The Salamanca Formation is a geologic formation in the Golfo San Jorge Basin of central Patagonia that yields well-preserved, well-dated fossils from the early Paleocene. Studies of these fossils are providing new data on plant and animal diversity following the end-Cretaceous extinction event. Material was copied from this source, which is available under a Creative Commons Attribution 4.0 International License
The Salamanca Formation crops out in the San Jorge Basin in southern Chubut and northern Santa Cruz provinces, Argentina, overlying the Cretaceous Chubut Group and is part of the Paleocene and Eocene Río Chico Group. The formation yields abundant plant remains as well as fossils of invertebrates, marine macrofaunas, reptiles, and mammals. The formation consists primarily of estuarine to shallow marine deposits.
Palynological analysis of the Salamanca Formation shows low floral diversity after the end-Cretaceous mass extinction, followed by a rapid recovery. 50% of all pollen types are angiosperms, whereas gymnosperms accounted for only ~13% of total richness; however, Classopollis pollen, representing the extinct conifer family Cheirolepidiaceae, is the most abundant palynomorph. Wood assemblages from the Salamanca Formation are dominated by conifers, but the presence of fossil angiosperm woods indicate that they were also part of the canopy. The co-occurrence of palms, dicot woods with indistinct growth rings, and alligatorids, indicates temperature remained above freezing year-round. The results of leaf physiognomic analyses indicate that the climate in the San Jorge Basin during the early Paleocene was warm subtropical.
Paleoflora Angiosperm Name Species Locality Material Notes ImageAkaniaA. sp.Palacio de los LorosA flowering plant of the family AkaniaceaeBanaraphyllumB. ovatumPalacio de los LorosA flowering plantCissitesC. patagonicumPalacio de los LorosA flowering plant belonging to Vitaceae, related to the modern genus CissusCunonianthaC. bicarpellataA flowering plant belonging to the family CunoniaceaeDryophyllumD. australisPalacio de los LorosA flowering plantFagophyllumF. duseniPalacio de los LorosLeaves, related to FagaceaeLacinipetalumL. spectabilumPalacio de los LorosA flowering plant belonging to the family CunoniaceaeLaurophyllumL. chubutensis L. piatnitzkyiPalacio de los LorosA flowering plant belonging to the family LauraceaeMyricaM. premiraPalacio de los LorosA flowering plant belonging to the family MyricaceaeNothofagussp.LeavesNotianthaN. grandensisRancho GrandeFlowersA flowering plant belonging to the family RhamnaceaePalaeophytocreneP. gaEstancia Las VioletasA fruitA flowering plant belonging to the family IcacinaceaeParacacioxylonP frenguelliiPalacio de los LorosWoodA flowering plant belonging to the family MimosoideaeParanymphaeaP aristolochiaformisPalacio de los LorosA flowering plant belonging to the family NymphaeaceaeSterculiaS. acuminatalobaPalacio de los LorosA flowering plant belonging to the family MalvaceaeStephaniaS. psittacaPalacio de los LorosA flowering plant belonging to the family MenispermaceaeSuesseniaS. grandensisRancho GrandeLeavesA flowering plant belonging to the family RhamnaceaeWilkinsoniphyllum W. menispermoides Palacio de los LorosLeavesA flowering plant belonging to the family MenispermaceaeTripylocarpaT. aestuariaSeedA flowering plant belonging to the palm tribe Cocoseae VolkheimeritesV. labyrinthusFlowering plant pollen of uncertain placementFabaceaeSapindaceaeUrticaceaeRosaceae
Gymnosperms Name Species Locality Material Notes ImageAgathisA. immortalisLeaves, twigs, pollen cones, ovuliferous complexes, pollen, seedsA conifer belonging to Araucariaceae. Oldest known species of AgathisClassopollisC. sp.Palacio de los LorosPollen belonging to the extinct conifer family CheirolepidiaceaePodocarpaceaeLeaves and cones
Ferns
Name Species Locality Material Notes ImageAzollaA. keujaPalacio de los LorosA fern belonging to the family SalviniaceaeKirketapelK. salamanquensisA scale-leaved conifer belonging to the family Podocarpaceae.LygodiumSp.A fern belonging to the Schizaeales, another indeterminate distinct fern is also present
Paleofauna Fish Name Species Locality Material Notes ImageXiphactinusX. sp.A member of the Ichthyodectiformes.
Amphibians Name Species Locality Material Notes ImageGigantobatrachusG. casamiquelaiPunta PeligroA frogXerocephalellaX. sabrosaPunta PeligroA frog belonging to the family Calyptocephalellidae.
Reptiles Testudines Name Species Locality Material Notes ImageHydromedusaH. casamayorensisPunta PeligroA member of the family Chelidae.NajadochelysN. patagonicaPunta PeligroPeligrochelysP. walshaePunta PeligroA member of MeiolaniformesSalamanchelysS. palaeocenicaPunta PeligroA member of the family Chelidae.TrionyxT. argentinaPunta PeligroA member of the family TrionychidaeYaminuechelysY. maiorPunta PeligroA member of the family Chelidae.
Crocodylomorphs Name Species Locality Material Notes ImageEocaimanE. palaeocenicusPunta PeligroA caimanine alligatorid. NecrosuchusN. ionensisEstancia Las VioletasA caimanine alligatorid.ProtocaimanP. peligrensisPunta Peligro A partial skullA caimanine alligatorid.TewkensuchusT. salamanquensisPunta Peligro A holotype specimen consists of a partial skullA sebecosuchian
Lepidosaurs Name Species Locality Material Notes ImageKawasphenodonK. peligrensisPunta PeligroA sphenodontian
Mammals
Monotremes Name Species Locality Material Notes ImageMonotrematumR. Pascual, M. Archer, E. O. Jaureguizar, J. L. Prado, H. Godthelp and S. J. Hand. 1992. The first non-Australian monotreme: an early Paleocene South American platypus (Monotremata, Ornithorhynchidae). Platypus and Echidnas. Royal Zoological Society of New South Wales 1-14M. sudamericanumPunta PeligroTeeth from the upper and lower jawsA monotreme
Allotheres Name Species Locality Material Notes ImageSudamericaS. ameghinoiPunta PeligroA gondwanathere
Meridiolestidans Name Species Locality Material Notes ImagePeligrotheriumP. tropicalisPunta PeligroA member of the clade Mesungulatoidea.
Meridiungulates Name Species Locality Material Notes ImageEscribaniaE. chubutensis E. talonicuspsisPunta PeligroA member of the family Didolodontidae.RaulvacciaR. peligrensisPunta PeligroA member of the family Didolodontidae.RequisiaR. vidmariPunta PeligroA member of the family Notonychopidae.
Metatherians Name SpeciesLocality Material Notes ImageDerorhynchusD. aff. minutusPunta PeligroA metatherian of uncertain affinitiesDidelphopsisIndeterminate?SparassodontaIndeterminateAstragalusPolydolopimorphiaIndeterminateTwo taxa, one of which is a member of Bonapartheriidae MetatheriaIndeterminateRight petrosal (MPEF-PV 2235)
Invertebrates After unless otherwise noted
Name Species Material Notes ImageAcestaA bivalve belonging to LimidaeArcaA bivalve belonging to Arcidae?AstarteA bivalve belonging to AstartidaeAporrhaidaeIndeterminateGastropodAustrophaeraA bivalveBarbatiaA bivalve belonging to ArcidaeBathytormusA bivalve belonging to Crassatellidae BuccinidaeFour distinct generaGastropodCancellariidaeIndeterminateA gastropodCalyptraeidaeIndeterminateGastropodCarditesA bivalve belonging to CarditidaeCavoscalaA gastropod belonging to EpitoniidaeClaibornicardiaA bivalve belonging to CarditidaeCostacoplumaC. salamancaA crab belonging to the family RetroplumidaeCrenilabiumA gastropod belonging to Acteonidae CubitostreaA bivalve belonging to OstreidaeCucullaeaBivalveDarwinicesA gastropod belonging to Naticidae?DosiniaA bivalve belonging to VeneridaeFusinusA gastropod belonging to FasciolariidaeFyfeaA gastropodGlobisininaeIndeterminateGastropods belonging to the family NaticidaeGlycymeritaA bivalve belonging to Glycymerididae GryphaostreaA bivalveGyroscalaA gastropod belonging to EpitoniidaeHarpidaeNov. Gen.A gastropodHeterotermaA gastropod belonging to Tudiclidae?LarmaA bivalve belonging to Veneridae LedinaA bivalve belonging to NuculanidaeLeionuculaA bivalve belonging to NuculidaeLucinidaeIndeterminateBivalveMarwickiaA bivalve belonging to VeneridaeMicrofulgurA gastropod belonging to Fasciolariidae NeiloA bivalve belonging to MalletiidaeNuculaA bivalve belonging to NuculidaePanopeaA bivalve belonging to HiatellidaePatellogastropodaIndeterminateGastropodPerissodontaA gastropod belonging to StruthiolariidaePhacoidesA bivalve belonging to LucinidaePinnaA bivalve belonging to PinnidaePriscaphanderA gastropod belonging to ScaphandridaePriscophicusA gastropod belonging to FicidaePseudomauraA gastropodPteromyrteaA bivalve belonging to LucinidaePseudotylostomaA gastropodPycnodonteA bivalve belonging to GryphaeidaeRingiculidaeIndeterminateA gastropodRocalariaA gastropod belonging to FasciolariidaeRotundicardiaA bivalve belonging to CarditidaeSacellaA bivalve belonging to NuculanidaeSpineiloA bivalve belonging to MalletiidaeStruthiopteraA gastropod belonging to AporrhaidaeSulcobuccinumA gastropod belonging to Pseudolividae TaiomaA gastropod belonging to FasciolariidaeTalochlamysA bivalve belonging to PectinidaeTejoniaA gastropod belonging to NaticidaeTitomayaT. longobucca & T. chalcedonica A bivalve belonging to VeneridaTornatellaeaA gastropod belonging to ActeonidaeTurritellidaeNov. gen.A gastropodVenericardiaA bivalve belonging to CarditidaeVolutidaeIndeterminateGastropodYoldiaA bivalve belonging to Yoldiidae?ZemaciesA gastropod belonging to Borsoniidae
References