Heterochrony and paedomorphic morphology of Sprinkleocystis ektopios, new genus and species, (Rhombifera, Glyptocystida) from the Middle Ordovician (Caradoc) of Tennessee
2003 ◽
Vol 77
(1)
◽
pp. 113-120
◽
Keyword(s):
The glyptocystitoid rhombiferan Sprinkleocystis ektopios new genus and species is described from the Middle Ordovician (Caradoc) Benbolt Formation of Tennessee. This species is characterized by having four ambulacra bearing only terminal brachioles, the absence of lateral 5, and protuberant pectinirhombs and periproct. Many of its features are considered typical of the family Cheirocrinidae whereas others are more characteristic of the Glyptocystitidae. Its small size and simple ambulacral and pectinirhomb structures suggest a paedomorphic evolutionary origin, and its thecal morphology further suggests that the validity of a separate Cheirocrinidae and Glyptocystitidae may need reevaluation.
1996 ◽
Vol 70
(4)
◽
pp. 602-609
◽
Keyword(s):
2002 ◽
Vol 33
(1)
◽
pp. 23-34
◽
Keyword(s):
Keyword(s):
1999 ◽
Vol 65
(2)
◽
pp. 151-161
◽
Keyword(s):
Keyword(s):
2008 ◽
Vol 121
(3)
◽
pp. 365-373
◽