RV-8200, Seymour Island: Bartonian, Antarctica
collected by IAA, DPV/MLP 1982-1990

List of taxa
Where & when
Taphonomy & methods
Metadata & references
Taxonomic list
Invertebrata indet.
Phyllophaga indet. (Flower 1883)
Bargo and Reguero 1998 1 specimen
? Tardigrada or ? Vermilingua indet.
    = ? Pilosa indet.
MacPhee and Reguero 2010
"A second possible xenarthran from the La Meseta Fm of Seymour, a distal phalanx [MLP 88-I-1-95; DPV 6/84] possibly of vermilinguan or tardigradan affin- ity [Marenssi et al., 1994; Bargo and Reguero, 1998], cannot now be located in the MLP collections and therefore cannot be evaluated in this paper."
Decapoda - Raninidae
Lyreidus antarcticus Feldmann and Zinsmeister 1984
Marenssi et al. 1994
Cirripedia indet. (Rafinesque 1816)
Cione and Reguero 1994
Brachiopoda indet. Cuvier 1805
Marenssi et al. 1994
Bivalvia indet. Linnaeus 1758
Cione and Reguero 1994
Pelecypoda indet. Goldfuss 1820
Marenssi et al. 1994
synonym of Bivalvia
Gastropoda indet. Cuvier 1797
Marenssi et al. 1994
Cephalopoda - Nautilida - Aturiidae
Aturia sp. Bronn 1838
Zinsmeister 1987
Cephalopoda - Nautilida - Nautilidae
Eutrephoceras argentinae Del Valle and Fourcade 1976
Zinsmeister 1987
recombined as Euciphoceras argentinae
Elasmobranchii indet. Bonaparte 1838
"teeth of sharks"
Chondrichthyes - Squaliformes - Squalidae
Dalatias licha (Bonnaterre 1788)
Long 1992
Squalus weltoni Long 1992
Long 1992
Squalus woodburnei Long 1992
Long 1992
Chondrichthyes - Squaliformes - Centrophoridae
Centrophorus sp. Müller and Henle 1837
Long 1992
Chondrichthyes - Squatiniformes - Squatinidae
Squatina sp. Dumeril 1806
Long 1992
Chondrichthyes - Lamniformes - Lamnidae
Isurus praecursor Thurmond and Jones 1981
Cione and Reguero 1994 2 specimens
Carcharocles auriculatus (Blainville 1818)
Long 1992
recombined as Carcharodon auriculatus
Lamna cf. nasus
Long 1992
Chondrichthyes - Lamniformes - Odontaspididae
Odontaspis winkleri Leriche 1905
Long 1992
Odontaspis rutoti (Winkler 1878)
Long 1992
recombined as Palaeohypotodus rutoti
Chondrichthyes - Carchariniformes - Carcharhinidae
Scoliodon sp. Muller and Henle 1837
Long 1992
Chondrichthyes - Orectolobiformes - Orectolobidae
Stegostoma cf. varium
Long 1992
Chondrichthyes - Squalomorphii - Pristiophoridae
Pristiophorus lanceolatus (Davis 1888)
Long 1992
recombined as Pristiophorus lanceolata
Chondrichthyes - Squalomorphii - Hexanchidae
Hexanchidae indet. Gray 1851
Long 1992
Teleostei indet. Müller 1846
vertebrae and teeth of fish
Actinopteri - Labriformes - Labridae
Labridae indet. (Cuvier 1816)
Long 1992
Reptilia indet. Laurenti 1768
Reptilia - Testudines - Dermochelyidae
cf. Psephophorus sp. von Meyer 1847
de la Fuente et al. 1995
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]
Reptilia - Testudines
Chelonia indet. (Latreille 1800)
synonym of Testudines
Reptilia - Avetheropoda
Aves indet. Linnaeus 1758
Reptilia - Avetheropoda - Presbyornithidae
? Presbyornithidae indet. Wetmore 1926
Bargo and Reguero 1998 1 specimen
Reptilia - Avetheropoda - Diomedeidae
Diomedeidae indet. Gray 1840
Bargo and Reguero 1998 1 specimen
Reptilia - Avetheropoda - Procellariidae
Procellariidae indet. Vigors 1825
Bargo and Reguero 1998 2 specimens
Reptilia - Avetheropoda - Phoenicopteridae
cf. Phoenicopteridae indet. Bonaparte 1838
Bargo and Reguero 1998 1 specimen
Reptilia - Avetheropoda
Sphenisciformes indet. Sharpe 1891
Delphinornis sp. Wiman 1905
Bargo and Reguero 1998 1 specimen
Reptilia - Avetheropoda - Spheniscidae
Palaeeudyptes gunnari (Wiman 1905)
Myrcha et al. 2002 1 specimen
Reptilia - Avetheropoda
? Mesetaornis sp. Myrcha et al. 2002
Myrcha et al. 2002 1 specimen
Reptilia - Crocodylia
Crocodylia indet. (Owen 1842)
Laurent et al. 2002 1 specimen
Mammalia indet. (Linnaeus 1758)
Bargo and Reguero 1998 1 specimen
Eutheria indet. (Huxley 1880)
"probably marine placental mammal"
Mammalia - Megalonychidae
Megalonychidae indet. Gervais 1855
Vizcaíano and Scillato-Yané 2004
Metatheria indet. (Huxley 1880)
Mammalia - Polydolopidae
Antarctodolops sp. Woodburne and Zinsmeister 1984
Cione and Reguero 1994 1 specimen
UCR 20913, an isolated left M2. Could be _A. dailyi_, _A. mesetaense_, or a third species.
Eurydolops seymouriensis
Cione and Reguero 1994
synonym of Antarctodolops
Antarctodolops mesetaense Chornogubsky et al. 2009
Chornogubsky et al. 2009 1 specimen
MLP 88-I-1-3, a right dentary with m2
Polydolopidae indet. Ameghino 1897
3 specimens
    = Antarctodolops dailyi n. gen., n. sp.
Woodburne and Zinsmeister 1984
right mandible fragment with p3-m1, maxillary fragment with partial alveolus, maxillary fragment with complete LM2
Antarctodolops dailyi
Chornogubsky et al. 2009 7 specimens
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
Eurydolops seymourensis n. gen., n. sp.
Case et al. 1988 1 specimen
synonym of Antarctodolops dailyi
isolated left P3
Microbiotheriidae indet. (Ameghino 1887)
Goin and Carlini 1995
MLP 88-I-1-1
    = Marambiotherium glacialis Goin et al. 1999
Goin et al. 1999
MLP 88-1-1-1, an edentulous left mandibular ramus with the alveoli for p3-m4
Mammalia - Microbiotheria - Microbiotheriidae
? Microbiotheriidae indet. (Ameghino 1887)
Bargo and Reguero 1998 1 specimen
Asteroidea indet. de Blainville 1830
Marenssi et al. 1994
Plantae indet. Haeckel 1866
Marenssi et al. 1994
Magnoliopsida - Fagales - Nothofagaceae
Nothofagus sp. Blume 1850
Cione and Reguero 1994 18 specimens
leaf impressions and carbon films
see common names

Coordinates: 64.2° South, 56.6° West (view map)
Paleocoordinates:64.0° South, 59.7° West
Basis of coordinate:stated in text
Geographic resolution:outcrop
Period:Paleogene Epoch:Eocene
Stage:Bartonian 10 m.y. bin:Cenozoic 3
*Period:Tertiary *Epoch:Eocene - Oligocene
*Local age/stage:Casamayoran - Divisaderan
Key time interval:Bartonian
Age range of interval:41.30000 - 38.00000 m.y. ago
* legacy (obsolete) database fields
Formation:La Meseta Member:Telm 5
Local order:bottom to top
Stratigraphic resolution:group of beds
Stratigraphy comments: 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.
Lithology and environment
Primary lithology:current ripples,wavy/flaser/lenticular bedding,deformed bedding,burrows silty sandstone
Secondary lithology:concretionary,shelly/skeletal poorly lithified sandstone
Includes fossils?Y
Lithology description: 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.
Environment:paralic indet.
Geology comments: 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).
Modes of preservation:body
Size of fossils:macrofossils,mesofossils
Disassociated minor elements:some
Temporal resolution:time-averaged
Spatial resolution:allochthonous
Collection methods and comments
Collection excludes:some macrofossils
Collection methods:sieve,field collection
Reason for describing collection:taxonomic analysis
Collectors:IAA, DPV/MLP Collection dates:1982-1990s
Collection method comments: Repository: University of California, Riverside
Also known as:DVP 6/84, RV 8200
Database number:31173
Authorizer:J. Alroy, E. Vlachos, M. Uhen, M. Clapham Enterer:E. Leckey, E. Vlachos, M. Uhen, M. Clapham
Modifier:M. Clapham Research group:marine invertebrate,vertebrate
Created:2003-04-15 17:08:53 Last modified:2019-08-17 23:52:54
Access level:the public Released:2003-04-15 17:08:53
Creative Commons license:CC BY
Reference information

Primary reference:

8393. M. O. Woodburne and W. J. Zinmeister. 1982. Fossil Land Mammal from Antarctica. Science 218:284-286 [J. Alroy/E. Leckey/E. Leckey]

Secondary references:

43660 C. Acosta Hospitaleche and N. Haidr. 2011. Penguin cranial remains from the Eocene La Meseta Formation, Isla Marambio (Seymour Island), Antarctic Peninsula. Antarctic Science 23(4):369-378 [M. Uhen/M. Uhen]
34464 M. S. Bargo and M. A. Reguero. 1998. Annotated catalogue of the fossil vertebrates from Antarctica housed in the Museo de la Plata, Argentina. I. Birds and Land Mammals from La Meseta Formation (Eocene - Early Oligocene). Associacion Paleontologica Argentina, Publicacion Especial 5:211-221 [M. Uhen/M. Uhen]
57889 J. A. Case. 1988. Paleogene floras from Seymour Island, Antarctic Peninsula. Geology and Paleontology of Seymour Island Antarctic Peninsula 523-540 [J. Zijlstra/J. Zijlstra]
84875% 21560J. C. Case, M. O. Woodburne, and D. S. Chaney. 1988. A new genus of polydolopid marsupial from Antarctica. Geological Society of America Memoir 169:505-521 [J. Alroy/E. Leckey/E. Leckey]
57792 L. Chornogubsky, F. J. Goin, and M. Reguero. 2009. A reassessment of Antarctic polydolopid marsupials (Middle Eocene, La Meseta Formation). Antarctic Science 21(3):285-297 [J. Zijlstra/J. Zijlstra]
47944 A. L. Cione and M. A. Reguero. 1994. New records of the sharks Isurus and Hexanchus from the Eocene of Seymour Island, Antarctica. Proceedings of the Geologists' Association 105:1-14 [M. Uhen/M. Uhen]
66662 M. S. de la Fuente, S. N. Santillana, and S. A. Marensi. 1995. An Eocene leatherback turtle (Cryptodira; Dermochelyidae) from Seymour Island, Antarctica. Studia Geologica Salmanticensia 31:21-34 [E. Vlachos/E. Vlachos]
57928 D. H. Elliot, C. Rinaldi, W. J. Zinsmeister, T. A. Trautman, W. A. Bryant and R. Valle. 1975. Geological investigations on Seymour Island, Antarctic Peninsula. Antarctic Journal 10(4):182-186 [M. Uhen/M. Uhen]
46065 F. J. Goin and A. A. Carlini. 1995. An Early Tertiary Microbiotheriid marsupial from Antarctica. Journal of Vertebrate Paleontology 15(1):205-207 [C. Jaramillo/C. Suarez-Gomez]
57522 F. J. Goin, J. A. Case, M. O. Woodburne, S. F. Vizcaino, and M. A. Reguero. 1999. New Discoveries of "Opposum-like" Marsupials from Antarctica (Seymour Island, Medial Eocene). Journal of Mammalian Evolution 6(4):335-365 [R. Butler/R. Butler]
38065 Y. Laurent, H. Tong, and J. Claude. 2002. New side-necked turtle (Pleurodira: Bothremydidae) from the Upper Maastrichtian of the Petites-Pyrenees (Haute-Garonne, France). Cretaceous Research 23:465-471 [P. Mannion/P. Mannion]
62653 D. J. Long. 1992. An Eocene wrasse (Perciformes; Labridae) from Seymour Island. Antarctic Science 4(2):235-237 [M. Uhen/M. Uhen]
49265 D. J. Long. 1992. Sharks from the La Meseta Formation (Eocene), Seymour Island, Antarctic Peninsula. Journal of Vertebrate Paleontology 12(1):11-32 [M. Uhen/J. Villari/M. Uhen]
57834 R. D. E. MacPhee and M. Reguero. 2010. Reinterpretation of a Middle Eocene record of Tardigrada (Pilosa, Xenarthra, Mammalia) from La Meseta Formation, Seymour Island, West Antarctica. American Museum Novitates 3689:1-21 [J. Zijlstra/J. Zijlstra]
14457 S. A. Marenssi, M. A. Regeuro, S. N. Santillana and S. F. Vizcaino. 1994. Eocene land mammals from Seymour Island, Antarctica: palaeobiogeographical implications. 6(1):3-15 [M. Uhen/M. Uhen/M. Uhen]
196755% 56120A. Myrcha, P. Jadwiszczak, C. P. Tambussi, J. I. Noriega, A. Gazdzicki, A. Tatur, and R. A. Valle. 2002. Taxonomic revision of Eocene Antarctic penguins based on tarsometatarsal morphology. Polish Polar Research 23(1):5-46 [M. Uhen/M. Uhen/M. Uhen]
61035 S. F. Vizcaíano and G. J. Scillato-Yané. 2004. An Eocene tardigrade (Mammalia, Xenarthra) from Seymour Island, West Antarctica. 7(4):407-408 [M. Uhen/K. Williams]
8484 M. O. Woodburne and W. J. Zinsmeister. 1984. The first land mammal from Antarctica and its biogeographic implications. Journal of Paleontology 58(4):913-948 [J. Alroy/E. Leckey/M. Uhen]
59804 W. J. Zinsmeister. 1987. Unusual nautilid occurrence in the upper Eocene La Meseta Formation, Seymour Island, Antarctica. Journal of Paleontology 61:724-726 [M. Clapham/M. Clapham]