Psammosteida

Psammosteida
Temporal range: Devonian (Emsian–Frasnian)
Drepanaspis gemuendenensis reconstruction
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Infraphylum: Agnatha
Class: †Pteraspidomorpha
Subclass: †Heterostraci
Order: †Pteraspidiformes
Suborder: †Psammosteida
Kiaer, 1932
Taxa

Psammosteida also called as Psammosteoidei is a suborder of pteraspidid heterostracan agnathans. The psammosteids had broad, flattened bodies, suggesting a predominantly benthic habit. The earliest unequivocal psammosteid is Drepanaspis of Early Devonian Germany. Other notable psammosteids include Psammosteus, and Obruchevia, two genera of enormous species with dorsal shields around one meter in diameter. The Psammosteids were the only heterostracans to survive to the end of the Devonian, where they finally perish during the Hangenberg event.[citation needed]

Classification

Internal relationships

Taxonomy

The following families and genera were recognised by Glinskiy (2017) in the suborder Psammosteoidei:

Suborder Psammosteoidei (sensu Psammosteida Kiaer, 1932 emend. Tarlo, 1962)

Phylogeny

An analysis by Glinskiy in 2017 obtained the following phylogenetic tree by strict consensus:

Psammosteoidei

External relationships

A 2025 comprehensive analysis on pteraspidomorph relationships by Randle et al. retained the placement of Psammosteoidei within Pteraspidiformes, with Anchipteraspididae as the deepest branching Pteraspidiformes.

References

  1. 1 2 Randle, Emma; Keating, Joseph N.; Sansom, Robert S. (2025). "A phylogeny for Heterostraci (stem-gnathostomes)". Papers in Palaeontology. 11 (5) e70030. doi:10.1002/spp2.70030. hdl:1983/53eb7ef8-173d-42a0-9ab7-acee7506f464. ISSN 2056-2802.
  2. ↑ Dec, Marek (2019). "Revision of the Early Devonian psammosteids from the "Placoderm Sandstone": Implications for their body shape reconstruction" (PDF). Palaeontologia Electronica. 22 (2). doi:10.26879/948. Retrieved 2025-06-10.
  3. 1 2 3 4 5 Glinskiy, Vadim (2017). "Phylogenetic relationships of psammosteid heterostracans (Pteraspidiformes), Devonian jawless vertebrates". Biological Communications. 62 (4): 219–243. doi:10.21638/11701/spbu03.2017.402.