taxonID	type	description	language	source
467887FDC3303A66FDD782F564BFF8FD.taxon	diagnosis	DIAGNOSIS. — Overall form low arched; outline ranging from subpentagonal with arms broad, more abruptly tapering, to outline substellate, arms triangular, elongate, more gradually tapering. Abactinals small, individually irregular but aboral surface in total uniform. Abactinals divisible into three types: abactinals delicate, multiradiate, arrangement reticulate; abactinals closely fitted small platelets; enlarged primary abactinals absent, ossicles limited to granules. Abactinals not aligned in rows, carinal, centrale, and aboral ring differentiation unknown. Madreporite recognized in three genera. Ambital frameworks varied, ranging from complexly arranged tiny platelets to single well-defined abutted series. Axial positioning across arm midline irregular, locally clearly offset to nearly opposite. Axials not permanently vaulted to form a furrow, but arm and disk capable of facultative flexure as to yield temporary furrow-like configurations. Axials nearly equidimensional, form differing among genera. Axial radial water vascular channel large, closed or nearly closed over water-vascular tissues in most genera. Transverse water-vascular channel ill-defined. Transverse ridge generally narrow, podial basins large, deep in most genera. Mouth frame ossicles relatively small, differentiation from more distal axials comparatively limited. Mouth-angle ossicles upright; small spinelets can occur; podial basin of adjacent axial aligned with those of more distal axials. Axillary (odontophore) not recognized. Terminal ossicle problematic, not definitively recognized. Linear, transverse series of proportionately small rod-like ossicles (“ virgals ”, the single series a “ virgalium ”, plural “ virgalia ”) radiate abradially from each axial, the first of the series more (e. g. Archegonaster) or less (e. g. Chinianaster) clearly differentiated from the remainder of the series. Virgalia occupy the interspace between ambital framework and axials thereby occupying the oral disk plane: actinal ossicles not recognized. Virgalium in life capable of some rotation about the longitudinal axis, virgalia capable of coordinated series deflection in the body plane. Virgalia thought to be lacking proximally from one genus. Accessories limited to relatively small spinelets and granules.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3303A67FC7D85BF614DFD31.taxon	type_taxon	TYPE GENUS. — Chinianaster Thoral, 1935.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3303A67FC7D85BF614DFD31.taxon	diagnosis	DIAGNOSIS. — Abactinal skeleton well-developed, consisting of many small, irregular but uniform ossicles. Ambital framework varied among genera, ossicles proportionately small, series well defined but ossicular arrangement irregular, varying among genera. Axials approximately equidimensional to rectangular; localized podial pores possibly occurring in two genera. Water-vascular channel skeletally closed orally. Virgalia reaching mouth frame. First virgal at most weakly differentiated.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3313A65FEE6879E623AF8A6.taxon	description	(Figs 1 A; 2; 3)	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3313A65FEE6879E623AF8A6.taxon	materials_examined	TYPE MATERIAL. — Lectotype. France • 1 specimen (specimen distorted, arm radii approximately 25 to 30 mm); Hérault, Saint-Chinian; Saint-Chinian Formation; Euloma filacovi Zone, late Tremadocian (Early Ordovician); Villebrun leg.; UCBL-FSL 168691 (Figs 2 A 1 - 4; 3 A). REFERRED SPECIMENS. — Eight specimens (UCBL-FSL 711093 [FSL 1879 553 of Dean Shackleton 2005], UCBL-FSL 711094 [FSL 1879 558 of Dean Shackleton 2005], UCBL-FSL 711095 [FSL 1879 563 of Dean Shackleton 2005], UCBL-FSL 712002 - 712004, UCBL-FSL 712090, UCBL-FSL 713577. Questionable, four more specimens (MBB-GG 20, MBB-GG 23, UCBL-FSL 712017, UCBL-FSL 713576). Assignment of two more specimens is problematic (MBB-GG 2, MBB-GG 18).	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3313A65FEE6879E623AF8A6.taxon	biology_ecology	TYPE LOCALITY AND HORIZON. — Saint-Chinian Formation, Early Ordovician (late Tremadocian); Saint-Chinian (Hérault), Montagne Noire, France.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3313A65FEE6879E623AF8A6.taxon	diagnosis	DIAGNOSIS. — Abactinals moderately robust, arrangement quite closely reticular (Fig. 2 A). Ambital framework ossicles tiny, plate-like; arrangement complex, series as preserved ill-defined, irregular (Fig. 2 B-D). Axials in aboral view shield-like, successive axials overlapping (Fig. 2 A). In oral view, compound axials not recognized. MAO not bearing an enlarged flange-like aboral process. Where not eroded, radial-water vascular channel enclosed at arm axis by an enclosing skeletal arch (Figs 2 C, E; 3 B, E). Adaxials moderately large, thin, broad surface longitudinally grooved, groove broad (Figs 2 E; 3 C).	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3313A65FEE6879E623AF8A6.taxon	description	DESCRIPTION Overall form in life low-arched, outline subpentagonal; arms broad, triangular, taper gradual. Abactinals spiculate, multiradiate, rod-like abactinals likely developed; abactinal arrangement open hexagonal reticular. Madreporite on oral surface offset from MAO, surface texture granular (Figs 2 C; 3 A, B). Ambital framework a continuous well-defined but irregular necklace of tiny platelets; ambital framework not deflected toward mouth frame to form a gap or cleft (Fig. 2 B-D). In aboral aspect, axials shield-like, surface curved, sequential axials overlapping, axial series longitudinally grooved approximately at position of abradial margin of podial basins; proximal axials with possible podial pore (Fig. 2 A, F). In oral aspect, where preserved (generally distally), radial water-vascular channel oral surface closed by shield-like skeletal arch (Figs 2 C, E; 3 B); where shield eroded (generally proximally) and axial series dilated, axials appearing approximately double-bilateral along and normal to transverse ridge; podial basin boundary medial; abradial margin concave. MAO proportionately small, appearing plate-like where directed toward mouth, rounded where deflected toward interior; lateral margins concave for tube foot; differentiation of circumoral appearing limited (Fig. 3 E). Virgalia abutting abradial terminus of axial transverse ridge, virgalia reaching mouth frame (Figs 2 B; 3 B, C, E). Virgals relatively thin, rectangular, planar, grooved, termini expanded; virgals when rotated to exposed broad surface potentially robust enough as to have formed a continuous platform at least where deflected distally. First virgals less elongate than more lateral virgals, otherwise similar. Virgal accessories, if any, small, granular.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3313A65FEE6879E623AF8A6.taxon	discussion	REMARKS The concept of Thoralaster Dean Shackleton 2005, was based on a part of the Chinianaster type suite, see under that genus. Shield-like overlapping axials and flat, rectangular adaxials provide guides to the recognition of Chinianaster. Although uncommonly clearly preserved, an ambital framework of fine platelets is shared only with Thoralaster. Dean Shackleton (2005: 68 R), however, posited presence of robust marginals in Chinianaster, some a “ large spike ”. The interpretation appears to have been based on her figure 5 B (p. 40), the apparent interval illustrated here (Fig. 2 F) in which ossicles are displaced and enlarged “ spikes ” are found at the arm tip. Spike identity is uncertain but more proximal ossicles argue terminal ossicles of virgalia, the ambital necklace all but lost from this specimen (Fig. 2 F). A single ossicle at the arm tip of a Chinianaster or near- Chinianaster specimen (Fig. 14 H) suggests a spike-like terminal. Dean Shackleton (2005) interpreted virgalia as lacking at the mouth frame of Chinianaster; although largely disrupted, remnants of virgalia are common, including in the lectotype (Fig. 2 C, D).	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3313A67FEE186F9611DFAC5.taxon	diagnosis	DIAGNOSIS. — As for Chinianaster levyi, the type and only recognized species.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3313A67FF2380FB624AFB23.taxon	discussion	Chinianasteridae Spencer, 1951, here recognized at the subfamily level for Chinianaster, Cantabrigiaster, and Thoralaster.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3313A67FF2380FB624AFB23.taxon	type_taxon	TYPE GENUS. — Chinianaster Thoral, 1935.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3313A67FF2380FB624AFB23.taxon	diagnosis	DIAGNOSIS. — Subpentagonal Chinianasteridae. Abactinals spiculate, arrangement reticulate. Ambital framework ossicles tiny, granular or plate-like; overall arrangement thought irregular. Radial water vascular canal large, skeletally delicate, closed orally, where closure was diagenetically lost abradial portion of ossicle doubly bilateral at midpoint of transverse ridge. Podial basin boundary approximately medial, basin shared equally by successive axials. Adradial adaxials weakly differentiated, virgalia relatively elongate.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3333A65FEBE857F6402F998.taxon	type_taxon	TYPE SPECIES. — Cantabrigiaster fezouataensis Hunter & Ortega-Hernández, 2021.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3333A65FEBE857F6402F998.taxon	diagnosis	DIAGNOSIS. — As for Cantabrigiaster fezouataensis, the type and only recognized species.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3333A60FC3E845F6485FC05.taxon	description	(Figs 4; 5)	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3333A60FC3E845F6485FC05.taxon	materials_examined	TYPE MATERIAL. — Holotype. Morocco • 1 specimen (only oral surface, good preservation of ossicular detail; arm radius R 27 mm; disk radius r 18 mm; both measurements and especially that of the latter extended by sediment compaction); Central Anti-Atlas, Ternata plain (north of Zagora); Sagenograptus murrayi Zone, late Tremadocian (Early Ordovician); 2003, Van Roy leg.; UCBL-FSL 424961 (Fig. 4 A-D). REFERRED SPECIMENS. — 34 specimens (MHNN. P. 045596, PRIP 20026 - 20027, PRIP 20028.1 - 6; PRIP 20029.1 - 2, PRIP 20030.1 - 2, UCBL-FSL 424962, UCBL-FSL 711937 - 711939, UCBL-FSL 711945 - 711946, YPM IP 535545 - 535559).	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3333A60FC3E845F6485FC05.taxon	distribution	TYPE LOCALITY AND HORIZON. — Fezouata Formation, Early Ordovician (late Tremadocian); Ternata plain, Zagora area, Anti-Atlas, Morocco.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3333A60FC3E845F6485FC05.taxon	diagnosis	DIAGNOSIS. — Abactinal arrangement open reticular (Figs 4 F; 5 A, C, D). Ambital framework ossicles small, granular, complexly overlapping but closely abutted as to form a clearly defined series (Figs 4 E; 5 A, D, E). Axials in aboral view rectangular, successive axials abutted, not notably overlapping (Fig. 5 A). In oral view, compound axials can occur at mouth frame (Fig. 4 C). Radial water-vascular channel narrowly enclosed at arm axis (Figs 4 A, C; 5 A). Adaxials strongly robust, rectangular, longitudinal ridges well-defined, adjacent abutted virgalia forming a transverse well-defined groove, abutted virgalia forming a distinct platform (Figs 4 A, B; 5 D, E).	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3333A60FC3E845F6485FC05.taxon	description	DESCRIPTION Overall form in life low-arched, outline subpentagonal; arms broad, short, triangular. Abactinals rod-like; multiradiate abactinals not identified. Only identified madreporite (Fig. 5 A, B) aboral, surface texture granular, madreporite offset from central area of disk. Ambital framework well-defined, marginal series forming a continuous pentagonal outline extending around the arm tip, series not deflected toward mouth frame to form gap or cleft. Ambital framework ossicles small, numerous, equidimensional, granular to weakly elongate; ossicles overlapping, not differentiated as to suggest inferomarginals and superomarginals. In aboral aspect, axials nearly paired or slightly offset across arm midline, axial outline nearly square, sequential axials abutted; axial series (only where better preserved?) appearing longitudinally grooved. In oral aspect, axial outline approximately rectangular, water vascular channel large, enclosed. Axial transverse ridge narrow, axial approximately doubly bilateral at midpoint of transverse ridge, podial basin large, equally shared by subsequent axials, transverse ridge flared abradially to form concave seat for virgalium. Compound axial can occur at mouth frame. Terminal not recognized. First virgals smaller than but similar to more abradial; all virgals robust, rectangular, bearing a medial ridge and lateral groove shared by adjacent virgalia, ossicular boundaries approximately medial in groove. As typically preserved, adjacent virgalia deflected distally as to form a pavement. Accessories not clearly identified, some circular pustules and circular depressions might favor accessories.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3333A60FC3E845F6485FC05.taxon	discussion	REMARKS A posited absence of an ambital framework was foundational to the recognition of Cantabrigiaster fezouataensis, and putative absence essential to Cantabrigiaster assignment to a basal position within Somasteroidea. Presence of an ambital framework similar to that of Villebrunaster was documented in the holotype and other specimens of the type suite, and with emphasis on the framework, Cantabrigiaster was synonymized with Villebrunaster (Blake & Hotchkiss 2022). Herein, axial and adaxial expressions are argued as providing essential guides to asterozoan affinities (e. g. Blake 2013, 2018, 2024; Blake & Guensburg 2015; Glass et al. 2024), the differences between Cantabrigiaster and other somasteroids calling for generic recognition. Most distinctive, the robust adaxials of Cantabrigiaster differ from those of other somasteroid genera in both form and arrangement, with adjacent virgalia abutted laterally to form a robust platform. The ambital framework of Cantabrigiaster differs from those of Chinianaster, Villebrunaster, and Ampullaster in ossicular shape but not in overall series configuration. Surface texture of the madreporite (Fig. 5 A, B) is similar to that of Chinianaster (Fig. 3 A, B) although the two differ in madreporite positioning. Axial series offset and disruption of more proximal abactinals of the only Cantabrigiaster example exhibiting a madreporite indicate some displacement accompanied preservation, the present positioning therefore of unknown general significance.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3363A60FC7A81D863F3FB6E.taxon	type_taxon	TYPE SPECIES. — Thoralaster spiculiformis Dean Shackleton, 2005.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3363A60FC7A81D863F3FB6E.taxon	diagnosis	DIAGNOSIS. — As for Thoralaster spiculiformis, the type and only recognized species.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3363A6CFC95873E6200FA07.taxon	description	(Figs 1 B; 6 - 8)	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3363A6CFC95873E6200FA07.taxon	materials_examined	TYPE MATERIAL. — Holotype. France • 1 specimen (part and counterpart); Hérault, Saint-Chinian, La Croix-Rouge; Euloma filacovi Zone, late Tremadocian (Early Ordovician); 1953, Thoral leg.; UCBL-FSL 168697 (“ ES 1 ” of Dean Shackleton 2005); (Fig. 6 A 1 - 6). Paratype. France • 1 specimen; Hérault, Saint-Chinian; Euloma filacovi Zone, late Tremadocian (Early Ordovician); 1879, Lignières leg.; UCBL-FSL 711096 (“ FSL 1879 564 ” of Dean Shackleton 2005) (Fig. 7 B). REFERRED SPECIMENS. — Five specimens (UCBL-FSL 168690, UCBL-FSL 424943, UCBL-FSL 712005, MNHN. F. A 90271, MNHN. F. A 97739).	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3363A6CFC95873E6200FA07.taxon	distribution	TYPE LOCALITY AND HORIZON. — Saint-Chinian Formation, Early Ordovician (late Tremadocian); La Croix-Rouge, E of Saint-Chinian (Hérault), Montagne Noire, France.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3363A6CFC95873E6200FA07.taxon	diagnosis	DIAGNOSIS. — Abactinals delicate, arrangement open reticular (Fig. 7 A-C). Ambital framework ossicles tiny, plate-like, arrangement complex, series as preserved ill-defined, irregular (Figs 6 D-F; 7 A, C, E, F). Radial-water vascular channel narrowly enclosed at arm axis (Fig. 8 D, distal). In oral view, compound axials recognized near mouth frame (Figs 1 B; 6 A-C; 8 D). MAO bearing an enlarged flange-like aboral process (Figs 7 A, C; 8 A, C, E). Adaxials very delicate, rodlike, longitudinal groove narrow (Figs 1 B; 6 B, F; 7 A, C; 8 B).	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3363A6CFC95873E6200FA07.taxon	description	DESCRIPTION Overall form low-arched, outline substellate, arm outline in life thought to be triangular, moderately abruptly tapering. Abactinals delicate, spiculate, configuration open hexagonal reticular. Madreporite unknown. Ambital framework forming a continuous, well-defined, irregular necklace of tiny platelets, series not deflected toward mouth frame to form a gap or cleft. In aboral aspect, axial ossicles shield-like, sequential ossicles weakly overlapping (Figs 6 F; 7 A-C; 8 A, C, E), axial series longitudinally weakly grooved (Fig. 8 A). In oral aspect, radial water vascular channel closed (near arm tips, Figs 6 A; 7 A; 8 D, F). Some axials compound, i. e., bearing more than a portion of a podial basin on each side of the transverse ridge (Figs 1 B; 6 A, C; 8 D); non-compound axials appearing approximately double-bilateral along and normal to the transverse ridge; podial basin boundary medial, abradial axial margin concave. Mouth-angle ossicle transverse ridges converge abradially in an “ A ” - frame-like pattern (Fig. 8 D). Ossicle immediately adjacent to MAO (i. e., circumoral?) strongly flared as to yield an appearance suggestive of an open bivalve (Figs 7 A, C; 8 A, C, E). First subsequent axial similar to those of remainder of series, podial basin aligned with those of subsequent axials (Figs 7 D, E; 8 D, F). Virgalia abutting abradial terminus of axial transverse ridge, concentration of debris arguing virgalia reached mouth frame (Figs 6 A; 7 D; 8 A, B). Virgals proportionately very small, delicate, rod-like, grooved longitudinally, termini weakly expanded; first virgals short, otherwise similar to more lateral virgals. Virgalia too delicate to have formed an abutted platform. Some adjacent virgalia termini abutted abradially to support an enlarged, attenuated, distal “ radiole ” (Fig. 6 B, D, F). Virgal accessories small, plate-like to granular (Figs 1 B; 6 B, D, F).	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3363A6CFC95873E6200FA07.taxon	discussion	REMARKS The concept of Thoralaster was based on a few specimens taken from the type suite of Chinianaster (Dean Shackleton 2005); additional specimens are included here. The clearest criterion for specimen inclusion is presence of an enlarged, flanged surface suggestive of an open bivalve in the mouth frame, it most readily viewed in aboral aspect. Because variously preserved among specimens, it is unclear whether the flange is a part of the MAO or a separate ossicle, as is suggested by discontinuities (Figs 7 C; 8 C), the flange then either the circumoral or a supernumerary Additional generic criteria include presence of proportionately large, delicate axials, some compound in that the ossicle bears more than a partial podial basin on each side of the transverse ridge. Adaxials are very slender and rod-like. Perhaps suggesting structural integrity, most arm tips of Thoralaster held together during diagenesis, the axial series on the sides of the arm as preserved more (Figs 6 A; 7 A) or less (Fig. 8 A) strongly diverging toward the disk. Although recognized only in a single arm interval and thereby potentially indicative of a transitional state, positioning and regularity of expression of apparent openings suggest podial pores (Fig. 8 H). As compared to other somasteroid genera, overall construction of Thoralaster was somewhat delicate.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33A3A6CFC5C83BA63D7FDC8.taxon	type_taxon	TYPE SPECIES. — Villebrunaster thorali Spencer, 1951.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33A3A6CFC5C83BA63D7FDC8.taxon	diagnosis	DIAGNOSIS. — As for Villebrunaster thorali, the type and only known species.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33A3A6CFF2787DE6454FEF8.taxon	type_taxon	TYPE GENUS. — Villebrunaster Spencer, 1951.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33A3A6CFF2787DE6454FEF8.taxon	diagnosis	DIAGNOSIS. — Subpentagonal Chinianasteridae. Abactinals spiculate, arrangement reticulate. Ambital framework ossicles granular to somewhat elongate, overall arrangement somewhat irregular, ossicles overlapping. Radial water-vascular channel large, cylindrical, robust; axials asymmetrical. Podial basin on proximal side of transverse ridge. Adradial adaxials complexly differentiated, virgalia relatively elongate.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33A3A6CFF2787DE6454FEF8.taxon	discussion	REMARKS The Villebrunasterinae is separated from both the Chiniasterinae and the Ophioxenikosinae n. subfam. based on axial and adradial virgal differentiation, the Ophioxenikosinae n. subfam. further differing in form, abactinal, and ambital framework expressions. The Villebrunasterinae and Chiniasterinae earlier were recognized at the familial level (Fell 1963 b; Spencer & Wright 1966).	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33A3A68FC5680BB6295FBC5.taxon	description	(Figs 9 - 12)	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33A3A68FC5680BB6295FBC5.taxon	materials_examined	TYPE MATERIAL. — Holotype. France • 1 specimen (individual with five arms preserved; in the same concretion as paratype UCBL-FSL 168692 a. 2, see below); Hérault, Saint-Chinian, La Croix-Rouge; Euloma filacovi Zone, late Tremadocian (Early Ordovician); 1953, Thoral leg.; UCBL-FSL 168692 a. 1 (Fig. 9 A, C-E). Paratype. France • 1 specimen (only two arms preserved; part and counterpart with different registration numbers, see below); Hérault, Saint-Chinian, La Croix-Rouge; Euloma filacovi Zone, late Tremadocian (Early Ordovician); 1953, Thoral leg.; UCBL-FSL 168692 a. 2 (part) and UCBL-FSL 168693 c (counterpart). REFERRED SPECIMENS. — Six specimens (UCBL-FSL 168693, UCBL-FSL 168698, UCBL-FSL 424948, UCBL-FSL 711092 [FSL 1879 561 of Dean Shackleton 2005], MNHN. F. A 47188, MNHN. F. A 97740).	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33A3A68FC5680BB6295FBC5.taxon	diagnosis	DIAGNOSIS. — Abactinal arrangement open reticular (Figs 10 B; 11 A; 12 F). Ambital framework ossicles equidimensional to somewhat rodlike and elongate, abutted to weakly overlapping (Figs 9 A; 10 A; 11 A, D; 12 E, F). Axials in aboral view only exposing square surface over water-vascular channel, the transverse ridge obscured; series grooved longitudinally (Figs 10 B; 11 A; 12 F). In oral view, compound axials not recognized; radial-water vascular channel cylindrical, transverse ridge narrow, podial basin proximal (Figs 9; 10 A, C; 12 B, D). Adaxials moderately large, thin, broad surface longitudinally broadly grooved (Figs 9 C; 10 B, C; 11 C, D; 12 B). Adradial-most adaxial configurations not uniform but complexly varied both within and among specimens (Figs 9; 10; 11 C; 12 B, D).	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33A3A68FC5680BB6295FBC5.taxon	description	DESCRIPTION Overall form in life low-arched, outline subpentagonal; arms broad, triangular, taper gradual. Abactinals delicate, spiculate, rod-like and multiradiate; abactinal arrangement open hexagonal reticular. Madreporite, if any, unknown. Ambital framework well-defined and forming a continuous pentagonal series extending around the arm tip, the series not deflected toward the mouth frame to form a gap or cleft. Marginal ossicles granular to rod-like, abutted to overlapping. Axials in aboral aspect appearing approximately square, sequential axials abutted, longitudinal grooving weakly expressed, transverse ridge in aboral aspect generally obscured as preserved. Axials in oral aspect of an “ L ” - shape, form dominated by cylindrical water-vascular skeletal closure; transverse ridge generally appearing short, linear to recurved (Fig. 9 A, B; 10 C, D); podial basin on proximal side of transverse ridge. Mouth-angle ossicles when extended toward mouth area appearing relatively narrow, abutted, upright, bearing simple accessory spinelets (Fig. 11 B). Next ossicular pair (circumoral?) upright, abutted at arm midline, proximal margins curved (Fig. 11 A, B); possible small ossicle (Fig. 11 B) might represent circumoral. Terminal, if differentiated, obscure (Figs 11 A; 12 F). Adradial-most virgals judged variably differentiated and variably linked to axials, possibly locally with an embedded virgal equivalent between the axial and a more strongly differentiated second ossicle (Fig. 12 B). Abradial virgals elongate, grooved, sub-planar, termini expanded, rectangular in outline, edges narrow in ossicles rotated laterally; adjacent virgalia not closely spaced, perhaps not close enough to have formed a continuous platform when deflected distally. Localized alignment of granular debris suggests presence of virgal accessories. Other possible accessories not recognized.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33A3A68FC5680BB6295FBC5.taxon	discussion	REMARKS Interpretation of Villebrunaster and Ampullaster is entangled in a number of morphological complexities as well as the uncertainties of preservation. Villebrunaster is most clearly differentiated by axial shape and complexities of the immediately adjacent adaxials. The axial transverse ridge can be recurved as to partially enclose podial basins (Figs 9 A, B; 10 C, D). The apparent circumoral is enlarged, the adoral edge curved, thereby potentially reflecting presence of a podium directed toward the mouth. An apparent small ossicle is developed between the MAO and the “ circumoral ” (Fig. 11 B), it potentially the homologue of the enlarged flange or circumoral of Thoralaster (Fig. 7 A, C). Madreporite presence in Villebrunaster was noted but not illustrated (Dean Shackleton 2005, char. 77), and no example was recognized here. The ambital framework of Villebrunaster is well-defined but somewhat irregular, locally appearing to form a linear series, locally appearing slightly overlapping. Small virgal accessories occur (Fig. 10 C, D). Marginal and abactinal accessories are not recognized although widely occurrent fine debris might indicate presence.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33E3A68FED186996135FAD5.taxon	type_taxon	TYPE SPECIES. — Ampullaster ubaghsi Fell, 1963 b.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33E3A68FED186996135FAD5.taxon	diagnosis	DIAGNOSIS. — As for Ampullaster ubaghsi, the type and only recognized species.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33E3A57FEE7879E61DFFE5B.taxon	description	(Fig. 13)	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33E3A57FEE7879E61DFFE5B.taxon	materials_examined	TYPE MATERIAL. — Holotype. France • 1 specimen (oral surface exposed; much ossicular surface detail lost); Hérault, Saint-Chinian; Euloma filacovi Zone, late Tremadocian (Early Ordovician); Villebrun leg.; UCBL-FSL 168673 (Fig. 13 A-D).	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33E3A57FEE7879E61DFFE5B.taxon	diagnosis	DIAGNOSIS. — First virgals aligned in well-defined series between successive virgalia; first virgals uniform, longitudinally elongate and shelf-like, possibly exhibiting an outer rim edging an inner, inclined surface. Marginals appearing small, irregular, perhaps weakly elongate; overall, marginal series uniform. Abradial virgals possibly relatively slender, otherwise similar to Villebrunaster.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33E3A57FEE7879E61DFFE5B.taxon	description	DESCRIPTION Overall form in life low-arched, outline subpentagonal; arms broad, triangular, taper gradual. Abactinals spiculate, rod-like, arrangement reticulate. Ambital framework of relatively small, irregular, granular to rod-like ossicles forming a well-defined marginal series continuous across the interbrachia, not deflected toward mouth frame to form a gap or cleft. In oral aspect, axials “ L ” - shaped, form dominated by enlarged, skeletally closed, cylindrical water-vascular channel. Transverse ridge narrow, linear. Lateral edges of first virgals narrow, bar-like. Abradial virgals potentially extremely slender, elongate, rod-like. Accessories not clearly recognized, some debris suggests possible presence.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC33E3A57FEE7879E61DFFE5B.taxon	discussion	REMARKS Ampullaster is known only from the holotype, it nearly complete and exposed in oral aspect. At the time of recognition, both Ampullaster and Villebrunaster were assigned to a new Villebrunasteridae (Fell, 1963 b). Dean Shackleton (2005: 68), however, synonymized Ampullaster with Villebrunaster based primarily on equating differentiated adradial ossicles found in both as so-called “ intervirgal struts ”. The interpretation of Dean Shackleton earlier was accepted (Blake & Guensburg 2015) but it is rejected here, the intervirgal struts reinterpreted as adradial adaxials rather than calling for a new ossicular category. The adradial adaxials of the two generic designates are argued as differing enough in morphology and positioning as to be treated as independently derived from a more stemward state (e. g. such as that of Chinianaster), thereby justifying retention of the generic status of Ampullaster. The so-called “ intervirgal struts ” of Villebrunaster are much varied in shape and orientation both among and within individuals (Figs 9 A; 10; 11 C; 12 B), whereas corresponding ossicles of Ampullaster (Fig. 13) are regular in form and arrangement, each forming a shelf that partially confines the podial basin in a manner suggestive of expressions found in stenuroids (Spencer 1940: fig. 331; Blake 2024). No direct linkage between somasteroids and stenuroids is suggested. Other apparent adaxial variants are found in Chinianaster (Fig. 2 A), in a Chinianaster - like unassigned specimen (Fig. 14 G), and different adaxial specializations have been recognized in a number of problematic early asterozoans (e. g. Blake et al. 2020; Blake 2024). Adaxial differentiation thus was widespread not only within the Somasteroidea but also among early asterozoans in general, the varied specializations affording apomorphies serving to differentiate among both class-level asterozoan entities as well as a few genera not assigned at the class level (Blake 2013, 2018, 2024). Further potentially contributing to generic separation, marginals of Ampullaster appear smaller and more irregular than those of Villebrunaster. Abradial virgals of the Ampullaster appear slender and rod-like; if, however, these are similar to virgals of Villebrunaster and Chinianaster and were rotated into plan view, they might prove comparable, as is suggested by a small area of the holotype (Fig. 13 B, lower right). Added comments are included above under “ Adaxial skeleton. ” In the original diagnosis of Fell (1963 b), marginal series were interpreted as edging deep interradial “ V ” - shaped “ clefts ” that produced petaloid arm outlines. It is argued here that the ambital framework was continuous across the interbrachium, as in all somasteroids. Fell (1963 b) envisioned presence of gradational changes of axial expression along the length of the arm of Ampullaster, the most important the presence of skeletal discontinuities interpreted as podial pores. The interpretation is not accepted here.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3013A57FC8F80DB63CAFB44.taxon	type_taxon	TYPE GENUS. — Archegonaster Jaekel, 1923.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3013A57FC8F80DB63CAFB44.taxon	diagnosis	DIAGNOSIS. — Abactinal skeleton limited to tiny granules. Ambital framework ossicles proportionately large, angular, forming a linear sequence. Axials “ T ” - shaped, gaps between successive axials suggesting podial pores. Water-vascular channel not skeletally closed orally. Virgalia not known to reach mouth frame. First virgal strongly differentiated.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3013A57FC8F80DB63CAFB44.taxon	discussion	REMARKS For purposes of comparison, the diagnosis is written in parallel with that for the Chinianasteridae. The Archegonasteridae is known only from A. pentagonus; the diagnosis applies at the species level.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3013A57FF5286F963D4FD1B.taxon	materials_examined	TYPE MATERIAL. — Holotype. United States • 1 specimen; south-central Nevada, Ely Springs Mountain Range; Lower Pogonip Group, late early to middle Floian (Early Ordovician); PRIP UI X- 4751.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3013A57FF5286F963D4FD1B.taxon	distribution	TYPE LOCALITY AND HORIZON. — Lower Pogonip Group, Early Ordovician (late early to middle Floian); Ely Springs Mountain Range, south-central Nevada, United States.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3013A57FF5286F963D4FD1B.taxon	description	DESCRIPTION Overall form in life low-arched, outline substellate; arm outline in life triangular, quite abruptly tapering. Abactinals irregular, abutted, small, granular to plate-like. Madreporite unknown. Ambital framework well-defined, series forming a continuous outline extending around the arm tip, not deflected toward the mouth frame; marginals rod-like, robust, overlapping, alignment irregular to regular; accessory faceting not recognized. Axials approximately equidimensional, aboral appearance unknown; in oral aspect, radial water-vascular channel enclosed, small, tubular. Axials approximately bilateral both along and perpendicular to transverse ridge; podial basin shared by sequential axials; compound axials not recognized. Mouth frame ossicles small, appearing little differentiated from more distal ossicles; mouth-angle ossicles rectangular. First virgal short, otherwise similar to more lateral virgals. Abradial virgals somewhat enlarged irregular to cylindrical, rod shaped. Any accessories unknown.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3013A57FF5286F963D4FD1B.taxon	discussion	REMARKS The differing preservational styles of Ophioxenikos and the French-Moroccan genera render comparisons difficult. Floian Ophioxenikos is younger than Tremadocian Cantabrigiaster and the Saint Chinian genera but older than Middle Ordovician Archegonaster.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3013A57FF12801B62F6FBE5.taxon	description	urn: lsid: zoobank. org: act: FDF 53 B 0 D- 66 B 0 - 46 B 5 - A 22 A-B 60 C 7 C 4 BB 7 CD	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3013A57FF12801B62F6FBE5.taxon	type_taxon	TYPE GENUS. — Ophioxenikos Blake & Guensburg, 1993.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3013A57FF12801B62F6FBE5.taxon	diagnosis	DIAGNOSIS. — Substellate Chinianasteridae. Abactinals granular to plate-like, closely appressed. Ambital framework ossicles moderately elongate, aligned, weakly overlapping. Radial water-vascular channel small; skeletally closed. Podial basin boundary approximately medial, basin shared equally by successive axials. Adradial adaxials weakly differentiated, virgalia relatively short.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3013A57FF12801B62F6FBE5.taxon	discussion	REMARKS For purposes of comparison, the diagnosis is written in parallel with those for the Chinianasterinae and Villebrunasterinae. The Ophioxenikosinae n. subfam. is known only from O. langenheimi; the diagnosis applies at the species level.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3013A54FC63875E65BEF846.taxon	materials_examined	TYPE MATERIAL. — Holotype. Czech Republic • 1 specimen; Prague Basin, Osek; Šárka Formation, Darriwilian (Middle Ordovician); NMP L 10143 (part) and NMP L 10144 (counterpart). REFERRED SPECIMENS. — Reviewed from the literature (see Smith & Jell 1990; Dean Shackleton 2005).	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3013A54FC63875E65BEF846.taxon	distribution	TYPE LOCALITY AND HORIZON. — Šarká Formation (Llanvirn), close to Ošek, Prague Basin, Czech Republic.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3013A54FC63875E65BEF846.taxon	description	DESCRIPTION Somasteroid in life low-arched, outline pentagonal. Aboral skeleton limited to granules. Madreporite aboral, surface of radiating ridges and grooves. Ambital framework well-defined, marginals robust. Axials “ T ” - shaped, overlapping, with a large opening, an apparent podial pore. First adaxials strongly differentiated, more lateral adaxials proportionately small, rod-like. Proximal virgalia not recognized.	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
467887FDC3013A54FC63875E65BEF846.taxon	discussion	REMARKS The Jaekel (1923) treatment of Archegonaster was cursory, the specific name later designated from a Jaekel manuscript (Spencer 1951: 101). Morphology was reviewed in detail by Spencer (1951), Smith & Jell (1990), and Dean Shackleton (2005).	en	Blake, Daniel B., Lefebvre, Bertrand (2025): The class Somasteroidea and its significance among early Asterozoa (Echinodermata). Comptes Rendus Palevol 24 (23): 449-487, DOI: 10.5852/cr-palevol2025v24a23, URL: https://doi.org/10.5852/cr-palevol2025v24a23
