The dasyatids are coastal rays, frequenting shallow waters (including estuaries and freshwater rivers) and preferring sub-tropical and tropical temperatures. The stingrays bear thorns, and are best characterized by their rhombic-shape, whip-like tails and caudal stinging spine. (See: Extant Whiptail Rays.)
Although the teeth of this family are quite distinctive, it is uncertain how much confidence can be placed in identifications (based solely on teeth) to the genus level. For all practical purposes, most fossil teeth have been ascribed to the "paleontological" genus "Dasyatis" which is not necessarily equivalent to its extant counterpart. The genus Dasyatis likely has a long history. Cappetta (1987: 163) notes that Lower Eocene skeletons (D. muricatat VOLTA 1796) from Italy have no notable differences when compared with extant specimens. He goes on to note first appearances as: the Americas - Cretaceous, Africa - Paleocene and Europe - Eocene.
Usually based on isolated teeth, numerous species have been described over the years. Some of those included by Cappetta are:
Dasyatis africana (DARTEVELLE & CASIER 1959) Paleocene, Africa;
D. branisai CAPPETTA 1975 Upper Cretaceous, So America;
D. davisi (CASIER 1966) Lower Eocene, England;
D. hexagonalis ARAMBOURG 1952 Paleocene, Morocco;
D. jaekeli (LERICHE 1905) Lower Eocene, Belgium;
D. probsti CAPPETTA 1970 Lower Miocene, France;
D. rugosa (PROBST 1877) Lower Miocene, Europe;
D. serralheiroi CAPPETTA 1970 Middle Miocene, Europe and
D. tricuspidatus CASIER 1946 Lower Eocene, Belgium.
Published US reports of Dasyatis include:
Leriche (1942) erected D. alveolatus for teeth from Travis Co,, TX, a locale which is thought to include both Late Maastrichtian and Paleocene material1. The figured specimens (Plate 1, Fig. 1-4) are very generic in design.
Welton & Farish (1993: 156) included as Dasyatis sp three teeth from the Texas Cretaceous (Cenomanian-Maastrichtian). One of these teeth (Fig. 3) conforms quite well with those of the extant Dasyatis.
Case (1994) included D. tricuspidatus in the Late Paleocene - Early Eocene fauna of Mississippi.
Case & Cappetta (1997:152) erected Dasyatis commercensis for teeth from the Kemp Clay (Late Maastrichtian) of Texas; they did not equate them with those in Welton & Farish which they viewed as different (the Fig. 1 design they included as Texabatis).
Hartstein et al (1999:18) reported Dasyatis sp from the Maastrichtian of Maryland.
Müller (1999: 60-61) included the two more common Lee Creek taxa as Dasyatis undescribed.
Purdy et al (2001: 90-93) attributed stingray material from Lee Creek to extant taxa:
- Dasyatis sayi (LESUER, 1817) - multiple teeth from Pungo River (units 1-5) and Yorktown (1-2).
- D. cf americana HILDEBRAND & SCHROEDER 1928 - single tooth from Lower Pungo River (units 1-3).
- D. centroura (MITCHILL 1814) - multiple dermal denticles/scutes.
Becker et al (2006: 710) reported Dasyatis sp from the Maastrichtian of Arkansas The figured specimen (Fig. 33-37) does not compare well with D. commercensis and might better referred to as only a dasyatid.
To ascribe a tooth to the paleontological genus "Dasyatis", I (and I'm only speaking for myself) require several specific characteristics to be present.
Roots bilobate and lingually directed (a strong slope of the labial lobe face)
Lobes separated by a wide and deep nutrient groove
A large central foramen or a group of smaller foramina
The crown lacks a distinct lingual uvula & bears a transverse ridge
Viewed laterally, the crown extends well beyond the labial face of the root
Collateral data which would tend to increase the confidence level include:
Tooth variations which suggest a Dasyatis-like dentition
Dasyatis-like dermal denticles present in the sediments
Black Creek Group -- Late Cretaceous
As noted above, there have been scattered reports of Late Cretaceous dasyatids along the Gulf Coast and none from North Carolina. While processing reworked material, two single crowns were recovered that appeared to represent dasyatid teeth; despite missing roots, the crown-design suggested Texabatis CAPPETTA & CASE 1997. As a number of members the Texas Kemp Clay fauna are represented in NC, teeth of D. commercensis (Fig. & ) have been included for reference purposes. The tooth-design included as dasyatid sp (Fig. ) is very similar to Hamrabatis weltoni CASE & CAPPETTA, 1997 (a rajiform) but not considered as such on the website.
Aquia Formation -- Selandian
Except for those of Hypolophodon, dasyatid teeth are not common in the Palaeocene sediments of the Aquia Formation. The few recovered specimens seen by the author, all resemble the below tooth-design.
Nanjemoy Formation -- Ypresian
Despite the abundance of batoid teeth in the Nanjemoy fauna, "Dasyatis" teeth must be deemed rare. The two specimens known to the author both reflect a similar morphology. Clearly Dasyatis in design, little more can be said. The reader should note that the uvula-like structures above each lobe are associated with tightly adjoining teeth in a dentition and are not necessarily a diagnostic characteristic.
Castle Hayne Formation -- Lutetian
As seen in the Ypresian, the Dasyatis-like tooth-design remains a rare find for collectors in the North American Lutetian. This scarcity can not be attributed solely to size -- they appear to be generally under-represented in Eocene faunas. In Oligocene sediments (i.e. Old Church, pers. obs.) they appear to become less rare, but continue to be an unusual find.
Dasyatis-like teeth become common in the Miocene sediments. They appear in abundance in the Calvert & Pungo River Formations and the Round Mountain Silt of California. The Lee Creek material is discussed in greater detail on the
.Lee Creek Stingray page.
||Earl Manning (pers. com 2007) commented, "...thought to be Early Paleocene (Danian) by Leriche in the paper, but were actually reworked from the Late. Maastrichtian Kemp Fm. into the Danian Kincaid Fm. at the old Littig Clay Pit, in Texas. I don't believe either Case or Cappetta (or Welton & Farish earlier) understood that...".|
Selected References (additional in Bibliography)
Becker, M, Chamberlain, J and Wolf, G., 2006. Chondrichthyans from the Arkadelphia Formation (Upper Cretaceous: Upper Maastrichtian) of Hot Spring County, Arkansas. Journal of Paleontology; 80:4; pp 700-716.
Cappetta, H., 1987. Chondrichthyes II: Mesozoic and Cenozoic Elasmobranchii. Handbook of Paleoichthyology, 3B. Gustav Fischer Verlag, Stuttgart and New York, 193 pp.
Case, G., 1994. Fossil Fish Remains fron the Late Paleocene Tuscahoma and Early Eocene Bashi Formations of Meridian, Lauderdale County, Mississippi. Palaeontographica Abt. A, 230, pp 97-138.
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, VI:17-23.
Leriche, M., 1942. Contribution à l'étude des faunes ichthyologiques marines des terrains Tertiaires de la Plaine Côtière Atlantique et du centre des Etats Unis. Mémoire de la Société Géologique de France, Paris, new series, 43:1-111.
Müller, A. 1999. Ichthyofaunen aus dem atlantischen Tertiär der USA. Leipziger Geowissenschafteb, Leipzig, 9/10: 1-360.
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.
Welton, B. J. and R. F. Farish 1993. The Collector's Guide to Fossil Sharks and Rays from the Cretaceous of Texas. Before Time, Texas. 204 pp.