Short Note: An ibis-like bird from the Upper La Meseta Formation (Late Eocene) of Seymour Island, Antarctica

2008 ◽  
Vol 20 (4) ◽  
pp. 413-414 ◽  
Author(s):  
Piotr Jadwiszczak ◽  
Andrzej GaŹdzicki ◽  
Andrzej Tatur
Keyword(s):  
Middle Eocene ◽  
Short Note ◽  
Late Eocene ◽  
Taxonomic Position ◽  
Tierra Del Fuego ◽  
Wading Birds ◽  
The Family ◽  
La Meseta Formation ◽  
Fossil Bones ◽  
Seymour Island

Ibises are a group of medium- to large-sized, mainly wading birds in the family Threskiornithidae (Aves: Ciconiiformes; see also discussion in Mayr 2002). They are known from all the continents except Antarctica, though one species breeds as far south as Tierra del Fuego (del Hoyoet al.1992, p. 499). The oldest fossil bones (including skull elements) attributed to ibises are those ofRhynchaeites messelensisWittich, 1898 from the Middle Eocene of Messel, Germany (Peters 1983, Mayr 2002). Another supposed member of this group is the Pondaung bird from the late Middle Eocene of Myanmar (formerly Burma) represented solely by an incomplete tibiotarsus (Stidhamet al.2005, fig. 2). The taxonomic position ofMinggangia changgouensisHou, 1982 from the Late Eocene of China (Hou 1982) was recently questioned by Stidhamet al.(2005, p. 183). Here, we present a partial bill from the Eocene La Meseta Formation (Seymour Island, Antarctica) which most closely resembles that of ibises.

Late Eocene Decapod Crustacea from North Westland, South Island, New Zealand

1990 ◽  
Vol 64 (5) ◽  
pp. 779-797 ◽  
Author(s):  
Rodney M. Feldmann ◽  
Phillip A. Maxwell
Keyword(s):  
New Zealand ◽  
Deep Water ◽  
Middle Eocene ◽  
Late Eocene ◽  
Decapod Crustaceans ◽  
Fecal Pellets ◽  
Decapod Crustacea ◽  
La Meseta Formation ◽  
Seymour Island ◽  
Water Facies

Eight species of brachyuran decapod crustaceans are recorded from coastal outcrops of Island Sandstone between Perpendicular Point and Punakaiki, Westland, New Zealand. The fauna consists of three raninids—Laeviranina pororariensis (Glaessner), L. keyesi n. sp., Lyreidus bennetti n. sp.; two portunids—Rhachiosoma granuliferum (Glaessner), Pororaria eocenica Glaessner; a goneplacid—Carcinoplax temikoensis n. sp.; and two majids—Leptomithrax griffini n. sp., Notomithrax allani n. sp. Together, they form the most diverse brachyuran assemblage yet described from New Zealand. The decapods are preserved in unusual elliptical masses, with their long axes typically parallel to bedding, containing superbly preserved cuticle often surrounded by well-formed fecal pellets, probably of decapod origin. The accumulations are interpreted to be mechanical concentrations within depressions produced by decapods or associated spatangoid echinoids. Although seven of the species have been recorded only from the Island Sandstone, Rhachiosoma granuliferum (Glaessner) is now known to occur in the correlative deep-water facies of the Kaiata Formation in North Westland, as well as in the Tapui Sandstone, North Otago (middle Eocene), and from coeval rocks at Snowdrift Quarry, southeast Otago. The raninids suggest comparison with congeneric forms from Snowdrift Quarry and the Tapui Sandstone, as well as with the La Meseta Formation, Seymour Island, Antarctica. Based upon associated foraminiferans, a Kaiatan–Runangan (late Eocene) age is assigned to this fauna. The occurrences of Carcinoplax, Leptomithrax, and Notomithrax represent paleobiogeographic and stratigraphic records for the genera.

Short Note: An intriguing penguin bone from the Late Eocene of Seymour Island, Antarctic Peninsula

2008 ◽  
Vol 20 (6) ◽  
pp. 589-590 ◽  
Author(s):  
Piotr Jadwiszczak
Keyword(s):  
Antarctic Peninsula ◽  
Short Note ◽  
Late Eocene ◽  
New Genus And Species ◽  
Type Specimens ◽  
West Antarctic ◽  
Antarctic Convergence ◽  
La Meseta Formation ◽  
The Antarctic ◽  
Seymour Island

Penguins (Aves: Sphenisciformes) are interesting to both neontologists and palaeontologists (e.g. Davis & Renner 2003). The fossil record of these extremely specialized inhabitants of the Southern Hemisphere extends back to the Palaeocene epoch (Slack et al. 2006). Extinct penguins are known from localities within the range of their modern-day relatives (Fordyce & Jones 1990), and the oldest diverse assemblage comes from the Eocene La Meseta Formation of Seymour Island, Antarctic Peninsula, the only such locality south of the Antarctic Convergence (Myrcha et al. 2002, Jadwiszczak 2006a). Several collections amounting to over three thousand bones (mainly isolated skeletal elements) have been acquired since 1901 from that formation, and 15 penguin species have been erected so far (Jadwiszczak 2006a, table 1, Tambussi et al. 2006). Only ten of them (grouped into six genera) appear to be taxonomically distinct, and their type specimens are tarsometatarsi (Simpson 1971, Myrcha et al. 2002, Jadwiszczak 2006a, 2006b, p. 296). Individuals from six species belonging to four genera most probably were not larger than those of Aptenodytes forsteri G.R. Gray, 1844, the heaviest and tallest extant penguin (Jadwiszczak 2001, table 3). Interestingly, representatives of all ten species may have co-existed in the West Antarctic during the Late Eocene epoch, just prior to the final break-up of Gondwana (Jadwiszczak 2006a). Presented here is an intriguing partial tarsometatarsus of a small-sized penguin from the Late Eocene of Antarctic Peninsula, probably representing a new genus and species.

The youngest record of fossil land mammals from Antarctica; its significance on the evolution of the terrestrial environment of the Antarctic Peninsula during the late Eocene

1997 ◽  
Vol 71 (2) ◽  
pp. 348-350 ◽  
Author(s):  
S. F. Vizcaino ◽  
M. Bond ◽  
M. A. Reguero ◽  
R. Pascual
Keyword(s):  
Antarctic Peninsula ◽  
Present Note ◽  
Late Eocene ◽  
South American ◽  
Terrestrial Environment ◽  
Shallow Marine ◽  
Early Oligocene ◽  
La Meseta Formation ◽  
The Antarctic ◽  
Seymour Island

The record of fossil land mammals from Antarctica has been restricted previously to the middle levels of the Eocene-?early Oligocene La Meseta Formation in Seymour Island, Antarctic Peninsula. This mostly shallow-marine sequence was divided informally into seven subunits (Tertiary Eocene La Meseta or TELM 1 to 7) by Sadler (1988). Land mammals, representing South American lineages of marsupials, edentates, and ungulates were recovered from TELM 3, 4, and 5 (Marenssi et al., 1994; Vizcaíno et al., 1994). The purpose of the present note is to report the discovery of a well-preserved ungulate tooth from the uppermost level of the La Meseta Formation (TELM 7) and to discuss its paleoenvironmental implications.

An Eocene wrasse (Perciformes; Labridae) from Seymour Island

1992 ◽  
Vol 4 (2) ◽  
pp. 235-237 ◽  
Author(s):  
Douglas J. Long
Keyword(s):  
Climatic Change ◽  
Trophic Structure ◽  
Late Eocene ◽  
Pharyngeal Tooth ◽  
Tooth Plate ◽  
Antarctic Waters ◽  
La Meseta Formation ◽  
First Occurrence ◽  
Wide Scale ◽  
Seymour Island

A nearly complete lower pharyngeal tooth-plate from a large (over 60 cm long) fossil wrasse (Perciformes: Labridae) was recently recovered from the middle to late Eocene La Meseta Formation on Seymour Island, Antarctic Peninsula. This find increases the number of teleosts from the Eocene of Antarctica to five taxa, and further illustrates the diversity of the ichthyofauna in the Eocene Weddellian Sea prior to wide-scale climatic change in the Southern Ocean. The fossil wrasse represents the first occurrence of this family in Antarctica, and is one of the oldest fossils of this family from the Southern Hemisphere. Wrasses are not found in Antarctic waters today, and probably became extinct during the Oligocene due to a combination of climatic change, loss of shallow-water habitat, and changes in the trophic structure of the Wedell Sea.

scholarly journals Middle Palaeogene dinoflagellate cysts from Tierra del Fuego, Argentina: biostratigraphy and palaeoenvironments

2008 ◽  
Vol 27 (1) ◽  
pp. 75-94 ◽  
Author(s):  
G. R. Guerstein ◽  
M. V. Guler ◽  
G. L. Williams ◽  
R. A. Fensome ◽  
J. O. Chiesa
Keyword(s):  
Cold Water ◽  
Middle Eocene ◽  
Late Eocene ◽  
High Ratio ◽  
Tierra Del Fuego ◽  
New Combination ◽  
Lower Member ◽  
Circumpolar Current ◽  
Calcareous Microfossils ◽  
Latest Eocene

Abstract. Palynological data from four surface sections in northern Tierra del Fuego, southern Argentina, provide a biostratigraphical and palaeoenvironmental framework for the lower member of the La Despedida Formation and the Cabo Peña Formation in their type areas. Selected dinoflagellate cyst (dinocyst) events indicate that the age of the lower member of the La Despedida Formation is Middle Eocene and that of the Cabo Peña Formation is Late Eocene–earliest Oligocene. The age assigned to the La Despedida Formation agrees with determinations based on calcareous microfossils, but there is a potential discrepancy regarding the Cabo Peña Formation. According to recent stratigraphic studies, the Cabo Domingo Group, which includes the Cabo Peña Formation, is Late Eocene–Miocene in age. The palynomorph assemblages from the lower member of the La Despedida Formation contain the endemic ‘Transantarctic Flora’, which reflects marginal marine conditions. The maximum abundance of Enneadocysta spp. reflects more open-sea conditions and a warming event during the late Middle Eocene. The lower part of the Cabo Peña Formation has a high ratio of dinocysts to sporomorphs and an abundance of Nematosphaeropsis lemniscata, Reticulatosphaera actinocoronata and Impagidinium spp., suggesting an oceanic to outer neritic environment. Abundant Gelatia inflata and protoperidiniacean cysts indicate cool surface waters rich in dissolved nutrients. These cold-water markers may reflect the development of the Antarctic Circumpolar Current, an important event in the transition from a greenhouse to an icehouse climate mode. Toward the top of the sections, the lower ratios of dinocysts to sporomorphs, as well as the composition of the dinocyst assemblages, reflect a neritic rather than an oceanic setting. This palynological change may be due to eustatic sea-level lowering caused by cooling during the latest Eocene–earliest Oligocene. A new species, Spiniferites scalenus, is described and the new combination Lingulodinium echinatum proposed; an emendation for the latter species is also proposed.

scholarly journals First articulated skeleton of Palaeeudyptes gunnari from the late Eocene of Isla Marambio (Seymour Island), Antarctica

2010 ◽  
Vol 22 (3) ◽  
pp. 289-298 ◽  
Author(s):  
Carolina Acosta Hospitaleche ◽  
Marcelo Reguero
Keyword(s):  
Late Eocene ◽  
La Meseta Formation ◽  
Systematic Determination ◽  
Specific Assignment ◽  
Seymour Island

AbstractThe first articulated skeleton of a penguin from the late Eocene of Antarctica is described. MLP 96-I-6-13 comes from the upper Submeseta Allomember (La Meseta Formation) of Isla Marambio (locality DPV 10/84). The significance of this finding in the context of the Anthropornis nordenskjoeldi biozone is discussed. An osteologic description of the recovered elements and a brief discussion of its systematic determination are provided. MLP 96-I-6-13 is the first articulated skeleton with sure specific assignment to Palaeeudyptes gunnari (Wiman, 1905), a species previously known only through isolated tarsometatarsi and included in the groups of Wiman.

scholarly journals Sakhalinencyrtus leleji Simutnik gen. et sp. nov. of earliest Encyrtidae (Hymenoptera, Chalcidoidea) from Sakhalinian amber

2021 ◽  
Vol 84 ◽  
pp. 361-372
Author(s):  
Serguei A. Simutnik ◽  
Evgeny E. Perkovsky ◽  
Dmitry V. Vasilenko
Keyword(s):  
New Genus ◽  
Middle Eocene ◽  
Late Eocene ◽  
Apical Position ◽  
Male Specimen ◽  
Stem Group ◽  
Filum Spinosum ◽  
The Family

Another earliest representative of the family Encyrtidae, Sakhalinencyrtus leleji Simutnik gen. et sp. nov., is described and illustrated based on a male specimen from the middle Eocene Sakhalinian amber. Similarly to other Encyrtidae from Sakhalinian amber, the new fossil fundamentally differs from encyrtids from late Eocene European ambers as well as from modern ones. Moreover, it probably belongs to a stem group of the family. The new genus is characterized by extremely apical position of cerci, long veins of the forewing with expanded parastigma, stigmal vein with long uncus, and absence of filum spinosum. The forewing venation of the new genus is very similar to that of Sugonjaevia Simutnik, 2015, but these genera differ by the structure of Mt8, hypopygium, genitalia, and clava.

Record of Late Miocene glacial deposits on Isla Marambio (Seymour Island), Antarctic Peninsula

2009 ◽  
Vol 22 (2) ◽  
pp. 193-198 ◽  
Author(s):  
Sergio A. Marenssi ◽  
Silvio Casadío ◽  
Sergio N. Santillana
Keyword(s):  
Antarctic Peninsula ◽  
Late Miocene ◽  
Late Eocene ◽  
Weddell Sea ◽  
Volcanic Group ◽  
Lower Oligocene ◽  
La Meseta Formation ◽  
James Ross Island ◽  
Stratigraphic Sequences ◽  
Seymour Island

AbstractWe report and describe two new small diamictite outcrops on Isla Marambio (Seymour Island), Antarctic Peninsula. These rocks rest on an erosional unconformity on top of the Eocene La Meseta Formation and are unconformably covered by glaciomarine rocks of the ?Pliocene–Pleistocene Weddell Sea Formation. The lithology, fossil content and isotopic ages obtained strongly suggest that the rocks belong to the Hobbs Glacier Formation and support a Late Miocene age for this unit. Additionally, the dated basalt clast provides the oldest age (12.4 Ma) for the James Ross Island Volcanic Group recorded up to now. The here described diamictite cannot be confidently correlated with a glaciomarine unit previously assigned to the Late Eocene–Lower Oligocene taken as proof that initial expansion of ice on Antarctica encompassed the entire continent synchronously in the earliest Oligocene. However, it is now evident that there are likely to be more, short but important, stratigraphic sequences of key regional and Antarctic wide interest preserved on the plateau of Isla Marambio.

A new Eocene crab (Crustacea, Decapoda) from Seymour Island, Antarctica

1995 ◽  
Vol 7 (3) ◽  
pp. 277-281 ◽  
Author(s):  
María B. Aguirre-Urreta ◽  
Sergio Marenssi ◽  
Sergio Santillana
Keyword(s):  
New Zealand ◽  
High Latitude ◽  
Late Eocene ◽  
Early Tertiary ◽  
La Meseta Formation ◽  
Seymour Island

A new xanthid crab, Tumidocarcinus foersteri n. sp. is described from the La Meseta Formation on Seymour Island, Antarctica. The fossils were obtained from the Allomember Submeseta of Late Eocene age. As other representatives of the genus Tumidocarcinus were only known from New Zealand and Australia, this finding provides new insights on the palaeobiogeography of high latitude faunas during the Early Tertiary.

Definitive specimens of Merlucciidae (Gadiformes) from the Eocene James Ross Basin of Isla Marambio (Seymour Island), Antarctic Peninsula

2012 ◽  
Vol 24 (5) ◽  
pp. 467-472 ◽  
Author(s):  
Kerin M. Claeson ◽  
Joseph T. Eastman ◽  
Ross D. E. Macphee
Keyword(s):  
Antarctic Peninsula ◽  
Deep Sea ◽  
Fossil Record ◽  
Middle Eocene ◽  
Mental Foramen ◽  
The Arctic ◽  
Lateral Aspect ◽  
La Meseta Formation ◽  
Freshwater Environments ◽  
Seymour Island

AbstractAn isolated partial right dentary (BAS D.515.2) collected by the British Antarctic Survey prompted a re-evaluation of gadiform remains from the La Meseta Formation (conventionally middle Eocene) of Isla Marambio (Seymour Island), Antarctic Peninsula. Modern gadiforms (hakes and cods) range from the Arctic to Antarctic, inhabiting deep sea benthic, shore, estuarine, and freshwater environments. Based on a fossil record primarily composed of otoliths, they are known to extend back to the Eocene and Oligocene. The new specimen was recovered from the fossil penguin locality D.515. It is characterized by a single row of sharp, ankylosed teeth set upon robust bony pedestals. The surface anterior to the mental foramen exhibits ascending and descending ridges with slightly rugose texture. The ascending ridge is fractured, but partially covers the lateral aspect of the tooth row. BAS D.515.2 is unlike the dentary of macrourid gadiforms, also recovered from the Eocene of Antarctica. BAS D.515.2 preserves several features similar to previously published accounts of the gadiform “†Mesetaichthys” from Isla Marambio. These specimens are probably the same taxon and their combined character suite indicates it is a member of Merluccidae. Thus, these are the only non-otolithic skeletal specimens of an Eocene hake known outside of the London Clay's †Rhinocephalus.

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