New titanosaurian fossils from Allen Formation (late Maastrichtian) of Argentina

[Ben Creisler]

Ben Creisler

bcre...@gmail.com

A new paper:

Flavio Bellardini, Guillermo J. Windholz, Diego A. Pino, Alberto C. Garrido, Rodolfo García & Diego Pol (2026)
Sauropod resilience in the southeastern Neuquén Basin at the end-Cretaceous: new titanosaurian evidence from the Allen Formation (late Maastrichtian) of Patagonia, Argentina
Journal of Vertebrate Paleontology e2728671
doi: https://doi.org/10.1080/02724634.2026.2728671
https://www.tandfonline.com/doi/full/10.1080/02724634.2026.2728671


The Late Cretaceous sauropod fauna of Patagonia shows a high taxonomic diversity and a widespread distribution, including over a third of all known Gondwanan sauropod taxa. However, the Maastrichtian record is still poorly represented, particularly when compared to the sauropod evidence from the Cenomanian or Santonian–Campanian time-lapses. Here, we describe new sauropod specimens from the Allen Formation of the Bajo de Santa Rosa (Patagonia, Argentina), including a single individual (MML-Pv-1031) with disarticulated but associated cranial (one tooth), axial (several dorsal ribs, one caudal vertebra and three hemal arches), and appendicular elements (two sternal plates, two metacarpals, one ischium, and two fibulae). An additional isolated tooth (MML-Pv-1032) was also found in the same site. The strongly procoelic articulation of the caudal vertebra, the dorsoventrally low ischium, the semilunar sternal plates, and the slender, straight fibulae with a prominent lateral trochanter of MML-Pv-1031 resemble the morphological conditions of several titanosaurian taxa. Furthermore, some features of the sternal plates and fibulae of MML-Pv-1031 differ from the four titanosaurian species with overlapping elements from the Allen Formation, Aeolosaurus rionegrinus, Bonatitan, Menucocelsior, and Rocasaurus. This suggests the presence of a fifth sauropod taxon in this formation, although the absence of diagnostic elements prevents the naming of a new species. These new titanosaurian findings provide evidence for the presence of sauropods throughout the middle member of the Allen Formation, which is coeval with climatic and environmental changes over time in northern Patagonia during the Maastrichtian, linked with the ocean transgression at that time.

[Gregory Paul]

i. e. Otodus megalodon, is now the official Maryland state shark! 

An effort earlier this year failed, but they put it in a bigger bill that passed. There is a full size skeleton at the very nice Calvert Marine Museum in the Solomons which is a great visit, and apparently not about to close. 

Back in the 60s my nuclear family would spend a few days each summer at the Willows private beach on the western shore of the Chesapeake Bay, SE of DC. Many fond memories. Including when a screaming F-101 Voodoo supersonic interceptor flew parallel to the beach at about 500 ft, third of a mile or less out, and maybe 400 mph, like at the end of the Russians Are Coming, The Russians Are Coming.

Cottage we stayed in was owned by family friend "Tip" Tipton, who was big on barbecue -- he is still mentioned in the locations website. As those little cottages are long ago replaced. 

The nice beach was 50-70 ft across depending on tide level. Cargo ships heading north and south to and from Baltimore. Immediately to the north was/is a stretch of the Calvert Cliffs Formation. Me and my older brother or later friend would walk along below those cliffs with the warm waves lapping at their bases. That is now discouraged or banned, the sediments are soft and often collapse, killed a little girl I think in the 1990s. Then it was the 60s when we kids roamed the landscape. etc.   

Those collapsing cliffs dumped vast quantities of Miocene sharks teeth and some skate teeth, snfd some ancient shells. many ending up on the beach. Because it was an exclusive (incl no blacks as far as I know) private beach there were gobs of sharks' teeth -- the few public beaches pay or state parks are well picked over. My parents would walk up and down the tideline, picking them up. Many gloss eroded to varying degrees. Dad made wall art out of them. Never found a megalodon tooth. Why are they so very rare? Those big babies were shedding teeth like crazy. The population was apparently very low, which left the taxon vulnerable to extinction.

Of course this encouraged my interest in paleo. 

Next decade my brother and (later ex) wife snuck onto the beach. She happened to find a possible megalodon tooth to my brother's vexation because it was hers. She may still have it, but is not sure because she cannot get through her hoard of stuff she will never be able to sort through. Not sure how big it was. I have a 40 mm tooth that might be it, a ran a pic (attached) by a paleoshark guy, and he said it may be a juvie megalodon, or a relation. 

When doing volunteer work at the Smithsonian in the 70s I did ink Calvert shark teeth drawings for a pamphlet. At the time I thought it was a nice start to a career in paleoart doing something for the USNM!:) It was classic rip off of a newbie artist in that I was not paid:(, and they soon hired some incompetent to illustrate the upcoming dinohall with drawings that could have been done in the 50s:(:(

I used to miss going to the beach for the memories, and it being pristine, and the fossils. cannot get to it it being private. Sad to say no longer want to visit. In early 80s brother and I asked the community guard if we could go to down to the shore for an hour for old times sake. I was most disturbed to see the beach was only half as broad as it had been just two decades before. Western shore of bay is eroding about a foot a year (partly from the big waves of the cargo ships many times a day, mainly storms), so that is about right. At least teeth were still abundant with few having access to them. In this century took a look at Google maps. Beach gone and replaced by rock wall. Asked the head of the community association and she said the big 03 hurricane Isabel was the last blow. Houses on the beach road may be in danger at some point.

The on the beach part of the community put in back in the early 50s was not the best idea. Beach should have been given lots of back space to erode naturally. 

GSPaul