Belongs within: Opisthokonta.
Contains: Volborthellida, Porifera, Rangeomorpha, Frondomorpha, Erniettomorpha, Eumetazoa.
The Metazoa, animals, are generally multicellular and phagotrophic organisms with collagenous connective tissue uniting two dissimilar epithelia (Adl et al. 2012), though some of these features have been lost in derived parasitic forms such as Myxozoa. Relationships of the major subdivisions of animals remain contentious; classic morphology has favoured a basal, possibly paraphyletic position for sponge-grade taxa (Porifera) relative to a monophyletic tissue-grade clade (Ctenophora, Cnidaria, Bilateria). Conversely, some recent molecular studies have suggested that sponge-grade animals may be derived from tissue-grade ancestors. Also lacking tissue structure is the small, flat, amorphous marine animal Trichoplax adhaerens, which moves by means of cilia on the cell surfaces and feeds on microscopic algae by lifting the body to form a ventral cavity into which digestive enzymes are released. The body of T. adhaerens possesses two layers of epithelial cells with a middle layer of syncytial contractile fibrous cells (Adl et al. 2012).
The earliest generally accepted metazoans are known from the Ediacaran period of the late Precambrian. Earlier, supposedly worm-like fossils described by Sun et al. (1986) as Pararenicola huaiyuanensis and Protoarenicola baiguashanensis have been disputed by later authors. Ediacaran taxa include the Arboreomorpha, Rangeomorpha and Erniettomorpha, sessile organisms sometimes united in a single grouping called the Petalonamae. Theories about the affinities of Ediacaran organisms have been heavily dependent on interpretations of their internal structure. Whereas some authors have seen them as entirely soft-bodied organisms comparable in structure to modern coelenterates, others have argued that their manner of preservation implies the presence of a leathery cuticle unlike that of any modern organism (Runnegar 2022). Authors have also disagreed whether Ediacaran taxa exhibited fed via direct uptake of food particles, or obtained nutrition osmotrophically or via endosymbiotic micro-organisms. Erniettomorpha and Rangeomorpha may be placed closer to modern tissue-grade animals by the evolution of directional, determinate growth patterns instead of the fractal growth exhibited by Arboreomorpha.
The phylogenetic relationships of a number of other fossil animal groups are also unknown. The Suvorovellidae are calcareous fossils from the uppermost Precambrian with double-walled, saucer-shaped or irregularly discoidal skeletons lacking structural elements between the walls (Glaessner 1979). The Brooksellidae are early Palaeozoic medusoid structures whose organic origins have been questioned by some authors. Namapoikia rietoogensis is a sessile, reef-forming organism with a skeleton of polygonal to labyrinthine tubules known from the latest Precambrian (Wood et al. 2002).
Articles on Metazoa
Salinella: what the heck was it?
Tons of little tubes
More little tubes—not just tons but tonnes
A sclerite mystery
Typhloesus: the ‘alien goldfish’ of Bear Gulch
Systematics of Metazoa
<==Metazoa (see below for synonymy)BJ17
|--Trichoplax von Schulze 1883HCH18, AS12 [Placozoa]
| `--T. adhaerensCV16
`--+--PoriferaHCH18
`--+--RangeomorphaR22
`--+--+--PambikalbaeHCH18
| `--FrondomorphaR22
`--+--ErniettomorphaNS93
`--EumetazoaHCH18
Metazoa incertae sedis:
Namapoikia Wood, Grotzinger & Dickson 2002WGD02
`--*N. rietoogensis Wood, Grotzinger & Dickson 2002WGD02
YaworiporaWGD02
Rosellatana jamesi Kobluk 1984NS93
Podolimirus mirusIF02, EL11
Neotricula apertaLO03
Cleisopus gloriamarisNN03
Caveasphaera costataX04
Megaclonophycus onustusX04
Spiralicellula bulbiferaX04
Eurytholia Sutton, Holmer & Cherns 2001SHC01
|--*E. prattensis Sutton, Holmer & Cherns 2001SHC01
`--E. elibata Sutton, Holmer & Cherns 2001SHC01
Dimorphoconus granulatus Donovan & Paul 1985SHC01
Jennaria pulchra Rieger 1991ZHT01
Pseudomytiloides dubiusBL78
ParastromatoporaHS02
SestromellaHS02
ChaetetopsisHS02
Poterion neptuniF79
Microcordyla asteriaeBK77
StematumeniaMK83
|--S. foetidaMK83
|--S. strobilinaMK83
`--S. variabilisMK83
Hemectyon feroxMH96
SpeophilosomaT07
|--S. koyamaT07
`--S. tottorienseT07
Lycocerus suturellusT07
Parechthistatus gibberT07
Parapodisma setouchiensisT07
ArcuphantesT07
|--A. hibanusT07
|--A. iharaiT07
|--A. saitoiT07
`--A. tsurusakiiT07
‘Leptophyllus’ Quenstedt 1876 non Hope 1842FT93
Paracharnia dengyingensisXS05
Pararenicola Wang 1982 [incl. Paleorhynchus Wang 1982]SWZ86
`--*P. huaiyuanensis Wang 1982 (see below for synonymy)SWZ86
Protoarenicola Wang 1982SWZ86
`--*P. baiguashanensis Wang 1982SWZ86
VolborthellidaWS93
Ptychoderma australiensisH09
Limnorea Goldfuss 1826BR05
AncodonS61
|--A. gorringeiS61
`--A. parvusS61
Conigalea Ivanov 1995 [Actinaculata, Conigaleidae, Conigaleoida, Marinaculata]I95
`--*C. otschevi Ivanov 1995I95
Basiliella wusungensisD82
AttungaiaF71
|--A. cloacataF71
`--A. wellingtonensis Pickett 1967F71
Columellaespongia woolomolensis Pickett 1967F71
Devonospongia clarkeiF71
Hyalostelia australis Etheridge 1916F71
Varneycoelia favosa Pickett 1967F71
Ramenta Jiang in Luo et al. 1982P08
Ernogia Jiang in Luo et al. 1982P08
Stenothecopsis Cobbold 1935F62
`--*S. heraultensis Cobbold 1935F62
Scenellopsis Resser 1938F62
`--*S. clotho (Walcott 1905) [=Scenella clotho]F62
Charruia Rusconi 1955F62
`--*C. annulata Rusconi 1955F62
Cyrtotheca Hicks 1872F62
`--*C. hamula Hicks 1872F62
Anzalia Termier & Termier 1947H75
`--*A. cerebriformis Termier & Termier 1947H75
Bovicornellum Howell 1934H62
`--*B. vermontense Howell 1934H62
Cestites Caster & Brooks 1956H75
`--*C. mirabilis Caster & Brooks 1956H75
Coelenteratella Korde 1959 [=Coelenterella (l. c.)]H75
`--*C. antiqua Korde 1959H75
Lenaella Korde 1959H75
`--*L. reticulata Korde 1959H75
Paramedusium Gürich 1930H62
`--*P. africanum Gürich 1930H62
Escumasia Nitecki & Solem 1973H75
`--*E. roryi Nitecki & Solem 1973H75
Tyrkanispongia Vologdin & Drozdova 1970G79
`--*T. tenua Vologdin & Drozdova 1970G79
Redkinia Sokolov 1976G79
`--*R. spinosa Sokolov 1976G79
SuvorovellidaeG79
|--Suvorovella Vologdin & Maslov 1960G79
| `--*S. aldanica Vologdin & Maslov 1960G79
`--Majella Vologdin & Maslov 1960G79
`--*M. verkhojanica Vologdin & Maslov 1960G79
Petalostroma Pflug 1973G79
`--*P. kuibis Pflug 1973G79
CupithecidaeWS93
|--Cupitheca Duan in Xing et al. 1984MP10
| `--C. manicae Duan 1983WS93
`--Actinotheca Xiao & Zhou 1984 non Cookson & Eisenack 1960 (ICBN)WS93, L95
|--*A. mirus He in Qian 1977L95
|--A. costellata Xiao & Zhou 1984WS93
`--A. dolioformis Xiao & Zhou 1984WS93
Acidocharacus Qin & Ding 1988MP10
Caveacus Landing 1995L95
`--*C. rectus Landing 1995L95
Leiperia gracileB88
Potamotrygonocotyle amazonensisB88
Ellisell Peel & Berg-Madsen 1988YK03
Arbusculites Murray 1831M65
FedomiaBJ17
CoronacollinaBJ17
Arumberia Glaessner & Wade 1975G79
`--*A. banksi Glaessner & Wade 1975G79
Gangtoucunia aspera Luo & Hu 1999SHB15
Scolethricella minorZS10
Microcalanus pygmaeusZS10
Pentagonistipes petaloidesMB12
Hagionella cultrataL04
Liangshanella rotundataL04
Dabashanella hemicyclicaL04
Pseudovendia charnwoodensisW96, EL11
Mialsemia semichatoviW96, EL11
Bonata [Bonatiidae]NS93
`--B. septata Fedonkin 1980NS93
Staurinidia crucicula Fedonkin 1985NS93
Cambromedusa furcula Willoughby & Robison 1979NS93
Brooksellidae [Protomedusae]NS93
|--Brooksella Walcott 1896NS93, H75 [incl. Laotira Walcott 1896H75]
| |--B. canyonensis Bassler 1941NS93, H75 [=Asterosoma canyonensisH75]
| `--B. silurica (von Huene 1904)NS93
`--Duodecimedusina King in Harrington & Moore 1955NS93, H75
|--*D. typica King in Harrington & Moore 1955H75
`--D. aegyptiaca Avnimelech 1966NS93
Paiutitubulitidae [Paiutiida]WS93
|--Cambrotubulites trisepta Tynan 1983WS93
`--PaiutitubulitesWS93
|--P. durhami Tynan 1983WS93
`--P. variabilis Tynan 1983WS93
Ancienta [Ancientidae]WS93
|--A. arborea Schallreuter 1981WS93
|--A. fortensis Ross 1967WS93
|--A. ohioensis Ross 1967WS93
|--A. pomerania Schallreuter 1981WS93
`--A. rossi Schallreuter 1981WS93
Konyrum [Konyriidae]WS93
`--K. varium Nazarov & Popov 1976WS93
ParacarinachitidaeWS93
|--Paracarinachites sinensis Qian & Jiang 1982 [incl. Luyanhaochiton spinus Yu 1984]WS93
`--Yangtzechiton elongatus Yu 1984WS93
Typhloesus [Typhloesidae]WS93
`--T. wellsi (Melton & Scott 1973)WS93
Cyrtochites pinnoides Qian 1983WS93
Deuteronectanebos papillorum Schram 1979WS93
Etacystis communis Nitecki & Schram 1976WS93
Portalia mira Walcott 1918WS93
Pyrgites mirabilis Yu 1984WS93
Stefania longula Grigor’eva 1982WS93
Tummulduria incompertya Missarzhevsky 1969WS93
Westgardia gigantea Rowland & Carlson 1983WS93
Nabaviella Mostler & Mosleh-Yazdi 1976CA06
Holoplicatella Clausen & Álvaro 2006CA06
`--*H. margarita Clausen & Álvaro 2006CA06
Wushichites minutus Qian & Xiao 1984 [incl. W. polyedrus Qian & Xiao 1984]CA06
Tumulduria Missarzhevsky 1969D78
Bronicella Sokolov 1973D78
`--B. podolicaEL11
Scheia tuberosaG31
Palaeoaplisina laminaeformisG31
Macrodus tenuistriatusG31
Zenobiella incarnataJ63
Odontoceras Serville 1833EH19
Aulozoon soliorumR22
Keretsa brutoniR22
Valdainia plumosaEL11
Ventogyrus chistyakovi Ivantsov & Grazhdankin 1997G14
Lobularia palmataR26
Traegaardhia distosolenidiaCK10
Nephelis octoculataW17
Metazoa [Agnotozoa, Animalia, Diploblastica, Enterozoa, Epitheliozoa, Gelatinosa, Lithophyta, Parahoxozoa, Paratrilobita, Parazoa, Petalonamae, Petalonamidae, Phytozoa, Proarticulata, Spongiaria, Vendiamorpha, Vendobionta, Vendozoa, Xenoconchia]BJ17
*Pararenicola huaiyuanensis Wang 1982 [incl. Paleorhynchus anhuiensis Wang 1982, Ruedemannella minuta Wang 1982, Paleolina tortuosa Wang 1982]SWZ86
*Type species of generic name indicated
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