Palaeobiology and Biogeography of a Danian Echinoid Fauna of Lower Austria

Palaeobiology and biogeography of a Danian echinoid fauna of Lower Austria.

A. Kroh Institute of Geology and Palaeontology, Karl-Franzens-Uniersity, Graz, Austria

ABSTRACT: The echinoid fauna of the Danian (Paleocene) Bruderndorf Formation in Lower Austria is fairly diverse (19 taxa). A palaeoecological analysis based on functional morphology is carried out to assess the mode of living and feeding of the different species. The two preserved environments are dealt with separately and compared with each other. Finally the spatial distribution of the recorded species is investigated to improve our understanding of Danian echinoid biogeography.

Keywords: Echinoids, Paleocene, Europe, Functional Morphology, Palaeobiogeography

1 INTRODUCTION Table 1. List of taxa recorded from the Brudendorf Formation.

1.1 History Coralline Algal Limestone Facies Cidaridae indet. The Danian strata in Austria were discovered in the Hyposalenia heliophora (Agassiz & Desor, 1846) 1930s of the 20th century by M. Glaessner and subse- Sandstone Facies quently investigated by O. Kühn. Kühn (1930) Adelopneustes boehmi (Nietsch, 1921) reported 8 species of echinoids, 4 of which he consid- Adelopneustes montainvillensis (Sorignet, 1850) ered as new species. In the following decades much Adelopneustes aff. akkajensis (Endelman, 1980) material was collected and several new outcrops were Plagiochasma cruciferum (Morton, 1830) discovered. This material was never really investi- Holasteridae indet gated and only listed cursorily in a short paper on the Echinocorys scutata forma ovata (Leske, 1778) Paleocene strata of Austria (Kühn, 1960). A through- Echinocorys scutata forma pyrenaica Seunes, 1888 out revision of the echinoid fauna of these strata can Echinocorys scutata forma A be found elsewhere (Kroh, 2001). More than 1200 Echinocorys scutata forma B specimens were studied in this work and 19 species of Cyclaster aturicus (Seunes, 1888) echinoids could be recognized (see Tab. 1). Isaster aquitanicus (Grateloup, 1836) Hemiaster stella (Morton, 1830) Coraster vilanovae Cotteau, 1886 1.2 Geological Setting Orthaster dagestanensis Moskvin, 1982 Orthaster sp. The Danian strata of the Bruderndorf Formation crop Homoeaster evaristei (Cotteau, 1886) out in the north-eastern part of Austria, in the highly Corasteridae indet. heterogeneous Waschberg Zone (see Fig. 1). The Linthia cf. houzeaui Cotteau, 1878 Waschberg Zone comprises an incomplete sediment- ______tary succession from the Upper Jurassic to the Lower Miocene and is covered by Middle Miocene to The Danian age of the Bruderndorf Fm. was in- Pleistocene sediments. Outcrops tend to be small and ferred by Kühn (1930) on the base of the faunal con- patchily distributed. Material of all known outcrops tent. This age assignment was verified by Schmid of the Bruderndorf Fm. was used for this study; the (1962) using planktic foraminifers and Stradner majority of the specimens (more than 90 %), however, (1961, 1962) using calcareous nannoplankton. Ac- come from a single locality known as Haidhof near cording to Perch-Nielsen (1979) such a nannoplank- Ernstbrunn in Lower Austria. ton assemblage indicates a Late Danian age.

69 Although the echinoid diversity seems to be rela- tively poor in this environment at first glance, one has to consider the taphonomic bias for regular echinoids (Kier, 1977) and the sampling bias for this facies, which is not very well exposed. Additionally, they are well represented by disarticulated and in most cases heavily abraded, indeterminable ossicles. The coralline algal limestone facies overlies and laterally interfingers with the sandstone facies, however, due to the nature of the outcrop the exact nature of the contact remains largely unclear. The echinoid fauna comprises undetermined cidaroids and Hyposalenia heliophora. Of the cidaroids only interambulacral plates and spine fragments are available, but it may be assumed that they lacked well developed, conjugate isopores. An epifaunal omnivorous lifestyle, like those of most living cidaroids (Lawrence, 1975), is here interpreted for these animals. Hyposalenia heliophora has P1 and P2 isopores only and lacks oral phyllodes, thus being restricted to low to moderate energy environments and an omnivorous lifestyle (Smith, 1978). Both forms presumably fed on algae, bryozoans and other small invertebrates. Such animals usually prefer stable sedimentary bottoms, as represented by this facies.

2.2 Sandstone facies The sandstone facies is represented by moderately well sorted, glauconitic fine to medium-grained sand. This sediment is very fossiliferous, especially echi- Figure 1. Geological overview of northeastern Austria (modified from Fuchs, 1981). The small inset shows the noids are very abundant and are the most common exact location of the area. macrofossils found. They are far more abundant and diverse in this facies than in the other two preserved facies. The only other common fossils are small mol- Three lithofacies can be distinguished: lusks, but in far lower numbers than the echinoids. Furthermore, solitary corals, cephalopods, serpulids − fine sand facies and rarely plant remains can be found. − sandstone facies The echinoid fauna is rather diverse comprising 17 − coralline algal limestone facies taxa in total. Yet, despite the diversity, only 6 species dominate the fauna (see Fig. 2). First of all Cyclaster Echinoderm remains can be found in all three fa- aturicus, making up about 49% of all examined spec- cies. They are, however, most prevalent in the sand- imens. It is followed by Orthaster dagestanensis, stone facies and very rare in the fine sand facies. Echinocorys scutata forma pyrenaica, Echinocorys scutata forma ovata, Hemiaster stella and Coraster vilanovae. Most other taxa are accessory, being repre- 2 PALAEOECOLOGY sented by one or two specimens only and account for only about 2 % of the specimens. 2.1 Coralline Algal Limestone The different Adelopneustes species show an undifferentiated, uniserial arrangement of small, simple The coralline algal limestone facies is represented by ambulacral pores, which are arranged in weak triad pat- heterogeneous algal limestone with variable glauconite terns near the peristome There are no phyllodes and content. The sediment is composed mainly of coralline the peristome is obliquely oval and slightly sunken. algal debris, small rhodolithes, shell debris of mol- The tubercles are more or less symmetrical and the lusks and brachiopods and bryozoans. Echinoderm areoles are only slightly enlarged posteriorly. This pat- remains are common, but consist of disarticulated ossi- tern suggests that these species lack the adaptations for cles mainly. They include crinoids, ophiuroids, aster- continuous burrowing and unidirectional movement oids and echinoids.

70 Plagiochasma cruciferum has semipetaloid ambu-lacra incorporating pores for respiratory podia and a well developed, uniform spine canopy aborally, enabling it to burrow. The large periproct and the pres-ence of an anal sulcus indicate that the animal produced a large amount of fecal material. This fea- ture, the weakly developed phyllodes, and the sunken peri-stome suggest that Plagiochasma was an unselective bulk sediment swallower. All of the remaining irregular echinoids possess highly specialized pores arranged in phyllodes around the peristome. Such pores have presumably been asso- ciated with penicillate tube feet (Smith, 1980b) and all of the species discussed below are interpreted as deposit feeders using these penicillate tube feet for food collecting. In both Isaster aquitanicus and Homoeaster evaristei, the pores of ambulacrum III are very simi- Figure 2. Relative abundance of the echinoids of the Sandstone lar in size and structure to the pores of the paired facies. ambulacra and might have had respiratory function. No specialized pores for funnel-building tube feet are found in either species and thus they apparently lacked the ability to build either a respiratory shaft or (Smith, 1980a). They presumably used their oral drain. They are, however, clearly adapted for burrow- spines to excavate sediment from beneath themselves, ing, exhibiting a dense uniform aboral spine canopy enabling them to burrow vertically down, possibly and well developed apical fasciole in the case of for protection from predators and emerging periodi- Homoeaster. Both species seem to have led a shallow cally to forage. They might have fed on sediment burrowing infaunal life-style, having been restricted surface material using their tube feet. “Globator” to the uppermost level of the sediment. bleicheri (Gauthier) a very similar species from the Hemiaster stella exhibits many adaptations for a bur- Maastrichtian of the United Arabian Emirates-Oman rowing, infaunal life-style: a dense aboral spine canopy border region was interpreted as infaunal selective and a distinct wedge shape, enabling it to bur-row in particle feeder similar to the extant Echinoneus fine grained sediments; sunken paired petaloid ambu- cyclostomus Leske by Smith (1995). lacra, which must have had tube feet specialized for Echinocorys scutata and the undetermined holas- gaseous exchange; a broad peripetalous fasciole, ensur- terid are interpreted as semi-infaunal ploughers. ing a successful protection of the respiratory podia Echinocorys has a flat-based, domed test profile and through a mucus envelope; and specialized funnel- a uniform aboral spine canopy. It lacks a sunken frontal building tube feet in ambulacrum III. It lacked, how- ambulacrum and specialized tube feet for the construc- ever podia for the construction of a drain and thus tion of either respiratory shaft or drain. The aboral was probably restricted to the middle to upper part pores are similar in all five ambulacra and according to of the sediment. Morphological similar species of their structure seem to have had a respiratory function H. (Bolbaster) from the Cenozoic of Australia were (Smith, 1980b). The arrangement of the oral tubercles interpreted to having burrowed approximately 10 to suggests a unidirectional movement on the sediment 12 cm below the sediment/water interface (McNamara, surface. Obviously Echinocorys fed on organic detri- 1987). tus from the sediment surface, while ploughing along, Cyclaster aturicus likewise exhibits many of the using its enlarged, penicillate tube feet around its adaptations for burrowing listed for Hemiaster. In mouth for food collecting (Smith, 1980b, 1988). Only addition, it possessed specialized subanal tube feet for one heavily worn specimen is available of the unde- funnel-building, and must have been capable of con- termined holasterid species, which does not show structing a drain (Smith, 1980b, Jagt & Michels, 1994). sufficient details for a palaeoecological interpreta- Most specimens of this species, however, do not pos- tion. It is, however, very similar to the Cenomanian sess a peripetalous fasciole or more rarely show an species Holaster nodulosus (Goldfuss) and H. laevis incomplete one. This indicates that it was restricted (Brongniart), which have been interpreted as epifau- to the middle to upper part of the sediment as was nal to semi-infaunal living deposit feeders using their Hemiaster stella. penicillate tube feet to pick up underlying sediment Coraster vilanovae, Orthaster dagestanensis and particles by Smith (1988). Linthia cf. houzeaui are interpreted to have been deep

71 burrowers because of their ability to construct both a respiratory shaft and drain. All three species have a very shallow frontal notch and must have collected their food on the oral side mainly, using penicillate tube feet. The corasterids in particular have a globular, almost spherical, test shape, which is considered as specialization for deeper burrowing (Kanazawa, 1992).

2.3 Summary The echinoids derive from two different palaeoenvironments: a siliciclastic environment and a coralline algal-dominated carbonate environment. The silici- Figure 3: Schematic diagram of the habitat of the different clastic environment is dominated by burrowing and echinoid species. 1: Hyposalenia heliophora, 2: undetermined ploughing irregular echinoids, whereas the carbonate cidaroids, 3: Echinocorys div. sp., 4: Hemiaster stella, environment is dominated by epibenthic grazing reg- 5: Cyclaster aturicus, 6: Orthaster dagestanensis and ular echinoids, which might have used corallinaceae 7: Coraster vilanovae rhodoliths as secondary hardgrounds (see Tab. 2). The echinoid fauna of the siliciclastic environment is far more diverse (17 taxa), although, this might be in part an artifact due to a sampling bias in the hard lime- environmental conditions were especially favorable stone of the carbonate environment. Despite the high for some of the species (e.g. Cyclaster aturicus). diversity the fauna of the sandstone facies is domi- The palaeoecological analysis of the echinoid fauna, nated by several very abundant species, which occu- sedimentology and regional setting indicate an upper pied different levels within the sediment (spatial shelf setting with low water energy for the siliciclastic tiring; see Fig. 3). The diversity and abundance of environment. This corresponds well to the results of echinoids is controlled by competition (Nichols, 1959) Schmid (1962), who concluded a depositional depth of and ecological parameters (Ernst, 1970). In the present 100 to 200 meters for the fine sand facies, on the basis assemblage competition between the echinoid species of the foraminifer fauna. Data on the depositional was probably low due to spatial tiring. Obviously, the depth of the carbonate environment is inconclusive, but the fauna indicates a shallower setting than the one Table 2. Postulated feeding strategies of the echinoid species. inferred for the sandstone facies. The contact between ______the two facies is, as stated above, unclear. But consid- Coralline Algal Limestone Facies ering the heterogeneous nature of the study area, it is not surprising, that sediments of different depth and Epifaunal origin are found next to each other. Cidaridae indet. omnivores

Hyposalenia heliophora omnivores

Sandstone Facies 3 BIOGEOGRAPHY Semi-infaunal (ploughers) Echinocorys div. sp. deposit feeders using The Bruderndorf formation was deposited off the Holasteridae indet. penicillate tube feet south-eastern coast of the Bohemian Massif in a water Semi-infaunal (grazers) depth between 100 and 200 m, as inferred by a study of Adelopneustes div. sp. epipsammic grazer, possibly the planktic foraminifers by Schmid (1962). It lies at the emerging periodically to southern margin of central part of the European shelf forage (see Fig. 4). Prior to the revision of the Bruderndorf Infaunal (burrowers) Formation echinoids (Kroh, 2001) the fauna was Plagiochasma cruciferum bulk sediment swallower thought to be very peculiar with about 50% endemic deposit feeders using penicillate tube feet: species. This, however, is not true, since there are in fact Isaster aquitanicus shallow burrowers no endemic species. The supposed endemism of some Homoeaster evaristei shallow burrowers species was found to be just artifacts resulting from different taxonomic treatment. Hemiaster stella moderately deep burrowers The echinoids recorded in the Late Danian of Austria Cyclaster aturicus moderately deep burrowers are found all over the European shelf (see Fig. 4). Coraster vilanovae deep burrowers Strong ties exist to the fauna of South-western Europe, Orthaster dagestanensis deep burrowers as well as the Transcaspian region. But an equally _Li___nthi___a cf___. houzeau______i______d___eep___ bur___row___ers______strong northerly influence can also be observed. Some

Figure 4. Spatial distribution of the echinoid taxa recorded from the Bruderndorf Formation plotted on a palaeogeographic map of Peri-Tethys region during the Late Maastrichtian by Dercourt & al. (2000). The big white asterisk marks the location of the study area. The data on the spatial distribution of the echinoid species are taken from Smith & Jeffery (2000).

groups, as for example the corasterids, do not occur in 4 CONCLUSIONS the more northern regions, whereas in contrast to that Hyposalenia heliophora and Linthia houzeaui seem Two different palaeoenvironments, in which echinoids to be restricted to these regions. form an important part of the preserved macro-benthos The open ocean in the south seems to have acted as are represented by the sediments of the Bruderndorf a strong filter, only very few species also occurring on Fm. Each environment is characterised by its own the Northern African shelf. Some species, on the other peculiar echinoid fauna, which differ strongly both in hand, have a very broad spatial range and occur also in mode of living, as well as in feeding habit. In the deeper Greenland, the Eastern USA or Africa (see Tab. 3). sandy environment echinoids form the dominant group To quantify those data: 62 % respectively 54% of of benthic animals. Using functional morphology, it is the echinoids observed in the study area do also possible to infer the feeding and living modes of the occur in Northern Europe, the Transcaspian region different species, which indicates that the echinoid and the Pyrenean basin. Whereas only 7% occur also fauna of this environment showed spatial tiring, i.e. on the North African shelf. This data support the sep- that the different species facilitated different levels aration of a North-European Region from a Ancient- within the sediment, thus minimising competition Mediterranean Region in the Early Paleocene already. between species. A similar pattern was discovered for the Eocene benthos The echinoid fauna shows distinct affinities to the in general by Popov et al. (2001). The rather uniform North and Southwest European echinoid faunas, as distribution of species within the North-European well as to the faunas of the Caucasus and the Trans- Region, which represents a very large area, and the caspian region. This distribution supports the theory presence of some, albeit few, species from as far away of a major faunal reorganisation following the K/Pg- as the Eastern USA or Madagascar, support the theory event (Smith et al., 1999), which resulted in a rather of a major faunal reorganization following the K/T homogeneous and widely distributed echinoid fauna event, as claimed by Smith et al. (1999). during the Danian. On the other hand it clearly shows, 73 Table 3: Overview of the geographic distribution of echinoid taxa recorded from the Late Danian Bruderndorf Formation of Austria.

that the distribution patterns of benthic animals as Ernst, G. 1970. Faziesgebundenheit und Ökomorphologie reconstructed for the Eocene was already established bei irregulären Echiniden der nordwestdeutschen Oberkrei- as early as the Late Danian. de. Paläontologische Zeitschrift 44(1-2): 41-62. Fuchs, W. 1981. Großtektonische Neuorientierung in den Ostalpen unter Einbeziehung plattentektonischer Gesichtspunkte, 1:1,500.000. Beilage zur Geologischen 5 ACKNOWLEDGEMENTS Karte von Wien und Umgebung 1:200.000, Geologische Bundesanstalt, Wien. I want to thank Kenneth McNamara and Didier Jagt, J.W.M. & Michels, G.P.H. 1994. The palaeobiology of Néraudeau for their critical reviews and improving a late Maastrichtian echinoid fauna from Haccourt (Liège, NE Belgium). In: B. David, A. Guille, J.-P. Féral. & comments. Furthermore, I want to thank the following M. Roux (eds.), Echinoderms through Time; Proc. of the people for their help and support during the prepera- 8th Internat. Echinoderm Conf. Dijon/France, 6-10 Sept. tion of this paper: Mathias Harzhauser (NHM Vienna), 1993: 719-724. Rotterdam: Balkema. Jaume Gallemí (Museo de Geologia, Barcelona), Kanazawa, K. 1992. Adaptation of test shape for burrowing John W. M. Jagt (NHM Maastricht), Werner Piller and locomotion in spatangoid echinoids. Palaeontology 35(4): 733-750. (Karl-Franzens-Univ., Graz), and the staff of the Kier, P.M. 1977. The poor fossil record of the regular echin- Natural History Museum Vienna. oid. Paleobiology 3(2): 168-174. Kroh, A. 2001. Echinoids from the Danian (Lower Paleocene) Bruderndorf Formation of Austria. In: W.E. Piller & M.W. Rasser (eds.): Palaeogene of the Eastern Alps. Öster- REFERENCES reichische Akademie der Wissenschaften, Schriftenreihe der Erdwissenschaftlichen Kommissionen Dercourt, J., Gaetani, M., Vrielynck, B., Barrier, E., Biju- 14: 377-463. Duval, B., Brunet, M.F., Cadet, J.P., Crasquin, S. & Kühn, O. 1930. Das Danien der äusseren Klippenzone bei Sandulescu, M. (eds.) 2000. Atlas Peri-Tethys. Paris: Wien. Geologische und Palaeontologische Abhandlungen, Commission for the Geological Map of the World. Neue Folge 17(5): 495-576.

74 Kühn, O. 1960. Neue Untersuchungen über die Dänische Smith, A.B. 1978. A functional classification of the coronal Stufe in Oesterreich. - Rept. XXI. Int. Geol. Congr. 5: pores of regular echinoids. Palaeontology 21(4): 759-789. 162-169, København. Smith, A.B. 1980a. The structure and arrangement of echi- Lawrence, J.M. 1975. On the relationship between marine noid tubercles. Philosophical Transactions of the Royal plants and sea urchins. Oceanography and Marine Society of London (B) 289: 1-54. Biology 13: 213-286. Smith, A.B. 1980b. The structure, function, and evolution of McNamara, K. 1987. Taxonomy, Evolution, and Functional tube feet and ambulacral pores in irregular echinoids. Morphology of Southern Australian Tertiary Hemiasterid Palaeontology 23(1): 39-83. Echinoids. Palaeontology 30(2): 319-352. Smith, A.B. 1988. Echinoids. In: A.B. Smith, C.R.C. Paul, Nichols, D. 1959. Changes in the Chalk Heart-Urchin A.S. Gale & S.K. Donovan (eds.). Cenomanian and Lower Micraster interpreted in Relation to living Forms. Philo- Turonian echinoderms from Wilmington, south-east Devon, sophical Transactions of the Royal Society London (B) 242: England. Bulletin of the British Museum (Natural History), 347-437. Geology Series 42: 16-189. Perch-Nielsen, K. 1979. Calcareous nannofossil zonation Smith, A.B. 1995. Late Campanian-Maastrichtian echinoids at the Cretaceous/Tertiary boundary in Denmark.- In: from the United Arab Emirates-Oman border region. T. Birkelund & R.G. Bromley (eds.), Cretaceous-Tertiary Bulletin of the Natural History Museum, Geology Series Boundary Events Symposium I: The Maastrichtian and 51(2): 121-240. Danian of Denmark: 115-135, Copenhagen: University Smith, A.B., Gallemí, J., Jeffery, C.H., Ernst, G. & Ward, P.D. of Copenhagen. 1999. Late Cretaceous-early Tertiary echinoids from Popov, S.V., Akhmetiev, M.A., Bugrova, E.M., Lopatin, A.V., northern Spain: implications for the Cretaceous-Tertiary Amitrov, O.V., Andreeva-Grigorovich, A.S., Zherikhin, V.V., extinction event. Bulletin of the Natural History Museum, Zaporozhets, N.I., Nikolaeva, I.A., Krasheninnikov, V.A., Geology Series 55(2): 81-137. Kuzmicheva, E.I., Sytchevskaya, E.K. & Shcherba, I.G. Smith, A.B. & Jeffery, C.H. 2000. Maastrichtian and 2001. Biogeography of the Northern Peri-Tethys from the Palaeocene echinoids: a key to world faunas. Special Late Eocene to the Early Miocene: Part 1. Late Eocene. Papers in Palaeontology 63: 1-406. Paleontological Journal 35, Suppl. 1: S1-S68. Stradner, H. 1961. Vorkommen von Nannofossilien im Schmid, M.E. 1962. Die Foraminiferenfauna des Mesozoikum und Alttertiär. Erdöl-Zeitschrift 77(3): 77-88. Bruderndorfer Feinsandes (Danien) von Haidhof bei Stradner, H. 1962. Bericht 1961 über die Aufsammlungen Ernstbrunn, NÖ. Sitzungsberichte der Österreichischen A- von mesozoischen und alttertiären Nannoplankton- kademie der Wissenschaften Wien, Mathematisch- materialien aus der Waschbergzone (Niederösterreich). naturwissenschaftliche Klasse, Abteilung I 171(8-10): Verhandlungen der Geologischen Bundesanstalt 1962(3): 316-361. A106-A107.