thiolliericrinid crinoids from the lower cretaceous of crimea

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— 651 —Heberticrinus irregularis nov. sp.De r iv a t io n o m i n i s :fig. 13 A-EThe name of the species comes from « irregularis »(irregular in Latin).H o l o t y p e :CK-88-1 (fig. 13 C) ; Leningrad Mining Institute.Ty p e l o c a l it y :Kuibyshevo, Belbek Valley, Crimea.Ty pe l e v e l :Upper Berriasian.surface. The centrodorsal surface is smooth or veryfinely granulated. Some weak fossae are seen sometimeson the radial-centrodorsal suture. The centrodorsalbasis in projected as an acute ridge and completelyoccupied by an elliptical stem facet being orientatedobliquely to the calyx axis. In some cases, the basis iswide, flat and rounded.D i m e n s i o n s :H t = 5.2 - 12.0 mm ; Dt = 6.9 - 18.5 mm ; Dc =5.0 - 12.0 mm ; A f = 37 - 50° ; Hr : Ht = 0.06-0.23 ; Bf : Lf = 0.36 - 0.50.C o m p a r i s o n :H. irregularis differs from other species of thegenus having an irregular centrodorsal and obliquecentrodorsal basis.De s c r i p t i o n :The calyx is high and rounded or roundedpentangular.The radial ring is high, cylindrical ornarrowed downwards. Free radial surface is low orrelatively high. Radial facets are narrow. The basaisare visible on the external calyx surface. The centrodorsalis high and convex with uneven externalM a t e r i a l s :17 calyxes, 18 centrodorsals, 2 brachials, 28 columnals(see table 1).D i s t r i b u t i o n :Berriasian ; Crimea.ВFig. 13 — Calyxes, controdorsal and columnal of Heberticrinus irregularis (x 3).A - CK-88-3 (calyx from side and below). В - CK-88-2 (calyx from side). С - holotype CK-88-1 (calyx from side). D - CK-88-22(columnal and its articular face). E - CK-88-8 (centrodorsal from above).Coupes dorsales, centrodorsale et columnale de Heberticrinus irregularis.A - CK-88-3 (coupe dorsale vue de côté et en dessous). B - CK-88-2 (coupe dorsale vue de côté). С - holotype CK-88-1 (coupe dorsalevue de côté). D - CK-88-22 (columnale et sa facette articulaire). E - CK-88-8 (centrodorsale vue en dessus).
— 652 —5 — RECONSTRUCTION OF THE SKELETONRo o t fo r m a t io n sIn some localities (see table 1), together with calyxesand columnals, root formations of Thiolliericrinidaewere found (Ad - see fig. 2). One cannot determinethe taxonomic position of these roots. It can only beassume that they belong to Heberticrinus heberti orUmbocrinus umbonatus (the most common species).All attachment outgrowths are individual, i.e. onlyone articular facet for a stem is present on each. Theseformations are the monocrystalline calcitic crust(without root-like projections) bearing a nearly notisolated stem socket (fig. 14 A,B). Sometimes, thestem facet is raised as a distinct eminence (fig. 14C,D). Such eminences are formed, very likely, by anaccretion of the lower columnal with the attachmentdisc. It is characteristic that a rounded swelling,resembling a parasite settling, is situated near eachraised socket. Dactylate corallite served, in mostcases, a substratum for the attachment crusts.One can m ark two peculiarities of the attachmentformations. First, a small diameter of the stem facets.It is considerably smaller than the average diameter ofcolumnals found in the same localities. This fact canmean that the Thiolliericrinidae stem is narroweddownwards from the calyx. Second circumstance :almost all stem facets on attachment formations haveevident traces of the selective dissolution. The ligamentfossae on both sides of the fulcral ridge are considerablydeepened. This dissolution is explained bythe fact that the root was left on its place long afterthe death of the animal, being exposed to the corrosionby sea water.Described root formations are analogous to thosenoted for other Thiolliericrinidae species (Étallon1859, p. 445, 447 ; Patrulius 1956a, p. 193 ; Hess1975, p. 69, pi. 25, fig. 1 ; Rasmussen 1978c, p. 879).ВFig. 14 — Root formations of Thiolliericrinidae indet. (x 2).A - CK-100-3 : attachment to a coral limestone ; stem sockets is low.В - CK-100-4 : attachment to a coral ; stem socket is low.С - CK-100-2 : attachment to a shell fragment ; stem socket is high.D - CK-100-1 : attachment to a coral limestone ; stem socket is high.Mode de fixation de quelques Thiolliericrinidae indét.A - CK-100-3 : fixation sur un calcaire corallien.В - CK-100-4 : fixation sur un polypier.С - CK-100-2 : fixation sur un fragment de coquille.D - CK-100-1 : fixation sur un calcaire corallien.
Page 1 and 2: THIOLLIERICRINID CRINOIDS FROM THE
Page 3 and 4: TABLE OF CONTENTS1 - Introduction..
Page 5 and 6: — 628 —Name of s p ecies L o ca
Page 7 and 8: 630 —
Page 9 and 10: — 632 —not only specific but al
Page 11 and 12: — 634 —Fig. 3 — Calyxes and c
Page 13 and 14: — 636 —Fig. 4A scheme of the di
Page 15 and 16: — 638 —Thiolliericrinus elongat
Page 17 and 18: — 640 —Fig. 7 — Calyxes and c
Page 19 and 20: — 642 —cavity. The primaxillary
Page 21 and 22: — 644 —D e s c r i p t i o n :T
Page 23 and 24: — 646 —T y p e s p e c ie s :Ge
Page 25 and 26: — 648 —Fig. 12 — Calyxes and
Page 27: — 650 —T y p e l e v e l :Upper
Page 31 and 32: — 654 —SIS rllAxsurface (Loriol
Page 33 and 34: primaxillaries but are asymmetrical
Page 35 and 36: — 658 —At the same time, all th
Page 37 and 38: — 660 —AcknowledgementsThis art
Page 39 and 40: ROMAN F. (1897) - Recherches strati
Page 41 and 42: PLATE
Page 43: Geobiosn° 20, fasc. 5Pl. 1V.G. Kli

thiolliericrinid crinoids from the lower cretaceous of crimea

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