Episode 54 is all about Becklespinax, a dinosaur known from three high spines.

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In this episode, we discuss:

• The dinosaur of the day: Becklespinax
• Name means Beckle’s spine
• Lived in the early Cretaceous, in what is now England
• Samuel Beckles, a fossil collector, found the first bones near East Sussex in the early 1850s
• He sent the bones to Richard Owen, who wrote about them in 1856. He classified it as Megalosaurus bucklandii (wastebasket taxon) Owen had Joseph Dinkel make a lithography, based on three back vertebrae with tall spines. This image appeared in an 1884 edition of 1855 volume of work on British fossils, which led some people to think the fossils were found around 1884 (instead of the 1850s).
• Owen thought the back vertebrae was part of the shoulder, and it’s thought he knew about these bones back in 1853 when he told Benjamin Waterhouse Hawkins to give the life-sized Megalosaurus sculpture in Crystal Palace Park a hump on its back.
• Since Becklespinax was discovered very early (when paleontologists first started finding dinosaurs), that’s why Owen assigned it to Megalosaurus and thought that based on one specimen Megalosaurus had a hump
• Richard Lydekker reclassified the vertebrae as part of Megalosaurus dunkeri in 1888 (a dinosaur from the Cretaceous named based on a tooth from Germany); Friedrich von Huene named a separate genus for Megalosaurus dunkeri in 1923, Altispinax (name means “high spines”). Megalosaurus dunkeri became Altispinax dunkeri, and the name was first used in 1939 by Oskar Kuhn
• But the tooth Altispinax was based on was undiagnostic, so Altispinax became a nomen dubium (and it was unclear the vertebrae were related to the tooth)
• So, in 1988 Gregory Paul renamed it Acrocanthosaurus? (yes he added a question mark) altispinax (with the species name the same as the old genus name to show they both referred to the vertebrae).
• Gregory Paul renamed Altispinax as Acrocanthosaurus based on the fact that Acrocanthosaurus had high neural spines and also lived in the early Cretaceous
• But Gregory Paul wasn’t sure about this classification (question mark). Because of this, in 1991 George Olshevsky gave it a new genus name in honor of Beckles, and it became Becklespinax altispinax.
• Other names such as Altispinax altispinax and Altispinax lyderkkerhueneorum are junior synonyms (referring to the same back vertebrae material)
• George Olshevsky said the fossils were sinraptorid (allosauroid theropods similar to Sinraptor) and that’s why he renamed it Becklespinax
• Gregory Paul estimated that Becklespinax weighed about 1 ton and was shorter than Acrocanthosaurus atokensis (which he estimated was 26 ft or 8 m long)
• The three back vertebrae have about 14 in (35 cm) high neural spines. Ralph Molnar said the two spines closest to the skull were fused (the closest spine is about 2/3 the height of the other 2 spines, and looks broken off, and the 2nd spine partly overgrows this gap; so Becklespinax probably had an injury and the wound closed from behind)
• But in 2003, Darren Naishgave said this gap was natural. He said Richard Owen had written about large depressions on the spine sides and said they were from pneumatisation (air cavities in tissue), which was the first time this was seen in a dinosaur (although in 2006 it was found that Christian Erich Hermann von Meyer had actually found this earlier, in 1837, with Saurischia in general)
• In 2010 a Concavenator back crest with only two high vertebrae showed that Becklespinax’s spine may be complete
• Because only three spines were found for Becklespinax, it’s hard to know exactly how the dinosaur looked (though there are theropods such as Acrocanthosaurus and Spinosaurus with high spines, but then Concavenator had a small hump with just two vertebrae
• Also Metriacanthosaurus, from the Jurassic in England, was a theropod with large neural spines
• Concavenator is a cousin of Acrocanthosaurus (Concavenator found in Spain)
• No better, more complete specimens found yet of Becklespinax, so hard to know for sure what it looked like
• But it resembles Concavenator, so probably also a carcharodontosaur with a sail back
• Though Concavenator and Becklespinax lived 10 million years apart, Naish has suggested the possibility they are the same genus (Concavenator corcovatus may be Becklespinax corcovatus, but without knowing more about how Becklespinax looked it’s hard to say)
• Based on Acrocanthosaurus and Concavenator, Becklespinax was a large predator with distinctive ridges and sails on its back. These ornaments may have been for display, a sign of dominance, or a way to know the dinosaur belonged to a species (though no one knows for sure)
• Probably ate small to medium sized sauropods (based on where and when it lived)
• Originally Olshevsky assigned Becklespinax to Eustrptospondylidae. But in 2003 Nash assigned it to Allosauroidea. Other researchers say its Tetanurae incertae sedis, which means it’s unclear where it falls in the group
• Allosauroidea is a superfamily that contains four familes (Metriacanthosauridae, Allosauridae, Carcharondontosauridae, Neovenatoridae)
• The oldest Allosauroidea dinosaurs are from the early Middle Jurassic, in what is now China
• They lived through the late Cretaceous
• They had long, narrow skulls, three-fingers on each hand, and “horns” or ornamental crests on their heads (Allosaurus is the best known)
• Tetanurae is a clad whose name means “stiff tails”
• Jacques Gauthier named Tetanurae in 1986, and they include theropods more closely related to modern birds than to Ceratosaurus
• They include most theropods, as well as birds
• They appeared in the early or middle Jurassic
• Large spinosaurids and allosaurids lived in the late Jurassic and early Cretaceous (particularly Gondwana), but died out before the end of the Cretaceous (may be because of competition from abelisaurids and tyrannosaurids). Now modern birds are the only living animals in the Tentanurae clade
• Carcharodontosaurids are a family named by Ernst Stromer in 1931 to include new species of Carcharondontosaurus. In 1995,
• Giganotosaurus was added to the family, and some paleontologists consider Acrocanthosaurus part of the family
• The name means “shark toothed lizards”
• They were carnivorous theropods
• The largest were 46 ft (14 m) long and the smallest were 20 ft (6 m) long
• Spinosaurids and carcharondontosaurids were the largest predators in the early and middle Cretaceous in Gondwana
• Fun fact: The formation of the Isthmus of Panama (between 2 and 15 million years ago) is probably the most important geological event since dinosaurs went extinct. It:
  • Separated the Caribbean sea from the Pacific, causing an increase in diversification in those areas while merging North and South america
  • Forced many South American animals to go extinct, due to North American animals, although some South American animals made it in North America as well
  • Created The Gulf Stream
  • Made Europe and Eastern North America warmer
  • Made the Atlantic to become more salty then the Pacific ocean