Contr. Tert. Quatern. Geol. 30(1-2) 41-73 15 figs, 4 tabs, 4 pis. Leiden, June 1993 Early Danian species of the echinoid genus Tylocidaris (Cidaridae, Psychocidarinae) from eastern Denmark Palle Gravesen Geological Museum Copenhagen, Denmark Palle. Danian of the echinoid from Denmark. — Contr. Gravesen, Early species genus Tylocidaris (Cidaridae, Psychocidarinae) eastern Tert. Quatern. Geol., 30(1-2): 41-73, 15 figs, 4 tabs, 4 pis. Leiden, June 1993. of the echinoid 1883 were used index fossils for the Danian Primary spines genus Tylocidaris Pomel, formerly widely as key (Early In their value such has been discredited and distribution has been shown be Palaeocene). recent years as tylocidarid species to diachronous in relation todinoflagellatebiostratigraphy as well as be facies-dependentto the extent that they are missing from important facies of Difficulties in correlation between the Danian of Denmark and southern Sweden have types the Danian. establishing a strata also affected their practical use. A biostratigraphical study based onspecimens collected bed by bed at Stevns Klint and additional studies localities situated in the Danian have evidence that the at Karlstrup quarry (both Stage type area, eastern Denmark), provided Early Danian tylocidarid zonation of Denmark and southern Sweden is essentially the same with T. oedumi Brünnich Nielsen, 1938 and T. for Limhamn abildgaardi Ravn, 1928 being restricted to two distinct zones, and thus not co-occurring as suggested by Brotzen (1959) the locality in Sweden. One major discrepancy between the Danish and Swedish biozonation schemes has thus been eliminated. Material collected shows that Middle Danian rosenkrantzi Zone is that this been at Karlstrup quarry an early present at locality, zone not having recorded from Denmark far. collected material of T. oedumi and T. so Especially interesting amongst newly are tests abildgaardi. Finally, bryozoan mound growth is discussed. It is suggested that the growth ofEarly Danian mounds was affected by palaeocurrents which swept sediment from thus formation take there. The have existed for a away intervening troughs, allowing hardground to place troughs must considerable time At Stevns shows series ofconsecutive In the span. Klint, alarge trough structure an impressive (incipient) hardgrounds. bryozoan mounds, net growth rate is shown to have been rather slow, allowing typical T. oedumi to evolve via ’overlap forms’ to T. the formation of the first series ofmounds. A model for evolution in the Danian is with abildgaardi during new tylocidarid type proposed, the lineage oedumi- -’overlap forms’-abildgaardi-ravni-bruennichi becoming extinct in the late Middle Danian, then being replaced by vexilifera, from originating a lineageoedumi-rosenkrantzi-vexilifera. — Key words Danian, biozonation, Cidaridae (Psychocidarinae), Tylocidaris, evolution, bryozoan mounds, Denmark, Sweden. P. Gravesen, Geologisk Museum, 0ster Voldgade 5-7, DK-1350 Copenhagen K, Denmark. Contents mark and southern Sweden. Although still very use- doubts their index ful, as to importance as fossils Introduction 41 p. have recently been expressed, their place being of biozonation 42 History tylocidarid p. taken by micro- and/or nannofossils such as for- Localities 43 p. aminifera, dinoflagellates and calcareous nanno- Methods 47 p. plankton. Systematic descriptions p. 49 Two factors have contributed to this situation: Conclusions p. 56 — the conclusion that their geographical distribu- 56 Phylogeny p. tion is diachronous in relation to dinoflagellate bio- Patterns of bryozoan mound growth p. 61 zonation (Hansen, 1977), being evidently facies Acknowledgements p. 64 that dependent to the extent they are missing from References 64 p. facies of the many important Danian; — difficulties related to the definition and identi- fication of within the Introduction species genus. The work Danian is that For a long time tylocidarids, i.e. the disarticulated most recent on tylocidarids of various of primary spines species the genus of Brotzen (1959), who presented a detailed bio- have been considered zonation for the Limhamn Tylocidaris Pomel, 1883, quarry (Skane, SW important key index fossils for the Danian of Den- Sweden) comprising the following zones: 42 Tylocidaris herupensis (= Late Danian) [top] Danian. Rosenkrantz (1965) presented compelling the Zone arguments in support of view that Schliiter's Tylocidaris briinnichi (= late Middle Danian) specimens must have come from the former quarry Zone at Herfolge, south of Koge (eastern Sjaelland) and rosenkrantzi Middle thus must be of Late Danian Tylocidaris (= early Danian) age. Zone In 1909, Brtinnich Nielsen was the first to point Tylocidaris oedumi (= Early Danian) out that the various forms of T. vexilifera Schltiter in the Danian be useful index Zone [bottom] occurring might as fossils. It was not until 1926 that 0dum subdivided A similar, but different, zonation had already been Schliiter's species into three 'forms', viz ■ forma beta established in Denmark by Brtinnich Nielsen (1938), (= T. vexilifera Schliiter, 1892 s. str.), forma alpha (= amended Rosenkrantz & T. and forma T. which was subsequently by abildgaardi Ravn, 1928), gamma (= Wienberg Rasmussen (1960) as follows: oedumi Briinnich Nielsen, 1938). Ravn (1928) proposed the following division of Tylocidaris vexillifera (= Late Danian) [top] Schliiter's species: forma typica (= T. vexilifera Zone Schliiter, 1892 s. str.), var. Brünnichi (= T. bruennichi Tylocidaris bruennichi (= Middle Danian) Ravn, 1928), and var. Abildgaardi (= T. abildgaardi Zone Ravn, 1928 and T. oedumi Briinnich Nielsen, 1938). Ravn's Brünnichi introduced and Tylocidaris abildgaardi (= late Early Danian) var. was newly is Zone now known to characterise the Middle Danian. In Tylocidaris oedumi (= early Early Danian) his var. Abildgaardi, Ravn grouped not only the Early Danian known under that but Zone [bottom] species now name also 0dum's forma T. (1926) gamma (= oedumi). Since their introduction, differences between these Later, Briinnich Nielsen (1938) presented the fol- correlations zonation: zonations have frustrated based on lowing tylocidarids between the Swedish and Danish Dan- Late Danian ian and have contributed to the view that bio- Tylocidaris vexilifera Schliiter based hitherto useful Ravn, stratigraphical dating on spe- (.sensu 1928) cies of this is with difficulties. Tylocidaris bruennichi Ravn, genus fraught 1928 The discrepancies between Brotzen's (1959) Danian zonation and the Danish zonal scheme were the Early Tylocidaris abildgaardi Ravn, 1928 main reason for a renewed investigation reported in the of Tylocidaris oedumi Briinnich upon herein, hope shedding new light on Nielsen, 1938 on forma some of the main problems. However, many ques- (based tions since the 0dum, remain, especially present paper gamma 1926) focuses Danian only on Early tylocidarids. Middle and Late Danian should be stud- This zonation also used in tylocidarid species new was the virtually ied in the along similar lines (near) future. simultaneous Rosenkrantz the paper by (1938) on stratigraphy and tectonics of the Danian of eastern Wind without Sjaelland. (1953, 1954), any justifica- HISTORY OF TYLOCIDARID BIOZONATION tion, referred T. oedumi to the late Turonian-?late the of this Santonian T. sub- At beginning century, only a single spe- (T.) clavigera (Mantell, 1822) as a cies of T. and T. T. bruennichi and Tylocidaris, vexilifera Schltiter, 1892, was species abildgaardi, T. vex- recorded from the Danian. Ever since its erection, ilifera to the Campanian-Maastrichtian T. pomifer this species has presented problems. To start with a (Leymerie, 1851) [now referred to the genus Sar- Schltiter docidaris Smith minor point: (1892, p. 126 [54], pi. 17, figs Lambert, 1907; see & Wright, 1989] the trivial while also T. T. Brünnichi 3, 4) spelt name as vexilifera, many as subspecies, viz. p. pomifer, p. palaeontologists after him have preferred vexillifera. and T. p. herupensis Wind, 1954, respectively. Wind's Much more serious confusion arose from the fact taxonomy has not been adopted by later workers, that Schltiter stated that his species originated from with the exception of Brotzen (1959), who used the Maastrichtian white chalk of Stevns the Klint, name Tylocidaris herupensis Wind, 1954 for T. vex- which is an error, the species being typical of the ilifera Schliiter, 1892. 43 Brotzen's the biozonation of resolve the between eastern Denmark paper on tylocidarid discrepancies the Danian of Limhamn is of prime importance; and southern Sweden. Two localities in eastern windi Denmark three new species were erected, viz■ T. (Early (Karlstrup and Stevns Klint) were selected T. and T. ravni Mid- for this and with Limhamn Danian), rosenkrantzi (both early purpose, compared (SW dle the sides the 0resund. All three Danian). According to Brotzen, Danian of Sweden) on opposite of Limhamn shows the in localities situated in the of the Danian following pattern tylocidarid are type area and distribution: Stage (compare Brotzen, 1959, fig. 1) are thus of prime importance in biostratigraphical studies of — Late Danian herupensis Zone the type Danian. Detailed descriptions and sections T. of Limhamn [species represented: quarry may be found in Brood (1973), herupensis (= T. Cheetham (1971), Holland& Gabrielson (1979) and vexilifera)] Holland (1982). — late Middle Danian bruennichi Zone T. [species represented: LOCALITIES bruennichi] 1. — Karlstrup early Middle Danian rosenkrantzi Zone quarry [species represented: T. The