upper Turonian/possibly lowermost Coniacian

Texas

A gorgeous representative of a rare species for me - most likely derived from Eagle Ford but Atco is found nearby so not ruling out the possibility!

Turonian (Eagle Ford fm)

Texas

Dumbfounded that it's happened again, and happy it did . Hopefully there's another skeleton behind hiding close by. I suspect this animal is juvenile, with no comment yet on the specific ID. Decided against taking the prep further until I can get the specimen to SMU. The teeth have an interesting preservation that makes them particularly fragile, and this specimen may be important. 

lower middle Turonian

Texas

Turonian

Texas

This is only the second P. decurrens tooth I've found, and the first I've seen in two years. Giant P. decurrens seem to be a feature of the English chalks, and I've yet to see a large one from here in Texas. This is a first for me, and one of my proudest isolated gravel finds.

Upper Turonian

Texas

C. woolgari and P. hyatti both occur in the upper Turonian, as index fossils, but can be difficult to differentiate.

Likely Turonian

Texas

A massive P. marginalis tooth found in float. This is my largest Ptychodus tooth find to date. Though badly worn and found in float, odds are overwhelmingly in favor of Turonian (as opposed to cenomanian) age for this specimen.

Middle Turonian

Texas

ID'd by Cretaceous shark researcher Shawn Hamm - honestly unsure how he narrowed it down but I'll trust his ID

Turonian

Texas

Textbook P. mammilaris tooth, medial file.

Turonian (middle)

Texas

Coniasaur tooth found in middle Turonian strata. One of two elements of coniasaurs I've seen from Turonian strata so far (the other being a vert)

Turonian

Texas

Differentiating S. raphiodon and S.texanus is tricky, and in the cases of lateral teeth like this, it gets trickier, as S. texanus has variable laterals that share characteristics generally associated with S. raphiodon, such as weakly striated blades.

According to Becker et. al in the 2003 paper "Chondrichthyans from the Lower Ferron Sandstone Member of the Mancos Shale (Upper Cretaceous: Middle Turonian) of Emery and Carbon Counties, Utah, USA",  S.raphiodon can be distinguished from the later occurring S. texanus by its smaller size, less pronounced vertical striations, and its tendency to bear cusplets on anterior teeth. This barely helps eliminate options when no anterior teeth are present in your sample. So, concerning lateral teeth, one must rely on age.

Becker et. al continue their analysis of Scapanorhynchus with the following:

"According to Niedzwiedzki and Kalina (2003), S. raphiodon has a chronologic range of Cenomanian-Coniacian and may represent the predecessor of the lineage that later became S. texanus, which is known from the Campanian-Maastrichtian (Case and Schwimmer, 1988; Welton and Farish, 1993)"

They confirm this by citing several papers reporting S. raphiodon within the above chronologic range:

"Extensive literature exists on S. raphiodon, and the species is known from an associated dentition from the Niobrara Chalk of western Kansas (Hamm and Shimada, 2002). Turonian specimens of S. raphiodon in North America have been previously identified from the Codell Sandstone of Colorado (Edwards, 1976), Tres Hermanos Formation of New Mexico (Wolberg, 1985), Blue Hill Shale of eastern Nebraska (Kirk- land, 1989), upper Eagle Ford Group of Texas (Welton and Farish, 1993), Greenhorn Formation and Cariile Shale of Arizona, South Dakota and Wyoming (Williamson et al., 1993; Cicimurri, 2001, 2004), and the Semilla Sandstone Member of the Cariile Shale of central New Mexico (Johnson and Lucas, 2003). From the Straight Cliffs Formation of the Kaiparowits Plateau in south-central Utah, S. raphiodon is known from the Turonian Tibbet Canyon Member, and the genus is reported from the Coniacian-Santonian John Henry Member (Eaton et al., 1999)"

Thus, this confirms pretty strongly for me that despite the overlapping morphology, a middle turonian specimen such as this almost without a doubt represents S. raphiodon.