Salairocrinus apertus, Prokop & Slámová, 2012

Prokop, Rudolf J. & Slámová, Radana, 2012, New Species Of Crinoids Based On Their Columnals And Stem Fragments (Col.), From The Lower Devonian Zlíchov Limestone (Barrandian Area, The Czech Republic), Acta Musei Nationalis Pragae Series B 68 (3 - 4), pp. 133-138 : 134-135

Salairocrinus apertus sp. n.

Pl. 1, figs 11, 12, text-fig. 2

1987

Salairocrinus apertus sp. n. (col.): Slámová MS; p. 83-84, pl. XI, figs 12-13, text-fig. 23.

Ho l o t y p e: Isolated columnal NMP L 26667 figured by Slámová 1987, on pl. XI, fig. 13 and herein on Pl. 1, fig. 12.

T y p e h o r i z o n: “Chapel Horizon” at the base of Zlíchov Limestone, Lower Devonian, Zlíchovian (= Lower Emsian).

T y p e l o c a l i t y: Abandoned quarry “U kapličky”, Praha-Zlíchov.

M a t e r i a l: In addition to the holotype and paratypes, 52 isolated columnals and 19 pluricolumnals were obtained from washings from the type locality. The species is also recorded from Praha-Lochkov, “Hvížďalka” Quarry.

D e s c r i p t i o n: Stem homeomorphic, circular in outline, composed of thin columnals with flat articular facets and weakly convex latera. Symplexy articulation, crenularium consisting of fine, straight, dichotomic crenellae, which extend up to the latera. Areola is absent, lumen pentagonal to broadly pentastellate with rounded tops from which extend prominent grooves, up to 1/3 of the width of the facet.

C o m p a r i s o n: Salairocrinus apertus sp. n. (col.) differs from the other species of the genus Salairocrinus in the prominent grooves extending from the lumen corners. From the species Salairocrinus carinatus LE MENN, 1980 (col.) it differs in addition by the considerably shorter columnals. Pluricolumnals of Salairocrinus kerovenonsis LE MENN, 1985 are heteromorphic and their taller columnals have a coarse crenularium.

O c c u r r e n c e: Lower and Middle Devonian of Russia (North Ural Mts.), Eifelian of Kazakhstan and Turkestan (South Tian-Shan Mts), France (Siegenian, Givetian) and the Czech Republic (Pragian, Zlíchovian = Lower Emsian).

nodal nodal lumen height diameter diameter

NMP L 26667 (holotype): 1.1 9.6 0.6 NMP L 26666 : 0.9 10.2 0.5

Dimensions in mm.

Figures

Text-fig. 2. Salairocrinus apertus sp. n. (col.). A – columnal in facetal view. B – columnal in lateral view. C – cross section of columnal. Drawing by Radana Slámová.