taxonID	type	description	language	source
03FF265F4F48766AB378F8C7FBD8F82D.taxon	materials_examined	Type species: Palacrodon browni Broom, 1906, Aliwal North, South Africa, Middle Triassic.	en	Kligman, Ben T., Marsh, Adam D., Parker, William G. (2018): First records of diapsid Palacrodon from the Norian, Late Triassic Chinle Formation of Arizona, and their biogeographic implications. Acta Palaeontologica Polonica 63 (1): 117-127, DOI: 10.4202/app.00426.2017, URL: http://dx.doi.org/10.4202/app.00426.2017
03FF265F4F49766CB044FB09FE50FA96.taxon	description	Fig. 2. Material. — PEFO 37247, fragment of a right maxilla with two complete teeth and two partial teeth. Obtained from PFV 396, the “ coprolite layer ” near Billing’s Gap in Petrified Forest National Park, Arizona, USA. A fossiliferous light green matrix-supported siltstone in the upper Blue Mesa Member of the Chinle Formation, between 223.036 ± 0.059 and 220.123 ± 0.068 Ma (Ramezani et al. 2011). These dates place the occurrence within the Adamanian Land Vertebrate Estimated Holochron (Martz and Parker 2017; previously the Adamanian Land Vertebrate Faunachron of Lucas and Hunt 1993). Detailed locality information is on file at Petrified Forest National Park and available to qualified researchers. Diagnosis. — Diapsid reptile with bulbous, labio-lingually broadened teeth that are ankylosed directly onto the apex of the jaw with acrodont implantation. Teeth are fused to each other mesiodistally along their entire labiolingual width. The margin of each tooth is flanged on its mesial and distal edges. The teeth have a pyramidal lateral profile with concave mesial and distal crown surfaces. Wear facets are present on the apex of each tooth. Tooth margins form a rectangular profile in occlusal view, and have a trapezoidal profile in anteroposterior view. This combination of characters is unique to Palacrodon browni. Description. — PEFO 37247 is a partial right maxilla with four preserved teeth, two of which are complete, and two are largely fragmented. PEFO 37247 has an anteroposterior length of 7.2 mm, a greatest dorsoventral depth of 3.8 mm, and a mediolateral width of 1.1 mm. The maxilla is incomplete along its dorsal margin and both anteroposterior ends because of damage during processing. Two nutrient foramina with a width of 0.5 mm are located on the labial side of the maxilla and open into a vacuity in the interior of the element (Fig. 2 B 1); these foramina are similar to those found on BP / 1 / 5296. A slot opens posteromedially at the posterodorsal end of the bone, likely where the jugal articulated onto the maxilla. Four teeth are present, with the two middle ones being complete. One of the two complete teeth is larger than the other (Table 1). This size difference indicates that the larger tooth was further back in the jaw than the smaller one (Gow 1992, 1999). The teeth are ankylosed directly onto the apical surface of the dentary in an acrodont fashion. There is a row of small pits each with a diameter of 0.01 mm where the labial and lingual margins of the base of each tooth meets the maxillary bone (Fig. 2 C). The tooth bases bulge out 0.3 mm from the labial and lingual margins of the maxilla, making the teeth wider labiolingually than the maxilla itself. PEFO 37247 is identical to SAM-PK- 6215 in that the teeth are pyramidal in lateral view and each complete tooth has a flat lemniscate wear facet on its apical surface (Fig. 2 A 1), cutting through the thin layer of enamel that covers the tooth surface and exposing the dentine center of the tooth. The wear facets on PEFO 37247 are nearly identical in shape to those found in the partial dentary of BP / 1 / 5672. Concave shelves are present on the mesial and distal sides of the wear facet on each tooth, extending two-thirds of the way down the tooth (Fig. 2 B 2). A flange extends below the mesial and distal shelves on each tooth to meet the flange of the adjacent tooth. The teeth contact each other mesiodistally and the respective flanges are firmly fused together along this line of contact (Fig. 2 A 2); three such tooth-to-tooth contacts are present in this specimen. Stratigraphic and geographic range. — Currently known from Cynognathus Assemblage Zone rocks (South Africa), the lower Fremouw Formation (Antarctica), and the Chinle Formation (Arizona, USA).	en	Kligman, Ben T., Marsh, Adam D., Parker, William G. (2018): First records of diapsid Palacrodon from the Norian, Late Triassic Chinle Formation of Arizona, and their biogeographic implications. Acta Palaeontologica Polonica 63 (1): 117-127, DOI: 10.4202/app.00426.2017, URL: http://dx.doi.org/10.4202/app.00426.2017
03FF265F4F4E766EB0B1FAB9FE41FE92.taxon	description	Fig. 3.	en	Kligman, Ben T., Marsh, Adam D., Parker, William G. (2018): First records of diapsid Palacrodon from the Norian, Late Triassic Chinle Formation of Arizona, and their biogeographic implications. Acta Palaeontologica Polonica 63 (1): 117-127, DOI: 10.4202/app.00426.2017, URL: http://dx.doi.org/10.4202/app.00426.2017
03FF265F4F4E766EB0B1FAB9FE41FE92.taxon	materials_examined	Material. — MNA V 3684, fragment of marginal dentition with two complete teeth; MNA V 11247, isolated tooth. Obtained from MNA 207 - 2, the Placerias Quarry, St. John’s, USA. A fossiliferous horizon with abundant macrovertebrate and microvertebrate bones and carbonaceous nodules in a clay rich mudstone matrix (Fiorillo et al. 2000) from the Chinle Formation, dated to 219.39 ± 0.16 Ma based on U-Pb detrital zircon dates (Ramezani et al. 2014). These dates place the occurrence solidly in the Adamanian Land Vertebrate Estimated Holochron (Martz and Parker 2017). Detailed locality information is on file at Museum of Northern Arizona and is available to qualified researchers. Diagnosis. — Differs from Palacrodon browni in having teeth that have a bicuspid apex and a mesially recurved labial profile. The base of the distal shelf is concave in labial view, halfway towards the apex becoming convex to the apex of the tooth. The mesial tooth shelf is concave in labial view, and the apical edge of the tooth reaches an angle just greater than 90 °. The labiolingually-broadened apex of the tooth possesses two cusps, one on the labial side, and one on the lingual side. These cusps are joined by a narrow ridge that forms a saddle between the cusps in mesiodistal view. Description. — MNA V 3684 is a tooth-bearing fragment of a maxilla or dentary (Fig. 3 A). The assignment to either element is difficult because the bone is broken along all margins except for the tooth-bearing surface, and will be referred to as a dentary in this description. Two complete teeth are preserved. The jaw fragment has a mesiodistal length of 7.5 mm, and a labiolingual width of 3.6 mm, and is incomplete on along its labial, lingual, ventral, posterior, and anterior surfaces. Measurements of the teeth are found in Table 1. Two teeth are present. One of the two complete teeth is larger than the other (Table 1). Palacrodon teeth increase in size distally, indicating that the larger tooth was further distal in the jaw than the smaller one (Gow 1992, 1999). The teeth are ankylosed directly onto the apical surface of the dentary in an acrodont fashion, and are bulbous, bulging out slightly from the margins of the jaw. No tooth root is apparent in the jaw where it is fractured less than 1 mm below the tooth bases and it can be assumed that if rooting is present, it is very shallow. There is a row of small pits on the lingual side of the distal tooth, each with a diameter of 0.01 mm where the lingual margin of the tooth base meets bone, similar to the pitting seen in PEFO 37247 (Fig. 2 C). The teeth are rectangular in occlusal view with most of their surface taken up by mesial and distal shelves that meet at the apex of the tooth. The base of the mesial shelf starts as a flange that meets and fuses to the tooth distal to it, and is concave in labial view. Halfway towards the apex the shelf becomes convex. The distal tooth shelf is concave in labial view and reaches an angle just greater than 90 ° with respect to the jaw, creating a recurved profile in labial view. The labiolingually-broadened apex of the teeth possesses two cusps, one on the labial side, and one on the lingual side Fig. 3 A 2). These cusps are joined by a narrow ridge that forms a concave saddle between the cusps in mesial view Fig. 3 B 1). The mesial and distal shelves are concave basally, with maximum concavity at the labiolingual midline of the teeth forming a slight basin. The presence of these basins on the mesial and distal sides of the apex creates a constriction of the apical ridge at the labiolingual midline of the teeth, and the ridge expands to its widest at the cusps on either side of the apex. The apex of the posterior tooth exhibits a lemniscate wear facet spreading across both cusps and the saddle between them. The apex of the anterior tooth has slight wear facets on the tips of both cusps, but no wear on the saddle connecting them. These wear facets cut through a thin layer of enamel exposing dentine below. The tooth-bearing fragment described herein is likely from the posterior or middle of the maxilla or dentary, because as seen in BP / 1 / 5296 and SAM-PK- 6215, the teeth in Palacrodon maxillae and dentaries become increasingly cylindrical and peg-like towards the anterior end of the jaw and lose their mesiodistal contact. MNA V 11247 (Fig. 3 B) is an isolated tooth attached to a fragment of jaw. The tooth is 2.7 mm in mesiodistal length and 3.2 mm in labiolingual width, and 2.1 mm at its greatest apicobasal height. Remnant fragments of adjacent teeth can be seen fused to both the mesial and distal margins of this tooth and a small fragment of bone is attached to the base of the tooth on its labial or lingual side. Like the anteriormost tooth in MNA V 3684, this tooth is worn largely on the apex of both cusps exposing dentine, and the wear facets extend onto the saddle connecting the cusps creating a lemniscate shape.	en	Kligman, Ben T., Marsh, Adam D., Parker, William G. (2018): First records of diapsid Palacrodon from the Norian, Late Triassic Chinle Formation of Arizona, and their biogeographic implications. Acta Palaeontologica Polonica 63 (1): 117-127, DOI: 10.4202/app.00426.2017, URL: http://dx.doi.org/10.4202/app.00426.2017
