North American reports of the Scapanorhynchus tooth-design start with Morton (1834: 31, pl. 11, fig 2 and possibly 3 & 11); Manning (pers. com. 2008) notes that "From the text (p. 31), it's unclear if two of these teeth (2 & 3) are from New Jersey, Alabama, or South Carolina, but one (fig. 11) is definitely from N.J." (Ref. accompanying fig -L.) This tooth-design was 'described' by Roemer (1849: 52, pl 1 Fig 7) as Lamna texana (Late Cretaceous, TX, accompanying fig. -cR). Other early reports include Gibbes (1849: pl 26, fig 119) Lamna contortidens AGASSIZ 1833 (=Scapanorhynchus LA1, Cretaceous of NM, accompanying fig. -cL) and Emmons (1856: 239, figs 70-71) Lamna elegans AGASSIZ 1833 (=cf texanus, "Miocene" marls of NC, fig. -R). The first usage of Woodward's generic name appears to have been Williston (1900).⁷. Although White (1956: 124) used S. texanus when commenting on some of Woodward's (1889) Alabama determinations, Miller (1967:223) attributed Black Creek (NC) teeth to Carcharias? sp & Isurus sp.

East Coast. The watershed moment appears to be Cappetta & Case (1975); they attributed these abundant⁸ NJ Upper Campanian teeth to Scapanorhynchus texanus and provided an excellent series of images (pl 1 13-16, pl 2 fig 1-36) and noted (trans.) "This species most probably derives from S. "raphiodon". Those authors go on to make particular note of the lingual 'tuberculés' (ridges) below the base of the crown. Following their paper, S. texanus has been reported along the East Coast by: Case (1979: 80-81) Peedee Fm.(Late Maastrichtian) NC, Schwimmer (1986: 114) Blufftown Fm (Campanian), western GA and Robb (1992: 79-80) Black Creek Fm. (Campanian), NC. Interestingly, Hartstein et al (1999) did not recover examples from the Severn Fm (Late Maastrichtian) of MD. [It must be noted that texanus teeth from the northern range (NJ) have never been compared & contrasted on a dentition-design basis with those from the southern (NC/GA).]

Interior Sea. Gibbes' (1849) "Lamna contortidens" (see above) appears to be the earliest report from the Interior Sea. These western sediments often include much older horizons than seen on the East Coast and specimens are attributed to Scapanorhynchus "raphiodon". Lacking a good literature collection for this region, I'm unsure whether these lower Late Cretaceous "raphiodon" teeth have ever been fully described and/or contrasted with texanus. More recent reports include: Stewart (1990: 21) S. raphiodon Green Horn Ls, Carlile Sh, & Smoky Hill Chalk (Turonian-Santonian), KS; Shimada (1996: 6) S. sp., Ft Hays Ls, Niobrara Chalk (lwr/mid Coniacian), KS; and Hamm & Shimada (2002) S raphiodon (5 assoc. teeth) Niobrara Fm, (?Santonian), KS. Further south, Becker et al. (2006) did not report the genus from the Arkadelphia Fm. (Late Maastrichtian), AR, but Manning & Dockery (1992:28-29) reported S. raphiodon texanus from the Frankstown Sand, Demopolid Fm (Late Campanian / Early Maastrichtian), MS.

Texas provides an excellent Cretaceous marine fossil record which has been studied extensively over the years. Manning (pers. com 2008) notes that the earliest published occurrence of Scapanorhynchus in NA is S. raphiodon, "Middle Cenomanian (uppermost Woodbine Grp, Lillian, Texas"; citing Meyer (1974: 231-2). Welton & Farish (1993: 94-95) include S. "raphiodon" as represented in Turonian-Coniacian sediments and S. texanus from the Campanian-Maastrichtian. There should be no one with a better 'feel' for NA Scapanorhynchus tooth-designs than Gerry Case; the complexity of this issue is best illustrated by two papers penned by him and Cappetta. Case & Cappetta (1997: 142) include as S. sp. small teeth from the Kemp Clay (Late Maastrichtian) TX (pl 3.9, 4.1-3). Their plate 4 figures 1 and 2 certainly appear to reflect Scapanorhynchus and do not compare well with texanus as 'defined' in Cappetta & Case (1975). Moving on, Cappetta & Case (1999: 19-21) included in the Texas fauna: S. texanus (Campanian) [no illustrations, these probably corresponded with their 1975 paper], S. cf "raphiodon" (pl. 11.5-11, captioned as S. sp in the plates) Turonian-Conacian (compare well with the Welton & Farish examples but less well with those in Herman 1977, plate VII), S. aff praeraphiodon SOKOLOV 1978 (pl. 11.1-3) Upper Cenomanian and S. sp. (pl. 11.8) Lower Campanian.

Dentition-design

Based solely on tooth-design (awl-like anteriors and rather broad-bladed laterals) Late Cretaceous Scapanorhynchus teeth appear to have had functionality similar to the extant Shortfin mako; a cutting / clutching dentition optimized for larger teleosts. This is much different than the extant goblin shark (Fig. ) with it's awl-like laterals. The actual tooth formula is less clear.

Relying on Arambourg (1952, pl II & III), captions, he deemed S. rapax to have three upper anteriors and the lower anteriors to be represented by a parasymphyseal (A0) and two anteriors. However, based on lateral profile, one of his figured UA3's (pl II, fig 3) is clearly a lower tooth not represented by his LA1 & LA2 figures. The resulting tooth-formula (Fig. ) would represent 3 upper and 4 lower anteriors as seen in the extant taxon.

Cappetta & Case (1975) provided a good set of S. texanus images, but other than the A1 positions, they figured no lateral profiles in association with other perspectives; their captions (and text) made no positional assignments other than anterior vs lateral. The tooth they proposed as the parasymphyseal (aka A0; pl 2, fig. 7) was only a lateral profile which was not lingually directed (more likely an upper tooth). Another figure (pl 2, fig 30) was only imaged laterally but could have been an A0. Based on root-design, another tooth (pl 2, fig 23) did not compare well with other upper laterals (?Serratolamna serrata) and was excluded from consideration. The resulting arrangement (Fig. ) better defines the lateral hollow than Arambourg's images, but is less definitive with the anterior hollows.

Herman (1977) provided another group of excellent multi-perspective images, in this case, S. raphiodon. The positions represented are less than the other authors, but they clearly depict three 'significant' lower anteriors (ref. Fig. ).

Cappetta (1980) studied and reported on the skeleton of Davis' S. lewisii from the Late Santonian of Lebanon. He determined:

Tooth-Design

The Late Cretaceous representative of the genus in the Mid-Atlantic States, S. texanus is characterized by strongly striated awl-like anterior teeth and usually distinctive laterals (see illustration). The anteriors can be broadly described as having slender and elongated bilobate roots that have a lingual protuberance with a short but deep groove. The crowns are long and narrow with distinct striations; lateral cusplets may be present based on position. The lateral teeth have broader roots, and the crowns can be nearly smooth or have weak (lingual) striations, and bear one or more lateral cusplets. The neck of anterior and upper teeth bear closely spaced lateral ridges which appear to merge near the base of the crown, joining to form the strong lingual striations (when present).

Anteriors. The first anterior position is relatively erect, lacks cusplets and has a mesio-distally compressed root. The second anterior is more distally inclined, may or may not have small pair of single cusplets and has more splayed roots. In the third position the cusp is shorter, distally inclined but may be mesially recurved, single cusplets are more common and the root lobes more greatly splayed. In each position, the lower tooth tends to be more lingually directed than its upper counterpart; the latter's cusp tends to be sigmoidal in profile.

Laterals. The laterals tend to have moderately-broad and smooth lingual crown faces although they may bear striations particularly laterally. Cusplet pairs (larger medial, smaller lateral) are present and the root is much more robust than seen in extant goblins. Upper teeth are more distally inclined and labially curved than their lower counterparts that are more erect. There appears to be propensity for the uppers to become progressively more inclined distally. Lower teeth remain quite erect, but become shorter distally.

Contrasting the dentition-design of Scapanorhynchus texanus with that of Mitsukurina owstoni, the greatest difference can be seen in the upper laterals in which the former's cutting-design (broad and cuspleted crowns) are simply narrow grasping-like teeth in the latter.

In Texas and the Interior Sea, a second goblin shark species occurs - S. "raphiodon" (AGGASIZ 1844) (Turonian-Coniacian). Welton & Farish (1993: 94-95) note that teeth from this species tend to be smaller, have narrower crowns and weaker striations. Shawn Hamm was fortunate enough recover a small set from the lower chalk (Late Coniacian). The teeth are certainly more delicate, but the striations are by no way weak.

Concluding thoughts

160-years after Roemer's texanus description there are many uncertainties remaining with these teeth. The NC specimens appear to map quite well with those of NJ, but I know of no positional reconstruction from near the type locale in Texas. This is only relevant because there are several NC specimens that require a large shoehorn to fit them into that dentition-design; is there a second species present?

S. 'raphiodon' is even more problematic. Is the name invalid as suggested by Siverson; and if valid, do the NA teeth equate with those from the English Chalk? Could they just reflect a chrono-variation of texanus? With the abundance of these teeth in many locations, dentition-reconstruction might provide some answers.