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Eocene sharks in The Limfjord area

The Chondrichthyes assemblages from the Søvind Marl Formation is compared to the Fur Formation and the Ølst Formation, from the Isle of Mors in Denmark. The fauna witnesses a dramatic shift in the Chondrichthyes fauna during around 20 ma. years, with a significant change of the environment in a very small area in the Early Eocene to Late Eocene.

HENRIK MADSEN

A new found Chondrichthyes assemblages from the Late Eocene Søvind Marl Formation (Late Priabonian) on the Isle of Mors in Denmark yielded teeth of 33 different genera/species from bulk sampling. The fauna is dominated by deepwater genera like Centrophorus, Isistius, Echinorhinus, Lamniform, Pristiophorus and Hexanchiformes. All the shark teeth are reported for the first time from the Late Priabonian, Søvind Marl Formation in Denmark.

The faunas suggests deposition in a reltive deep-water environment in subtropical waters on the middle or outer continental shelf at water depth from 100 to 400 m (Schmitz et al. 1996).

Keywords: Denmark, Søvind Marl Formation, Fur Formation, Ølst Formation, Lower Eocene, Chondrichthyes, fossil teeth.

Henrik Madsen [henrik.madsen@museummors.dk], Fossil- og Molermuseet, Museum Mors,

Skarrehagevej 8, 7900 Nykøbing Mors, Denmark.

The aim of this paper is to make a list on the chondrichthyes fossil teeth from the Søvind Marl Formation (Heilmann-Clausen 1982), on the Isle of Mors, Denmark, and compare the assemblage with the Fur Formation which is underlying the Søvind Marl Formation. Furthermore the special unformal Sundbylayer, rich in elasmobranch fossil teeth deposited between the Stolleklint Clay and the Fur Formation are used to compare the fauna before the Fur Formation and Søvind Marl Formation. This fauna, although well known by palaeontologists in Denmark, has never been described in the scientific literature. Moreover, the composition of the fauna gives information on the climate and depositional environment. The screen-washed bulk material from the layers, bonebed G1 and bonebed G2 of the Søvind Marl Formation, and the provenance of this material is therefore precisely known, dating from the Late Priabonian, Thalassiphora reticulata dinoflagellate Zone (Heilmann-Clausen 1988).The locality at Grønbjerg Klint and the material are new to science.

In the Fur Formation the assemblage of the elasmobranch only consist of 7 different genera/species. The assemblage of the chondrichthyes in the Sundbylayer consist of 20 different genera. The assemblage of the chondrichthyes in the Søvind Marl Formation,
consist of 33 different genera/species
.



Fig. 1. The places were the different
types of clay in this articel are found.
1: Sundby Klint, 2: Hanklit, 3: Salgerhøj Klint, 4: Grønbjerg Klint. 5: Knudeklint. 6: Stolleklint.

Geological setting

In a distance of 7 km from Sundby Klint to Grønbjerg Klint on the Isle of Mors, it is possible to find shark teeth in these tree Geological Formations: Ølst Formation, Fur Formation, Søvind Marl Formation. The time span is around 20 ma. Age 55,8 – 34,0 ma.

Here the shark assemblage is compared in a small area in the North Sea basin were the fossils were deposited, at a time when the area went through some huge changes in climate and environment. The Paleocene-Eocene Thermal Maximum Kennett & Stott (1991) began approximately 55,8 million years before present (Röhl et al. 2007) and lasted about 170,000 years. The PETM involved more than 5 C° of warming. The Eocene Thermal Maximum 2 was another period of global warming that occurred approximately 53.7 million years before present and represents the second largest of the major Eocene hyperthermals. In the Late Priabonian, the Earth’s climate entered a phase with decreasing temperatures, culminating at the Eocene–Oligocene transition (EOT). The Late Priabonian temperature had a 10 °C temperature fall, starting at 36.1 Ma and culminating near the EOT at 33.9 Ma. (Śliwińska K.K. 2019).


Fig. 2. Paleomaps modified from Bonde 1972 and Ziegler 1990.
1: Ølst Formation, 2: Fur Formation, 3: Søvind Marl Formation.

Ølst-Formation

The shark teeth from the Ølst-Formation are rarely found in the shale, over the volcanic ash layer -33, but the far most specimens and species is from the unofficial layer Sundby-layer, that overlies the Stolleklint Clay - Age 56,0 -55,8 ma.

Fur-Formation

The shark teeth from the Fur-Formation are rarely found in the 60 meter thick diatomite called Mo-Clay. Single shark teeth are found throughout the whole formation. The striated cement stone from the level with volcanic ash layer -24 to -28, which is the lower part of the Fur Formation, have yield most shark teeth. Age 55,8-54.0 ma.

Søvind Marl Formation

The shark teeth from the Søvind Marl Formation at Grønbjerg Klint are from the Late Priabonian overlies the Fur Formation that is Early Ypresian, and on this locality the author has observed arround 6 meters of unknown layers, that expands the Fur Formation. On top of these new layers is visible. The layers are not identical with Søvind Marl, but are equivalent in age to the layers from this Formation. - Age 34,0 ma.


Fig. 3. Modified from Stokke et. al. 2020.

Grønbjerg Klint is a coast cliff in Northern Jutland on the Isle of Mors, near the small village of Flade (Fig. 1). During the Eocene, the Danish area was covered by the North Sea and clays and marls were deposited. When the Søvind Marl Formation was deposited, in a period where the English Channel was open, and the warm Atlantic Ocean made the sea level higher than when the Stolleklint Clay and Mo-clay sediments were deposited. The fine-grained clays of the Søvind Marl Formation and the Moclay are exposed in outcrops on the N-coast of Mors. Small outcrops of Stolleklint Clay and Holmehus Clay with the Paleocene-Eocene boundery have been observed on the beach at Sundby Klint. The Søvind Marl Formation, is only known from this locality in the Limfjord area.

Stratigraphy

The Søvind Marl Formation has been logged by Heilmann-Clausen et al. (1985) It is restricted to this locality in the western Limfjord area.

At Grønbjerg Klint the Søvind Marl Formation layers is different than the layers in the rest of Denmark. The stratigraphy of the Søvind Marl Formation is illustrated by Heilmann-Clausen et al. 1985. At Grønbjerg Klint 4 meter is more or less exposed in a landslide west of the mo-clay cliff. It is also overlaying the moclay with 36 cm red-brown clay on top of the Grønbjerg Klint. Søvind Marl Formation at Grønbjerg Klint, is red-brown, green, gray and grey-green, glauconitic fine-grained waxy clay, with light yellow and grey burrows preserved as small calcareous concretions.


Fig. 4. The landslide area with the Søvind Marl Formation at Grønbjerg Klint.


Fig. 5. The aurthor Henrik Madsen with the G2 layer at Grønbjerg Klint.

In the two measured profiles in the big landslide profile A, is 1,5 meter high and 15 meter in length. Furthermore a excavated ditch presents 2,4 meter green and brown clay below the glauconitic layer (G 1). In a slide a few meters behind and above this profile, the glauconitic layer G 2 is visible. Profile B is a 3,3 meter high and 10 meter wide profile, with the two glauconitic rich layers present (G 1 and G 2). At Grønbjerg Klint the Søvind Marl Formation is overlain by up to two meters glacial sand and pebbels.


Fig. 6. Drawing of the layers at Grønbjerg. In total, the thickness of the clay is over 484 cm.

Nanoplankton sample

The nanoplankton sample contains these dinoflagellates cysts:
Phthanoperidinium comatum,
Homotryblium floripes,
Areosphaeridium dictyoplokus,
Deflandrea phosphoritica,
Hystrichokolpoma cinctum,
Thalassiphora pelagica,
Wetzeliella sp.,

These specimens are all characteristic for the Areosphaeridium arcuatum
and Thalassiphora reticulata Zone (Heilmann-Clausen 1988).
This zone is in the upper part of the Søvind Marl Formation

The NP sample also contains these dinoflagellates cysts:
Eatonicysta ursulae,
Deflandrea oebisfeldensis,
Cordosphaeridium cantharellus,
Glaphyrocysta semitecta,
Enneadocysta arcuata.
Areoligera cf. senonensis.
The sampling work was done by Karen Dybkjær at The Geological Survey of Denmark and Greenland (GEUS).


Coccolites sample
The coccolite samples from the clay at Grønbjerg klint, contained the index coccolite Isthmolithus recurvus, that is unik for the Upper Søvind Marl Formation - NP 19-20.
The sampling work was done by Claus Heilmann Clausen.

Material and methods

The present paper is based on one collection. The examined part of the collection consists of a total of more than 6000 teeth. The majority of the teeth are from Lamniformes. Of the total number of teeth, ?% are identified to genus or species, ?% are identified only to family or order, and the remaining ?% of the teeth are so damaged that identification was not attempted. The precise stratigraphic origin of these teeth is from layer bed G1 and bed G2. (GPS coordinates: 56°54'05.6"N 8°47'55.2"E. in October 2020, but will in time slide towards the Limfjord). The bulk material was collected in 2020 and a total of approximately 1100 kg of clay has been processed. 850 kg from bed G1 and 250 kg from bed G2. The clay was dried, dissolved in water three times and screen washed through two different mesh sizes, where the coarse sieve has 2.0 mm meshes, and the smallest one has 0.5 mm. The 250 kg from G2 was reduced to 2,0 kg. The reduced material contain a lot of glauconite, some pyrite, grains of sand and borrows of chalk. The residues were searched for sharkteeth by HM using a binocular microscope (Euromex). About ?? % of the teeth are identified to genus or species. All illustrated fossils are housed in the Fossil- and MoclayMuseum, under the catalogue numbers, Specify xxxx. Teeth larger than 5 mm have been photographed with a Nikon D7000. Smaller teeth have been photographed with a binocular microscope. Besides the shark teeth, the bulk samples contained a large amount of teeth and bones of bony fish. They are not the subject of this work.

The The Søvind Marl Formation is generally poor in makrofossil material, but extensive sampling in Søvind Marl Formation in 2020, has revealed a variety of fossils including remains of bony fishes, sharks, rays and chimaera teeth. – Birdsbones, gastropods, bivalves, corals, ostracods, foraminiferas, seaurhcin and calcareous burrows produced by different animals are present both G1 and G2.


The fossils from sharks are mainly teeth, some dermal denticles, coprolites and few vertebrae. The morphology of the dermal denticles is very varied from one family to another and often from one genus to another within a family. Therefore one must be careful when denticle morphology is used to characterize a species. (Cappetta 2012).

Dermal denticles, coprolites and vertebrae are not used to characterize the species in this article.

Presevation of the fossils

Fig. 7: Cropolite from shark. B: Dermal denticle. C: Transparant tooth with fine details.


Sharks from the Søvind Marl Formation

Order Lamniformes Berg 1958
Family Mitsukurinidae Jordan 1898
Genus Mitsukurina Jordan 1898 - Common name DK: Troldhajer / GB: Goblin shark
Mitsukurina sp
.


Fig. 8. Mitsukurina sp.. A, labial view; B, profile; C, lingual view; 10,0 mm high – Bed G2

Family Lamnidae Müller and Henle 1838

Genus Isurolamna Cappetta 1976 - Common name DK: Makrelhajer / GB: Macerel shark
Isurolamna inflata (Casier 1946
)


Fig. 9. Isurolamna inflata. A, labial view; B, profile; C, lingual view; 8,8 mm high – Bed G2

Genus Macrorhizodus Glikman 1964b - Common name DK: Makrelhajer / GB: Macerel shark
Macrorhizodus sp.


Fig. 10. Macrorhizodus sp.
A, labial view; B, profile; C, lingual view; 30,0 mm high – Bed G1
D, lingual view; E, labial view; F, profile; 20,0 mm high – Bed G1


Genus Xiphodolamia Leidy 1877 - Common name DK: Makrelhajer / GB: Macerel shark
Xiphodolamia ensis (Casier 1946
)


Fig. 11. Xiphodolamia ensis. A, anterior tooth, labial view; 20,0mm high B, lateral tooth, lingual view; 8,0mm high – Bed G2

Family Alopiidae Bonaparte 1838
Genus Alopias Rafinesque 1810 - Common name DK: Rævehajer / GB: Thresher sharks
Alopias crochardi Ward 1978


Fig. 12. Alopias sp.. A, labial view; B, profile; C, lingual view; 5,3 mm high – Bed G2
.

Genus Usakias Zhelezko & Kozlov 1999 - Common name DK: Rævehajer / GB: Thresher sharks
Usakias sp.



Fig. 13. Usakias sp. A, labial view; B, profile; C, lingual view; 10,0 mm wide – Bed G1

Family Odontaspididae Müller & Henle 1839
Genus Hypotodus Jaekel 1895 - Common name DK: Sandhajer / GB: Sand Tiger sharks
Hypotodus verticalis


Fig. 14. Hypotodus
sp. A, labial view; B, lingual view; C, profile; 7,3 mm high – Bed G2.

Genus Brachycarcharias Cappetta & Nolf, 2005 - Common name DK: Sandhajer / GB: Sand Tiger sharks
Brachycarcharias lerichei Casier, 1946


Fig. 15. Brachycarcharias lerichei. A, labial view; B, profile; C, lingual view; 10,3 mm wide
– Bed G1

Genus Carcharias Rafinesque 1810 - Common name DK: Sandhajer / GB: Sand Tiger sharks
Carcharias sp.


Fig. 16. Carcharias sp.. A, labial view; B, profile; C, lingual view; upper lateral tooth. 7,3 mm high – Bed G2

Order Carcharhiniformes Compagno, 1977
Family
Scyliorhinidae Gill 1862
Genus
Megascyliorhinus Cappetta & Ward 1977 - Common name DK: Rødhajer / GB: Cat sharks
Megascyliorhinus cooperi


Fig. 17. Megascyliorhinus sp. A, labial view; B, profile; C, lingual view; lateral tooth. 5,3 mm high – Bed G2.

Genus Premontreia Cappetta 1992 - Common name DK: Rødhajer / GB: Cat sharks
Premontreia sp.

Fig. 18. Premontreia sp.. A, labial view; B, lingual view; 2,8 mm high – Bed G2.

Genus Physogaleus Cappetta 1980a - Common name DK: Gråhajer / GB: Sharpnose sharks
Physogaleus secundus Winkler 1876b


Fig. 19. Physogaleus sp. A, labial view; B, lingual view; 6,0 mm high – Bed G1

Family Triakidae GRAY 1851
Genus Triakis MÜLLER & HENLE 1838 -
Common name DK: Gråhajer / GB: Hound sharks
Triakis wardi
CAPPETTA, 1976


Fig. 20. Triakis sp. A, labial view; B, lingual view;
1,4 mm high – Bed G2

Genus Mustelus LINCK 1790 -
Common name DK: Glathajer / GB: Smooth Hound
Mustelus aff. M. vanderhoefti Herman, 1982


Fig. 21. Mustelus
aff. vanderhoefti. A, occlusal face; B, lingual face;
1,4 mm wide – Bed G2

Order Hexanchiformes F. de Buen, 1926
Family Chlamydoselachidae Garman 1884
Genus Rolfodon Cappetta, H. & Morrison, K. & Adnet, S. (2021)
Common name DK: Kravehajer / GB: Frilled sharks
Rolfodon fiedleri


Fig. 22. Rolfodon sp. A, labial view; B, lingual view; C, detail of small cusps on the middle tooth;
D, basal view;. 5,0 mm high – Bed G1. Rolfodon fiedleri. E, labial view; 3,0 mm high Bed G2


Fig. 23. Chlamydoselachus sp. A, labial view; B, lingual view; C,
profile view; 5,5 mm high Bed G2

Family Hexanchidae J. E. Gray, 1851
Genus Heptranchias Rafinesque, 1810 -
Common name DK: Seks- syvgællehajer / GB: Cow sharks
Heptranchias howelli


Fig. 24. Heptranchias howelli. A, Lower tooth, labial view; 10,0 mm wide – Bed G2.
B, Upper tooth, labial view;
5,0 mm high – Bed G2

Genus Hexanchus Rafinesque, 1810 -
Common name DK: Seks- syvgællehajer / GB: Cow sharks
Hexanchus agassizi


Fig. 25. Hexanchus agassizi. A, Lower tooth. lingual view; 12,0 mm wide – Bed G1.
B, Upper tooth, lingual view; 5,0 mm high – Bed G2.

Genus Notorynchus Ayres, 1855 -
Common name DK: Seks- syvgællehajer / GB: Cow sharks
Notorynchus serratissimus
Agassiz, 1843


Fig. 26. Notorynchus sp. A, Lower tooth. Lingual view; 10,0 mm wide – Bed G1.
B, Upper tooth. Lingual view; 5,0 mm high – Bed G1.

Order Squaliformes Compagno, 1973
Family Centrophoridae Bleeker, 1859
Genus Centrophorus J. P. Müller & Henle, 1837 -
Common name DK: Pighajer / GB: Gulper shark
Centrophorus aff. granulosus


Fig. 27. Centrophorus aff. granulosus. A, labial view; B, lingual view; 3,5 mm high – Bed G1.

Family Squalidae Blainville, 1816
Genus Squalus Linnaeus, 1758 -
Common name DK: Pighajer / GB: Spiny dogfish
Squalus minor
Daimeries, 1888


Fig. 28. Squalus sp. A, lingual view; B, labial view; 2,8 mm wide – Bed G1.

Genus Megasqualus Herman 1982 -
Common name DK: Pighajer / GB: Spiny dogfish
Megasqualus sp.


Fig. 29. Megasqualus sp. A, labial view; B, lingual view; 6,1 mm wide – Bed G1.

Family Dalatiidae Gray 1851
Genus Isistius Gill 1865 - Common name DK: Cigarhajer / GB: Cookiecutter shark
Isistius trituratus Winkler 1876b



Fig. 30. Isistius trituratus. A, lingual view; B, labial view. 3,0 mm high – Bed G2.

Genus Eosqualiolus ADNET 2006 - Common name DK: Chokoladehajer / GB: Kitefin shark
Eosqualiolus aturensis


Genus Dalatias Rafinesque, 1810 - Common name DK: Chokoladehajer / GB: Kitefin shark
Dalatias sp.



Fig. 31. Eosqualiolus aturensis. A, labial view; B, lingual view. 1,7 mm high – Bed G2.
Dalatias sp. C. labial view; 1,7 mm high – Bed G1

Family Etmopteridae Fowler, 1934
Genus Etmopterus Rafinesque, 1810 - Common name DK: Lanternhajer / GB: Lantern shark
Etmopterus sp.



Fig. 32.
Etmopterus sp.. A, lingual view; B, labial view. 6,5 mm high – Bed G2.
Etmopterus sp.. C, labial view; D, lingual view. 2,8 mm high – Bed G1.

Genus Orthechinorhinus Adnet 2006 - Common name DK: Lanternhajer / GB: Lantern shark
Orthechinorhinus pfeili
Adnet 2006



Fig. 33. Orthechinorhinus pfeili. A, labial view; B, lingual view; 1,1 mm high – Bed G2.

Genus Orthechinorhinus Adnet 2006 - Common name DK: Lanternhajer / GB: Lantern shark
Orthechinorhinus
sp. Adnet 2006



Fig. 34. Orthechinorhinus sp. A, labial view; B, profile; C, lingual view; 3,0 mm wide – Bed G2.

Order Echinorhiniformes Buen 1926
Family Echinorhinidae Gill 1862
Genus Echinorhinus Blainville 1816
- Common name DK: Sømhajer / GB: Bramble shark
Echinorhinus cf. priscus Arambourg 1952



Fig. 35. Echinorhinus cf. priscus. A, lingual view; B, labial view. 5,3 mm wide – Bed G1.
Echinorhinus cf. priscus. C, Lateral tooth lingual view; D, labial view. 2,2 mm wide – Bed G1.

Order Pristiophoriformes Berg 1958
Family Pristiophoridae Bleeker 1859
Genus Pristiophorus Müller & Henle 1837
- Common name DK: Savhajer / GB: Sawshark
Pristiophorus cf. lanceolatus Davis 1888



Fig. 36. Pristiophorus cf. lanceolatus. Rostral tooth A, labial view; B, lingual view;
C, profile view; 7,0 mm high – Bed G2

Order Orectolobiformes Applegate 1972
Family Orectolobidae JORDAN & FOWLER 1903
Genus Orectoloboides sp. CAPPETTA 1977b
- Common name DK: Tæppehajer / GB: Wobbegong
Orectoloboides sp. CAPPETTA 1977b



Fig. 37. Orectoloboides sp. A, labial view; B, Root from above; 3,3 mm high – Bed G2.
Orectoloboiformes sp. C, labial view; D, lingual view; 2,0 mm wide – Bed G2.

Family Rhincodontidae Garman 1913
Genus Palaeorhincodon HERMAN 1974a
- Common name DK: Hvalhajer / GB: Waleshark
Palaeorhincodon wardi HERMAN 1974a



Fig. 38. Palaeorhincodon wardi. A, labial view; B, lingual view; C, profile view; 1,9 mm high
– Bed G2

Order Heterodontiformes Berg 1937
Family Heterodontidae J. E. Gray, 1851
Genus Heterodontus Blainville, 1816
- Common name DK: Hornhajer / GB: Bullhead sharks
Heterodontus sp.



Fig. 39. Heterodontus sp. A, Toot seen from above ; B, labial view; 13,0 mm wide – Bed G1.


Fig. 40. Heterodontus sp. A, lingual view; B, occlusal view; C, labial view 3,0 mm wide – Bed G2.

Superorder Batomorphii Cappetta 1980b
Order Myliobatiformes Compagno 1973
Superfamily Dasyatoidea Jordan 1888
Family incertae sedis
Genus Coupatezia Cappetta 1982
- Common name DK: Pigrokker / GB: Stingrays
Coupatezia miretrainensis Adnet 2006
a


Fig. 41. Coupatezia sp. A, lingual view; B, distal view; C, labial view.
3,0 mm high – Bed G2.

Order Chimaeriformes Obruchev 1953
Family Chimaeridae Bonaparte 1831
Genus Chimaera Linnaeus 1758
Elasmodus sp. Egerton 1843


Fig.42. Elasmodus sp.?. All from the same tooth. Largest fragment is 10,0 mm.


Sharks from the Fur Formation


Fig.43. The Fur Formation have a negativ serie ekvivalent with the Knudeklint Member. The photo is the top of the Knudeklint Member with a large calcareous bed above volcanic ashlayer minus 11.


Fig.44. The Fur Formation have a positiv serie ekvivalent with the Silstrup Member. The photo is the bottom of the Silstrup Member with a large calcareous bed with volcanic ashlayer plus 25 to 30.


Fig. 45. Stratigraphy of the uppermost Ølst Formation and the Fur Formation. Lithological and sedimentological
logs are modified from Pedersen & Surlyk (1983).


The Fur Formation
The Fur Formation can be seen in many cliffs and quarries in the area. It is a unit of diatomite sediment 60 meters thick consisting of diatoms and clay minerals. The diatomite comprises 2/3 opal tests of diatoms and 1/3 clay, with many volcanic ash layers and some limestone horizons. It is known for its fossil Fish, Birds, Reptiles, Insects, Crustacea, Molluscs, and Land plants and has exceptionally preservation. Fossils of great diversity and unique preservation is most unusual, if not unique, diversity of life from both ocean and land with extremely good preservation of details rarely seen.

More than 200 layers of volcanic ash of predominantly basaltic composition have been found within the Mo-clay of the Fur Formation. 179 of the most prominent ash layers have been numbered with a positiv serie and a negativ serie. The Fur Formation is diveded in Knudeklint Member and Silstrup Member. Comparison with volcanic ash layers in the North Sea indicates that the Mo-clay is coeval with the Sele Formation and Balder Formation. Large teleostean fauna, with earliest members of many living families and diversity several fishes preserved as complete skeletons.



Order Lamniformes L. S. Berg, 1958
Family Odontaspididae Müller & Henle, 1839
Genus Striatolamia GLIKMAN 1964 - Common name DK: Troldhajer / GB: Goblin shark
Striatolamia striata WINKLER 1874a



Fig. 45. 13 teeth from Striatolamia striata 25,0 mm. There are small pieces of cartilage preserved between the teeth throughout the stone.

Family Odontaspididae Müller & Henle, 1839
Genus Palaeohypotodus GLIKMAN 1964 - Common name DK: Sandhajer / GB: Sand Tiger sharks
Palaeohypotodus rutoti WINKELR, 1874b

Odontaspididae sp.? Müller & Henle, 1839


Genus Carcharias Rafinesque, 1810 - Common name DK: Sandhajer / GB: Sand Tiger sharks
Carcharias sp. Rafinesque, 1810



Fig. 46. Palaeohypotodus rutoti. A, labial view; 20,0 mm. Odontaspididae sp. B, labial view; 20,0 mm.
Carcharias sp.. C, labial view; 15,0 mm.

Genus Hypotodus JAEKEL, 1895 - Common name DK: Sandhajer / GB: Sand Tiger sharks
Hypotodus verticalis Cappetta & Nolf, 2005


Genus Sylvestrilamia CAPPETTA & NOLF 2005 - Common name DK: Sandhajer / GB: Sand Tiger sharks
Sylvesterilamia terentides WHITE, 1931

Genus Odontaspis Agassiz, 1838 - Common name DK: Sandhajer / GB: Sand Tiger sharks
Odontaspis winkleri LERICHE, 1905



Fig. 47. Hypotodus verticalis. A, labial view; 15,0 mm. Odontaspis winkleri. B, profile view; 10,0 mm.
Sylvesterilamia terentides. C, lingual view;
20,0 mm.

Family Lamnidae J. P. Müller and Henle, 1838
Genus Isurolamna LERICHE, 1905 - Common name DK: Makrelhajer / GB: Macerel shark
Isurolamna aff. CAPPETTA 1976



Fig. 48. Isurolamna aff. labial view; 12,0 mm.


Sharks from the Ølst Formation



Fig.49. The beach at the locality called Sundby.


Fig.50. The fossilrich unformel Sundbylayer.

Fig.51. The different types of clay on the locality.

The Ølst Formation
East of the old mo-claypit at Mosebjerg on Isle of Mors, there is a type of clay on the beach, which is called Stolleklint Clay. It is deposited as a finely laminated clay, which belongs to the Ølst Formation. The heat period, called the Paleocene – Eocene Thermal Maximum, led to a change in climate affecting animal and plant life in the sea and on land. PETM is represented in Denmark by Stolleklint Clay, and the many well-preserved fossils in the Stolleklint Clay and the overlying Fur Formation enable a comparison of which species thrived during the PETM period, as well as the time immediately after. Stolleklint Clay consists of dark gray-green, laminated clay and contains only a few volcanic ash layers, which include the oldest numbered ash layers from –39 to –33. This clay is in contact with the mo-clay and was deposited in the deepest parts of the sea that covered Denmark in the Eocene. Reduced circulation in the water mass led to oxygen-poor conditions, where 14 - 15 meters of Stolleklint Clay were deposited in the Sundby area.

The transition from Holmehus Clay to Stolleklint Clay contains the boundary between the Paleocene and Eocene periods. The age of the Paleocene − Eocene boundary has been determined by means of geochemical analyzes and is dated to 56 million years. The newly discovered, very rich in fossils, Sundby layer forms the top of the Stolleklint Clay on this part of Mors. The layer at Sundby was found by the author in February 2016, who also observed a similar layer back in 2008. On the stretch in question, there have been collapsed mo-clay cliffs for many years, which have hidden the layer. The Sundby layer, which is the informal name for this very fossil-rich layer, extends over 12 meters along the cliff and the thickness varies, but is a maximum of 9.0 cm, however typically 4.0 cm. A layer found in 2008 was only 2.5 cm in thickness and 2.0 meters in length and could only be seen at extreme low tide. This was the first time the Sundby team was observed.

During the spring of 2016, approx. 650 kg of material, was collected and then finely divided and thoroughly dried. The preparation procedure involves subsequently suspending the dried material in water. After a few days, it is ready for the next step, which is wet sieving. This was done with three different mesh sizes, where the coarse sieve has 2.0 mm meshes, the middle one has 0.5 mm and the very fine one is 0.07 mm. The process causes the fine-grained clay particles to be leached out, which significantly reduces the amount of material. Left are the minerals and fossils. Coprolites (fossilized excrement) from fish constitute the most numerous fossils, and these are typically caught in the coarse sieve. In this fraction, larger shark and bony fish teeth will also be left together with bones and vertebrae from fish, and in rare cases, vertebrae from sea snakes. Once the sieved samples are dry, they are ready to be analyzed so the fossils can be collected using a binocular microscope (Euromex) and roughly sorted.

The many fossils are not clean but are typically coated with various coatings, mostly dolomite stuck to the crown and root of the teeth. To remove this, very carefully scrape the stone with a needle. The teeth and vertebrae cannot be prepared with an engraving pen, as the hammer of this tool is too violent and will cause the fossils to break.



Order: Lamniformes BERG 1958
Family: Mitsukurinidae Jordan, 1898
Genus: Striatolamia Glikman, 1964 - Common name DK: Troldhajer / GB: Goblin shark
Striatolamia macrota (Agassiz, 1838)



Fig. 52. Striatolamia macrota, A, labial view; B, lingual view; C, profile view; 35,0 mm.

Genus: Anomotodon ARAMBOURG 1952 - Common name DK: Troldhajer / GB: Goblin shark
Anomotodon sp.


Fig. 53. Anomotodon
sp., D, lingual view; E, labial view; F, profile view; - 10,0 mm .


FAMILY: Odontaspididae MÜLLER & HENLE 1839
Genus: Brachycarcharias CAPPETTA & NOLF 2005 - Common name DK: Sandhajer / GB: Sand Tiger sharks
Brachycarcharias lerichei (CASIER, 1946)



Fig. 54. Brachycarcharias lerichei, labial view; 15,0 mm.

Genus: Palaeohypotodus GLIKMAN 1964 - Common name DK: Sandhajer / GB: Sand Tiger sharks
Paleohypotodus rutoti (Winkler, 1874)



Fig. 55. Paleohypotodus rutoti C, labial view; 10,0 mm.


Genus: Cretalamna GLIKMAN 1958 - Common name DK: Makrelhajer / GB: Macerel shark

Cretalamna sp.


Fig. 56. Cretalamna sp. A, labial view;, 30,0 mm.

FAMILY: Lamnidae MÜLLER & HENLE 1838
Genus: Isurolamna CAPPETTA 1976 - Common name DK: Makrelhajer / GB: Macerel shark
Isurolamna affinis



Fig. 57. Isurolamna affinis 1 A, labial view; B, lingual view; C, profile view;10,0 mm

Genus: Isurolamna CAPPETTA 1976 - Common name DK: Makrelhajer / GB: Macerel shark
Isurolamna
affinis (Leriche 1905)


Fig. 58. Isurolamna affinis 2, labial view;13,0 mm.

FAMILY: Jaekelotodontidae GLIKMAN 1964
Genus: Jaekelotodus MENNER 1928 - Common name DK: Sandhajer / GB: Sand Tiger sharks
Jaekelotodus robustus (Leriche 1921)



Fig. 59. Jaekelotodus robustus. A, labial view; B, lingual view; C, profile; 35,0 mm high.


Fig. 60. Jaekelotodus sp. A, labial view; 25,0 mm.

ORDER: Carcharhiniformes COMPAGNO 1973
FAMILY: Carcharinidae JORDAN & EVERMANN 1896
Genus: Abdounia CAPPETTA 1980 - Common name DK: Gråhajer / GB: Hound sharks
Abdounia beaugei (ARAMBOURG, 1935)



Fig. 61. Abdounia beaugei. labial view; 6,0 mm.

FAMILY: Carcharinidae JORDAN & EVERMANN 1896
Genus: Physogaleus CAPPETTA 1980 - Common name DK: Gråhajer / GB: Sharpnose sharks



Fig. 62. Physogaleus sp. A, labial view; B, lingual view; 8,0 mm.

FAMILY: Carcharinidae JORDAN & EVERMANN 1896
Genus: Rhizoprionodon Whitley, 1929 - Common name DK: Gråhajer / GB: Sharpnose sharks



Fig. 63. Rhizoprionodon sp. A, lingual view; B,labial view; 6,0 mm.

FAMILY: Triakidae GRAY 1851
Genus: Pachygaleus CAPPETTA 1992 - Common name DK: Gråhajer / GB: Hound sharks
Pachygaleus lefevrei (Daimeries, 1891)



Fig. 64. Pachygaleus lefevrei. A, labial view; B, lingual view; 5,0 mm.

ORDER: Squaliformes GOODRICH 1909
FAMILY: Squalidae BONAPARTE 1834
Genus: Squalus LINNAEUS 1758 - Common name DK: Pighajer / GB: Spiny dogfish



Fig. 65. Squalus sp. A, labial view; B, lingual view; 3,0 mm.

Family: Dalatiidae Gray, 1851
Genus: Oligodalatias Welton, 2016 - Common name DK: Chokoladehajer / GB: Kitefin shark



Fig. 66. Oligodalatias sp. A, lingual view; B, labial view; 5,0 mm.

Family: Dalatiidae Gray, 1851
Genus: Dalatias Rafinesque, 1810 - Common name DK: Chokoladehajer / GB: Kitefin shark



Fig. 67. Dalatias sp. labial view; 5,0 mm.

ORDER: Squatiniformes
FAMILY: Squatinidae BONAPARTE 1838
Genus: Squatina DUMÉRIL 1906 - Common name DK: Havengel / GB: Monkfish
Squatina prima (WINKLER, 1874)



Fig. 68. Squatina prima lingual view; 0,5 mm

Order: Synechodontiformes
Family: Palaeospinacidae Regan, 1906
Genus: Synechodus Woodward, 1888 - Common name DK: ingen navn / GB: no name
Synechodus hesbayensis Casier, 1943



Fig. 69. Synechodus hesbayensis. A, lingual view; B, labial view; 6,0 mm.

Order Pristiophoriformes Berg 1958
Family Pristiophoridae Bleeker 1859
Genus Pristiophorus Müller & Henle 1837 - Common name DK: Savhajer / GB: Sawshark
Pristiophorus cf. lanceolatus Davis 1888
.


Fig. 70. Pristiophorus sp. Two rostral teeth. A, lingual view; B, labial view; 5,0 mm.

Order Myliobatiformes Compagno 1973
Family Dasyatidae Jordan 1888
Genus: Dasyatis - Common name DK: Pigrokker / GB: Stingray


FAMILY: Myliobatidae BONAPARTE, 1838
Genus: Myliobates Schinz, 1822 - Common name DK: Ørnerokker / GB: Eagle Rays



Fig. 71. A, Myliobates sp.; 10,0 mm. B, Sting Ray talespine; 10,0 mm. C, Dasyatis sp.; 2,0 mm



Fig.72. The formations with the types of sharks.


Conclusions
Bulk samples and in situ samples from the sediments of the Ølst Formation, Fur Formation and the Søvind Marl Formation have yielded 46 different genera with 50 species of sharks, two species of ray, and one species chimera. Based on the elasmobranch fauna, the depth was between 50 m in the Early early Ypresian to 400 m in the Early Middel Ypresian, and 200 m in the Late Priabonian.

The fauna is most similar to the fauna from the Middle Ypresian London Clay. The faunas have xx genera and xx species in common. The fauna is also close to the Ypresian/ Lutetian fauna from southwestern France. The faunas have xx genera and xx species in common.

Acknowledgements


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Web sites

http://www.elasmo.com

http://www.fishbase.org

http://www.Shark-References.com

http://www.The Taxonomicon. taxonomy.nl

http://www. users.telenet.be

 
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