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Hystrichopsydrax
Taxonomy
Hystrichopsydrax was named by Guensburg (1988) [Sepkoski's age data: O Ashg-m]. It is not extant. Its type is Hystrichopsydrax sandersi.
It was assigned to Agelacrinitidae by Guensburg (1988); and to Isorophida by Sepkoski (2002).
It was assigned to Agelacrinitidae by Guensburg (1988); and to Isorophida by Sepkoski (2002).
Species
H. sandersi (type species)
Synonymy list
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
Diagnosis
Reference | Diagnosis | |
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T. E. Guensburg 1988 | Isorophina with low domal theca, short straight ambulacra; oral area includes four large primary orals; ambulacral coverplates probably forming alternating multiple biseries; anal structure valvular, cone shaped, composed of upturned lath-shaped plates; interambulacrals not abutting, consist of tacklike spinose plates interspersed with small ovoid plates; proximal peripheral rim circlet comprised of large exteriorly curved plate ring, plates mutually articulating along vertical sutures; succeeding peripheral rim plates spinose. |