The Lower Eocene (Ypresian) Chondrichthyes from Egem, Belgium

Introduction   p. 5
Materials and Methods   p. 5
Terminology   p. 6
Abbreviations   p. 6
Geological overview of the Ampe Quarry at Egem, Belgium   p. 7
Tielt Formation   p. 8
Kortemark Silt Member   p. 8
Egemkapel Clay Member   p. 9
Hyon Formation   p. 9
Egem Sand Member   p. 9
Gentbrugge Formation   p. 10
The Pittem Clay Member   p. 10
Systematic Palaeontology   p. 11
Order Hexanchiformes Buen, 1926   p. 11
Family Hexanchidae Grey, 1851   p. 11
Hexanchus agassizi Cappetta, 1976   p. 11
Weltonia burnhamensis Ward, 1979   p. 13
Notorynchus serratissimus Agassiz, 1843   p. 15
Order Squaliformes Goodrich, 1909   p. 17
Family Squalidae Bonaparte, 1834   p. 17
Squalus minor Leriche, 1905   p. 17
Family Dalatiidae Grey, 1851   p. 20
Isistius trituratus (Winkler, 1874)   p. 20
Order Squatiniformes Buen, 1926   p. 20
Family Squatinidae Bonaparte, 1838b   p. 20
Squatina crassa Daimeries, 1889   p. 21
Squatina prima (Winkler, 1874)   p. 21
Order Heterodontiformes Berg, 1937   p. 25
Family Heterodontidae Grey, 1851   p. 25
Heterodontus vincenti (Leriche, 1905)   p. 26
Order Orectolobiformes Compagno, 1973   p. 41
Family Parascylliidae Gill, 1862b   p. 41
Pararhincodon ypresiensis Cappetta, 1976   p. 41
Family Brachaeluridae Cappetta, 1987   p. 43
Eostegostoma angustum (Nolf & Taverne) in Herman, 1977a   p. 43
Family Ginglymostomatidae Gill, 1862   p. 44
Nebrius thielensis (Winkler, 1874)   p. 44
Protoginglymostoma ypresiensis (Casier, 1946)   p. 47
Family Rhincodontidae Garman, 1913   p. 47
Paleorhincodon wardi Herman, 1974   p. 47
Species List   p. 49
Acknowledgements   p. 50
References   p. 51

Fossil teeth from 13 chondrichthyan species spread over the Hexanchiformes, Squaliformes, Squatiniformes, Heterodontiformes and Orectolobiformes orders are displayed and for most a morphological analysis provides a correct determination on the tooth category. The recovered fossils consist of mainly marine specimen like isolated teeth, vertebrae, tooth plates, spines, invertebrates and even land based plant remains. Finds from land mammals and reptiles, and birds were very rare. 

The extinct species Squalus smithi Herman, 1982b is redefined as a synonym for Squalus minor Daimeries, 1888, the validity of Squatina crassa Daimeries, 1889 is reinstated and the occurrence of Heterodontus in the North Sea basin during the Eocene is revised to one single species (see Migom & Hoedemakers in prep.). Future volumes will comprise studies on other elasmobranchii and holocephali.

Keywords: Chondrychthyes, Elasmobranchii, Eocene, Lower Ypresian, Egem, Ampe quarry