Description Lepidotes

1 description

1.1 distinguishing characteristics
1.2 l. elvensis
1.3 l. semiserratus
1.4 l. gallineki
1.5 l. tuberculatus
1.6 l. macrocheirus
1.7 l. occidentalis
1.8 l. haydeni
1.9 l. latifrons

description

fossil of l. elvensis

inhabiting both freshwater lakes , shallow seas, lepidotes typically 30 centimetres (12 in) long. body covered thick, enamelled scales. batteries of peg-like teeth enabled lepidotes crush shells of molluscan prey.

lepidotes 1 of earliest fish in upper jawbones no longer attached jugal bone. allowed jaws stretched tube fish suck in prey greater distance in previous species. system still seen in modern fish, such carp.

lepidotes scales ovular in shape, , 18.5 millimetres (0.73 in) long , 3 millimetres (0.12 in) thick @ thickest point. scales smooth , shiny on external surface, few small depressions scattered toward centre shaped punctures.

distinguishing characteristics

many characteristics identified woodward in 1895, , listed below:

a fusiform trunk moderately compressed;
the fact marginal teeth compressed;
the presence of stouter inner teeth smooth;
ossified ribs;
very large fin-fulera on fins;
that paired fins small;
short , deep dorsal , anal fins;
very robust, smooth or feebly oriented scales;
flank scales not deeper wide;
scales ventrally deep broad;
and presence of inconspicuous dorsal , ventral ridge-scales.

l. elvensis

l. elvensis type species of lepidotes. described ducrotay de blainville in 1818. known complete specimen housed in paris museum of natural history. specimen measures 75 centimetres (2.46 ft) long. specimen upper lias, in bavaria. specimens p. 7406, p. 7407, p. 7408, p. 2014, p. 2054, p. 3529a, p. 3529b, 18992, 18993/94 19662, 32421, , 32422 have been assigned species. external bones of species smooth, have sparsely-placed coarse tuberculations (protuberances). frontal bone more twice length of parietal in specimens. has comparatively narrow marginal symphysis (articulation).

l. semiserratus

this species named agassiz in 1837 , known incomplete remains. has been classified closely related l. elvensis. more elongate l. elvensis, being 4 times long tall. has more sharply angulated sutures between parietals, , parietals proportionally longer. known specimens p. 1127, p. 7409, p. 2012, p. 2012a, p. 3527, p. 3528, p. 3528a, p. 5213, p. 5228, p. 6394, p. 7410, , 35556, upper lias of yorkshire.

l. gallineki

l. gallineki known imperfect internal cast of head , neck, assigned lepidotes michael (1863). estimated length of species 90 centimetres (3.0 ft). eternal bones apparently smooth. on hinder margin, scales smooth , not serrated. specimen rhaetic of upper silesia.

l. tuberculatus

this species, named in 1837 louis agassiz, known single suboperculum (scale-shaped lower opercular bone). includes assortment of unidentified remains stonesfield slate. formation dates bathonian of england. remain can assigned l. tuberculatus suboperculum, other material considered unlikely belong it. specimens provisionally assigned l. tuberculatus woodward p. 471, p. 1111, p. 1111a, p. 3524, p. 7411, 28606, 28607, 30569, 37219, 47141, , 47980.

l. macrocheirus

l. macrocheirus described sir philip egerton in 1845. grow 70 centimetres (28 in) long. trunk of specimens robust, , head measures 1 fifth of total length. in l. elvensis, parietals measure less half of frontals. frontals 3 times long wide. possessed tumid, styliform marginal teeth. inner teeth large , obtuse, there pedicles moderately high. species lacked signs of ring-vertebrae. fin-fulcra large, on medial fins slender. specimens assigned p. 6839, p. 6899, p. 6900, p. 7412, , p. 7413, oxfordian of england.

l. occidentalis

l. occidentalis known 5 ovular scales, described joseph leidy in 1860. enamel surfacing of 5 scales shiny , smooth. largest of scales 100 millimetres (3.9 in) long, , smallest in 50 millimetres (2.0 in).

l. haydeni

l. haydeni species known single, rectangular scale, described leidy in 1860. scale 130 millimetres (5.1 in) long , 89 millimetres (3.5 in) wide. covering of scale small, rectangular squares. root of scale projects toward front of 1 of long sides. specific name honors dr. hayden, discovered many remains, including scale of l. haydeni.

l. latifrons

l. latifrons named , described arthur smith woodward in 1893. known bones , scales head , trunk regions. measured 1 metre (3.3 ft) long. scales of species large , smooth. there no traces of rings on vertebrae. marginal teeth slender , styliform. portion of dentary bears teeth deepened near symphysis. known few, complete specimens, p. 6841, p. 6838, , p. 6840. specimens date oxfordian of huntingdonshire.