Compagno (1984) includes a single extant species in the genus, Galeorhinus galeus (LINNAEUS, 1758). This is a moderately large (1.9 m) coastal-pelagic species of temperate continental and insular waters, ranging from bays to well out to sea (2 - 471 m). It is not present in the waters of the Western North Atlantic, but can be found in the South Atlantic and Eastern North Atlantic, Eastern Pacific and Australia. An opportunistic predator, it feeds on bony fish, cephalopods and miscellaneous invertebrates.
The dentition of this genus serves a clutching-cutting function and displays monognathic heterodonty. The crowns of these small teeth are compressed, triangular, and cuspidate distally, there are numerous cusplets. In most tooth positions, the cusp is distally directed and the mesial cutting edge is convex, however, in anterior positions the cusp is rather upright and the mesial cutting may be straight or weakly concave. The labial face of the crown overhangs the root with a pronounced bulge. The root itself is broad, rather thin and flat, with a distinct nutrient groove.
Cappetta (1987:115) indicated the genus extends back to the Lower Turonian (Upper Cretaceous) and has been reported from Europe, Africa and North America. Some of the fossil species he included were:
Galeorhinus cuvieri (AGASSIZ 1835) Lower Eocene of Italy
(from well preserved skeletons),
G. girardoti HERMAN 1977 Campanian and Maastrichtian
G. lefevrei (DAIMERIES 1891) Ypresian-Lutetian of Europe,
G. minor (AGASSIZ 1843) Eocene of Europe and Morocco,
G. minutissimus AARAMBOURG, 1952 Ypresian of Morocco, and
G. ypresiensis CASIER 1946 Ypresian (Lower Eocene) Belgium.
Noubhani & Cappetta (1997:80) added G. mesetaensis (Thanetian) to the Late Palaeocene fauna of Morocco.
The North American fauna includes varying reports:
Jordan & Beal (1913) described G. hannibaldi from Miocene and Pliocene sediments of Southern California.
Case (1980: 91) reported G. affinis (PROBST 1878) from the Trent Fm (Oligocene, NC).
Ward & Wiest (1990) included G. ypresiensis in the Eocene of Maryland and Virginia.
Welton & Farish (1993:127) reported Galeorhinus sp teeth from Late Campanian - Maastrichtian exposures of Texas
Kent (1994: 76) included three species as present in the Chesapeake Bay region: G. girardoti (Severn Fm, Late Cretaceous), G. lefevrei (Aquia, Seleandian & Nanjemoy, Ypresian), and G. ypresiensis in Nanjemoy Fm.
Case & Cappeta (1997) included G. aff girardoti from the Kemp Clay of Texas.
Hartsein et al (1999: 18) included G. cf girardoti from the Severen (Maastrichtian) fauna of MD.
Müller (1999: 44-46) reported G. minor and G. lefevrei from the Piney Pt Fm (Luetian) of VA and G. aff galeus from the Old Church (Oligocene) of VA and St Marys Fm (Upper Miocene) of MD.
Kent (1999: 23-24) included G. ypresiensis in Nanjemoy (Ypresian) fauna of VA.
Case & Borodin (2000:26) attributed Lutetian teeth from the Castle Hayne Fm to G. cf galeus.
Purdy et al (2001: 139-40) ascribed Lee Creek teeth to G. cf affinis (PROBST, 1878) and include them in Pungo (units 1-5) and Yorktown (unit 1,?redeposit) sediments. Teeth of G. aff galeus have also been found in, but not formally reported from, the Oligocene of South Carolina (Chandler Bridge Formation).
Becker et al (2004:786) included G. cf girardoti from the Maastrichtian of South Dakota.
Cretaceous of Maryland & North Carolina
The accompanying specimens (Figs. - ) conform well with the Galeorhinus tooth-design. The North Carolina specimens are reworked Late Cretaceous; most likely Maastrichtian (Peedee Fm) in origin. These teeth reflect the typical Galeorhinus-design: distally-directed cusp, strong distal serrations and a lower labial base which strongly overhangs the root. The illustrated Severn tooth varies from the NC examples by bearing basal ridges, this may or may not of any diagnostic relevance.
Being Late Cretaceous in origin, North American teeth of this design are usually referred to as G. cf girardoti. These teeth do not conform to one particular aspect of Herman's (1977) description, "The crown is strongly labio-lingually compressed." (DeSchutter trans. 2007); but, are markedly thick -- they will be included as G. aff girardoti.
Aquia Formation Palaeocene of Maryland
Studies of Piscataway sediments of the Aquia Formation (Thanetian) have yielded two Galeorhinus-type tooth designs. Noubhani (pers. comm. 05-30-02) notes that the first (Fig. ), and less common, compares quite well with Morocco's G. minutissimus (Ypresian species). The second (Fig. ) and more common design shows similarities with the Moroccan Thanetian species G. mesetaensis. Without additional specimens, it would be premature to ascribe these specimens to a particular species. It is likely that a single species is present in the fauna.
The Cenozoic record of the east coast is certainly not lacking in opinions for the identification of tope shark teeth. Any firm determinations require not only reasonably complete dentition-sets of the new world material, but reliable reference-sets for the previously-named old world taxa. I will follow a less than scholarly approach referring the Eocene material as aff ypresiensis, and Neogene as aff galeus.
This election should not be confused with Case & Borodin's (2000) similar decision with Lutetian material from North Carolina. Two of the specimens they figure (58 & 59) have a serrate mesial cutting edge which they refer to as vestigial (not present in galeus). They go on to note that, "No ornamentation is present"; this likely refers to the folds of the lower labial face often seen in triakids. The specimens included herein (Fig & , as aff ypresiensis from a similar location and horizon) better compare with the Galeorhinus-design, a smooth cutting edge and the typical triakid folds.
A Lee Creek Fauna page on Galeorhinus sp from Heim on Sharks
Some thoughts by Leonard Compagno on Galeorhinus
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