Río Chico Oeste (Eocene to of Argentina)

Also known as west of Río Chico

Where: Chubut, Argentina (45.1° S, 68.4° W: paleocoordinates 47.6° S, 58.7° W)

• coordinate based on political unit

• local area-level geographic resolution

When: Barrancan-Vacan zone, Lutetian to Lutetian (47.8 - 38.0 Ma)

• Casamayoran SALMA. According to Cifelli (1985), this locality is mostly early Barrancan but partly Vacan in age.

•Middle Eocene according to Woodburne et al. (2014).

Environment/lithology: terrestrial; lithology not reported

Size class: mesofossils

Primary reference: R. Cifelli. 1985. Biostratigraphy of the Casamayoran, Early Eocene of Patagonia. American Museum Novitates 2820:1-26 [J. Zijlstra/J. Zijlstra]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 176164: authorized by Jelle Zijlstra, entered by Jelle Zijlstra on 30.01.2016, edited by Philip Mannion

Creative Commons license: CC BY (attribution)

Taxonomic list

Mammalia
 Astrapotheria - Trigonostylopidae
"Trigonostylops wortmani" = Trigonostylops wortmani, "Trigonostylops scabellum n. sp." = Trigonostylops wortmani4
"Trigonostylops wortmani" = Trigonostylops wortmani Ameghino 1897 placental
"Trigonostylops scabellum n. sp." = Trigonostylops wortmani4 Ameghino 1897 placental
MACN 10657, maxilla P3-4
 Theriamorpha -
Carolozittelia tapiroides n. gen. n. sp.4
Carolozittelia tapiroides n. gen. n. sp.4 Ameghino 1901 placental
MACN 10666, maxilla M2-3 (lectotype), lower jaw fragments; MACN 10665, lower jaw fragments.
 Notoungulata -
"Pleurostylops glebosus n. gen. n. sp." = Pleurystylops glebosus4
"Pleurostylops glebosus n. gen. n. sp." = Pleurystylops glebosus4 Ameghino 1901 notoungulate
MACN A55-5, broken upper molariform
 Notoungulata - Archaeopithecidae
"Archaeopithecus alternans n. sp." = Archaeopithecus rogeri4, "Archaeopithecus rigidus n. sp." = Archaeopithecus rogeri4
"Archaeopithecus alternans n. sp." = Archaeopithecus rogeri4 Ameghino 1897 notoungulate
MACN 10815, maxilla M1-3
"Archaeopithecus rigidus n. sp." = Archaeopithecus rogeri4 Ameghino 1897 notoungulate
MACN 10813, nine specimens with 1-5 upper teeth each, including a left maxilla with P4-M2 (lectotype)
 Notoungulata - Henricosborniidae
"Polystylops progrediens n. sp." = Henricosbornia lophodonta3, "Pantostylops typus n. sp." = Henricosbornia lophodonta3, "Selenoconus centralis n. sp." = Henricosbornia lophodonta3, "Henricosbornia subconica n. sp." = Henricosbornia lophodonta1, "Selenoconus senex n. sp." = Henricosbornia lophodonta3, "Henricosbornia alouatina n. sp." = Henricosbornia lophodonta3, "Pantostylops incompletus n. sp." = Henricosbornia lophodonta3, "Polystylops amplus n. sp." = Henricosbornia ampla3, "Pantostylops minutus n. sp." = Peripantostylops minutus3, "Selenoconus agilis n. sp." = Peripantostylops minutus3, "Postpithecus reflexus n. sp." = Othnielmarshia reflexa3, "Postpithecus curvicrista n. sp." = Othnielmarshia curvicrista3, Othnielmarshia lacunifera n. gen. n. sp.3
"Polystylops progrediens n. sp." = Henricosbornia lophodonta3 Ameghino 1901 notoungulate
MACN 10708, left M3
"Pantostylops typus n. sp." = Henricosbornia lophodonta3 Ameghino 1901 notoungulate
MACN 10717, left M1 or M2 (lectotype), right M1 or M2, two broken upper molars
"Selenoconus centralis n. sp." = Henricosbornia lophodonta3 Ameghino 1901 notoungulate
MACN 10797, left m2-3 (holotype or lectotype); unassociated m3, dm4, m3
"Henricosbornia subconica n. sp." = Henricosbornia lophodonta1 Ameghino 1901 notoungulate
MACN 10809, left M3
"Selenoconus senex n. sp." = Henricosbornia lophodonta3 Ameghino 1901 notoungulate
MACN 10792, left m3 (lectotype), right m1 or m2, left m1 or m2
"Henricosbornia alouatina n. sp." = Henricosbornia lophodonta3 Ameghino 1901 notoungulate
MACN 10810, left M1 or M2
"Pantostylops incompletus n. sp." = Henricosbornia lophodonta3 Ameghino 1901 notoungulate
MACN 10707, left M3
"Polystylops amplus n. sp." = Henricosbornia ampla3 Ameghino 1904 notoungulate
MACN 10709, left M3
"Pantostylops minutus n. sp." = Peripantostylops minutus3 Ameghino 1901 notoungulate
MACN 10711, right M1 or M2
"Selenoconus agilis n. sp." = Peripantostylops minutus3 Ameghino 1901 notoungulate
MACN 10796, left dentary with m2-3 and broken m1
"Postpithecus reflexus n. sp." = Othnielmarshia reflexa3 Ameghino 1901 notoungulate
MACN 10803. "Three fragmentary lower jaws, one with m1-2, one with p4-m1, and one with p3-4. They are not associated, and the last mentioned, at least, probably does not belong to this species, or indeed family. The type description was probably based entirely on the first specimen, with m1-2, and this was also figured. It is therefore the type or lectotype."
"Postpithecus curvicrista n. sp." = Othnielmarshia curvicrista3 Ameghino 1901 notoungulate
MACN 10806. "A number of isolated teeth, not associated and perhaps not all conspecific, including isolated left m1 or m2, isolated left m3, left m1 or m2 in fragment of jaw, and right m1 or m2 in fragment of jaw. The isolated m1 or m2 and m3 were later figured (Ameghino, 1906, fig. 77), but the type description was evidently based entirely on one tooth, a m1 or m2, and the measurements given are closer to those of the isolated m1 or m2 (not in jaw fragment) in the present lot of material. This is therefore designated lectotype."
Othnielmarshia lacunifera n. gen. n. sp.3 Ameghino 1901 notoungulate
MACN 10807, complete left M1 or M2 (lectotype), broken M1 or M2, fragment of M1 or M2. May not all be conspecific.
 Notoungulata - Notostylopidae
"Notostylops aspectans n. sp." = Notostylops murinus3, "Entelostylops tripartitus n. sp." = Notostylops murinus3, "Catastylops pendens n. sp." = Notostylops pendens3
"Notostylops aspectans n. sp." = Notostylops murinus3 Ameghino 1897 notoungulate
MACN 10528, maxilla with M2-3 and broken M1, part of right dentary with broken m2
"Entelostylops tripartitus n. sp." = Notostylops murinus3 Ameghino 1897 notoungulate
MACN 10491, maxilla with parts of P3-M3
"Catastylops pendens n. sp." = Notostylops pendens3 Ameghino 1901 notoungulate
MACN 10472, crushed right maxilla with P3-M2
 Notoungulata - Notopithecidae
Antepithecus brachystephanus6, "Gonopithecus trigodontoides n. sp." = Notopithecus4, Notopithecus adapinus, "Acoelodus connectus n. sp." = Transpithecus obtentus4
Antepithecus brachystephanus6 Ameghino 1901 notoungulate
MACN-A 10827, 10842, 10857
"Gonopithecus trigodontoides n. sp." = Notopithecus4 notoungulate
MACN 10827, three right upper molars and a right upper premolar
Notopithecus adapinus Ameghino 1897 notoungulate
"Acoelodus connectus n. sp." = Transpithecus obtentus4 Ameghino 1901 notoungulate
MACN 10747, dentary fragment with m1-3
 Notoungulata - Oldfieldthomasiidae
Paginula parca n. gen. n. sp.4, "Maxschlosseria praeterita n. sp." = Maxschlosseria praeterita4, "Ultrapithecus rusticulus n. sp." = Maxschlosseria praeterita4, "Isotemnus emundatus n. sp." = Maxschlosseria praeterita4, "Oldfieldthomasia marginalis n. sp." = Maxschlosseria praeterita4, "Eochalicotherium minutum n. sp." = Maxschlosseria praeterita4, "Oldfieldthomasia septa n. sp." = Maxschlosseria praeterita4, "Maxschlosseria anatona n. sp." = Maxschlosseria praeterita4, "Antepithecus plexostephanos n. sp." = Maxschlosseria praeterita4, Oldfieldthomasia debilitata4
Paginula parca n. gen. n. sp.4 Ameghino 1901 notoungulate
MACN 10596, dentary fragment with m3 and partial m2
"Maxschlosseria praeterita n. sp." = Maxschlosseria praeterita4 Ameghino 1901 notoungulate
MACN 10624, maxilla P4-M3
"Ultrapithecus rusticulus n. sp." = Maxschlosseria praeterita4 Ameghino 1901 notoungulate
MACN 10819, maxilla P4-M3 (type or lectotype), left P4-M3, left dentary m1-3
"Isotemnus emundatus n. sp." = Maxschlosseria praeterita4 Ameghino 1901 notoungulate
MACN 10578, maxilla with P4 and broken M1-2
"Oldfieldthomasia marginalis n. sp." = Maxschlosseria praeterita4 Ameghino 1901 notoungulate
MACN 10751, maxilla P4-M2 (type), maxilla M1-2, mandible p2-m1. Other specimes under 10751 are probably not this species.
"Eochalicotherium minutum n. sp." = Maxschlosseria praeterita4 Ameghino 1901 notoungulate
MACN 10595, dentary with roots of p4 and crowns of m1-2 (type)
"Oldfieldthomasia septa n. sp." = Maxschlosseria praeterita4 Ameghino 1901 notoungulate
MACN 10758, maxilla with three teeth (type); four isolated lower teeth
"Maxschlosseria anatona n. sp." = Maxschlosseria praeterita4 Ameghino 1901 notoungulate
MACN 10617, maxilla with P4-M1 and partial M2-3
"Antepithecus plexostephanos n. sp." = Maxschlosseria praeterita4 Ameghino 1901 notoungulate
MACN 10840, a M?2 (type or lectotype); ?dP4, partial upper molars under the same number may not be this species
Oldfieldthomasia debilitata4 Ameghino 1901 notoungulate
MACN 10744, dentary m2-3
 Notoungulata - Archaeohyracidae
Eohyrax rusticus n. sp.4 Ameghino 1901 notoungulate
MACN 10775, five jaw fragments: p4-m2 (lectotype), m1-2, M1-3, P1-M2, M1-2
 Notoungulata - Isotemnidae
Thomashuxleya externa, "Coelostylops crassus n. sp." = Pleurostylodon similis4, "Dialophus recticrista n. sp." = Pleurostylodon recticrista4, Isotemnus consummatus n. sp.4, "Isotemnus latidens" = Isotemnus latidens, "Isotemnus enecatus n. sp." = Isotemnus latidens4, "Isotemnus apicatus n. sp." = Isotemnus latidens4, "Eochalicotherium crassidens n. sp." = Isotemnus latidens4, "Eochalicotherium robustum n. sp." = Isotemnus latidens4, Isotemnus primitivus4, "Anisotemnus distentus" = Anisotemnus distentus, "Isotemnus lophiodontoides n. sp." = Anisotemnus distentus4
Thomashuxleya externa Ameghino 1901 notoungulate
"Coelostylops crassus n. sp." = Pleurostylodon similis4 Ameghino 1901 notoungulate
MACN 10476, right M3
"Dialophus recticrista n. sp." = Pleurostylodon recticrista4 Ameghino 1904 notoungulate
MACN 10590, dentary with ?dp4 and ?m1
Isotemnus consummatus n. sp.4 notoungulate
MACN 10580, maxilla with broken P4-M3
"Isotemnus latidens" = Isotemnus latidens Ameghino 1901 notoungulate
"Isotemnus enecatus n. sp." = Isotemnus latidens4 Ameghino 1901 notoungulate
MACN 10587, maxilla P4-M3
"Isotemnus apicatus n. sp." = Isotemnus latidens4 Ameghino 1901 notoungulate
MACN 10614, maxilla P3-M2
"Eochalicotherium crassidens n. sp." = Isotemnus latidens4 Ameghino 1901 notoungulate
MACN 10601, dentary m2 and partial m1
"Eochalicotherium robustum n. sp." = Isotemnus latidens4 Ameghino 1901 notoungulate
MACN 10594, dentary m?2 (lectotype), other specimens in same lot may not be conspecific
Isotemnus primitivus4 Ameghino 1897 notoungulate
MACN 10598, dentary with m3 and partial m2, referred to _Eochalicotherium cretaceum_
"Anisotemnus distentus" = Anisotemnus distentus Ameghino 1901 notoungulate
"Isotemnus lophiodontoides n. sp." = Anisotemnus distentus4 Ameghino 1901 notoungulate
MACN 10615, broken M2 (type or lectotype), two broken P4s, three other tooth fragments
 Panameriungulata - Macraucheniidae
Amilnedwardsia brevicula n. sp.3 Ameghino 1901 placental
MACN 12011, upper molar
Ernestohaeckelia acutidens n. sp.3 Ameghino 1901 placental
MACN 10731, comprising a nearly complete upper molar (the lectotype) and four other molar fragments, some referable to other species
"Anisolambda longidens n. sp." = Victorlemoinea longidens5 Ameghino 1901 placental
Victorlemoineia labyrinthica n. sp.3 Ameghino 1901 placental
MACN 10671, P4 and a third of M1
Victorlemoineia emarginata n. sp.3 Ameghino 1901 placental
MACN 10672, nearly complete M1 and broken M2
 Panameriungulata - Proterotheriidae
Josepholeidya adunca n. sp.3 Ameghino 1901 placental
MACN 10702, left upper molar
 Panameriungulata - Didolodontidae
"Enneoconus parvidens n. sp." = Ernestokokenia nitida3, "Didolodus multicuspis" = Didolodus multicuspis3, "Nephacodus latigonus n. sp." = Didolodus multicuspis3, "Prohyracotherium medialis n. sp." = Archaeohyracotherium mediale3
"Enneoconus parvidens n. sp." = Ernestokokenia nitida3 Ameghino 1901 placental
MACN 10726, M3
"Didolodus multicuspis" = Didolodus multicuspis3 Ameghino 1897 placental
MACN 10728, right m3
"Nephacodus latigonus n. sp." = Didolodus multicuspis3 Ameghino 1897 placental
MACN 10725, m2
"Prohyracotherium medialis n. sp." = Archaeohyracotherium mediale3 Ameghino 1902 placental
MACN 10677, left upper molar
 Cingulata - Dasypodidae
"Utaetus laxus n. sp." = Utaetus buccatus3
"Utaetus laxus n. sp." = Utaetus buccatus3 Ameghino 1902 armadillo
MACN 10424, two scutes. Locality record based on Simpson (1967, ref. 57943).
Reptilia
 Loricata - Sebecidae
Sebecus sp.2 Stirton 1953 crocodilian
MACN 10872, tooth. Identified by Ameghino as a dinosaur and by Simpson as possibly something like _Florentinoameghinia_ (Simpson, 1932, ref. 42601). Later identified as _Sebecus_.