Snow Hill Island Formation
Stratigraphic range: Early Maastrichtian
71.2–70.8 Ma
↓
Artist's reconstruction of the paleoenvironment of the Snow Hill Island Formation.
TypeGeological formation
Unit ofMarambio Group
Sub-unitsGamma & Herbert Sound Members
UnderliesLopez de Bertodano Formation
OverliesSanta Marta Formation
Lithology
PrimarySandstone
OtherMudstone
Location
Coordinates63°54′S 57°54′W / 63.9°S 57.9°W / -63.9; -57.9
Approximate paleocoordinates61°48′S 68°30′W / 61.8°S 68.5°W / -61.8; -68.5
RegionJames Ross Island, James Ross Island group
CountryAntarctica

Geologic map of Seymour Island, Antarctica with Snow Hill Island Formation in dark green

The Snow Hill Island Formation is an Early Maastrichtian geologic formation found on James Ross Island, James Ross Island group, Antarctica.[1] Remains of a paravian theropod Imperobator antarcticus[2] have been recovered from it, as well as the elasmarian ornithopods Trinisaura santamartaensis, Biscoveosaurus and Morrosaurus antarcticus, the ankylosaurian Antarctopelta oliveroi, and the shark Notidanodon sp. Alongside these described genera are also the remains of indeterminate elasmosaurids,[3] lithostrotian titanosaurs and an indeterminate pterosaur.[4]

In the Herbert Sound Member of the Snow Hill Island Formation, bivalves, ammonites, and fish were found.[5]

Fossil content

Vertebrate

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Plesiosaurs

Plesiosaurs
Genus Species Presence Material Notes Images
Elasmosauridae Gen. et. sp. indet. "MLP 11-II-20-4, one cervical vertebra preserving a partial rib; MLP 86-X-28-3, two cervical vertebrae; MLP 86-X-28-(2–6), 10 posterior cervical vertebrae articulated with three pectoral vertebrae, part of two dorsal vertebrae, ribs, and indeterminate fragments."[6]
Vegasaurus V. molyi Cape Lamb member, Vega Island. Partial Skeleton (MLP 93-I-5-1). A plesiosaur.

Mosasaurs

Mosasaurs
Genus Species Presence Material Notes Images
Taniwhasaurus[7] T. antarcticus James Ross Island. IAA 2000-JR-FSM-1, containing a skull measuring 72 cm (28 in) long, teeth, some vertebrae, and rib fragments. A tylosaur.
Taniwhasaurus
Taniwhasaurus

Dinosaurs

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
Dinosaurs
Genus Species Presence Material Notes Images
Antarcticavis A. capelambensis[8] Cape Lambe Member, Vega Island. Partial Skeleton (SDSM 78147) consists of two thoracic vertebrae, the sternum keel, the right coracoid and shoulder blade, the sternal part of the left coracoid, the right upper arm, parts of the left upper arm, the proximal right ulna, the proximal left ulna and radius (articulated), the proximal right carpometacarpus, the proximal left carpometacarpus, the distal left carpometacarpus, the synsacrum, the right and left thighs, the proximal right tibiotarsus, the right and left distal tibiotarsus, and the proximal right tarsometatarsus.
Antarctopelta A. oliveroi Santa Marta Cove. A partial skeleton (MLP 86-X-28-1) consists of three isolated teeth, part of the lower jaw with another tooth in situ, some other skull fragments, vertebrae of the neck, back, hips and tail, some shoulder and hip bones (scapula, ilium) a thigh bone (femur), foot and hand bones (five metapodials and two phalanges), and numerous pieces of armor. A Parankylosaur
Antarctopelta_Size_Comparison
Antarctopelta_Size_Comparison
Biscoveosaurus Indeterminate Cape Lamb Member.[9][10] Dentaries, teeth, a braincase, parts of the maxillae, forelimb elements, assorted vertebrae, and the pectoral girdle. An ornithopod.
Iguanodontidae Indeterminate Cape Lamb Member.
Imperobator I. antarcticus Cape Lamb Member, Naze Peninsula.[11] A single specimen that contains skull fragments possibly from the premaxilla, maxilla, and dentary as well as a caudal vertebra, teeth, and pedal elements, UCMP 276000. A large paravian.
Life restoration
Morrosaurus M. antarcticus Cape Lamb Member.[12] Fragmentary right hind limb.[12] An elasmarian ornithopod.
Titanosauria Indeterminate. Santa Marta Cove. Partial caudal vertebra.
Trinisaura T. santamartaensis Santa Marta Cove, in the lower levels of the formation.[13] MLP08-III-1-1, disarticulated and partial skeleton that includes one incomplete dorsal vertebra, three sacral centra, seven caudal vertebrae; two incomplete dorsal rib shafts, one proximal haemal arch, incomplete right scapulocoracoid, incomplete right humerus, two metacarpals, both ilia, right pubis, right ischium, right femur, right distal tibia, incomplete metatarsal III, first phalanx of pedal digit III, two phalanges of pedal digit IV, and indeterminate fragments. An elasmarian ornithopod.

Fish

Fish
Genus Species Presence Material Notes Images
Chimaera C. zangerli Santa Marta Cove, James Ross Island. A chimaera.
Chlamydoselachus C. thompsoni Santa Marta Cove, James Ross Island. Complete dentition. A frilled shark.
Edaphodon E. snowhillensis Herbert Sound Member.[14] Complete dentition.[14] A large species of chimaera.
Notidanodon N. dentatus Cape Lamb Member, Vega Island. A cow shark.

Pterosaur

Pterosaurs
Genus Species Presence Material Notes Images
Pterodactyloidea gen. et sp. Indet. Camp Lamb, Vega Island. MN 7801-V, a wing metacarpal IV.[15] A pterosaur with an estimated wingspan of 4 to 5 meters.[15]

Invertebrate

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
Invertebrates
Genus Species Presence Material Notes Images
Fungiacyathus F. deltoidophorus Karlsen Cliffs Member.[16]
Scleractinia indet. Unidentifiable Karlsen Cliffs Member.[16]

See also

References

  1. ^ di Pasquo, M.; Martin, J.E. (2013). "Palynoassemblages Associated with a Theropod Dinosaur from the Snow Hill Island Formation (lower Maastrichtian) at the Naze, James Ross Island, Antarctica". Cretaceous Research. 45: 135–154. doi:10.1016/j.cretres.2013.07.008. hdl:11336/80121.
  2. ^ Ely & Case, 2019
  3. ^ O'Gorman, 2012, p.2
  4. ^ Reguero, Marcelo & Gasparini, Zulma & Olivero, Eduardo & Coria, Rodolfo & Fernandez, Marta & O'Gorman, José & Gouiric Cavalli, Soledad & Acosta Hospitaleche, Carolina & Bona, Paula & Iglesias, Ari & Gelfo, Javier N. & Raffi, María & Moly, Juan. (2022). Late Campanian-Early Maastrichtian Vertebrates From The James Ross Basin, West Antarctica: Updated Synthesis, Biostratigraphy, And Paleobiogeography. Anais da Academia Brasileira de Ciências. 20211142. 10.1590/0001-3765202220211142.
  5. ^ O'Gorman, 2012, p.3
  6. ^ O'Gorman, J.P. 2012. The oldest elasmosaurs (Sauropterygia, Plesiosauria) from Antarctica, Santa Marta Formation (upper Coniacian? Santonian-?upper Campanian) and Snow Hill Island Formation (upper Campanian-?lower Maastrichtian), James Ross Island. Polar Research 31. 1–10. Accessed 2019-04-13. doi:10.3402/polar.v31i0.11090
  7. ^ Fernando E. Novas; Marta S. Fernandez; Zulma B. de Gasparini; Juan M. Lirio; Héctor J. Nuñez; Pablo Puerta (2002). "Lakumasaurus antarcticus, n. gen. et sp., a new mosasaur (Reptilia, Squamata) from the Upper Cretaceous of Antarctica". Ameghiniana. 39 (2): 245–249. hdl:11336/136746. S2CID 128304133.
  8. ^ Amanda Cordes-Person; Carolina Acosta Hospitaleche; Judd Case; James Martin (2020). "An enigmatic bird from the lower Maastrichtian of Vega Island, Antarctica". Cretaceous Research. 108: Article 104314. doi:10.1016/j.cretres.2019.104314.
  9. ^ Lamanna, Matthew C.; Case, Judd A.; Roberts, Eric M.; Arbour, Victoria M.; Ely, Ricardo C.; Salisbury, Steven W.; Clarke, Julia A.; Malinzak, D. Edward; West, Abagael R.; O'connor, Patrick M. (2019). "Late Cretaceous non-avian dinosaurs from the James Ross Basin, Antarctica: description of new material, updated synthesis, biostratigraphy, and paleobiogeography". Advances in Polar Science. 30 (3): 228–250. doi:10.13679/j.advps.2019.0007.
  10. ^ Stilwell, Jeffrey D.; Long, John A. (2011-10-12). Frozen in Time: Prehistoric Life in Antarctica. Csiro Publishing. ISBN 978-0-643-10402-0.
  11. ^ Ely, Ricardo C.; Case, Judd A. (2019-09-01). "Phylogeny of a new gigantic paravian (Theropoda; Coelurosauria; Maniraptora) from the Upper Cretaceous of James Ross Island, Antarctica". Cretaceous Research. 101: 1–16. doi:10.1016/j.cretres.2019.04.003. ISSN 0195-6671. S2CID 146325060.
  12. ^ a b Rozadilla, Sebastián; Agnolin, Federico L.; Novas, Fernando E.; Aranciaga Rolando, Alexis M.; Motta, Matías J.; Lirio, Juan M.; Isasi, Marcelo P. (2016-01-01). "A new ornithopod (Dinosauria, Ornithischia) from the Upper Cretaceous of Antarctica and its palaeobiogeographical implications". Cretaceous Research. 57: 311–324. doi:10.1016/j.cretres.2015.09.009. ISSN 0195-6671.
  13. ^ Coria, Rodolfo A.; Moly, Juan J.; Reguero, Marcelo; Santillana, Sergio; Marenssi, Sergio (2013-04-01). "A new ornithopod (Dinosauria; Ornithischia) from Antarctica". Cretaceous Research. 41: 186–193. doi:10.1016/j.cretres.2012.12.004. hdl:11336/76749. ISSN 0195-6671.
  14. ^ a b Gouiric-Cavalli, Soledad; Cabrera, Daniel A.; Cione, Alberto L.; O'Gorman, José P.; Coria, Rodolfo A.; Fernández, Marta (2015-09-03). "The first record of the chimaeroid genus Edaphodon (Chondrichthyes, Holocephali) from Antarctica (Snow Hill Island Formation, Late Cretaceous, James Ross Island)". Journal of Vertebrate Paleontology. 35 (5): e981128. doi:10.1080/02724634.2015.981128. hdl:11336/53488. ISSN 0272-4634. S2CID 129091192.
  15. ^ a b KELLNER, ALEXANDER W.A.; RODRIGUES, TAISSA; COSTA, FABIANA R.; WEINSCHÜTZ, LUIZ C.; FIGUEIREDO, RODRIGO G.; SOUZA, GEOVANE A. DE; BRUM, ARTHUR S.; ELEUTÉRIO, LÚCIA H.S.; MUELLER, CARSTEN W.; SAYÃO, JULIANA M. (2019). "Pterodactyloid pterosaur bones from Cretaceous deposits of the Antarctic Peninsula". Anais da Academia Brasileira de Ciências. 91 (suppl 2): e20191300. doi:10.1590/0001-3765201920191300. ISSN 1678-2690. PMID 31800676. S2CID 208642733.
  16. ^ a b Videira-Santos, Roberto; Tobin, Thomas S.; Scheffler, Sandro Marcelo (2022-08-14). "New occurrences of caryophylliid and fungiacyathid scleractinian corals from the Santa Marta and Snow Hill Island formations (Upper Cretaceous, Antarctica)". Cretaceous Research. 140: 105338. doi:10.1016/j.cretres.2022.105338. ISSN 0195-6671. S2CID 251576799.

Bibliography

Further reading

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