QUENSTEDTOCERAS WITH PATHOLOGY

What you are seeing here is a protuberance extruding from the venter of Quenstedtoceras cf. leachi (Sowerby). It is a pathology in the shell from hosting immature bivalves that shared the seas with these Middle Jurassic, Upper Callovian, Lamberti zone fauna from the Volga River basin. The collecting site is the now inactive Dubki commercial clay quarry and brickyard near Saratov, Russia. 

The site has produced thousands of ammonite specimens. A good 1,100 of those ended up at the Black Hills Institute of Geological Research in Hill City, South Dakota. 

Roughly 1,000 of those are Quenstedtoceras (Lamberticeras) lamberti and the other 100 are a mix of other species found in the same zone. These included Eboraciceras, Peltoceras, Kosmoceras, Grossouvria, Proriceras, Cadoceras and Rursiceras. 

What is especially interesting is the volume of specimens — 167 Quenstedtoceras (Lamberticeras) lamberti and 89 other species in the Black Hills collection — with healed predation injuries. It seems Quenstedtoceras (Lamberticeras) lamberti are the most common specimens found here and so not surprisingly the most common species found injured. Of the 1,000, 655 of the Quenstedtoceras (Lamberticeras) lamberti displayed some sort of deformation or growth on the shell or had grown in a tilted manner. 

Again, some of the Q. lamberti had small depressions in the centre likely due to a healed bite and hosting infestations of the immature bivalve Placunopsis and some Ostrea. 

The bivalves thrived on their accommodating hosts and the ammonites carried on, growing their shells right up and over their bivalve guests. This relationship led to some weird and deformities of their shells. They grow in, around, up and over nearly every surface of the shell and seem to have lived out their lives there. It must have gotten a bit unworkable for the ammonites, their shells becoming warped and unevenly weighted. Over time, both the flourishing bivalves and the ammonite shells growing up and over them produced some of the most interesting pathology specimens I have ever seen.    

In the photo here from Emil Black, you can see some of the distorted shapes of Quenstedtoceras sp. Look closely and you see a trochospiral or flattened appearance on one side while they are rounded on the other. 

All of these beauties hail from the Dubki Quarry near Saratov, Russia. The ammonites were collected in marl or clay used in brick making. The clay particles suggest a calm, deep marine environment. One of the lovely features of the preservation here is the amount of pyrite filling and replacement. It looks like these ammonites were buried in an oxygen-deficient environment. 

The ammonites were likely living higher in the water column, well above the oxygen-poor bottom. An isotopic study would be interesting to prove this hypothesis. There's certainly enough of these ammonites that have been recovered to make that possible. It's estimated that over a thousand specimens have been recovered from the site but that number is likely much higher. But these are not complete specimens. We mostly find the phragmocones and partial body chambers. Given the numbers, this may be a site documenting a mass spawning death over several years or generations.

If you fancy a read on all things cephie, consider picking up a copy of Cephalopods Present and Past: New Insights and Fresh Perspectives edited by Neil Landman and Richard Davis. Figure 16.2 is from page 348 of that publication and shows the hosting predation quite well. 

Photos: Courtesy of the deeply awesome Emil Black. These are in his personal collection that I hope to see in person one day. 

It was his sharing of the top photo and the strange anomaly that had me explore more about the fossils from Dubki and the weird and wonderful hosting relationship between ammonites and bivalves. Thank you, my friend!

QUENSTEDTOCERAS WITH PATHOLOGY

What you are seeing here is a protuberance extruding from the venter of Quenstedtoceras cf. leachi (Sowerby). It is a pathology in the shell from hosting immature bivalves that shared the seas with these Middle Jurassic, Upper Callovian, Lamberti zone fauna from the Volga River basin. The collecting site is the now inactive Dubki commercial clay quarry and brickyard near Saratov, Russia. 

The site has produced thousands of ammonite specimens. A good 1,100 of those ended up at the Black Hills Institute of Geological Research in Hill City, South Dakota. 

Roughly 1,000 of those are Quenstedtoceras (Lamberticeras) lamberti and the other 100 are a mix of other species found in the same zone. These included Eboraciceras, Peltoceras, Kosmoceras, Grossouvria, Proriceras, Cadoceras and Rursiceras. 

What is especially interesting is the volume of specimens — 167 Quenstedtoceras (Lamberticeras) lamberti and 89 other species in the Black Hills collection — with healed predation injuries. It seems Quenstedtoceras (Lamberticeras) lamberti are the most common specimens found here and so not surprisingly the most common species found injured. Of the 1,000, 655 of the Quenstedtoceras (Lamberticeras) lamberti displayed some sort of deformation or growth on the shell or had grown in a tilted manner. 

Again, some of the Q. lamberti had small depressions in the centre likely due to a healed bite and hosting infestations of the immature bivalve Placunopsis and some Ostrea. 

The bivalves thrived on their accommodating hosts and the ammonites carried on, growing their shells right up and over their bivalve guests. This relationship led to some weird and deformities of their shells. They grow in, around, up and over nearly every surface of the shell and seem to have lived out their lives there. It must have gotten a bit unworkable for the ammonites, their shells becoming warped and unevenly weighted. Over time, both the flourishing bivalves and the ammonite shells growing up and over them produced some of the most interesting pathology specimens I have ever seen.    

In the photo here from Emil Black, you can see some of the distorted shapes of Quenstedtoceras sp. Look closely and you see a trochospiral or flattened appearance on one side while they are rounded on the other. 

All of these beauties hail from the Dubki Quarry near Saratov, Russia. The ammonites were collected in marl or clay used in brick making. The clay particles suggest a calm, deep marine environment. One of the lovely features of the preservation here is the amount of pyrite filling and replacement. It looks like these ammonites were buried in an oxygen-deficient environment. 

The ammonites were likely living higher in the water column, well above the oxygen-poor bottom. An isotopic study would be interesting to prove this hypothesis. There's certainly enough of these ammonites that have been recovered to make that possible. It's estimated that over a thousand specimens have been recovered from the site but that number is likely much higher. But these are not complete specimens. We mostly find the phragmocones and partial body chambers. Given the numbers, this may be a site documenting a mass spawning death over several years or generations.

If you fancy a read on all things cephie, consider picking up a copy of Cephalopods Present and Past: New Insights and Fresh Perspectives edited by Neil Landman and Richard Davis. Figure 16.2 is from page 348 of that publication and shows the hosting predation quite well. 

Photos: Courtesy of the deeply awesome Emil Black. These are in his personal collection that I hope to see in person one day. 

It was his sharing of the top photo and the strange anomaly that had me explore more about the fossils from Dubki and the weird and wonderful hosting relationship between ammonites and bivalves. Thank you, my friend!

CARNOTAURUS: FLESH-EATING BULL

Carnotaurus sastrei, a genus of large theropod dinosaurs that roamed the southern tip of Argentina, South America during the Late Cretaceous, 72 to 69.9 million years ago. His name means "flesh-eating bull,' and he lives up to it.

This fellow — or at least his robust skull with the short, knobby eyebrow horns and fierce-looking teeth — is on display at the Natural History Museum in Madrid, Spain. For now, he is the only known genus of this species of bipedal predator.

The first specimen of Carnotaurus sastrei was found in Chubut on vast plains between the Andes Mountains and the Atlantic Ocean. A physician, Dr. A'ngel Tailor noticed a large concretion showing some bone fragments. A team led by José F. Bonaparte excavated the find in 1984 as part of a paleontological expedition funded by the Argentine Museum of Natural Sciences.

Sadly, Bonaparte — the Maestro del Mesozoico — passed away the 18th February 20220 at the age of 91. He spent the majority of his career as head of the Vertebrate Palaeontology Division of the Museo Argentino de Ciencias Naturales “Bernardino Rivadavia,” in Buenos Aires. Bonaparte opened up the vertebrate finds of Argentina to the world. He was instrumental in the finding, excavating and naming many iconic dinosaurs — Carnotaurus, Amargasaurus, Abelisaurus, Argentinosaurus, Noasaurus along with the finding of the first fossilised remains of Mesozoic South American mammals. He mentored many palaeontologists who will miss his keen eye and tremendous work ethic — Luis Chiappe, Rodolfo Coria, Agustín Martinelli, Fernando Novas, Jaime Powell, Guillermo Rougier, Leonardo Salgado, Sebastián Apesteguía and many others.

His excavation of Carnotaurus was the first of its kind and he recognized that the skull is quite unusual. Initially, it has a very marine reptile feel — but make no mistake this guy is clearly a terrestrial theropod. He had smallish, underdeveloped arms — teeny by theropod standards. Once you look closer you see his bull-like horns from whence he gets his name — horns that imply battle between rivals for the best meal, sexual partner and to be the one who leads the herd. 

He was covered in leathery skin lined with rows of cone-shaped nodules or bumps. These get larger as they move towards his spine. He had forward-facing eyes, similar to tyrannosaurs like T-rex and smaller theropods like Velociraptor and Troodon — who had better vision even that T-rex — which would have given him the advantage of binocular vision and depth perception. Forward-facing eyes are also quite helpful with nocturnal hunting — think owls and cats — as they take in more light and help with nighttime predation. So perhaps this flesh-eating bull fancied a late-night snack on his menu from time to time.

Species like squirrels, pigeons and crocodiles have eyes on the sides of their heads. They lack the important competitive feature of well-developed depth perception — being able to easily and estimate distance — but perhaps make up for it with a panorama that offers a wider field of view.   

CADOCHAMOUSSETIA SUBPATRUUS

Cadochamoussetia subpatruus (Nikitin 1885)

I have a thing for chunky ammonites and find their inflated shapes very pleasing. 

This lovely chunky macroconch is the female of the species Cadochamoussetia subpatruus (Nikitin 1885). 

She hails from the Middle Jurassic, Lower Callovian, Elatmae zone, Subpatruus subzone in a clay mining quarry near Uzhovka 2, in the Pochinoksky district of Nizhny of the Novgorod region of western Russia. 

This specimen has signs of intravital damage (i.e., damage that did not immediately lead to death) on the edge of her shell. 

We see this type of non-lethal damage recorded on the shells of ammonites and other marine goodies in the fossil record. These telltale bits of evidence for challenges to the species while living are recorded and preserved long before the burial event. We see similar signs of damage on the shells of modern Nautilus. 

These lesions resemble frequently bitten edges. Perhaps damage from predation or the result of bashing up against something solid on the seafloor. There is a wee bit more damage on the mouth of the shell. Where the shell should have stopped growing upon the ammonite reaching puberty, the growth continues for another 5 cm of thinly laminated shell — perhaps signalling physicochemical impact or shortage of resources for the ongoing construction of the usual thickness. This photo is courtesy of the deeply awesome Emil Black.