(Lower Paleocene) of Faxe Quarry, Denmark
Bulletin 51 New Mexico Museum of Natural History & Science A Division of the DEPARTMENT OF CULTURAL AFFAIRS
Crocodyle tracks and traces
edited by
Jesper Milàn, Spencer G. Lucas, Martin G. Lockley and Justin A. Spielmann Albuquerque, 2010
Milàn, J., Lucas, S.G., Lockley, M.G. and Spielmann, J.A., eds., 2010, Crocodyle tracks and traces. New Mexico Museum of Natural History and Science, Bulletin 51.
215
COPROLITES FROM THE DANIAN LIMESTONE (LOWER PALEOCENE) OF FAXE QUARRY, DENMARK JESPER MILÀN Geomuseum Faxe/Østsjællands Museum, Østervej 2, DK-4640 Faxe, Denmark and Department of Geography and Geology, University of Copenhagen, Øster voldgade 10, DK-1350 Copenhagen K. Denmark; e-mail: [email protected]
Abstract—A collection of coprolites found in the Danian (Lower Paleocene) limestone of Faxe Quarry, Denmark, is described and attributed to the respective producers. Small, drop-like specimens with weak signs of spiral coiling are attributed to fish. Larger, heteropolar, spirally-coiled specimens are attributed to sharks, and large, cylindrical coprolites with longitudinal striations on the surface are identified as crocodile coprolites. Fish and sharks are known from abundant finds of otoliths and teeth in Faxe Quarry, and crocodiles are known from finds of single bones and teeth.
INTRODUCTION Faxe Limestone Quarry, situated in the southeastern part of Zealand, Denmark (Fig. 1), is world famous for its Danian, well-preserved deep-water coral mounds and highly diverse invertebrate fauna (Bernecker and Weidlich, 1990, 2005; Willumsen, 1995; Surlyk and Håkansson, 1999; Graversen, 2001). Furthermore, the Faxe Quarry, together with the nearby sea-cliff, Stevns Klint, is the type locality for the Danian Stage (Desor, 1847). Faxe is situated in the Danish-Polish trough, which is bounded to the south by the Ringkøbing-Fyn structural high and to the north by the Fennoscandian shield (Fig. 1) (Surlyk and Håkansson, 1999). In addition to the extensive invertebrate fauna (Graversen, 2001), vertebrates are represented by 13 species of marine fish (Schwarzhans, 2003), 15 species of sharks (Jan Schultz Adolfssen, pers. comm, 2009) and crocodiles (Bonde et al., 2008). Further evidence of vertebrates is found in the form of polished quartz pebbles interpreted as gastroliths (Noe-Nygaard, 1975). Here, I describe a number of coprolites from the collections of Geomusem Faxe/Østsjællands Museum (10006-19, 10006- 58 and 10006-59) and of the private collectors Alice and Henning Rasmussen, Faxe, and assign the
coprolites to their respective producers. COPROLITES The coprolites were all collected in Faxe Quarry around 1998 when an extremely fossil-rich layer was temporarily exposed. A total of 49 coprolites were examined, but many were too fragmentary or eroded to be identified as more than just coprolites. However, 11 specimens ranging from 11 to 26 mm long are sufficiently well-preserved to be identified. Based on their external morphology, the coprolites are divided into three general morphotypes: One type consists of small, 11 to 14 mm long, spherical to drop-like coprolites, with small, pointed ends. The surface is smooth, and the coprolite appears to be composed of numerous thin layers. There are weak signs of spiral coiling at the pointed ends of the coprolites (Fig. 2). A second group consists of heteropolar, spiral coprolites with an irregular surface. They are composed of several layers “wrapped” irregularly around each other, giving the coprolite the superficial appearance of a pine-cone. They measure 14 to 23 mm long and have a maximum diameter of 11 mm (Fig. 3). A broken specimen shows the internal coiling
FIGURE 1. Faxe Limestone Quarry is located in the southeastern part of Denmark. Location map modified from Schnetler et al. (2001).
216
FIGURE 2. A-C, small drop-like coprolites, probably from fish. A, Geomuseum Faxe no. 10006-58. Scale bar = 1 cm.
DISCUSSION
FIGURE 3. Heteropolar, spirally-coiled coprolites from sharks. A-B, Complete specimens showing clear coiling of the surface. A, Geomuseum Faxe no. 10006-59. C, Specimens that are broken in half. D, The broken surface of C, shows the internal coiling of the specimen. All specimens shown to same size. Scale bar = 1 cm.
to consist of six mm-thin layers tightly wrapped around each other (Fig. 3D). The last type is large coprolites, cylindrical in cross section, and with diameters of up to 24 mm (Fig. 4). The surface of the coprolites is smooth, with occasional longitudinal striations (Fig. 4D). All the examined specimens seem to be broken fragments of longer specimens, and the unbroken ends of the coprolites are rounded, as they have been terminated by constriction. Some of the broken surfaces show the coprolites to be composed of concavo-convex units (Fig. 4A). One specimen has preserved the partly dissolved remains of an indeterminate fish vertebra (Fig. 4E-F).
All the coprolites collected in Faxe Quarry are in excess of 5 mm in total length. This excludes most invertebrates as producers, as their fecal pellets normally are less than 5 mm long (Häntzschel et al., 1968). The vertebrate fauna from Faxe Quarry consists of 13 species of fish (Schwarzhans, 2003) and 15 species of sharks. Size-wise, the sharks ranged from 0.5 to 5 meter long (Jan Schultz Adolfssen, pers. comm. 2009). Crocodilian body remains from Faxe are known from two finds of bones, a basioccipital and a cervical vertebra, both stored in the collection of the Geological Museum of the Natural History Museum of Denmark (Bonde et al., 2008), and several loose teeth from the collection of Geomuseum Faxe/Østsjællands Museum and private collectors. A complete skull and a partial upper jaw were described from the similar-aged Limhamn Quarry in Malmø, southern Sweden, as Thoracosaurus scanicus (Troedsson, 1923, 1924). Spiral-shaped coprolites are generally attributed to fish having a spiral valve (Hunt et al., 1994; Sumner, 1994; Northwood, 2005), and the heteropolar spiral coprolites are attributed to sharks, due to their more complex valves (McAllister, 1985). The large coprolites are all elongated and cylindrical to slightly flattened in cross-section. This is a shape commonly found in crocodylian coprolites of all ages, fossil and recent (Young, 1964; Sawyer, 1981; Thulborn, 1991; Souto, this volume; Milàn & Hedegaard, this volume), and it is a general shape for fossil (Chin, 2002) and modern animals having a diet similar to that of crocodilians (Chame, 2003; Stuart and Stuart, 1998). The presence of a recognizable fish vertebra in one of the specimens (Fig. 4E-F), suggest that it originated from another animal, as the digestion system of crocodiles tend to decalcify and dissolve bone tissue before it is excreted (Fischer, 1981). The concave endings of some of the coprolite specimens (Fig. 4A) are consistent with that of Cretaceous crocodile coprolites from Brazil (Souto, this volume), and what is observed in recent crocodile faeces (Milàn and Hedegaard, this volume). Coprolites with longitudinal striations on their surface have been described from Paleocene coprolites attributed to crocodiles and in recent crocodile fecal pellets (Young, 1964), as well as in Cretaceous specimens (Rodríguez-de la Rosa et al., 1998). Northwood (2005) discusses longitudinally striated coprolites and attributes them to archosauromorphs. Crocodiles are the only archosaurs known from the fossil record of the Danian limestone of Faxe Quarry, and are thus the most likely producers of the large coprolites. CONCLUSION Three different types of coprolites are described from the Danian limestone in Faxe Quarry. Small drop-like coprolites are attributed to indeterminate fish, and larger, spirally-coiled specimens are identified as shark coprolites. Large cylindrical coprolites, with longitudinal striations on the surface and a content of fish remains, are identified as crocodile coprolites. This is the first record of crocodilian coprolites from Denmark.
217
FIGURE 4. Large cylindrical crocodile coprolites. A-C, large specimens, that are all fragments of longer coprolites. The unbroken ends are rounded. B, Geomuseum Faxe no. 10006-19. D, Coprolite showing longitudinal striations preserved in parts of the surface, indicated by arrows. E, Coprolite containing a partially dissolved vertebra from a fish. This coprolite might not have been produced by a crocodile. F, Close-up of the fish vertebra in E. A-E are reproduced to the same scale. Scale bar = 1 cm.
ACKNOWLEDGMENTS The research of JM is supported by the Danish Natural Science Research Council. I am grateful to Alice and Henning Rasmussen for
making their coprolites available for scientific investigations. The critical reviews by Richard G. Bromley and Paulo Souto helped to improve the manuscript significantly.
REFERENCES Bernecker, M. and Weidlich, O., 1990, The Danian (Paleocene) Coral Limestone of Fakse, Denmark: A model for ancient aphotic, azooxanthellate coral mounds: Facies, v. 22, p. 103–138. Bernecker, M. and Weidlich, O., 2005, Azooxanthellate corals in the Late Maastrichtian - Early Paleocene of the Danish basin: Bryozoan and coral mounds in a boreal shelf setting; in Freiwald, A. and Roberts, J.M., eds., Cold-water corals and ecosystems: Springer Verlag, p. 3–25. Bonde, N., Andersen, S., Hald, N. and Jakobsen, S.L., 2008, Danekræ – Danmarks bedste fossiler: Gyldendal, Denmark, 224 pp. Chame, M., 2003, Terrestrial mammal feces: A morphometric summary and description: Memoirs of the Institute Oswaldo Cruz, v. 98, p. 71–94. Chin, K., 2002, Analyses of coprolites produced by carnivorous vertebrates: Paleontological Society Papers, v. 8, p. 43–50. Desor, E., 1847, Sur le terrain danien, nouvel étage de la craie: Bulletin de la Société Géologique de la France, Sér. 2, v. 4, p. 179–182. Fischer, D.F., 1981, Crocodilian scatology, microvertebrate concentrations, and enamel-less teeth: Paleobiology, v. 7, p. 262–275. Graversen, P., 2001, Den geologiske udforskning af Fakse Kalkbrud fra midten af 1700-tallet til nu: Geologisk Tidsskrift, v. 2, p. 1–40. Häntzschel, W., El-Baz, F. and Amstutz, G.C., 1968, Coprolites: An annotated bibliography: Geological Society of America, Memoir 108, p. 1– 132. Hunt, A.P., Chin, K. and Lockley, M.G., 1994, The paleobiology of verte-
brate coprolites; in Donovan, S., ed., The Palaeobiology of Trace Fossils, John Wiley and Sons, London, p. 221–240. McAllister, J.A., 1985, Reevaluation of the formation of spiral coprolites: University of Kansas, Paleontological Contributions, v. 144, p. 1–12. Milàn, J. and Hedegaard, R., 2010, Interspecific variations in tracks and trackways of extant crocodiles: New Mexico Museum of Natural History and Science, Bulletin, this volume. Noe-Nygaard, A., 1975, Erratics from the Danish Maastrichtian and Danian Limestones: Bulletin of the Geological Society of Denmark, v. 24, p. 75–81. Northwood, C., 2005, Early Triassic coprolites from Australia and their palaeobiological significance: Palaeontology, v. 48, p. 49–68. Rodríguez-de la Rosa, R.A., Cevallos-Ferriz, S.R.S. and Silva-Pineda, A., 1998, Paleobiological implications of Campanian coprolites: Palaeogeography, Palaeoclimatology, Palaeoecology, v.142, p. 231– 254. Sawyer, G. T., 1981, A study of crocodilian coprolites from Wannagan Creek Quarry Minnesota: Scientific Publications of The Science Museum of Minnesota, v. 5, p. 1–29. Schnetler, K.I., Lozouet, P. and Pacaud, J.-M., 2001, Revision of the gastropod family Scissurellidae from the Middle Danian (Paleocene) of Denmark: Bulletin of the Geological Society of Denmark, v. 48, p. 79– 90.
218 Schwarzhans, W., 2003, Fish otoliths from the Paleocene of Denmark: Geological Survey of Denmark and Greenland Bulletin, v. 2, p. 1 – 94. Souto, P.R.F., 2010, The crocodylomorph coprolites from Baru Basin, Upper Cretaceous, Brazil: New Mexico Museum of Natural History and Science, Bulletin, this volume. Stuart, C. and Stuart, T., 1998, A field guide to the tracks and signs of southern and East African wildlife: Southern Books Publishers, Cape Town, 310 p. Sumner, D., 1994, Coprolites from the Viséan of East Kirkton, West Lothian, Scotland: Transactions of the Royal Society of Edinbourgh, Earth Sciences, v. 84, p. 413–416. Surlyk, F. and Håkansson, E., 1999, Maastrichtian and Danian strata in the southeastern part of the Danish Basin; in Pedersen, G. K and Clemmesen,
L., eds., Field Trip Guidebook, 19th Regional European Meeting of Sedimentology, p. 29–58. Thulborn, R.A., 1991, Morphology, preservation and palaeobiological significance of dinosaur coprolites: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 83, p. 341–366. Troedsson, G.T., 1923, Om krokodilfyndan i Skånes yngsta Krita: GFF, v. 45, p. 549 – 567. Troedsson, G.T., 1924, On crocodilian remains from the Danian of Sweden: Lunds Universitets Årsskrift, v. 20, p. 1–75. Willumsen, M., 1995, Early lithification in Danian azooxanthellate scleractinian lithoherm, Faxe Quarry, Denmark: Beiträge zur Paläontologie, v. 20, p. 123–131. Young, C.C., 1964, New fossil crocodiles from China: Vertebrate Palasiatica, v. 8, p.190–208.
Crocodyle tracks and traces
edited by
Jesper Milàn, Spencer G. Lucas, Martin G. Lockley and Justin A. Spielmann Albuquerque, 2010
Milàn, J., Lucas, S.G., Lockley, M.G. and Spielmann, J.A., eds., 2010, Crocodyle tracks and traces. New Mexico Museum of Natural History and Science, Bulletin 51.
215
COPROLITES FROM THE DANIAN LIMESTONE (LOWER PALEOCENE) OF FAXE QUARRY, DENMARK JESPER MILÀN Geomuseum Faxe/Østsjællands Museum, Østervej 2, DK-4640 Faxe, Denmark and Department of Geography and Geology, University of Copenhagen, Øster voldgade 10, DK-1350 Copenhagen K. Denmark; e-mail: [email protected]
Abstract—A collection of coprolites found in the Danian (Lower Paleocene) limestone of Faxe Quarry, Denmark, is described and attributed to the respective producers. Small, drop-like specimens with weak signs of spiral coiling are attributed to fish. Larger, heteropolar, spirally-coiled specimens are attributed to sharks, and large, cylindrical coprolites with longitudinal striations on the surface are identified as crocodile coprolites. Fish and sharks are known from abundant finds of otoliths and teeth in Faxe Quarry, and crocodiles are known from finds of single bones and teeth.
INTRODUCTION Faxe Limestone Quarry, situated in the southeastern part of Zealand, Denmark (Fig. 1), is world famous for its Danian, well-preserved deep-water coral mounds and highly diverse invertebrate fauna (Bernecker and Weidlich, 1990, 2005; Willumsen, 1995; Surlyk and Håkansson, 1999; Graversen, 2001). Furthermore, the Faxe Quarry, together with the nearby sea-cliff, Stevns Klint, is the type locality for the Danian Stage (Desor, 1847). Faxe is situated in the Danish-Polish trough, which is bounded to the south by the Ringkøbing-Fyn structural high and to the north by the Fennoscandian shield (Fig. 1) (Surlyk and Håkansson, 1999). In addition to the extensive invertebrate fauna (Graversen, 2001), vertebrates are represented by 13 species of marine fish (Schwarzhans, 2003), 15 species of sharks (Jan Schultz Adolfssen, pers. comm, 2009) and crocodiles (Bonde et al., 2008). Further evidence of vertebrates is found in the form of polished quartz pebbles interpreted as gastroliths (Noe-Nygaard, 1975). Here, I describe a number of coprolites from the collections of Geomusem Faxe/Østsjællands Museum (10006-19, 10006- 58 and 10006-59) and of the private collectors Alice and Henning Rasmussen, Faxe, and assign the
coprolites to their respective producers. COPROLITES The coprolites were all collected in Faxe Quarry around 1998 when an extremely fossil-rich layer was temporarily exposed. A total of 49 coprolites were examined, but many were too fragmentary or eroded to be identified as more than just coprolites. However, 11 specimens ranging from 11 to 26 mm long are sufficiently well-preserved to be identified. Based on their external morphology, the coprolites are divided into three general morphotypes: One type consists of small, 11 to 14 mm long, spherical to drop-like coprolites, with small, pointed ends. The surface is smooth, and the coprolite appears to be composed of numerous thin layers. There are weak signs of spiral coiling at the pointed ends of the coprolites (Fig. 2). A second group consists of heteropolar, spiral coprolites with an irregular surface. They are composed of several layers “wrapped” irregularly around each other, giving the coprolite the superficial appearance of a pine-cone. They measure 14 to 23 mm long and have a maximum diameter of 11 mm (Fig. 3). A broken specimen shows the internal coiling
FIGURE 1. Faxe Limestone Quarry is located in the southeastern part of Denmark. Location map modified from Schnetler et al. (2001).
216
FIGURE 2. A-C, small drop-like coprolites, probably from fish. A, Geomuseum Faxe no. 10006-58. Scale bar = 1 cm.
DISCUSSION
FIGURE 3. Heteropolar, spirally-coiled coprolites from sharks. A-B, Complete specimens showing clear coiling of the surface. A, Geomuseum Faxe no. 10006-59. C, Specimens that are broken in half. D, The broken surface of C, shows the internal coiling of the specimen. All specimens shown to same size. Scale bar = 1 cm.
to consist of six mm-thin layers tightly wrapped around each other (Fig. 3D). The last type is large coprolites, cylindrical in cross section, and with diameters of up to 24 mm (Fig. 4). The surface of the coprolites is smooth, with occasional longitudinal striations (Fig. 4D). All the examined specimens seem to be broken fragments of longer specimens, and the unbroken ends of the coprolites are rounded, as they have been terminated by constriction. Some of the broken surfaces show the coprolites to be composed of concavo-convex units (Fig. 4A). One specimen has preserved the partly dissolved remains of an indeterminate fish vertebra (Fig. 4E-F).
All the coprolites collected in Faxe Quarry are in excess of 5 mm in total length. This excludes most invertebrates as producers, as their fecal pellets normally are less than 5 mm long (Häntzschel et al., 1968). The vertebrate fauna from Faxe Quarry consists of 13 species of fish (Schwarzhans, 2003) and 15 species of sharks. Size-wise, the sharks ranged from 0.5 to 5 meter long (Jan Schultz Adolfssen, pers. comm. 2009). Crocodilian body remains from Faxe are known from two finds of bones, a basioccipital and a cervical vertebra, both stored in the collection of the Geological Museum of the Natural History Museum of Denmark (Bonde et al., 2008), and several loose teeth from the collection of Geomuseum Faxe/Østsjællands Museum and private collectors. A complete skull and a partial upper jaw were described from the similar-aged Limhamn Quarry in Malmø, southern Sweden, as Thoracosaurus scanicus (Troedsson, 1923, 1924). Spiral-shaped coprolites are generally attributed to fish having a spiral valve (Hunt et al., 1994; Sumner, 1994; Northwood, 2005), and the heteropolar spiral coprolites are attributed to sharks, due to their more complex valves (McAllister, 1985). The large coprolites are all elongated and cylindrical to slightly flattened in cross-section. This is a shape commonly found in crocodylian coprolites of all ages, fossil and recent (Young, 1964; Sawyer, 1981; Thulborn, 1991; Souto, this volume; Milàn & Hedegaard, this volume), and it is a general shape for fossil (Chin, 2002) and modern animals having a diet similar to that of crocodilians (Chame, 2003; Stuart and Stuart, 1998). The presence of a recognizable fish vertebra in one of the specimens (Fig. 4E-F), suggest that it originated from another animal, as the digestion system of crocodiles tend to decalcify and dissolve bone tissue before it is excreted (Fischer, 1981). The concave endings of some of the coprolite specimens (Fig. 4A) are consistent with that of Cretaceous crocodile coprolites from Brazil (Souto, this volume), and what is observed in recent crocodile faeces (Milàn and Hedegaard, this volume). Coprolites with longitudinal striations on their surface have been described from Paleocene coprolites attributed to crocodiles and in recent crocodile fecal pellets (Young, 1964), as well as in Cretaceous specimens (Rodríguez-de la Rosa et al., 1998). Northwood (2005) discusses longitudinally striated coprolites and attributes them to archosauromorphs. Crocodiles are the only archosaurs known from the fossil record of the Danian limestone of Faxe Quarry, and are thus the most likely producers of the large coprolites. CONCLUSION Three different types of coprolites are described from the Danian limestone in Faxe Quarry. Small drop-like coprolites are attributed to indeterminate fish, and larger, spirally-coiled specimens are identified as shark coprolites. Large cylindrical coprolites, with longitudinal striations on the surface and a content of fish remains, are identified as crocodile coprolites. This is the first record of crocodilian coprolites from Denmark.
217
FIGURE 4. Large cylindrical crocodile coprolites. A-C, large specimens, that are all fragments of longer coprolites. The unbroken ends are rounded. B, Geomuseum Faxe no. 10006-19. D, Coprolite showing longitudinal striations preserved in parts of the surface, indicated by arrows. E, Coprolite containing a partially dissolved vertebra from a fish. This coprolite might not have been produced by a crocodile. F, Close-up of the fish vertebra in E. A-E are reproduced to the same scale. Scale bar = 1 cm.
ACKNOWLEDGMENTS The research of JM is supported by the Danish Natural Science Research Council. I am grateful to Alice and Henning Rasmussen for
making their coprolites available for scientific investigations. The critical reviews by Richard G. Bromley and Paulo Souto helped to improve the manuscript significantly.
REFERENCES Bernecker, M. and Weidlich, O., 1990, The Danian (Paleocene) Coral Limestone of Fakse, Denmark: A model for ancient aphotic, azooxanthellate coral mounds: Facies, v. 22, p. 103–138. Bernecker, M. and Weidlich, O., 2005, Azooxanthellate corals in the Late Maastrichtian - Early Paleocene of the Danish basin: Bryozoan and coral mounds in a boreal shelf setting; in Freiwald, A. and Roberts, J.M., eds., Cold-water corals and ecosystems: Springer Verlag, p. 3–25. Bonde, N., Andersen, S., Hald, N. and Jakobsen, S.L., 2008, Danekræ – Danmarks bedste fossiler: Gyldendal, Denmark, 224 pp. Chame, M., 2003, Terrestrial mammal feces: A morphometric summary and description: Memoirs of the Institute Oswaldo Cruz, v. 98, p. 71–94. Chin, K., 2002, Analyses of coprolites produced by carnivorous vertebrates: Paleontological Society Papers, v. 8, p. 43–50. Desor, E., 1847, Sur le terrain danien, nouvel étage de la craie: Bulletin de la Société Géologique de la France, Sér. 2, v. 4, p. 179–182. Fischer, D.F., 1981, Crocodilian scatology, microvertebrate concentrations, and enamel-less teeth: Paleobiology, v. 7, p. 262–275. Graversen, P., 2001, Den geologiske udforskning af Fakse Kalkbrud fra midten af 1700-tallet til nu: Geologisk Tidsskrift, v. 2, p. 1–40. Häntzschel, W., El-Baz, F. and Amstutz, G.C., 1968, Coprolites: An annotated bibliography: Geological Society of America, Memoir 108, p. 1– 132. Hunt, A.P., Chin, K. and Lockley, M.G., 1994, The paleobiology of verte-
brate coprolites; in Donovan, S., ed., The Palaeobiology of Trace Fossils, John Wiley and Sons, London, p. 221–240. McAllister, J.A., 1985, Reevaluation of the formation of spiral coprolites: University of Kansas, Paleontological Contributions, v. 144, p. 1–12. Milàn, J. and Hedegaard, R., 2010, Interspecific variations in tracks and trackways of extant crocodiles: New Mexico Museum of Natural History and Science, Bulletin, this volume. Noe-Nygaard, A., 1975, Erratics from the Danish Maastrichtian and Danian Limestones: Bulletin of the Geological Society of Denmark, v. 24, p. 75–81. Northwood, C., 2005, Early Triassic coprolites from Australia and their palaeobiological significance: Palaeontology, v. 48, p. 49–68. Rodríguez-de la Rosa, R.A., Cevallos-Ferriz, S.R.S. and Silva-Pineda, A., 1998, Paleobiological implications of Campanian coprolites: Palaeogeography, Palaeoclimatology, Palaeoecology, v.142, p. 231– 254. Sawyer, G. T., 1981, A study of crocodilian coprolites from Wannagan Creek Quarry Minnesota: Scientific Publications of The Science Museum of Minnesota, v. 5, p. 1–29. Schnetler, K.I., Lozouet, P. and Pacaud, J.-M., 2001, Revision of the gastropod family Scissurellidae from the Middle Danian (Paleocene) of Denmark: Bulletin of the Geological Society of Denmark, v. 48, p. 79– 90.
218 Schwarzhans, W., 2003, Fish otoliths from the Paleocene of Denmark: Geological Survey of Denmark and Greenland Bulletin, v. 2, p. 1 – 94. Souto, P.R.F., 2010, The crocodylomorph coprolites from Baru Basin, Upper Cretaceous, Brazil: New Mexico Museum of Natural History and Science, Bulletin, this volume. Stuart, C. and Stuart, T., 1998, A field guide to the tracks and signs of southern and East African wildlife: Southern Books Publishers, Cape Town, 310 p. Sumner, D., 1994, Coprolites from the Viséan of East Kirkton, West Lothian, Scotland: Transactions of the Royal Society of Edinbourgh, Earth Sciences, v. 84, p. 413–416. Surlyk, F. and Håkansson, E., 1999, Maastrichtian and Danian strata in the southeastern part of the Danish Basin; in Pedersen, G. K and Clemmesen,
L., eds., Field Trip Guidebook, 19th Regional European Meeting of Sedimentology, p. 29–58. Thulborn, R.A., 1991, Morphology, preservation and palaeobiological significance of dinosaur coprolites: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 83, p. 341–366. Troedsson, G.T., 1923, Om krokodilfyndan i Skånes yngsta Krita: GFF, v. 45, p. 549 – 567. Troedsson, G.T., 1924, On crocodilian remains from the Danian of Sweden: Lunds Universitets Årsskrift, v. 20, p. 1–75. Willumsen, M., 1995, Early lithification in Danian azooxanthellate scleractinian lithoherm, Faxe Quarry, Denmark: Beiträge zur Paläontologie, v. 20, p. 123–131. Young, C.C., 1964, New fossil crocodiles from China: Vertebrate Palasiatica, v. 8, p.190–208.
