Welcome to the Treatise on Invertebrate Paleontology!
Please enter a genera name to retrieve more information.
Hemiaster
Classification
Phylum:
Echinodermata
Subphylum:
Echinozoa (sea urchins, holothurians, etc.)
Class:
Echinoidea
Subclass:
Euechinoidea (sand dollars) - Superorder Atelostomata
Order:
Spatangoida
Suborder:
Hemiasterina
Family:
Hemiasteridae
Formal Genus Name and Reference:
Hemiaster AGASSIZ, 1847, p. 16
Type Species:
*Spatangus bufo Brongniart, 1822, p. 84, SD SAVIN, 1903, p. 22
Images
(Click to enlarge in a new window)
Fig. 442,1. *H. bufo (Brongniart), U.Cret. (Cenoman.), Fr., 1a-d, aboral, oral, lat., post., X1.5 (142)
Synonyms
Leucaster, Peroniaster, Perionaster
Geographic Distribution
cosmop.
Age Range
Beginning Stage in Treatise Usage:
L.Cret.(Apt.)
Beginning International Stage:
Aptian
Fraction Up In Beginning Stage:
0
Beginning Date:
121.4
Ending Stage in Treatise Usage:
Rec.
Ending International Stage:
Meghalayan
Fraction Up In Ending Stage:
100
Ending Date:
0
Description
Test broad, high relative to length, abruptly truncated in rear, showing slight frontal sinus, apical system ethmophract, with 4 gonopores, frontal ambulacrum nonpetaloid or semipetaloid, with small round pores, paired ambulacra having relatively short petals, frontal pair longest
References
Museum or Author Information
Classification
Phylum:
Echinodermata
Subphylum:
Echinozoa (sea urchins, holothurians, etc.)
Class:
Echinoidea
Subclass:
Euechinoidea (sand dollars) - Superorder Atelostomata
Order:
Spatangoida
Suborder:
Hemiasterina
Family:
Hemiasteridae
Formal Genus Name and Reference:
Hemiaster AGASSIZ, 1847, p. 16
Type Species:
*Spatangus bufo Brongniart, 1822, p. 84, SD SAVIN, 1903, p. 22
Images
(Click to enlarge in a new window)
Fig. 442,1. *H. bufo (Brongniart), U.Cret. (Cenoman.), Fr., 1a-d, aboral, oral, lat., post., X1.5 (142)
Synonyms
Leucaster, Peroniaster, Perionaster
Geographic Distribution
cosmop.
Age Range
Beginning Stage in Treatise Usage:
L.Cret.(Apt.)
Beginning International Stage:
Aptian
Fraction Up In Beginning Stage:
0
Beginning Date:
121.4
Ending Stage in Treatise Usage:
Rec.
Ending International Stage:
Meghalayan
Fraction Up In Ending Stage:
100
Ending Date:
0
Description
Test broad, high relative to length, abruptly truncated in rear, showing slight frontal sinus, apical system ethmophract, with 4 gonopores, frontal ambulacrum nonpetaloid or semipetaloid, with small round pores, paired ambulacra having relatively short petals, frontal pair longest