New Egypt Formation
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The New Egypt Formation is a Late Cretaceous (late Maastrichtian-aged) geologic formation of the Monmouth Group in New Jersey, United States.
Description
The basal New Egypt is a massive clayey, glauconitic marl that closely resembles the Navesink Formation into which it grades below. Ammonites and other invertebrates found at the Spheno Run site correlate well with the middle Severn Formation of Maryland. Spheno Run has so far produced a remarkable number of vertebrate specimens, especially from marine reptiles, including: carapace elements from at least two species of turtles, Peritresius ornatus and Taphrosphys sulcatus; various bone elements from at least two species of mosasaurs including a sizable fragment of dentary bone from Prognathodon rapax and numerous shed teeth from Mosasaurus maximus.
Vertebrate remains also include material from sharks, particularly teeth and unusually large vertebral centra from an individual lamniform shark Squalicorax pristodontus, bony fish, and, rarely, dinosaurs. In addition to the vertebrate collection, Spheno Run also yields an abundance of invertebrate species including: twenty-two bivalves, seven gastropods, six cephalopods, and one each of echinoidea, porifera, and scaphopoda. It is rare to find such an extensive array of both vertebrate and invertebrate species within one horizon in New Jersey.
The New Egypt Formation preserves the most complete late Maastrichtian-aged dinosaur fauna from the eastern United States, providing an important record of the dinosaurs that inhabited Appalachia around this time. These remains belong to dinosaurs whose carcasses were washed out to sea, and preserve evidence of being submerged in water and scavenged by sharks & marine invertebrates. The most notable taxon from this formation is the tyrannosauroid Dryptosaurus, one of the few predatory theropods known from eastern North America. In addition, remains of indeterminate hadrosaurs, including potential lambeosaurines, are also known. The potential presence of lambeosaurines is notable, as very few other remains are known from eastern North America, and is not thought to have still inhabited North America so late into the Maastrichtian.
Vertebrate paleobiota
Cartilaginous fish
The following taxa are known:
Chimaeras
| Chimaeras of the New Egypt Formation | |||||||
|---|---|---|---|---|---|---|---|
| Genus | Species | Member | Location | Material | Notes | Images | Images |
| Edaphodon | E. mirificus | Barnsboro, Blackwood Terrace | A callorhinchid chimaera. | ||||
| Leptomylus | L. forfex | Barnsboro | A chimaeriform of uncertain affinities. |
Sharks
| Sharks of the New Egypt Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Member | Location | Material | Notes | Images |
| Brachaelurus | B. hornerstownensis | Shrewsbury | Arneytown | 1 tooth | A blind shark. Type locality for species. | |
| Chiloscyllium | C. sp. | Shrewsbury | Arneytown | 1 tooth | A bamboo shark. | |
| Cretalamna | C. appendiculata | Shrewsbury | Arneytown | 1 tooth | A megatooth shark. | |
| Ginglymostoma | G. cuspidata | Shrewsbury | Arneytown | 3 teeth | A nurse shark. Type locality for species. | |
| Hemiscyllium | H. sp. | Shrewsbury | Arneytown | 1 tooth | A bamboo shark. | |
| Proheterodontus | P. creamridgensis | Shrewsbury | Arneytown | 1 tooth | A bullhead shark. Type locality for species. | |
| Pseudodontaspis | P. cf. herbsti | Shrewsbury | Arneytown | 1 tooth | A sand shark. | |
| Scapanorhynchus | S. texanus | Blackwood Terrace | A goblin shark. | |||
| Serratolamna | S. serrata | Shrewsbury | Arneytown | 1 tooth | A serratolamnid mackerel shark. | |
| Squalicorax | S. kaupi | Shrewsbury | Arneytown | 1 tooth | A crow shark. | |
| S. pristodontus | Spheno Run, Blackwood Terrace | |||||
| Squatina | S. hassei | Shrewsbury | Arneytown | 4 teeth | An angelshark. |
Rays
| Rays of the New Egypt Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Member | Location | Material | Notes | Images |
| Dasyatis | D. newegyptensis | Shrewsbury | Arneytown | 3 teeth | A whiptail stingray. Type locality of species. | |
| Ischyrhiza | I. mira | Blackwood Terrace | An sawskate. | |||
| Protoplatyrhina | P. renae | Shrewsbury | Arneytown | 1 tooth | A hypsobatid ray. | |
| Ptychotrygon | P. sp. | Shrewsbury | Arneytown | 1 tooth | A ptychotrygonid sawskate. | |
| Rhinobatos | R. casieri | Shrewsbury | Arneytown | 2 teeth | A guitarfish. | |
| Rhombodus | R. binkhorsti | Shrewsbury | Arneytown | 2 teeth | A rhombodontid ray. | |
| R. laevis | 1 tooth | |||||
| Sclerorhynchus | S. pettersi | Shrewsbury | Arneytown | 2 rostra pieces | A sclerorhynchid sawskate. |
Ray-finned fish
| Actinopterygii of the New Egypt Formation | |||||||
|---|---|---|---|---|---|---|---|
| Genus | Species | Member | Location | Material | Notes | Images | Images |
| Anomoeodus | A. phaseolus | Blackwood Terrace | A pycnodont. |
Reptiles
Dinosaurs
| Dinosaurs of the New Egypt Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Member | Location | Material | Notes | Images |
| Dryptosaurus | D. aquilunguis | Barnsboro | Incomplete skeleton | A tyrannosauroid theropod, type locality of genus and species. One of the most complete theropod skeletons known from eastern North America. | ||
| "Hadrosaurus" | "H." minor | Barnsboro | A small-sized hadrosaurid ornithischian. Nomen dubium. | |||
| ?Lambeosaurinae indet. | Barnsboro | Partial forelimb | A hadrosaur bone potentially referable to a lambeosaurine. Notable for representing one of the only potential records of this group from eastern North America, and one of the latest records of this group from North America overall. |
Crocodylomorphs
| Crocodylomorphs of the New Egypt Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Member | Location | Material | Notes | Images |
| Hyposaurus | H. rogersii | Barnsboro | A dyrosaurid. |
Turtles
| Turtles of the New Egypt Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Member | Location | Material | Notes | Images |
| Agomphus | A. pectoralis | Barnsboro | A kinosternoid related to the hickatee. | |||
| Euclastes | E. wielandi | Barnsboro | A pancheloniid sea turtle. | |||
| Osteopygis | O. emarginatus | Barnsboro | A macrobaenid. | |||
| Peritresius | P. ornatus | Spheno Run | A pancheloniid sea turtle. | |||
| Taphrosphys | T. nodosus | Barnsboro, Spheno Run | A bothremydid side-necked turtle. | |||
| T. sulcatus |
Squamates
| Squamates of the New Egypt Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Member | Location | Material | Notes | Images |
| Mosasaurus | M. hoffmanni (=M. dekayi) | Barnsboro, Spheno Run | A mosasaurine mosasaur. | |||
| Prognathodon | P. rapax | Barnsboro, Spheno Run | A mosasaurine mosasaur. | |||
| Russellosaurina indet. | Barnsboro | A russellosaurine mosasaur. |
Invertebrate fossils
Bivalves
Cephalopods
See also
Bibliography
- Carter, M. T. W.; Johnson, R. O.; Chamberlain, J. A.; Mehling, C. (2008), "A new vertebrate fauna from the Late Cretaceous (Maastrichtian) New Egypt Formation of New Jersey", Abstracts with Programs - Geological Society of America, 40: 78–79
Further reading
- Brownstein, Chase Doran (2021), "Osteology and phylogeny of small-bodied hadrosauromorphs from an end-Cretaceous marine assemblage", Zoological Journal of the Linnean Society, 191: 180–200, doi:
- B. Stahl and D. Parris. 2004. The complete dentition of Edaphodon mirificus (Chondrichthyes: Holocephali) from a single individual. Journal of Paleontology 78(2):388-392
- W. B. Gallagher. 1993. The Cretaceous/Tertiary mass extinction event in the North Atlantic coastal plain. The Mosasaur 5:75-154
- W. B. Gallagher. 1984. Paleoecology of the Delaware Valley region. Part II: Cretaceous to Quaternary. The Mosasaur 2:9-43
- E. S. Gaffney. 1975. A revision of the side-necked turtle Taphrosphys sulcatus (Leidy) from the Cretaceous of New Jersey. American Museum Novitates (2571)1-24
- E. L. Troxell. 1925. Hyposaurus, a marine crocodilian. American Journal of Science 9:489-514
- G. R. Wieland. 1905. Structure of the Upper Cretaceous turtles of New Jersey: Agomphus. The American Journal of Science, series 4 20:430-444
- G. R. Wieland. 1904. Structure of the Upper Cretaceous turtles of New Jersey: Lytoloma. The American Journal of Science, series 4 18:183-196
- E. D. Cope. 1875. The Vertebrata of the Cretaceous formations of the west. Report of the United States Geological and Geographical Survey of the Territories 2:1-303
- E. D. Cope. 1870. Synopsis of the Extinct Batrachia, Reptilia and Aves of North America. Part II. Transactions of the American Philosophical Society, New Series 14:105-235
- E. D. Cope. 1866. [On the remains of a gigantic extinct dinosaur, from the Cretaceous Green Sand of New Jersey]. Proceedings of the Academy of Natural Sciences of Philadelphia 18:275-279