A fairly long migration!

Background

'Out of Africa' theory for America's crocodiles

The several species of crocodiles plying rivers and brackish byways in the Americas - from Florida to Peru - all came from Africa, according to a new study published in the journal 'Scientific Reports'.

1. How did the crocodiles reach America?

Prior to this discovery it was unclear whether the crocodiles reached the Americas from Africa, via a hypothesised  transatlantic voyage or vice versa.

Researchers speculate that they may have descended from a single pregnant specimen that bobbed along Atlantic Ocean currents to the New World at least five million years ago, probably longer.

"This is a really exciting discovery. It supports the results of molecular biologists that proposed the origin of American crocodiles had to be found in Africa".  

 - Massimo Delfino from the University of Turin and Dawid Iurino from Sapienza University, lead authors.

2. Is such a journey possible?

Such a voyage is possible. It has been demonstrated by a present-day cousin, Australia's saltwater crocodile. Satellite tracking has shown that it can travel 500 km in about a month while passively transported by ocean current.

In 1939, a 10 centimetre skull fragment of Crocodylus checchiai - an ancient crocodile species - was unearthed from the Libyan desert.

3. CT Imaging

Researchers used CT-scans and 3D-modelling to re-examine the skull fragment stored at the Earth Sciences museum in Rome.

4. Close Relationship

This shared skeletal structure indicates a close evolutionary relationship Crocodylus checchiai and American crocodiles.

5. Important Findings

Crocodylus checchiai rewrites the story of how crocodiles spread across the planet in at least two ways:-

     * It lays to rest the already fading hypothesis that the giant, flesh-ripping reptiles - which first

        emerged from Asia - arrived in the Americas before moving on to Africa and not the other way

        around.

     * The long-neglected fossil also supplants another contender from Africa - Crocodylus niloticus,

        aka the Nile crocodile - as the closest forebear of the American species.

6. Comparisons With Living Species

They identified several new skull structures, including a protrusion in the middle of the snout that has not been identified on any other African crocodile species but that is present on the skulls of the four living American crocodile species : Crocodile intermedius, Crocodile moreleti, Crocodile acutus and Crocodile rhombifer.

My take.

I remember my visit to the Bhitarkanika Sanctuary in Orissa - the confluence of the Rivers Bhitarkanika and Brahminy - in '89 while I was posted in INS Chilka, as I punch in these thoughts!

Tailpiece.

Got up at 6, the chores and was ready by a half past 9. The monthly provisions were ordered from the department store close by.