Fig 1.
Surface stratigraphy of Alabama and Mississippi Peritresius localities.
Upper Cretaceous surface exposures in both Alabama and Mississippi and the localization of discussed Peritresius specimens.
Fig 2.
Generalized Santonian through Maastrichtian surface stratigraphy in west and central Alabama and east Mississippi.
Stratigraphy follows that of Mancini et al. [11] and Dockery [12]. Planktonic foraminiferal zones after Caron [13].
Table 1.
List of relevant stratigraphic units, localities, and specimens.
(AL) Alabama. (MS) Mississippi. Lithologic descriptions and depositional environments follow Raymond et al. [14] and Puckett [15].
Fig 3.
Peritresius martini sp. nov., carapace, ALMNH 6191 (holotype) from the upper Campanian of Alabama, USA.
(1) carapace in dorsal view and plastron in ventral view; (2) left peripherals 3–6, 9, & 11 in posterior view; (3) 10X magnified view of the dorsal surface of right peripheral 10; (4) hypothetical reconstruction of the complete shell with the preserved elements shown in gray. Abbreviations: p, peripheral; pyg, pygal; spg, suprapygal.
Fig 4.
Peritresius martini sp. nov., plastron, ALMNH 6191 (holotype) from the upper Campanian of Alabama, USA.
(1) Plastron in ventral view; (2) hypothetical reconstruction of the plastron with the preserved elements shown in gray. Abbreviations: epi, epiplastron; hyo, hyoplastron; hypo, hypoplastron; xiphi, xiphiplastron.
Fig 5.
Peritresius martini sp. nov., pelvis, ALMNH 6191 (holotype) from the upper Campanian of Alabama, USA.
Pelvis in dorsal view. Abbreviations: isc, ischium; pip, posterior iliac process; tf, thyroid fenestra.
Fig 6.
Peritresius ornatus, slab specimen, ALMNH 8988 from the upper Campanian of Alabama, USA.
(1) 10X magnified view of dermal sculpturing present on all preserved elements. (2, 4) slab in dorsal view. (3, 5) slab in ventral view. Abbreviations: C, costal; N, neural.
Fig 7.
Peritresius ornatus neurals from the Campanian-Maastrichtian of Alabama and Mississippi.
(1) MMNS 5876; (2) ALMNH 5497; (3) MMNS 5274; (4) MMNS 5710; (5) MMNS 8632.4. All elements shown in (A) anterior, (B) ventral, (C) dorsal, and (D) 10X magnified views.
Fig 8.
Peritresius ornatus peripheral and costal material from Alabama and Mississippi.
(1) MMNS 4547 in: (A) dorsal, (B) ventral, and (C) posterior views; (2) MMNS 4003 in dorsal view; (3) ALMNH 6256 in: (A) dorsal, (B) ventral, and (C) posterior views; (4) RMM 5741 in dorsal view; (5) MMNS 5102 in: (A) dorsal and (B) ventral views; (6) MMNS 5533 in: (A) dorsal and (B) ventral views.
Fig 9.
Time-calibrated, strict consensus phylogeny of select fossil and extant Testudine species.
Bootstrap values (left) and decay indices (right) are shown for each node; CI = 0.586; RI = 0.671; Branch lengths for crown cheloniid species taken from Cadena and Parham [28].
Fig 10.
Toxochelys weeksi, plastron, USNM.V.20110 (holotype) from the upper Campanian of Tennessee.
Plastron in ventral view with associated measurements. Dashed lines represent areas historically interpreted as fontanelles and the black arrow indicates a broken edge. Courtesy of Smithsonian Institution. Photograph by A. Millhouse.
Fig 11.
Biostratigraphy and paleobiogeography of Late Cretaceous chelonioid sensus stricto species of North America.
Localities and taxon ranges for fossil occurrences were taken from the literature as follows: Nichollsemys baieri from Brinkman et al. [64], Porthochelys laticeps from Hirayama [1], Toxochelys latiremis from Hirayama [1] and this study, Ctenochelys stenoporus from Hirayama [1], Prionochelys nauta from Hirayama [1], Toxochelys moorevillensis from Hirayama [1], Ctenochelys acris from Gentry [29], Thinochelys lapisossea from Hirayama [1], Zangerlchelys arkansaw from Hirayama [1], Peritresius martini from this study, Peritresius ornatus from Baird [4] and this study, Euclastes wielandi from Parham [65], and Catapleura repanda from Hirayama [66]. Age justifications are provided as supporting information (S4 File). Base map obtained and modified from the USGS National Map Viewer.