El Rosario: Late/Upper Turonian - Early/Lower Coniacian, Mexico
List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
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Granuloreticulosea
- Foraminiferida
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Whiteinella sp.
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foram |
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unclassified
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Plantae indet.
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| Fossil wood | ||||||||||
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Granuloreticulosea
- Foraminiferida
- Globotruncanidae
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Marginotruncana sp.
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foram |
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Dicarinella sp.
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foram |
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Granuloreticulosea
- Foraminiferida
- Heterohelicidae
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Heterohelix sp.
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foram |
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Cirripedia
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Stramentum sp.
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barnacle |
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Malacostraca
- Decapoda
- Callianassidae
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cf. Callianassa sp.
Leach 1814
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decapod |
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Malacostraca
- Decapoda
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Brachyura indet.
Latreille 1802
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crab |
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| New family | ||||||||||
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Cephalopoda
- Ammonoidea
- Gaudryceratidae
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Gaudryceras mite
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ammonite |
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Cephalopoda
- Ammonoidea
- Collignoniceratidae
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Peroniceras tridorsatum
(Schlüter 1867)
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ammonite |
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Forresteria brancoi
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ammonite |
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Forresteria alluaudi
(Boule et al. 1907)
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ammonite |
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| recombined as Forresteria (Forresteria) alluaudi | ||||||||||
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Cephalopoda
- Ammonoidea
- Baculitidae
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Baculites yokoyamai
(Tokunga and Shimizu 1926)
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ammonite |
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Cephalopoda
- Ammonoidea
- Diplomoceratidae
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? Neocrioceras sp.
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ammonite |
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Cephalopoda
- Ammonoidea
- Scaphitidae
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Scaphites frontierensis
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ammonite |
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Scaphites sagensis
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ammonite |
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Scaphites uintensis
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ammonite |
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Scaphites preventricosus
Cobban 1951
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ammonite |
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Bivalvia
- Pterioida
- Inoceramidae
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Mytiloides herbichi
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clam |
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| Restricted to the "grey member" | ||||||||||
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Mytiloides incertus
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clam |
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| Restricted to the "grey member" | ||||||||||
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Mytiloides scupini
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clam |
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| Restricted to the "grey member" | ||||||||||
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Cremnoceramus waltersdorfensis
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clam |
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| Subspecies: waltersdorfensis. Occurs higher in the section. | ||||||||||
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Cremnoceramus deformis
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clam |
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| Subspecies: deformis and erectus. Occurs higher in the section. | ||||||||||
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Cremnoceramus crassus
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clam |
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| Subspecies: inconstans. Occurs higher in the section. | ||||||||||
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Bivalvia
- Pectinoida
- Posidoniidae
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Didymotis costatus
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clam |
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| Restricted to the "grey member" | ||||||||||
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Chondrichthyes
- Elasmobranchii
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Elasmobranchii indet.
(Bonaparte 1838)
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elasmobranch |
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Chondrichthyes
- Elasmobranchii
- Ptychodontidae
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Ptychodus cf. mortoni
Morton 1842
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elasmobranch |
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Chondrichthyes
- Odontaspidida
- Scapanorhynchidae
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cf. Scapanorhynchus sp.
Woodward 1889
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elasmobranch |
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Gnathostomata
- Pycnodontiformes
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Pycnodontiformes indet.
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bony fish |
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Teleostei
- Ichthyodectiformes
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Ichthyodectiformes indet.
Bardack and Sprinkle 1969
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ray-finned fish |
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Teleostei
- Salmoniformes
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? Enchodontoidei indet.
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ray-finned fish |
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unclassified
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? Prionolepididae indet.
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Teleostei
- Acanthomorpha
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Acanthomorpha indet.
(Rosen 1973)
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ray-finned fish |
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Gnathostomata
- Tselfatiiformes
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Tselfatiiformes indet.
Nelson 1994
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ray-finned fish |
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unclassified
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? Cimolichthyioidei indet.
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Reptilia
- Pterosauria
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Nyctosauridae indet.
(Williston 1903)
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1 individual | |||||||||
| New genus and species | ||||||||||
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= Muzquizopteryx coahuilensis n. gen., n. sp.
Frey et al. 2006
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Frey et al. 2006 | pterosaur |
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| UNAM IGM 8621, near complete skeleton with soft tissues | ||||||||||
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Reptilia
- Archosauria
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Crocodylia indet.
(Owen 1842)
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1 element | crocodile |
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| PAS 629, vertebra | ||||||||||
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Reptilia
- Squamata
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? Varanoidea indet.
Gray 1827
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1 element | lizard |
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| PAS 337, centrum | ||||||||||
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Reptilia
- Squamata
- Mosasauridae
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Mosasauridae indet.
Gervais 1853
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1 specimen | mosasaur |
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| PAS 336, partial tail | ||||||||||
| see common names | ||||||||||
Geography
| Country: | Mexico | State/province: | Coahuila |
| Coordinates: | 28.9° North, 102.4° West (view map) | ||
| Paleocoordinates: | 31.0° North, 71.2° West | ||
| Basis of coordinate: | stated in text | ||
| Altitude: | 1350 meters | ||
| Geographic resolution: | outcrop |
Time
| Period: | Cretaceous | Epoch: | Late/Upper Cretaceous |
| 10 m.y. bin: | Cretaceous 6 | ||
| Key time interval: | Late/Upper Turonian - Early/Lower Coniacian | ||
| Age range of interval: | 93.5 - 85.8 m.y. ago |
Stratigraphy
| Geological group: | Austin | ||||
| Stratigraphic resolution: | formation | ||||
| Stratigraphy comments: Limestone in the quarry has been divided into three members (basal gray, middle yellow, upper white) | |||||
Lithology and environment
| Primary lithology: | concretionary,pyritic lime mudstone |
| Secondary lithology: | marl |
| Lithology description: "The sediments are best described by the German word Plattenkalk. The lithology corresponds to micritic, evenly layered, platy limestone, mostly with internal millimetric bedding (flinze), and intercalated calcareous, fine-layered marls (Fäulen)"..."The sediment sequence is monotoneous and consists of evenly layered platy limestone and interlayered millmetrically-layered marls. The limestone layers are micritic mudstones, wackestones, and packstones, with shell hash. Dismicrite or microsparite only occur occasionally as the result of diagenetic overprint. This limestine is between a few tens of mm and more than 0.5 m thick, massive or millimetrically laminated, and resistant to weathering. Carbonate content of the limestone is always higher than 95%. The interlayered marl units reach thickness of 1 m or more." | |
| Environment: | offshore shelf |
| Geology comments: "Quiet water marine environment. Stagnation and a hostile oxygen-deficient bottom environment are indicated by the near-absence of trace fossil and benthic invertebrate associations...Anoxoic conditions are also indicated by thin laminae to thick horizons with concretions of goethite, which formed from the oxidation of primary pyrite, and by the early diagenetic phosphatization of vertebrate and invertebrate fossils...Low energy currents occurred only occasionally and probablyvery locally...Deposition occurred below storm wave base...The abundance of ammonoids, inoceramids and planktonic foraminifera indicate a water depth of at least 50 m, an open marine shelf environment, and normal stenohaline confitions. The extremely rare shallow water, terrestrial and semi-aquatic organisms, and drift wood suggest a distant coast line (>100 km)." | |
Taphonomy
| Modes of preservation: | body,mold/impression,trace,soft parts,recrystallized,original calcite,replaced with calcite,replaced with pyrite,replaced with phosphate |
| Lagerstätten type: | conservation |
| Size of fossils: | macrofossils,mesofossils,microfossils |
| Spatial orientation: | random |
| Preservation of anatomical detail: | excellent |
| Abundance in sediment: | abundant |
| Articulated whole bodies: | many |
| Associated major elements: | many |
| Disassociated major elements: | many |
| Disassociated minor elements: | many |
| Fragmentation: | occasional |
| Temporal resolution: | snapshot |
| Spatial resolution: | parautochthonous |
| Taphonomy comments: Vertebrates: "The vertebrate assemblage consists of complete and disarticulated specimens, as well as primary fragments of vertebral columns, single isolated bones, scales, etc. They seem to be randomly distributed in the sediment. Skeletons are embedded laterally, sometimes in dorsoventral position. Many skeletons of our collection are fully articulated, and disarticulated skeletal elements of fishes and other vertebrates appear to be a result of decay during post-mortem floating. At present there is no evidence for major current transport on the sea floor. Most vertebrate fossils are compressed, as a consequence of the compaction of the sediment. Some specimens are preserved in 3D, although flattened. In several of these specimens, geopetal collapse is observed. In general, compressed specimens are embedded parallel to the lamination. Delicate morphological elements (e.g., fin rays, gill rakers and filaments) of some specimens are obliquely embedded, indicating that the sediment must have been soft. According to microprobe analysis, bones are frequently preserved as fluorapatite. Phosphatization of soft parts such as intestinal contents, myotomes, gill filaments, cycloid scales and fins of fishes, is observed occasionally and indicates that replacement of organic tissues by fluorapatite occurred at a very early stage of diagenetic mineralization, preceding or accompanying microbial decay, and often prior to sediment compaction. This process of a very early and almost instantaneous phosphatization has been described as a medusa effect by Martill (1993a)."
Invertebrates: Ammonoids are preserved as compressed internal moulds. Most are embedded laterally in the sediment, but occasional diagonally or vertically embedded specimens also occur and suggest the presence of soft or soupy sediment. Aptychi are mostly found isolated; in rare cases, they still rest in the living chamber. Our collection also includes specimens with a phosphatic preservation of the sipho, either complete or with different degrees of fragmentation. Most inoceramids still preserve their thick prismatic shells, although the aragonitic layer is always recrystallized. In a few specimens, the shell is replaced by goethite indicating very early diagenetic replacement of the periostracum by pyrite. Most inoceramid shells are closed, although separated valves, fragmented shells, or rarely shell hash also occur. Calcitic shells such as oysters, ammonoid aptychi, or foraminiferal tests, are preserved with minor recrystallization. Phosphatization of the invertebrate fossils has been recognized in rare occasions, for instance in decapod crustacean carapaces or ammonite siphos." | |
Collection methods and comments
| Reason for describing collection: | general faunal/floral analysis |
Metadata
| Database number: | 92293 | ||
| Authorizer: | R. Butler | Enterer: | R. Butler |
| Modifier: | R. Butler | Research group: | marine invertebrate,taphonomy,vertebrate |
| Created: | 2009-11-05 05:12:10 | Last modified: | 2009-11-05 07:15:14 |
| Access level: | the public | Released: | 2009-11-05 05:12:10 |
Reference information
Primary reference:
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Secondary references:
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