#valvatida

[snototter]

A purple sunstar (Solaster endeca) in the White Sea

by Alexander Semenov

[uncharismatic-fauna]

Uncharismatic Fact of the Day

This star isn't far away-- it's just very, very small! Parvulastra parvivipara is the smallest known species of starfish, with adults reaching only 1 cm (0.4 in) in diameter. What's even more interesting, the Tasmanian live-beaing sea star is a self-fertilizing hermaphrodite, and juveniles hatch and develop within their parents gonads before being released, making them ovoviviparous.

(Image: A trio of Tasmanian live-bearing sea stars (Parvulastra parvivipara) by John Eichler)

[have-you-seen-this-animal]

Have you seen the chocolate chip sea star (Protoreaster nodosus)?

I have now

Yes, in photos/videos

Yes, irl

I'm not sure

Voting ended onMar 3, 2025

[every-day-creechur]

Bradley's Sea Star Mithrodia bradleyi

Bradley's sea star lives in the eastern Pacific Ocean from Mexico to Chile, including the Gulf of California. It is also found in the Galapagos Islands. It lives on rocky bottoms and coral reefs from the intertidal zone to 50 metres (160 ft) deep.

image by Billy Bensted-Smith

[rattyexplores]

The Indo-Pacific Sand Star

Not as colorful as you’d imagine a sea star to be. Yet, still lovely creatures.(These stars traverse the sands on the sea shores, watch where you step!)

There also appear to be small snails on the underside of Specimen 1.

Archaster typicus

15/06/22

[animalids]

Crown-of-thorns starfish (Acanthaster planci)

Photo by Kary Mar

[nature-and-biodiversity-blog]

Chocolate Chip Sea Star Protoreaster nodosus

[alphynix]

Almost-Living Fossils Month #03 -- The Crowned Starfish

Known mainly from around Europe -- with a few records from the Atlantic coast of North America and the Caribbean -- the stauranderasterids were a family of starfish that first appeared about 190 million years ago in the Early Jurassic.

Not much is known about their life ecology, although they seem to have inhabited shallow tropical seas and like many other starfish would probably have preyed on various slow-moving marine invertebrates. Complete specimens are very rare compared to just isolated elements, making their maximum size difficult to estimate, but they likely grew to at least 5-10cm across (2″-4″).

They had enlarged ossicles forming a bumpy “crown” over their central disc, with five arms that could be either narrow and elongated (such as in Stauranderaster coronatus here) or shorter and club-shaped (like Manfredaster bulbiferus). This gave them some visual similarities to modern starfish like Protoreaster, and since they were both part of a larger grouping of starfish called valvatids it’s unclear whether these features mean that they were very closely related to each other or if it was simply due to convergent evolution.

The stauranderasterids survived until at least the Late Paleocene/Early Eocene (~56 mya), but some possible remains from Cuba date to as recently as the Early Micoene (~23-16 mya).