La Barda, Paso del Sapo (Eocene of Argentina)

Also known as Bardalestes hunco type - Estancia 26 de Mayo

Where: Chubut, Argentina (42.8° S, 69.9° W: paleocoordinates 45.3° S, 60.1° W)

• coordinate stated in text

• small collection-level geographic resolution

When: Andesitas Huancache Formation, Lutetian (47.8 - 41.3 Ma)

• These include a fauna from the Tufolitas Laguna del Hunco Formation

•at Laguna Fría (42° 43’ 31.5” S, 69° 51’ 36.1” W) and another from the interbedded tuffs of the

•Andesitas Huancache Formation at the La Barda locality (42° 46’ 48.5” S, 69° 51’ 43.3”) (Fig. 1). The

•age of these faunas is constrained by radioisotopic dates from nearby volcanic deposits which underlie

•and overlie the mammal-bearing levels. The Laguna Fría fauna unconformably overlies a basal

•ignimbrite dated by 40Ar-39Ar method at 49.51 ± 0.32 and it underlies the Andesitas Huancache alkaline

•basalt dated at 47.89 ± 1.21 Ma (Tejedor et al., 2009). At the second locality, the La Barda Tuffs are

•interbedded with the Andesitas Huancache lava flows, and they occur above a basalt dated by the 40K40Ar method to 47.89 ± 1.21 Ma (Tejedor et al., 2009). This indicates that the Paso del Sapo faunas are

•late early Eocene in age (Ypresian-Lutetian boundary).

• bed-level stratigraphic resolution

Environment/lithology: fluvial; tuff

• Lorente et al 2016: Mammal-bearing levels at the La Barda locality occur within the Andesitas Huancanche interbedded tuffs. The Andesitas Huancanche are part of the so-called Middle Chubut River Volcanic–Pyroclastic Complex, the geology and stratigraphy of which was reviewed by Arag?on & Mazzoni (1997). Additional information on the regional geology, stratigraphy, geochemistry, petrogenesis and palaeobotany of this complex has been provided by Peter- sen (1946), Archangelsky (1974), Volkheimer & Lage (1981), Lage (1982), Rapela et al. (1984), Arag?on & Romero (1984), Arag?on et al. (1987), Mazzoni & Arag?on (1985) and Mazzoni et al. (1989). The Andesitas Huan- cache Upper Member comprises alkali basalts dated of these levels between 45 and 47 Ma was proposed by between 47.89 ? 1.21and 43 Ma. A time of deposition Tejedor et al. (2009).

Size class: mesofossils

Collected in 2005–2010

Collection methods: bulk, surface (float), sieve,

Primary reference: F. J. Goin, A. M. Candela, M. A. Abello and E. V. Oliveira. 2009. Earliest South American paucituberculatans and their significance in the understanding of ‘pseudodiprotodont’ marsupial radiations. Zoological Journal of the Linnean Society 155:867-884 [P. Mannion/P. Mannion]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 133039: authorized by Philip Mannion, entered by Philip Mannion on 31.08.2012, edited by Matthew Carrano, Jelle Zijlstra and Miranta Kouvari

Creative Commons license: CC BY (attribution)

Taxonomic list

Mammalia
 Cingulata - Dasypodidae
Prostegotherium cf. astrifer4 Ameghino 1902 armadillo
osteoderms
Riostegotherium sp.4 Oliveira and Bergqvist 1998 armadillo
Several isolated plates of the dorsal carapace
Stegosimpsonia sp.4 Vizcaino 1994 armadillo
several isolated plates of the dorsal carapace
 Notoungulata - Notostylopidae
Notostylops sp.4 Ameghino 1897 notoungulate
Mandibular fragments and isolated upper teeth that can be referred to the genus Notostylops are abundant in both localities of Paso del Sapo
Homalostylops parvus4 Ameghino 1897 notoungulate
mandibular fragment with m1–2 of a small notostylopid was collected in La Barda (LIEB-PV 1621).
 Notoungulata - Henricosborniidae
Henricosbornia lophodonta4 Ameghino 1901 notoungulate
"Maxillary and mandibular fragments re- ferred to the Family Henricosborniidae are abundant in both localities of Paso del Sapo, with complete series of premolars and molars, as well as isolated teeth."
 Notoungulata - Archaeopithecidae
Archaeopithecus cf. rogeri4 Ameghino 1897 notoungulate
Not clear which material comes from Laguna Fría and which from La Barda. "Several maxillary and mandibular fragments (e.g., LIEB-PV 1625 to 1628), as well as isolated teeth (e.g., LIEB-PV 1629) referred to this family have been found in La Barda and Laguna Fría."
 Panameriungulata - Protolipternidae
Asmithwoodwardia "sp. nov."4 Ameghino 1901 placental
m1 or m2 (LIEB-PV 1613)
Asmithwoodwardia subtrigona4 Ameghino 1901 placental
 Theriamorpha -
Marmosopsis sp.4 Paula Couto 1962 metatherian
two right mx (LIEB-PV 1286, and LIEB-PV 1287)
Palangania sp.4 Goin et al. 1998 marsupial
LIEB-PV 1106, left M?3; fig. 3J
Palangania cf. brandmayri4 Goin et al. 1998 marsupial
Two lower molars from La Barda (LIEB- PV 1089 and 1090)
 Theriamorpha - Peradectidae
"Caroloameghiniidae "gen. et sp. nov. 2"" = Caroloameghiniinae4, "? Caroloameghiniidae indet." = Caroloameghiniinae4
"Caroloameghiniidae "gen. et sp. nov. 2"" = Caroloameghiniinae4 Ameghino 1901 marsupial
one upper molar from La Barda (LIEB-PV 1098, a left MX)
"? Caroloameghiniidae indet." = Caroloameghiniinae4 Ameghino 1901 marsupial
isolated, left mx talonid (LIEB- PV 1099)
 Theriamorpha -
Australidelphia indet.3 Szalay 1982 marsupial
one astragalus and three calcanea
 Marsupialia -
? Microbiotheria "gen. et sp. indet. F"4 Ameghino 1899 marsupial
two upper molars
 Microbiotheria - Microbiotheriidae
? Microbiotheriidae "gen. et sp. indet. E"4 Ameghino 1887 marsupial
LIEB-PV 1094 is an upper right molar lacking the protocone, probably an M4
 Marsupialia -
Didelphimorphia "gen. et sp. nov. 3"4 Gill 1872 marsupial
Several upper and lower molars
 Theriamorpha - Protodidelphidae
Protodidelphis "sp. nov."4 Paula Couto 1952 marsupial
several lower and upper isolated teeth, including LIEB-PV 1097, left M3
Protodidelphis sp.4 Paula Couto 1952 marsupial
Two isolated lower molars (LIEB-PV 1092, isolated left m?1; LIEB-PV 1142, isolated left m?3)
 Theriamorpha - Derorhynchidae
Pauladelphys sp.4 Goin et al. 1999 marsupial
a few specimens
 Marsupialia -
Paucituberculata "gen. et sp. nov. 5"4 Ameghino 1894 marsupial
one upper (LIEB-PV 1151) and three lower molars (LIEB-PV 1101, 1136)
? Paucituberculata "gen. et sp. indet. B"4 Ameghino 1894 marsupial
left mandible
 Paucituberculata -
Bardalestes hunco n. gen. n. sp.
Bardalestes hunco n. gen. n. sp. Goin et al. 2009 marsupial
LIEB-PV 1135 - holotype (a fragment of left maxillary with M2–3, and roots and part of the crown of M4)
 Theriamorpha -
Gashternia ctalehor4 Simpson 1935 marsupial
Several upper and lower molars
 Sparassodonta - Borhyaenidae
Borhyaeninae "gen. et sp. indet. C"4 Ameghino 1894 metatherian
LIEB-PV 1093 is a right m?1
 Sparassodonta - Hathliacynidae
"Hathliacynidae "gen. et sp. nov. 6"" = Hathlyacininae4
"Hathliacynidae "gen. et sp. nov. 6"" = Hathlyacininae4 Ameghino 1894 metatherian
LIEB-PV 1141, a fragment of a left M?2
 Polydolopimorphia - Polydolopidae
Polydolopidae indet.1 Ameghino 1897 metatherian
LIEB-PV 1178 is a right mandibular fragment with p3–m1
Amphidolops "sp. nov. 2"4 Ameghino 1902 metatherian
Not clear which material comes from Laguna Fría and which from La Barda. "LIEB-PV 1187, a right m2, and several isolated lower and upper molars from both localities of Paso del Sapo"
Amphidolops intermedius n. sp.1 Chornogubsky 2020 metatherian
type: LIEB-PV 1187, LIEB-PV 1188, LIEB-PV 1181, LIEB-PV 1182, LIEB-PV 1183, LIEB-PV 1184, LIEB-PV 1185 and LIEB-PV 1186
Hypodolops sapoensis1 Chornogubsky 2020 metatherian
Not clear which material comes from Laguna Fría and which from La Barda. "LIEB-PV 1153, a maxillary fragment with M1–2, as well as four lower molars are included in this new species recovered in La Barda and Laguna Fría"
Hypodolops sapoensis1 Chornogubsky 2020 metatherian
Not clear which material comes from Laguna Fría and which from La Barda. "LIEB-PV 1173, a right maxillary fragment with M1–2, as well as several maxillary and mandibular remains and isolated teeth have been assigned to this new taxon collected in both localities of Paso del Sapo."
Polydolops unicus n. sp.4 Tejedor et al. 2009 metatherian
Holotype, LIEB-PV 1252, right maxillary fragment with P3–M3; LIEB-PV 1245, left maxillary fragment with M1–2; LIEB-PV 1246, left M1; LIEB-PV 1247, left M2; LIEB-PV 1248, left M2; LIEB-PV 1249, left M2; LIEB-PV 1250, left M2; LIEB-PV 1251, right maxillary fragment with P3–M3; LIEB-PV 1253, right M1; LIEB-PV 1254, right M1; LIEB-PV 1255, right M1; LIEB- PV 1256, right, broken M2; LIEB-PV 1257, right M3; LIEB-PV 1258, right M3; LIEB-PV 1263, left mandible with m1–2; LIEB-PV 1265, left m2; LIEB-PV 1266, left, broken m2; LIEB-PV 1267, right mandible with broken p3, complete m1–2, and roots of m3; LIEB-PV 1268, right mandible with m2; LIEB-PV 1269, right mandible with m2; LIEB-PV 1270, right mandible with m2; LIEB-PV 1271, right mandible with broken m1, complete m2, and roots of m3; LIEB-PV 1272, left m1; LIEB-PV 1273, right m1; LIEB-PV 1274, right m1; LIEB-PV 1275, right m2; LIEB-PV 1276, broken right m2; LIEB-PV 1277, right m3; LIEB-PV 1278, right m3.
"Polydolops rothi" = Pliodolops rothi4 Simpson 1936 metatherian
several upper and lower specimens
 Allotheria - Sudamericidae
Greniodon sylvaticus n. gen. n. sp.2
Greniodon sylvaticus n. gen. n. sp.2 Goin et al. 2012 mammal
LIEB-PV 2000, 2001