Eleutherozoa

Sclerites of Protocaudina dulcis, from Boczarowski (2001).

Belongs within: Echinodermata.
Contains: Asteroidea, Ophiuroidea, Echinoidea, Holothuroidea.

The clade Eleutherozoa includes the free-living echinoderms, which have lost the stem of more basal lineages, as well as inverting the central body axis so that the mouth is generally ventral rather than dorsal. In the Asterozoa, sea stars and brittle stars, the post-larval body is comprised of a central disc with radiating appendages (arms). The Echinozoa lack such appendages and have an somewhat globular test (albeit with the overall shape modified in many subgroups) with the ambulacra arranged meridionally, radiating from the the mouth more or less towards the anus.

Synapomorphies (from Smith 1984): Larva with incipient processes (auricularia); larval mouth developed; hydropore opening a calcified body (madreporite); anus absent in adults (regained in some subgroups); adult free-living; radial water vessel tip associated with terminal plate, new ambulacral plates added adorally to terminal plate; tube feet arising from lateral branches of radial water vessel; articulating spines present; aboral surface subequal to oral surface or greatly reduced; ectoneural nerve plexus as primary motor coordination system; hyponeural sinuses present; polian vesicles present; Tiedemann's bodies present.

<==Eleutherozoa [Cryptosyringida]
    |  i. s.: Apostichopus japonicus GAS03
    |--Asterozoa [Stelleroidea] B01
    |    |  i. s.: Trichotaster Wright 1873 [=Trochitaster (l. c.)] SW66
    |    |           `--*T. plumiformis Wright 1873 SW66
    |    |--+--Asteroidea BH03
    |    |  `--Ophiuroidea BH03
    |    `--Somasteroidea [Goniactinida] BH03
    |         |  i. s.: Ophioxenikos Blake & Guensberg 1993 BH03
    |         |         Apullaster EL11
    |         |--Chinianaster Thoral 1935 [Chinianasteridae] SW66
    |         |    `--*C. levyi Thoral 1935 SW66
    |         |--Archegonaster Jaekel 1923 [Archegonasteridae] SW66
    |         |    `--*A. pentagonus Jaekel 1923 SW66
    |         |--Villebrunasteridae SW66
    |         |    |--*Ampullaster ubaghsi SW66
    |         |    `--Villebrunaster Spencer 1951 SW66
    |         |         `--*V. thorali Spencer 1951 SW66
    |         `--Archophiactinidae SW66
    |              |--Archophiactis Spencer 1925 SW66
    |              |    `--*A. grayae Spencer 1925 SW66
    |              |--Stuertzura Gregory 1897 SW66
    |              |    `--*S. brisingoides (Gregory 1889) [=Protaster brisingoides] SW66
    |              `--Lepidasterina Ruedemann 1916 SW66
    |                   `--*L. gracilis Ruedemann 1916 SW66
    `--Echinozoa B01
         |  i. s.: Astrocystites Whiteaves 1897 U78, F67 (see below for synonymy)
         |           `--*A. ottawaensis Whiteaves 1897 [=*Steganoblastus ottawaensis] F67
         |--Echinoidea M01
         `--+--Holothuroidea M01
            `--Ophiocistioidea [Ophiocista, Ophiocistia, Ophiocystia] M01
                 |  i. s.: Linguaserra Langer 1991 B01
                 |           `--*L. ligula Langer 1991 B01
                 |         Anguloserra thomasi Haude & Langenstrassen 1976 B01
                 |--Eucladia Woodward 1869 U66 [Eucladidae, Eucladiidae B01]
                 |    |--*E. johnsoni Woodward 1869 U66
                 |    `--E. beecheri Schuchert 1915 U66
                 |--Rhenosquama Richter 1930 [Rhenosquamidae] U66
                 |    `--*R. westfalica Richter 1930 U66
                 |--Volchovia Gekker 1938 [Volchoviidae] U66
                 |    |--*V. mobilis Gekker 1938 U66
                 |    `--V. norvegica U66
                 |--Sollasinidae B01
                 |    |--Gillocystis B01
                 |    |--Euthemon Sollas 1899 U66
                 |    |    `--*E. igerna Sollas 1899 U66
                 |    `--Sollasina Fedotov 1926 [incl. Cardioserra Romanek 1984] B01
                 |         |--*S. woodwardi (Sollas 1899) B01 [=Eucladia woodwardi U66]
                 |         |--S. minima (Romanek 1984) [=*Cardioserra minima] B01
                 |         `--S. westfalica (Richter 1930) B01
                 `--Rotasacciidae [Protocaudinidae] B01
                      |--Pararotasaccus Kozur & Mostler 1989 B01
                      |--Eriserra Boczarowski 2001 B01
                      |    `--*E. romaneki Boczarowski 2001 B01
                      |--Longiserra Boczarowski 2001 B01
                      |    `--*L. longa Boczarowski 2001 B01
                      |--Ornatoserra Boczarowski 2001 B01
                      |    `--*O. ovalis Boczarowski 2001 B01
                      |--Rotasaccus Haude & Langenstrassen 1976 B01
                      |    |--*R. dentifer Haude & Langenstrassen 1976 B01
                      |    |--R. haudei Boczarowski 2001 B01
                      |    `--R. praedentifer Boczarowski 2001 B01
                      |--Microantyx Kornicker & Imbrie 1958 B01
                      |    |--*M. permiana Kornicker & Imbrie 1958 B01
                      |    |--M. antyx FE66
                      |    |--M. botoni FE66
                      |    `--M. praedulcis Boczarowski 2001 B01
                      `--Protocaudina Croneis 1932 B01
                           |--*P. traquairii (Etheridge 1881) [=Cheirodota traquairii] B01
                           |--P. botoni (Gutschick 1959) B01
                           |--P. dulcis Boczarowski 2001 B01
                           |--P. mortenseni Deflandre-Rigaud 1946 FE66
                           |--P. paucispinosa Deflandre-Rigaud 1961 FE66
                           |--P. sosioensis (Kozur & Mostler 1989) B01
                           `--P. tarazi (Mostler & Rahimi-Yazd 1976) B01

Astrocystites Whiteaves 1897 U78, F67 [=Steganoblastus Whiteaves 1898 F67; Astrocystitidae, Edrioblastoidea, Pentacystida, Steganoblastidae]

*Type species of generic name indicated

REFERENCES

[BH03] Blake, D. B., & H. Hagdorn. 2003. The Asteroidea (Echniodermata) of the Muschelkalk (Middle Triassic of Germany). Paläontologische Zeitschrift 77 (1): 23–58.

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

[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.

[F67] Fay, R. O. 1967. Edrioblastoids. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt S. Echinodermata 1. General characters. Homalozoa—Crinozoa (except Crinoidea) vol. 1 pp. S289–S292. The Geological Society of America, Inc., and The University of Kansas: Lawrence (Kansas).

[FE66] Frizzell, D. L., & H. Exline. 1966. Holothuroidea—fossil record. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt U. Echinodermata 3 vol. 2 pp. U646–U672. The Geological Society of America, Inc., and The University of Kansas Press.

[GAS03] Gulbin, V. V., I. S. Arzamastsev & V. M. Shulkin. 2003. Ecological monitoring of the water area of Port Vostochnyi (Wrangel Bay) in the Sea of Japan (1995–2002). Russian Journal of Marine Biology 29 (5): 284–295.

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

Smith, A. B. 1984. Classification of the Echinodermata. Palaeontology 27 (3): 431-459.

[SW66] Spencer, W. K., & C. W. Wright. 1966. Asterozoans. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt U. Echinodermata 3 vol. 1 pp. U4–U107. The Geological Society of America, Inc., and The University of Kansas Press.

[U66] Ubaghs, G. 1966. Ophiocistoids. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt U. Echinodermata 3 vol. 1 pp. U174–U188. The Geological Society of America, Inc., and The University of Kansas Press.

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