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Hybocrinida

Crinoidea - Hybocrinida

Synonymy list
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RankNameAuthor
kingdomAnimalia()
Triploblastica
Nephrozoa
Deuterostomia
Ambulacraria
phylumEchinodermata
subphylumCrinozoaMatsumoto 1929
RankNameAuthor
classCrinoideaMiller 1821
subclassPentacrinoideaJaekel 1918
infraclassInadunata(Wachsmuth and Springer 1897)
Cladida(Moore and Laudon 1943)
superorderPorocrinoidea
orderHybocrinidaJaekel 1918
orderHybocrinidaJaekel 1918

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
ReferenceDiagnosis
D. F. Wright et al. 2017The Hybocrinida is stem-defined as the most inclusive clade containing Hybocrinus conicus Billings, 1857 and Hybocystites problematicus Wetherby, 1880 but not Porocrinus conicus Billings, 1857 and Carabocrinus radiatus Billings, 1857.

In addition to having a pseudomonocyclic calyx (infrabasals absent), hybocrinids are characterized by a number of unusual apomorphies that distinguish them from Porocrinids (and all other crinoids). Many of these traits are similar to those typically present in blastozoan echinoderms, including reduction in the number of arms, modification of food-gathering appendages to be recumbent (sometimes extending downward
over calyx plates), and reduction in the number of calyx plates (Sprinkle and Moore, 1978).

[Wright et al., 2017]