Rafel_93 Posted February 22, 2011 Share Posted February 22, 2011 Hi!! This is my first topic in the ID section, so I hope I've done everything well. Those are some fossils of the same specie of ammonite. They all are found in limestone from the lower cretaceous (barremian) -I know that because I found them with Barremites difficilis, and I think that these others are from the barremian, aren't they? Well, seeking with the google, I've found some similar species of the genus Berriasella, and I wanted to know if somebody could tell me if I'm right. Thanks very much! Link to comment Share on other sites More sharing options...
Aramon Posted February 22, 2011 Share Posted February 22, 2011 (edited) Hello! Your ammonites are not Berriasella (which are from Berriasian and not Barremian), but rather Pseudothurmania from Uppermost Hauterivian. This is very interesting! Have you got pics of the Barremites? The species Barremites difficilis is only present in the Upper Barremian, but there are other species of this genus Edited February 22, 2011 by Aramon Link to comment Share on other sites More sharing options...
Rafel_93 Posted February 22, 2011 Author Share Posted February 22, 2011 (edited) Hello! Your ammonites are not Berriasella (which are from Berriasian and not Barremian), but rather Pseudothurmania from Uppermost Hauterivian. This is very interesting! Have you got pics of the Barremites? The species Barremites difficilis is only present in the Upper Barremian, but there are other species of this genus Thank you SO much for helping me to classify those ones I put some pics of ammonites that I think that are Barremites (I've only seen a few images in the internet and I think that they can be those...). I have found them in the same rocks than the Pseudothurmania. Thanks so much again for helping me!! Edited February 22, 2011 by Rafel_93 Link to comment Share on other sites More sharing options...
Aramon Posted February 22, 2011 Share Posted February 22, 2011 I think you're right : those are effectively of the genus Barremites (The very close genus Plesiospitidiscus is also present at this level). Link to comment Share on other sites More sharing options...
Rafel_93 Posted February 22, 2011 Author Share Posted February 22, 2011 Thanks! I also found this other specie (well, it's only a broken one, I found it like that), but I think that's a Crioceratites? It's also found in the same rocks. Probably I'm wrong, and probably it'll be hard to identify because it isn't the complete specimen, but anyway... I've also found Aptychus and belemnites there, I'll upload pics later.. ^^ Link to comment Share on other sites More sharing options...
Aramon Posted February 22, 2011 Share Posted February 22, 2011 Yes, it is probably a Crioceratites, but are you sure all the specimens you have posted are exactly from the same level? Because this last is usually a bit more older normally... Link to comment Share on other sites More sharing options...
Rafel_93 Posted February 22, 2011 Author Share Posted February 22, 2011 Well, I found them in a mountain with a lots of rocks, so maybe this rock could have fallen from an upper level... (They weren't on a wall but in separate rocks that were very near). But when I found them, all the pictures that I have posted so far except the first Barremites were exactly in the same place (I found that one some metres away) Link to comment Share on other sites More sharing options...
Aramon Posted February 23, 2011 Share Posted February 23, 2011 Ok! Thanks for the explanations! In fact, in certain cases a few meters could be suficiant to change the age of the rocks. It depends on the sedimentary trends, on the geology of the outcroup, and on the presence of faults, etc. So this is really important to locate the fossils very precisely when extracting them, if possible "at the level" (bed-by-bed tracking) Link to comment Share on other sites More sharing options...
Rafel_93 Posted February 23, 2011 Author Share Posted February 23, 2011 Ah, ok, I understand... It's true that I've found Pseudothurmania and Barremites in the same piece of rock, while I found Crioceratites in another piece (although they were very close) that may had come from another level. Thanks so much!! So, I can label they as: 1st pics - Pseudothurmania from Uppermost Hauterivian 2nd pics - Barremites (difficilis?) from Barremian 3rd pic - Crioceratites from (?) ? Many thanks for helping me so much!!! :bow: Link to comment Share on other sites More sharing options...
Aramon Posted February 23, 2011 Share Posted February 23, 2011 (edited) So, I can label they as: 1st pics - Pseudothurmania from Uppermost Hauterivian 2nd pics - Barremites (difficilis?) from Barremian 3rd pic - Crioceratites from (?) ? Well, if the Pseudothurmania AND the Barremites come from the same level, they probably have the same age (but not inevitably). To have a better determination of your Barremites a ventral view is needed as a better preping (if possible) The genus Crioceratites is present in almost the whole Hauterivian so... And your specimen is not sufficiently well preserved for being reliably determined and to know its exact age, but "Upper Hauterivian" would be correct I think. Edited February 23, 2011 by Aramon Link to comment Share on other sites More sharing options...
Rafel_93 Posted February 23, 2011 Author Share Posted February 23, 2011 I see... Yes, Pseudothurmania and Barremites are exactly of the same level. And I'm sorry, I'm afraid I cannot do a better preparation.. mainly because of two facts: -I don't really know how to do a good preparation (I know I have to learn it, but I don't know how) -The rock is so hard and the ammonite is so compressed (and fragile, it brokes when you touch it) that when I try to improve the preparation it brokes even more... And also sorry about my ignorance and my lack of vocabulary but... which part of the shell is called ventral? Thank you so much! Link to comment Share on other sites More sharing options...
Aramon Posted February 23, 2011 Share Posted February 23, 2011 (edited) I see... Yes, Pseudothurmania and Barremites are exactly of the same level. And I'm sorry, I'm afraid I cannot do a better preparation.. mainly because of two facts: -I don't really know how to do a good preparation (I know I have to learn it, but I don't know how) -The rock is so hard and the ammonite is so compressed (and fragile, it brokes when you touch it) that when I try to improve the preparation it brokes even more... Well there are many methods for preping fossils. Personally I use a "compressed air pencil", but surely you'll find good explaination about preping on the forum And also sorry about my ignorance and my lack of vocabulary but... which part of the shell is called ventral?Thank you so much! In fact the views you provide are the laterals. The ventral side of the ammonite is the edge of the shell (I don't know if it is the good English...) in respect to its life position (like the Nautilus). I don't know if my explanations are very clear? Edited February 23, 2011 by Aramon Link to comment Share on other sites More sharing options...
Rafel_93 Posted February 23, 2011 Author Share Posted February 23, 2011 (edited) Yes, I think I've understood that... Is it the part where the "head" should be, isn't it? Well... those Barremites are so fragile that I've always broken that part... If I cand find one (I have about 7 or 8 of them) whose ventral side can be seen I'll photography it as soon as I can (I'm afraid I won't find any...) Thanks! ^^ Edited February 23, 2011 by Rafel_93 Link to comment Share on other sites More sharing options...
Aramon Posted February 23, 2011 Share Posted February 23, 2011 Yes! This is it! "Where the head should be" and the back edge! If the ammonites are broken, you can stick them with some glue Link to comment Share on other sites More sharing options...
Rafel_93 Posted February 24, 2011 Author Share Posted February 24, 2011 I'll take those photos if I find one less "grainy", because the keel or the ventral side can't be appreciated well in those ones... Thanks! Link to comment Share on other sites More sharing options...
Rafel_93 Posted February 24, 2011 Author Share Posted February 24, 2011 One last thing... Are these others Pseudothurmania too? The last one is the keel of an ammonite exactly the same than the two middle photos. The first is only a mould, and I don't know if its Pseudothurmania's (If I'm being a pain in the neck please just tell me) Link to comment Share on other sites More sharing options...
Rafel_93 Posted February 24, 2011 Author Share Posted February 24, 2011 More photos that I couldn't fit in the other message. I forgot to say that I haven't found these others in the same place than Psaudothurmania, so they can even don't be cretaceous at all. The last photo shows the rock of the Pseudothurmania of the 3rd pic of the 1st post upside-down. Can it be an Aptychus? Thanks for everything!! ^^ Link to comment Share on other sites More sharing options...
Aramon Posted February 25, 2011 Share Posted February 25, 2011 (edited) One last thing... Are these others Pseudothurmania too? The last one is the keel of an ammonite exactly the same than the two middle photos. The first is only a mould, and I don't know if its Pseudothurmania's (If I'm being a pain in the neck please just tell me) The first one in not a Pseudothurmania. I rather think a Berriasella from Berriasian, or a Neocomitidae (?) of the Lower Valanginian (but without conviction, I don't know very well these levels). The second one is unidentifiable, sorry. The third and the fourth are the same? Because the third looks like Jurassic Perisphintidae and these have no keel usually. Edited February 25, 2011 by Aramon Link to comment Share on other sites More sharing options...
Aramon Posted February 25, 2011 Share Posted February 25, 2011 More photos that I couldn't fit in the other message. I forgot to say that I haven't found these others in the same place than Psaudothurmania, so they can even don't be cretaceous at all. The last photo shows the rock of the Pseudothurmania of the 3rd pic of the 1st post upside-down. Can it be an Aptychus? Thanks for everything!! ^^ The first really looks like a Perisphinctidae (Kimmeridgian???). I don't think this is Cretaceous... The specimens on the second photo are both unidentifiable, sorry... Yes, the third is an Aptychus! Link to comment Share on other sites More sharing options...
Rafel_93 Posted February 25, 2011 Author Share Posted February 25, 2011 Well, thank you so much for helping me to identify that ones!! I have consulted at a geological map but in that area only says that's Mesozoic (I already knew that XD) Link to comment Share on other sites More sharing options...
Aramon Posted February 25, 2011 Share Posted February 25, 2011 If you find other ammonites, perhaps it will be possible to have a better datation, and thus a better determination Link to comment Share on other sites More sharing options...
Rafel_93 Posted February 25, 2011 Author Share Posted February 25, 2011 Yes... but those last few ammonites are from an area of cultivated land, so all the rocks (very little pieces of rock) are mixed with earth and it's hard to determinate a level.. I also found a Cerastoderma shell (bivalve) near those ammonites... Well, at least they are of the order Ammonitida, aren't they? (At least I won't have an empty ID paper ) Link to comment Share on other sites More sharing options...
Aramon Posted February 25, 2011 Share Posted February 25, 2011 Well, at least they are of the order Ammonitida, aren't they? (At least I won't have an empty ID paper ) Yes, at least they are Link to comment Share on other sites More sharing options...
Rafel_93 Posted February 25, 2011 Author Share Posted February 25, 2011 Thanks!! (Now I was doing the labelling) The Pseudothurmannia can be baleare? (Or balearic, because I googled the name and in both there was the same ammonite). I say it because it's the one that's most alike to my shells... And I forgot to post two things that I found along with the first ammonites (Pseudothurmannia and Barremites) Any idea of what can they be? Link to comment Share on other sites More sharing options...
Aramon Posted February 25, 2011 Share Posted February 25, 2011 (edited) Yes : the first photo is part of a bivalvia which I forgot the name (lol), and the second is probably a very little fragment of an ammonite (?). Well, are your specimens trituberculated in the innermost whorls? If this is the case they could be Balearites baleare (on my opinion baleare species is not a true Pseudothurmania). But the first photo of your first post really looks a Pseudothurmania s. str. (like P. ohmi or P. pseudomalbosi). For the other specimens it's hard to say. If you can make photos with an oblique light to hightlight the ornamentation it will be easier to answer An other argument for the Pseudothurmania identification rather than Balearites is there is no Barremites in the Baleare Zone, they appear only in the Uppermost Hauterivian with Pseudothurmania s. str. Edited February 25, 2011 by Aramon Link to comment Share on other sites More sharing options...
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