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to basin. The food gathering system of blastoids consisted of several types of ambulacra. Food entered the brachiolar ambulacra, was transferred to the side ambulacra through the brachiolar pit, then transferred to the main (median) ambulacra, and finally entered the mouth. Each of these ambulacra
336:, which were used to trap food particles and bring them to the mouth. Brachioles were delicate structures, and in fossils are not usually preserved in place. A series of five spiracle plates surrounded the star-shaped mouth, which included the
319:. In life, the theca of a typical blastoid was attached to a stalk or column made up of stacked disc-shaped plates. The other end of the column was attached to the ocean floor by a holdfast, very much like stalked
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was roofed by cover plates. The cover plates of the brachiolar groove were movable and could open, allowing food to enter, or close as needed. Other cover plates may also have been movable.
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The mouth was at the summit of the theca. Radiating like flower petals from the center were five food grooves, or
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Three
Dimensional Structure and Fluid Flow though the Hydrospires of the Blastoid Pentremites rusticus
269:, often referred to as sea buds. They first appear, along with many other echinoderm classes, in the
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421:, which are characterized by direct entrance to the individual hydrospires by way of slits; and
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Like crinoids, blastoids were high-level stalked suspension feeders (feeding mainly on
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Like most echinoderms, blastoids were protected by a set of interlocking plates of
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organisms) that inhabited clear-to-silty, moderately agitated ocean waters from
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301:, blastoids are common fossils, especially in many Mississippian-age rocks.
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454:. Philadelphia, PA: Holt-Saunders International. p. 1010.
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332:. Each ambulacrum had many long thin fine structures called
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340:, mouth and entrances to a set of five complex, folded
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period. However, blastoids may have originated in the
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period, and reached their greatest diversity in the
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479:Blastoids at UC Berkeley Museum of Paleontology
413:Blastoids are assumed to have evolved from the
417:. Blastoids are subdivided into two orders:
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433:, cannot be classified as either order.
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488:Drawings and color reconstruction of
16:Extinct class of marine invertebrates
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285:. Blastoids persisted until their
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313:, which formed the main body, or
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429:from the Middle Ordovician of
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654:Ordovician first appearances
409:List of echinodermata orders
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450:Barnes, Robert D. (1982).
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261:(class Blastoidea) are an
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133:Scientific classification
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386:; lateral view of theca.
19:Not to be confused with
639:Ordovician echinoderms
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664:Lopingian extinctions
606:Paleobiology Database
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644:Devonian echinoderms
494:www.emilydamstra.com
452:Invertebrate Zoology
659:Permian extinctions
649:Permian echinoderms
484:Palaeos.com article
380:Milwaukee Formation
251:Art Forms of Nature
244:"Blastoidea", from
21:Blastoid (embryoid)
490:Pentremites godoni
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360:Pentremites godoni
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124:Pentremites godoni
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593:Open Tree of Life
510:Taxon identifiers
311:calcium carbonate
277:subperiod of the
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542:Wikispecies
423:Spiraculata
419:Fissiculata
370:The Middle
350:anispiracle
346:hydrospires
342:respiratory
305:Description
220:Spiraculata
216:Fissiculata
176:Subphylum:
628:Categories
548:Blastoidea
518:Blastoidea
437:References
407:See also:
392:planktonic
334:brachioles
287:extinction
271:Ordovician
267:echinoderm
196:Blastoidea
38:Ordovician
634:Blastozoa
431:Tennessee
384:Wisconsin
378:from the
374:blastoid
329:ambulacra
259:Blastoids
183:Blastozoa
156:Kingdom:
150:Eukaryota
31:Blastoids
556:BioLib:
533:Q1566901
527:Wikidata
415:Cystoids
403:Taxonomy
372:Devonian
321:crinoids
299:crinoids
283:Cambrian
166:Phylum:
160:Animalia
146:Domain:
598:5292657
572:4717197
295:Permian
289:at the
263:extinct
209:Orders
189:Class:
42:Permian
559:453695
458:
254:, 1904
203:, 1825
611:30820
580:IRMNG
396:shelf
316:theca
585:1366
456:ISBN
338:anus
48:Preκ
567:EoL
293:of
291:end
248:'s
201:Say
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382:;
98:Pg
40:-
464:.
228:β
226::
193:β
180:β
103:N
93:K
88:J
83:T
78:P
73:C
68:D
63:S
58:O
53:κ
23:.
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