Ankyroida

Anatifopsis barrandei minuta, from Christophe Guillou.

Belongs within: Echinodermata.
Contains: Mitrocystitida.

The Ankyroida is a proposed clade of stylophoran echinoderms that combines the mitrates with various taxa previously included in the Cornuta. Ankyroids tend to have more symmetrical thecae than other stylophorans. In basal taxa, the theca bears a tesselate arrangement of small plates like that in non-ankyroid stylophorans; in derived taxa, this becomes replaced by a regular arrangement of fewer, larger plates. The major appendage (variously interpreted by different authors as a propulsive 'tail' or feeding arm) also bears a varying number of spinose, probably ventral projections that may have functioned to anchor the animal on the sediment surface.

Characters (from Parsley 1997): Theca and marginals symmetrical or near symmetrical; distal element of zygal not part of marginal series.

<==Ankyroida [Amygdalothecida, Lagynocystida, Mitrata]
    |  i. s.: Domfrontia L03
    |         Dalejocystis Prokop 1963 U67
    |           `--*D. casteri Prokop 1963 U67
    |--Amygdalotheca griffei P97, L03
    `--+--+--+--Reticulocarpos hanusi Jefferies & Prokop 1972 P97, L03
       |  |  `--Prokopicystis mergli Cripps 1989 P97, L03
       |  `--+--Milonicystis kerfornei P97, L03
       |     `--+--Mitrocystitida P97
       |        `--Nanocarpus P97 [incl. Juliaecarpus L03]
       |             |--N. dolambii Ubaghs 1991 L03
       |             `--N. milnerorum (Ruta 1999) L03
       `--+--Lyricocarpus P97
          `--+--Beryllia P97
             `--+--Chinianocarpos Ubaghs 1961 P97, U67
                |    `--*C. thorali Ubaghs 1961 U67
                `--Peltocystida L03
                     |--Peltocystis Thoral 1935 P97, U67 [Peltocystidae]
                     |    `--*P. cornuta Thoral 1935 U67
                     `--+--Jaekelocarpus oklahomensis P97, L03
                        `--Kirkocystidae [Kirkocystinae] U67
                             |--Balanocystites Barrande 1887 U67 (see below for synonymy)
                             |    |--*B. lagenula Barrande 1887 U67
                             |    `--B. primus (Barrande 1872) L03
                             |--Anatiferocystis Chauvel 1941 P97, U67 [incl. Kirkocystis Bassler 1950 U67]
                             |    |--*A. barrandei Chauvel 1941 U67
                             |    |--A. papillata (Bassler 1943) [=Enoploura papillata, *Kirkocystis papillata] U67
                             |    `--A. punctata U67
                             `--Anatifopsis [incl. Guichenocarpos] L03
                                  |--A. ancora Domínguez & Gutiérrez-Marco 1990 L03
                                  |--A. barrandei L03
                                  |    |--A. b. barrandei L03
                                  |    `--A. b. minuta (Chauvel 1941) L03
                                  |--A. papillata (Bassler 1943) L03
                                  `--A. trapeziiformis Thoral 1935 L03

Balanocystites Barrande 1887 U67 [=Balanocystis Haeckel 1896 K67; incl. Sagittacystis L03]

*Type species of generic name indicated

REFERENCES

[K67] Kesling, R. V. 1967. Cystoids. In Treatise on Invertebrate Paleontology pt. S. Echinodermata 1. General characters. Homalozoa-Crinozoa (except Crinoidea) (R. C. Moore, ed.) vol. 1 pp. S85-S267. The Geological Society of America, Inc., and The University of Kansas: Lawrence (Kansas).

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

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

[U67] Ubaghs, G. 1967. 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).