Paralititan (meaning "tidal giant") is a genus of sauropod dinosaur that lived in present-day Egypt during the Late Cretaceous period. It was described by American paleontologist Joshua B. Smith and colleagues in 2001. The genus contains a single species, Paralititan stromeri, named based on a fragmentary skeleton including vertebrae and limb bones. These fossils were unearthed by an American expedition to the Bahariya Oasis in western Egypt in rock layers of the Bahariya Formation. This formation dates to the Cenomanian stage of the Late Cretaceous, which lasted 101 to 94 million years ago. An incomplete dorsal (back) vertebra that had been described by German paleontologist Ernst Stromer in 1932 was also assigned to Paralititan. However, this vertebra had been destroyed during the Bombing of Munich in World War II. Like other sauropods, Paralititan was a four-legged herbivore with a long neck ending in a small head. It was at one point considered one of the largest dinosaurs known. More recent estimates place it at 26 meters (85 feet) in length and 30–55 tonnes (33.1–60.6 short tons) in mass. This would make it a large sauropod, but not as huge as genera like Argentinosaurus and Puertasaurus. Its robust humerus (upper arm bone) is 1.69 meters (5.5 feet) in length and bears a large deltopectoral crest (a forward directed bony flange). The caudal (tail) vertebrae are wider than tall and lack pleurocoels (large cavities that stored air sacs) on their sides. Paralititan is a member of the Saltasauridae, a family within the sauropod group Titanosauria. Some saltasaurids, including Saltasaurus itself, preserve dorsal osteoderms (bones formed in the skin), though such bones are unknown for Paralititan. Paralititan coexisted with other dinosaurs such as the sauropod Aegyptosaurus, the theropods Tameryraptor, Spinosaurus, and Bahariasaurus, and an unnamed abelisaurid theropod. During the Cenomanian, the Bahariya Formation was on the margin of the Tethys Sea, and represented a large network of mangrove swamps, rivers, and tidal flats.
Discovery In 1999, researcher Joshua Smith rediscovered a site in the Bahariya Oasis of Egypt, known as Gebel el Dist, that had formerly been explored by Austro-Hungarian paleontologist Richard Markgraf between 1912 and 1914. The fossils that Markgraf found, including those of dinosaurs like Spinosaurus and Tameryraptor, had been shipped to Germany where they were described by German paleontologist Ernst Stromer. Markgraf had evidently removed all more complete skeletons, leaving only limited remains behind. In 2000, an American expedition was mounted to revisit the site but failed to find any dinosaur skeletons. At a new site, the nearby Gebel Fagga, the expedition succeeded in locating a partial sauropod skeleton.
This incomplete skeleton consists of two sacrals (hip vertebrae, probably the 5th and 6th), the first caudal (tail vertebra), another caudal from the front portion of the tail, dorsal and sacral ribs, incomplete scapulae (shoulder blades), a complete right and an incomplete left humerus (upper arm bone), the lower end of a metacarpal, and several additional elements. All of these fossils were transported to the Egyptian Geological Museum, Cairo and deposited under catalog number CGM 81119. Gebel Fagga and Gebel el Dist are sandstone outcrops of the Bahariya Formation, dating to the Cenomanian stage of the Late Cretaceous period. This makes these fossils around 101 to 94 million years ago old. In 2001, an international crew made up of paleontologist Joshua B. Smith and colleagues described the partial skeleton as a new genus and species of sauropod dinosaur, named Paralititan stromeri. They established this skeleton, CGM 81119, as the holotype (name-bearing) specimen. The generic name, Paralititan, derives from the Greek para, meaning 'near', halos 'sea', and titan, as in the Greek Titans. The specific name is in honor of Stromer, who first established the presence of dinosaur fossils in the Bahariya Oasis during a 1911 expedition. The entire name therefore translates to "Stromer's tidal titan" or "Stromer's tidal giant", in reference to the paralic tidal flats the dinosaur lived on. Additionally, Smith and colleagues assigned a large anterior dorsal (vertebra from the front portion of the trunk), cataloged at the Paläontologisches Museum München (Bavarian State Collection of Paleontology) under SNSB-BSPG 1912V11164, to Paralititan stromeri. Stromer, in 1932, assumed that this vertebra belonged to an undetermined "Giant Sauropod", but it was destroyed alongside other fossils from the Bahariya Formation during the Bombing of Munich in World War II. Several isolated sauropod fossils, mainly consisting of caudal vertebrae, were assigned by Stromer to the other Bahariya sauropod Aegyptosaurus, but these may belong to Paralititan instead.
Description
Size Only 5.1% of Paralititan's skeleton is known, so its exact size is difficult to estimate. The limited material, especially the long humeri, suggested that it was one of the most massive dinosaurs ever discovered, with an estimated weight of 59 t (65 short tons) according to a 2001 study. Joshua Smith, who informally led the research team that found Paralititan, told an interviewer, "It was a truly enormous dinosaur by any reckoning". The complete right humerus measures 1.69 meters (5.5 feet) long which at the time of discovery was the longest known in a Cretaceous sauropod; this was surpassed in 2016 with the discovery of the titanosaur Notocolossus, which includes a 1.76 m (5 ft 9 in) humerus. Using Saltasaurus as a guide, American paleontologist Kenneth Carpenter estimated its length at around 26 m (85 ft) in a 2006 study.
American researcher Scott Hartman estimated that the animal was massive, but still smaller than the biggest titanosaurs such as Puertasaurus, Alamosaurus, and Argentinosaurus. In the 2010 edition of his book The Princeton Field Guide to Dinosaurs, American researcher Gregory S. Paul estimated its length at 20+ meters (66+ ft), and its weight at 20 tonnes (24.2 short tons). In 2016, using equations that estimate body mass based on the circumference of the humerus and femur of quadrupedal animals, Argentine paleontologist Bernardo González Riga and colleagues gave a weight estimate of ~50 t (55.1 short tons) for Paralititan. In 2019, Paul estimated Paralititan between 30 and 55 tonnes (33.1–60.6 short tons) in weight.
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