Cheiracanthus latus
Infraphylum Gnathostomata, Class Acanthodii
Geological Time: Middle Devonian
Size (25.4 mm = 1 inch): Fossil is 93 mm in length on 68 mm by 50 mm matrix
Fossil Site: Tynet Burn, Grampian, Scotland
Fossil Code: UKF111
Price: $295.00 - sold
 Description:
The Acanthodians are jaw-bearing fish who still are the subject
of dispute over their systematic position. Most possessed highly-advanced,
spindle-shaped bodies thought to have made them swift swimmers.
The body was covered in small mosaic-like scales. They possessed
small teeth which were typically confined to the lower jaw; some
were toothless. The feature they all share in common is the fact
that all fins other than the caudal are supported by massive spines
formed of dentine. Indeed, the name Acanthodii is derived from
the Greek word for spine. The oldest acanthodian lived during the
late Ordovician. They reached their peak during the Devonian, and
became extinct during the Great Dying of the end-Permian extinction.
This well-preserved example is known as Cheiracanthus, a name that
means “hand spine”. Unlike many acanthodians this one
had a single dorsal fin and was more stocky of build, hence the
specific name latus, meaning wide. While the head is indistinct
(I have included a high contrast photo to enhance details), the
fine scales and spines are very much on display. Full specimens
are only found in Scotland , but distinctive scales have been found
worldwide. |
