Prehistoric Models: Early Chordates

Chordata are animals that possess a notochord (a flexible rod formed of a material similar to cartilage), a dorsal nerve cord, pharyngeal slits, and a post-anal tail. For simplicity I have included the infraphylum Agnatha meaning “without jaws“. Agnatha are more commonly referred to as jawless fish in the phylum Chordata, subphylum vertebrata.

Kingdom: Animalia – Phylum: Chordata – Family: Pikaiidae – Genus: Pikaia

(extinct primitive chordata)

Cambrian Period

Genus and Species: Pikaia gracilens

Pronounced: Pik-ay-ah

Named by: Charles Walcott, 1911

Classification: Phylum: Chordata – Family: Pikaiidae

Time: Middle Cambrian Period

Locality: Canada, British Columbia – Burges Shale 

Size: 38 millimeters or 1.5 inches

Diet: Unknown

Agnathajawless fish”

Domain: Eukaryota – Kingdom: Animalia – Phylum: Chordata – Infraphylum: Agnatha – Class: Pteraspidomorphi – Subclass: Heterostraci – Order: Pteraspiformes – Suborder: Pteraspidoidei – Family: Pteraspididae

(heterostracan vertebrates)

Devonian Period

Genus: Pteraspis ‭”Wing shield‭”

Pronounced: Teh-rass-pis

Species:P. crou chi, P. rostratus, P. stensioei

Named by: Agassiz – 1835

Classification: Phylum: Chordata – Infraphylum: Agnatha – Class: Pteraspidomorphi – Subclass: ‬Heterostraci – Order:‭ ‬Pteraspidiformes – Family:‭ ‬Pteraspidae

Known locations: Europe, particularly Belgium and Britain

Time period: Early to Middle Devonian (Lochkovian to Emsian)

Size: 20‭ ‬centimetres long.

Diet: Carnivore.

Domain: Eukaryota – Kingdom: Animalia – Phylum: Chordata – Infraphylum: Agnatha – Clade: Cephalaspidomorphi – Class: Osteostraci

(osteostraci meaning: “bony shells”)

Late Silurian to End Devonian

Genus: Cephalaspis‭ “Head shield‭”

Pronounced: Seff-ah-lass-pis

Species: C.‭ ‬lyelli

Named By: Louis Agassiz‭ ‬-‭ 1835 or ‬1846‭

Classification: Phylum: Chordata – Infraphylum: Agnatha – Class: ‬Osteostraci

Size: Approximately‭ ‬20‭ ‬to‭ ‬30‭ ‬centimetres long.

Known locations: Western Europe.‭ ‬North America

Time period: Early Devonian (Lochkovian to Emsian)

Diet: Carnivore/bottom feeder

<< Back to Echinodermata Models 

Specimen Gallery Homepage

Toys and Models Homepage

Next to Placoderm Models >>