This week’s post is from Liz Clark, PhD, a biologist/paleontologist at Yale University (New Haven, USA). If you would like to write for Anatomy to You, get in touch via Facebook or Twitter. Echinoderms are a group of invertebrates that include sea stars, sea urchins, sand dollars, sea cucumbers, crinoids and brittle stars, and they’re about…
Tag: echinoderm
#TomographyTuesday: Watch incredible CT scan reveal young brittle stars developing inside their parent!
Most marine invertebrates, and certainly most brittle stars, spawning gametes (eggs and sperm cells) into the oceans and the embryos are formed and grow externally. But a few species carry live young, with their offspring developing within the parent’s body. How exactly these creatures – which have pretty small central bodies to begin with – accommodate…
Young sea star
Close-up view of a young sea star or starfish, demonstrating two of the key anatomical features of echinoderms, the phylum to which they belong. The first is the pentaradial (five-way radial) symmetry that gives it its characteristic star shape, which is highly unusual. This symmetry means that, unlike most ‘higher’ animals, the sea star has no head or…
Mouth of a brittle star, Ophiocoma echinata
Five mouth parts of a brittle star, with teeth. Brittle stars often eat detritus and sometimes filter organic particles in the water column. This specimen was collected in Bocas del Toro, Panama. Image: LSR
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