Phyllodus paulkatoi Estes & Hiatt, 1978
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publication ID |
https://doi.org/ 10.4202/app.01117.2023 |
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persistent identifier |
https://treatment.plazi.org/id/03E18741-1308-EF0D-DCD7-FDBEFF7DFCB6 |
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treatment provided by |
Felipe |
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scientific name |
Phyllodus paulkatoi Estes & Hiatt, 1978 |
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Phyllodus paulkatoi Estes & Hiatt, 1978
Fig. 3C View Fig .
Material.—One incomplete tooth plate (RU-EFP-04165-1), partially encased in concretion, found as float, and an isolated tooth (RU-EFP-04165-2) from the Hornerstown Formation. The presence of mature, bright green glauconite within the concretion matrix suggests that the tooth plate almost certainly derives from the Hornerstown Formation. All from the Maastrichtian–Danian Hornerstown Formation, Edelman Fossil Park, Mantua Township, New Jersey, USA.
Description.—All teeth within the partial tooth plate are circular in occlusal view, tightly packed, and phyllodont. The teeth are superimposed in directly successional stacks, being up to three deep (as preserved). Each tooth is ~ 3 mm in diameter, very flat, and thin when viewed in profile. Two of the “highest” exposed crowns exhibit a finely punctate occlusal surface texture, whereas four of the other crowns exposed slightly deeper within the tooth plate exhibit intricate, radially-oriented ridges which anastomose with one another, indicating they were each covered by another tooth which is not preserved. RU-EFP-04165-2 exhibits the same round outline in occlusal view and flat shape in profile as those in the partial tooth plate; its occlusal surface is covered by similarly faint, radially-oriented, anastomosing ridges, indicating that it is an unerupted replacement tooth.
Remarks.—Stacking of teeth in direct succession identifies RU-EFP-04165-1 as pertaining to a phyllodontine fish, differentiating it from paralbulines ( Estes 1969). The very flat, thin shape of the teeth in profile is more consistent with the genus Phyllodus than Egertonia (the only two genera within Phylodontinae; Halliday et al. 2016), the latter of which tends to exhibit more domed teeth with thicker enamel ( Estes 1969). Among the two currently-recognized species of Phyllodus , the consistently-round shape of all tooth stacks and degree of punctate sculpturing on the occlusal surface in the tooth plate are both consistent with Phyllodus paulkatoi . In contrast, the teeth of Phyllodus toliapicus Agassiz, 1839 , are slightly smoother and both the basibranchial and parasphenoid tooth plates possess transversely-elongate teeth in their central rows ( Estes and Hiatt 1978).
Phyllodus paulkatoi was previously only known from the Maastrichtian and Danian of Montana ( Estes and Hiatt 1978) and the Maastrichtian of Wyoming ( Brinkman et al. 2021). Recovery of two specimens from the Hornerstown Formation at Edelman Fossil Park extends its geographic range to the eastern coast of North America at this time (Maastrichtian–Danian).
Stratigraphic and geographic range.— Upper Cretaceous (Maastrichtian) to Paleocene (Danian) of Montana, New Jersey, and Wyoming in USA .
Ichthyodectiformes Bardack & Sprinkle, 1969
Genus Saurocephalus Harlan, 1824
Type species: Saurocephalus lanciformis Harlan, 1824 , Campanian , Kansas, USA .
Saurocephalus lanciformis Harlan, 1824
Fig. 3E View Fig .
Material.—One tooth (RU-EFP-04151) from the lower Hornerstown Formation above the MFL, Danian, Edelman Fossil Park, Mantua Township, New Jersey, USA.
Description.—The crown is triangular and strongly laterally compressed, giving it a flat, spatulate form. Its tip is directed apically and forms a roughly 55° angle in labial view. A sharp, unserrated carina is present on both cutting edges of the crown. The base of the crown, which is slightly wider than the root, curves smoothly and evenly to join it. The root is straight, hollow, ~2.5 times as tall as wide, gradually tapers toward its base, and exhibits a faint, longitudinal groove on both flat sides; these grooves give the root an hourglass cross section when viewed basally.
Remarks.—The broad, laterally-compressed shape of the crown and length of the root identify this tooth as belonging to a saurodontid fish ( Bardack and Sprinkle 1969; Stewart 1999). Among the three genera of saurodontids, the flat, broad character of the crown is most similar to that of Saurocephalus ( Hays 1830) . In Saurodon and Prosaurodon , the teeth are more acutely lanciform ( Hays 1830; Stewart 1999). Additionally, the teeth of Prosaurodon are inclined anteriorly and exhibit a more ovoid shape in cross section ( Stewart 1999; Everhart 2005), and the crown in Saurodon leanus Hays, 1830 , appears more cuspate/curved (cf. Hays 1830: pl. 16: 7, 8). Of the two known species of Saurocephalus , only S. lanciformis has been described from North America (Friedman 2012). The only other species, S. woodwardii Davies, 1878 , known exclusively from Europe ( Netherlands and Belgium), is based on disparate geographic occurrences compared to known specimens of S. lanciformis rather than an anatomical diagnosis. For this reason, Friedman (2012) noted that S. woodwardii may be a synonym of S. lanciformis and that detailed taxonomic review of specimens assigned to the genus is needed.
Fossils of Saurocephalus lanciformis have been recovered from Campanian strata in the Western Interior and Gulf Coast of the United States (Friedman 2012; Irwin and Fielitz 2013). The only previous report of a saurodontid from New Jersey was the description of a partial skull of Saurodon leanus collected from the Navesink Formation in Pensauken Creek near Moorestown ( Hays 1830; Fowler 1911). The tooth described here constitutes the first record of Saurocephalus from northeastern North America and the first record of the genus in the Danian, thus extending the geographic range of S. lanciformis (from the Campanian) and demonstrating that it survived briefly into the early Paleocene.
Stratigraphic and geographic range.— Upper Cretaceous Campanian ) to lower Paleocene (Danian) of Arkansas, Kansas, and New Jersey in USA , and Russia.
Genus Atractosteus Rafinesque, 1820
Type species: Atractosteus spatula Lacépède, 1803 , Recent , southern USA .
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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Phyllodus paulkatoi Estes & Hiatt, 1978
| Boles, Zachary M., Ullmann, Paul V., Putnam, Ian, Ford, Mariele & Deckhut, Joseph T. 2024 |
Phyllodus paulkatoi
| Estes & Hiatt 1978 |
Ichthyodectiformes
| Bardack & Sprinkle 1969 |
Saurodontidae
| Cope 1871 |