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TF0902 Irregular echinoid
Title
TF0902
Irregular echinoid
Subject
Location
Coralline Oolite, Upware, Cambridgeshire
Description
Species
depressus Lestre
Stratigraphic Range
Jurassic
Taxonomy
Phylum: Echinodermata
Class: Echinoidea
Subclass: Irregularia
Order: Holectypoida
Genus: Holectypus
Class: Echinoidea
Subclass: Irregularia
Order: Holectypoida
Genus: Holectypus
Distinctive Features
Bilateral symmetry
Five radial ambulacra
Spine attachment scars (very small)
Peristome and anus out of line
Five radial ambulacra
Spine attachment scars (very small)
Peristome and anus out of line
Preservation
Shell mineral replacement
Sediment infil
Disarticulation of spines
Sediment infil
Disarticulation of spines
Advanced notes
This is a primitive irregular echinoid which would have had a functional jaw apparatus (not preserved) held within the peristome. The anus has migrated and the symmetry is bilateral, so this echinoid is clearly identifiable as irregular.
Citation
“TF0902
Irregular echinoid,” 1A Collections, accessed April 9, 2024, https://wserv3.esc.cam.ac.uk/p1acollections/items/show/132.
Irregular echinoid,” 1A Collections, accessed April 9, 2024, https://wserv3.esc.cam.ac.uk/p1acollections/items/show/132.