Rhinobatos sp.
tooth of Rhinobatos sp. height of tooth = 1,5 mm ENCI-quarry near Maastricht / Lichtenberg horizon
Occurence: rare  Due to the small size of these teeth (1-2 mm) bulk sampling collecting methods are required to collect them.

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There is discussion about the exact systematic position of "Squatirhina" . Arambourg (1952) and Herman (1977) suggested a relationship with the Orectolobiformes (nurse and carpet sharks), according to Cappetta (1987) "Squatirhina" should be placed among the rhinobatoid rays.

Two different types can be found in the Maastrichtian of the Netherlands and Belgium: one with a short cusp, the other with a long cusp. According to Herman (1977) these two types might reflect a sexual dimorphism within one species (= different tooth shapes in male and female individuals) .

Squatirhina kannensis (Herman 1977)
tooth of Squatirhina kannensis (type with short narrow cusp) height of tooth = 3 mm ENCI-quarry near Maastricht / Lichtenberg horizon
tooth of Squatirhina kannensis (type with long cusp) height of tooth = 5 mm ENCI-quarry near Maastricht / Lichtenberg horizon
Occurence: common

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Like the modern sawfishes (family Pristidae) the cretaceous Sclerorhynchidae also had a rostrum, a term indicating their long flat snout armed with a row of spines (the "rostral teeth") on both sides. Unlike the rostral teeth of modern pristidae, the rostral teeth of the cretaceous Sclerorhynchidae have a cap with smooth enameloid.

In contrast to these rostral teeth which may reach a length of several centimeters, the oral teeth are much smaller (only a few millimeters).

In the Maastrichtian of the Netherlands the Sclerorhynchidae are represented by the species Ganopristis leptodon (synonym: Sclerorhynchus leptodon). Rostral teeth as well as oral teeth can be found (due to their small size, the latter are much harder to find and require bulk sampling techniques to collect them).

Ganopristis leptodon (Arambourg 1935)
rostral tooth of Ganopristis leptodon length of tooth = 28 mm ENCI-quarry near Maastricht / Lichtenberg horizon
oral tooth of Ganopristis leptodon width of tooth = 4 mm ENCI-quarry near Maastricht / Lichtenberg horizon
Occurence: less common (rostral teeth) to relatively rare (oral teeth)

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Rhombodus binckhorsti (Dames 1881)
oral tooth of Rhombodus binckhorsti (juvenile specimen) width of tooth = 5 mm ENCI-quarry near Maastricht / Lichtenberg horizon
Occurence: rare

? Rhombodus sp.
dermal thorn of ? Rhombodus sp. height of denticle = 5 mm ENCI-quarry near Maastricht / Lichtenberg horizon	The skin of modern sharks and rays is covered with "placoid scales", microscopic small tooth-like structures embedded in the skin, giving it a rough surface. Bigger placoid scales are called "dermal denticles" and can be found on the back and tail of rays - the size of these dermal thorns can vary from a few mm to more than 1 cm - and are also known from fossils. A fossil very similar like this - from the Maastrichtian of Morocco - is figured by Arambourg (1952) on plate XXIX (fig. 57) and is identified as a dermal denticle of "Rhombodus meridionalis" . (Note that my specimen has no enameloid cap and that a small part of the top is missing)
Occurence: rare

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Coupatezia fallax (Arambourg 1952)
oral tooth of Coupatezia fallax height of tooth = 2 mm ENCI-quarry near Maastricht / Lichtenberg horizon
Occurence: less common

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Last updated September 18th, 2006