[Ichthyology • 2024] Akarotaxis gouldae • A New Species of Antarctic dragonfish (Perciformes: Notothenioidei: Bathydraconidae) from the western Antarctic Peninsula

Akarotaxis gouldae

Corso, Desvigne, McDowell, Cheng, Biesack, Steinberg & Hilton, 2024

   DOI: 10.11646/zootaxa.5501.2.3

 

Abstract

Bathydraconidae (Notothenioidei) are a group of benthic fishes endemic to the Southern Ocean. Because of their recent evolutionary radiation and limited sampling efforts due to their occurrence in remote regions, their diversity is likely underestimated. Akarotaxis nudiceps, currently the only recognized member of its genus, is an especially poorly known bathydraconid. Although A. nudiceps has a circumpolar distribution on the Antarctic continental shelf, its deep habitat and rarity limit knowledge of its life history and biology. Using a combination of morphological and genetic analyses, we identified an undescribed species of this genus, herein named Akarotaxis gouldae sp. nov. (Banded Dragonfish). The separation of this species was initially identified from archived larval specimens, highlighting the importance of early life stage taxonomy and natural history collections. All currently known adult and larval A. gouldae sp. nov. specimens have been collected from a restricted ~400 km coastal section of the western Antarctic Peninsula, although this is possibly due to sampling bias. This region is targeted by the epipelagic Antarctic krill fishery, which could potentially capture larval fishes as bycatch. Due to the extremely low fecundity of A. gouldae sp. nov. and near-surface occurrence of larvae, we suggest the growing Antarctic krill fishery could negatively impact this species.

Pisces, Bathydraco ninae, cryonotothenioid, Notothenioid, Bellingshausen Sea, Southern ocean, krill fishing, Antarctica

Adult samples of Akarotaxis gouldae (left) compared to adult samples of Akarotaxis nudiceps (right) show subtle yet distinct morphological differences, including the presence of two bands on the bodies of Akarotaxis gouldae as well as a shorter snouts and jaws.  

Akarotaxis gouldae sp. nov.

 Banded Dragonfish 

Diagnosis. A species of Akarotaxis distinguished from A. nudiceps by the presence of two dark vertical bands of pigment on the body (Figs. 3, 4); larger body depth at the origin of the anal fins (Table 2; Fig. 4); and a shorter snout and jaw length (Figs. 4, 5; Table 2).

Akarotaxis gouldae, a newly discovered species of Antarctic dragonfish, was named in honor of the recently decomissioned Antarctic research supply vessel Laurence M. Gould. Credit: Andrew Corso

Etymology. gouldae, in honor of the U.S. Antarctic research and Supply vessel (ARSV) Laurence M. Gould (LMG); for several decades this vessel has supported Antarctic Science and exploration, including the collection of the holotype and all known paratypes. The name is thus not connected to the Antarctic explorer Laurence M. Gould after which the ARSV LMG was named. Noun; feminine, following maritime tradition of referring to ships as female.

This map shows where larval samples of Akarotaxis gouldae (yellow arrows) were collected along the western Antarctic Peninsula. In comparison, Akarotaxis gouldae appear to have a much more limited range. 

Andrew D. Corso, Thomas Desvigne, Jan R. McDowell, Chi-Hing Christina Cheng, Ellen E. Biesack, Deborah K. Steinberg and  Eric J. Hilton. 2024. Akarotaxis gouldae, A New Species of Antarctic dragonfish (Notothenioidei: Bathydraconidae) from the western Antarctic Peninsula.  Zootaxa. 5501(2); 265-290. DOI: doi.org/10.11646/zootaxa.5501.2.3

 

[Crustacea • 2017] Epimeria of the Southern Ocean with Notes on Their Relatives (Amphipoda, Eusiroidea)

Epimeria (Drakepimeria) loerzae, 
E. (Hoplepimeria) quasimodo & 
E. (Drakepimeria) cyrano 

d'Udekem d'Acoz & Verheye, 2017

NaturalSciences.be  DOI: 10.5852/ejt.2017.359 

Abstract

The present monograph includes general systematic considerations on the family Epimeriidae, a revision of the genus Epimeria Costa in Hope, 1851 in the Southern Ocean, and a shorter account on putatively related eusiroid taxa occurring in Antarctic and sub-Antarctic seas. The former epimeriid genera Actinacanthus Stebbing, 1888 and Paramphithoe Bruzelius, 1859 are transferred to other families, respectively to the Acanthonotozomellidae Coleman & J.L. Barnard, 1991 and the herein re-established Paramphithoidae G.O. Sars, 1883, so that only Epimeria and Uschakoviella Gurjanova, 1955 are retained within the Epimeriidae Boeck, 1871. The genera Apherusa Walker, 1891 and Halirages Boeck, 1891, which are phylogenetically close to Paramphithoe, are also transferred to the Paramphithoidae. The validity of the suborder Senticaudata Lowry & Myers, 2013, which conflicts with traditional and recent concepts of Eusiroidea Stebbing, 1888, is questioned. Eight subgenera are recognized for Antarctic and sub-Antarctic species of the genus Epimeria: Drakepimeria subgen. nov., Epimeriella K.H. Barnard, 1930, Hoplepimeria subgen. nov., Laevepimeria subgen. nov., Metepimeria Schellenberg, 1931, Pseudepimeria Chevreux, 1912, Subepimeria Bellan-Santini, 1972 and Urepimeria subgen. nov. The type subgenus Epimeria, as currently defined, does not occur in the Southern Ocean. Drakepimeria species are superficially similar to the type species of the genus Epimeria: E. cornigera (Fabricius, 1779), but they are phylogenetically unrelated and substantial morphological differences are obvious at a finer level. Twenty-seven new Antarctic Epimeria species are described herein: Epimeria (Drakepimeria) acanthochelon subgen. et sp. nov., E. (D.) anguloce subgen. et sp. nov., E. (D.) colemani subgen. et sp. nov., E. (D.) corbariae subgen. et sp. nov., E. (D.) cyrano subgen. et sp. nov., E. (D.) havermansiana subgen. et sp. nov., E. (D.) leukhoplites subgen. et sp. nov., E. (D.) loerzae subgen. et sp. nov., E. (D.) pandora subgen. et sp. nov., E. (D.) pyrodrakon subgen. et sp. nov., E. (D.) robertiana subgen. et sp. nov., Epimeria (Epimeriella) atalanta sp. nov., Epimeria (Hoplepimeria) cyphorachis subgen. et sp. nov., E. (H.) gargantua subgen. et sp. nov., E. (H.) linseae subgen. et sp. nov., E. (H.) quasimodo subgen. et sp. nov., E. (H.) xesta subgen. et sp. nov., Epimeria (Laevepimeria) anodon subgen. et sp. nov., E. (L.) cinderella subgen. et sp. nov., Epimeria (Pseudepimeria) amoenitas sp. nov., E. (P.) callista sp. nov., E. (P.) debroyeri sp. nov., E. (P.) kharieis sp. nov., Epimeria (Subepimeria) adeliae sp. nov., E. (S.) iota sp. nov., E. (S.) teres sp. nov. and E. (S.) urvillei sp. nov. The type specimens of E. (D.) macrodonta Walker, 1906, E. (D.) similis Chevreux, 1912, E. (H.) georgiana Schellenberg, 1931 and E. (H.) inermis Walker, 1903 are re-described and illustrated. Besides the monographic treatment of Epimeriidae from the Southern Ocean, a brief overview and identification keys are given for their putative and potential relatives from the same ocean, i.e., the Antarctic and sub-Antarctic members of the following eusiroid families: Acanthonotozomellidae Coleman & J.L. Barnard, 1991, Dikwidae Coleman & J.L. Barnard, 1991, Stilipedidae Holmes, 1908 and Vicmusiidae Just, 1990. This overview revealed the existence of a new large and characteristic species of Alexandrella Chevreux, 1911, A. chione sp. nov. but also shows that the taxonomy of that genus remains poorly known and that several ‘variable widespread eurybathic species’ probably are species complexes. Furthermore, the genera Bathypanoploea Schellenberg, 1939 and Astyroides Birstein & Vinogradova, 1960 are considered to be junior synonyms of Alexandrella. Alexandrella mixta Nicholls, 1938 and A. pulchra Ren in Ren & Huang, 1991 are re-established herein, as valid species. It is pointed out that this insufficient taxonomic knowledge of Antarctic amphipods impedes ecological and biogeographical studies requiring precise identifications. Stacking photography was used for the first time to provide iconographic support in amphipod taxonomy, and proves to be a rapid and efficient illustration method for large tridimensionally geometric species. A combined morphological and molecular approach was used whenever possible for distinguishing Epimeria species, which were often very similar (albeit never truly cryptic) and sometimes exhibited allometric and individual variations. However in several cases, taxa were characterized by morphology only, whenever the specimens available for study were inappropriately fixed or when no sequences could be obtained. A large number of Epimeria species, formerly considered as eurybathic and widely distributed, proved to be complexes of species, with a narrower (overlapping or not) distribution. The distributional range of Antarctic Epimeria is very variable from species to species. Current knowledge indicates that some species from the Scotia Arc and the tip of the Antarctic Peninsula are narrow range endemics, sometimes confined to one island, archipelago, or ridge (South Georgia, South Orkney Islands, Elephant Island or Bruce Ridge); other species have a distribution encompassing a broader region, such as the eastern shelf of the Weddell Sea, or extending from the eastern shelf of the Weddell Sea to Adélie Coast. The most widely distributed species are E. (D.) colemani subgen. et sp. nov., E. (E.) macronyx (Walker, 1906), E. (H.) inermis Walker, 1903 and E. (L.) walkeri (K.H. Barnard, 1930), which have been recorded from the Antarctic Peninsula/South Shetland Islands area to the western Ross Sea. Since restricted distributions are common among Antarctic and sub-Antarctic Epimeria, additional new species might be expected in areas such as the Kerguelen Plateau, eastern Ross Sea, Amundsen Sea and the Bellingshausen Sea or isolated seamounts and ridges, where there are currently no Epimeria recorded. The limited distribution of many Epimeria species of the Southern Ocean is presumably related to the poor dispersal capacity in most species of the genus. Indeed with the exception of the pelagic and semi-pelagic species of the subgenus Epimeriella, they are heavy strictly benthic organisms without larval stages, and they have no exceptional level of eurybathy for Antarctic amphipods. Therefore, stretches deeper than 1000 m seem to be efficient geographical barriers for many Epimeria species, but other isolating factors (e.g., large stretches poor in epifauna) might also be at play. The existence of endemic shelf species with limited dispersal capacities in the Southern Ocean (like many Epimeria) suggests the existence of multiple ice-free shelf or upper slope refugia during the Pleistocene glaciations within the distributional and bathymetric range of these species. Genera with narrow range endemics like Epimeria would be excellent model taxa for locating hotspots of Antarctic endemism, and thus potentially play a role in proposing meaningful Marine Protected Areas (MPAs) in the Southern Ocean.

Keywords: Alexandrella; Amphipoda; Epimeria; Eusiroidea; Senticaudata; Southern Ocean

Cédric d'Udekem d'Acoz and Marie L. Verheye. 2017. Epimeria of the Southern Ocean with Notes on Their Relatives (Crustacea, Amphipoda, Eusiroidea).  European Journal of Taxonomy. 359;  1–553.  DOI: 10.5852/ejt.2017.359

28 New Amphipod Species Discovered in Antarctica  NaturalSciences.be/en/news/item/9067    via @RBINSmuseum

 facebook.com/museumdino/posts/10155677130305903

[Paleontology • 2017] Kaikaifilu hervei • A New Large Mosasaur (Squamata, Mosasauridae) from the upper Maastrichtian of Antarctica

Kaikaifilu hervei 

Otero, Soto-Acuña, Rubilar-Rogers & Gutstein, 2017  

DOI:  10.1016/j.cretres.2016.11.002 

Highlights

• A new mosasaur from Antarctica.

• The second skull known in the continent.

• A new genus and species of a large austral mosasaur.

Abstract

We present a large, fragmentary skull and the humerus of a mosasaur (Squamata, Mosasauroidea) recovered from upper Maastrichtian beds of the López de Bertodano Formation in Marambio (=Seymour) Island, Antarctica. The material belongs to a large, adult individual with marked heterodonty as well as unusual humeral features. Different phylogenetic analyses returned the studied specimen within the Tylosaurinae, while the unique features of the skull and humerus allow distinguish it from the unique Antarctic known tylosaurine species, Taniwhasaurus antarcticus (Novas et al., 2002), as well as from other known Late Cretaceous mosasaurids from the Southern Hemisphere, thus, justifying the erection of a new taxon, Kaikaifilu hervei gen. et. sp. nov. The different dental types documented in the specimen studied have been previously recorded through isolated teeth from the same locality and were subsequently referred to several genera. This new find and its importance to comprehend the previously known fragmentary records strongly suggests that the diversity of Antarctic mosasaurids could be more reduced than previously interpreted, including taxa which are different to the genera and species from the Northern Hemisphere. The new material represents the youngest occurrence of tylosaurines in Antarctica.

Keywords: Marine reptiles; Mosasaurs; Upper Cretaceous; Marambio Island; Antarctic Peninsula

 Systematic paleontology

Squamata Oppel, 1811

Mosasauridae Gervais, 1853

Russellosaurina Polcyn and Bell, 2005

Tylosaurinae Williston, 1897

Kaikaifilu gen. nov.

Tylosaurinae indet.: In Otero, 2012.

Tylosaurinae gen. et sp. nov.: Otero et al., 2015

Type species: as for the only known species within the genus, Kaikaifilu hervei sp. nov., below.

Derivation of name. From the Mapudungun language of the ancient people of southern South America. From the Mapuche cosmology, Kai-Kai filú is the almighty giant reptile owner of the seas, rival of Treng-Treng filú, both creators of the lands through their continuous fight that causes the earthquakes, volcanoes, tsunamis and all the events that molded the earth where we live (pronunciation: Khai-khai feelóo).

Kaikaifilu hervei sp. nov.

Holotype. SGO.PV.6509. Fragmentary skull preserved in several blocks, including part of the maxillae and the premaxillar, frontal, prefrontals, part of the parietal, partial cast of the braincase, cast of the right orbit, a portion of the right pterygoid, a partial cast of the meckellian canal of one dentary, near 30 isolated teeth, fragments of the mandible, and the proximal part of the left humerus.

Type Locality. Marambio Island, Antarctica, about 1500 m south from the López de Bertodano Bay.

Horizon and Age. López de Bertodano Formation, Klb9 sensu Macellari (1988), Manumiella bertodano Interval Zone ( Bowman et al., 2012) and Pachydiscus riccardi Zone ( Olivero, 2012), upper Maastrichtian.

Derivation of the name. Honoring Dr. Francisco Hervé, Chilean geologist, for their major contribution to the knowledge of the geology of Chile and Antarctic Peninsula.

Diagnosis. Specimen with the following unique combination of characters: Presence of a prominent lateral process anterior to the orbits, conformed by the posterior end of the prefrontal and the anterior end of the postorbitofrontal; well-marked heterodonty including both faceted and non-faceted functional teeth with very soft striations; articular head of the humerus very thick dorsoventrally; K. hervei differs from other mosasaurids from the WBP in the following features: it differs from Tylosaurus (‘Leiodon’) haumuriensis and from the genus Taniwhasaurus (Ta. antarcticus, Ta. oweni and Ta. mikasaensis) by possessing a well-marked heterodonty, condition absent in the two latter genera; it also differs from these taxa on the frontal midline forming an internarial process which is absent in Ta. mikasaensis (premaxillar extends far beyond external naris) and seems to be absent in Ta. antarcticus; K. hervei differs from Moanasaurus mangahouangae in the outline of the frontal which is axially shorter in the latter and without anterolateral concave margins; K. hervei also differs from Rikisaurus tehoensis in having a frontal contacting the pineal foramen, and by the possession of a preorbital constriction of the rostrum. Unique known specimen here referred to K. hervei comprises the largest known skull of a mosasauroid from the Southern Hemisphere.

Conclusions

SGO.PV.6509 comprises a fragmentary skull and fragmentary humerus of a single specimen recovered from upper Maastrichtian levels (lower Klb9 unit) of the López de Bertodano Formation in Marambio Island, Antarctica. This is here identified as a large mosasaurid with prominent anterorbital processes, an axially elongated and triangular frontal that extends between the external naris, a well-marked heterodonty and a dorsoventrally massive humerus. Morphological features of SGO.PV.6509 differ from all known mosasaurids from the Southern Hemisphere and especially from the better known austral tylosaurine, Taniwhasaurus antarticus. Thus, a new genus and species, Kaikaifilu hervei, is proposed here. This new skull from the upper Mastrichtian of Antarctica represents the best evidence on the presence of very large tylosaurines on high latitudes (65°) of the Southern Hemisphere prior to the K/Pg boundary. Previous to this research, this clade remained poorly documented in high latitudes. The marked heterodonty of SGO.PV.6509 suggest that several taxa previously reported from the Upper Cretaceous of Antarctica and based on isolated teeth, should be reviewed under the new evidence, since most of them appear to match with the different dental types of the specimen here described.

 Rodrigo A. Otero, Sergio Soto-Acuña, David Rubilar-Rogers and Carolina S. Gutstein. 2017. Kaikaifilu hervei gen. et sp. nov., A New Large Mosasaur (Squamata, Mosasauridae) from the upper Maastrichtian of Antarctica. Cretaceous Research. In Press.  DOI:  10.1016/j.cretres.2016.11.002

[Paleontology • 2014] Latest Cretaceous–earliest Paleogene Vegetation and Climate Change at the High Southern Latitudes: Palynological Evidence from Seymour Island, Antarctic Peninsula

Fig. 7. Artist's impression of the eastern flank of the Antarctic Peninsula during the Maastrichtian. The vegetation composition and habitat types are based on the nearest living relatives of the terrestrial palynoflora from Seymour Island discussed in this paper. Mixed temperate rainforest grew in the lowlands to mid altitudes composed mainly of a Nothofagus–podocarp–Proteaceae canopy with Lagarastrobus (Tasmanian Huon Pine) occupying the super-wet habitats along riverine margins. Freshwater pools hosted aquatic ferns and green algae with bordering wetlands filled with diverse mosses and ferns. At higher altitudes, open heath-like vegetation may have grown beyond the tree line of montane araucarian forests (detailed in Fig. 8). All fauna are known from the Cretaceous fossil record of the James Ross Basin

( Chatterjee, 1989, Chatterjee, 2002, Case et al., 2000, Case et al., 2003, Case et al., 2007, Clarke et al., 2005, Salgado and Gasparini, 2006, Cerda et al., 2012 and Coria et al., 2013). Artist: James McKay, University of Leeds.  DOI: 10.1016/j.palaeo.2014.04.018

Highlights

• First quantitative vegetation analysis for the Antarctic during the Maastrichtian

• Terrestrial palynology suggests a temperate rainforest on the Antarctic Peninsula.

• Floral trends were influenced by concurrent changes in temperature and humidity.

• Cool, humid conditions gave way to a warmer climate ~ 2 myr before the K–Pg event.

Abstract

Fluctuations in Late Cretaceous climate were already influencing biotic change prior to the environmental upheaval at the Cretaceous–Paleogene (K–Pg) boundary, but their general nature, magnitude and timing remain controversial. A high-resolution dataset on terrestrially-derived palynomorphs is presented from the high southern palaeolatitudes that unlocks details of small-scale climate variability throughout this period of significant global change. Specifically, this is a quantitative spore and pollen analysis of an expanded uppermost Cretaceous to lowermost Paleogene (Maastrichtian–earliest Danian) shallow marine sedimentary succession from Seymour Island, off the northeastern tip of the Antarctic Peninsula, then (as now) located at ~ 65°S. Using nearest living relatives the first detailed vegetation, habitat and climate reconstruction is presented for the emergent volcanic arc at this time. On the coastal lowlands, a cool to warm temperate rainforest is envisaged growing in a riverine landscape, with both wet (river margin, pond) and relatively dry (interfluve, canopy gap) habitats. Diverse podocarps and southern beech trees grew alongside angiosperm herbs and shrubs in mean annual temperatures of ~ 10–15 °C. Higher altitude araucarian forests gave way to open ericaceous heathland, beyond the tree line, in subalpine to alpine conditions with mean annual temperatures of a cold ~ 5–8 °C. There is no exact modern botanical equivalent, but the closest modern flora is that of the Andes of southern Chile and Argentina. Maastrichtian climate is shown to have fluctuated from cool, humid conditions, through a rapid warming ~ 2 million years prior to the K–Pg transition, followed by cooling during the earliest Danian, a trend supported by previous work on this interval.

Keywords: Late Cretaceous; Paleogene; Pollen; Palaeoclimate; Palaeoecology; Antarctica

Vanessa C. Bowman, Jane E. Francis, Rosemary A. Askin, James B. Riding and Graeme T. Swindles. 2014.  Latest Cretaceous–earliest Paleogene Vegetation and Climate Change at the High Southern Latitudes: Palynological Evidence from Seymour Island, Antarctic Peninsula. Palaeogeography, Palaeoclimatology, Palaeoecology. 408(15); 26–47.  DOI: 10.1016/j.palaeo.2014.04.018

http://www.lifeandplanet.net/uploads/8/6/7/2/8672988/bowman_et_al_2014.pdf

Understanding Earth’s response to a future high CO2 world

https://www.bas.ac.uk/team/science-teams/palaeo-environments-or-past-climates/understanding-earths-response-to-a-future-high-co2-world/

https://paleonerdish.wordpress.com/2014/09/30/a-brief-introduction-to-dinosaur-herbivory/

[PaleoMammalogy • 2014] Notiolofos cf. arquinotiensis • The Oldest Mammals from Antarctica, early Eocene of the La Meseta Formation, Seymour Island

Figure 1. Geographical and stratigraphical provenance of the remains described here.
Figure 2. View of the north-west side of the Seymour Island. The arrow indicates the position of locality IAA 1/13.

Abstract

New fossil mammals found at the base of Acantilados II Allomember of the La Meseta Formation, from the early Eocene (Ypresian) of Seymour Island, represent the oldest evidence of this group in Antarctica. Two specimens are here described; the first belongs to a talonid portion of a lower right molar assigned to the sparnotheriodontid litoptern Notiolofos sp. cf. N. arquinotiensis. Sparnotheriodontid were medium- to large-sized ungulates, with a wide distribution in the Eocene of South America and Antarctica. The second specimen is an intermediate phalanx referred to an indeterminate Eutheria, probably a South American native ungulate. These Antarctic findings in sediments of 55.3 Ma query the minimum age needed for terrestrial mammals to spread from South America to Antarctica, which should have occurred before the final break-up of Gondwana. This event involves the disappearance of the land bridge formed by the Weddellian Isthmus, which connected West Antarctica and southern South America from the Late Cretaceous until sometime in the earliest Palaeogene.

Keywords: West Antarctica; Palaeogene; Ypresian; tooth and bone morphology; ungulates; Sparnotheriodontidae

Class MAMMALIA Linnaeus, 1758

Order LITOPTERNA Ameghino, 1889

Family SPARNOTHERIODONTIDAE Soria, 1980

Genus NOTIOLOFOS Bond, Reguero, Vizcaíno, Marenssi and Ortiz Jaureguizar, 2009

Type species: Notiolofos arquinotiensis (Bond, Reguero, Vizcaíno and Marenssi, 2006).

Notiolofos cf. N. arquinotiensis (Bond, Reguero, Vizcaíno and Marenssi, 2006)  

 Javier N. Gelfo, Thomas Mörs, Malena Lorente, Guillermo M. López, Marcelo Reguero. in press. The Oldest Mammals from Antarctica, early Eocene of the La Meseta Formation, Seymour Island. Palaeontology. doi: dx.doi.org/10.1111/pala.12121.

Bond, M., Reguero, M. A., Vizcaíno, S. F. and Ortiz-Jaureguizar, E. 2009. Notiolofos, a replacement name for Notolophus Bond, Reguero, Vizcaíno and Marenssi, 2006, a preoccupied name. Journal of Vertebrate Paleontology. 29, 979.

http://www.tandfonline.com/doi/abs/10.1671/039.029.0321

M. Bond, M. A. Reguero, S. F. Vizcaíno and S. A. Marenssi. 2006. A New ‘South American ungulate’ (Mammalia: Litopterna) from the Eocene of the Antarctic Peninsula. In J. E. Francis, D. Pirrie, J. A. Crame (eds). Cretaceous-tertiary high-latitude palaeoenvironments: James Ross Basin, Antarctica. The Geological Society of London. 258(1): 163–176. doi: dx.doi.org/10.1144/GSL.SP.2006.258.01.12.

researchgate.net/publication/249551916_A_new_'South_American_ungulate'_(Mammalia_Litopterna)_from_the_Eocene_of_the_Antarctic_Peninsula

[PaleoMammalogy • 2006] Notiolofos (Notolophus) arquinotiensis • A New ‘South American ungulate’ (Mammalia: Litopterna) from the Eocene of the Antarctic Peninsula

Abstract

Notolophus arquinotiensis, a new genus and species of the family Sparnotheriodontidae (Mammalia, Litopterna), is represented by several isolated teeth from the shallow-marine sediments of the La Meseta Formation (late Early-Late Eocene) of Seymour Island, Antarctic Peninsula, which have also yielded the youngest known sudamericids and marsupials. The new taxon belongs to the extinct order of ‘South American native ungulate’ Litopterna characterized by the convergence of the later forms with the equids and camelids. Notolophus arquinotiensis shows closest relationships with Victorlemoinea from the Itaboraian (middle Palaeocene) of Brazil and Riochican-Vacan (late Palaeocene-early Eocene) of Patagonia, Argentina. Although still poorly documented, this new taxon shows that the early Palaeogene Antarctic faunas might provide key data concerning the problems of the origin, diversity and basal phylogeny of some of the ‘South American ungulates’ (Litopterna). This new taxon shows the importance of Antarctica in the early evolution of the ungulates and illustrates our poor state of knowledge.

M. Bond, M. A. Reguero, S. F. Vizcaíno and S. A. Marenssi. 2006. A New ‘South American ungulate’ (Mammalia: Litopterna) from the Eocene of the Antarctic Peninsula. In J. E. Francis, D. Pirrie, J. A. Crame (eds). Cretaceous-tertiary high-latitude palaeoenvironments: James Ross Basin, Antarctica. The Geological Society of London. 258(1): 163–176. doi: dx.doi.org/10.1144/GSL.SP.2006.258.01.12.

researchgate.net/publication/249551916_A_new_'South_American_ungulate'_(Mammalia_Litopterna)_from_the_Eocene_of_the_Antarctic_Peninsula

Bond, M., Reguero, M. A., Vizcaíno, S. F. and Ortiz-Jaureguizar, E. 2009. Notiolofos, a replacement name for Notolophus Bond, Reguero, Vizcaíno and Marenssi, 2006, a preoccupied name. Journal of Vertebrate Paleontology. 29, 979.

http://www.tandfonline.com/doi/abs/10.1671/039.029.0321

 Javier N. Gelfo, Thomas Mörs, Malena Lorente, Guillermo M. López, Marcelo Reguero.  in press. The oldest mammals from Antarctica, early Eocene of the La Meseta Formation, Seymour Island. Palaeontology. doi: dx.doi.org/10.1111/pala.12121.