gujarat, in western India and fossilized wood
as the oldest evidence for tropical forests in Asia. The amber has been
chemically linked to dipterocarps (Dipterocarpaceae), a family of hardwood
trees that today make up 80 percent of the forest canopy in Southeast Asia. The
fossilized wood from this family makes this deposit the earliest record of
these plants in India and demonstrates that the family is nearly twice as old
as was commonly believed. The forest was like to have been present when
portions of the southern supercontinent Gondwana were still connected. The
paper also describes 100 species of arthropod representing 55 families and 14
orders. Some of these species are early relatives of highly social, or
eusocial, insects like honey bees and stingless bees, rhinotermitid termites,
and ants, suggesting that these groups radiated during or just prior to the
early Eocene. Many of the Cambay fossils have relatives on other
continents—although not where it would be expected. Rather than finding
evolutionary ties to Africa and Madagascar, landmasses that India had most recently been
linked to as part of Gondwana, the researchers found relatives in Northern
Europe, Asia, Australia, and the Americas.
References
Rage J.-C.,
Bajpai S., Thewissen J. G. M. & Tiwari B. N. 2003. — Early Eocene snakes
from
Kutch, Western
India, with a review of the Palaeophiidae. Geodiversitas
25 (4):695-716.
Rage, J.-C., A. Folie, R. S. Rana, H. Singh, K. D. Rose, T.
Smith. 2008. A Diverse Snake Fauna from
the Early Eocene of Vastan Lignite Mine, Gujarat, India. Acta
Palaeontologica Polonica, 53 (3):391-403.
Rust, J., H. Singh, R. S. Rana, T. McCann, L. Singh, K.
Anderson, N. Sarkar, P. C. Nascimbene, F. Stebner, J C. Thomas, M. S. Kraemer, C.
J. Williams, M. S. Engel, A. Sahni, and D. Grimaldi 2010. Biogeographic and
evolutionary implications of a diverse paleobiota in amber from the Early
Eocene of India. PNAS published ahead
of print October 25, 2010, doi:10.1073/pnas.1007407107
Wilson J. A.,
Mohabey D,M., Peters S.E., Head J.J.
2010. Predation upon Hatchling Dinosaurs by a New Snake from the Late
Cretaceous of India. PLoS Biol 8(3):
e1000322. doi:10.1371/journal.pbio.1000322