Tingamarra Alamitophis

Introduction

Alamitophis tingamarra was a small Eocene madtsoiid, an extinct family of primitive snakes known mainly from Gondwana. Madtsoiids have the longest fossil record of any group of snakes, with a record that stretches from about 90 million to 100,000 years ago. Madtsoiids were probably constrictors although their upper jaws were not particularly flexible (as they are in living constrictors).

Identification

Most madtsoiids were small, although some grew as large as a boid or python, and are characterized by many archaic features (particularly of the vertebrae) lost in modern snakes. Their jaws were more primitive than those of modern constrictors and they would have been less able to swallow larger prey.

Species of Alamitophis are distinguished by the following characters of the vertebrae:

• a relatively high neural arch and spine,
• narrow zygosphene (a process on the front of the neural arch in snakes and lizards)
• and form of the haemal keel.

Alamitophis tingamarra, the smallest member of the genus, differs from Patagonian Alamitophis species in characters of the vertebral centrum (body) and zygopophyses (vertebral processes). The slight angle of the zygopophyses in Alamitophis tingamarradistinguishes it from Alamitophis elongatus, where the angle is more steeply inclined.

Habitat

The Murgon fossil site during the early Eocene was a shallow swamp or lake. The vegetation and climate of the period have not yet been determined.

Distribution

Alamitophis tingamarra was found near the town of Murgon in southeastern Queensland. Two other Alamitophis species are known from Patagonia. Alamitophis, along with Patagoniophis (a second snake known from both Patagonia and Murgon) would have crossed Antarctica to reach Australia, possibly living at latitudes higher than any other squamates at that time. Madtsoiids were primarily Gondwanan in distribution (found in Africa, South America) although madtsoiid fossils have been found in France and Spain.

Feeding and diet

Alamitophis tingamarra, because of its small size, probably ate frogs, lizards and small mammals. Like other madtsoiids, Alamitophis was probably a constrictor, although the upper jaws of madtsoiids were not particularly flexible (as they are in living constrictors).

Life history cycle

Madtsoiids may have been live-bearers instead of egg-layers, since most snakes living in similar cool, high-latitude environments today are live-bearing. Madtsoiid fossils are often found in freshwater deposits, although they do not appear to have been fully aquatic (perhaps like many terrestrial snakes, they swam or foraged for food at the margins of streams or lakes).

Fossils description

Vertebrae and dentaries (lower jaws) of Alamitophis tingamarra have been found.

Evolutionary relationships

Alamitophis tingamarra is most closely related to other Alamitophis species from the Late Cretaceous of Patagonia. Alamitophis is also related to the more well known Yurlunggur and Wonambi naracoortensis, larger snakes from the Miocene and Pleistocene of Australia.

Madtsoiids are generally poorly known. In a recent study of near-complete skull, and lower jaw material of the Riversleigh madtsoiid Yurlunggur, madtsoiids were confirmed as extremely archaic snakes at the base of the snake radiation and outside of Serpentes (modern snakes). After the Eocene, madtsoiids survived only in Australia, long known as a refuge for many ancient plants and animals.

References

• Albino, A. M. 1986. Nuevos Boidae Madtsoiinae en el Cretacico tardio de Patagonia (Formacion Los Alamitos, Rio Negro, Argentina). pp. 15-21 in Bonaparte, J. F. (ed.) Simposio Evolucion de los Vertebrados Mesozoicos. Actas IV Congreso Argentino de Paleontología y Biostratigrafia. Mendeoza, Argentina.
• Scanlon, J. D. 1993. Madtsoiid snakes from the Eocene Tingamarra Fauna of eastern Queensland. Kaupia: Darmstädter Beiträge zur Naturgeschichte 3, 3-8.
• Scanlon, J. D. 2005. Australia's oldest known snakes: Patagoniophis, Alamitophis, and cf. Madtsoia (Squamata: Madtsoiidae) from the Eocene of Queensland. Memoirs of the Queensland Museum (Proceedings of the Conference of Australasian Vertebrate Evolution, Palaeontology and Systematics) Vol. 51, 215-23.
• Scanlon, J. D. 2006. Chapter 17: Origins and radiations of snakes in Australasia. Pp. 309-330 in Merrick, J. R., Archer, M., Hickey, G. M. and Lee, M. S. Y. (eds) Evolution and Biogeography of Australasian Vertebrates. Australian Scientific Publishing, Oatlands.
• Scanlon, J. D., 2006. Skull of the large non-macrostomatan snake Yurlunggur from the Australian Oligo-Miocene. Nature 439, 839-842.
• Scanlon. J. D. and Lee, M. S. Y. 2000. The Pleistocene serpent Wonambi and the early evolution of snakes. Nature 403, 416-420.
• Shine, R. 1985b. The evolution of viviparity in reptiles: an ecological analysis. pp. 605-694 in Gans, C. and Billett, F. (eds) Biology of the Reptilia Vol. 15. John Wiley and Sons, New York.