Thursday, September 5, 2019

Describing the impossible: a sauropod fossil from Cuba

A joint effort of Cuban-Argentinian paleontologists have recently published a detailed description of a dinosaur fossil found in the rocks of Cuba. With it, the researchers concluded that the fragmentary remain could have belonged to a rare dinosaur group that inhabited the surrounding landmasses of the proto-Caribbean Sea, preserving it in rocks that are now part of the Cuban terrain.

The interesting fossil was discovered at the start of the 20th century, in Jurassic-age rocks of the Jagua Formation, which crop out near Viñales, western Cuba. The fossil, however, did not gain certain attention until it was described and figured in a small note published by the Cuban geologist Alfredo de la Torre y Callejas, in 1949. In it, de la Torre credits the discovery to America Ana Cuervo, a professor of Geology and Paleontology at the University of Havana, and who had published several articles on Cuban fossil reptiles. Apparently, professor Cuervo donated the specimen to the University’s museum, where it was later available to de la Torre.


Metacarpal position for the somphospondylan sauropod from Cuba.
With insert of original specimen found by Prof. America A. Cuervo.
Courtesy of Yasmani Ceballos.
Unfortunately, the fossil has been lost since, and its whereabouts are still a mystery. All that remains of the enigmatic fossil are de la Torre’s vague descriptions and the small photograph published in 1949 (see figure below). Classifying it, based on such scanty data, has no doubt been challenging for the research team, but also very rewarding for Cuban paleontology. Comprising a  rare and noteworthy record indeed.

The research team, composed of Yasmani Ceballos Izquierdo – an upcoming Cuban paleontologist – and Dr. Manuel Iturralde-Vinent – the Cuban geologist-paleontologist extraordinaire, were led by the Argentinian dinosaur specialist Dr. Sebastián Apesteguía. Together, they recently published the interesting findings of their study in the prestigious journal Historical Biology.

Based on detailed comparisons, they have been able to identify the lost fossil bone as pertaining to the hand bone – a metacarpal – representing an old lineage of the Somphospondylii or a basal titanosaurid. These dinosaurs belonged to a group of giant herbivore sauropods that inhabited the coastal lands of Laurasia and Gondwanaland.

Alliance between Cuban and Argentinian paleontologists has spanned over a hundred years, starting with the Argentinian paleontologist Florentino Ameghino, who collaborated with Cuban researchers through the late 19th century. During the 1990s, Dr. Manuel Iturralde worked with Dr. Zulma Gasparini in the identification of rare reptilian fossils found in Jurassic-age rocks from Cuba. The most recent collaboration with Dr. Sebastián Apesteguía, like in the past, has no doubt bore fruitful results.


Metacarpal from somphospondylan sauropod from Cuba.
Original specimen found by Prof. America A. Cuervo.
Courtesy of Yasmani Ceballos.
 
Not only is this the first and only dinosaur yet reported from Cuba, but the fossil is also of biogeographical importance. It brings evidence of the extinct animals that inhabited the area that was to become the Caribbean Sea and some of its islands, like Cuba, several millions of years before the end-Cretaceous mass extinction that wiped out the dinosaurs.

Idealized scene of the western Tethys - early Caribbean seaway, and fauna
known from fossil remains found in Cuba.
Artwork by Roilan. Courtesy of Yasmani Ceballos.

After the supercontinent Pangea broke up, around 200-180 million years ago, it divided into several landmasses. Some to the northern hemisphere, others to the southern hemisphere. Laurasia is the landmass that existed when the North American continent was interconnected to its Eurasian counterpart, several hundred million years ago. The surrounding landmasses had a narrow seaway in which this fossil was probably washed into. The rocks of the bottom of that seaway have long since moved and incorporated to form parts of the main island of Cuba. This fossil, among other biological remains known from similar rocks formations, support the presence of emerged land nearby the proto-Caribbean seaway – known as the western Tethys.


The Earth during the Jurassic period (~200 -145 million years ago). Red circle shows area of proto Caribbean
Artwork and geologic interpretation by Christopher Scotese.


Acknowledgments


I extend my thanks to and appreciation for Yasmani Ceballos, who shared revealing information to prepare this post.

Recommended citation:


Apesteguía, S., Ceballos Izquierdo, Y., and Iturralde-Vinent, M. (2019). New taxonomic assignment for a dinosaur sauropod bone from Cuba. Historical Biology, https://doi.org/10.1080/08912963.2019.1661406