Proarticulata

Proarticulata Temporal range: Late Ma PreꞒ Ꞓ O S D C P T J K Pg N
Fossil of Dickinsonia costata
Fossil of Spriggina
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Stem group:	Bilateria
Phylum:	†Proarticulata Fedonkin, 1985
Class / Family
†Vendiamorpha Fedonkin, 1985 † Vendiidae Ivantsov †Dipleurozoa Harrington & Moore, 1955 †Dickinsoniidae Harrington & Moore, 1955 †Cephalozoa Ivantsov. 2004 †Sprigginidae Glaessner, 1958 †Yorgiidae Ivantsov, 2001 For more taxa, see text

Proarticulata is a proposed

Vendiamorpha

The body is completely segmented, with all isomers curved towards the posterior, and the first isomer is normally much larger than the rest. The first two isomers at the anterior dorsal end are partly fused. (e.g., Vendia, Paravendia and Karakhtia).^{[6][13][14][15]}

Cephalozoa

These proarticulatans are incompletely segmented, as the anterior zone is free of isomers, often making a "hairband" like appearance (example cephalozoans include

In Cephalonega stepanovi and Tamga hamulifera the zone containing the isomers is encircled by a peripheral, undivided zone.^[16] The Cephalonega's isomers are connected to each other, forming a body resembling a rubber raft; the Tamga's isomers are separated from each other, and do not touch.

In Lossinia, the center undivided region has no visible isomers, instead having the lobe-like isomers emanate from the periphery of the undivided region as "transverse articulations."^[16]

Dipleurozoa

The dipleurozoan body is subradial, divided by isomers entirely (e.g., Dickinsonia and Phyllozoon). Dickinsonia juveniles show undivided anterior areas but these regions were reduced in the course of ontogeny, and in the adult stages Dickinsonia-like proarticulates changed so radically that they became almost indistinguishable from isomers.^[13][16][18]

List of Proarticulata

Andiva ivantsovi

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Dickinsonia costata

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Spriggina floundersi

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Ovatoscutum concentricum

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Yorgia waggoneri

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Tamga hamulifera

Body fossils

• Armillifera Fedonkin, 1980^[19]

A. parva Fedonkin, 1980

• Andiva Fedonkin, 2002^[20]

A. ivantsovi Fedonkin, 2002

• Archaeaspinus Ivantsov, 2007^[6] (=Archaeaspis Ivantsov, 2001)^[16]

• Cephalonega Ivantsov et al., 2019^[21]

C. stepanovi (Fedonkin, 1976)^[16][22]

• Chondroplon Wade, 1971 (possible =Dickinsonia)

C. bilobatum Wade, 1971

• Cyanorus Ivantsov, 2004^[13]

C. singularis Ivantsov, 2004

• Dickinsonia Sprigg, 1947

D. costata Sprigg, 1947

D. menneri Keller 1976^[16] (=Vendomia menneri Keller 1976^[22])

D. tenuis Glaessner & Wade, 1966

• Ivovicia Ivantsov, 2007^[16]

I. rugulosa Ivantsov, 2007

• Karakhtia Ivantsov, 2004

K. nessovi Ivantsov, 2004

• Lossinia Ivantsov, 2007^[16]

L. lissetskii Ivantsov, 2007

• Marywadea Glaessner, 1976

M. ovata Glaessner & Wade, 1966

• Ovatoscutum Glaessner & Wade, 1966

O. concentricum Glaessner & Wade, 1966

• Paravendia Ivantsov, 2004^[6][13]

P. janae Ivantsov, 2001 (=Vendia janae Ivantsov, 2001)

• Podolimirus Fedonkin, 1983 (=Valdainia Fedonkin, 1983)^[23]

P. mirus Fedonkin, 1983 (Valdainia plumosa Fedonkin, 1983)

• Praecambridium Glaessner & Wade, 1966

P. siggilum Glaessner & Wade, 1966

• Spriggina Glaessner, 1958

S. floundersi Glaessner, 1958

• Tamga Ivantsov, 2007^[16]

• Vendia Keller, 1969^[6][13]

V. sokolovi Keller, 1969

V. rachiata Ivantsov, 2004

• ? Windermeria Narbonne, 1994

W. aitkeni Narbonne, 1994^[24]

• Yorgia Ivantsov, 1999^[7]

Y. waggoneri Ivantsov, 1999

Trace fossils

• Epibaion Ivantsov, 2002^[18][25]

E. axiferus Ivantsov, 2002.

E. waggoneris Ivantsov, 2011. This is a trace of Yorgia waggoneri

E. costatus Ivantsov, 2011. This is a trace of Dickinsonia costata

• Phyllozoon Jenkins & Gehling, 1978

P. hanseni Jenkins & Gehling, 1978

See also

• Articulata
• List of Ediacaran genera

References