Thursday, November 16, 2023

Recent finds from lowcountry waterways - early October 2023

The past six weeks have been quite busy - I was swamped with work before SVP (Society of Vertebrate Paleontology), then I had the conference, and then I caught covid for a second time - fortunately, no cardiovascular issues, no long covid, and paxlovid is a helluva miracle drug. Since SVP, Charleston Fossil Adventures has transitioned to our off-season tour spot - but that'll be covered in the next post. October - even with SVP and covid - was so fossil-rich that I'm doing two different posts!

If you want to have a guided tour and be shown how to find (and keep) all sorts of fossils like this, check out available bookings on https://www.chsfossiladventures.com/.

A nice shark vertebra - probably from a small lamniform shark (mackerel shark).

Marsh periwinkles (Littoraria irrorata) may be aquatic snails but they like being *just* above the water. They often climb out of the water and can be found on spartina grass like this at high tide. 

 

A nice example of a tooth of the as-yet-unnamed Oligocene Parotodus - 'false mako' and the lesser megatoothed shark lineage. These are my favorite teeth, and I only find them rarely... two clients found these two days in a row. I photographed this one, Ashby photographed the other.

A lower tooth of Galeocerdo aduncas - easily confused with Physogaleus contortus, to the point where the two were synonymized for a while. Turns out that they can be separated on the basis of compound serrations on the distal part of the tooth.

A nice snaggletooth, Hemipristis serra, sitting in limestone sand.

A very, very small caniniform tooth from a barracuda (Sphyraena).

 
This one puzzled me for a few minutes but Ashby identified it as a partial dentary of a cutlassfish (Trichiurus or Trichiuridae) - kind of fascinating that the teeth appear to break off at the root and new teeth just grow on top of the old ones! But then again, there's a lot about teleosts I don't understand.

 
We see bottlenose dolphins (Tursiops erebennus) all the time on our river and harbor tours - 3 out 5 river tours, and 4 out of 5 harbor tours. This day we saw a whole pod, but only got good photos of this individual - I was filming when multiple dolphins came up. I took this with a CELL PHONE.

 
On one of our accidentally-longer days we decided to head a mile further down the river and check out a slightly larger manmade island with some kind of phosphate spoil or artificial fill on the geologic map - and it turned out to be completely non-fossiliferous. Some of the most beautiful clean white sugary sand in the whole state ended up making up this island - but not a single tooth. Surprisingly clear water - we spent an hour and a half doing some "real Tom Sawyer type shit". It was also just absolutely beautiful.

 
A nice example of a dolphin periotic bone with the ventral surface of the pars cochlearis busted off so that you can see the entire cochlea (aside from the innermost turn, which is missing). This one is probably a bottlenose dolphin (Tursiops sp.) and is likely to be a Pliocene specimen.

 
A large kitefin sawfish rostral spine, Anoxypristis.

 
Snaggletooth specimens don't get much larger than this out on the river - after all they're probably Oligocene, and the species Hemipristis serra underwent a gradual increase in maximum size from the Oligocene through to the Pliocene/Pleistocene.

 
I had one morning tour on Folly beach in early October - no fossil photos, but I did have a rather glorious view just after sunrise.


One of our little unidentified coprolites: these are typically flat and have a very ropy pattern to them - almost like filling up an ant farm with soft-serve ice cream. I imagine these are from some kind of fish.

 
A tympanic bulla of an Oligocene dolphin spotted amongst the gravel - a waipatiid dolphin.

 
A good comparison of a lower tooth of the extinct tiger shark Galeocerdo aduncas (left) versus a tooth of the very similar Physogaleus contortus (right) - note the coarse serrations with finer sub-serrations in on the "heel" (side of the tooth behind the large notch defining the main cusp) of the Galeocerdo tooth and the simple, smaller serrations on the Physogaleus tooth.
 
 
At one of our more secret locations we've been finding some unusual teeth, including over 20 specimens of the sawshark Pristiophorus - sawsharks (Pristiophoriformes) are true sharks (Neoselachii) and within the clade Squalomorphii, along with angel sharks (Squatiniformes), dog sharks (Squaliformes), cow sharks (Hexanchiformes). These teeth (rostral spines, rather) differ from those of Pristidae (sawfish) in having enameloid and a root; the spines of sawfish are all osteodentine. Here's a Pristiophorus tooth and the much larger tooth of a kitefin sawfish, Anoxypristis, found moments apart at the same Oligocene dredge spoil.
 
 
A small tooth of a baby snaggletooth shark, Hemipristis serra.

 
A rather colorful and grumpy mud crab, Panopeus herbstii. 

 
A small megatoothed shark specimen, probably Carcharocles angustidens. Tip top shape!

 
Several marsh periwinkles (Littoraria irrorata) hitch-hiked back into the boat and ended up a few miles down the river from where they normally lived. Hopefully they're too dim to realize it. It's still all marsh, anyway.
 
 
An ?Oligocene specimen of a diodontid, probably the burrfish Chilomycterus - this beak + toothplate is very, very small, less than 1 cm wide.
 

 A sheepshead (Archosargus) left behind by a fisherman. I think it had been gutted. these fish have unusually human-like teeth in the front... and it's all downhill from there once you open the mouth up.
 

And lastly, a cute little fiddler crab (Uca pugnax) I managed to get a photo of. You practically have to run these guys down and sprint at them and snap off a few shots while their little arthropod brains are struggling to make decisions.

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