Spinulosacea

Apical view of Baliactis sp., copyright Ru Smith.

Belongs within: Neoasteroidea.
Contains: Asterinidae, Echinasteridae, Solasteridae, Pterasteridae.

The Spinulosacea is a lineage of asteroids potentially supported by the absence of a mouth and a rudimentary gut in the larva, more or less asymmetrical coelomic sac formation in early development, and terminals that originate from the fusion of many calcification centres (Blake 1987). Adult forms have large, spade- or ploughshare-shaped mouth angles plates and wide ambulacral furrows in the Velatida, whereas the Spinulosida have small mouth-angle plates and narrow ambulacral furrows (Spencer & Wright 1966, as Eugnathina and Leptognathina).

Characters (from Blake 1987): Body shape thickened, with discs large or small, arms columnar or tapering, interbrachial angles often acute; area about mouth not depressed. Marginals, abactinals, actinals differentiated or not, ossicles generally relatively small; encrusting ossicles in form of spinelets, reduced in some taxa; pedicellariae always lacking. Madreporite near disc centre, usually small. Abactinals generally closely spaced, paxilliform or flattened; in early ontogeny, abactinals large in number without calycinal ring, in adults, calycinals range from undifferentiated to clearly defined. Terminals small. Marginals commonly in two series but only one or neither series differentiated in various taxa; almost always cryptozonate where differentiated. If multiple actinal rows present, longest row adjacent to adambulacrals. Oral frame, ambulacral column protected by thickened dermal tissues or not, not unusually protected by skeletal armour; oral frame dominated by oral ossicles. Ambulacral column rarely compressed, adoral carina lacking. Superambulacrals lacking, interbrachial septa reinforced with ossicles. Papulae generally widely distributed; tube feet almost always in two rows, suckered discs present but lacking spicules. In development, bipinnaria not known to occur alone, coelomic sac formation more or less asymmetrical with left somatocoel forming from posterior part of archenteron; larval mouth absent, larval gut rudimentary; terminals arising by fusion of many calcification centres.

<==Spinulosacea
    |--Spinulosida [Leptognathina, Spinulosa] BH03
    |    |--Asterinidae MG-H11
    |    |--Echinasteridae BH03
    |    |--Acanthaster Gervais 1841 (see below for synonymy) SW66
    |    |    `--A. planci (Linnaeus 1758) [=Asterias planci; incl. *Ac. echinus Gervais 1841] SW66
    |    |--Valvasteridae [Valvasterinae] SW66
    |    |    |--Valvaster Perrier 1876 SW66
    |    |    |    `--*V. striatus (Lamarck 1816) [=Asterias striata] SW66
    |    |    `--Diclidaster de Loriol 1897 SW66
    |    |         `--*D. gevreyi de Loriol 1897 SW66
    |    `--Ganeriidae [Cryasteridae] SW66
    |         |--Ganeria Gray 1847 SW66
    |         |    `--*G. falklandica Gray 1847 SW66
    |         |--Aleutiaster Clark 1939 SW66
    |         |    `--*A. schafferi Clark 1939 SW66
    |         |--Cycethra Bell 1881 [incl. Lebrunaster Perrier 1891] SW66
    |         |    `--C. verrucosa (Philippi 1857) [=Goniodiscus verrucosus; incl. *C. simplex Bell 1881] SW66
    |         |--Leilaster Clark 1938 SW66
    |         |    `--*L. radians (Perrier 1881) [=Korethraster radians] SW66
    |         |--Magdalenaster Koehler 1907 SW66
    |         |    `--*M. arcticus Koehler 1907 SW66
    |         |--Perknaster Sladen 1889 [incl. Cribellopsis Koehler 1917, Cryaster Koehler 1906] SW66
    |         |    `--*P. fuscus Sladen 1889 SW66
    |         |--Scotiaster Koehler 1908 SW66
    |         |    `--*S. inornatus Koehler 1908 SW66
    |         `--Tarachaster Fisher 1913 SW66
    |              `--*T. tenuis Fisher 1913 SW66
    `--Velatida [Eugnathina, Velata] BH03
         |--Caymanostellidae FR02
         |--Solasteridae WOR04
         |--Pterasteridae SW66
         |--Lepyriactis Spencer 1927 [Lepyriactinidae] SW66
         |    `--*L. nudus Spencer 1927 SW66
         |--Schuchertia Gregory 1899 [incl. Trentonaster Stürtz 1900; Schuchertiidae] SW66
         |    |--*S. stellata (Billings 1858) [=Palasterina stellata] SW66
         |    `--S. wenlocki SW66
         |--Tropidasteridae SW66
         |    |--Tropidaster Forbes 1850 SW66
         |    |    `--*T. pectinatus Forbes 1850 SW66
         |    `--Plumaster Wright 1861 SW66
         |         `--*P. ophiuroides Wright 1861 SW66
         |--Helianthasteridae SW66
         |    |--Helianthaster Roemer 1863 SW66
         |    |    `--*H. rhenanus Roemer 1863 SW66
         |    |--Echinasterella Stürtz 1890 SW66
         |    |    `--*E. sladeni Stürtz 1890 SW66
         |    `--Hystrigaster Lehmann 1957 SW66
         |         `--*H. horridus Lehmann 1957 SW66
         |--Taeniactinidae SW66
         |    |--Taeniactis Spencer 1927 SW66
         |    |    `--*T. wenlocki Spencer 1927 SW66
         |    |--Lepidasterella Schuchert 1914 SW66
         |    |    `--L. gyalum (Clarke 1908) [=Helianthaster gyalum; incl. *L. babcocki Schuchert 1914] SW66
         |    `--Baliactis Spencer 1922 [incl. Leioactis Lehmann 1957, Palaeactis Lehmann 1957] SW66
         |         |--*B. ordovicus Spencer 1922 SW66
         |         `--B. devonicus SW66
         |--Pythonasteridae SW66
         |    |--Pythonaster Sladen 1889 [Pythonasterinae] SW66
         |    |    `--*P. murrayi Sladen 1889 SW66
         |    `--Myxasterinae SW66
         |         |--Myxaster Perrier 1885 SW66
         |         |    `--*M. sol Perrier 1885 SW66
         |         `--Asthenactis Fisher 1906 SW66
         |              `--*A. papyraceus Fisher 1906 SW66
         `--Korethrasteridae SW66
              |--Korethraster Thomson 1873 SW66
              |    `--*K. hispidus Thomson 1873 SW66
              |--Anareaster Fell & Clark 1959 SW66
              |    `--*A. ganymede Fell & Clark 1959 SW66
              |--Peribolaster Sladen 1889 SW66
              |    `--*P. folliculatus Sladen 1889 SW66
              `--Remaster Perrier 1894 SW66
                   `--*R. palmatus (Perrier 1894) [=Korethraster (*Remaster) palmatus] SW66

Acanthaster Gervais 1841 [=Echinaster Gray 1840 non Müller & Troschel 1840; Acanthasteridae, Echinasterina] SW66

*Type species of generic name indicated

REFERENCES

Blake, D. B. 1987. A classification and phylogeny of post-Palaeozoic sea stars (Asteroidea: Echinodermata). Journal of Natural History 21 (2): 481-528.

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

[FR02] Fujita, T., & F. W. E. Rowe. 2002. Podosphaerasteridae fam. nov. (Echinodermata: Asteroidea: Valvatida), with a new species, Podosphaeraster toyoshiomaruae, from southern Japan. Species Diversity 7: 317–332.

[MG-H11] McEnnulty, F. R., K. L. Gowlett-Holmes, A. Williams, F. Althaus, J. Fromont, G. C. B. Poore, T. D. O’Hara, L. Marsh, P. Kott, S. Slack-Smith, P. Alderslade & M. V. Kitahara. 2011. The deepwater megabenthic invertebrates on the western continental margin of Australia (100–1100 m depths): composition, distribution and novelty. Records of the Western Australian Museum Supplement 80: 1–191.

[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.

[WOR04] Waters, J. M., P. M. O’Loughlin & M. S. Roy. 2004. Molecular systematics of some Indo-Pacific asterinids (Echinodermata, Asteroidea): does taxonomy reflect phylogeny? Molecular Phylogenetics and Evolution 30: 872–878.