Vorompatra Lore


from

Birds: Their Life, Their Ways, Their World

by Christopher Perrins & C.J.O. Harrison

(Reader's Digest, 1979: pp.173-174)

Ad Cameron's Aepyornis & one surprised MalagasyAEPYORNITHIFORMES

Extinct ostrich-like birds known only from Africa

ELEPHANT BIRDS--Aepyornithidae

The family Aepyornithidae is at present made up from four extinct genera: Eremopezus, Stromeria, Mullerornis and Aepyornis, and is placed within its own order Aepyornithiformes. This group, commonly referred to as the 'Elephant birds', belongs to the rather loose assemblage of flightless running birds1 collectively called the ratites, which includes the Ostrich, rheas, cassowaries, Emu and kiwis among our living bird fauna.

Eremopezus and Stromeria are thought to be the earliest representatives of the family, their remains having been found in Tertiary rocks of North Africa that are up to 60 million years old. Both genera have been described from single leg bones although fragments of egg shell, sometimes referred to as Psammornis, have been attributed to Eremopezus.

The remains of Aepyornis and the smaller Mullerornis are 2 million years old or less, having been found in Pleistocene and Holocene deposits of Madagascar. Their skeletons are well-known, and must have resembled the Ostrich in life. The head was small. The wings were reduced to mere vestiges, but the legs were long and powerful and used for running2. The foot, unlike that of the Ostrich, normally had four toes although the rear toe is sometimes absent3. The largest species, A. maximus (A. titan) attained a height of over 10ft(3m) and probably inspired some of the legends of the past such as that of the Rukh, or Roc of Sinbad the sailor and Marco Polo.

Ad Cameron's OTHER AepyornisDistribution. The whole family, except for a single record of Eremopezus from Arabia, appears to have been restricted to North Africa and Madagascar. Eremopezus is recorded from Eocene deposits of Egypt, Libya and Algeria that are about 40 million years old. The genus Stromeria is found in Egypt in rocks that are thought to be from the slightly younger deposits of the Lower Oligocene.

Aepyornis and Mullerornis are only known from Pleistocene and Holocene rocks of the island of Madagascar. The exact date of their extinction is not known, but dates acquired from some egg shells show that at least some species were still alive less than one thousand years ago4.

Eggs and Nests. The nests of the Madagascan aepyornithids probably resembled those of the present-day ratites. The eggs which are creamy-white, are still found buried in the sand on the shores where they were laid many thousands of years ago5. The largest known specimen measures 3ft (1m) in its largest circumference and its liquid content would have been over 2gal (4�5l) (sic--probable misprint for "7.5l") . It is possible that both Aepyornis and Mullerornis were used as a food source by man and eventually exterminated by him through over exploitation.

Composition. The exact relationship between Eremopezus and Stromeria of mainland Africa and Aepyornis and Mullerornis of Madagascar must remain in doubt until more complete material has been found. If the two Tertiary genera are indeed ancestral to the later forms then one can say that the concentration of species in Madagascar represented the last stand of the order which once had a wider distribution.

The interrelationships between the ratites have long puzzled zoologists as it is uncertain whether they are a natural group or merely an assemblage of unrelated forms that have followed parallel lines of evolution. It has been stated recently, however, that the ratites are related through a common ancestor from South America which, by successive invasions via the Antarctic6 before the breakup and migration of the continents into their present global positions, reached their final destinations. The Madagascan birds probably reached that island before its separation from Africa7.

Notes on this text

  1. "Running birds" is usually not meant to be taken literally; rather, it is used as a synonym for "flightless"...


  2. ...but the author seems to think Aepyornis actually ran--this does not seem likely, given the skeletal structure and the immense weight of the ratite.


  3. For Vorompatra anyway, there are only three toes on each foot.


  4. Indeed, Vorompatra may not have died out until as late as 1700.


  5. As was noted above, some of those eggs are considerably more recent.


  6. To the best of my knowledge, no evidence of ratites has been found in Antarctica--to be fair, it's not exactly an easy place from which to excavate fossils. Continuing research on that continent will be expected to yield more evidence for the Gondwana dispersal theory if it's correct.


  7. A puzzling lack of Madagascan ratite fossils older than two million years continues to undermine the Gondwana disperal theory.