Stylophora (Stylophorans)

The stylophorans are an extinct, possibly polyphylletic group allied to the echinoderms, comprising the cornutes and mitrates.It is synonymous with the subphylum Calcichordata. The general stylophoran body plan consists of a flattened theca and a single jointed appendage which extends from it. Stylophoran tests are composed of stereom calcite plates like an echinoderm, which has traditionally been the basis for assigning them to Echinodermata. However, they also lack the radial symmetry characteristic of most other echinoderms, with the earlier members of the group being flattened and asymmetrical, and the later ones closer to bilateral symmetry. In Mitrocystites and perhaps in other forms its stem does not end in an attachment organ, and the stem more likely served the organism as a tail for movement. Cothurnocystis is asymmetrical and boot-shaped, and Mitrocystites is bilaterally symmetrical and more streamlined. It has additionally been suggested that some or all of its members might have had gill slits like a chordate, and that their stems contained a notochord.This reconstruction leads to the alternative hypothesis that some or all of the stylophorans may have been ancestral to the chordate branch of the deuterostomes, rather than being within the echinoderms.

Source
http://en.wikipedia.org/wiki/Stylophora

Dalejocystis easteri	Prokop (1963), Pl. 84, fig. 2	RP16
Dalejocystis easteri	Prokop (1963), Pl. 84, fig. 1b	RP15
Destombesicarpus budili Lefebvre et al., 2021	Lefebvre et al. (2021), Pl.24, fig.d	OZ152
Diamphidiocystis regnaulti	Lefebvre et al. (2021), Fig.3b	OZ292
Diamphidiocystis regnaulti	Lefebvre et al. (2021), Fig.3e	OZ294
Diamphidiocystis regnaulti	Lefebvre et al. (2021), Fig.3d	OZ293
Diamphidiocystis regnaulti		LK19
Diamphidiocystis regnaulti	Lefebvre et al. (2021), Fig 10;13	OZ151
Diamphidiocystis regnaulti	Lefebvre et al. (2021), Fig.3a	OZ291
Diamphidiocystis regnaulti	Lefebvre et al. (2022, GSL), Figs.11b, 14f	LK18
Diamphidiocystis		OZ120
Diamphidiocystis		OZ121
Domfrontia milnerorum	Lefebvre et al. (2021), Figs. 21g,38d,39d	OZ154
Domfrontia milnerorum	Lefebvre et al. (2021), Fig. 21f, 38c, 39c	OZ153
Eumitrocystella		OZ122
Lagynocystites pyramidalis		JP1424
Lagynocystites pyramidalis		JP1423
Lagynocystites pyramidalis		JP595
Lagynocystites pyramidalis		KOS1777
Lagynocystites pyramidalis		JP1410

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Img. 85: Morphology of Stylophorans (after Ruta 2003)

Img. 85:

Virtual museum of the Czech Geological Survey, www.geology.cz, (C) Czech Geological Survey, 2011, v.0.99 [13.12.2011]