Cheirocystis fultonensis

Classification
Phylum: Echinodermata
Class: Rhombifera
Order: Glyptocystitida
Family: Cheirocrinidae
Genus: Cheirocystis
Species: Cheirocystis fultonensis (Sumrall & Schumacher, 2002)

Taxonomic Details

Formerly: Glyptocystites fultonensis

Stratigraphic Occurrences

C.fultonensis_strat

Geographic Occurrences

		
Map point data provided by iDigBio.

Stratigraphic Description

Sequences (Formations)

  • C1 Sequence (Clays Ferry/Kope: Economy/Fulton; Lexington Limestone/Point Pleasant)

Identification in Hand Sample

  • Small number of pectinirhombs
  • Long, tapering attached stalk
  • High, sharp, hexagonal ridges
  • Medium-sized, elongate theca
  • Very faint growth lines

Cheirocystis fultonensis from the Kope Formation of Brooksville, Kentucky (OUIP 160)

Published Description

Meyer & Davis (2009):

  • Two species of rhombiferans are found in the Cincinnatian. Cheirocystis fultonensis is restricted to the lowermost Kope Formation (Fulton Shale) (Sumrall and Schumacher 2002). This species has an elongate theca and a long, tapering attached stalk (Fig. 12.11C).

Broadhead & Sumrall (2003):

  • In cheirocrinids both the number of pectinirhombs and the number of dichopores increased during ontongeny. Cheirocystis has a relatively small number of pectinirhombs for a cheirocrinid (eight as opposed to a maximum of 19, Table 1), and the juvenile specimen of Cheirocystis fultonensis shows a reduced number of pectinirhombs relative to more mature specimens. Interestingly , three of the four pectinirhombs present in the juvenile Cheirocystis specimen correspond exactly with the positions in three of the four pectinirhombs that are consistently present in Sprinkleocystis (Fig. 5).

Sumrall and Schumacher (2002):

  • Theca medium-sized, cylindrical; holotype 23 mm high, 12 mm wide; maximum width at infralateral circlet; plates in closed circlets; pectinirhombs of mature specimens extend rhomb-bearing sutures forming unusual three-plate junctions. BB four, wider than high, each with high central node near stem facet connected by high ridges forming square base without basal cavity….Thecal plates covered by network of ridges that radiate from plate centers to plate edges, many do not connect with central node on one or both sides, pattern of ridges consistent between specimens, but extremely mature specimen CMC P50605 showing a few additional ridges parallel to larger primary ridges; ridges extremely high, solid, with knife-edge, between ridges plate surfaces smooth with very faint growth lines; some plated with faint, almost imperceptible ridges that extend between plate centers and three plate junctions. OO circlet with much stronger growth lines. Periproct large, surrounded by IL4, IL5, LI, LI4, and L5; border slightly beveled on inner lip for attachment for periproctal membrane. Periproctal membrane and anal pyramid unknown.

Davis (1998):

  • Cystoid. Single plate. Note hexagonal ridges. Complete animal unknown. Common in Edenian and Maysvillian; Exact range unknown.