Lepidotes (from , 'covered with scales') (previously known as Lepidotus)[Hunterian Museum Geology Collections.
"Lepidotes" .] is an extinct genus of Mesozoic Actinopterygii. It has long been considered a wastebasket taxon, characterised by "general features, such as thick rhomboid scales and, for most of the species, by semi-tritorial or strongly [John G. Maisey, Discovering Fossil Fishes, 1996:150, 152.]
Description
Inhabiting both freshwater lakes and shallow seas,
Lepidotes was typically about long. The body was covered with thick, enamelled scales.
Lepidotes was one of the earliest fish in which the upper jawbones were no longer attached to the jugal. This allowed the jaws to be stretched into a 'tube' so that the fish could suck in prey from a greater distance than in previous species.
Lepidotes scales are ovular in shape, and are long and thick at the thickest point.
Stomach contents of Lepidotes from the Early Jurassic of Germany have found remains of crustacean cuticles, and it is suggested that they fed on relatively soft-bodied prey, which was grasped with the slender marginal teeth, before being crushed by the rounded palatal teeth.
Distinguishing characteristics
Many characteristics were identified by Woodward in 1895, and they are listed below:
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a fusiform trunk only moderately compressed;
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the fact that the marginal teeth are compressed;
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the presence of stouter inner teeth that are smooth;
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ossified ribs;
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very large fin-fulera on all fins;
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that all paired fins are small;
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short and deep dorsal and anal fins;
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very robust, smooth or feebly oriented scales;
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flank scales that are not much deeper than wide;
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scales ventrally nearly as deep as broad;
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and the presence of inconspicuous dorsal and ventral ridge-scales.
Taxonomy
Currently valid species after.
L. gigas
The
type species of the genus, it is known from the Early Jurassic (Toarcian) of Germany.
L. elvensis
L. elvensis was described by Ducrotay de Blainville in 1818. It is known from an almost complete specimen housed in the Paris Museum of Natural History. The specimen measures up to long. The specimen is from the
Upper Lias, in
Bavaria. The specimens P. 7406, P. 7407, P. 7408, P. 2014, P. 2054, P. 3529a, P. 3529b, 18992, 18993/94 19662, 32421, and 32422 have all been assigned to this species. The external bones of this species are smooth, but some have sparsely placed coarse tuberculations (protuberances). The
frontal bone is more than twice the length of the
parietal bone in the specimens. It also has a comparatively narrow marginal
symphysis (articulation).
Other specimens are known from France.
L. semiserratus
This species was named by Agassiz in 1837 and is known from some incomplete remains. It has been classified as closely related to
L. elvensis. It is more elongate than
L. elvensis, being four times as long as tall. It also has more sharply angulated sutures between its parietals, and the parietals are also proportionally longer. It is known from the specimens P. 1127, P. 7409, P. 2012, P. 2012a, P. 3527, P. 3528, P. 3528a, P. 5213, P. 5228, P. 6394, P. 7410, and 35556, all from the Upper Lias of
Yorkshire, England
L. buelowianus
Known from the Early Jurassic of (Toarcian) Germany.
Reassigned species
"Lepidotes" latifrons from the Middle-Late Jurassic of England has been reassigned to the genus
Isanichthys. Many other European species from the Late Jurassic-Early Cretaceous have been reassigned to
Scheenstia.
