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fossilsonwheels
35 minutes ago, isurus90064 said:

... and the really crappy ones ...

 

Cretodus semiplicatus

 

~100 - 94 Ma

Late Cretaceous - Cenomanian

"Amon Carter Field"

Woodbine Formation

Tarrant County, TX

 

IMG_9854.jpg.5ca7803e0d80eefd6016a1e1d90addfb.jpg

Crappy is a relative term lol They are still cool from where I am sitting because they are from a cool shark. Most of our collection is less than perfect stuff and the kids we educate think they are cool so I say awesome teeth :) 

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fossilsonwheels
37 minutes ago, isurus90064 said:

... to get to this one ...

 

Cretodus semiplicatus

 

~100 - 94 Ma

Late Cretaceous - Cenomanian

"Amon Carter Field"

Woodbine Formation

Tarrant County, TX

 

IMG_9852.jpg.f8d5ae794e2a8db08aebb1d4b1ae1437.jpgIMG_9853.jpg.6419f6a47d76674c15b294a92a7ae92e.jpg

Outstanding specimen. I can see where this is a bit better than the other ones lol 

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fossilsonwheels

The entire Fossils on Wheels Cretodus collection lol 

 

All are C. crassidens and all from a Texas. 

The largest one is just under 1”. 

 

One on the left 

Kamp Ranch

 

Other two are

Post Oak Creek

 

3BAC973D-3816-4962-991D-72ACF8BBE4C7.jpeg

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fossilsonwheels
5 hours ago, isurus90064 said:

 

Thank you! In case you're interested, Bobby Boessenecker from the forum here has written a couple of papers on P. thomasi:

 

"A Reevaluation of the Morphology, Paleoecology, and Phylogenetic Relationships of the Enigmatic Walrus Pelagiarctos"

 

as well as:

 

"Enamel ultrastructure of fossil and modern pinnipeds: evaluating hypotheses of feeding adaptations in the extinct walrus Pelagiarctos"

 

Instead of posting links here (which will invariably stop working at some point or will not work because you may have to log in somewhere), it's easy to start an account on researchgate.net for example and find the free downloads of those texts. Let me know if that works.

I have read one of those and have read though @Boesse Coastal Paleontologist blog many times. We actually just got our first marine mammal and shark education program booked so I will be studying up over the next three weeks for sure. I think I still have an account through researchgate for my regular job. I will have to check. Thanks again for the information and awesome fossil posts.

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isurus90064

Thank you for posting as well and good luck with the class.

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fossilselachian

A rather uncommon example of Paraisurus

C4E813D7-ADA3-4ACD-B3AA-36DACFF4D0DA.jpeg

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isurus90064

@fossilselachian Fantastic example of Paraisurus, large too! Looks like wrinkles on the shoulders?!

 

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isurus90064

Fairly visible fine wrinkles on a Cretox shoulder ..

 

Cretoxyrhina mantelli

 

~1.31" - 3.33cm

 

~87 - 82 Ma

Upper Cretaceous

Smoky Hill Chalk Member

Niobrara Chalk Formation

Logan County, KS

 

IMG_9843.jpg.c2aebf1d4a5dc165c09e1f6eaaa47493.jpgIMG_9844.jpg.4072d1a88c76d39c7c794fe2da219289.jpgIMG_9809.jpg.5863afa437124ac002952d94fb2e430f.jpgIMG_9839.jpg.d746dffd7642dff2b0ceadbb4d958945.jpg

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fossilsonwheels
On 9/10/2019 at 6:32 PM, fossilselachian said:

A rather uncommon example of Paraisurus

C4E813D7-ADA3-4ACD-B3AA-36DACFF4D0DA.jpeg

Beautiful tooth !!

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isurus90064

Here's a matrix piece with a number of teeth of various species, with a relatively large number of Squalicorax falcatus teeth. The large tooth is Cretoxyrhina mantelli and is about 1.1" - 2.79cm.

 

I count 20 visible teeth in the matrix (not counting micros), at least 16 of which are Squalicorax.

 

~92 - 90 Ma

Upper Cretaceous - Turonian

Kamp Ranch Formation

Eagle Ford Group

Dallas County, TX

(edge of Dallas County, close to Johnson County)

 

EagleFord-Dawson2.jpg.76d5d03df705267dbe640774fe9e1a38.jpg

Stratigraphic nomenclature for Cretaceous outcrops in Texas by William C. Dawson, 2000.

 

 

IMG_9886.thumb.jpg.a3514cb7e955dbb7c09510630dd2f5c7.jpgIMG_9889.thumb.jpg.2f7474c2f2300424b6584e0d8d8cda90.jpgIMG_9885.jpg.fee5aca401b348f062918f4b2889d235.jpgIMG_9884.jpg.e2c6010c5a18c92ab240f64b4dd361b1.jpg

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Woopaul5
On 9/12/2019 at 11:46 AM, isurus90064 said:

Here's a matrix piece with a number of teeth of various species, with a relatively large number of Squalicorax falcatus teeth. The large tooth is Cretoxyrhina mantelli and is about 1.1" - 2.79cm.

 

I count 20 visible teeth in the matrix (not counting micros), at least 16 of which are Squalicorax.

 

~92 - 90 Ma

Upper Cretaceous - Turonian

Kamp Ranch Formation

Eagle Ford Group

Dallas County, TX

(edge of Dallas County, close to Johnson County)

 

EagleFord-Dawson2.jpg.76d5d03df705267dbe640774fe9e1a38.jpg

Stratigraphic nomenclature for Cretaceous outcrops in Texas by William C. Dawson, 2000.

 

 

IMG_9886.thumb.jpg.a3514cb7e955dbb7c09510630dd2f5c7.jpgIMG_9889.thumb.jpg.2f7474c2f2300424b6584e0d8d8cda90.jpgIMG_9885.jpg.fee5aca401b348f062918f4b2889d235.jpgIMG_9884.jpg.e2c6010c5a18c92ab240f64b4dd361b1.jpg

 

One would think if these are all associated that the cretoxyrhina was responsible for the death of the Squalicorax and the micros are just scavengers leaving teeth behind 

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Woopaul5

Squalicorax Lindstomi (Kaupi)

Navasink Fm

Monmouth Co, NJ

 

this tooth is special to me as it was my first Squalicorax tooth I’ve ever found. The fact it has majority of its root lobes makes it slightly rarer than the majority of what I collected in NJ.

4C1ED3D5-E6C3-43F6-992F-C000A79CDB0A.jpeg

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isurus90064
16 minutes ago, Woopaul5 said:

 

One would think if these are all associated that the cretoxyrhina was responsible for the death of the Squalicorax and the micros are just scavengers leaving teeth behind 

 

I like your interpretation, especially because it's entirely possible.

 

Very nice Squalicorax!! from that location.

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Woopaul5

Squalicorax Lindstromi (Kaupi)

Navisink Fm

Monmouth Co, NJ

7CF06D28-267E-424D-8C28-32761412BEC8.jpeg

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Woopaul5

Squalicorax Pristodonus

Navisink Fm

Monmouth Co, NJ

 

 

01CBBCAB-A44A-4727-B278-7DA0FADDAC29.jpeg

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Woopaul5

Arcaeolamna Kopigenisis 

Navisink Fm

Monmouth Co, NJ

7EA0007B-4DDD-44BF-A182-05D6EBC163D7.jpeg

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Woopaul5

Otodus Megalodon

Round Mountain Silt

Kern Co, CA

 

Finally sized it to where I could load this lingual/labial side. One of my favorites in the collection

766222FC-6C71-41F2-B979-1FEF78ACB18D.jpeg

984E5CE7-58BD-4C76-A8D8-0E4B452A1657.jpeg

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Woopaul5

Notorynchus Cepedianus

Pamunkey River, VA

EE035162-B608-420D-82D1-E706DB9CB18C.jpeg

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Woopaul5

O. Angustidens 

Chandler Bridge Fm

Summerville, SC

 

4”+

8A6FC98F-AA00-4475-B01C-039A7CDBC684.jpeg

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Woopaul5

Slightly uncommon I’d say 

 

Somniosis Microcephalus 

Antwerp Sands, Belgium

 

9060C6DE-6D9D-4A61-B251-7CE3F18D89D0.jpeg

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isurus90064

@Woopaul5 Absolutely fantastic meg from STH!!! Thanks for adding the labial side, the light is showing that tooth much better than before. And then that stunner from Summerville, very very nice!!! Beautiful post, thanks! The Somniosus from Belgium and the Notorynchus are quite the beauties as well.

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isurus90064

Had some extra time and just wanted to add a series of garden variety Paleocarcharodon teeth. Some of the past postings that seemed to have generated the most interest were the ones focused on the transition of non-serrated to serrated Paleocarcharodon (including on this thread). In some ways the evolutionary path of this shark still seems to suffer from a little less clarity than some of the other popular macro sharks.

 

With regards to Paleocarcharodon, there also hasn't been much in terms of additional literature beyond what the general audience here has already been exposed to.

 

Here is in summary both generic and specific assignments over time for Paleocarcharodon:

 

1899 Carcharodon orientalis n. sp. - Sinzow. LXXVII. p. 101, pI. IV, figs. 35-37.
1919 Carcharodon landanensis - Leriche, CLXIX, p. 480 (name mentioned in text), pI. XXI, fig.?
1920 Carcharodon landanensis n. sp. - Leriche, VIII, p. 84, fig. 6.
1923 Carcharodon landanensis LERICHE - Bequaert, XXXIII, I, p. 22.
1927 Carcharodon landanensis LERICHE - Leriche, III, p. 60.
1943 Carcharodon landanensis LERICHE - Dartevelle & Casier, III, II, p. A/144- A/145, and A/302-A/303, pI. XXVI, fig. 14 (non-serrated); XXVIII, figs. 4-7 (non 9); and XI, figs. 1-6.
1952 Carcharodon landanellsis LERICHE - Arambourg, p. 118-120, pI. XXI, figs. 7-8.
1960 Palaeocarcharodon landanensis (LERICHE) - Casier, III, n, p. B13-B17, pI. 1, figs. 4-5.
1973 Carcharodon landanensis LERICHE - Case, p. 30, fig. 105.
1987 Palaeocarcharodon orientalis (SINZOW) - Cappetta, 3B, p. 101-102, fig. 89 A-C.

 

Over the past 20 years Paleocarcharodon teeth from Morocco have gone from 'rare' to 'common' and if you've ever purchased any at shows like the Tucson fossil show that far back, you'd know that the price for Moroccan Paleo's has dropped considerably.

 

I also wanted to give it some geological context. Regarding accurate stratigraphic data, when buying fossils from online dealers or dealers from fossil shows, no information related to stratigraphy is accurate. I've bought a number of Paleocarcharodon from dealers who's inventory comes from the Ouled Abdoun Basin (lets call it OAB; sometimes listed as Oulad Abdoun). Not that that is of any help considering the OAB covers more than 9,000 square km/3500 square miles. The other basins that produce fossils from the Maastrichtian - Eocene sequence are Ganntour, Meskala, Souss, and Oued Eddahab basins.

 

Fig. 1 is the outline of the phosphate deposits from that age range. Fig. 2 is are the geological formation with a legend. The dark brown ribbon of phosphatic deposits cover both the Paleocene and lower Eocene (eiPh). As you can see, Paleocene deposits are all over the map, although area wise it is much smaller than the middle and late Eocene layers.

 

1-s2.0-S1342937X13001238-gr1.jpg.dd3bcb78720029de05640c96cb122dfd.jpg

Fig. 1

 

OAB_01_grology.thumb.jpg.b2113532e63a3fce935d5c9a9ef712cf.jpg

Fig. 2

 

5d826a994ca47_GologieDuMaroc1000000_geojamal_Legend.jpg.e1c79b923dec9f61d08b126c6fac5e79.jpg

 

The idea was to then find the exact area on Google Earth Pro, where you can clearly see all the mining operations (if you actually use Google Earth you can get a much better resolution image: fig.3). I then painted out anything that is a non-mine, co-registered on 3 points, then multiply that onto the geological map. They line up quite nicely :-). You can then see that only a fraction of the phosphatic deposits have been mined so far (fig. 4 red overlay).

 

OAB_02_sat.thumb.jpg.2ccdf4fd5521d215e5ab58dd261fa7d2.jpg

Fig. 3 (Google Earth Pro - 2018)

 

OAB_composite.thumb.jpg.481b92aee9123bfe7abfa570a5c5f0de.jpg

Fig. 4 (Carte Geologique du Maroc - 1/1,000,000 scale)

 

One more thing .. this last image is a coarse/low resolution cross section of the OAB lithology:

 

1-s2.0-S1342937X13001238-gr2.thumb.jpg.4be4835303135ecd941bd770d60abafb.jpg

 

One more comment, the geology of the phosphatic basins is very well known. There are countless reports on what the geology in the area looks like exactly that go into excruciating detail. With regards to the lack of information that comes along with the fossils, the problem is clearly on the collecting "pipeline" if you will.

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isurus90064

The paper that includes the 1960 Paleocarcharodon Landanensis assignment I had to take pictures of because it is some old scientific literature format (28 x 37cm).

 

1960_Paleocarcharodon_landanensis.pdf

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isurus90064

Last, I'm hoping someone can add the paper below as a scan or photo from Cappetta's "Chondrichthyes II ......" p. 101-102 and fig. 89 A-C. Mine is still in a box somewhere as a result of us moving last year.

 

1987 Palaeocarcharodon orientalis (SINZOW) - Cappetta, 3B, p. 101-102, fig. 89 A-C.

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