Protacrodus cf. serra Ginter, Hairapetian, and Klug, 2002
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https://doi.org/ 10.5281/zenodo.13741212 |
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https://treatment.plazi.org/id/954A87EC-2C1E-3360-FF80-FA7078C07EA3 |
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treatment provided by |
Felipe |
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scientific name |
Protacrodus cf. serra Ginter, Hairapetian, and Klug, 2002 |
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Protacrodus cf. serra Ginter, Hairapetian, and Klug, 2002
Fig. 4C.
Material.—One tooth.
Description.—The only tooth of this type has five largely separate cusps in the crown which is strongly compressed labio−lingually. The base of this specimen is arched. Such specimens can be found among the material of P. serra from the type area and horizon (upper Famennian of the Anti−Atlas; compare Ginter et al. 2002: pl. 11: 1).
Protacrodontidae ? gen. et sp. indet.
Figs. 4D, E, 6C View Fig
Material.—Three teeth.
Description.—We present here three rather different crushing teeth. The two larger specimens are extremely elongated mesio−distally with one or two major, pyramidal cusps and a series of smaller lateral, largely fused cusps of similar size. The crown is ornamented with coarse, wavy cristae directed towards the apices of the cusps or vertical in the areas where no cusp can be distinguished. A peculiar festoon−like ornamentation, in some places forming honeycomb cells, covers the crown−base interface. The base is typically euselachian.
The largest tooth ( Fig. 6C View Fig ; mesio−distal dimension of preserved part about 7 mm) has extensively fused lateral cusps, forming together a long ridge, lowering laterally, whereas the tips of the cusps in the smaller tooth ( Fig. 4E; about 3 mm) are clearly discernible and the major cusp seems to be more prominent. The larger tooth is almost straight, but the mesio−distal axis of the smaller one turns about 20 ° at the major cusp.
The side with two major cusps in the largest tooth is apparently complete. If so, the tooth is extremely asymmetrical. The same side in the smaller tooth is broken, so it is impossible to say whether there was only one (preserved) major cusp or two, as in the other specimen, and if the tooth continued further.
The third, smallest tooth ( Fig. 4D; 2.4 View Fig mm mesiodistally) is virtually symmetrical, like typical protacrodont teeth. The lateral cusps, present on both sides, are fused up to the two−thirds of their height. The crown ornamentation is almost identical to that in the second tooth. The characteristic festoon−like sculpture near the base is very delicate on the lingual face, and on the labial face it shows only as a double, wavy line.
Remarks.—The festoon−like (or “coarse reticulate” sensu Long and Hairapetian 2000) pattern of ornamentation of the basal part of the crown is common in several Famennian protacrodontids. Long and Hairapetian (2000) presented it as a diagnostic feature of the genus Dalmehodus ; it also occurs in crushing teeth from Utah ( Ginter 2001: fig. 6D, E, H), on the lingual side of several teeth of Deihim mansureae from Iran ( Ginter et al. 2002: text fig. 10G), and on one of the Moroccan teeth referred to as “ Protacrodontidae cf. Deihim mansureae ” by Ginter et al. (2002: pl. 6: J). The latter authors suggested it to be merely a result of intersection between vertical cristae and the growth lines of the crown, but whereas in the case of the teeth from Utah and the labial side of the smallest tooth from Muhua this appears to be true, there are also specimens (e.g., Fig. 4E) in which the relation of this sculpture to the coronal cristae is less obvious.
If our identification of the three described teeth as belonging to the same species is correct, this would mean that the level of heterodonty is very high here. The third, symmetrical tooth could represent the anterior part of the dentition, the second, longer tooth could come from the anterolateral tooth families and the first tooth with fused cusps could be situated in the posterior position, as a “molar”. Judging from the positions of teeth within the dentition of the upper Pennsylvanian Hamiltonichthys ( Maisey 1989: figs. 26, 27), it can be assumed that the shorter part in asymmetrical teeth is directed mesially and the longer branch—distally. The symmetrical teeth in Hamiltonichthys occur on the shorter side of asymmetrical ones.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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