Thrilling Threshers!

[HoppeHunting]

The genus Alopias, commonly known as the Thresher Shark, has been around for millions of years. These sharks use their abnormally long, whip-like caudal fin to stun their prey. This fin can grow to become more than half the length of shark's entire body. It is a strange and fascinating creature, and has been one of my favorite sharks ever since I was a little boy. Today, we fossil hunters can find the fossilized teeth of Thresher Sharks. They are typically rather small, and relatively uncommon. They look really cool in my opinion, and they're among my favorite types of shark teeth that are on the smaller side. 

 

So for this thread, SHOW US YOUR THRESHERS!  I'll start by posting a neat little ring I made with my best Threshers so far. I'm excited to see what you all have found. Like I said, most of these teeth are pretty small, but I do understand that there's a species of Giant Thresher that can apparently be found at Calvert Cliffs and elsewhere. I've seen a few pictures, but never found one. Let's see what you all got!

[SailingAlongToo]

Here is my serrated Alopias grandis.

 

 

[Gizmo]

 One I found at Calvert Cliffs. - 

 

 

[Miocene_Mason]

I LOVE threshers! I have found few (a measly Alopias latidens) but I have bought a few: 

first picture my rarest, a double cusped trigonotodus (Alopias) alteri from Summerville. The sellers, @Sharks of SC, picture

[Miocene_Mason]

Alopias (Trigonotodus) grandis from South Carolina coast (the online seller had it labeled as a Megalodon)

[Miocene_Mason]

My brownies Alopias latidens from some micro I collected

[Miocene_Mason]

and Lastly a summerville Alopias (Trigonotodus) grandis also from @Sharks of SC

[Miocene_Mason]

And one more thing I’d like to add, the giant threshers (Trigonotodus, grandis, alteri, and otherwise) most likely lacked a “thresher tail”. Also, Bretton Kent says a genus called Paranomotodon (a Thresher he says) exists in Maryland’s Cretaceous. I’ve yet to see one of these.

[HoppeHunting]

13 hours ago, WhodamanHD said:

Maryland’s Cretaceous

Maryland has Cretaceous exposures? How come I've never heard of that? That's awesome!

[Miocene_Mason]

42 minutes ago, HoppeHunting said:

Maryland has Cretaceous exposures? How come I've never heard of that? That's awesome!

The best east of the Mississippi, the Marine ones are Late Cretaceous but most sites have either been destroyed, put off limits, or depleted. The mid-Cretaceous sites are terrestrial, but produce dinosaur remains and the best footprints in the world frequently in some places (mostly known only to people like Ray Stanford, though dinosaur park has bones and  is open to the public as long as you give them anything you find). 

[HoppeHunting]

1 hour ago, WhodamanHD said:

Marine ones are Late Cretaceous but most sites have either been destroyed, put off limits, or depleted.

Do you know if there are any that are still accessible? Hunting a dinosaur-aged site would be really cool!

[Miocene_Mason]

2 hours ago, HoppeHunting said:

Do you know if there are any that are still accessible? Hunting a dinosaur-aged site would be really cool!

I don’t, However I know a site from the Mid-Cretaceous with a lot of iron, probably few-no bones there but who knows? I’ll tell you where if you want.

[HoppeHunting]

2 hours ago, WhodamanHD said:

Mid-Cretaceous. I’ll tell you where if you want.

No it’s fine. I’d rather hunt a marine site from the Late Cretaceous. But thanks anyway! I have heard about the dino footprints that can be found in parts of VA and Maryland. Sounds pretty cool and might be something worth trying at some point. Have you done much terrestrial hunting?

[Miocene_Mason]

1 hour ago, HoppeHunting said:

No it’s fine. I’d rather hunt a marine site from the Late Cretaceous. But thanks anyway! I have heard about the dino footprints that can be found in parts of VA and Maryland. Sounds pretty cool and might be something worth trying at some point. Have you done much terrestrial hunting?

I know some late Cretaceous sites exist on the banks of the Severn river, I don’t know how to get to them though. The two main footprint producing formations are the Triassic Gettysburg shale which is mostly north Frederick county (which I have searched for a nice site in to no avail, except some rain drops and some worm burrows) and the Potomac group of PG county. I was lucky enough to see the big plate (which had thousands of dinosaur, croc, pterosaur, and mammal tracks) while it was being excavated at NASA green belt. Stanford says he finds them in streams in college park, but of course will not reveal where. I do hunt on land if that’s what you mean, western Maryland (Devonian, soon Carboniferous), West Virginia (Devonian), Pennsylvania (Cambrian, Devonian, Carboniferous) and the trilobite ridge of NJ.

[EMP]

On ‎3‎/‎3‎/‎2018 at 9:42 PM, WhodamanHD said:

I know some late Cretaceous sites exist on the banks of the Severn river, I don’t know how to get to them though. The two main footprint producing formations are the Triassic Gettysburg shale which is mostly north Frederick county (which I have searched for a nice site in to no avail, except some rain drops and some worm burrows) and the Potomac group of PG county. I was lucky enough to see the big plate (which had thousands of dinosaur, croc, pterosaur, and mammal tracks) while it was being excavated at NASA green belt. Stanford says he finds them in streams in college park, but of course will not reveal where. I do hunt on land if that’s what you mean, western Maryland (Devonian, soon Carboniferous), West Virginia (Devonian), Pennsylvania (Cambrian, Devonian, Carboniferous) and the trilobite ridge of NJ.

 

I've collected in some of those streams near College Park, quite recently as a matter of fact. I've also hunted at Dinosaur Park a it. Sure beats driving all the way out to the Pocono rocks, and the possibility of dinosaurs is also pretty cool! 

 

From my experience the Potomac Group rocks near DC are more fossiliferous than the Newark Group ones near Emmitsburg. The best formation for footprints is the Patuxent Formation (the one I hunted in), while the Arundel Clay tends to be best for actual bones and teeth. Both formations contain a decent floral assemblage, but overall I think the Arundel Clay is a tad more biodiverse, likely owing to it's lacustrine depositional environment. 

 

You'd be surprised how much is in those streams. I went there expecting a couple of plant stems and not much else, but I ended up having trouble taking all the rocks I wanted to keep! Lots of plant fragments and some wood pieces, but I also found a gastropod shell imprint (I don't think those are too common from these rocks), and a possible dinosaur footprint! Considering I spent less than an hour on actual looking it was pretty good. 

 

The only issue is that trash is everywhere along those streams that you have to keep your eyes peeled. Broken glass, sharp can edges, wire, just general hazards of urban collecting. Also, the area isn't that great, and it's not too safe to stay long past dark I'd think, especially as a, shall we say, outsider. There has been an uptick in crime too. Make sure your car's locked tight and don't leave any valuables visible (I'd even advice against bringing anything beyond bare essentials, to be honest). 

 

Some of the areas can be pretty overgrown during the summer, so bare that in mind too. But if you take the proper precautions and put in the necessary effort I think those streams could yield a lot. 

 

As for @HoppeHunting, I've hunted extensively in Maryland terrestrial units. For such a small state, Maryland really punches above it's weight class in regards to fossil hunting. We have everything ranging from the late Ordovician Juniata Formation to the deposits around the Chesapeake Bay for land fossils. Personally I've mostly collected in the early Mississippian Pocono Group and the early Cretaceous Potomac Group, but I've also hunted in the late Devonian Hampshire Formation, the late Triassic Gettysburg Shale, and one time visited the Pleistocene Columbia Group (never found anything but one shell, so I guess it perhaps doesn't count much). I won't give exact sites, but I'll gladly help in other ways. 

 

There's always places around Bowie or Oxon Hill for Cretaceous shark teeth, but I'd, uh, advice against visiting Oxon Hill as locals would likely agree with. 

[Miocene_Mason]

14 minutes ago, EMP said:

Juniata Formation

Where do you keep finding all these new formations?! Another one I didn’t know existed, shows I still need to cover a lot more land! 

I’ll have to get to some of those Cretaceous places at some point, but I think I’ll try the Carboniferous first. I’ll pick out a nice weekend to go west and drive around and maybe hike Near some rivers. This reminds me, I have a question I was going to ask you via PM, not asking for a site or anything, just info.

[EMP]

1 minute ago, WhodamanHD said:

Where do you keep finding all these new formations?! Another one I didn’t know existed, shows I still need to cover a lot more land! 

I’ll have to get to some of those Cretaceous places at some point, but I think I’ll try the Carboniferous first. I’ll pick out a nice weekend to go west and drive around and maybe hike Near some rivers. This reminds me, I have a question I was going to ask you via PM, not asking for a site or anything, just info.

 

Haha, the Juniata is a very minor formation in Maryland. It's only exposed really at the Wind Gap near Cumberland (there's a spectacular exposure along the CSX rail lines nearby). It doesn't have very many fossils, the only ones that have been found were from Pennsylvania and they were limited to faint traces of millipede like creatures and possible plants. 

 

Carboniferous is a good one in MD. I'd definitely suggest the Georges Creek region. I can PM you a couple of exposures I've seen. I can't guarantee any good finds from them, but eventually something would have to produce fossils, right? 

[Miocene_Mason]

59 minutes ago, EMP said:

 

Haha, the Juniata is a very minor formation in Maryland. It's only exposed really at the Wind Gap near Cumberland (there's a spectacular exposure along the CSX rail lines nearby). It doesn't have very many fossils, the only ones that have been found were from Pennsylvania and they were limited to faint traces of millipede like creatures and possible plants. 

 

Carboniferous is a good one in MD. I'd definitely suggest the Georges Creek region. I can PM you a couple of exposures I've seen. I can't guarantee any good finds from them, but eventually something would have to produce fossils, right? 

Ordovician plants, those are some old plants indeed! Learn something (or many things) new every day! Grammar didn’t quite work out there....

 

Hope springs eternal! I’d love to visit some known exposures for sure, If there are no fossils, at least some fresh air, eh? Thanks!

[Fossil-Hound]

@HoppeHunting yes they are gorgeous. Here's one from Calvert Cliffs. Baby thresher. 

[non-remanié]

On 3/18/2018 at 9:06 PM, EMP said:

 

There's always places around Bowie or Oxon Hill for Cretaceous shark teeth, but I'd, uh, advice against visiting Oxon Hill as locals would likely agree with. 

 

Why??   Because its a working class  neighborhood??   Oxon Hill is 30% above the median household income level for the entire US btw. 

 

 

[Miocene_Mason]

8 minutes ago, non-remanié said:

 

Why??   Because its a working class  neighborhood??   Oxon Hill is 30% above the median household income level for the entire US btw.    I know you're  young and perhaps a bit shelteted, but I think I know what you were implying and I think you can do better.    

 

 

How old are those stats? The situation in Prince George county is complicated, having more to do with its unique position than its income. Also I think I’ve heard stories about Bowie, they do not take kindly to fossil hunters. I’ve heard of armed guards patrolling, perhaps that’s just rumor.

[non-remanié]

The stats are recent .  The old Bowie site is a different story due to the military building of some sort right next to the fossil site.   

[Miocene_Mason]

@Fossil-Hound That is super cool! Never seen nor heard of a juvenile Thresher fossil, but I guess we all gotta start somewhere

[Al Dente]

On 3/18/2018 at 9:06 PM, EMP said:

 

There's always places around Bowie or Oxon Hill for Cretaceous shark teeth, but I'd, uh, advice against visiting Oxon Hill as locals would likely agree with.

I lived in Oxon Hill in the early 1970s for three years. We were lucky enough to have a house along the Potomac. I was in grade school and some of the first fossils I ever collected came from there. It was a great place to live, my friends and I spent many hours wandering along the river. A few years ago I went back to our old house and found they had filled in much of the river behind the house and built the National Harbor there. There is now a large wall separating my old neighborhood from the National Harbor. No more access to the river from my old house.

[eddie]

Here are my "giant threshers."   I have some pretty nice smaller Alopias species, but need to get some decent pics.