Archosargus undetermined
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publication ID |
https://doi.org/ 10.5070/P939056976 |
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publication LSID |
lsid:zoobank.org:pub:13E6A6E9-DE0F-4C71-BE40-2957F48D9F70 |
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persistent identifier |
https://treatment.plazi.org/id/03DF0849-4126-FFCC-3934-FDA2FD82FA5E |
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treatment provided by |
Felipe |
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scientific name |
Archosargus undetermined |
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FIG. 11K–Y View Figure 11
Type species — Sparus probatocephalus, Walbaum 1792 View in CoL , Recent.
Referred specimens (n=73) —SC2007.36.111 (nine teeth) SC2007.36.146 (15 teeth), SC2007.36.163 (three teeth), SC2007.36.193 ( Fig. 11X–Y View Figure 11 ), SC2007.36.200 ( Fig. 11N–Q View Figure 11 ), SC2015.29.192 (20 teeth), SC2015.29.192 ( Fig. 11V–W View Figure 11 ), SC2015.29.194, SC2015.29.196 (12 teeth), SC2015.29.197 ( Fig. 11K–M View Figure 11 ), SC2015.29.205 (seven teeth), SC2015.29.217, SC2015.29.219 ( Fig. 8R–U View Figure 8 ), SC2015.29.220.
Description —Three tooth morphologies were identified in our sample, including molariform ( Fig. 11K–M View Figure 11 ), incisiform ( Fig. 8N–U View Figure 8 ), and pharyngeal (Fig. V–Y). The molariform teeth have a circular to oval occlusal outline and a domed crown. The height of the teeth is nearly equal to the width. The occlusal surface is covered with enameloid, but the enameloid does not extend to the tooth base. The sides of the crown are straight to weakly convex and basally constricted where the root begins. Smaller teeth are less constricted than large ones.In basal view, the teeth have a deep, oval, and medially located pulp cavity that is framed by a thick wall of dentine.
The incisiform teeth measure less than 3.0 mm in height and up to 2.0 mm in width. In profile they are similar in appearance to the pharyngeal teeth described below, but they are much wider mesio-distally. The labial face ranges from broad and flat to weakly convex, but the lingual face bears a large, posteriorly directed boss that is narrower than the labial crown width. The upper half of the crown is developed into a broad transverse crest, which is often worn (through in vivo use) such that the internal dentine is exposed and framed by a thick layer of enameloid. The enameloid is smooth. The crown base is constricted at the point where the root begins. The root is comprised of dentine and is smaller in area than the crown.
The pharyngeal teeth are small, measuring less than 2.0 mm in total height and as much as 0.25 mm in width (mesio-distal). They are highly laterally compressed but of equal apico-basal thickness. In profile the crown is antero-posteriorly wide at the lower half, but the upper part is developed into a conical, posteriorly curved cusp. The labial and lingual tooth margins are rounded. The labial margin is convex, whereas the lingual margin is sinuous due to the posteriorly expanded lower portion of the crown. The base of the crown tapers slightly at the origin of the root.
Remarks —We compared the teeth described above to those of the extant sparids Archosargus probatocephalus ( Walbaum, 1792) (MSC 42584) and Calamus leucosteus , and the sciaenid Pogonias cromis (MSC 42612). Within the Ashley Formation sample described above, the pharyngeal teeth are comparable to those occurring along the margins of the A. probatocephalus pharyngeal plates. This Archosargus - type pharyngeal morphology appears to be lacking in the C. leucosteus and P. cromis specimens we examined.
The complex morphology of the Ashley Formation incisiform teeth compares very favorably to those of extant Archosargus but is very different from other sparid incisiform teeth described below. The molariform teeth also conform to large crushing-type teeth on A. probatocephalus pharyngeal plates. When compared to the other similar teeth identified in our Ashley Formation sample, the Archosargus sp. molariform teeth have a deeper and more oval pulp cavity than on Albula sp. ,? Calamus sp. and? Pogonias sp. In addition, the crown height to width ratio is greater than on the other taxa, and the teeth are more basally constricted than those of? Calamus sp. and? Pogonias sp. Finally, the crown is more dome-shaped in profile view than those of Albula sp. With all three of these tooth morphologies occurring within the dentition of the Recent A. probatocephalus examined, it is assumed that all three morphologies identified our Ashley Formation sample belong to the same taxon.
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