RV-8200, Seymour Island (Eocene to of Antarctica)

Also known as DVP 6/84, RV 8200

Where: Antarctica (64.2° S, 56.6° W: paleocoordinates 64.2° S, 59.1° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Telm 5 Member (La Meseta Formation), Bartonian to Bartonian (41.3 - 33.9 Ma)

• From Telm5 or the Cucullaea I allomember. The age model for the La Meseta Formation (and recently-defined Submeseta Formation) is controversial. Strontium isotopes (Ivany et al., 2008) suggest earlier ages, with the La Meseta (Telm1-Telm5) almost entirely Ypresian and the Submeseta (Telm6-Telm7) Middle-Late Eocene. Montes et al. (2013) also created an age model incorporating magnetostratigraphy to support the largely-Ypresian age for the La Meseta and Middle-Late Eocene for the Submeseta. Some mammals are similar to the radiometrically-constrained late early Eocene Paso del Sapo assemblage of Patagonia (Gelfo et al., 2009, Tejedor et al., 2009), but the mammals are not exactly similar (Bond et al., 2011). However, Douglas et al. (2014) re-evaluated the strontium data and used dinoflagellate biostratigraphy to argue for a Lutetian (Telm2-4) and younger (Bartonian to mid-Priabonian for Telm5-6) age range. Amenábar et al. (2019) also found younger ages from dinoflagellates: Lutetian (Telm1-mid Telm 3), Bartonian (mid Telm 3-mid Telm 5), and Priabonian (upper Telm 5), SPDZ10-SPDZ13. This age range is more consistent with the presence of basilosaurid whales in Telm4 and Telm7, as basilosaurids are globally-distributed first in the middle Eocene (Buono et al., 2016). Although the ages are still debated, the dinoflagellate age model of Amenábar et al. (2019) is used here.

• group of beds-level stratigraphic resolution

Environment/lithology: paralic; burrowed, silty sandstone and poorly lithified, concretionary, shelly/skeletal sandstone

• The environment of deposition of this complex unit has been subject to different interpretations, all agreeing in general that Telm5 represents a shallow-marine setting. A study by Wiedman and Feldmann (1988) on the ichnofossil fauna and depositional environment of the La Meseta Formation concluded that the Telm5 setting was a littoral to very shallow sublittoral clastic marine terrain, definitely above storm base and most probably above normal wave base. They agreed with Elliot and Trautrnan (1982) that Units II and III probably represent a tidally dominated environment, but evidence from sedimentary structures is also consistent with a barrier bar model and does not represent a shallowing upward sequence. Elliot and Trautman (1982) favored a deltaic model. The analysis of trace fossils and body fossils (including vertebrate remains and large, abundant wood fragments) indicates variable nearshore, shallow-marine environments. A scenario for the depositional environment could include a combination ebb-tidal (or possibly flood-tidal) delta-barrier island complex (Stilwell & Zinsmeister, 1992).
• Finely laminated beds of silty sandstone, some of which are interbedded with pebbly conglomeratic units interpreted to represent shell banks. The finer-grained beds between the shell banks are finely laminated, and exhibit ripple marks and flaser bedding. Vertical and oblique burrows are common throughout the finer-grained units. Small to large cut-and-fill channel features occur within the sandy siltstone facies. Prominent slump structures and lenses of gravel are associated with these channels. The shell banks consist of individual beds that range in thickness from .5 to 2m, and extend laterally as much as 1km. The banks are characterized by coarse- to fine-grained, well-sorted arkosic sandstone beds that contain pebble- to cobble-sized clasts. Most of the shell banks are extremely fossiliferous.

Size classes: macrofossils, mesofossils

Collected by IAA, DPV/MLP in the 1982-1990s

Collection methods: sieve,

• Repository: University of California, Riverside

Primary reference: M. O. Woodburne and W. J. Zinmeister. 1982. Fossil Land Mammal from Antarctica. Science 218:284-286 [J. Alroy/E. Leckey/E. Leckey]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 31173: authorized by John Alroy, entered by Erin Leckey on 15.04.2003, edited by Matthew Clapham, Mark Uhen and Evangelos Vlachos

Creative Commons license: CC BY (attribution)

Taxonomic list

unclassified
  -
Chondrichthyes
 Elasmobranchii -
Elasmobranchii indet. Bonaparte 1838 elasmobranch
"teeth of sharks"
 Hexanchiformes - Hexanchidae
Hexanchidae indet.8 Gray 1851 cow shark
 Pristiophoriformes - Pristiophoridae
Pristiophorus lanceolatus8 Davis 1888 saw shark
 Squaliformes - Centrophoridae
Centrophorus sp.8 Müller and Henle 1837 gulper shark
 Squaliformes - Squalidae
Squalus woodburnei8 Long 1992 dogfish shark
Squalus weltoni8 Long 1992 dogfish shark
 Squaliformes - Dalatiidae
Dalatias licha8 Bonnaterre 1788 shark
 Squatiniformes - Squatinidae
Squatina sp.8 Dumeril 1806 angel shark
 Carcharhiniformes - Carcharhinidae
Scoliodon sp.8 Muller and Henle 1837 requiem shark
 Orectolobiformes - Stegostomatidae
Stegostoma cf. varium8 carpet shark
 Lamniformes - Odontaspididae
Odontaspis winkleri8 Leriche 1905 sand tiger shark
"Odontaspis rutoti" = Palaeohypotodus rutoti8 Winkler 1878 sand tiger shark
 Lamniformes - Lamnidae
"Carcharocles auriculatus" = Carcharodon auriculatus8, Isurus praecursor4, Lamna cf. nasus8
"Carcharocles auriculatus" = Carcharodon auriculatus8 Blainville 1818 white shark
Isurus praecursor4 Thurmond and Jones 1981 mackerel shark
Lamna cf. nasus8 mackerel shark
Reptilia
  -
Reptilia indet. Laurenti 1768 reptile
 Testudines - Dermochelyidae
cf. Psephophorus sp.5 von Meyer 1847 leatherback
MLP 92-II-2-113, a fragment of an epithecal plate (DPV 2/84, TELM 4), MLP 94-III-15-28 a fragment of epithecal corace with four plates [Coquine of Miles (DPV 2/84), TELM 3/4]
 Testudines -
"Chelonia indet." = Testudines
"Chelonia indet." = Testudines Batsch 1788 turtle
Aves
  -
Aves indet. Linnaeus 1758 bird
 Procellariiformes - Diomedeidae
Diomedeidae indet.1 Gray 1840 albatross
 Procellariiformes - Procellariidae
Procellariidae indet.1 Vigors 1825 petrel
 Neornithes -
Sphenisciformes indet. penguin
penguins
 Sphenisciformes -
? Mesetaornis sp.11 Myrcha et al. 2002 penguin
Delphinornis sp.1 Wiman 1905 penguin
 Sphenisciformes - Spheniscidae
Palaeeudyptes gunnari11 Wiman 1905 penguin
 Anseriformes - Presbyornithidae
? Presbyornithidae indet.1 Wetmore 1926 waterfowl
 Phoenicopteriformes - Phoenicopteridae
cf. Phoenicopteridae indet.1 Bonaparte 1838 flamingo
Reptilia
 Loricata -
Crocodylia indet.7 crocodilian
Mammalia
 Mammalia -
 Tribosphenida -
Metatheria indet. Huxley 1880 metatherian
 Polydolopimorphia - Polydolopidae
"Antarctodolops sp." = Antarctodolops4, "Eurydolops seymouriensis" = Antarctodolops4, Antarctodolops mesetaense3, "Antarctodolops dailyi" = Antarctodolops dailyi3, "Antarctodolops dailyi n. gen. n. sp." = Antarctodolops dailyi13, "Eurydolops seymourensis n. gen. n. sp." = Antarctodolops dailyi2
"Antarctodolops sp." = Antarctodolops4 Woodburne and Zinsmeister 1984 metatherian
UCR 20913, an isolated left M2. Could be _A. dailyi_, _A. mesetaense_, or a third species.
"Eurydolops seymouriensis" = Antarctodolops4 metatherian
Antarctodolops mesetaense3 Chornogubsky et al. 2009 metatherian
MLP 88-I-1-3, a right dentary with m2
"Antarctodolops dailyi" = Antarctodolops dailyi3 metatherian
MLP 87-II-1-1, MLP 88-I-1-4, MLP 88-I-1-2, UCR 22355 (holotype of _Eurydolops seymourensis_), UCR 20910 (holotype of _Antarctodolops dailyi_), UCR 20911, UCR 20912
"Antarctodolops dailyi n. gen. n. sp." = Antarctodolops dailyi13 metatherian
"Eurydolops seymourensis n. gen. n. sp." = Antarctodolops dailyi2 metatherian
isolated left P3
 Microbiotheria - Microbiotheriidae
? Microbiotheriidae indet.1 Ameghino 1887 marsupial
 Tribosphenida -
Marambiotherium glacialis6 Goin et al. 1999 marsupial
MLP 88-I-1-1
Eutheria indet. eutherian
"probably marine placental mammal"
 Megatherioidea - Megalonychidae
Megalonychidae indet.12 Gervais 1855 edentate
Actinopteri
 Teleostei -
Teleostei indet.
vertebrae and teeth of fish
 Labriformes - Labridae
Labridae indet.9 Cuvier 1816
Asteroidea
  -
Asteroidea indet.10 de Blainville 1830 sea star
Thecostraca
 Cirripedia -
Cirripedia indet.4 Rafinesque 1816 barnacle
Malacostraca
 Decapoda - Lyreididae
Lyreidus antarcticus10 Feldmann and Zinsmeister 1984 crab
Gastropoda
  -
Gastropoda indet.10 Cuvier 1795 snail
Bivalvia
  -
"Bivalvia indet." = Bivalvia4, "Pelecypoda indet." = Bivalvia10
"Bivalvia indet." = Bivalvia4 Linnaeus 1758 clam
"Pelecypoda indet." = Bivalvia10 Linnaeus 1758 clam
Cephalopoda
 Nautilida - Nautilidae
"Eutrephoceras argentinae" = Euciphoceras argentinae14
"Eutrephoceras argentinae" = Euciphoceras argentinae14 Del Valle and Fourcade 1976 nautiloid
 Nautilida - Aturiidae
Aturia sp.14 Bronn 1838 nautiloid
Brachiopoda
  -
Brachiopoda indet.10 Cuvier 1805
unclassified
  -
Plantae indet.10 Haeckel 1866
Angiospermae
 Fagales - Nothofagaceae
Nothofagus sp.4 Blume 1850
leaf impressions and carbon films