The wedgefishes are medium-sized (3m) coastal (shallow waters to 50m) bottom dwelling batoids normally inhabiting tropical waters of the Eastern Atlantic, Indian Ocean and Western Pacific. They are known (FishBase June 2008) to feed on crustaceans, mollusks, squid and small fishes. They currently recognize four species:
Rhynchobatus luebberti EHRENBAUM, 1915 - African wedgefish (Eastern So. Atlantic);
Rhynchobatus djiddensis (FORSSKÅL, 1775) - Giant guitarfish (Indian Ocean);
Rhynchobatus australiae WHITLEY, 1939 - Whitespotted wedgefish (Western Pacific);
Rhynchobatus laevis (BLOCH & SCHNEIDER, 1801) - Smooth nose wedgefish (NW Pacific).
I include these details because until seeing this FishBase list, I and others have been attributing wedgefish dentitions from the Philippines & Australia to R. djiddensis, while R. australiae may be the more appropriate identification. While attempting to clarify this matter, they will be included as R. "djiddensis".
The dentition is crushing in design with numerous (30+ per quadrate) small (to 5 mm) pavement teeth (larger mesially). The crowns are somewhat globular and when unworn, have a distinct transverse crest. The lingual face is flat to weakly concave on each side, separated by a moderate medial uvula; the labial face is weakly pitted. The roots project lingually with a well defined medial groove and central pore(s). The lingual root faces are strongly notched and include a distinct foramen. For a more detailed description of a Rhynchobatus "djiddensis" dentition see extant Rhynchobatus.
The Fossil Record
Cappetta (1987: 134) noted this genus could be tracked back to the Ypresian (Senegal) and reported them (at the time) as known from Europe, Africa and Japan; he rejected Arambourg's (1952d) report of Rhynchobatus from the Maastrichtian of Morocco. R. pristinus (PROBST 1877a) is the lower Miocene taxon from Europe. The highly regionalized distribution of extant taxa (as suggested above) might serve as a warning about readily equating North American material with similarly-aged European taxon.
The US record includes:
Case (1980:93, pl 9.3) reported as R. pristinus and Rhynchobatus sp specimens from the Trent Fm. (Oligocene) of North Carolina.
Bob Purdy (pers com 1996) of the Smithsonian identified Lower Pungo River teeth as Rhynchobatus sp noting that it was the only rhinobatoid genus positively identified as from Lee Creek.
Müller (1999: 55) included:
R. pristinus from the Old Church Fm, VA & Belgrade Fm., NC (both Oligocene);
Rhynchobatus sp 1 from the Piney Point Fm. (Middle Eocene), VA; and
Rhynchobatus sp 2 from the Pungo River Fm (Miocene), NC.
Purdy et al (2001: 89, Fig 7c-e) included small (to 2 mm) guitarfish teeth form the Upper Pungo River Fm (Middle Miocene) as Rhinobatos sp. It is impossible to judge the validity of this determination based on the description or figures. It is curious that Purdy recognized Rhynchobatus above but not in their paper.
Arambourg. C., 1952. Les Vértebrés Fossiles des Gisements de Phoshates (Maroc-Algérie-Tunisie). Notes et Mémoires du Division of Mines and Geology, French Morocco 92, 1-372.
Cappetta, H., 1987. Chondrichthyes II: Mesozoic and Cenozoic Elasmobranchii. Handbook of Paleoichthyology, 3B. Gustav Fischer Verlag, Stuttgart and New York, 193 pp.
Case, G., 1980. A Selachian Fauna from the Trent Formation, Lower Miocene of Eastern North Carolina In: Palaeontographica, 171:75-103
Froese, R. & Pauly, D. Editors. 2003. FishBase. World Wide Web electronic publication. www.FishBase.org, version April 2008.
Müller, A. 1999. Ichthyofaunen aus dem atlantischen Tertiär der USA. Leipziger Geowissenschafteb, Leipzig, 9/10: 1-360.
Müller, J., and. Henle, F., 1837. Gattungen der Haifische und Rochen nach einer von ihm mit Hrn. Henle unternommenen gemeinschaftlichen Arbeit über die Naturgeschichte der Knorpelfische. Bericht Akademie der Wissenschaften zu Berlin 1837: 111-118.
Probst, J., 1877. Beitrage zur Kenntnis der fossilen Fische aus der Molasse von Baltringen. Jh. Ver. vaterl. Naturkde., 33:69-103.
Pury, R., Schneider, V., Appelgate, S., McLellan, J., Meyer, R. & Slaughter, R., 2001. The Neogene Sharks, Rays, and Bony Fishes from Lee Creek Mine, Aurora, North Carolina. In: Geology and Paleontology of the Lee Creek Mine, North Carolina, III. C. E. Ray & D. J. Bohaska eds. Smithsonian Contributions to Paleobiology, No 90. Smithsonian Institution Press, Washington D.C. pp. 71-202.