Lepadocystis

Classification
Phylum: Echinodermata
Class: Rhombifera
Order: Dichoporita
Family: Callocystitidae
Genus: Lepadocystis Carpenter, 1891
Cincinnatian Species: Lepadocystis moorei

 

Taxonomic Details

  • 1879 Lepadocrinus Zittel (part), Handb. Pal, 1, p. 421
  • 1889 Lepadocrinus Miller (part), N. A. Geol. Pal., p. 257.
  • 1891 Lepadocystis Carpenter, Linn. Soc. Jour. Zool., 24, p. 10.
  • 1899 Meekocystis Jaekel, Stammeages. Pelmat., 1, Thecoidea u. Cystoidea, Berlin, p. 277.
  • 1900 Lepadocystis Bather, Treatise on Zoology, pt. 3, Echinodermata, p. 61.
  • 1908 Lepadocrinus Cumings, 32d Ann. Rep. Dep. Geol. Nat. Res. Indiana, p. 714.
  • 1914 Lepadocystis Foerste, Bull. Sci. Lab. Denison Univ., 17, p. 458.

Geologic Range
Late Ordovician

Common Paleoecology
Lepadocystis is an extinct genus of stationary intermediate-level epifaunal suspension feeders

Identification in Hand Sample:

  • Characterized by subovate theca
  • Open radial circlet
  • Five short ambulacra
  • Theca subovate to ellipsoidal

Geographic Occurrences

Published Description

Sumrall and Carlson (2000):

  • The interruption of the lateral circlet by IL3/R3 in the larger specimens of Lepadocystis is interpreted as a genus level characteristic. Among glypotocystitids, open vs. closed thecal plate circlets have been widely used to separate many taxa, especially in the genera. Unfortunately, open vs. closed plate circlets is not strictly a phylogenetic character, rather, there is an appreciable ontogenetic expression with juvenile specimens having closed plate circlets that become open with maturity (Sumrall and Sprinkle, 1999). Consequently, caution is suggested when using this feature as a taxobasis and it should only be used on mature specimens with large rhombs and somewhat curved sutures.

Ausich and Schumacher (1984):

  • Lepadocystis is characterized by a subovate theca; either a closed or open lateral circlet; an open radial circlet; five short ambulacra; five pectinirhombs situated at B2/IL2, L1/R5, L2/R 1, L3/R3, L4/R3; and elongate IL4 and IL5.

Treatise on Invertebrate Paleontology, Part S, Vol. 1(2) (1978):

  • Theca subovate to ellipsoidal, gerontic forms becoming pyriform and tapering to column. R circlet interrupted by L5; periproct bordered by IL4, IL5, L4 and L5; IL4 and IL5 vertically elongate; R3 very distinctive, nearly square, with 2 half-rhombs on aboral sides of plate separated only by narrow ridges; OO rather large, O1 triparthite. Ambulacra 5, relatively short, few extending below RR ambulacrum III (A) short and obstructed by 2 half-rhombs on R3. Pectinirhombs 5, B2/IL2, L1/R5, L2/R1, L3/R3, and L4/R3. Gonopore and hydropore bisected by suture through O1; hydropore shaped like broad U, slot provided with grating or crossbars. Column with large narrow rings near theca, distally decreasing in diameter, its end variously modified for attachment to objects. Ornamentation increasing in complexity to adult stage, but gerontic specimens with effaced ridges.

Foerste (1914):

  • Lepadocystinae, with oval theca composed of plates arranged as follows:
    – Basal row, with plates 4, 1, 2, 3.
    – Second row, with plates 5, 6, 7, 8, 9.
    – Third row, with plates 10, 11, 12, and 14. Plate 13 has been elevated sufficiently to be chiefly in the fourth row.
    – Fourth row, with plates 16, 17, 18, 19, and 15. Also most of plate 13.
    – Fifth row, with plates 22, 23, 24, 20 and 21.
    – Column obliquely attached at the base, with anal area on that side of the theca which has the longest curvature.
    – Anal area prominent, between plates 7, 8, 13 and 14.
    – Pectinirhombs on plates 1-5, 10-15, 11-17, 12-18, and 14-15, with more or less discrete areas of a lunate form, usually deeply impressed on the convex margin, and crossed by rather numerous dichopores.
    – Ambulacra five, reclining upon the surface of the theca and terminating usually at, or slightly beyond, the middle of plates 15, 16, 17, 18, and 19.

L. moorei