Echinothuriidae

Echinothuriidae Temporal range: Middle Jurassic–Recent PreЄ Є O S D C P T J K Pg N

Fire urchin (Asthenosoma varium)
Scientific classification
Kingdom:	Animalia
Phylum:	Echinodermata
Class:	Echinoidea
Subclass:	Euechinoidea
Superorder:	Diadematacia
Order:	Echinothurioida
Genera
See text

Echinothuriidae is a family of sea urchins in the order Echinothurioida. Due to their soft skeletton most are called "leather urchins", but species in the genus Asthenosoma are also known as "fire urchins" due to their bright colors and painful venomous sting.

Description and characteristics

These sea urchins have a disc-like body, more or less bulging, structured by a flexible test, which is nearly unique among sea urchins. Most species can grow quite big and live in deep seas, though some genera contain shallow species (especially Asthenosoma).^[1]

The test is composed of thin and weakly calcified plates, not always continuous. The spines are attached to perforated and non-crenulated tubercles. Spines from the oral face are ending with a hyaline hoof, which allows walking on soft substrate. The jaw (Aristotle's lantern) has 5 aulodont teeth.^[2]

This family seems to have appeared at the end of the Cretaceous.^[2]

Taxonomy

The World Echinoidea Database recognises the following genera:^[3]

Sub-family Echinothuriinae Thomson, 1872a
- genus Araeosoma Mortensen, 1903b -- 19 current species and 2 fossiles
- genus Asthenosoma Grube, 1868 -- 6 current species and 1 fossile
- genus Calveriosoma Mortensen, 1934 -- 2 species
- genus Hapalosoma Mortensen, 1903b -- 4 species
Sub-family Hygrosomatinae Smith & Wright, 1990
- genus Hygrosoma Mortensen, 1903b -- 3 species
Sub-family Sperosomatinae Smith & Wright, 1990
- genus Sperosoma Koehler, 1897 -- 11 species
- genus Tromikosoma Mortensen, 1903 -- 6 species
genus Retzneiosoma Kroh, 2005 †

"†" means an extinct taxon.

Araeosoma thetidis (New Zealand, 188m depth).
Asthenosoma marisrubri
Hygrosoma sp. (abyssal species from north Atlantic)
Sperosoma sp. (abyssal species taken in Hawaii)
Tromikosoma sp. (3000m deep, California).

References

↑ Mah, Christopher L. "What are the Deepest known echinoderms ?". The Echinoblog.
1 2 "Echinothuriidae". Echinoid Directory.
↑ Kroh, A. (2015), Echinothuriidae Thomson, 1872, In: Kroh, A. & Mooi, R. (2015) World Echinoidea Database.

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