Gomez Farías

Right now, I am on a reserach trip in northeast Mexico – more precisely in the State of Coahuila, which borders Texas at Big Bend. We are visting several sites of palaeontological sites and Gomez Farías is one of them. The rocks we are interested in are of Late Jurassic age. The place is in the middle of nowhere. The mountain rim is named “Sierra de Jabali”. Just a dirt road across a train track brings you there. Hence, it is worth while: landscape, plants, animals are just great. The altitude is above 2000 metres. Turning rocks you find centipedes, scorpions, iguanas and geckoes, whip scorpions, camel spiders, black widows, tarantulas and other life forms that pleases any zoologist. The vegetation is breath taking after heavy rains there.

Red flower

Red flower

The geology shows impressively the Jurassisc Cretaceous boundary, probably is one of the best sections in the world. The Jurassic (Tithonian) site was excavated by phosporite miners and left open for ages. Around 2000, remnants of a pliosaur were excavated. Further filed word recovered the rest of the 10 metre pliosaur, but also ichthyosaurs, thalattossuchian crocodilians, vertebrae of a long necked plesiosaur and millions of ammonites and bivalves. The density of the site indicates a concentration Lagerstätte of the finest. More work is planned there.

We visited the site first time since long and found the dirt track dodgy in places.

Scolopendra spec.

Scolopendra spec.

Mastigoproctus giganteus

Mastigoproctus giganteus

Latrodectus mactans

Latrodectus mactans


12 Responses to “Gomez Farías”

  1. 1 Nathan Myers
    September 11, 2008 at 9:00 am

    Testing, testing… my last post vanished without a trace. On the off chance this gets through…

    Welcome, Dino.

  2. 2 Teddy
    September 23, 2008 at 5:22 pm


    Nice blog. Ifollow your works since the excavation of the monster of Aramberri, this impressive discovery.

    There is no more news about it and I would have a fem questions.

    Since, the specimen was actually 15 or 18 m long ? How much it would have weighed ?

    Was it really a juvenile ? If that’s true, how big was the adult, I’ve read source about one third larger.

    It is really the largest prehistoric predator known to Man ?

    Thanks you, take care and good continuation.


  3. 3 dinofrey
    September 24, 2008 at 5:53 am

    Bonjour Ted,

    merci pour les compliments à propos le blog. Pour le moment je peut dire que ce animal tenait entre 15 y 18 mètres. Le poid cést impossible à dire pour le moment, mais la préparataton continue. C´est très possible, que El Monstruo etait jeune, praceque les arches neurales ne sont pas fusés avec les corps du vertebrés, mais, peutêtre, c´est le resultat du pedomorphie. Les marques de mordure et les dimensions des dents de l´predateur sont indicatives pout un animal de plus que 15 mejor 12 metros. La preparation continue dans le Museo del Desierto in Saltillo, Coahuila.

    Nos vemos


    Desolé pour le Francais

  4. 4 Teddy
    September 24, 2008 at 10:33 am

    Okay thanks Dino, you can write in english, no problem.
    About the marks of bite, you’ve said that the animal was 12 m longer than the suposedly young pliosaur ?
    Richard Forrest thinks also it’s a paedomorphic…

    In this article from 2005 of the German research, it was said the agressor had teeth around 40 cm and its jaws would have been almost 5 m. Is that true ?

    Could you compare your Monster and the Svalbard Pliosaur ?

  5. 5 dinofrey
    September 26, 2008 at 5:52 am

    Good. So I´ll do. Now I am up in the north of Mexiko in Chihuahua to check collections and possible museums so I was offline for a while. Now back to the monster. Well there is a bite mark with a diameter of 60 mm in the horizontal branch of a 350 mm pteroid. The tooth penetrated from dorsally meaning that the crown alone must have had a length of about 400 mm. Then comes a root which is normally about two thirds the length of a pliosaur tooth and then you just must find the bones to accommodate the ting and do a bit of calculation. So much for the possible five metres. Concerning a pedomorphy I see no evidence from the material. The Svalbard pliosaur is also a huge thing, but our preparation is in progress, but we have contact to the Svalbard group and thus we must wait until rock is separated from bone….

  6. 6 ted
    September 27, 2008 at 11:01 am

    Okay thank you !

    And for the moment, do you know what was the closest parents of this animal.
    Does its kind could have been the largest predatory species in the history of Earth ?
    Did you know that the BBC was inspired by your discovery to give some credits for the 25 m Liopleurodon of their series (not the first one but the another, with Nigel Marven in adventurer).

    Based on your works, the superpredator Liopleurodon was inspired by the Monster of Aramberri : http://www.bbc.co.uk/science/seamonsters/factfiles/liopleurodon.shtml

    Have you done some works about the megalodon shark ?

  7. 7 ted
    September 27, 2008 at 12:30 pm

    Okay thank you.

    I’ve heard that the pliosaur was very similar to Kronosaurus, is that true ?

    These creatures were possibly the largest and mightiest predators of all time ?

    How really powerful were their jaws ?

  8. 8 dinofrey
    September 28, 2008 at 3:38 am

    Well, since we had in in the media it was referred to as Liopleurodon mostly. Kronosaurus is new. I will put up a post soon with detailed data about what we know and for the moment we know only a little because about 75% of the 14 tons are still unprepared, and that what is out of the matrix is in Linares and not here. So I cannot even provide the lateset immages of the thing. I would like to be cautious with any taxonomy for the moment. Each block yields more huge bones. So much is sure, however, there was a kronosaurid around in Mexico during Late Jurassic times. The problem is that the specimen with the best skull of Kronosaurus ever in the Queensland Museum in Australia is pending description since several years – and the claim is still blocked.

    Concerning the size and the traces and signs we have, the largest pliosaurs probably exceeded 25 metres in length. Their jaws were powerful enough to bite through a complete skull of another pliosaur and their huge temporal openings indicate a tremendous muscle mass to power the jaws. Thus, the Mesozoic was not the time to invent boats. Ichthyosaurs and crocs come up with predators, which reached a length between 15 an 20 metres, and, finally, Zeuglodon and the sperm whale are known to exceed 20 metres in length. Mosasaurs come up to 15 metres, which is also not bad. The follows the shark Carcharias megalodon, Dunkleosteus etc.

  9. 9 ted
    September 28, 2008 at 10:37 am

    Okay thank you !

    Hum I’m actually in Djibouti but I follow regulary the researchs about the prehistoric marine predators. I’ll indicate you some sources soon…

  10. 10 dinofrey
    September 28, 2008 at 9:14 pm

    Lookintg forward to hear from you. Have fun in Djibouti!

  11. 11 Ted
    September 29, 2008 at 12:33 pm

    Thanks, I’ll be back in france in few weeks…

    Just another question, about your estimate of the 40 cm teeth, you include in this the root or just the blade ?


  12. 12 teddy
    January 16, 2010 at 8:06 pm

    Hello Dr Frey

    Have you any news about your creature ?

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September 2008

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