A very common chalk starfish, ranging throughout the chalk.  The marginal ossicles are slightly cubic, with a gently pitted outer surface.  Individuals are typically small, with a robust marginal frame and weakly developed arms.  Metopaster is superficially quite similar, but has a bordered ossicle-ornamentation and  an expanded ultimate superomarginal (distinguish Metopaster and Crateraster).

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1).  (A) Oral surface of a very well preserved individual (x1.5, White Chalk, SE England, BMNH (British Museum (Natural History) London) E2582; (B) Typical marginal ossicle, with a gently ornamented surface of weakly-rimmed pits (x8, Peacehaven, Newhaven Chalk Formation, Randell Collection, RR1703.  Image (A)  © 2005 The Natural History Museum, by kind permission.

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2).  Oral views of two beautifully preserved individuals; (A) x1.7, White Chalk, Charlton, Kent, BMNH (British Museum (Natural History) London) E2023; (B) x3, White Chalk, 'Brighton', Willett collection, Booth Museum, BMB 007829, by kind permission of John Cooper.  Image (A)  © 2005 The Natural History Museum, by kind permission.

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3).  (A, B) Aboral views of two well articulated and near complete specimens retaining many of the ossicles of the central disc (A x2.8, B x2.5, Seaford Chalk, Thanet Coast, Kent, in the collection of Keith Little).  Images © 2012 Keith Little, by kind permission.

4).  Oral view of a relatively small individual with a near complete marginal frame (x3.3, Seaford Chalk, Thanet Coast, Kent, in the collection of Keith Little).  Images © 2011 Keith Little, by kind permission.

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5).  Near complete individuals; (A) Aboral view of a  mature, relatively large individual, with numerous marginals and modest arms (x2, Birling Gap, Seaford Chalk Formation, R. Strevens Collection); (B) Oral view of a typical specimen with a robust frame and few marginals (x3, Alton area (Hampshire)?, White Chalk, (HCCMS (Hampshire County Council Museum's Service) collection, stored at Gosport Museum, GOS1983.427, by kind permission of Dave Kemp, HCCMS).

6).  Lateral (side) profile of a typical small individual, with blocky marginals and slightly swollen arms (x4, Alton area (Hampshire)?, White Chalk, (HCCMS (Hampshire County Council Museum's Service) collection, stored at Gosport Museum, GOS1983.427, by kind permission of Dave Kemp, HCCMS).

7).  Lateral profiles of (A) juvenile and (B) adult arm tips; (A) A small (juvenile?) individual, with a relatively slender, upturned arm-tip (x7, Culver Chalk, Gaster's Pit 10, Worthing, West Sussex, Randell Collection, RR0113); (B) Sharply upturned arm-tip from a large individual (x4, White Chalk, Worthing area?, Randell Collection, RR1535).

8).  Detail of the oral surface of a very well preserved individual whose mouth angle plates are still articulated (x5.0, White Chalk, SE England, BMNH (British Museum (Natural History) London) E2582.  Image © 2005 The Natural History Museum, by kind permission.

9).  Aboral view of a new semi-complete specimen from the Seaford Chalk of Beachy Head, East Sussex (x2, Randell Collection).  See details of the collection and preparation here.

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10).  Semi-complete specimen from the Seaford Chalk of Beachy Head, East Sussex, (András Zboray Collection): (A) Oral view of the specimen, x2.0; (B) Lateral view showing excellent articulation of arm-tips, oral surface down, x2.0.  Images © 2010 András Zboray of www.fjexpeditions.com, by kind permission.

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11).  (A, B) Oral views of two semi-complete specimens (x2, Seaford Chalk, Thanet Coast, Kent, in the collection of Keith Little).  Images © 2011 Keith Little, by kind permission.

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12).  (A) Part of a well preserved individual (x2.5).  (B) Inferomarginals under low-angle lighting, revealing the subtle surface ornament (x7) (Both White Chalk, Worthing area?, Randell Collection, (A) RR1534 (B) RR1535).

13).  Aboral view of a partial specimen from the Newhaven Chalk of Palm Bay, Thanet Coast, Kent (x3.5, in the collection of Keith Little).  Image © 2010 Keith Little, by kind permission.

14).  Aboral view of a part of a well preserved juvenile (Newhaven Chalk, Palm Bay, Thanet Coast, Kent, x10.0, in the collection of Keith Little).  Image © 2010 Keith Little, by kind permission.

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15).  Oral views of reconstructed arm tips from (A) a small (juvenile?) individual (x4, Culver Chalk, Gaster's Pit 10, Worthing, West Sussex Randell Collection, RR0113); (B) Larger individual with a ore compressed marginal frame (x4, Old Nore Point, near Peacehaven, Newhaven Chalk Formation, Randell Collection, RR1196).