Pisco Formation Explained

The Pisco Formation is a geologic formation located in Peru, on the southern coastal desert of Ica and Arequipa. The approximately 640m (2,100feet) thick formation was deposited in the Pisco Basin, spanning an age from the Late Miocene up to the Early Pliocene, roughly from 9.6 to 4.5 Ma. The tuffaceous sandstones, diatomaceous siltstones, conglomerates and dolomites were deposited in a lagoonal to near-shore environment, in bays similar to other Pacific South American formations as the Bahía Inglesa and Coquimbo Formations of Chile.

The Pisco Formation is considered one of the most important Lagerstätten sites,^{[2] [3]} based on the large amount of exceptionally preserved marine fossils, including sharks (most notably megalodon), birds including penguins, whales and dolphins, marine crocodiles, and Thalassocnus, a marine giant sloths.^[4]

Other famous fossils from this site include the giant raptorial sperm whale Livyatan,^[5] the sperm whale relative Acrophyseter, and the walrus-like dolphin Odobenocetops.^[6]

Description

The Pisco Formation of the Pisco Basin consists of tuffaceous sandstones, diatomaceous yellow to gray siltstones and a basal conglomerate.^[7] The formation is deposited from Pisco in the north to Yauca in the south. The northern portion is known as the Ocucaje Area and the southern part as the Sacaco Area.^[8] The total thickness of the formation is estimated at 640m (2,100feet).^[9] The formation unconformably overlies the Chilcatay and Caballas Formations.

Paleobiota of the Pisco Formation

The Pisco Formation has provided a rich resource of marine fauna, including marine mammals like cetaceans and seals, large fishes, reptiles, and penguins.^[10] It is also one of the richest sites in the world for fossil cetaceans, with close to 500 examples being found in the formation.^[11]

The oldest fossils of the aquatic sloth Thalassocnus (T. antiquus) come from the Aguada de Lomas horizon of the Pisco Formation and were dated at roughly 7 Ma. The youngest specimen (T. carolomartini) was found in the Sacaco horizon and dated to approximately 3 Ma.^[12] Thalassocnus was preyed upon by the probable apex predators of the environment, Livyatan and megalodon.^{[13] [14]} The youngest strata belonging to the formation have been dated at 2 Ma, corresponding to the Early Pleistocene (Uquian). Fossils of the modern Humboldt penguin were found in these deposits at the Yauca locality.^[15]

Birds

Taxa	Species	Locality	Materials	Description	Images	class=unsortable	Notes
Ciconiidae indet.	Gen. et sp. indet.			A stork
Fulmarus	Indet. sp.			A petrel
Morus	M. peruvianus	Sud-Sacaco	A set of limb elements	A relative of living gannets (Sulidae)
Perugyps	P. diazi	Sud-Sacaco	A limb element (right carpometacarpus).	A New World vulture (Cathartidae)
Pelagornis	Pelagornis sp.	Aguada de Lomas	Proximal carpometacarpus and right humerus ends	A pseudotoothed bird (Pelagornithidae)
Pelecanus	Indet. sp.			A pelican
Phalacrocorax	P. aff. bougainvillii			A relative of the Guanay cormorant
	cf. Phalacrocorax sp.			Probable cormorant remains
Rhamphastosula	R. aguierrei	Sud-Sacaco West	A cranium skull	A sulid bird with an enlarged beak
	R. ramirezi	Sud-Sacaco West	A skull
Spheniscus	S. humbodti	Sud Sacaco		Archaic Humboldt penguin		[16]
	S. megarhampus	Sud Sacaco	A partial skeleton
	S. muizoni	Cerro la Bruja	A partial skeleton.	The oldest banded penguin		align=center	[17] [18]
	S. urbinai	Sud-Sacaco West	A partial skeleton (partial skeleton with skull)	A larger banded penguin than S. muizoni
Sula	S. brandi	Cerro Colorado	A neurocranium lacking interorbital septum, lacrimals, palatines, pterygoids, jugals, quadrates, and right quadratojugal.Proximal portion of the beak, including most of the right dentary and angular.	Relatives of living boobies (Sulidae)
	S. magna	Sud Sacaco	A set of limb elements.
	S. sulita	Sud Sacaco	A limb element (coracoid)

Fish

Bony fish

Taxa	Species	Description	Images	class=unsortable	Notes
Alosinae	indet. sp.	A type of herring
Centropomidae	C. aff. Psamoperca	A snook
Triglidae	indet. sp.	A type of sea robin
Xiphiidae	indet. sp.	A swordfish
Sardinops	S. humboldti	A sardine

Rays

Taxa	Species	Description	Images	class=unsortable	Notes
Myliobatis	indet. sp.	A species of eagle ray

Sharks

Taxa	Species	Locality	Materials	Description	Images	class=unsortable	Notes
Carcharias	C. taurus			Archaic sand tiger shark
Carcharhinus	indet. sp.			A requiem shark
Carcharodon	C. carcharias			Archaic great white shark and close relative, respectively
	C. hubbelli
Cosmopolitodus	C. hastalis			The broad-toothed "mako"
Hexanchus	H. gigas			A cow shark
Isurus	I. oxyrhinchus			Archaic shortfin mako
Otodus	O. megalodon	Sub-Sacaco, Cerro Colorado, Aguada de Lomas, and El Jahuay	Multiple teeth, vertebrae, and dentition	The largest of the megatoothed sharks (Otodontidae) and of all fishes

Mammals

Cetaceans

Taxa	Species	Locality	Material	Description	Images	class=unsortable	Notes
Acrophyseter	A. deinodon	Sud-Sacaco	A skull	A small raptorial physeteroid (sperm whale relative)
	A. robustus	Cerro la Bruja	A skull
Atocetus	A. iquensis	Cero la Bruja	A skull	A small kentriodontid whale
Australithax	A. intermedia	El Jahuay		A long-snouted porpoise (Phocoenidae)
Balaenoptera	B. siberi	Aguada de Lomas	A partial skeleton	Archaic rorqual (Balaenopteridae)
Belonodelphis	B. peruanus	Cerro la Bruja	A skull	An elongated oceanic dolphin (Delphinidae)
Brachydelphis	B. jahuayensis	El Jahuay	A partial skull	An early oceanic dolphin (Delphinidae)
	B. mazeasi	El Jahuay	A partial skull
Brujadelphis	B. ankylorostris	Cerro la Bruja	A skull with complete jaw	A toothed whale of uncertain relation (incertae sedis)
Hemisyntrachelus	H. oligodon	Sud-Sacaco	A skull	An orca relative
Incakujira	I. anillodefuego	Aguada de Lomas	A preserved skeleton	A small rorqual (Balaenopteridae)
	I. fordycei	Aguada de Lomas	A preserved skeleton
Kogia	K. danomurai	Sacaco	A partial skull consisting of partial cranium, preserving the facial and dorsolateral regions of the cranial vault, but lacking most of the rostrum and basicranium	Basal member of Kogia, the genus of pygmy and dwarf sperm whale
Koristocetus	K. pescei	Aguada de Lomas	A partial skull	A small kogiid
Livyatan	L. melvillei	Cerro Colorado	A partially preserved skull with teeth and lower jaw	A very large raptorial physeteroid with 36cm (14inches) teeth
Lomacetus	L. ginsburgi	Aguada de Lomas		A porpoise relative (Phocoenidae)
Mamaziphius	M. reyesi	Cerros la Mama y la Hija	A partial skull consisting of partial cranium lacking most of the rostrum, the zygomatic processes of the squamosal, the occipital condyles and the ear bones	An early beaked whale (Ziphiidae)
Messapicetus	M. gregarius	Cerro Colorado	A partial skeleton consists of a skull, mandibles, humeri, vertebrae, and scapula	An early beaked whale (Ziphiidae)
Mesokentriodon	M. protohumboldti	Santa rosa	A sub-complete cranium, which lacks part of the right orbit, part of the basicranium, the ear bones, and teeth	A kentriodontid dolphin.
Miocaperea	M. pulchra	Aguada de Lomas	A partial skull	A cetothere whale
Ninoziphius	N. platyrostris	Sacaco	A partial skeleton	A giant beaked whale-relative
Odobenocetops	O. leptodon	Sacaco	A preserved skull	A tusked odontocete belonging to its unique family
	O. peruvianus	Sacaco	A partial skull
Piscobalaena	P. nana	Sud-Sacaco	A skull	A small cetothere
Piscocetus	P. sacaco	Sacaco	A partial skeleton	An extinct cetacean
Piscolithax	P. aenigmaticus	Aguada de Lomas	A partial skeleton	A porpoise relative (Phocoenidae)
Platyscaphokogia	P. landinii	Cerro Hueco la Zorra,	An incomplete skull lacking the tip of the rostrum and the basicranium.	An early beaked whale (Ziphiidae)
Pliopontos	P. littoralis	Sud-Sacaco	A partial skull	An early oceanic dolphin (Delphinidae)
Scaphokogia	S. cochlearis	Aguada de Lomas		An extinct kogiid

Pinnipeds

Seals

Taxa	Species	Locality	Material	Description	Images	class=unsortable	Notes
Acrophoca	A. longirostirus	Sub-Sacaco	A partial skull.	Archaic southern seal (Monachinae)
Australophoca	A. changorum	Aguada de Lomas	A partial skeleton consists of incomplete right ulna, right radius, right and left humeri, and other unidentified remains.	A phocidae seal.
Hadrokirus	H. martini	Sub-Sacaco	A partial skull	Archaic southern seal (Monachinae)
Hydrarctos	H. lomasiensis	Sub-Sacaco	A skull.	A sea lion and fur seal relative (Otariidae)
Icaphoca	I. choristodon	Cerro La Bruja	A subcomplete skull with associated left and right mandibles, atlas, axis, third, fourth, and fifth cervical vertebrae.	Archaic southern seal (Monachinae)		[19]
Magophoca	M. brevirostris	Cerro la Bruja	A partial skeleton of a male.	Archaic southern seal (Monachinae)
Piscophoca	P. pacifica	Sub-Sacaco	A partial skull	Archaic southern seal (Monachinae)

Xenarthrans

Sloths

Taxa	Species	Locality	Materials	Description	Images	class=unsortable	Notes
Thalassocnus	T. antiquus	Aguada de Lomas	A partial skeleton including the skull, mandible, and most of the postcranial skeleton.	a semi-aquatic giant sloth inhabiting marine environments		[20]
	T. carolomartini	Sacaco	An associated skull and mandible and two articulated hands, probably belonging to the same individual.
	T. littoralis	Sud-Sacaco	A skull with missing jugals.
	T. natans	Sud-Sacaco	A skull, mandible, and partial skeleton.

Mollusks

Bivalves

Taxa	Species	Description	Images	class=unsortable	Notes
Dosinia	indet. sp.

Polychaetes

Taxa	Species	Description	Images	class=unsortable	Notes
Diplochaetetes	D. mexicanus	A cirratulid bristle worm

Gastropods

Taxa	Species	Description	Images	class=unsortable	Notes
Acanthina	A. obesa
	A. triangularis
Concholepas	C. kieneri
Herminespina	indet. sp.

Reptiles

Crocodilians

Taxa	Species	Locality	Materials	Description	class=unsortable	Images	Notes
Eusuchia	indet. sp.
Piscogavialis	P. jugaliperforatus	Sacaco	A partial skeleton and a skull.	A gryposuchine (gharial relative)
	P. laberintoensis	Laberinto area, Ladera de Lisson Hill	A complete skull and mandible, along with postcranial elements
Sacacosuchus	S. cordovai	Sacaco	A nearly complete skull	A gharial relative (Gavialidae)

Turtles

Taxa	Species	Locality	Materials	Description	class=unsortable	Images	Notes
Pacifichelys	P. urbinai			A sea turtle (Cheloniidae)
Chelonia	indet. sp.			Green sea turtle relative

Correlations

Laventan

Laventan correlations in South America

Formation					Pisco							Map
Basin												align=center rowspan=17
Boreostemma	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Hapalops	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Miocochilius	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Theosodon	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Xenastrapotherium	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Rodents	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Birds	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Terror birds	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Reptiles	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
Insects	align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center		align=center
	Fluvial			Fluvio-deltaic		Fluvio-lacustrine		Fluvio-deltaic			Fluvial
Volcanic	Yes

See also

• Bahía Inglesa Formation, contemporaneous fossiliferous formation of Chile
• Castilletes Formation, contemporaneous fossiliferous formation of the Cocinetas Basin, Colombia
• Cerro Ballena, contemporaneous fossil site of the Bahía Inglesa Formation of Chile
• Coquimbo Formation, contemporaneous fossiliferous formation of Chile
• Collón Curá Formation, contemporaneous fossiliferous formation of Patagonia, Argentina
• Honda Group, contemporaneous fossiliferous formation of Colombia
• Navidad Formation, contemporaneous fossiliferous formation of Chile
• Pebas Formation, contemporaneous fossiliferous formation of the Amazon Basin
• Urumaco, contemporaneous fossil site of the Falcón Basin, Venezuela

References

Bibliography

Further reading

• A. Alván, J. Apolín, and C. Chacaltana. 2004. Los dientes de Seláceos (Condrichthyies) y su aplicación estratigráfica en Las Lomas de Ullujaya (Ica, Perú). XIII Congreso Peruano de Geología. Resúmenes Extendidos 595–598
• A. Collareta, O. Lambert, W. Landini, C. Di Celma, E. Malinverno, R. Varas-Malca, M. Urbina and G. Bianucci. 2017. Did the giant extinct shark Carcharocles megalodon target small prey? Bite marks on marine mammal remains from the late Miocene of Peru. Palaeogeography, Palaeoclimatology, Palaeoecology 469:84-91
• R. Esperante, L. Brand, K. E. Nick, O. Poma, and M. Urbina. 2008. Exceptional occurrence of fossil baleen in shallow marine sediments of the Neogene Pisco Formation, Southern Peru. Palaeogeography, Palaeoclimatology, Palaeoecology 257:344-360
• A. Gioncada, A. Collareta, K. Gariboldi, O. Lambert, C. Di Clema, E. Bonaccorsi, M. Urbina and G. Bianucci. 2016. Inside baleen: Exceptional microstructure preservation in a late Miocene whale skeleton from Peru. Geology
• C. S. Gutstein, M. A. Cozzuol, A. O. Vargas, M. E. Suarez, C. L. Schultz and D. Rubilar-Rogers. 2009. Patterns of skull variation of Brachydelphis (Cetacea, Odontoceti) from the Neogene of the Southeastern Pacific. Journal of Mammalogy 90(2):504-519
• O. Lambert, A. Collareta, W. Landini, K. Post, B. Ramanssamy, C. Di Celma, M. Urbina and G. Bianucci. 2015. No deep diving: evidence of predation on epipelagic fish for a stem beaked whale from the Late Miocene of Peru. Proceedings of the Royal Society B 282:20151530
• J. Machare, T. DeVries, and E. Fourtanier. 1988. Oligo-Miocene transgression along the Pacific margin of South America: new paleontological and geological evidence from the Pisco basin (Peru). Géodyynamique 3(1–2):25-37
• R. Marocco and C. de Muizon. 1988. Los vertebrados del Neogeno de La Costa Sur del Perú: Ambiente sedimentario y condiciones de fosilización. Bulletin de l'Institut Français d'Études Andines 17(2):105-117
• C. de Muizon and D. P. Domning. 1985. The first records of fossil sirenians in the southeastern Pacific Ocean. Bulletin du Museum National d'Histoire Naturelle. Section C: Sciences de la Terre: Paléontologie, Géologie, Minéralogie, Paris: Muséum National d'Histoire Naturelle 7(3):189-213
• C. de Muizon. 1983. Pliopontos littoralis un nouveau Platanistidae Cetacea du Pliocene de la cote peruvienne. Comptes Rendus de l'Académie des Sciences Paris Série II (296)1101-1104
• C. de Muizon. 1978. Arctocephalus (Hydrarctos) lomasiensis, subgen. nov. et nov sp., un nouvel Otariidae du Mio-Pliocene de Sacaco. Bulletin de l'Institute Français d'Études Andines 7(3–4):169-189
• M. Urbina and M. Stucchi. 2005. Los cormoranes (Aves: Phalacrocoracidae) del Mio-Plioceno de la Formacion Pisco, Peru. Boletin de la Sociedad Geologica del Peru 99:41-49
• R. M. Varas Malca and A. Valenzuela Toro. 2011. A basal monachine seal from the middle Miocene of the Pisco Formation, Peru. Ameghiniana 48(4):R216-R217
• T. J. DeVries. 2008. Pliocene and Pleistocene Fissurella Bruguiére, 1789 (Gastropoda: Fissurellidae) from Southern Peru. The Veliger 50(2):129-148
• T. J. DeVries. 2007. Cenozoic Turritellidae (Gastropoda) from southern Peru. Journal of Paleontology 81(2):331-351
• T. J. DeVries, L. T. Groves, and M. Urbina. 2006. A new early Miocene Muracypraea Woodring, 1957 (Gastropoda: Cypraeidae) from the Pisco Basin of southern Peru. The Nautilus 120(3):101-105
• T. J. DeVries. 2003. Acanthina Fischer von Waldheim, 1807 (Gastropoda: Muricidae), an ocenebrine genus endemic to South America. The Veliger 46(4):332-350
• T. J. DeVries. 1997. Neogene Ficus (Mesogastropoda: Ficidae) from the Pisco Basin (Peru). Boletín de la Sociedad Geológica de Perú 86:11-18

Notes and References

1. Ochoa . Diana . DeVries . Thomas J. . Quispe . Kelly . Barbosa-Espitia . Angel . Salas-Gismondi . Rodolfo . Foster . David A. . Gonzales . Renzo . Revillon . Sidoine . Berrospi . Raul . Pairazamán . Luis . Cardich . Jorge . Perez . Alexander . Romero . Pedro . Urbina . Mario . Carré . Matthieu . 2022 . Age and provenance of the Mio-Pleistocene sediments from the Sacaco area, Peruvian continental margin . Journal of South American Earth Sciences . 116 . 103799 . 10.1016/j.jsames.2022.103799 . 2022JSAES.11603799O . 0895-9811.
2. Brand et al., 2004
3. Brand et al., 2011
4. De Muizon et al., 2003
5. Lambert et al., 2010
6. De Muizon & Domning, 2002
7. Báez Gómez, 2006, p.65
8. Stucchi, 2007, p.368
9. Altamirano Sierra, 2013, p.3
10. Báez Gómez, 2006, p.66
11. Poma Porras et al., 2009, p.86
12. De Muizon et al., 2004, p.287
13. Parham & Pyenson, 2010, p.231
14. Bianucci et al., 2015, p.543
15. Stucchi, 2007, p.370
16. Stucchi, 2007, p.370
17. Göhlich, 2007, p.287
18. Stucchi, 2007, p.369
19. Dewaele, L.; de Muizon, C. (2025). "Icaphoca choristodon n. gen., n. sp., a new monachine seal (Carnivora, Mammalia) from the Neogene of Peru". Geodiversitas. 47 (11): 465–499. doi:10.5252/geodiversitas2025v47a11.
20. McDonald, H. & de Muizon, Christian. (2002). The cranial anatomy of Thalassocnus (Xenarthra, Mammalia), a derived nothrothere from the Neogene of the Pisco Formation (Peru). Journal of Vertebrate Paleontology. 22. 349-365. 10.1671/0272-4634(2002)022%5B0349:TCAOTX%5D2.0.CO;2.