This genus was erected by Case & Cappetta (1997: 137) for teeth that had previously been included in Ginglymostoma. Noubhani & Cappetta (1997: 42) included three species as present in Morocco's Maastrichtian fauna -- the new species Plicatoscyllium gharbii & P. youssoufiaense and P. minutum (FORIR, 1887). The authors went on to speculate that G. globidens CAPPETTA & CASE 1975 [Mt Laurel Sands, Upper Campanian, New Jersey], might also belong in this genus.
The teeth attributed to P. minutum not only included Forir's Hybodus minutus, but also synonymized were Ginglymostoma lehneri LERICHE 1838 and G. rugosum DARTEVILLE & CASIER, 1943. Plicatoscyllium minutum would have been widely distributed in the Maastrichtian of western Africa, Europe, eastern North America, the West Indies and the Late Campanian-Maastrichtian of Texas.
There are few reports of Plicatoscyllium from Eastern North America, and they are generally limited to those attributed to Ginglymostoma lehneri and the possible G. globidens.
Welton & Farish (1993: 83) included G. lehneri as a common component of the Campanian-Maastrichtian of Texas.
Kent (1994: 35) noted the presence of G. lehneri from the Severn Fm and G. globidens from the Marshalltown & Severn Fms (NJ & MD).
Cappetta & Case 1997 described P. antiquum and P. derameei (=W&F1993's G, lehneri) from the Maastrichtian of Texas. Nothing in their description explains why antiquum is not an ontogenetic variation of derameei or clearly differentiates the two from P. minutum.
Hartstein et al, (1999: 18) reported P. antiquum & P. derameei from the Severn Fm of Maryland.
The teeth of Plicatoscyllium minutum have a rather high cusp with one to four pairs of relatively high lateral cusplets. In anterior and lateral files, these cusplets are broad, pointed and well defined, but begin to disappear in more lateral positions. The labial crown face is characterized by a triangular zone of strong, baso-apically oriented, enameloid ridges which approach but do not reach the cusplets and apron. In more lateral positions, these ridges get smaller and more tightly spaced. The smooth apron is short & broad, and may bear a weak medial notch (weakly bifid).Viewed basally, the labially flaring lobes create a depression which grows shallower and narrower lingually and terminates at a broad central foramen. The root is rather high and globular lingually. A medio-lingual foramen is present on the root face as are a pair of margino-lingual foramina.
The need for Plicatoscyllium as a distinct genus from Ginglymostoma (generic splitting) is questionable but will (for now) be accepted (if not fully embraced) by the website. Synonymizing P. minutum and lehneri (specific lumping) seems more reasonable and will also be followed by the website. Erecting a new species (P. antiquum) for a western Atlantic form (regional splitting) of what appears to be P. minutum is less logical. Lacking a well argued reason for this decision the website will continue to include this tooth-design as P. minutum. One specimen (Fig. ) lacks the plicated labial face often associated with P. minutum and may represent another taxon.
Cappetta, H. and Case, G., 1975. Contribution ŕ l'étude des sélaciens du groupe Monmouth (Campanien - Maestrichtian) du New Jersey. Palaeontographica Abteilung A, 151:1-46.
Case, G. R., and H. Cappetta. 1997. A new selachian fauna from the late Maastrichtian of Texas. Muünchener Geowissenschaften Abhandungen 34:131-189.
Hartstein, E., Decina, L. and Keil, R., 1999. A Late Cretaceous (Severn Formation) Vertebrate Assemblage from Bowie, Maryland. The Mosasaur, Vol 6, Delaware Valley Paleontological Society. pp 17-23.
Kent, B., 1994. Fossil Sharks of the Chesapeake Region. Egan Rees & Boyer, Maryland. 146 pp
Noubhani, A and Cappetta, H., 1997. Les Orectolobiformes, Carcharhiniformes et Myliobatiformes des Bassins ŕ phosphate du Moroc (Maastrichtien-Lutétien basal)., PalaeoIchthyologica 8, München. 327 pp.
Welton, B. and Farish, R., 1993. The Collector's Guide to Fossil Sharks and Rays from the Cretaceous of Texas. Before Time, Texas. 204 pp.