BioOne.org will be down briefly for maintenance on 17 December 2024 between 18:00-22:00 Pacific Time US. We apologize for any inconvenience.
Open Access
How to translate text using browser tools
13 December 2013 Mammal-Like Tooth from the Upper Triassic of Poland
Marlena Świło, Grzegorz Niedźwiedzki, Tomasz Sulej
Author Affiliations +
Abstract

Recent Triassic discoveries have extended the record of near-mammals (Mammaliaformes) back to the Norian, about 215 Ma, and reveal a significant diversity of Late Triassic (Norian-Rhaetian) forms. We now add to this Late Triassic diversity a nearly complete double-rooted right lower molariform tooth (ZPAL V.33/734) from the Polish Upper Triassic that is significant because it comes from uppermost Norian—lower Rhaetian rocks and is the first discovery of a mammal-like tooth in the Mesozoic of Poland. The described tooth shows transitional dental morphology between advanced cynodonts and mammaliaforms and it appears to represent a basal mammaliaform (genus Hallautherium), probably belonging to Morganucodonta.

Introduction

Mammal (sensu Kielan-Jaworowska et al. 2004) or mammaliaform (sensu Luo 2007) remains (mainly teeth) are known from numerous sites within Upper Triassic rocks, mainly in Western Europe, but also in Greenland and India. Collectively, these sites span the Norian through the end of the Rhaetian (see Clemens 1980, 1986; Datta and Das 1996; Kielan-Jaworowska et al. 2004; Datta 2005; Kemp 2005; Luo 2007). The latest Triassic mammaliaform faunas come from very different environments (e.g., lacustrine, deltaic, marginal-marine) and generally differ in composition and are usually dominated by, or solely contain, the remains of morganucodontids. Most of the Norian sites are dominated by remains of Haramiyida.

The most fossiliferous are Upper Triassic sites from continental Europe (Germany, France, Belgium, Switzerland, Luxemburg), but very important discoveries come from the Upper Triassic-Lower Jurassic fissure deposits of England and Wales, the lower part of the Tiki Formation in India, and Upper Triassic rocks of Jameson Land (Greenland) (see Kielan-Jaworowska et al. 2004; Datta 2005).

According to the fossil record from the Late Triassic and Early—Mid Jurassic, the diagnostic osteological features that have traditionally been associated with modern mammals did not evolve together at the same time (Luo 1994, 2007, 2011; Sidor and Hopson 1998; Kielan-Jaworowska et al. 2004; Rowe et al. 2011). A few features traditionally regarded as “mammalian” first appeared in the Late Triassic among their proximal relatives amidst the Mammaliaformes and Mammaliamorpha, while other derived characters appeared for the first time only among Jurassic mammals. It is also clear that some mammalian features have precursor conditions among derived cynodonts. Hence, the affinities of incomplete fossils are often difficult to assess. This applies especially to the teeth, which are very similar in morphology in basal mammaliamorphs (e.g., Brasilodon, Brasilitherium) and mammaliaforms (e.g., Sinoconodon, Morganucodon, Hadrocodium), and which presumably also are similar in the ancestor of Mammalia (Luo et al. 2001; Bonaparte et al. 2005; Luo 2007). However, basal mammaliamorphs teeth have less divided roots and undifferntiated postcanines.

Here we describe an isolated right lower molariform tooth of a probable early representative of mammaliaform, most likely morganucodontid (basal mammaliaforms), which comes from the Upper Triassic (Keuper) deposits of Poland. The specimen came from the lower part of the so-called grey unit, which is rich in plant and vertebrate remains and is exposed in a few places in the Lipie Śląskie clay-pit at Lisowice, Silesia, southern Poland (Fig. 1). The tooth was collected from this site in 2009 as part of a rock sample collected for the analysis of small fish fossils. Although isolated, this specimen deserves a short description in the literature, because it is consistent with morphology of mammaliaforms known from the Late Triassic and Early Jurassic elsewhere.

In the following description we adopt the terminology proposed by Crompton and Jenkins (1968) and used by other authors (e.g., Kielan-Jaworowska et al. 2004; Clemens 2011).

Institutional abbreviations. —PIMUZ, Paläontologisches Institut und Museum der Universität Zürich, Switzerland; SMNS, Staatliches Museum für Naturkunde, Stuttgart, Germany; ZPAL, Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland.

Geological and stratigraphic setting

The strata exposed in the Lipie Śląskie clay-pit at Lisowice correspond to the uppermost part of the Middle and lower part of the Upper Keuper deposits of the Germanic Basin (Aigner and Bachman 1992; Szulc et al. 2006; Franz et al. 2007a, b; Franz 2008; Dzik et al. 2008a, b). The lithostratigraphic unit represented at the Lipie Śląskie clay-pit has traditionally been referred in the geological literature to the Norian (see Szulc et al. 2006) or to the Rhaetian “sensu polonico” (Haisig et al. 1983; Franz et al. 2007a, b; Franz 2008).

The vertebrate macrofossil assemblage from the Lipie Śląskie clay-pit consists mainly of terrestrial rather than amphibious or aquatic tetrapods (Dzik et al. 2008a, b; Niedźwiedzki et al. 2011, 2012). Remains of a huge dicynodont are the most abundant finds and are followed by remains of the large predatory archosaur Smok wawelski, small to medium-size archosaurs (dinosauromorphs, dinosaurs, and poposaurids) and other archosauromorphs. Temnospondyls (Cyclotosaurus sp. and Gerrothorax sp.) are known from isolated, partially preserved skulls, skull bones, jaw bones, and numerous long bones. Like other bone-bearing sites of the Keuper unit in the Germanic Basin, the microfossils are dominated by remains of aquatic vertebrates and are comprised primarily of scales (or other dermal elements) and teeth of Actinopterygii, along with teeth, dermal denticles and fin spines of small sharks of the genera Polyacrodus and Hybodus (Świło 2010ac; Świło and Kowalski 2011). The only entirely aquatic macrofossils include numerous dental plates and skeletal elements of dipnoan fish (Dzik et al. 2008a). Other macrofossils represent mainly bones of land tetrapods.

Fig. 1.

A. Stratigraphic section of the Lipie Śląskie clay-pit at Lisowice. B. Location of the horizon that yielded ZPAL V.33/734, inset map showing position of locality in Poland.

f01_815.jpg

Lithic characteristics and identification of palynomorphs: Alisporites toralis (Leschik) Clarke, 1965, Todisporites cinctus (Malliavkina) Orłowska-Zwolińska, 1971, T. minor Couper, 1958, Anapiculatisporites spiniger (Leschik) Reinhardt, 1962, Anapiculatisporites telephorus (Pautsch) Klaus, 1960, Baculatisporites sp., Verrucosisporites sp., Foveolatitriletes crassus Orłowska-Zwolińska, 1983, Brachysaccus neomundanus (Leschik) Mädler, 1964, Ovalipollis sp. div., Cedripites microreticulatus Orłowska-Zwolińska, 1972, Ricciisporites tuberculatus Lundblad, 1954, Rhaetipollis germanicus Schulz, 1967, Classopollis classoides (Pflug) Pocock and Jansonius, 1961, Labiisporites triassicus Orłowska-Zwolińska, 1983, Enzonalasporites sp. div., Triadispora polonica Brugman, 1979, Triadispora sp., Monosulcites minimus Cookson, 1947, Taurocusporites verrucatus Schulz, 1967, Porcellispora longdonensis (Clark) Scheuring, 1970, cf. Carnisporites megaspiniger Morbey, 1975, Eucommiidites sp., Nevesisporites limatulus Playford, 1965, Corollina meyeriana (Klaus) Venkatachala and Góczán, 1964, Granuloperculatipollis rudis Venkatachala and Góczán, 1964, in the grey and organic-rich strata at the Lipie Śląskie clay-pit suggest correlation of this unit with the uppermost Zbąszynek Beds and lower Wielichowo Beds (uppermost Norian-lower Rhaetian) from the northern part of Poland (Orłowska-Zwoliń ska 1983; Deczkowski 1997; Franz 2008). This lithostratigraphic unit apparently continues into the upper Löwenstein, Trossingen, and Exter formations of the Middle-Upper Keuper (upper Norian- Rhaetian) in the east German part of the Germanic Basin (see Franz et al. 2007a, b; Franz 2008), which contains the geologically oldest fossils of early mammaliaforms in the Germanic Basin (Clemens 1980; Kielan-Jaworowska et al. 2004; Seegis 2005).

Fig. 2.

SEM microphotographs of ZPAL V.33/734, right lower molariform tooth of the morganucodont mammaliaform Hallautherium sp. from Upper Triassic, Lipie Śląskie clay-pit at Lisowice, Poland; in lingual (A), labial (B), and occlusal (C) views. Scale bars 500 μm.

f02_815.jpg

According to lithologic descriptions of boreholes from central Poland (Dadlez and Kopik 1963; Deczkowski 1997) this unit is characteristic for the upper Zbąszynek and lower Wielichowo Beds from the north-western and central parts of Poland (Franz et al. 2007a, b; Franz 2008; Pieńkowski et al. 2012), and is also similar in part to a local informal lithostratigraphic unit named the Woźniki Formation from the Solarnia IG-1, Silesia (see Haisig et al. 1983). Such a simple lithostratigraphic correlation is also consistent with biostratigraphic (palynomorph data) correlation of the Lipie Śląskie exposure with boreholes from the Polish Lowland.

Suggestive of latest Norian-early Rhaetian age are finds of cuticle fragments of the typical Rhaetian seed-fern Lepidopteris ottonis (Goeppert, 1836) (Staneczko 2007); the conifer Stachyotaxus septentrionalis (this genus has a distribution strongly restricted to the Rhaetian of Scania and Greenland; see Taylor et al. 2009); the isoëtalean macrospores Trileites cf. pinguis (Harris, 1935) and Horstisporites bertelseni Fuglewicz, 1977 (Fuglewicz 1977; Fuglewicz and Śnieżek 1980); and the conchostracans Gregoriusella polonica Kozur, Niedźwiedzki, and Sulej, 2010, Euestheria sp., and Shipingia sp. (Kozur and Weems 2010). The species G. polonica is known from the lower Exter Formation of northern Germany (early Rhaetian) and the upper Redonda Formation of New Mexico, occurring above the Shipingia olseni Zone, correlated with the late Norian (Kozur and Weems 2010).

Systematic palaeontology

Mammaliaformes Rowe, 1988
Order Morganucodonta Kermack, Mussett, and Rigney, 1973
Family incertae sedis
Genus Hallautherium Clemens, 1980

  • Type species: Hallautherium schalchi Clemens, 1980; Hallau, Kanton Schaffhausen, Switzerland, Rhaetian.

  • Hallautherium sp.

  • Material. ZPAL V.33/734 (lower molariform) from Upper Triassic, Lipie Śląskie clay-pit at Lisowice, Silesia, southern Poland.

  • Description.-ZPAL V.33/734 is a very small, but nearly complete double-rooted right lower molariform with a main row of three (or even four, specimen is incomplete) cusps and additional anterior and posterior lingual cusps (Fig. 2). The mesio-distal length of the crown is 1.3 mm and the maximum width is 0.48 mm (Fig. 3). The height of the whole tooth, including roots is 3.19 mm. Tooth is in the size range of Morganucodon watsoni, Hallautherium schalchi, and Morganucodon peyeri. Its crown is clearly laterally compressed and primary cusps (a-c) are arranged longitudinally (Fig. 3). It is lower molariform, because the principal cusps a, b, and c are in line and the cusp a, the highest, is positioned slightly mesial to the middle of the crown. Additionally, cusp c is much larger than cusp b. Typically, in lower molariforms of Morganucodontide, cusp g is large and situated lingual to the apex of cusp a, but in described specimen supposed cusp g is very small and situated lingual to the apex of cusp c.

    The central cusp (cusp a), which is slightly flattened labio- lingually, is more massive than the mesial and distal ones and is slightly inclined distally. At the apex there is a small circular wear facet (Fig. 2). Crests run down from the apex, anteriorly toward cusp b and posteriorly toward the groove separating the main cusp from cusp c. The posteriorly-inclined crest is more pronounced. The distolingual part of cusp a is concave and shows wear (Fig. 2). In the specimen ZPAL V.33/734 the principal cusp (a) is anterior to the midpoint of the crown length. Cusp b is conical and much smaller and lower than cusp a. It is located on the anterior part of the tooth. Mesio-lingual to cusp b is the slightly smaller cusp e, which is visible only on the lingual side. Cusp c is larger, and set much higher than cusps b and e. It is also closer to cusp a, separated from the cusp a by a shallow groove. It is cracked at the base in its distal part. Two crests run down from the top of cusp c. Just below cusp c, on the lingual surface, a small additional cusp is visible and most likely represents a poorly developed cusp g (Fig. 2). There is a small part chipped off at the distal edge of ZPAL V.33/734 (Fig. 3) where another small cusp (cusp d) may originally have been present. Neither surface (labial or lingual) of the lower part of the crown possesses a clearly marked cingulum, which supports identification of the specimen as a molariform of Hallautherium. As in Hallautherium schalchi but unlike any known morganucodontids a distal labial basin is present on ZPAL V.33/734 (in the form of a small depression on the described specimen). The roots are arranged mesio-distally and are massive at the base of the crown. They are very long and well separated, with a characteristic division up to the crown base (Fig. 3). Both roots are oval in outline. Pulp canals are open and the roots draw near each other at the ends.

    ZPAL V.33/734 does not contain a cingulum, which is generally poorly developed in the molariforms of basal mammaliaforms, but is a characteristic feature of morganucodontid molariform teeth (e.g., Mills 1971; Kermack et al. 1973; Clemens 1980; Sigogneau-Russell 1983a, b; Hahn et al. 1991). ZPAL V.33/734 lacks a distinct system of wear facets and there is no evidence that this molariform was interlocked with an opposing tooth.

  • Fig. 3.

    Explanatory drawing of ZPAL V.33/734, right lower molariform tooth of the morganucodont mammaliaform Hallautherium sp. (occlusal view) from Upper Triassic, Lipie Śląskie clay-pit at Lisowice, Poland.

    f03_815.jpg

    Discussion

    In contrast to advanced non-mammalian cynodonts, and like in the molariforms of basal mammaliamorphs (e.g., Brasilitherium) and early mammaliaforms such as Hallautherium, Morganucodon (e.g., Mills 1971; Kermack et al. 1973; Clemens 1980) or Megazostrodon (Crompton 1974; Gow 1986), ZPAL V.33/734 possesses cusps a-b-c-?-e (and also small cusp g). Presence of the cusp d is problematic because the fossil is broken. Additionally, ZPAL V.33/734 has roots that are more greatly separated from each other than in any known non-mammaliaform mammaliamorph cynodonts, and also has a distinct root division up to the crown base, which is unique for teeth of Mammaliaformes.

    The crowns of the lower molariforms of Hallautherium schalchi (specimens PIMUZ AIII-318 and AIII-337; see Clemens 1980) and in the lower molariform ZPAL V.33/734 are dominated by the relatively high principal cusp a, situated anterior to the midpoint of the crown. In addition, in Hallautherium schalchi and in the specimen ZPAL V.33/734 the two accessory cusps the posterior (c) is distinctly larger. All three teeth appear to have been supported by two, well separated roots.

    The key similarity between Hallautherium and the specimen ZPAL V.33/734 is the well development of the disto-labial basin on the lower molariforms. In addition, presence of such a labial basin, which appears to have occluded with a cusp(s) of an upper molariform, is unknown in any species of Morganucodon, Erythrotherium, Megazostrodon, or Eozostrodon (Clemens 1980).

    We consider ZPAL V.33/734 as an early mammaliaform molariform tooth (genus Hallautherium, order Morganucodonta; based on the following characters: 1, double-rooted tooth; 2, primary cusps a-c with additional cusp e and probably cusps d and g; 3, long and well separated roots with division close to the crown base; 4, presence of the disto-labial basin on the lower molariform; 5, cusp b is smaller than cusp c; and note that it has morphological features that distinguish it from teeth of all advanced non-mammalian cynodonts and basal mammaliamorphs (e.g., tritheledontids, tritylodontids, probainognathids, brasilodontids, and dromatheriids). Double-rooted teeth and well separated roots do not occur in early mammaliamorphs, which have incipient root division. However, Brasilodon and Brasilitherium have teeth that show root with a groove, which could possibly be an early stage of a double-rooted tooth formation. The lower postcanines of brasilodontids bear a large central cusp a flanked forward and backward by smaller, almost equal cusps b and c, which are arranged in mesio-distal line.

    ZPAL V.33/734 shows a dental morphotype characteristic for representatives of morganucodontids and genus Hallautherium (Clemens 1980, 2011; Sigogneau-Russell 1983a, b; Hahn et al. 1991). This isolated tooth discovery probably represents a new taxon of Late Triassic (latest Norian-early Rhaetian in age) morganucodontid, but based on such an isolated tooth specimen it is not possible to describe a new species.

    ZPAL V.33/734 is similar in age to the oldest fossils of morganucodontids in the Germanic Basin (they are latest Norian- Rhaetian in age) and is younger than the oldest fossils of dromatheriids, which are from the Turkey Branch Formation in Virginia (see Clemens 1980; Lucas et al. 2001), brasilodontids, which are late Carnian-early Norian in age (Bonaparte et al. 2005; Bonaparte 2013), and an isolated mammal-like tooth of an advanced cynodont (specimen SMNS 80766) from the Carnian of the Germanic Basin (Lucas et al. 2001). This find is significant as it is the first evidence of a mammaliaform taxon in the Upper Triassic deposits of the easternmost part of the Germanic Basin and it is also the second discovery of a mammalian fossil (and the first osteological specimen) in the Mesozoic of Poland (see Gierliński et al. 2004).

    Acknowledgements.

    We thank Zofia Kielan-Jaworowska (Institute of Paleobiology, Warsaw, Poland) and Richard L. Cifelli (Department of Biology, University of Oklahoma, Norman, USA) for discussions. We thank also all students, amateurs, and professionals, who participated in the excavations in the Lipie Śląskie clay-pit at Lisowice. We are also grateful to the following staff members of the Institute of Paleobiology, Polish Academy of Sciences in Warsaw: Cyprian Kulicki for SEM micrographs and Marian Dziewiński for help during fieldworks. Our fieldwork was supported by the Polish scientific funds as the project No. 2012/07/B/NZ8/02707 (grant to TS) and No. 3941/B/ P01/2009/36 (grant to GN). They were also supported by a special grant from the National Geographic Polska (2008–2009). Richard L. Cifelli and Pamela Gill (University of Bristol, UK) revised the manuscript.

    References

    1.

    T. Aigner and G.H. Bachmann 1992. Sequence-stratigraphic framework of the German Triassic. Sedimentary Geology 80: 115–135. Google Scholar

    2.

    J.F. Bonaparte 2013. Evolution of the Brasilodontidae (Cynodontia-Eucynodontia). Historical Biology 25: 643–653. Google Scholar

    3.

    J.F. Bonaparte , A.G. Martinelli , and C.L. Schultz 2005. New information on Brasilodon and Brasilitherium (Cynodontia, Progainognathia) from the Late Triassic of southern Brazil. Revista Brasileira de Paleontologia 8: 25–46. Google Scholar

    4.

    W.A. Clemens 1980. Rhaeto-Liassic mammals from Switzerland and West Germany. Zitteliana, Abhandlungen der Bayerischen Staatssammlung für Paläontologie und Historische Geologie 5: 51–92. Google Scholar

    5.

    W.A. Clemens 1986. On Triassic and Jurassic mammals. In : K. Padian (ed.), The Beginning of the Age of Dinosaurs , 237–246. Cambridge University Press, Cambridge. Google Scholar

    6.

    W.A. Clemens 2011. New morganucodontans from an Early Jurassic fissure filling in Wales (United Kingdom). Palaeontology 54: 1139–1156. Google Scholar

    7.

    A.W. Crompton 1974. The dentition and relationships of the southern African Triassic mammals, Erythrotherium parringtoni and Megazostrodon rudnerae. Bulletin of the British Museum (Natural History), Geology 24: 397–437. Google Scholar

    8.

    A.W. Crompton and F.A. Jenkins Jr. 1968. Molar occlusion in Late Triassic mammals. Biological Reviews 43: 427–458. Google Scholar

    9.

    R. Dadlez and J. Kopik 1963. Problem retyku w zachodniej Polsce na tle profilu w Książu Wielkopolskim. Kwartalnik Geologiczny 7: 131–158. Google Scholar

    10.

    P.M. Datta 2005. Earliest mammal with transversely expanded upper molar from the Late Triassic (Carnian) Tiki Formation, South Rewa Gondwana Basin, India. Journal of Vertebrate Paleontology 25: 200–207. Google Scholar

    11.

    P.M. Datta and D.P. Das 1996. Discovery of the oldest fossil mammal from India. India Minerals 50: 217–222. Google Scholar

    12.

    Z. Deczkowski 1997. Noryk-Retyk, Jura dolna. In : S. Marek and M. Pajchlowa (eds.), Epikontynentalny perm i mezozoik w Polsce. Prace Państwowego Instytutu Geologicznego 153: 174–235. Google Scholar

    13.

    J. Dzik , G. Niedźwiedzki , and T. Sulej 2008a. Zaskakujące uwieńczenie ery gadów ssakokształtnych. Ewolucja 3: 2–21. Google Scholar

    14.

    J. Dzik , T. Sulej , and G. Niedźwiedzki 2008b. A dicynodont−theropod association in the latest Triassic of Poland. Acta Paleontologica Polonica 53: 733–738. Google Scholar

    15.

    M. Franz 2008. Litho- und Leitflächenstratigraphie, Chronostratigraphie, Zyklo- und Sequenzstratigraphie des Keupers im östlichen Zentraleuropäischen Becken (Deutschland, Polen) und Dänischen Becken (Dänemark, Schweden). 198 pp. Dissertation zur Erlangung des akademischen Grades doctor rerum naturalium (Dr. rer. nat.) vorgelegt der Naturwissenschaftlichen Fakultät III der Martin-Luther-Universität, Halle-Wittenberg. Google Scholar

    16.

    M. Franz , G.H. Bachmann , and G. Beutler 2007a. Retyk sensu polonico versus Rhaet sensu germanico-new results. Schriftenreihe der Deutschen Gesellschaft für Geowissenschaften 53: 99–100. Google Scholar

    17.

    M. Franz , G.H. Bachmann , and G. Beutler 2007b. Sedimentology and Facies of the Polish Retyk and the German Arnstadt and Exter Formations (Norian, Rhaetian) in the eastern Central European Basin (CEB). Schriftenreihe der Deutschen Gesellschaft für Geowissenschaften 53: 101. Google Scholar

    18.

    R. Fuglewicz 1977. New species of megaspores from the Trias of Poland. Acta Palaeontologica Polonica 22: 405–431. Google Scholar

    19.

    R. Fuglewicz and P. Śnieżek 1980. Upper Triassic megaspores from Lipie Śląskie near Lubliniec. Przegląd Geologiczny 28: 459–461. Google Scholar

    20.

    G. Gierliński , G. Pieńkowski , and G. Niedźwiedzki 2004. Tetrapod track assemblage in the Hettangian of Sołtyków, Poland, and its paleoenvironmental background. Ichnos 11: 195–213. Google Scholar

    21.

    C.E. Gow 1986. A new skull of Megazostrodon (Mammalia: Triconodonta) from the Elliot Formation (Lower Jurassic) of southern Africa. Palaeontologia Africana 26: 13–23. Google Scholar

    22.

    G. Hahn , D. Sigogneau-Russell , and P. Godefroit 1991. New data on Brachyzostrodon (Mammalia; Upper Triassic). Geologica et Paleontologica 25: 237–249. Google Scholar

    23.

    J. Haisig , S. Kotlicki , S. Wilanowski , and W. Żurek 1983. Objaśnienia do szczegółowej mapy geologicznej Polski, Arkusz Lubliniec. 46 pp. Wydawnictwa Geologiczne, Warszawa. Google Scholar

    24.

    T.S. Kemp 2005. The Origin and Evolution of Mammals. 331 pp. Oxford University Press, Oxford. Google Scholar

    25.

    K.A. Kermack , F. Mussett , and H.W. Rigney 1973. The lower jaw of Morganucodon. Journal of the Linnean Society (Zoology) 53: 87–175. Google Scholar

    26.

    Z. Kielan-Jaworowska , R.L. Cifelli , and Z.-X. Luo 2004. Mammals from the Age of Dinosaurs: Origins, Evolution, and Structure. 630 pp. Columbia University Press, New York. Google Scholar

    27.

    H.W. Kozur and R.E. Weems 2010. The biostratigraphic importance of conchostracans in the continental Triassic of the northern hemisphere. In : S.G. Lucas (ed.), The Triassic Timescale. Geological Society of London Special Publications 334: 315–417. Google Scholar

    28.

    S.G. Lucas , A.B. Heckert , J.D. Harris , D. Seegis , and R. Wild 2001. Mammal-like tooth from the Upper Triassic of Germany. Journal of Vertebrate Paleontology 21: 397–399. Google Scholar

    29.

    Z.-X. Luo 1994. Sister-group relationships of mammals and transformations of diagnostic mammalian characters. In : N.C. Fraser and H.-D. Sues (eds.), In the Shadow of the Dinosaurs: Early Mesozoic Tetrapods , 98–128. Cambridge University Press, Cambridge. Google Scholar

    30.

    Z.-X. Luo 2007. Transformation and diversification in early mammalian evolution. Nature 450: 1011–1019. Google Scholar

    31.

    Z.-X. Luo 2011. Developmental patterns in Mesozoic evolution of mammalian ears. Annual Review of Ecology, Evolution, and Systematics 42: 355–380. Google Scholar

    32.

    Z.-X. Luo , A.W. Crompton , and A.-L. Sun 2001. A new mammal from the Early Jurassic and evolution of mammalian characteristics. Science 292: 1535–1540. Google Scholar

    33.

    J.R.E. Mills 1971. The dentition of Morganucodon. In : D.M. Kermack and K.A. Kermack (eds.), Early Mammals. Zoological Journal of the Linnean Society 50 (Supplement 1): 29–63. Google Scholar

    34.

    G. Niedźwiedzki , P. Gorzelak , and T. Sulej 2011. Bite traces on dicynodont bones and the early evolution of large terrestrial predators. Lethaia 44: 87–92. Google Scholar

    35.

    G. Niedźwiedzki , T. Sulej , and J. Dzik 2012. A large predatory archosaur from the Late Triassic of Poland. Acta Palaeontologica Polonica 57: 267–276. Google Scholar

    36.

    T. Orłowska-Zwolińska 1983. Palinostratygrafia epikontynentalnych osadów wyższego triasu w Polsce. Prace Instytutu Geologicznego 104: 1–88. Google Scholar

    37.

    G. Pieńkowski , G. Niedźwiedzki , and M. Waksmundzka 2012. Sedimentological, palynological, and geochemical studies of the terrestrial Triassic- Jurassic boundary in north-western Poland. Geological Magazine 149: 308–332. Google Scholar

    38.

    T.B. Rowe , T.E. Macrini , and Z.-X. Luo 2011. Fossil evidence of the origin of the mammalian brain. Science 332: 955–957. Google Scholar

    39.

    D. Seegis 2005. Tetrapoden. In : Deutsche Stratigraphische Kommission (ed.), Stratigraphie von Deutschland, Keuper-Band. Courier Forschungsinstitut Senckenberg 253: 50–51. Google Scholar

    40.

    C.A. Sidor and J.A. Hopson 1998. Ghost lineages and “mammalness”: assessing the temporal pattern of character acquisition in the Synapsida. Paleobiology 24: 254–273. Google Scholar

    41.

    D. Sigogneau-Russell 1983a. A new therian mammal from the Rhaetic locality of Saint-Nicolas-de-Port (France). Zoological Journal of the Linnean Society 78: 175–186. Google Scholar

    42.

    D. Sigogneau-Russell 1983b. Nouveaux taxons de Mammifères rhétiens. Acta Palaeontologica Polonica 28: 233–249. Google Scholar

    43.

    K. Staneczko 2007. Nowe dane paleobotaniczne na temat górnego triasu z Lipia Śląskiego koło Lublińca (południowa Polska). In : A. Frej (ed.), Geo-Sympozjum Młodych Badaczy Silesia 2007 , 155–168. Wydawnictwo Uniwersytetu Śląskiego, Katowice. Google Scholar

    44.

    M. Świło 2010a. Szczątki rekinów triasowych na Śląsku, ich użyteczność w stratygrafii i paleoekologii. 59 pp. Unpublished M.Sc. thesis, Wydział Nauk o Ziemi i Kształtowania Środowiska, Uniwersytet Wrocławski, Wrocław. Google Scholar

    45.

    M. Świło 2010b. Znaleziska szczątków rekinów ze stanowiska Lipie Śląskie. In : Z. Dubicka , P. Gorzelak , and Ł. Rakowicz (eds.), Materiały do II Konferencji „Młodzi w Paleontologii” , 40–41. Instytut Paleobiologii PAN, Warszawa. Google Scholar

    46.

    M. Świło 2010c. Znaleziska szczątków rekinów z Lipia Śląskiego. In : M. Zatoń , W. Krawczyński , M. Salamon , and A. Bodzioch (eds.), Materiały z XXI Konferencji Naukowej Sekcji Paleontologicznej PTG „Kopalne biocenozy w czasie i przestrzeni” , 84. Wydział Nauk o Ziemi, Uniwersytet Śląski, Żarki-Letnisko. Google Scholar

    47.

    M. Świło and J. Kowalski 2011. Mikroskamieniałości kręgowców z Lipia Śląskiego. In : A. Jarzynka , P. Olejniczak , and A. Jurochnik (eds.), Materiały do III Konferencji „Młodzi w Paleontologii” , 42. Instytut Botaniki PAN, Kraków. Google Scholar

    48.

    J. Szulc , M. Gradziński , A. Lewandowska , and C. Heunisch 2006. The Upper Triassic crenogenic limestones in Upper Silesia (southern Poland) and their paleoenvironmental context. In : A.M. Alonso-Zarza and L.H. Tanner (eds.), Paleoenvironmental Record and Applications of Calcretes and Palustrine Carbonates. Geological Society of America Special Paper 416: 133–151. Google Scholar

    49.

    T.N. Taylor , E.L. Taylor , and M. Krings 2009. Paleobotany: The Biology and Evolution of Fossil Plants. 1230 pp. Academic Press, Amsterdam. Google Scholar
    Copyright ©2014 M. Świło et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
    Marlena Świło, Grzegorz Niedźwiedzki, and Tomasz Sulej "Mammal-Like Tooth from the Upper Triassic of Poland," Acta Palaeontologica Polonica 59(4), 815-820, (13 December 2013). https://doi.org/10.4202/app.00016.2013
    Received: 7 August 2013; Accepted: 2 December 2013; Published: 13 December 2013
    Back to Top