Pampa Castillo (Miocene of Chile)

Where: Aisén, Chile (46.9° S, 72.3° W: paleocoordinates 47.7° S, 66.6° W)

• coordinate estimated from map

• local area-level geographic resolution

When: Santacrucian mammal zone, Galera Formation, Burdigalian (20.4 - 16.0 Ma)

• "a thick stratigraphic sequence, locally exposed as a prominent butte... approximately 300 m. thick sequence"; unit is "an unnamed formation, possibly equivalent to the Río Zeballos Formation"; mammals are from "Nine major mammal-bearing horizons... though the sequence is fossiliferous throughout"; much material is from "the rich quarry sites at the base of the terrestrial section (level E-O)"

•McGrath et al 2020: The mammal-bearing beds have been variably Buenos Aires) and Lago Cochrane (¼ Lago Pueyrred?on; assigned to the R?ıo Zeballos (R. H. Niemeyer 1975), Santa Cruz (de la Cruz et al. 2004), Galera (J. Niemeyer et al. 1984), or Pampa Castillo (Scalabrino 2009) formations (see discussion in Flynn et al. [2002] and Folguera et al. [2018]). Pending formal naming, designation of a type section, and a published descrip- tion of the Pampa Castillo formation, we continue to refer these beds to the Galera Formation, consistent with previous work (Flynn et al. 2002). The sequence has been correlated stratigraphically and temporally to the Santa Cruz Formation in Argentina (J. Niemeyer et al. 1984; Flynn et al. 2002). Folguera et al. (2018) recently provided a U/Pb date of 18.7 ± 0.3 Ma for zir- cons from a reworked tuff about 10 m above the contact between the terrestrial fossil-bearing unit and the grada- tionally and conformably underlying marine Guadal Formation at Meseta Guadal. A U/Pb age of ?18Ma from a tuff within the fossil-bearing unit (Su?arez et al. 2015) is consistent with the known age range of the Santacrucian SALMA and Santa Cruz Formation depos- its and faunas (Flynn & Swisher 1995; Croft et al. 2004; Cuiti~no et al. 2016; and discussion below). No litopterns have been reported from the Galera Formation (Bostelmann & Buldrini 2012). The Pampa Castillo at Pampa Guadal, ?20km north-west of Pampa Castillo fauna is referred to the Santacrucian SALMA, although only the rodents (Dodson 1994; Chick et al. 2010) and palaeothentids (Flynn et al. 2002) have been described comprehensively. This study represents the first detailed assessment of the fauna’s SANUs.

•McGrath et al. 2022: Geochronological age estimates suggest that Pampa Castillo is also closer temporally to “Pinturan” faunas than either is to core Santacrucian faunas. Folguera et al. (2018) reported a U/Pb date of 18.7 +/-0.3 Ma from a reworked tuff directly below strata bearing the Pampa Castillo fauna. “Pinturan” faunas of the lmPF and Upper Fossil Zone at Gran Barranca are ~19.0–17.9 Ma (Perkins et al., 2012; Dunn et al., 2013), whereas core Santacrucian faunas are ~17.5–15.6 Ma (Cuitiño et al., 2016; Trayler et al., 2020).

• formation-level stratigraphic resolution

Environment/lithology: fluvial; sandstone and siltstone

• The fossil rodents of Pampa Castillo are indicative of a forested paleoenvironment with some open areas.
• "northward-dipping fluvial siltstones and sandstones with minor claystones and conglomerates"

Size class: macrofossils

Collection methods: surface (float),

Primary reference: J. J. Flynn, M. J. Novacek, H. E. Dodson, D. Frassinetti, M. C. McKenna, M. A. Norell, K. E. Sears, C. C. Swisher, III, and A. R. Wyss. 2002. A new fossil mammal assemblage from the southern Chilean Andes: implications for geology, geochronology, and tectonics. Journal of South American Earth Sciences 15(3):285-302 [J. Alroy/J. Alroy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 71843: authorized by John Alroy, entered by John Alroy on 14.05.2007, edited by Miranta Kouvari, Grace Varnham and Kateryn Pino

Creative Commons license: CC BY (attribution)

Taxonomic list

Mammalia
 Rodentia - Chinchillidae
Prolagostomus divisus Ameghino 1887 chinchilid
Prolagostomus profluens Ameghino 1887 chinchilid
Prolagostomus pusillus1 Ameghino 1887 chinchilid
Fossil Horizon E-2 (SGOPV 2612), Fossil Horizon 4 (SGOPV 2613), Fossil Horizon 6-7 (SGOPV 2427, 2607, 2608, 2609, 2610, 2611), and Fossil Horizon 7 (SGOPV 2599, 2600, 2601, 2602, 2603, 2604, 2605, 2606, 2614, 2615)
 Rodentia - Dinomyidae
Scleromys sp. Ameghino 1887 caviomorph
Scleromys sp.1 Ameghino 1887 caviomorph
Fossil Horizon 4: SGOPV 2704, right lower molar
Scleromys quadrangulatus1 Kramarz 2006 caviomorph
Fossil Horizon 4 (SGOPV 2699, 2700, 2702, 2703) and unknown Fossil Horizon (SGOPV 2701),
 Rodentia - Neoepiblemidae
Perimys "n. sp."1 Ameghino 1887 caviomorph
Fossil Horizon E-0 (SGOPV 2285, 2401, 2650), Fossil Horizon E-2 (SGOPV 2267, 2686), Fossil Horizon 4 (SGOPV 2646, 2647, 2648, 2649, 2684), and Fossil Horizon 7 (SGOPV 2431, 2679)
Perimys impactus Ameghino 1894 caviomorph
Perimys perpinguis Ameghino 1891 caviomorph
"Perimys erutus" = Perimys erutus1 Ameghino 1887 caviomorph
Fossil Horizon E-0 (SGOPV 2386, 2618, 2627, 2628, 2631, 2632, 2633, 2634, 2635, 2636, 2637, 2638, 2639, 2640, 2672, 2722), Fossil Horizon 1A (SGOPV 2361), Fossil Horizon E-2 (SGOPV 2616), Fossil Horizon 4 (SGOPV 2617, 2617, 2621, 2623, 2624, 2625, 2629, 2630), Fossil Horizon 7 (SGOPV 2641, 2642, 2643, 2644), “Glyptodont Glen” (SGOPV 2294, 2620, 2626), and unknown Fossil Horizon (SGOPV 2391, 2622)
"Perimys scalaris" = Perimys erutus Ameghino 1887 caviomorph
"Perimys procerus" = Perimys erutus Ameghino 1887 caviomorph
Perimys intermedius1 Kramarz 2002 caviomorph
Fossil Horizon E-0 (SGOPV 2299), Fossil Horizon 4 (SGOPV 2651, 2652, 2653), Fossil Horizon 4abc (SGOPV 2281), and Fossil Horizon 7 (SGOPV 2645, 2654)
Perimys onustus Ameghino 1887 caviomorph
Fossil Horizon E-0 (SGOPV 2421, 2673) Fossil Horizon E-2 (SGOPV 2101, 2675), Fossil Horizon 2 (SGOPV 2014), Fossil Horizon 3 (SGOPV 2030), Fossil Horizon 4 (SGOPV 2045, 2056, 2060, 2273, 2661, 2662, 2663, 2664, 2671, 2674, 2681, 2682), Fossil Horizon 5 (SGOPV 2080, 2665, 2687), Fossil Horizon 6-7 (SGOPV 2655, 2656, 2657, 2658, 2659, 2660), Fossil Horizon 7 (SGOPV 2121, 2378, 2666, 2667, 2668, 2669, 2670, 2677, 2678, 2680), “Glyptodont Glen” (SGOPV 2676), and unknown Fossil Horizon (SGOPV 2683)
 Rodentia -
Neoreomys australis Ameghino 1887 caviomorph
Fossil horizons E-0, E-2, 4, 5, 7, and 8,
 Rodentia - Eocardiidae
Schistomys erro Ameghino 1887 caviomorph
 Rodentia -
Luantus sp.1 Ameghino 1899 caviomorph
Fossil Horizon 4, SGOPV 2698, partial left p4
Luantus minor1 Pérez et al. 2010 caviomorph
Fossil Horizon 4 (SGOPV 2691, 2697) and Fossil Horizon 7 (SGOPV 2134); Galera Formation, Pampa Castillo, Chile.
cf. Eocardia sp.1 Ameghino 1887 caviomorph
Fossil Horizon 7: SGOPV 2695, partial left m2 and left m3 in mandibular fragment
cf. Eocardia excavata1 Ameghino 1891 caviomorph
Fossil Horizon 7: SGOPV 2133, left M1–2; SGOPV 2690, left m1–2; SGOPV 2692, right M3; SGOPV 2693, left M1 or 2; SGOPV 2694, right M2; and SGOPV 2696, right M1
"Eocardia perforata" = Eocardia robusta Vucetich 1984 caviomorph
Eosteiromys cf. annectens1 Ameghino 1901 caviomorph
Fossil Horizon E-0 (SGOPV 2157, 2688) and unknown level (SGOPV 2752)
Steiromys sp. Ameghino 1887 caviomorph
said to be new
Steiromys sp.1 Ameghino 1887 caviomorph
Fossil Horizon E-0 (SGOPV 2689) and Fossil Horizon 7 (SGOPV 2190)
Steiromys duplicatus Ameghino 1887 caviomorph
 Rodentia - Octodontidae
Sciamys principalis Ameghino 1887 caviomorph
 Rodentia -
Caviocricetus guenekko n. sp.3 McGrath et al. 2023 caviomorph
Fossil Horizon E-0 W. Holotype: SGOPV 2194, maxillary fragment bearing right DP4-M1
 Rodentia - Abrocomidae
"Acarechimys constans" = Ameghinomys constans3
"Acarechimys constans" = Ameghinomys constans3 Ameghino 1887 chinchilla rat
Fossil Horizon E-0 W (SGOPV 2198, 2199, 2707), Fossil Horizon 7 (SGOPV 2135, 2137, 2138, 2139, 2143, 2705) and Bangles Quarry (SGOPV 2362)
 Rodentia -
Acarechimys cf. minutissimus3 Ameghino 1887 caviomorph
Acarechimys minutus3 Patterson and Pascual 1967 caviomorph
said to be new
Spaniomys riparius Ameghino 1887 caviomorph
Dudumus berggreni n. sp.3 McGrath et al. 2023 caviomorph
Fossil Horizon 7. Holotype: SGOPV 2140, maxillary fragment bearing left M1–2
Stichomys ? sp. Ameghino 1887 caviomorph
 Rodentia - Echimyidae
Prostichomys "n. sp."3 Kramarz 2001 spiny rat
sp. nov. (unnamed). Fossil Horizon E-0 E. SGOPV 2706, left m1 or 2
 Panameriungulata - Proterotheriidae
Proterotheriidae indet.2 Ameghino 1887 placental
SGOPV 2220, 2416
cf. Thoatherium sp.2 Ameghino 1887 placental
SGOPV 2167
Thoatherium cf. minusculum2 Ameghino 1887 placental
SGOPV multiple specimens
Proterotherium sp. Ameghino 1883 placental
Picturotherium sp.2 Kramarz and Bond 2005 placental
SGOPV 2158
 Panameriungulata - Macraucheniidae
Theosodon sp.2 Ameghino 1887 placental
SGOPV 2064
Theosodon cf. gracilis Ameghino 1891 placental
 Cingulata - Propalaehoplophoridae
"Propalaeohoplophorus sp." = Propalaehoplophorus
"Propalaeohoplophorus sp." = Propalaehoplophorus Ameghino 1887 edentate
 Cingulata - Chlamyphoridae
"Prozaedius sp." = Prozaedyus, Proeutatus sp.
"Prozaedius sp." = Prozaedyus Ameghino 1891 edentate
Proeutatus sp. Ameghino 1891 edentate
 Megatherioidea - Megalonychidae
Hapalops sp. Ameghino 1887 edentate
 Notoungulata - Homalodotheriidae
Homalodotherium sp. Huxley 1870 notoungulate
 Notoungulata - Toxodontidae
Adinotherium sp. Ameghino 1887 notoungulate
Nesodon sp. Owen 1846 notoungulate
 Notoungulata - Hegetotheriidae
Hegetotherium sp. Ameghino 1887 notoungulate
 Notoungulata - Interatheriidae
Protypotherium sp. Ameghino 1882 notoungulate
 Astrapotheria - Astrapotheriidae
Astrapotherium sp. Burmeister 1879 placental
 Paucituberculata - Palaeothentidae
Palaeothentes smeti n. sp. Flynn et al. 2002 marsupial
Palaeothentes pascuali Bown and Fleagle 1993 marsupial
Palaeothentes minutus Ameghino 1887 marsupial
Palaeothentes intermedius Ameghino 1887 marsupial
 Sparassodonta -
Cladosictis sp. Ameghino 1887 metatherian