oilshale Posted November 11, 2010 Share Posted November 11, 2010 (edited) The palaeoenvironment of Monte Bolca Lagerstätte was reconstructed as a basin or a sub-tropical lagoon, close to land and connected to rivers and wetlands. This basin showed phases of opening to the sea and phases of enclosure and isolation. During the "closed" phases, living conditions such as high(er) salinity and low(er) oxygen content in the bottom explained the exceptional conditions of fossilization and the absence of benthic fauna and scavengers. Worsening living conditions could also result in a higher percentage of fish infected by parasits. Their presence should reflect an unbalanced palaeoenvironment in the basin where the fishes of the "Pesciara di Bolca" fossilized. The collection of fossil fishes from Monte Bolca (Eocene of Northern Italy), deposited at the Museum national d'Histoire naturelle, Paris, was examined by Gilles Petit for the detection of parasites or traces of their activity. Of the 349 fishes studied, 62 showed a fairly well-preserved integument for the observation and 9.6% out of them showed skin-nodules. I am not sure, but I think this Pseudosparnodus microstomus had the same problem: Here is a close-up of it's ventral and abdominal region showing several skin nodules (at least that's what I believe): This is a close-up out of G. Petits original paper: And this is a living species with skin nodules (also out of G. Petits original paper): Here is the original paper from G. Petit Thomas Edited March 13, 2021 by oilshale 1 Be not ashamed of mistakes and thus make them crimes (Confucius, 551 BC - 479 BC). Link to comment Share on other sites More sharing options...
Auspex Posted November 11, 2010 Share Posted November 11, 2010 An interesting pathology, and a tantalizing window into the paleoecology of the site. This shows the value in really looking at your specimens. Great fossil, BTW! "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
fossil lover 101 Posted November 11, 2010 Share Posted November 11, 2010 cool! Link to comment Share on other sites More sharing options...
Frank Menser Posted November 12, 2010 Share Posted November 12, 2010 Dang! my collection is in boxes Gives me something to look for when I unpack Be true to the reality you create. Link to comment Share on other sites More sharing options...
dsalles Posted February 2, 2011 Share Posted February 2, 2011 Fossils with pathologicals problems? Great topic Thomas! Anybody with other pathologic material? Deformed shark teeth? Sea urchins or star fish with non unusual symmetrie? Once I saw a recent starfish with 4 arms (not just one arm missing - with 4-fold symmetrie!), crinoids with regenerated arms, deformed brachiopods? Would be interesting to see! Daniel Link to comment Share on other sites More sharing options...
Terry Dactyll Posted February 2, 2011 Share Posted February 2, 2011 Thomas... Interesting topic and nice examples... is this due to argulus type parasites?... This ammonite shell I recently cleaned demonstrates "forma inflata" below the last complete ribs and I am informed it's probably due to parasitism of some description... Cheers Steve... And Welcome if your a New Member... Link to comment Share on other sites More sharing options...
oilshale Posted February 2, 2011 Author Share Posted February 2, 2011 Thomas... Interesting topic and nice examples... is this due to argulus type parasites?... This ammonite shell I recently cleaned demonstrates "forma inflata" below the last complete ribs and I am informed it's probably due to parasitism of some description... Could be of Argulus type (= fish lice, sort of branchiuran crustaceans) or due to other pathogens among the group of viruses, bacteria and so on. But the relatively high proportion in this population seems toreflect an unbalanced palaeoenvironment in the basin where the fishes of the “Pesciara di Bolca” fossilized. Never seen it before - nice ammonite monstrosity! "Forma inflata" was described by Keupp 1976. According to him, the deformed bulbous protrusion from the shell is probably the result of a bite through some portion of the body chamber and a subsequent rupture of the mantle through the broken shell. A similar type of deformity has also been observed in extant Nautilus. Thomas Be not ashamed of mistakes and thus make them crimes (Confucius, 551 BC - 479 BC). Link to comment Share on other sites More sharing options...
fossilshk Posted February 2, 2011 Share Posted February 2, 2011 Thanks for sharing! ! Dinosaur Fossil Lab http://www.fossilshk.com Link to comment Share on other sites More sharing options...
Terry Dactyll Posted February 3, 2011 Share Posted February 3, 2011 ''Never seen it before - nice ammonite monstrosity! "Forma inflata" was described by Keupp 1976. According to him, the deformed bulbous protrusion from the shell is probably the result of a bite through some portion of the body chamber and a subsequent rupture of the mantle through the broken shell. Thomas'' Thanks... its not as obvious from the front elevation how deformed it actually is... Cheers Steve... And Welcome if your a New Member... Link to comment Share on other sites More sharing options...
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