Astadelphis

Astadelphis is a monotopic extinct genus of Globicephaline delphinid cetacean from the Pliocene of the Sabbie d'Asti Formation of the Piedmont region of Northern Italy. Its type and only species is 'A. gastaldii.'''''

Taxonomy and naming

The holotype of Astadelphis gastaldii was discovered in the late 19th century. It was named as an extinct species of the extant globicephaline genus Steno as Steno gastaldii by Brandt. However Bianucci reclasified it is under the new genus name of Astadelphis. A.gastaldii is the only species of this genus.

Palaeobiology

Trace fossils in the form of tooth marks on the bones of the holotype of Astadelphis gastaldii show that it was prayed on by a relative of the modern great white shark, Cosmopolitodus hastalis. The individual was attacked from below and behind, much like the modern great white shark does. The deepest bite marks on the dolphin's ribs indicate the shark aimed for the abdomen of its prey to inflict a fatal bite quickly and incapacitate its prey, and that when the dolphin was attacked a second time, it was bitten near the dorsal fin, suggesting that the dolphin rolled over while injured. The size of the bites indicates further that the shark responsible was estimated to be long.