Echinodermata

Specimen of Ctenocystis cf. utahensis, from here.

Belongs within: Deuterostomia.
Contains: Ankyroida, Cincta, Soluta, Helicoplacoidea, Cyclocystoidea, Blastozoa, Crinoidea, Eleutherozoa.

The Echinodermata are a diverse group of marine invertebrates characterised by the possession of an ultrastructurally distinct calcite exoskeleton (the stereom), a water vascular system (at least in living taxa) and, in most species, a secondary radial (usually pentamerous) symmetry. The phylogeny of echinoderms, of which many major lineages are extinct, is still hotly debated, and the (probably unwise) tree given below is drawn from a number of conflicting topologies. A primary contentious issue is the status of Palaeozoic taxa lacking a pentamerous organisation, such as the Stylophora and Ctenocystoidea. Some authors regard these taxa as diverging before the evolution of pentamery; others regard them as derived taxa that have secondarily lost this character.

Characters (from Ubaghs 1967, 'General characters of Echinodermata' Treatise on Invertebrate Paleontology pt S vol. 1): Marine, benthonic (or exceptionally pelagic) animals, living in an attached position or free, but never colonial. Enterocoelic, nonsegmented, coelomate, no differentiated head or brain; fundamentally bilaterally symmetrical, but modified by asymmetry introduced by atrophy of some organs of the right anterior side of the body and corresponding overdevelopment of organs of the left side; radial symmetry (typically pentamerous), secondarily imposed on larval asymmetry; no differentiated excretory apparatus. Endoskeleton formed of plates or distinct ossicles, composed of crystalline calcite deposited in organic mesenchymatous network displaying a reticulate microstructure and distinctive crystallographic properties. Water-vascular system of sacs and canals of coelomic nature opening outward in a pore and giving rise to numerous small projections on the surface of the body.

<==Echinodermata [Amphoridea, Carpoidea, Crinozoa, Homalozoa, Pelmatozoa, Taxiporitidae, Thecoidea]
    |--Stylophora [Cornuta, Cothurnocystidae] SCM04
    |    |  i. s.: Archaeocothurnus bifida L03
    |    |         Ponticulocarpus rushtoni L03
    |    |         Proscotiaecystis melchiori L03
    |    |--Ceratocystis Jaekel 1901 P97, U67a [Ceratocystidae]
    |    |    `--*C. perneri Jaekel 1901 U67a
    |    `--+--+--Prochauvelicystis semispinosa Daley 1992 P97, L03
    |       |  `--Chauvelicystis P97
    |       |       |--C. spinosa Ubaghs 1969 L03
    |       |       `--C. vizcainoi Daley 1992 L03
    |       `--+--+--Ankyroida P97
    |          |  `--Phyllocystis Thoral 1935 P97, U67a
    |          |       |--*P. blayaci Thoral 1935 U67a
    |          |       `--P. crassimarginata Thoral 1935 L03
    |          `--+--+--Galliaecystis P97
    |             |  `--Nevadaecystis Ubaghs 1967 P97, U67a
    |             |       `--*N. amaericana (Ubaghs 1963) [=Cothurnocystis americana] U67a
    |             `--+--Scotiaecystidae U67a
    |                |    |--Bohemiaecystis Caster in Ubaghs 1967 U67a
    |                |    |    `--*B. bouceki Caster in Ubaghs 1967 U67a
    |                |    `--Scotiaecystis Carter & Ubaghs in Ubaghs 1967 P97, U67a
    |                |         `--*S. curvata (Bather 1913) [=Cothurnocystis curvata] U67a
    |                `--+--Procothurnocystis P97
    |                   `--Cothurnocystis Bather 1913 P97, U67a
    |                        |--*C. elizae Bather 1913 U67a
    |                        |--C. bifida Ubaghs & Robison 1988 P99
    |                        |--C. fellinensis Ubaghs 1969 L03
    |                        `--C. primaeva U67a
    `--+--Ctenocystoidea M01
       |    |--Jugoszovia Dzik & Orłowski 1995 [Jugoszoviidae] D-A99
       |    |    `--J. archaeocyathoides Dzik & Orłowski 1995 D-A99
       |    `--Ctenocystidae D-A99
       |         |--Etoctenocystis Fatka & Kordule 1985 D-A99
       |         |    `--E. bohemica Fatka & Kordule 1985 D-A99
       |         `--Ctenocystis Robison & Sprinkle 1969 D-A99
       |              |--*C. utahensis Robison & Sprinkle 1969 SR78
       |              |--C. colodon Ubaghs & Robison 1988 D-A99
       |              |--C. jagoi Jell et al. 1985 D-A99
       |              `--C. smithi Ubaghs 1987 D-A99
       `--+--Cincta M01
          `--+--Soluta M01
             `--+--Arkarua [Pentaradialomorpha] M01
                |    `--A. adami EL11
                `--+--Helicoplacoidea M01
                   `--+--Camptostroma Ruedemann 1933 M01, D67 [Camptostromatoidea, Camptostromoidea]
                      |    `--*C. roddyi Ruedemann 1933 D67
                      `--+--Thecocystidae [Stromatocystitoidea] J18
                         |    |--Stromatocystites balticus M01, J18
                         |    |--Thecocystis J18
                         |    |--Cystaster J18
                         |    `--Cyathocystis J18
                         |         |--C. corallum Jaekel 1918 J18
                         |         `--C. plantinae J18
                         `--+--Edrioasteroidea U78
                            |    |  i. s.: Dinocystis J18
                            |    |         Cambraster EL11
                            |    |--Isophorida U78
                            |    `--Edrioaster M01 [Edrioasterida U78]
                            `--+--Cyclocystoidea M01
                               `--+--Blastozoa M01
                                  `--+--Crinoidea M01
                                     `--Eleutherozoa M01

Echinodermata incertae sedis:
  Xyloplax [Concentricycloidea, Concentricyclomorpha] B01
    `--X. medusiformis MH96
  Ophioplocus japonicus CGS00
  Agelacrinidae J18
    |--Hemicystites J18
    `--Agelacrinites lebouri J18
  Haplozoa U78
    |--Cymbionites Whitehouse 1941 [Cymbionitidae] U67b
    |    `--*C. craticula Whitehouse 1941 U67b
    `--Peridionites Whitehouse 1941 [Peridionitidae] U67b
         `--*P. navicula Whitehouse 1941 U67b
  Goniodiscus Müller & Troschel 1842 BR05
  Pichyceras Rusconi 1955 T64
    `--*P. jorusconii Rusconi 1955 T64
  Capsulina Seguenza 1880 LT64
    `--*C. loculicida Seguenza 1880 LT64
  Protocyclina Paalzow 1922 LT64
    `--*P. liassina Paalzow 1922 LT64

*Type species of generic name indicated

REFERENCES

[B01] Boczarowski, A. 2001. Isolated sclerites of Devonian non-pelmatozoan echinoderms. Palaeontologia Polonica 59: 1-219.

[BR05] Bouchet, P., J.-P. Rocroi, J. Frýda, B. Hausdorf, W. Ponder, Á. Valdés & A. Warén. 2005. Classification and nomenclator of gastropod families. Malacologia 47 (1-2): 1-397.

[CGS00] Cameron, C. B., J. R. Garey & B. J. Swalla. 2000. Evolution of the chordate body plan: New insights from phylogenetic analyses of deuterostome phyla. Proceedings of the National Academy of Sciences of the USA 97 (9): 4469-4474.

[D-A99] Domínguez-Alonso, P. 1999. The early evolution of echinoderms: the class Ctenocystoidea and its closest relatives revisited. In Echinoderm Research 1998 (M. D. Candia Carnevali & F. Bonasoro, eds) pp. 263-268. A. A. Balkema: Rotterdam.

[D67] Durham, J. W. 1967. Camptostromatoids. In Treatise on Invertebrate Paleontology pt. S. Echinodermata 1. General characters. Homalozoa-Crinozoa (except Crinoidea) (R. C. Moore, ed.) vol. 2 pp. S627-S631. The Geological Society of America, Inc., and The University of Kansas: Lawrence (Kansas).

[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.

[J18] Jaekel, O. 1918. Phylogenie und System der Pelmatozoen. Paläontologische Zeitschrift 3: 1-128.

[L03] Lefebvre, B. 2003. Funtional morphology of stylophoran echinoderms. Palaeontology 46 (3): 511-555.

[LT64] Loeblich, A. R., Jr & H. Tappan. 1964. Sarcodina: chiefly “thecamoebians” and Foraminiferida. In Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt. C. Protista 2, vol. 2. The Geological Society of America and The University of Kansas Press.

[MH96] Miller, S. A., & J. P. Harley. 1996. Zoology (3rd ed.) Wm. C. Brown Publishers: Dubuque (Iowa).

[M01] Mooi, R. 2001. Not all written in stone: Interdisciplinary syntheses in echinoderm paleontology. Canadian Journal of Zoology 79: 1209-1231.

[P97] Parsley, R. L. 1997. The echinoderm classes Stylophora and Homoiostelea: Non Calcichordata. Paleontological Society Papers 3: 225-248.

[P99] Parsley, R. L. 1999. The Cincta (Homostelea) as blastozoans. In Echinoderm Research 1998 (M. D. Candia Carnevali & F. Bonasoro, eds) pp. 369-375. A. A. Balkema: Rotterdam.

[SCM04] Shu, D.-G., S. Conway Morris, J. Han, Z.-F. Zhang & J.-N. Liu. 2004. Ancestral echinoderms from the Chengjiang deposits of China. Nature 430: 422-428.

[SR78] Sprinkle, J., & R. A. Robison. 1978. Addendum to subphylum Homalozoa: Ctenocystoids. In Treatise on Invertebrate Paleontology pt. T. Echinodermata 2. Crinoidea (R. C. Moore & C. Teichert, eds) vol. 3 pp. T998-T1002. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).

[T64] Teichert, C. 1964. Doubtful taxa. In Treatise on Invertebrate Paleontology pt. K. Mollusca 3. Cephalopoda – General Features – Endoceratoidea – Actinoceratoidea – Nautiloidea – Bactritoidea (R. C. Moore, ed.) pp. K484-K490. The Geological Society of America and the University of Kansas Press.

[U67a] Ubaghs, G. 1967a. Stylophora. In Treatise on Invertebrate Paleontology pt. S. Echinodermata 1. General characters. Homalozoa-Crinozoa (except Crinoidea) (R. C. Moore, ed.) vol. 2 pp. S495-S565. The Geological Society of America, Inc., and The University of Kansas: Lawrence (Kansas).

[U67b] Ubaghs, G. 1967b. Cymbionites and Peridionites – unclassified Middle Cambrian echinoderms. In Treatise on Invertebrate Paleontology pt. S. Echinodermata 1. General characters. Homalozoa-Crinozoa (except Crinoidea) (R. C. Moore, ed.) vol. 2 pp. S634-S637. The Geological Society of America, Inc., and The University of Kansas: Lawrence (Kansas).

[U78] Ubaghs, G. 1978. Classification of the echinoderms. In Treatise on Invertebrate Paleontology pt. T. Echinodermata 2. Crinoidea (R. C. Moore & C. Teichert, eds) vol. 1 p. T359-T367. The Geological Society of America, Inc.: Boulder (Colorado), and The University of Kansas: Lawrence (Kansas).