Chandler Bridge Formation

Chandler Bridge Formation
Stratigraphic range: Chattian (Arikareean) ~27–24  Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Formation
Unit of	Cooper Group
Underlies	Edisto Formation
Overlies	Ashley Formation
Lithology
Primary	Sandstone
Location
Coordinates	32°48′N79°48′W / 32.8°N 79.8°W / 32.8; -79.8
Approximate paleocoordinates	32°54′N74°12′W / 32.9°N 74.2°W / 32.9; -74.2
Region	South Carolina
Country	United States
Type section
Named for	Chandler Bridge
Chandler Bridge Formation (the United States) Show map of the United States Chandler Bridge Formation (South Carolina) Show map of South Carolina

The Chandler Bridge Formation is a geologic formation in South Carolina. It preserves fossils dating back to the Chattian (Late Oligocene) of the Paleogene period, corresponding to the Arikareean in the NALMA classification. ^[1] The formation overlies the Ashley Formation and is overlain by the Edisto Formation. ^[2]

Vertebrate paleofauna

Mammals

Carnivorans

Carnivorans reported from the Chandler Bridge Formation
Genus	Species	Presence	Material	Notes	Images
Phocidae	Gen. et. sp. indeterminate		Proximal portion of a right femur (ChM PV5712). [3]	"A taxon closely comparable to the most specialized phocid, the modern genus Cystophora".

Cetaceans

Cetaceans reported from the Chandler Bridge Formation
Genus	Species	Presence	Material	Notes	Images
Agorophiidae		Upper sandy unit. [4]		Referred to as Genus Y.
Agorophius	A. sp.		"ChM PV 4256 (a partial skull and mandible with isolated teeth and associated postcrania)". [5]	An odontocete.
Ankylorhiza	A. tiedemani		Partial skeleton (CCNHM 103). [6]	An odontocete also found in the Ashley and Belgrade formations.
Coronodon	C. newtonorum	A manmade exposure in the vicinity of North Charleston, South Carolina. [7]	Partial skeleton (ChM PV 2778). [7]	A toothed mysticete.
	C. planifrons	Drainage ditch in North Charleston, South Carolina. [7]	Partial skeleton (CCNHM 166) & isolated upper right M3 (CCNHM 8732). [7]	A toothed mysticete.
Cotylocara	C. macei	[8]		A xenorophid.
Echovenator	E. sandersi	"Drainage ditch associated with Limehouse Branch Creek, Berkeley County, South Carolina". [9]	A nearly-complete skull. [9]	A xenorophid.
Eomysticetus	E. carolinensis	Bed 2. [10]		A mysticete.
	E whitmorei	Bed 3, uppermost portion of the formation. [10]		A mysticete.
cf. Eurhinodelphinidae		Upper sandy unit. [4]
cf. Squalodelphinidae		Upper sandy unit. [4]
Squalodon			A premolar (BCGM 9198). [11]

Sirenians

Sirenians reported from the Chandler Bridge Formation
Genus	Species	Presence	Material	Notes	Images
Crenatosiren	C. olseni		[12]	A dugongid also known from the Ashley and Parachucla formations.
Metaxytherium	M. albifontanum		Remains of a subadult individual (SC 89.115) and a young adult individual (ChM PV4757). [13]	A dugongid also found in the Parachucla Formation.
Priscosiren	P. atlantica		SC 89.254. [14]	A dugongid.
Stegosiren	S. macei		[15]	A dugongid also found in the Ashley Formation.

Reptiles

Birds

Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon		Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Birds reported from the Chandler Bridge Formation
Genus	Species	Presence	Material	Notes	Images
Palaeochenoides	P. mioceanus		Distal end of a tarsometatarsus. [16]	A dubious pelagornithid, may instead be from the Cooper Formation.
Pelagornis	P. sandersi	Bed 2 near Charleston Airport. [17]		A pelagornithid.
Sulidae		Upper sandy unit. [4]
Tympanonesiotes	T. wetmorei		A very fragmentary piece of tarsometatarsus. [16]	A dubious pelagornithid, may instead be from the Cooper Formation.

Crocodilians

Crocodilians reported from the Chandler Bridge Formation
Genus	Species	Presence	Material	Notes	Images
Gavialosuchus	G. carolinensis		A tooth (BCGM 9197). [11]	Now moved to the genus Thecachampsa . [18]
Thecachampsa	T. carolinensis		A tooth (BCGM 9197). [11]	A gavialid.

Testudines

Testudines reported from the Chandler Bridge Formation
Genus	Species	Presence	Material	Notes	Images
Ashleychelys	A. palmeri		Multiple specimens. [19]	A cheloniid also found in the Ashley Formation.
Bairdemys	B. healeyorum		A largely complete skeleton and a partial anterior carapace. [20]	A podocnemid.
Carolinochelys	C. wilsoni	Upper sandy unit. [4]	Multiple specimens. [19]	A cheloniid.
cf. Egyptemys	cf. E. sp.	Bed 1. [21]	CCNHM 4289 (a ridged carapacial ossicle). [21]	A dermochelyid.
Natemys	N. sp. 1		CCNHM 4405.1–4405.5 (five associated non-ridged carapacial ossicles); CCNHM 5540, 5541, and 5542 (three non-ridged carapacial ossicles). [21]	A dermochelyid, also known from the Ashley Formation.
Procolpochelys	P. charlestonensis		ChM PV6056 (a largely complete carapace associated with a few fragmentary vertebrae, pectoral girdle elements, humerus, and femur) and a skull fragment. [19]	A cheloniid.
cf. Psephophorus	cf. P. sp.	Bed 1. [21]	CCNHM 5543 (an isolated ridged ossicle). [21]	A dermochelyid, also found in the Ashley Formation.

Fish

Bony fish

Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon		Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Bony Fish reported from the Chandler Bridge Formation
Genus	Species	Presence	Material	Notes	Images
Aglyptorhynchus	A. sp.		2 isolated vertebral centra. [11]
Cylindracanthus	C. sp.	Upper sandy unit. [4]		A billfish.
Histiophorus	H. rotundus		ChM PV4864. [22]	A swordfish, now reassigned to Xiphiorhynchus. [22]
Xiphiorhynchus	X. cf. X. aegyptiacus	"McKewn Subdivision, North Charleston, Dorchester County, South Carolina". [4]	A partial rostrum. [4]	A swordfish.
	X. rotundus		ChM PV4864. [22]	A swordfish.

Rays

Rays reported from the Chandler Bridge Formation
Genus	Species	Presence	Material	Notes	Images
Anoxypristis			A single rostral spine. [11]	A sawfish.
Dasyatidae	Dasyatidae gen. et. sp. indet.		Teeth (BCGM 9100 and 9101, SC 2009.18.19). [11]	A stingray.
Dasyatis	D. cavernosa		Teeth (BCGM 9096, 9097, and 9103, SC 2009.18.17). [11]	A stingray.
	D. rugosa		BCGM 9098 and 9099, SC 2009.18.18. [11]	A stingray.
Gymnura	G. sp.		A tooth (BCGM 9107). [11]	A butterfly ray.
Mobula	M. cf. M. loupianensis		BCGM 9133–9142, SC 2009.18.20. [11]
Myliobatinae	Myliobatinae gen. indet.		Partial medial teeth and complete lateral teeth (BCGM 9114–9117, SC 2009.18.22). [11]	An eagle ray.
Paramobula	P. fragilis		Teeth (BCGM 9111–9113, SC 2009.18.21). [11]
Plinthicus	P. stenodon	Upper sandy unit. [4]	BCGM 9118–9121, SC 2009.18.23 [11]	The oldest record of this species.
Raja	Raja mccollumi	"Summerville, Dorchester County, South Carolina". [11]	Teeth. [11]	A skate also found in the Ashley Formation.
	R. sp.		Teeth (BCGM 9087–9089, SC 2009.18.16). [11]	A skate with teeth twice as large as those of R. mccollumi, but far less common. [11]
Rhinoptera	R. cf. R. studeri		Teeth (BCGM 9122 and 9123, SC 2009.18.24). [11]	A cownose ray.
	R. sp.	Upper sandy unit. [4]		A cownose ray.
Rhynchobatus	R. pristinus		Teeth (BCGM 9084–9086, SC 2009.18.14). [11]	A wedgefish.

Sharks

Sharks reported from the Chandler Bridge Formation
Genus	Species	Presence	Material	Notes	Images
Alopias	A. cf. A. vulpinus		Teeth (BCGM 9046–9048, SC 2009.18.3). [11]	A thresher shark.
Bythaelurus	B. sp.		A fragmentary tooth (BCGM 9074). [11]	A catshark.
Carcharias	C. cuspidatus		Teeth (BCGM 9051 and 9052). [11]	A sand shark.
	C. sp.		A posterior tooth (BCGM 9053) and a lateral tooth from a very young individual (BCGM 9054). [11]	A sand shark.
Carcharhinus	C. gibbesi		BCGM 9056–9062, SC 2009.18.6. [11]	The most abundant non-batoid elasmobranch in the Chandler Bridge sample. [11]
	C. leucas	Upper sandy unit. [4]		The bull shark.
Carcharocles	C. angustidens	Upper sandy unit. [4]	Teeth. [23]	Reassigned to the genus Otodus .
	C. sp.		Teeth (BCGM 9055, SC 2009.18.5). [11]	Reassigned to the genus Otodus .
Cetorhinus	?C. parvus		Scales (BCGM 9049 and 9050, SC 2009.18.4). [11]	A basking shark.
Galeocerdo	G. 'casei'	Upper sandy unit. [4]
Galeorhinus	G. sp.		Teeth (BCGM 9080–9083, SC 2009.18.13). [11]	A houndshark.
Hemipristis	H. serra		Teeth (BCGM 9071–9073, SC 2009.18.10). [11]	A weasel shark.
Nebrius	N. cf. N. serra		A tooth (SC 2009.18.1). [11]	A nurse shark.
Otodus	O. angustidens	Upper sandy unit. [4]	Teeth. [23]	Assemblages dominated by teeth of juveniles and neonates, with few adults present, suggesting a nursery area for the species. [23]
	O. sp.		Teeth (BCGM 9055, SC 2009.18.5). [11]	A megatooth shark.
Physogaleus	P. aduncus		Teeth (BCGM 9063–9066, SC 2009.18.7). [11]	A ground shark.
	P. contortus	Upper sandy unit. [4]		A ground shark.
	P. sp.		Broken and/or abraded teeth (BCGM 9067 and 9068, SC 2009.18.8). [11]	A ground shark.
Rhincodon	R. cf. R. typus		Teeth (BCGM 9044 and 9045, SC 2009.18.2). [11]	The oldest fossil record of the whale shark.
Rhizoprionodon	R. sp.		Small, imperfectly preserved teeth (BCGM 9069 and 9070, SC 2009.18.9). [11]	A sharpnose shark.
Sphyrna	S. cf. S. media		BCGM 9075–9077, SC 2009.18.11. [11]	A hammerhead shark.
	S. zygaena		BCGM 9078 and 9079, SC 2009.18.12. [11]	The more common of the two hammerhead shark species found in the formation. [11]
Squatina	S. cf. S. angeloides		BCGM 9042 and 9043. [11]	An angelshark.

See also

• List of fossiliferous stratigraphic units in South Carolina
• Paleontology in South Carolina

References

1. Chandler Bridge Formation at Fossilworks.org
2. Albright et al., 2019, p.84
3. J., Ray, Clayton Edward. Emry, Robert (2002). Cenozoic mammals of land and sea : tributes to the career of Clayton E. Ray. Smithsonian Institution Press. pp. 179–183. OCLC   1035595001.
4. McCuen, William; Ishimori, Aika; Boessenecker, Robert (2020-07-13). "A New Specimen of Xiphiorhynchus sp. cf. aegyptiacus (Istiophoriformes, Xiphioidei, Xiphiidae) and Billfish Diversity in the Oligocene of South Carolina". Vertebrate Anatomy Morphology Palaeontology. 8: 98–104. doi: 10.18435/vamp29367 . ISSN   2292-1389. S2CID   225527250.
5. Boessenecker, Robert W.; Geisler, Jonathan H. (2018-09-28). "New records of the archaic dolphin Agorophius (Mammalia: Cetacea) from the upper Oligocene Chandler Bridge Formation of South Carolina, USA". PeerJ. 6: e5290. doi: 10.7287/peerj.5290v0.1/reviews/2 . PMC   6166619 . PMID   30280011.
6. Boessenecker, Robert W.; Churchill, Morgan; Buchholtz, Emily A.; Beatty, Brian L.; Geisler, Jonathan H. (2020-08-17). "Convergent Evolution of Swimming Adaptations in Modern Whales Revealed by a Large Macrophagous Dolphin from the Oligocene of South Carolina". Current Biology. 30 (16): 3267–3273.e2. Bibcode:2020CBio...30E3267B. doi: 10.1016/j.cub.2020.06.012 . ISSN   0960-9822. PMID   32649912. S2CID   220435400.
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10. Sanders, A. E.; Barnes, L. G. (2002-09-14). "Paleontology of the late Oligocene Ashley and Chandler Bridge Formations of South Carolina, 3: Eomysticetidae, a new family of primitive mysticetes". Smithsonian Contributions to Paleobiology. 93: 313–356.
11. "Late Oligocene sharks and rays from the Chandler Bridge Formation, Dorchester County, South Carolina, USA - Acta Palaeontologica Polonica". www.app.pan.pl. Retrieved 2022-09-06.
12. Domning, Daryl P. (1997-06-19). "Fossil Sirenia of the west Atlantic and Caribbean region. VI. Crenatosiren olseni (Reinhart, 1976)". Journal of Vertebrate Paleontology. 17 (2): 397–412. Bibcode:1997JVPal..17..397D. doi:10.1080/02724634.1997.10010984. ISSN   0272-4634.
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14. Vélez-Juarbe, Jorge; Domning, Daryl P. (2014-06-07). "Fossil Sirenia of the West Atlantic and Caribbean region: X. Priscosiren atlantica, gen. et sp. nov". Journal of Vertebrate Paleontology. 34 (4): 951–964. Bibcode:2014JVPal..34..951V. doi:10.1080/02724634.2013.815192. ISSN   0272-4634. S2CID   85297028.
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Bibliography

• Albright, L.B.; Sanders, A.E.; Weems, R.E.; Cicimurri, D.J.; Knight, J.L. (2019), "Cenozoic vertebrate biostratigraphy of South Carolina, U.S.A. and additions to the fauna", Bulletin of the Florida Museum of Natural History , 57 (2): 77–236, doi:10.58782/flmnh.qqgg4577 , retrieved 2020-03-27