PBDB Collection

Los Alamitos vertebrates, middle section (Cretaceous to of Argentina)

Also known as Los Alamitos vertebrates, middle section - green-coloured bed (mammals), Cerro Cuadrado, Arroyo Verde

Where: Río Negro, Argentina (42.1° S, 66.3° W: paleocoordinates 45.0° S, 52.3° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Los Alamitos Formation, Late/Upper Campanian to Late/Upper Campanian (83.5 - 66.0 Ma)

• middle section of formation includes vertebrate fossils distributed over about 30 meters of section

•Mammals: Middle section of Los Alamitos Formation - green-coloured bed just below the concretionary top of the Cerrito del Mamifero, Alamitian provincial age (Campanian sensu lato)

• group of beds-level stratigraphic resolution

Environment/lithology: lacustrine - large; bioturbated, concretionary, yellow siltstone and bioturbated, intraclastic sandstone

• dominant environment lacustrine, more brackish than fresh (clay flocculation in pelites). waters were oxygenated; lake permanent and shallow.

•The paleoenvironment according to Andreis (1987; and personnal communication) is that of a lacustrine environment mixed with shallow marine sediments, as indicated by the presnce of glauconite in some levels of the sequence.

• "Pelitic facies: includes dominant massive, laminated or rippled (rare) siltstones and claystones, with yellowish (lower part of the sequences) to reddish, orange, brown and purple hues (upper part), and massive sandstones. This rocks show typical paquidermis solution pattern which allow its recognition in outcrops. The non-calcareous pelites contains (lower half) almost all the vertebrate remains"

Size classes: macrofossils, mesofossils

Preservation: trace

Collected by J. F. Bonaparte, J. E. Powell in 1982-1983

Collection methods: quarrying, surface (float), surface (in situ), mechanical,

Primary reference: J. F. Bonaparte. 1984. Nuevas pruebas de la conexion fisica entre Sudamerica y Norteamerica en el Cretácico Tardio (Campaniano) [New evidences for the physical connection between South and North America in the Late Cretaceous (Campanian)]. Actas del III Congreso Argentino de Paleontologia y Bioestratigrafia 1:141-149 [M. Carrano/M. Carrano/M. Carrano]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 45087: authorized by Matthew Carrano, entered by Matthew Carrano on 04.10.2004, edited by Franco Aspromonte, Philip Mannion, Roger Benson, Jonathan Tennant and Evangelos Vlachos

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names

Chondrichthyes
Euselachiformes -	Batoidei indet.¹² Batoidei indet.¹² elasmobranch MACN-RN 148, twelve vertebrae
Actinopteri
Lepisosteiformes - Lepisosteidae	Lepisosteidae indet.¹², cf. Atractosteus sp.¹² Lepisosteidae indet.¹² Cuvier 1825 gar MACN-RN 150, 156, six vertebrae, skulls fragments and 200 dermal scales cf. Atractosteus sp.¹² Rafinesque 1820 gar MACN-RN 149, three teeth
Teleostei -	Siluriformes indet.¹² Siluriformes indet.¹² catfish MACN-RN 154, 1139-1140, spines
Siluriformes - Diplomystidae	cf. Diplomystidae indet.¹² cf. Diplomystidae indet.¹² Eigenman 1890 catfish MACN-RN 152, eight proximal fragments, eight central fragments and one pectoral spine
Siluriformes - Ariidae	cf. Ariidae indet.¹² cf. Ariidae indet.¹² Berg 1958 Ariid catfish MACN-RN 153, three pectoral spines fragments
Spariformes - Sparidae	Sparidae indet.¹² Sparidae indet.¹² Cuvier 1817 "Lepidotes or Sparidae"
Perciformes -	Percoidei indet.¹² Percoidei indet.¹² Bleeker 1859 perch-like fish MACN-RN 155, tooth
Osteichthyes
Dipnoi - Ceratodontidae	Atlantoceratodus patagonicus¹, "Ceratodus iheringi" = Atlantoceratodus iheringi¹², Metaceratodus wichmanni n. sp.¹³ Atlantoceratodus patagonicus¹ Agnolín 2010 lungfish MACN PV RN157C, right lower tooth plate "Ceratodus iheringi" = Atlantoceratodus iheringi¹² Ameghino 1906 lungfish MACN-RN 157-158, dental plates Metaceratodus wichmanni n. sp.¹³ Apesteguía and Agnolin 2007 lungfish MACN PV RN157A, left upper tooth plate
Dipnoi - Ptychoceratodontidae	Ptychoceratodus cionei n. sp.⁵ Ptychoceratodus cionei n. sp.⁵ Apesteguia et al. 2007 lungfish MACN PV RN157A and 157B, two lower tooth plates
Mammalia
Allotheria - Sudamericidae	Gondwanatherium patagonicum n. gen. n. sp.⁶ Gondwanatherium patagonicum n. gen. n. sp.⁶ Bonaparte 1986 mammal MACN-RN 22 (holotype) 22-26, 228, 703-705, 970, 1024-1031
Allotheria -	Ferugliotherium sp.¹⁷, Ferugliotherium windhauseni n. gen. n. sp.⁷ Ferugliotherium sp.¹⁷ Bonaparte 1986 mammal MACN-RN 249 (anterior upper premolar), and framgnetary left dentary Ferugliotherium windhauseni n. gen. n. sp.⁷ Bonaparte 1986 mammal MACN-RN 20 (holotype worn right m2) and specimen referred by Krause et al 1992: MACN-RN 701A, B (partial left i1s), 701C (partial i1), 253 (partial left m1), 702A–D (partial I2s), 248-251, MACN-RN 975; incisors and premolars only tentatively referred
Dryolestoidea -	Meridiolestida indet.¹⁵ Meridiolestida indet.¹⁵ Rougier et al. 2011 mammal MACNPV-RN241, complete right upper premolariform
Meridiolestida -	Austrotriconodon mckennai n. gen. n. sp.⁷ Austrotriconodon mckennai n. gen. n. sp.⁷ Bonaparte 1986 mammal MACN-RN 21 (holotype) 234-238
Meridiolestida - Mesungulatidae	Mesungulatidae indet.¹⁵, Mesungulatum houssayi n. gen. n. sp.⁸ Mesungulatidae indet.¹⁵ Bonaparte 1986 mammal MACN-RN 239, complete left P1; MACN-RN 240, complete left p1, MACN-RN 1135-1137 Mesungulatum houssayi n. gen. n. sp.⁸ Bonaparte and Soria 1985 mammal MACN-RN 1, 3-12, 141, 181-184, 244
Dryolestoidea - Dryolestidae	Groebertherium indet.²⁰, Groebertherium novasi n. gen. n. sp.⁷, Groebertherium stipanicici n. gen. n. sp.⁷ Groebertherium indet.²⁰ Bonaparte 1986 mammal MACN-RN 185-200 Groebertherium novasi n. gen. n. sp.⁷ Bonaparte 1986 mammal MACN-RN 18-19 Groebertherium stipanicici n. gen. n. sp.⁷ Bonaparte 1986 mammal MACN-RN 13-17
Dryolestida - Casamiquelidae	Alamitherium bishopi n. gen. n. sp.⁹, Rougietherium tricuspes n. gen. n. sp.⁹ Alamitherium bishopi n. gen. n. sp.⁹ Bonaparte 2002 mammal MACN-RN 1034-1036 Rougietherium tricuspes n. gen. n. sp.⁹ Bonaparte 2002 mammal MACN-RN 162
Dryolestida -	Paraungulatum rectangularis n. gen. n. sp.⁹ Paraungulatum rectangularis n. gen. n. sp.⁹ Bonaparte 2002 mammal MACN-RN 180 (left upper molar), 1141
Paratheria -	Paratheria indet.⁸ Paratheria indet.⁸ Thomas 1887 mammal
Reptilia
Ornithischia - Hadrosauridae	"Kritosaurus australis n. sp." = Huallasaurus australis¹⁰ "Kritosaurus australis n. sp." = Huallasaurus australis¹⁰ Bonaparte et al. 1984 hadrosaurine MACN-RN 142-146, 826, 977-995, 997-998
Saurischia - Titanosauridae	Titanosauridae indet.²¹, Titanosauridae indet.¹⁶ Titanosauridae indet.²¹ Lydekker 1885 titanosaurid MACN-RN 1102, 1128 Titanosauridae indet.¹⁶ Lydekker 1885 titanosaurid MACN-RN 147
Theropoda -	Ornithothoraces indet.¹¹, Ornithurae indet.² Ornithothoraces indet.¹¹ Chiappe and Calvo 1994 avialan MACN-RN 976 (partial cervical vertebra) Ornithurae indet.² avialan MACN PV RN 1111 (distal end of left tibiotarsus, without distal condyles), MACN PV RN 1112 (distal end of left tibiotarsus with damaged medial condyle) and MACN PV RN 1113 (distal end of left tibiotarsus with complete distal condyles)
Ornithurae -	cf. Hesperornithiformes indet.² cf. Hesperornithiformes indet.² Fürbringer 1888 avialan MACN PV RN 1114 (distal end of left tibia)
Theropoda -	Alamitornis minutus n. gen. n. sp.² Alamitornis minutus n. gen. n. sp.² Agnolin and Martinelli 2009 avialan MACN PV RN 1108 - holotype (proximal third of a left humerus) and referred material: MACN PV RN 1109 (five proximal extremes of right humeri of different individuals) and MACN PV RN 1110 (distal half of a left femur of a juvenile specimen)
Aves
Aves -	Aves indet.² Aves indet.² bird MACN PV RN 1103 (distal end of indeterminate pedal phalanx), MACN PV RN 1104 (distal end of pedal phalanx, probably II-2), MACN PV RN 1105 (pedal ungual of digit I) and MACN PV RN 1106 (manual ungual of digit I); MACN PV RN 1107 (pedal phalanx 1 of right digit II without its proximal end)
Neornithes -	cf. Neornithes indet.² cf. Neornithes indet.² bird MACN PV RN 1115 (distal end of right tarsometatarsus without metatarsal IV and distal trochlea of metatarsal II)
Reptilia
Eosuchia - Sphenodontidae	Sphenodontidae indet.⁴, Kawasphenodon expectatus n. gen. n. sp.⁴ Sphenodontidae indet.⁴ Cope 1871 lepidosaur MACN Pv RN1099c, 1100 Kawasphenodon expectatus n. gen. n. sp.⁴ Apesteguía 2005 lepidosaur MACN Pv RN1098, 1099a-b
Testudines - Chelidae	Chelidae "indet. D"¹⁴, aff. Emydura sp.¹⁹, cf. Yaminuechelys sp.¹⁹ Chelidae "indet. D"¹⁴ Gray 1825 sideneck turtle The abundance is estimated, should be checked. MACN-RN 43-64, 77-100, 102-140 aff. Emydura sp.¹⁹ Bonaparte 1836 sideneck turtle The abundance is estimated, should be checked. MACN-RN 43-64, 77-100, 102-140 cf. Yaminuechelys sp.¹⁹ de la Fuente et al. 2001 sideneck turtle The abundance is estimated, should be checked. MACN-RN 43-64, 77-100, 102-140
Testudines - Panchelidae	Palaeophrynops patagonicus n. gen. n. sp.¹⁸ Palaeophrynops patagonicus n. gen. n. sp.¹⁸ Lapparent de Broin and de la Fuente 2001 sideneck turtle
Testudinata -	Meiolaniformes indet.²² Meiolaniformes indet.²² Sterli and de la Fuente 2013 turtle MACN-RN 36-42, 65-76, 101
Squamata - Madtsoiidae	"Madtsoiinae indet." = Madtsoiidae²⁰, Alamitophis argentinus n. gen. n. sp.³, Rionegrophis madtsoioides n. gen. n. sp.³, Patagoniophis parvus n. gen. n. sp.³ "Madtsoiinae indet." = Madtsoiidae²⁰ Hoffstetter 1961 snake MACN-RN 201-202, 204-227 Alamitophis argentinus n. gen. n. sp.³ Albino 1986 snake MACN-RN 27 (holotype) 27–31, 203 Rionegrophis madtsoioides n. gen. n. sp.³ Albino 1986 snake MACN-RN 32 Patagoniophis parvus n. gen. n. sp.³ Albino 1986 snake MACN-RN 33-35
Amphibia
Salientia - Pipidae	Kuruleufenia xenopoides²³ Kuruleufenia xenopoides²³ Gómez 2016 clawed frog
Salientia - Calyptocephalellidae	Calyptocephalellidae indet.²³ Calyptocephalellidae indet.²³ Reig 1960 frog

¹Agnolín 2010; ²Agnolin and Martinelli 2009; ³Albino 1986; ⁴Apesteguía 2005; ⁵Apesteguia et al. 2007; ⁶Bonaparte 1986; ⁷Bonaparte 1986; ⁸Bonaparte 1987; ⁹Bonaparte 2002; ¹⁰Bonaparte et al. 1984; ¹¹Chiappe 1996; ¹²Cione 1987; ¹³Cione and Gouiric-Cavalli 2012; ¹⁴de Broin 1987; ¹⁵Gaetano et al. 2013; ¹⁶Juárez Valieri and Calvo 2011; ¹⁷Kielan-Jaworowska et al. 2004; ¹⁸Lapparent de Broin and de la Fuente 2001; ¹⁹Maniel 2015; ²⁰Pol et al. 2023; ²¹Powell 1987; ²²Sterli et al. 2013; ²³Suazo Lara and Gómez 2022