Glyptocidaridae
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| Glyptocidaridae | |
|---|---|
 | |
| Glyptocidaris crenularis | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Echinoidea |
| Order: | Stomopneustoida |
| Family: | Glyptocidaridae Jensen, 1982 |
| Genera | |
Glyptocidaridae is a family of sea urchins in the order Stomopneustoida. It contains a single genus, Glyptocidaris, described by Alexander Agassiz in 1864, with one extant species, Glyptocidaris crenularis.[1] M. Jensen erected the family in 1982 on the basis of a cladistic analysis of Euechinoidea.[2] The species is found in the northwest Pacific Ocean, from Japan to Korea and northern China.[3][4]
Synonyms
Alexander Agassiz described the genus Glyptocidaris and its type species G. crenularis in 1864, based on specimens collected by Dr. W. Stimpson during the North Pacific Exploring and Surveying Expedition.[5] Its syntype (MCZ 1105) was collected from Hakodate, Japan.[3]
Glyptocidaris was long classified as the sole living representative of the order Phymosomatoida, because its tubercles are imperforate and crenulate, features shared with phymosomatoid sea urchins.[6] However, its ambulacral plate compounding resembles that of stomopneustid sea urchins rather than phymosomatoids, and it has a small hemicyclic apical disc attached to the corona, unlike the large monocyclic disc typical of Phymosomatoida.[6] Jensen erected the family Glyptocidaridae in 1982, and Kroh and Smith confirmed its placement in Stomopneustoida in 2010 following a phylogenetic analysis of 169 taxa and 306 skeletal characters.[2][6]
Stomopneustoida contains only two extant families: Glyptocidaridae and Stomopneustidae, each with a single living species.[6]
Several names have been placed in synonymy with Glyptocidaris:[1]
- Heteractis Lambert, 1897
- Heteractechinus Lambert & Thiéry, 1914
- Eoglyptocidaris Nisiyama, 1966 †
G. crenularis has also been placed in two other genera:[3]
- Coptosoma crenulare (A. Agassiz, 1864)
- Phymosoma crenulare (A. Agassiz, 1864)
A fossil subspecies, Glyptocidaris crenularis stenozona Nisiyama, 1966, has been described.[3]
Description
Glyptocidaris crenularis has a moderately sized, low hemispherical test with a roughly pentagonal outline.[7] Adults reach a test diameter of about 60–67 mm and a body weight of roughly 70–96 g under laboratory conditions.[8] Each ambulacral plate consists of three primary plates and two demi-plates, a structure that distinguishes the genus from both phymosomatoids and other stomopneustids.[4] Ambulacra are almost half as broad as the interambulacra, and narrow bare lines run along the midlines of both ambulacral and interambulacral zones from the apical system nearly to the ambitus.[4]
The tubercles are imperforate and crenulate.[6] Globiferous pedicellariae have long terminal hooks, and the stalks bear one to six lateral processes covered by membranes, giving them a fin-like appearance.[4]
Distribution and habitat
Glyptocidaris crenularis occurs in the northwest Pacific Ocean. In Japan it has been recorded along the coasts of Hokkaido and northern Honshu, including the Tsugaru Strait.[9][5] On the Korean coast of the Yellow Sea, it has been collected at Daludo Island and Mohang harbour.[4] In China it occurs in the Yellow Sea and Bohai Sea, particularly around Dalian.[8]
Occurrence records span depths of approximately 20–150 m on rocky substrates.[9] It inhabits crevices, cracks, burrows, and spaces beneath rocks and boulders in benthic environments.[8]