Shark? Fish?

[geofossil]

When hiking way up in the Rockies I came across a couple chunks of rocks with scales in them. Articulated scales of some type. I'm wondering if they are shark or related or possibly from some other fish. The rocks are either latest Devonian or Earliest Carboniferous. I'm not too keen on collecting 'chunks' up high as it's not all that safe scrambling along knife edges, ridges and so on with extra ballast shifting around in the pack....but couldn't resist a chunk. I've one other specimen of Carboniferous matrix with scales in them but they are inarticulated and the scale surfaces don't have any relief to them. The specimen on the 'chunk' are the blue-black calcium phosphate we find in paleozoic shark teeth but perhaps it is also indicative of a fish. The individual scales are about the same size of those of a garpike

I've surfed the net of modern shark scales (denticles) and can't see anything resembling my specimen other than the scales of a modern whale shark....but that might just be coincidence. The scales of the whale shark vary from eachother but the ones on my specimen are all the same. Perhaps there is a fish with the pattern.

The first photo is 'the chunk' (penny for scale) and the second is a closer up (not too clear). I've included a third image I found on the web of those of a modern whale shark.

I'm just wondering if any of you have collected articulated or isolated shark scales that resemble those on the specimen. I've collected lots of shark teeth in various locations but not scales. Where we find individual shark teeth as in our nearby Cretaceous deposits we never find scales.

Shark or not? Also a question if anyone knows modern sharks. Do the scales vary in shape over the surface of a shark? We have a lot of garpike scales in the Cretaceous but they vary in shape. The scales on my 'chunk' don't have any variance from each other. I assume (maybe wrongly) this indicates a large individual animal. Does a large shark have bigger scales than a small one or just more of them? Any guidance appreciated.

(penny for scale)

This image of whale shark scales has similar patterns on the scale as the specimen BUT...it seems to be the exception among shark scales. Are there also fish scales with similar patterns?

[Mike Owens]

Looks like fish skin/scales to me. I have one specimen for you to compare it to. This is a Cretaceous hunk of fish (has vertebrates running through it) most likely Pachyrhizodus.

[Northern Sharks]

Geo: I also collect modern shark jaws to match with my fossil teeth. I have 1 small skin sample from a Port Jackson shark and there is a difference in the denticles from 1 area of the sample to the next. I may just be wear or how the sample was prepped that made it this way. PJ's apparently have some of the largest denticles of any living species. Your example (awesome looking piece ) seems to be much to big to have been a shark. I gotta get out to the rockies

[geofossil]

Looks like fish skin/scales to me. I have one specimen for you to compare it to. This is a Cretaceous hunk of fish (has vertebrates running through it) most likely Pachyrhizodus.

Your specimen is 'neato'. I'm familiar with some Cretaceous fish scales but wonder if there is something that makes a shark denticle distinct. I suppose there are thousands of fish species and hundreds of sharks so maybe generalizations can't be made. Below is a photo of garpike scales (Lepidosteus) we find in the badlands. Along with Myledaphus bipartitus teeth (a ray), these scales can be quite common. I was north of Jordan, Montana once and along a flat stretch there were thousands. Having said this, I've never found any of these scales articulated and have found no shark denticles in the badlands....just teeth and vertebrae. Also never any articulated Myledaphus jaw/teeth sections or articulated shark sections.

[geofossil]

Geo: I also collect modern shark jaws to match with my fossil teeth. I have 1 small skin sample from a Port Jackson shark and there is a difference in the denticles from 1 area of the sample to the next. I may just be wear or how the sample was prepped that made it this way. PJ's apparently have some of the largest denticles of any living species. Your example (awesome looking piece ) seems to be much to big to have been a shark. I gotta get out to the rockies

It's the 'going up' and more importantly how fast the 'going down' that is as important as getting to the Rockies.

'Many' years ago I used to live in Nova Scotia and helped check the tidal wiers for fish. We used get sharks in the wiers all the time and we just dumped them in the tidal pools in the Bay of Fundy. I can't say I ever paid any attention to them. They were a 'nuisance' and meant 'work'. I can't recall a thing about their teeth or denticles. most were what we called 'dogfish' but every so often some 'biggie' would be caught. You didn't put your hands near their mouths but I don't recall them being dangerous or aggressive. They swam off on their merry way once the tides came back in. It's strange because now I'm a bit of a nature nut and can't imagine not taking more interest in the natural world that was around me.

[ebrocklds]

i feel they would fit in with gars some how. the overall shape and articulation pattern seems to be very similar. the ornate surface is something that could easily be a species modification. although i am not sure how far back gars go. maybe i am just confusing the issue anyways that is my opinion.

brock

[worthy 55]

Could it be ray or shark skin ??? :huh:

[Bill]

Hi Geofossil,

This may help.

http://images.google.co.uk/imgres?imgurl=h...8GB248%26sa%3DN

[Guest Nicholas]

Could it be ray or shark skin ??? :huh:

I was thinking the same thing.

[Guest N.AL.hunter]

I can only add ... WOW! I really think that this is a neat specimen! Please let us know what it is when you get it IDed. Also, please take another closeup like the second picture but in focus. I would love to see this thing more clearly.