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Helicoplacus

Helicoplacoidea - Helicoplacidae

Taxonomy

Helicoplacus was named by Durham and Caster (1963). Its type is Helicoplacus gilberti.

It was assigned to Helicoplacida by Durham (1967); to Helicoplacoidea by Durham and Caster (1963) and Sepkoski (2002); and to Helicoplacidae by Durham (1993) and Wilbur (2006).

Species

H. gilberti (syn. Westgardella blancoensis, H. everndeni, H. casteri, Westgardella firbyi, H. guthi, H. curtisi) (type species)

Synonyms

Westgardella was named by Durham (1993) [Sepkoski's age data: Cm Atda-u]. It is the type genus of Westgardellidae.

It was synonymized subjectively with Helicoplacus by Wilbur (2006).

It was assigned to Westgardellidae by Durham (1993); and to Helicoplacoidea by Sepkoski (2002).

Synonymy list

Year	Name and author
1963	Helicoplacus Durham and Caster p. 822 fig. 1
1967	Helicoplacus Durham p. 100
1993	Helicoplacus Durham p. 600
1993	Westgardella Durham p. 601
2002	Helicoplacus Sepkoski
2002	Westgardella Sepkoski
2006	Helicoplacus Wilbur p. 290

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Rank	Name	Author
kingdom	Animalia	()
—	Bilateria
—	Eubilateria	Ax 1987
—	Deuterostomia
—	Ambulacraria

Rank	Name	Author
phylum	Echinodermata
class	Helicoplacoidea
family	Helicoplacidae	Durham and Caster 1966
genus	Helicoplacus

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.

G. †Helicoplacus Durham and Caster 1963

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†Helicoplacus gilberti Durham and Caster 1963

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Invalid names: Helicoplacus casteri Durham 1993 [synonym], Helicoplacus curtisi Durham and Caster 1963 [synonym], Helicoplacus everndeni Durham 1967 [synonym], Helicoplacus guthi Durham 1993 [synonym], Westgardella blancoensis Durham 1993 [synonym], Westgardella firbyi Durham 1967 [synonym]

Invalid names: Westgardella Durham 1993 [synonym]

Diagnosis

Reference	Diagnosis
J. W. Durham 1967	Ambulacrum branched, plating simple, with large laterals and a few small medial plates.
J. W. Durham 1993	Helicoplacidae with longitudinal ridges or pus- tulose ornamentation on external surface of plates of medial column of interambulacra.
J. W. Durham 1993 (Westgardella)	Helicoplacids with 10 interambulacral areas between primary ambulacrum and its continuation in next volution; external surface of plates of medial interambulacral column smooth; plates often produced into distal angulation or prominent spine; tubefeet emerging from interior through grooves in sequential plates.
B. C. Wilbur 2006	Helicoplacoids with differentiated ambulacra and interambulacra. Coverplates and floorplates contiguous, with two coverplate rows, and a third covering the mouth.