ynot Posted June 27, 2016 Share Posted June 27, 2016 Hey Y'All, Found this C. Hastalis on My last trip to Sharktooth Hill (story here--http://www.thefossilforum.com/index.php?/topic/66149-hot-days-and-toothy-dreams/ ) I think it looks laterally compressed, but would like to get Your opinions on it. What do You think-- pathologic or not? Scale in picture is inch ruler. Thank Y'All for any opinions!! Tony Link to comment Share on other sites More sharing options...
doushantuo Posted June 27, 2016 Share Posted June 27, 2016 (edited) I am a total newbie. Nice to know i am seeing a hastalis,but what's the genus? "Sharktooth Hill " gives me reason to believe it's an elasmobranch Edited June 27, 2016 by doushantuo Link to comment Share on other sites More sharing options...
ynot Posted June 27, 2016 Author Share Posted June 27, 2016 I am a total newbie. Nice to know i am seeing a hastalis,but what's the genus? "Sharktooth Hill " gives me reason to believe it's an elasmobranch The genius keeps changing but I think this is the current placement. Cosmopolitodus (Isurus) hastalis (AGASSIZ, 1843) extinct White shark You may like this site... http://elasmo.com/ Tony Link to comment Share on other sites More sharing options...
doushantuo Posted June 27, 2016 Share Posted June 27, 2016 (edited) I take it selachian teeth are NOT normally laterally compressed? BTW:Isolated teeth and taxonomy don't sit well together. E.g. think sexual dimorphism,ontogenetic differences,intraspecific variation and teratologies Thanks for thinking of showing a link. Edited June 27, 2016 by doushantuo Link to comment Share on other sites More sharing options...
ynot Posted June 27, 2016 Author Share Posted June 27, 2016 I take it selachian teeth are NOT normally laterally compressed? BTW:Isolated teeth and taxonomy don't sit well together. E.g. think sexual dimorphism,ontogenetic differences,intraspecific variation and teratologies Thanks for thinking of showing a link. This is a C. Hastalis tooth that has the typical appearance from this species. Do not understand this statement. Other than upper/lower differences, as for as I am aware the only difference is an age thing. The teeth become more robust as the shark gets older. Tony Link to comment Share on other sites More sharing options...
doushantuo Posted June 27, 2016 Share Posted June 27, 2016 (edited) Ontogeny is the scientific term for the process of maturation/growing up,and that means,of course,size changes,but also shape changes. sexual dimorphism: the differences between males and females All species of animals and plants are variable,to different degrees. That's the reason in most differential diagnoses of species the maximum and minimum sizes encountered are mentioned,as well as other differences. A lot of species ,particularly in paleontology are based on statistical differences Edited June 27, 2016 by doushantuo 1 Link to comment Share on other sites More sharing options...
Coco Posted June 27, 2016 Share Posted June 27, 2016 Hi, Do not understand this statement. Other than upper/lower differences, as for as I am aware the only difference is an age thing. The teeth become more robust as the shark gets older. Tony Have a look on this thread ! http://www.thefossilforum.com/index.php?/topic/10818-heterorodontie-of-selachians/?hl=%2Bshark+%2Bjaw Coco 1 ---------------------- OUTIL POUR MESURER VOS FOSSILES : ici Pareidolia : here Ma bibliothèque PDF 1 (Poissons et sélaciens récents & fossiles) : ici Ma bibliothèque PDF 2 (Animaux vivants - sans poissons ni sélaciens) : ici Mâchoires sélaciennes récentes : ici Hétérodontiques et sélaciens : ici Oeufs sélaciens récents : ici Otolithes de poissons récents ! ici Un Greg... Link to comment Share on other sites More sharing options...
ynot Posted June 27, 2016 Author Share Posted June 27, 2016 Thanks for the information! I was unaware of the names of the different types of dymorfizm. My statement-- "Other than upper/lower differences, as for as I am aware the only difference is an age thing. The teeth become more robust as the shark gets older." -- was in regards to the C. Hastalis, not for sharks in general. Tony PS Still looking for an opinion on the pathologic thing. Link to comment Share on other sites More sharing options...
ynot Posted June 28, 2016 Author Share Posted June 28, 2016 137 views and no opinions on the pathology. Does anyone have an opinion about this? Tony Link to comment Share on other sites More sharing options...
Troodon Posted June 28, 2016 Share Posted June 28, 2016 Tony I would lean towards it being a patho. 1 Link to comment Share on other sites More sharing options...
doushantuo Posted June 28, 2016 Share Posted June 28, 2016 I'd consult Gudger Link to comment Share on other sites More sharing options...
siteseer Posted June 28, 2016 Share Posted June 28, 2016 (edited) Tony, Lateral compression would show in the root lobes first since they extend farther laterally than the crown. Without the root it's hard to say but I don't see any sign of the cutting edges being pressured from either side. If you don't see many lower teeth, and then you find one, it can look weird. Jess 137 views and no opinions on the pathology. Does anyone have an opinion about this? Tony Edited June 28, 2016 by siteseer 2 Link to comment Share on other sites More sharing options...
ynot Posted June 28, 2016 Author Share Posted June 28, 2016 Tony I would lean towards it being a patho. Thank You! I'd consult Gudger Who is that? Tony, Lateral compression would show in the root lobes first since they extend farther laterally than the crown. Without the root it's hard to say but I don't see any sign of the cutting edges being pressured from either side. If you don't see many lower teeth, and then you find one, it can look weird. Jess So You think it is a lower? I thought it an upper. Thanks for the knowledge! Tony Link to comment Share on other sites More sharing options...
siteseer Posted June 30, 2016 Share Posted June 30, 2016 Tony, First, it's really big for a partial crown of that species so we can assume it's from an individual well into adulthood. As Coco showed, upper teeth in sharks tend to be curved or angled while the lowers tend to be straighter, the first lower position tending to be the straightest tooth - not always) but sometimes curved or angled (but not as curved as uppers can be). Nature often frustrates the human urge to define and categorize and perhaps never more so than with shark teeth. I can only say that the more teeth you get a chance to look at, the more you understand some of the variation within a species, variation at each jaw position. You would have to look around for proposed C. hastalis dentitions or at least some identified lower anteriors so you get familiar with the shapes. Also, look at modern great white jaws when you can. Look at as many modern shark jaws as you can (Marco Sr.'s recent threads are a great free education). Check out elasmo.com's coverage of great white evolution. Acquire as many shark articles as you can and learn which of the fossil shark tooth guides are more helpful than the others (but buy some of the less helpful ones for fun too). After all that, you will get an idea of how to identify hastalis teeth and most of the other shark teeth you see down to genus with varying levels of confidence but sometimes you will be wrong and as confused as when you started. Jess Thank You! Who is that? So You think it is a lower? I thought it an upper. Thanks for the knowledge! Tony 1 Link to comment Share on other sites More sharing options...
doushantuo Posted June 30, 2016 Share Posted June 30, 2016 THIS gudger http://www.thefossilforum.com/index.php?/topic/66287-monograph-by-gudger-on-pathologies/ 1 Link to comment Share on other sites More sharing options...
siteseer Posted July 6, 2016 Share Posted July 6, 2016 Yes, that is probably the first published article on pathologic shark teeth. You should be able find this too (interesting article): Becker, M.A, J.A. Chamberlain Jr., and P.W. Stoffer. 2000. Pathologic tooth deformities in modern and fossil chondrichthians: a consequence of feeding-related injury. Lethaia 33: 103-118. THIS gudger http://www.thefossilforum.com/index.php?/topic/66287-monograph-by-gudger-on-pathologies/ 1 Link to comment Share on other sites More sharing options...
mrieder79 Posted July 6, 2016 Share Posted July 6, 2016 I would consider it borderline. It is definitely narrower than most hastalis teeth, many even. I guess some of it comes down to sematntics and where someone wants to draw the line with variable morphology and definite pathology. 1 Luck is the most important skill of a fossil diver. Link to comment Share on other sites More sharing options...
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