A late Maastrichtian selachian assemblage from the Peedee Formation of North Carolina, USA.

A diverse selachian fauna was collected from the Island Creek Member of the Peedee Formation at Castle Hayne, New Hanover County , North Carolina , USA . This inner neritic assemblage consists of 23 species from eight orders, 17 families, and 20 genera and includes the new species Ptychotrygon clementsi sp. nov. The dentition of a few large macrophagous species with large palaeobiogeographical ranges is described. However, the majority of the reported specimens belong to relatively small species that are endemic to the southern regions of the Western Interior Seaway and the Atlantic and Gulf Coastal plains of North America .


INTRODUCTION
The Atlantic and Gulf coastal plains of the United States have many Late Cretaceous and Palaeogene marine deposits that are rich in selachian (shark and ray) material (e.g., Ward and Wiest 1990;Kent 1994;Case 1981Case , 1994Parmley and Cicimurri 2003;Cicimurri 2007;Case et al. 2015). Herein, we describe an assemblage recovered from the late Maastrichtian Island Creek Member of the Peedee Formation at Castle Hayne, New Hanover County, North Carolina. Case (1979) previously described 11 euselachian taxa from this formation in Duplin County, North Carolina. The majority of the recovered species were rather large macrophagous sharks with relatively large palaeobiogeographical ranges; only two batoids were reported. In addition to presenting a new Ptychotrygon species, the purpose of this study is to augment the faunal list of selachians that are found in this particular geological unit and to elucidate palaeobiogeographical extensions.

GEOLOGY
All specimens were recovered from the late Maastrichtian Island Creek Member of the Peedee Formation. The Island Creek Member of the Peedee Formation was described by Dockal et al. (1998, p.158) as an "olive gray, well sorted, very fine to fine grained, poorly indurated, bioturbated, argillaceous, dolomitic quartz wacke". It is found in Brunswick, New Hanover, Pender and Onslow Counties in North Carolina and reaches a thickness of almost 15 meters (Dockal et al. 1998). At this locality the Island Creek Member rests on the Rocky Point Member of the Peedee Formation and is overlain by the late middle to early late Eocene Castle Hayne Formation. The Island Creek Member in the Martin-Marietta Castle Hayne Quarry has variable thickness and a tendency to pinch out over short distances. The quarry exposure where the bulk samples were collected has an exposed thickness of approximately 2 m. The upper few centimeters are heavily burrowed and infilled with material from the overlying Castle Hayne Formation. Selachian material is sparse in the lower 1.5 m of this exposure and more concentrated in the upper 0.4 m in an area between a discontinuous, mostly disarticulated layer of Exogyra shells and the base of the Castle Hayne Formation. The Island Creek Member represents an inner neritic environment of normal salinity (Dockal et al. 1998;Harris and Self-Trail 2006). An age of 66.9 Ma was reported, based on 87Sr/86Sr isotopic analysis performed on the cuticle of a well-preserved crab Ophthalmoplax brasiliana (Vega et al. 2013).
A late Maastrichtian selachian assemblage from the Peedee Formation of North Carolina, USA

METHODS AND MATERIALS
The dentition was recovered from a quarry exposure within the Martin-Marietta Aggregate, Castle Hayne Quarry (Fig. 1) located in New Hanover County,North Carolina (34º 22' 30" N,77º 50' 6" W). The majority of the specimens were collected by bulk sampling using a U.S. Standard Sieve Series No. 30 (530 microns/0.0234 in opening). Some of the larger teeth were surface collected from spoil piles within the quarry. Adhering matrix was removed using buffered 10% acetic acid solution. Smaller teeth were imaged using a Jeol Field Emission Scanning Electron Microscope (JSM-6301 FXV), whereas larger teeth were coating in ammonium chloride and imaged using a Nikon DXM 1200c digital camera mounted on a Zeiss Discovery V8 stereomicroscope. The material is catalogued in the collections of the University of Alberta Laboratory for Vertebrate Palaeontology (UALVP). Dental terminology and taxonomy largely follows that of Cappetta (2012).

Description:
The fractured upper anterior tooth with a relatively large distally inclined median cusp (= acrocone) is partially damaged. The mesial cutting edge bears three small distally inclined cusplets. The upper two-thirds of the distal cutting edge is more or less straight, whereas the basal one-third is concave. A smaller distally inclined cusp (= accessory cone) follows the median cusp. The labial and lingual faces of the poorly preserved root are high and bear a strong lingual protuberance. Both root faces bear multiple foramina.
The fractured lower lateral tooth is missing the median cusp but has preserved six distally inclined cusps of decreasing size. Both cusp cutting edges are very slightly convex.
The root is incomplete. The labial root face is flat, whereas the lingual face contains a well-developed budge. Both faces possess multiple foramina. Remarks: Cappetta (2012) noted that the lower lateral teeth of Notidanodon can reach up to 6 cm in width. The relatively small size of the teeth described herein indicates that they likely belonged to a juvenile individual. Late Cretaceous reports of Notidanodon include N. dentatus (Woodward, 1886), from New Zealand (Woodward 1886;Davis 1888), Antarctica (Martin and Crame 2006), and South America (Bogan et al. 2016), and N. pectinatus from Europe (Agassiz 1843;Woodward 1886), New Zealand (Adolfssen and Ward 2014), Antarctica (Cione and Medina 1987) and the west coast of North America (Applegate 1965). Adolfssen and Ward (2014) noted that the mesial cusplets are clearly separated and more erect in the latter species. The Peedee specimens have an overall morphology similar to that of N. dentatus; however, given the poor preservation, we conservatively leave this specimen in open nomenclature. It should be noted that it is the first occurrence of Notidanodon from the east coast of North America.
Order SQUALIFORMES Goodrich, 1909 Family SQUALIDAE Bonaparte, 1834 Genus Squalus Linnaeus, 1758 Squalus huntensis Case and Cappetta, 1997 Figure 2C Referred Material: UALVP 57017, complete tooth. Description: This is a small tooth with a median cusp that is strongly distally inclined. The basal one-third of the mesial cutting edge is convex, whereas the remaining apical two-thirds is more or less straight. The distal cutting edge is considerably smaller and is also relatively straight. The distal heel is high and well-developed. The labial crown face is smooth and has a narrow and elongated apron that extends well below the basal edge of the root. The lingual crown face is also smooth and bears a distinct uvula. The low root has a flat basal face and a large central foramen. Multiple smaller foramina are situated along the labial root face.

Remarks:
This species was first reported from the late Maastrichtian Kemp Formation of Texas (Case and Cappetta 1997). Teeth reported by Welton and Farish (1993) as Squalus sp. from the same formation is likely conspecific. The Peedee specimen represents only the occurrence of this species outside of Texas.

Description:
The anterior tooth has a median cusp that is flanked by two pairs of divergent lateral cusplets. Both crown faces are smooth but the enameloid of the apron is slightly damaged. The basal edge of the apron is straight and overhangs the root. The latter is considerably damaged but the remains indicate that the root lobes are V-shaped in basal view. The lateral tooth is mesodistally elongated. The crown is slightly convex and divided into labial and lingual faces by a transverse ridge. Both faces have enameloid folding that run perpendicular to this ridge. The crown overhangs the root. Both labial and lingual root faces possess large and smaller foramina. The basal face is more or less flat.

Remarks:
The Peedee specimens represent the second known occurrence of Heterodontus granti and the first report of a lateral tooth from this species. This taxon was erected based on anterior and anterolateral teeth from the late Maastrichtian Kemp Clay Formation of Texas (Case and Cappetta 1997).
Description: The anterolateral tooth has a tall median cusp that is flanked by a pair of poorly developed lateral cusplets. Distal to the lateral cusplets is a second incipient pair. The labial crown face has weak striations that extend to the apex but are more concentrated on the basal half of the median cusp. The apron overhangs the labial root face and has a medially positioned concavity. The lingual crown face is smooth and has a distinct medio-lingual protuberance. The root is low and slightly damaged. The root lobes are V-shaped in basal view and a large central foramen is present.

Remarks:
Cantioscyllium meyeri was first reported from late Maastrichtian Kemp Clay Formation of Texas (Case and Cappetta, 1997) and subsequently reported from the early Campanian Taylor Marl Formation (Cappetta and Case, 1999). Teeth of C. saginatus (Meyer, 1974) are likely conspecific with that of C. meyeri (Cappetta and Case, 1999). The overall morphology of the Peedee tooth is similar to the latter; however, the enameloid folding of the labial crown face is considerably weaker than that of the type material. As such, we conservatively noted that the specimen conforms favourably to C. meyeri.

Description:
The anterior teeth have a tall median cusp that is lingually directed. The cusp is distinctly separated from a pair of slightly divergent lateral cusplets. The upper region of the labial crown face bears strong labial crest. The relatively wide apron overhangs the labial root face and has a basal edge that is rounded or is concave medially. The lingual crown face is smooth and contains a well-developed medio-lingual protuberance. The root is poorly preserved but appears to have V-shaped root lobes and a large central foramen in basal view.

Remarks:
This species was first reported from the late Maastrichtian Kemp Clay Formation of Texas (Case and Cappetta 1997). Antunes and Cappetta (2002) reported teeth of similar morphology from the late Campanian/early Maastrichtian of Angola; however, they did note slight differences including smaller lateral cusplets, an apron that is wider and less prominent, and a less distinct labial crown crest than the type material.

Description:
The anterior tooth has a median cusp that is lingually directed and flanked by two pairs of slightly divergent lateral cusplets. The labial crown face bears labial crest that becomes braided at its base. The apron overhangs the labial root face and its basal edge is concave medially. The smooth lingual crown face has a well-developed medio-lingual protuberance. The root is considerably damaged but the central foramen is preserved.

Remarks: First reported from the late Maastrichtian
Kemp Clay Formation of Texas, Case and Cappetta (1997) distinguished this species from P. antiquum (Case and Cappetta, 1997) by its larger overall size, taller median cusp, multiple pairs of lateral cusplets, and its salient apron that has a basal edge that is more concave medially. These characters are clearly identified in the Peedee tooth. Becker et al. (2006) also reported this species from the late Maastrichtian Arkadelphia Formation of Arkansas.
Order LAMNIFORMES Berg, 1958Family MITSUKURINIDAE Jordan, 1898 Genus Anomotodon Arambourg, 1952 Anomotodon cf. A. toddi Case and Cappetta, 1997 Figure 3A Referred Material: UALVP 57024, complete lateral tooth. Description: This tooth has a tall triangular median cusp that is distally inclined and flanked by a pair of rounded distal heels. The slightly damaged labial crown face is mostly smooth with only a few very weak enameloid folds situated along the base medially. The labial basal edge overhangs the root. The lingual face is completely smooth and convex. A distinct cutting edge runs continuously across the cusp and cusplets. The root is somewhat eroded.
The lingual protuberance has a nutrient groove that bears foramina. A shallow U-shaped basal concavity separates the asymmetrical root lobes. The mesial lobe is elongated and rounded, whereas the distal lobe is more angular.

Remarks:
The lack of lingual enameloid folding distinguishes this species from other Anomotodon taxa (Case and Cappetta 1997). The only previous reports of A. toddi are from the Campanian (Welton and Farish 1993, as Paranomotodon sp.) and late Maastrichtian of Texas (Case and Cappetta 1997). Mustafa (2000) reported this species from the late Santonian of Jordan. The single recovered tooth also lacks any lingual striations; however, the crown heels appear less developed and the root is more gracile and possesses rounded root lobes. As such, the Jordanian (Mustafa 2000) specimens likely represent a separate but closely related species. We cautiously assign the Peedee specimen as Anomotodon cf. A. toddi because of the slightly eroded nature of the root.  Cappetta and Case, 1975 Figure 3B and C Referred Material: UALVP 57025, complete lower anterior tooth; UALVP 57026, complete upper lateral tooth.

Description:
The anterior tooth has a narrow and erect median cusp that is slightly lingually directed. The labial crown face is slightly convex and overhangs the labial root face. The lingual crown face is strongly convex. Both crown faces are completely devoid of any enameloid folding. A distinct cutting edge runs continuously across the cusp and a pair of well-developed lateral cusplets. A narrow lingual neck is present. The lingual protuberance bears a strong nutrient groove. A deep 'U-shaped' basal concavity separates the elongated root lobes.
The lateral tooth has a distally inclined median cusp that is flanked by a pair of small erect lateral cusplets. The smooth labial face slightly overhangs the root and is more or less flat, whereas the smooth lingual face is convex. The lingual neck is narrow. The lingual protuberance possesses a distinct nutrient groove and central foramen. The relatively shallow and V-shaped basal concavity separated the root lobes. Both root faces have additional foramina.
Remarks: Carcharias samhammeri was originally described from the early Maastrichtian of New Jersey (Cappetta and Case 1975). Subsequently, this species has also been reported from Western Interior Seaway late Maastrichtian deposits of South Dakota (Becker et al. 2004, as Carcharias cf. C. samhammeri) and Texas (Case and Cappetta 1997, as Carcharias cf. C. samhammeri). The single tooth described from the latter deposit closely resembles the lateral Peedee specimen. The gracile nature of both of these teeth, relatively to that of the type material, may be the result of ontogenetic variation (Case and Cappetta 1997).
Description: This tooth has an erect median cusp flanked by two pairs of large lateral cusplets. The labial crown face is flat and overhangs the root. Short enameloid folds are present along the base of the labial face. The lingual crown face is convex and bears distinct striation that extends over one-half of the height of the median cusp and lateral cusplets. The cutting edge is distinct and runs continuously across the cusp and cusplets. The lingual neck is narrow. The lingual protuberance is well-developed and contains two central foramina. The basal concavity is U-shaped and separated root lobes that are somewhat labiolingually compressed. Small foramina are present throughout both root faces.
Remarks: Odontaspis aculeatus was original described from the late Campanian of New Jersey (Cappetta and Case 1975) and subsequently reported from late Campanian to late Maastrichtian deposits of the Severn, Marshalltown and Mount Laurel formations of the Chesapeake Bay region (Lauginiger and Hartstein 1983;Hartstein et al. 1999;Kent 1994). From the Gulf coastal plain, this species was reported from the late Maastrichtian Arkadelphia Formation of Arkansas (Becker et al. 2006). Within the Western Interior Seaway, this species has been reported from the late Campanian Dinosaur Park Formation of Alberta (Beavan and Russell 1999), the late Maastrichtian Fox Hills Formation of South Dakota (Becker et al. 2004) and the late Maastrichtian Kemp Clay Formation of Texas (Case and Cappetta 1975).
Family OTODONTIDAE Glikman, 1964Genus Cretalamna Glikman, 1958Cretalamna maroccana (Arambourg, 1935 Figure 3E smooth labial crown face is more or less flat. The lingual face is also smooth but convex. A distinct cutting edge runs continuously across the median cusp and lateral cusplets. The lingual neck is narrow. The lingual protuberance bears two foramina. A shallow basal concavity separates rectangular-shaped root lobes.

Remarks:
This cosmopolitan species has been reported from northern and western Africa (e.g., Arambourg 1935Arambourg , 1952Dartevelle and Casier 1959;Antunes 1964;Cappetta et al. 2014), Madagascar (Gottfried et al. 2001) and the Middle East (Bardet et al. 2000). In North America, C. maroccana was reported from late Maastrichtian of Texas (Welton and Farish 1993: p.112, fig. 6, as Serratolamna serrata; Case and Cappetta 1997) and the Chesapeake Bay region (Kent 1994, as C. biauriculata maroccana). Teeth previously reported from the Peedee Formation of Duplin County, North Carolina by Case (1979) as C. biauriculata show an overall morphology more akin to that of C. marocanna.
Family ANACORACIDAE Casier, 1947Genus Squalicorax Whitley, 1939 Squalicorax kaupi (Agassiz, 1843) Figure 3F Referred Material: UALVP 57029, complete lateral tooth. Description: This tooth has a large distally inclined median cusp. The labial crown face is flat, whereas the lingual face is convex. The basal one-half of the mesial cutting edge is strongly convex, whereas the apical 2/3 is more-orless straight. The distal cutting edge is relatively straight and vertical. The distal heel forms an obtuse angle with the distal cutting edge. The cutting edges of the median cusp bear simple serrations that decrease in size towards the apex and crown base. The serrations run continuously over the distal heel. A lingual band is present but is somewhat eroded. The root is high with a weak lingual protuberance that lacks a nutrient groove. The root lobes are slightly asymmetrical with the distal lobe being slightly more robust. The basal concavity is shallow. Both the labial and lingual root faces contain various sized foramina.
Remarks: Squalicorax kaupi is a cosmopolitan taxon that has been reported from Coniacian to Maastrichtian deposit of Europe, the Middle East, and Africa (Cappetta 2012;Corral et al. 2016 and references therein). In North America, this species has been reported from the southern regions of the Western Interior Seaway (Welton and Farish 1993;Case and Cappetta 1997;Cappetta and Case 1999;Shimada and Cicimurri 2006) and the Gulf Coast Plain (Becker et al. 2006). This species was pre-viously reported from the Peedee Formation of Duplin County, North Carolina (Case 1979). In addition to the Peedee specimens described from this formation, Atlantic Coastal Plain reports of S. kaupi also include Campanian and Maastrichtian of New Jersey (e.g., Cappetta and Case 1975;Case et al. 2001).
It should be noted that in their description of Squalicorax cf. S. lindstromi (Davis, 1890) from the Santonian Hosta Tongue of the Point Lookout Sandstone of New Mexico, Bourdon et al (2011, p. 15) considered S. kaupi as being a "suite of similar taxa that have typically been lumped under a single name." Until a complete review of this species is undertaken, we conservatively assign the Peedee teeth to S. kaupi.
Squalicorax pristodontus (Agassiz, 1843) Figure 3G Referred Material: UALVP 57030, incomplete lateral tooth. Description: This is a large tooth with a distally inclined median cusp. The labial crown face is flat but has multiple shallow grooves medially above the crown-root boundary. The lingual crown face is convex and is considerably damaged basally. The basal one-half of the mesial cutting edge is strongly convex, whereas the apical 2/3 is more-or-less straight. The distal cutting edge is relatively straight and oblique. The distal heel is only slightly differentiated from the distal cutting edge. The irregular serrations run continuously over the median cusp and distal heel. The root is high with a weak lingual protuberance that bears a large nutrient foramen. The root lobes are damaged but appear to be asymmetrical. The labial root faces contain a number of large foramina medially. Both faces have additional smaller foramina.
Remarks: Squalicorax pristodontus has a widespread palaeobiogeographical distribution that includes Europe, the Middle East, Africa, and South America (Cappetta 2012;Cuny et al. 2012;Corral et al. 2016 and references therein). North American reports include the southern Western Interior Seaway (Welton and Farish 1993;Shimada and Cicimurri 2006) and New Jersey (Cappetta and Case 1975). A single tooth of S. pristodontus was also reported from the Peedee Formation of Duplin County, North Carolina (Case 1979). Teeth of the species can be differentiated from that of S. kaupi by having a less acute median cusp apex and less distinct distal heel, possessing more irregular serrations, having a higher root, and being larger in overall size (Welton and Farish 1993;Becker et al. 2006;Cappetta 2012;Corral et al 2016). These characters are readily apparently in the Peedee specimen.
Family PSEUDOCORACIDAE Cappetta, 2012 Genus Pseudocorax Priem, 1897 Pseudocorax cf. P. affinis (Münster in Agassiz, 1843) Figure 3H Referred Material: UALVP 57031, complete tooth. Description: This tooth has a distally inclined median cusp. The labial crown face is flat and slightly overhangs the labial root face. The lingual crown face is convex. The sigmoid mesial cutting edge bears irregular serrations that are poorly developed towards the apex and base. The distal cutting edge is convex and separated from a distal heel by a distinct notch. Well-developed serrations run continuously across the distal cutting edge and heel. The lingual protuberance has two large foramina and lacks a distinct nutrient groove. The asymmetrical root lobes are separated by a relatively deep basal concave.

Remarks: Pseudocorax affinis has been reported from
Campanian The overall tooth morphology of the Peedee specimen closely resembles that of P. affinis. However, we cautiously assign this tooth to Pseudocorax cf. P. affinis because it lacks a distinct nutrient groove that is characteristic of this species.
Description: This tooth is comprised of tall medial cusp that is distally inclined and flanked by two erect lateral cusplets medially and three divergent cusplets distally. The smooth labial crown face is more or less flat and has a sigmoid basal edge. The lingual face is smooth and convex. A distinct cutting edge runs continuously across the cusp and cusplets. The lingual protuberance has a distinct nutrient groove containing a large foramen. The labial root face has numerous small foramina and larger elongated foramina situated in the medial region. A shallow V-shaped basal concavity separates the asymmetrical root lobes. The rectangular-shaped distal lobe is considerably larger than that of the mesial root lobe.
Remarks: Serratolamna serrata is a widely distributed taxon that appears to be restricted to Maastrichtian deposits (Underwood and Mitchell, 2000). This species has been reported from Europe, the Middle East, northern and western Africa, Madagascar, and South America (e.g., Gottfried et al. 2001;Cappetta 2012;Corral et al. 2016 and references therein). From North American deposits, this species has been reported throughout the Western Interior Seaway (e.g., Welton and Farish 1993;Case and Cappetta 1997;Hoganson and Murphy 2002;Becker et al. 2004;Shimada and Brereton 2007) and the Gulf Coast Plain (Becker et al. 2006). Along the Atlantic Coastal Plain, S. serrata was reported from New Jersey (Case 1995;Case et al. 2001) and the Chesapeake Bay region (Kent 1994). Case (1979) previously reported its teeth from the Peedee Formation of Duplin County, North Carolina.
Order CARCHARHINIFORMES Compagno, 1973 Family TRIAKIDAE Gray, 1851Genus Palaeogaleus Gurr, 1962 Palaeogaleus sp. Figure 3J Referred Material: UALVP 57033, complete tooth. Description: This tooth has a triangular median cusp that is distally inclined. The mesial heel bears a single lateral cusplet, whereas the distal heel has two cusplets and flanked by a pair of rounded distal heels. The labial crown face overhangs the root and is mostly smooth with the exception of a few very weak enameloid folds situated under the distal-most lateral cusplet. The lingual crown face has strong enameloid folding along the basal region of the mesial and distal heels. The root is mesiodistally elongated. The nutrient groove completely divides the lingual protuberance and root lobes which have a flat basal face. A central foramen and margino-lingual foramina are present.  Becker et al. (2004) is also bears some resemblance to the Peedee tooth. However, unlike the dentition of these species, the tooth described herein possesses strong labial crown enameloid folding. In their report of P. havreensis Herman 1977 from the Campanian of England, Underwood and Ward (2008) noted that the presence of strong ornamentation in the teeth of this taxon likely represents upper dentition, whereas weak ornamentation likely represents lower jaw dentition.

Remarks:
Consequently, the difference in ornamentation of between the Peedee specimen and the other contemporaneous species may simply be due to dignathic hetereodonty. We therefore, conservatively leave this tooth in open nomenclature.
Description: This is a small tooth with a non-cuspidate and smooth crown. The labial crown edge is rounded and convex, whereas the lingual crown edge has an elongated median uvula that is flanked by a pair of less-developed lateral uvulae. The root is completely missing.

Remarks:
Given the poorly preserved nature of this tooth and the conservative nature of rhinobatoid tooth morphology (see Kriwet 1999;Kriwet et al. 2009;Cappetta 2012), we tentatively identify this specimen as Rhinobatos sp.
Description: These teeth have a crown that contains a tall lingually-directed median cusp. The crown faces are smooth and separated by distinct transverse edge. The apron overhangs the labial root face and has a medially positioned convex protuberance. The lingual crown face has a distinct medio-lingual protuberance. The root is constricted below the crown-root boundary. The root lobes are mesiodistally expanded and separated by a well-developed nutrient groove.
Remarks: Case and Cappetta (1997) first described Raja farishi from the late Maastrichtian Kemp Clay Formation of Texas and can be differentiated from other Raja species by a crown with a more lingually directed cusp, well-developed transverse edge separating the faces, the lack of a transverse crest, and more separated uvula. The root is also higher, is constricted just below the crown-root boundary, and has mesodistally wider root lobes (Case and Cappetta, 1997;Becker et al. 2004). These characters are clearly apparent in the Peedee specimen. This species is restricted to late Maastrichtian of North America and has been previously reported from the Kemp Clay Formation of Texas, Arkadelphia Formation of Arkansas (Becker et al. 2004), and Severn Formation of Maryland (Hartstein et al. 1999).
Description: This is a rostal tooth with a relatively short crown (= cap) that is dorsoventrally compressed towards the apex and is somewhat posteriorly directed. The anterior margin is the convex, whereas the posterior margin is more or less straight. Distinct cutting edges are restricted to the apical half of the crown. The enameloid has considerable damage along the base of the crown but there appears to be a number of short ridges in the undamaged region. The basal region of the large root (= peduncle) is expanded dorsoventrally and forms two short lobes that have a flat basal face.
Description: This is a rostal spine with a relatively large crown that is slightly dorsoventrally compressed and completely smooth. The anterior margin is more or less straight, whereas the posterior margin is sigmoid. Distinct cutting edges extend from the apex to the base of the crown. The root is large and slightly damaged. The basal region is expanded dorsoventrally and forms two short lobes.
Genus Sclerorhynchus Woodward, 1889 Sclerorhynchus cf. S. pettersi Case and Cappetta, 1997 Figure 4E Referred Material: UALVP 57038, incomplete rostral spine. Description: This rostal spine has a large smooth crown that is dorsoventrally compressed except at the basal bulge. The anterior margin of the crown is convex and bears a distinct cutting edge that extends from the apex to the base. The convex posterior margin also has a distinct cutting edge that extends from the apex to a well-developed barb.
Most of the root is missing.
Remarks: Sclerorhynchus pettersi was first described from the late Maastrichtian of Texas by Case and Cappetta (1997). Subsequently, the species has been reported from the late Maastrichtian New Egypt Formation of New Jersey and Severn Formation of Maryland (Hartstein et al. 1999). Becker et al. (2004) and Becker et al. (2006) reported late Maastrichtian rostral spines identified as Sclerorhynchus sp. from the Fox Hills Formation of South Dakota and Arkadelphia Formation of Arkansas, respectively, and noted their morphological resemblance to S. pettersi.
Family PTYCHOTRYGONIDAE Kriwet, Nunn, andKlug, 2009 Genus Ptychotrygon Jaekel, 1894 Ptychotrygon clementsi sp. nov. Figure  Remarks: Kriwet et al. (2009) noted that the ptychotrygonids can be distinguished from other sclerorhynchiforms by the presence of a transverse crest and a distinct labial visor. Ptychotrygon is a rather speciose taxon that has been reported from Albian -Maastrichtian deposits of Europe, northern Africa, and North America (Kriwet et al. 2009;Cappetta 2012). North American Campanian and Maastrichtian species include P. blainensis Case, 1978 from the Judith River Formation of Montana, P. boothi Case, 1987, P. ellae Case, 1987and P. greybullensis Case, 1987 from the Mesaverde Formation of Wyoming, P. vermiculata Cappetta, 1975b from the Mount Laurel Formation of New Jersey, and P. winni Case and Cappetta, 1997 and P. texana (Leriche, 1940)   Remarks: Case and Cappetta (1997)   Description: This tooth has a robust crown that is rhombic in occlusal view. In profile view, the flat occlusal surface is somewhat inclined lingually. The margino-labial and margino-lingual faces are slightly concave and bear distinct vertical enameloid folding. A weak lingual bulge is present. The root is positioned under the lingual region of the crown. The root lobes are divided by a well-developed nutrient groove containing several nutrient foramina.

Remarks:
Rhombodus binkhorsti is a wide ranging species that has been reported from Maastrichtian deposits of Europe, northern and western Africa, and South America (Cappetta 2012;Corral et al. 2016 and references therein). North American reports include Western Interior Seaway (Welton and Farish 1993;Case and Cappetta 1997) and the Atlantic and Gulf Coastal plains (Case et al. 2001;Becker et al. 2006). This species was previously reported from the Peedee Formation of Duplin County, North Carolina by Case (1979, as Rhombodus cf. R. binkhorsti).

DISCUSSION
This inner neritic assemblage described herein includes 23 species from 20 genera, 17 families and eight orders of selachians, with the description of the new species Ptychotrygon clementsi sp. nov. Additionally, Case (1979) reported Hybodus sp., Scapanorhynchus texanus (Roemer, 1849), and Archaeolamna kopingensis (Davis, 1890) from the Pee Dee Formation, exposed in Duplin County, North Carolina. It should be noted that the tooth figured as Odontaspis sp. by Case (1979: figs. 13 and 14) bears a strong resemblance to that of Carcharias samhammeri.
Species (and those that compare favourably) from the Peedee assemblage that appear endemic to the southern Western Interior Seaway (e.g., Welton and Farish 1993;Case and Cappetta 1997), Gulf Coastal (e.g., Becker et al. 2006) and Atlantic Coastal plains (e.g., Cappetta and Case 1975;Case 1979;Kent 1994) include Squalus huntensis, Heterdontus granti, Cantioscyllium meyeri, Plicatoscyllium derameei, Raja farishi, Dasyatis commercensis and the new species Ptychotrygon clementsi. Those species that have an expanded distribution into the northern regions of the Western Interior Seaway (e.g., Beavan and Russell 1999;Becker et al. 2004;Cook et al. 2014) include Carcharias samhammeri, Odontaspis aculeatus, Ischyrhiza avonicola, I. mira, and Sclerorhynchus pettersi. The morphology of the recovered Palaeogaleus tooth is somewhat different from that of European species and it may represent an endemic taxon of North America. Further supporting this notion is the rather limited palaeobiogeographic range of the congeneric taxa (see Cappetta 2012). Cosmopolitan species from the Peedee assemblage that have been reported from deposits outside of North America include Notidanodon sp., Cretalamna maroccana, Squlicorax kaupi, Squlicorax pristodontus, Pseudocorax affinis, Serratolamna serrata, and Rhombodus binkhorsti. As mentioned previously, the recovered Notidanodon teeth are heavily damaged but do resemble that of the widely distributed species Notidanodon dentatus. Also noted above was the questionable occurrence of Plicatoscyllium antiquum from Angola (Antunes and Cappetta 2002). Despite being demersal, many extant ginglymostomatid species have rather wide biogeographical ranges (Musick et al. 2004). The occurrence of the late Maastrichtian species P. lehneri (Leriche, 1938) from multiple deposits on both sides of the Atlantic seems to corroborate this notion (Corral et al. 2016). Therefore, it is plausible that P. antiquum frequented both western African and southeastern North American waters. The report of Anomotodon toddi from the late Santonian of Jordan (Mustafa 2000) is also suspect given subtle differences in tooth morphology and likely represents a new species. The limited distribution of Palaeogene species [e.g., A. sheppeyensis (Casier, 1966), A. novus (Winkler, 1876), and A. cravenensis (Case, 1980)] appears to support the opinion herein that A. toddi was endemic to North American waters. The occurrence of Squalicorax, Cretalamna, and Serratolamna in the Peedee assemblage is not surprising as Corral et al. (2016: p. 658) noted that these pelagic taxa migrated across the Proto-Atlantic "favoured by ocean currents, according to their global distribution". They also note that the benthic Rhombodus binkhorsti may have attained its circumtropical distribution by means of "transoceanic migration by swimming along the shelf from western Africa to South America." A northern expansion of this species from South America into the southern region of the Western Interior Seaway and the Atlantic and Gulf Coastal plains is not unlikely. Finally, the occurrence of Hybodus, Scapanorhynchus texanus, and Archaeolamna kopingensis from the Peedee Formation exposed in Duplin County, North Carolina are also reported from continents outside of North America (e.g., Biddle 1993;Siverson 1992;Mustafa 2000;Zalmout and Mustafa 2001;Antunes and Cappetta 2002;Cappetta 2012;Guinot et al 2013;Vullo and Courville 2014).