The Santa Rosa local fauna consists of the animals found in the

Paleogene The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...

fossil site of Santa Rosa in eastern Peru. The age of the Santa Rosa fauna is difficult to determine, but may be

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

(

Mustersan The Mustersan age is a period of geologic time (48.0–42.0 Ma) within the Eocene epoch of the Paleogene, used more specifically within the South American land mammal age (SALMA) classification. It follows the Casamayoran and precedes the Divisade ...

) or

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

(

Deseadan The Deseadan ( es, Deseadense) age is a period of geologic time (29.0–21.0 Ma) within the Oligocene epoch of the Paleogene to the Early Miocene epoch of the Neogene, used more specifically within the SALMA classification of South America. It fo ...

History and context

Few fossils have been found in the vast rainforests of the Amazon Basin, and Santa Rosa was the first

fauna to be discovered in the region. The Santa Rosa local fauna was discovered in July 1995, and the discovery was briefly reported in 1996. In 1998, further fossil samples were taken at the site. Though not all of the material had been sorted, a report on the fauna was published in 2004 in a volume edited by Kenneth Campbell of the

Natural History Museum of Los Angeles County The Natural History Museum of Los Angeles County is the largest natural and historical museum in the western United States. Its collections include nearly 35 million specimens and artifacts and cover 4.5 billion years of history. This large coll ...

. The publication was reviewed favorably by Bruce MacFadden in the ''

Journal of Mammalian Evolution The ''Journal of Mammalian Evolution'' is the official journal of the Society for the Study of Mammalian Evolution. The journal is peer-reviewed Bi-monthly is a multidisciplinary forum devoted to studies on the comparative morphology, molecular ...

''.

Location and geology

The Santa Rosa fossil site is located in eastern Peru's

Atalaya Province Atalaya is the largest of four provinces in the Ucayali Region, in the central Amazon rainforest of Peru. Languages According to the 2007 census, Spanish was spoken as a first language by 49.1% of the population, while 37.0% spoke Asháninka, 1 ...

. It is about north of the town of Breu, south of the Brazilian border, and north of a small village named Santa Rosa. It is on the left (west) bank of the Río Yurúa at an altitude of . The fossils were found in coarse

fluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...

deposits that form thin

lenses A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...

along the bank of the river. There is a number of similar rock units—so-called "red beds"—in the Tertiary deposits of western Amazonia, including eastern Peru, and it is difficult to assign the isolated Santa Rosa outcrop to any of them. However, Campbell and colleagues suggested on the basis of the stage of evolution of the rodents and marsupials found that Santa Rosa dates to the

South American Land Mammal Age, which is part of the

. This would make it likely that it is part of the Yahuarango Formation, which may be

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

to Eocene in age. On the other hand, they suggested that Santa Rosa could be younger, perhaps

, and could fall either into a continuation of the Yahuarango Formation or into the younger

Chambira Formation The Chambira River is a major tributary of the Marañón River, and has been the traditional territory of the Urarina peoples for at least the past 350 years, if not longer. Located in the Amazon jungle of Peru, otherwise known as the Selva, the Ch ...

. Indeed, María Vucetich noted in 2010 that some of the Santa Rosa rodents are similar to

(Oligocene) forms, and the

notoungulate Notoungulata is an extinct order of mammalian ungulates that inhabited South America from the early Paleocene to the Holocene, living from approximately 61 million to 11,000 years ago. Notoungulates were morphologically diverse, with forms resemb ...

s also suggest a younger age.

Fauna

The Santa Rosa local fauna contains mammals, other vertebrates, and some crabs and

charophyte Charophyta () is a group of freshwater green algae, called charophytes (), sometimes treated as a phylum, division, yet also as a superdivision or an unranked clade. The terrestrial plants, the Embryophyta emerged within Charophyta, possibly fro ...

algae. Not all of the fossils found at Santa Rosa have been described in detail yet, and not all the material retrieved has been sorted. Full descriptions have been published of the Santa Rosa marsupials, rodents, and notoungulates. Two single teeth that may represent a bat and a

gondwanathere Gondwanatheria is an extinct group of mammaliaforms that lived in parts of Gondwana, including Madagascar, India, South America, Africa and Antarctica during the Upper Cretaceous through the Paleogene (and possibly much earlier, if '' Allostaffia ...

have also been described. Other fossils found at Santa Rosa have not been described in detail. There are some

xenarthra Xenarthra (; from Ancient Greek ξένος, xénos, "foreign, alien" + ἄρθρον, árthron, "joint") is a major clade of placental mammals native to the Americas. There are 31 living species: the anteaters, tree sloths, and armadillos. Ex ...

ns, numerous fish representing at least five

families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideall ...

, many

crocodilia Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest living ...

ns, some turtles, possibly some lizards, and a few fossils of amphibians and birds. Crab claws found at the site probably represent the family Pseudothelphusiidae. The marsupial fauna of Santa Rosa is known from 79 isolated teeth, which represent eleven species. The fauna is taxonomically diverse, comprising members of the orders

Microbiotheria Microbiotheria is an australidelphian marsupial order that encompasses two families, Microbiotheriidae and Woodburnodontidae, and is represented by only one extant species, the monito del monte, and a number of extinct species known from fossi ...

(represented among living marsupials only by the

monito del monte The monito del monte or colocolo opossum, ''Dromiciops gliroides'', also called ''chumaihuén'' in Mapudungun, is a diminutive marsupial native only to southwestern South America (Argentina and Chile). It is the only extant species in the ancient ...

Paucituberculata Paucituberculata is an order of South American marsupials. Although currently represented only by the seven living species of shrew opossums, this order was formerly much more diverse, with more than 60 extinct species named from the fossil reco ...

(shrew opossums), Didelphimorphia (opossums), and the extinct

Sparassodonta Sparassodonta (from Ancient Greek, Greek to tear, rend; and , gen.

, ' The comma is a punctuation mark that appears in several variants in different languages. It has the same shape as an apostrophe or single closing quotation mark () in many typefaces, but it differs from them in being placed on the baseline ...

tooth) is an extinct order (biology), order of carnivore, carnivorous metatherian mammals native to South America, related to modern marsupials. They were once con ...

and

Polydolopimorphia Polydolopimorphia is an extinct order of metatherians, more closely related to extant marsupials than other extinct mammals. Known from the Paleocene-Pliocene of South America and the Eocene of Antarctica, they were a diverse group during the Pal ...

. Two genera, '' Wirunodon'' and '' Kiruwamaq'', cannot be assigned to any existing marsupial order. The largest species found, the sparassodont '' Patene campbelli'', was cat-sized, but most species were the size of a mouse. Most Santa Rosa marsupials are thought to have been

frugivore A frugivore is an animal that thrives mostly on raw fruits or succulent fruit-like produce of plants such as roots, shoots, nuts and seeds. Approximately 20% of mammalian herbivores eat fruit. Frugivores are highly dependent on the abundance an ...

s and/or

insectivore A robber fly eating a hoverfly An insectivore is a carnivorous animal or plant that eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects. The first vertebrate insectivores wer ...

s; on the other hand, ''Patene'' was a carnivore. The most common species found, the polydolopimorphian '' Wamradolops tsulludon'', shows features that suggest it was adapted for breaking down hard food items such as seeds or bark. Hundreds of rodent fossils have been found at Santa Rosa, many of which cannot be identified precisely. These rodents are referable to the

caviomorph Caviomorpha is the rodent infraorder or parvorder that unites all New World hystricognaths. It is supported by both fossil and molecular evidence. The Caviomorpha was for a time considered to be a separate order outside the Rodentia, but is now a ...

group of rodents, which is unique to the Americas, and includes at least eleven species classified in the families Erethizontidae (New World porcupines),

Echimyidae Echimyidae is the family of neotropical spiny rats and their fossil relatives. This is the most species-rich family of hystricognath rodents. It is probably also the most ecologically diverse, with members ranging from fully arboreal to terres ...

(spiny rats), and

Agoutidae A paca is a member of the genus ''Cuniculus'' of ground-dwelling, herbivorous rodents in South America, South and Central America. It is the only genus in the family (biology), family Cuniculidae. Pacas are large rodents with dots and stripes ...

(agoutis). All Santa Rosa rodents share a common morphological pattern of the teeth, suggestive of a basal place in the caviomorph radiation. The extinct "ungulate" order

Notoungulata Notoungulata is an extinct order of mammalian ungulates that inhabited South America from the early Paleocene to the Holocene, living from approximately 61 million to 11,000 years ago. Notoungulates were morphologically diverse, with forms resemb ...

is represented by a few fossils only. Four isolated teeth may represent the same species, a sheep-sized member of the suborder

Toxodontia Toxodontia. Retrieved April 2013. is a suborder of the meridiungulate order Notoungulata. Most of the members of the five included families, including the largest notoungulates, share several dental, auditory and tarsal specializations. The gr ...

. A single, very small tooth may belong to a member of the toxodont family

Notohippidae Notohippidae is a paraphyly, paraphyletic extinct Family (biology), family of Notoungulata, notoungulate mammals from South America. Notohippids are known from the Eocene and Oligocene Epoch (reference date), epochs.McKenna, Malcolm C., and Bell ...

. A jaw fragment is referable to the family

Interatheriidae Interatheriidae is an extinct family of notoungulate mammals from South America. Interatheriids are known from the Middle Eocene (Mustersan) to the Early Pliocene (Montehermosan).McKenna & Bell, 1997Linares, 2004 These animals were principally sm ...

(suborder

Typotheria Typotheria is a suborder of the extinct mammalian order Notoungulata Notoungulata is an extinct order of mammalian ungulates that inhabited South America from the early Paleocene to the Holocene, living from approximately 61 million to 11,0 ...

). A single damaged lower molar documents the possible presence of a bat at Santa Rosa. The specimen is fragmentary enough that it cannot be identified positively as a bat. It shows some features that suggest a relationship with the living bat family Noctilionidae (bulldog bats). When published, this specimen represented the oldest known South American bat, but an older bat was described from Argentina in 2005. Another isolated tooth,

LACM 149371 LACM 149371 (Natural History Museum of Los Angeles County specimen 149371)Goin et al., 2004, p. 145 is an enigmatic fossil mammalian tooth from the Paleogene (66 to 23 million years ago, mya) of Peru. It is from the Santa Rosa fossil site, which is ...

, cannot be aligned securely with any mammalian group. Francisco Goin and colleagues, who described this specimen, tentatively suggested that it represents an upper molar of a member of the family

Ferugliotheriidae Ferugliotheriidae is one of three known family (biology), families in the order (biology), order Gondwanatheria, an enigmatic group of extinction, extinct mammals. Gondwanatheres have been classified as a group of uncertain affinities or as membe ...

, part of the ancient and enigmatic group

Gondwanatheria Gondwanatheria is an extinct group of mammaliaforms that lived in parts of Gondwana, including Madagascar, India, South America, Africa and Antarctica during the Upper Cretaceous through the Paleogene (and possibly much earlier, if '' Allostaff ...

. If this identification is correct, it would be among the youngest known gondwanatheres.

Faunal list

The following species of mammals have been recorded at Santa Rosa: * Order

Primate Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...

s ** Suborder

Anthropoidea The simians, anthropoids, or higher primates are an infraorder (Simiiformes ) of primates containing all animals traditionally called monkeys and apes. More precisely, they consist of the parvorders New World monkeys (Platyrrhini) and Catarrhi ...

*** Family indeterminate **** Genus '' Perupithecus'' ***** '' Perupithecus ucayaliensis'' * Order indeterminate ** Possibly family

(

) * Order Didelphimorphia (opossums) **

cf. The abbreviation ''cf.'' (short for the la, confer/conferatur, both meaning "compare") is used in writing to refer the reader to other material to make a comparison with the topic being discussed. Style guides recommend that ''cf.'' be used onl ...

Family

Herpetotheriidae Herpetotheriidae is an extinct family of metatherians, closely related to marsupials. Species of this family are generally reconstructed as terrestrial, and are considered morphologically similar to modern opossums. Fossils of herpetotheriids com ...

*** Genus '' Rumiodon'' **** '' Rumiodon inti'' **** ''Rumiodon'' sp. * Order

Sparassodonta Sparassodonta (from Ancient Greek, Greek to tear, rend; and , gen.

tooth) is an extinct order (biology), order of carnivore, carnivorous metatherian mammals native to South America, related to modern marsupials. They were once con ...

** Family Hathliacynidae *** Genus '' Patene'' **** '' Patene campbelli'' * Order

** Family Prepidolopidae *** Genus '' Incadolops'' **** '' Incadolops ucayali'' ** Family indeterminate *** Genus '' Hondonadia'' **** '' Hondonadia pittmanae'' *** Genus '' Wamradolops'' **** '' Wamradolops tsullodon'' * Order

(shrew opossums) ** Family

Caenolestidae The family Caenolestidae contains the seven surviving species of shrew opossum: small, shrew-like marsupials that are confined to the Andes mountains of South America. The order is thought to have diverged from the ancestral marsupial line very e ...

*** Genus '' Perulestes'' **** '' Perulestes cardichi'' **** '' Perulestes fraileyi'' ** cf. Family Palaeothentidae *** Genus '' Sasawatsu'' **** '' Sasawatsu mahaynaq'' * Order

(monito del monte) ** Family

Microbiotheriidae Microbiotheriidae is a family of australidelphian marsupials represented by only one extant species, the monito del monte, and a number of extinct species known from fossils in South America, Western Antarctica, and northeastern Australia. Micr ...

*** Genus '' Kirutherium'' **** '' Kirutherium paititiensis'' * Marsupialia, order and family indeterminate ** Genus '' Kiruwamaq'' *** '' Kiruwamaq chisu'' ** Genus '' Wirunodon'' *** '' Wirunodon chanku'' * Order

** Suborder

*** Family, genus and species indeterminate (perhaps more than one species) *** cf. Family

**** Genus and species indeterminate ** Suborder

*** Family

**** Genus and species indeterminate * Order

Rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...

ia (rodents) ** Family Erethizontidae (New World porcupines) *** Genus '' Eopululo'' **** '' Eopululo wigmorei'' ** Family

(agoutis) *** Genus '' Eobrasinamys'' **** '' Eobrasinamys riverai'' **** '' Eobranisamys romeropittmanae'' *** Genus '' Eoincamys'' **** '' Eoincamys ameghinoi'' **** '' Eoincamys pascuali'' *** Genus '' Eopicure'' **** '' Eopicure kraglievichi'' *** Genus and species indeterminate A *** Genus and species indeterminate B *** Genus and species indeterminate C ** Family

(spiny rats) *** Genus '' Eodelphomys'' **** '' Eodelphomys almeidacomposi'' *** Genus '' Eoespina'' **** '' Eoespina woodi'' *** Genus '' Eosachacui'' **** '' Eosachacui lavocati'' *** Genus '' Eosallamys'' **** '' Eosallamys paulacoutoi'' **** '' Eosallamys simpsoni'' *** Genus and species indeterminate A *** Genus and species indeterminate B *** Genus and species indeterminate C * Order

Chiroptera Bats are mammals of the Order (biology), order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in fli ...

(bats) ** Family, genus, and species indeterminate

References

Bibliography

* * * * * * * * * * * * * *{{cite book , last1 = Woods , first1 = C.A. , last2 = Kilpatrick , first2 = C.W. , year = 2005 , chapter-url = http://www.bucknell.edu/msw3 , publisher = Johns Hopkins University Press , location = Baltimore, Maryland , isbn = 978-0-8018-8221-0 , pages = 1538–1600 , chapter = Infraorder Hystricognathi , title = Mammal Species of the World: A Taxonomic and Geographic Reference , edition = 3rd , editor1-last = Wilson , editor1-first = D.E. , editor2-last = Reeder , editor2-first = D.M Cenozoic paleontological sites of South America Eocene paleontological sites Oligocene paleontological sites Paleogene Peru Geology of Peru Paleontology in Peru Amazonas Region Prehistoric fauna by locality