Dogfish Identification

[Sélacien34]

Hello, those teeth came from the miocene of the southern of France. The first one is Premontreia distans without his lateral cusplets i think. Does someone knows the others ?

Edited July 8, 2013 by Sélacien34

[Al Dente]

Hello, those teeth came from the miocene of the southern of France. The first one is Premontreia distans without his lateral cusplets i think. Does someone knows the others ?

Hello Selacien34

Some of your teeth look a lot like lower anterior teeth of Chaenogaleus affinis.

[Sélacien34]

Hello Al Dente, and thank you very much for your answer. What you said is amazing because i was thinking about Scyliorhinus joneti and it seems that lower anterior of C. affinis and teeth of S. joneti are very close, there would be even no differences, according to the infos I could find. My teeth came from Loupian but in an other place in the southern of France, Cabrières, the teeth of C. affinis are described as having differences with the ones from Loupian : they show real lateral denticles and cutting edges goes lower. Would there be a confusion ? I mean, are C. affinis from Loupian would be S. joneti ? However the 2 species are present on the formation and i have found them. I have found lateral positions of C. affinis. But nothing helps me to determinate about the teeth i have presented here if it would be lowers anteriors teeth of C. affinis or S. joneti. If you or anyone knows more about this, i'm interested !

Edited July 11, 2013 by Sélacien34

[MarcoSr]

What about these teeth convinces you that they are a different genus or species? It is these specific differences that you must use to try to find out what they might be. The more micro teeth that I collect, and especially the more micro teeth that I collect from a specific site convinces me that a lot of the teeth that I thought were a different genus or species were just positional or individual variations or age variations or gender variations etc. It is very difficult to speculate about individual teeth or small quantities of teeth unless they have features which by themselves are totally diagnostic. With Premontreia and Scyliorhinus there are a huge variety within the genus and even the species of what the teeth look like. If we had books that showed associated dentitions then identification of individual teeth would be a lot easier. However, we only get to see a few views of a holotype and sometimes of a couple of paratypes of each species which makes identification of individual teeth against those few images very difficult. We also get a couple of paragraph of descriptions. However the descriptions rarely say that you need these 7 features for the tooth to be the species or if the tooth has any of the following features it is definitely not the species. Building dentitions to see how individual teeth might fit in definitely helps to see patterns of what teeth belong and which are something different. But is the something different just age or gender or individual or pathological? The more and more teeth that I look at the more and more that I realize how difficult it is to correctly identify an individual tooth to a specific species. With a lot of my teeth, I take my best shot at an id and don't let the id get to me.

Marco Sr.

[Sélacien34]

"Any day that you can fossil hunt is a great day!!!" : that's so true !

I'm surely not rather good in english to talk clearly and to understand 100% about your explanations and your subtilities, shame ! But it's clear that what i said wasn't correct because what you said is what i said : i can't be sure about the genus or the species here. I did not exactly knew the current level of knowledge about these species. So there are still no books, no set type dentition and therefore no certainty about those teeth. That's what i need to know, thank you very much.

i have taken a look about the dentition of the actual genus and species of galeus and scyliorhinus and it's clear that only a very trained eye can differenciate all those teeth. It's not my case by now !

Edited July 11, 2013 by Sélacien34

[Sélacien34]

The more micro teeth that I collect, and especially the more micro teeth that I collect from a specific site convinces me that a lot of the teeth that I thought were a different genus or species were just positional or individual variations or age variations or gender variations etc.

Did you find teeth like mine in USA ? I mean teeth which looks like the same as mine ?

Edited July 11, 2013 by Sélacien34

[MarcoSr]

I don't search typically for a lot of Miocene micros. I typically search for micros from the Cretaceous, Paleocene and Eocene. Some of your teeth do look similar to teeth that I see from the family Scyliorhinidae in the US like Premontreia degremonti which is similar to your tooth 1. However teeth like tooth 4 are not familiar to me because of the way the base of the crown overhangs the root with the lack of any cusplets. So your teeth are definitely interesting and your pictures show them well. You really do need to get the very well trained eyes of an expert like you said in one of your museums to help you.

Marco Sr.

[Sélacien34]

Very nice and interesting answer, thank you very much Marco. That's true that P. degremonti from Eocene looks like P. distans from miocene. I will have to examine thousand teeth to become such an expert and i'm already rather old . That's why i ask questions, trying to win some time !