Marine Invertebrates Codexery

Sand dollar

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Sand dollar

Frédéric Ducarme · via Wikipedia: Sand dollar · CC BY-SA 4.0

Sand dollars are flat, burrowing sea urchins of the order Clypeasteroida, also called sea cookies or cake urchins.[1] Living sand dollars are covered by velvet-textured spines with tiny cilia.[2]

Scientific classification

  1. KingdomAnimalia
  2. PhylumEchinodermata
  3. ClassEchinoidea
  4. OrderClypeasteroida

Sources: Wikipedia taxobox: Sand dollar (CC BY-SA 4.0)

Quick Facts

Order
Clypeasteroida

Facts from the source article.

Key facts and history

Sand dollars diverged from other irregular echinoids during the early Jurassic, with the first true genus, Togocyamus, appearing in the Paleocene.[3] By the middle Eocene, sand dollars had a worldwide distribution.[4] They inhabit temperate and tropical zones along all continents, living on or just beneath sandy and muddy areas below the mean low tide line.[5] Groups that appear more modern first showed up in the Eocene, shortly after the appearance of Togocyamus.[6]

Burrowing and creeping through sediment is made possible by the spines located on both the upper and lower surfaces of the animal.[7] Algae and organic material from the ocean floor make up the usual diet of sand dollars.[7] The cloning process, which can last up to 24 hours, produces larvae that are two-thirds the length of the original.[8]

What the cited sources add

The Embryo Project Encyclopedia notes that sand dollars are common marine invertebrates in the phylum Echinodermata, sharing the class Echinoidea with sea urchins.[9] William Eugene Berg used the sand dollar Dendraster excentricus to pioneer mid-twentieth-century studies of protein synthesis in embryos.[9] The same source states that sand dollars are easy to work with in the classroom as model organisms for fertilization and development studies.[9] Louise Palmer discovered during the 1930s that various salts could induce sand dollars to shed mature gametes without killing them.[9]

A 1949 method by Tyler, still widely followed, involves injecting 0.5 cc of 0.5 M KCl into the sand dollar's mouth.[9] The Enchanted Learning printout notes that sand dollar larvae travel many miles swept along by ocean currents.[10] It also states that sand dollars are eaten by sea stars, snails, and skates.[10]

References

  1. Wikipedia, "Sand dollar" (CC BY-SA 4.0), which cites: Kennedy, "Sand Dollar Facts", ThoughtCo, 9 October 2019 (original not read by us) en.wikipedia.org
  2. Wikipedia, "Sand dollar" (CC BY-SA 4.0), which cites: "Sand Dollar Printout - Enchanted Learning Software", Enchanted Learning, 2000; Grzimek, "Grzimek's animal life encyclopedia", Gale, April 2024 (we also read that source) en.wikipedia.org
  3. Wikipedia, "Sand dollar" (CC BY-SA 4.0), which cites: Kier, "Rapid evolution in echinoids", Palaeontology, January 1982, p. 1–9 (we also read that source) en.wikipedia.org
  4. Kier, "Rapid evolution in echinoids", Palaeontology, January 1982, p. 1–9. facts only, no text reused. palass.org
  5. Wikipedia, "Sand dollar" (CC BY-SA 4.0), which cites: "Encyclopedia of Animals", Great Neck Publishing, 2017 (original not read by us) en.wikipedia.org
  6. Wikipedia, "Sand dollar" (CC BY-SA 4.0), which cites: The Paleobiology Database (original not read by us) en.wikipedia.org
  7. Wikipedia, "Sand dollar" (CC BY-SA 4.0), which cites: Sayre, "Seashore", Twenty-First Century Books, April 2024; Grzimek, "Grzimek's animal life encyclopedia", Gale, April 2024 (we also read that source) en.wikipedia.org
  8. Wikipedia, "Sand dollar" (CC BY-SA 4.0), which cites: Choi, "Split Defense", Scientific American, May 2008, p. 38 (we also read that source) en.wikipedia.org
  9. "Inducing Fertilization and Development in Sand Dollars Embryo Project Encyclopedia", embryo.asu.edu. facts only, no text reused. embryo.asu.edu
  10. "Sand Dollar Printout - Enchanted Learning Software", Enchanted Learning, 2000. facts only, no text reused. enchantedlearning.com

Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Sand dollar (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.

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Sand dollar · Aquatic Invertebrates

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Sources

Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.

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