Trilobozoa

Paraconularia missouriensis, from here.

Belongs within: Medusozoa.
Contains: Anabaritida.

The Trilobozoa are a group of organisms of uncertain relationships known from the Ediacaran and lower Cambrian, characterised by the presence of three planes of symmetry or by the spiral rotation of three independent arm-like structures (Erwin et al. 2011). These include the Ediacaran Triradialomorpha, which were benthic, reclining forms of a superficially medusoid appearance.

Ivantsov & Fedonkin (2002) also suggested that the Conulariida, a group of sessile, pyramidal animals that survived to the Triassic, may be descended from the Trilobozoa. Conulariids possessed an external test supported by transverse rods of calcium phosphate. Though the majority of later conulariids have a fourfold symmetry in the manner of modern Scyphozoa, the Ediacaran Vendoconularia triradiata has a similar (albeit non-mineralised) test but with six faces.

Trilobozoa
    |--Triradialomorpha EL11
    |    |--Anfesta stankovskii EL11
    |    |--Pomoria corolliformis EL11
    |    |--Triforillonia costellae EL11
    |    |--Albumares Fedonkin in Keller & Fedonkin 1976 IF02, G79
    |    |    `--*A. brunsae Fedonkin in Keller & Fedonkin 1976 G79
    |    |--Skinnera Wade 1969 EL11, G79
    |    |    `--*S. brooksi Wade 1969 G79
    |    `--Tribrachidium Glaessner in Glaessner & Daily 1959 EL11, G79
    |         `--*T. heraldicum Glaessner in Glaessner & Daily 1959 G79
    `--+--Hallidaya Wade 1969 IF02, G79
       |    `--*H. brueri Wade 1969 G79
       `--+--Anabaritida IF02
          `--Conulata IF02
               |  i. s.: Vendoconularia Ivantsov & Fedonkin 2002 IF02
               |           `--*V. triradiata Ivantsov & Fedonkin 2002 IF02
               |--Emeiconularia [Carinachitidae, Carinachitiida] IF02
               |--Hexanguloconularida IF02
               `--Conulariida IF02
                    |--Palaenigma Walcott 1885 [=Tetradium Schmidt 1874 nec Dana 1846 nec Safford 1856] F62
                    |    `--*P. wrangeli (Schmidt 1874) [=*Tetradium wrangeli] F62
                    |--Hyolithoconularia Termier & Termier 1950 F62
                    |    `--*H. striata Termier & Termier 1950 F62
                    |--Conularia Miller in Sowerby 1821 KC60
                    |    |--C. bowningensis [incl. C. distincta Fletcher 1938] F71
                    |    |--C. chapmani Fletcher 1938 F71
                    |    |--C. expansa Fletcher 1938 F71
                    |    |--C. loculata IF02
                    |    |--C. mitchelli Fletcher 1938 F71
                    |    |--C. triangulata IF02
                    |    `--C. tulipa M79
                    `--Paraconularia F71
                         |--P. acutilirata (Fletcher 1938) [=Conularia acutilirata] F71
                         |--P. crenulata (Fletcher 1938) [=Conularia crenulata] F71
                         |--P. derwentensis [=Conularia derwentensis] F71
                         |--P. inornata (Dana 1849) [=Conularia inornata] F71
                         |--P. levigata [=Conularia levigata] F71
                         |--P. missouriensis IF02
                         |--P. nefarius F71
                         |--P. tenuistriata [=Conularia tenuistriata] F71
                         |--P. tuberculata (Fletcher 1938) [=Conularia tuberculata] F71
                         `--P. warthi [=Conularia warthi] F71

*Type species of generic name indicated

REFERENCES

[EL11] Erwin, D. H., M. Laflamme, S. M. Tweedt, E. A. Sperling, D. Pisani & K. J. Peterson. 2011. The Cambrian conundrum: early divergence and later ecological success in the early history of animals. Science 334: 1091–1097.

[F62] Fisher, D. W. 1962. Small conoidal shells of uncertain affinities. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt W. Miscellanea: Conodonts, Conoidal Shells of Uncertain Affinities, Worms, Trace Fossils and Problematica pp. W98–W143. Geological Society of America, and University of Kansas Press.

[F71] Fletcher, H. O. 1971. Catalogue of type specimens of fossils in the Australian Museum, Sydney. Australian Museum Memoir 13: 1–167.

[G79] Glaessner, M. F. 1979. Precambrian. In: Robison, R. A., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt A. Introduction. Fossilisation (Taphonomy), Biogeography and Biostratigraphy pp. A79–A118. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[IF02] Ivantsov, A. Yu., & M. A. Fedonkin. 2002. Conulariid-like fossil from the Vendian of Russia: a metazoan clade across the Proterozoic/Palaeozoic boundary. Palaeontology 45 (6): 1219–1229.

[KC60] Knight, J. B., L. R. Cox, A. M. Keen, R. L. Batten, E. L. Yochelson & R. Robertson. 1960. Gastropoda: systematic descriptions. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt I. Mollusca 1: Mollusca—General Features, Scaphopoda, Amphineura, Monoplacophora, Gastropoda—General Features, Archaeogastropoda and some (mainly Paleozoic) Caenogastropoda and Opisthobranchia pp. I169–I331. Geological Society of America, and University of Kansas Press.

[M79] Müller, A. H. 1979. Fossilization (taphonomy). In: Robison, R. A., & C. Teichert (eds) Treatise on Invertebrate Paleontology pt A. Introduction. Fossilisation (Taphonomy), Biogeography and Biostratigraphy pp. A2–A78. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).