Gyracanthus

Taxonomy

Gyracanthus

Kingdom: Animalia
Phylum: Chordata
Class: Acanthodii
Order: Climatiiformes
Family: Gyracanthidae
Genus: Gyracanthus
Species: Gyracanthus sherwoodi
Author Citation “Gyracanthus” sherwoodi (Gnathostomata, Gyracanthidae) from the Late Devonian of North America Author(s): Daniel Snyder, Susan Turner, Carole J. Burrow and Edward B. Daeschler Source: Proceedings of the Academy of Natural Sciences of Philadelphia, 165():195-219. Published By: The Academy of Natural Sciences of Philadelphia https://doi.org/10.1635/053.165.0111

Geological Time Scale

Eon: Phanerozoic
Era: Paleoproterozoic
Period: Devonian
Sub Period: None
Epoch: Late
International Age: Famennian

Stratigraphy

Catskill Formation

Provenance

Collector: Paul and Ian Bourdon
Date Collected: 09/18/2021
Acquired by: Field Collection

Location

Red Hill
Clinton
Pennsylvania
United States

• catskill
• devonian
• pennsylvania

Comments

Gyracanthus is a cartilagenous gnathostome possibly a stem or sister clade to the Chondrichthyans.  Most common fossils found are the fin spines but scapulocoracoids are not uncommon. Fossils here are result of collecting over 8 years from 2013.

diagnosis.—Medium-sized gyracanthid fish, maximum estimated body length approximately 1 meter.

 

Maximum fin spine length estimated 375 mm. Ridge width constant at maturity, ridge width constant along insertion-exsertion boundary at maturity, interridge width equal to or less than ridge width. Cristate tubercles ≤2 mm height, ≤2mm width, 9-11/cm proximally on pectoral fin spines, 8/ cm proximally on pelvic fin spines, 15/cm proximally on dorsal fin spines where preserved. Major and minor axes on tubercle, apex oriented oblique to underlying ridge. Pectoral fin spine inserted approximately one-third the length of the fin spine, ridge width constant along insertion-exsertion boundary at maturity, maximum fin spine ridge chevron angle along leading edge 90°, ornamented ridge dorsal to posteromedial groove.

 

Two types of pelvic fin spines, one narrower with extensive exserted area, one wider and more robust with extensive inserted area, both with inserted area extending greater than half the length of the spine. Pelvic fin spine ridges curved retrorse towards midline. Median fin spines approximately symmetrical, comparable to paired fin spines but smaller and straighter distinct anterior and posterior dorsal fin spines. Prepectoral ventral plate with more than 30 tubercle rows, largely subparallel, some bifurcating, curving to the middle only at the extrema, convergent towards the lateral edge; prepectoral ventral plate inserted area at least a third of the width of the plate.