Parahelicoprion

Parahelicoprion is an extinct genus of shark-like eugeneodontid holocephalids from the Permian of the Ural Mountains and Copacabana Formation, Bolivia.[1] The genus name, from "nearly coiled saw" in Greek, directly refers to Helicoprion, a related holocephalid that shares similar traits to it, including the helical whorl of teeth.

Parahelicoprion
Temporal range: Early Permian
~298.9–295 Ma
Parahelicoprion clerci.jpg
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Eugeneodontida
Family: Helicoprionidae
Genus: Parahelicoprion
Karpinsky, 1924
Type species
Helicoprion clerci
Karpinsky, 1916
Species
  • P. clerci (Karpinsky, 1916)
  • P. mariosuarezi Merino-Rodo & Janvier, 1986

DescriptionEdit

One of the primary qualities that separate Parahelicoprion from Helicoprion is the shape, thickness, and angle of the tooth whorl. Its teeth protrude outwards not like a tightly coiled saw, but instead a curved arrangement of cutting blades indicating it relied less on crushing slow-moving invertebrates and catching cephalopods, or other small mollusk prey, but inflicting traumatic damage against more durable, faster prey.[2] Their teeth grew at a much slower pace than those of other whorl-tooth sharks, resulting in a depreciated spiral, growing only half of the teeth a Helicoprion would grow in its lifetime. The tooth spiral also was able to indicate the age of the eugeneodontidans in question.[3]

The fossils of Parahelicoprion indicate an animal that was overall similar in size but more slender and less heavy than Helicoprion which measured over 25 ft (7.6 m) in length.[4]

PaleobiologyEdit

Parahelicoprion is thought to have been a nektonic carnivore that probably preyed upon a variety of different species, using its blade-like teeth to cut at exposed flesh like a hatchet or wedge.[5]

ReferencesEdit

  1. ^ Merino-Rodo, Dagmar; et al. (1986). "Chondrichthyan and actinopterygian remains from theLower Permian Copacabana Formation of Bolivia". Geobios. 19 (4): 479–493. doi:10.1016/S0016-6995(86)80005-5.
  2. ^ http://dinonews.net/forum/paleoactus.php?msg=168926 Parahelicoprion and Agassizodontidea
  3. ^ Brad Matsen and Ray Troll (October 25, 2012). "Planet Ocean: A Story of Life, the Sea, and Dancing to the Fossil Record".
  4. ^ Tapanila, L.; Pruitt, J.; Wilga, C.D.; Pradel, A. (2020). "Saws, Scissors, and Sharks: Late Paleozoic Experimentation with Symphyseal Dentition". The Anatomical Record. 303: 363–376. doi:10.1002/ar.24046.
  5. ^ "Fossilworks: Parahelicoprion".