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An international team of paleontologists from Austria and Switzerland have discovered an exceptionally well-preserved skeleton of ASTERACANTHA accomplished, a species of hybodontiform shark that lived around 150 million years ago (Jurassic period), in the famous Solnhofen limestones in Germany.
Provisional reconstruction of the life of the hybodontiform shark ASTERACANTHA accomplished. Image Credit: Sebastian Stumpf / Fabrizio De Rossi.
“Hybodontiform sharks are the closest relatives of modern sharks and rays,” said Dr Sebastian Stumpf of the University of Vienna and his colleagues.
“They first appeared in the late Devonian, around 361 million years ago, survived two of the five great Phanerozoic mass extinction events, and finally disappeared in the late Cretaceous there is about 66 million years old.
“These sharks had two dorsal fins, each supported by a prominent fin spine.”
“Their body size varied from a few centimeters to around 3 m (10 feet) in maximum length, which makes Asteracanthus one of the greatest representatives of his group and of his time.
“In contrast, modern sharks and rays, which were already diverse during the Jurassic, only reached a maximum size of 2 m (6.6 feet) in maximum length in very rare cases.
ASTERACANTHA accomplished from Lower Tithonian from Solnhofen, Bavaria, Germany: (A) interpretive line drawing; (B) plate containing the specimen; (C) Close-up view of the anterior dorsal fin spine; (D) Close-up view of the posterior dorsal fin spine; (E) provisional reconstruction of a woman’s life ASTERACANTHA accomplished. Abbreviations: adfs – spine of the anterior dorsal fin, af – anal fin, bv – basiventral, cf – caudal fin, ebr – epibranchy, lal – lateral line, Mc – Meckel’s cartilage, nc – neurocranium, notc – notochord, pcf – pectoral fin, pdfs – posterior dorsal fin spine, plr – pleural rib, pq – palatoquadrate, pvf – pelvic fin, scc – scapulacoracoid. Scale bars – 50cm (A, B) and 10cm (C, D). Image Credit: Stumpf et al., doi: 10.1002 / spp2.1350.
In the new research, paleontologists examined an exceptionally well-preserved new skeleton of ASTERACANTHA accomplished with dentition and fin thorns from Solnhofen limestones.
“Asteracanthus was scientifically described over 180 years ago by Swiss-American naturalist Louis Agassiz on the basis of fossil spines isolated from the dorsal fin, ”they said.
“However, articulated skeletal remains have never been found – until now.”
According to the team, the dentition of ASTERACANTHA accomplished contained over 150 teeth, each with a well-developed central cusp which was accompanied on both sides by several smaller cusplets.
“This specialized type of teething suggests that Asteracanthus was an active predator feeding on a wide range of prey, ”said Dr Stumpf.
“Asteracanthus was certainly not only one of the largest cartilaginous fish of his time, but also one of the most impressive.
The results were published in the journal Paleontology articles.
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Sebastian stumpf et al. A unique hybodontiform skeleton provides new insight into the life of Mesozoic chondrichthyans. Paleontology articles, published online January 13, 2021; doi: 10.1002 / spp2.1350
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