Wednesday, June 23, 2010

Gozo crocodiles


The picture above shows a fossil skull of the Miocene crocodilian Tomistoma gaudensis (Hulke, 1871) from the Globigerina Limestone of Gozo. This specimen is located at the National Museum of Natural History, Mdina, reg. no. NMNH-T11228. Another species, namely Tomistoma champsoides (Owen in Hulke, 1871) is also known to have occurred in the area now occupied by the Maltese Islands.

Reference:

Hulke, J. W., 1871. Note on some reptilian fossils from Gozo. Quarterly Journal of the Geological Society, 27 (1-2): 29-33.

4 comments:

  1. Hi David Cilia,

    Interesting to know that crocs once live in the Mediterranean. Malta must have been a wetter area with plenty of swamplands many eons ago. Are there any paleo-molluscs of the same era discovered as well?

    Best,
    JK

    ReplyDelete
  2. Hi JK :)

    The environment was probably ocean-like because the rock is composed mainly of foraminifers. Palaeomolluscs found in the same layer in fact include Epitonium, Vaginella, Gamopleura and other 'deep-sea' species.

    It's still not well understood how fossils of crocodiles found themselves here. Crocodiles can swim, but then even Mastodon teeth were found; this is quite an anomaly with our current knowledge!

    PS This is not a true crocodile but a 'false gharial', the likes of which can now be found in Borneo and China. It ties in with the fact the the area now having the Mediterranean in it was 'open' from the east side, allowing fauna like this and also other Indopacific genera (Kuphus, Strombus, Conus, etc etc) to be found as fossils here.*

    *Zammit Maempel, G., 1969. The Indo-Pacific affinity of some Maltese Tertiary fossils. The Central Mediterranean Naturalist, 1 (1): 1-12.

    Best regards
    David

    ReplyDelete
  3. Hi David Cilia,

    Just a wild guess: Malta could be a deep area (canyon/deep drop-off perhaps?) off a paleo-estuary. hence, the findings of land and freshwater fauna remains washed into the bottom of the deep canyon areas.

    Or another possibility: A tsunami swept away the terrestrial and freshwater fauna and brought them to deeper waters, where they died and sink to the bottom?

    Best,
    JK

    ReplyDelete
  4. The freshwater and land fauna is unusual as the Maltese Islands were part of the Mediterranean basin. Some suggest that there were periods when the land rose out of the ocean and then sank again, this would explain certain ripple marks of waves in some strata.

    The Mastodon could have been a corpse floating off from a nearby landmass (which is possible and also explains 'swimming' crocodiles). Only teeth of Mastodon have been found, and only once, so it was a very coincidental occurrence.

    As for the paleo-estuary hypothesis it does not strike me as correct because of the lack of evidence - I would imagine at least a few freshwater mollusc fossil if that were the case, but these are completely absent.

    ReplyDelete

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