[PaleoIchthyology • 2026] New Data on the sarcopterygian Koharalepis jarviki (Tetrapodomorpha: Canowindridae) from the Late Devonian of Antarctica, revealed via Synchrotron and Neutron Tomography

 

Koharalepis jarviki Young & Ritchie, 1992  
3D rendering of Koharalepis jarviki (AMF 54325) from neutron tomographic data.

  in Mensforth, Long, Bevitt et Clement, 2026. 

DOI: doi.org/10.3389/fevo.2026.1765271

Artwork: Thomas Turner

Abstract

Introduction: The ‘osteolepiforms’ are an extinct order of lobe-finned fishes that had a cosmopolitan distribution, which are often considered for their proximity to the vertebrate water-to-land transition. The canowindrids are an East Gondwanan clade of tetrapodomorph fishes that exhibit a high level of endemism. However, due to the rarity of canowindrid material and their taphonomy, there is only a single representative preserved wholly in 3D and thus suitable for investigation via modern non-invasive tomography.

Methods: Here we present an updated description of the holotype of Koharalepis jarviki, a canowindrid collected from the Late Devonian Aztec Siltstone formation in Mt Crean, Antarctica, elucidated via a combination of synchrotron and neutron tomography.

Results and discussion: New elements of the braincase, palate, mandible and axial skeleton are revealed for the first time, and previously reported anatomy including the dermal skull and position of the orbits are confirmed. A partial braincase and endocast has been reconstructed, enabling rare insight into the neural anatomy of Koharalepis. Phylogenetic analysis confirms Koharalepis as a member of the Canowindridae with Harajicadectes zhumini recovered as sister taxon. The canowindrids occupy a region of the phylogenetic tree with ‘osteolepidid’ taxa and megalichthyids, crownward of rhizodonts but below tristichopterids and elpistostegalids. This work provides greater support for the taxonomic characters and phylogenetic position of the enigmatic canowindrid family, and the 3D preservation of this material has enabled us to infer some behavioural and ecological insight.

Keywords: 3D modelling, canowindrid, Devonian, endocast, neutron tomography, phylogenetic analysis, Sarcopterygii, tetrapodomorph

3D rendering of Koharalepis jarviki (AMF 54325) from neutron tomographic data in (A) dorsal view, (B) ventral view, (C) anterior view, (D) left lateral view and (E) posterior view.

Et, extra temporal; Ju, jugal; L.Ex, lateral extrascapular; M.Ex, median extrascapular; Op, operculum; Par, parietal; Po, postorbital; PP, postparietal; Sclm, supracleithrum; Sq, squamosal.

Life reconstruction of the Devonian tetrapodomorph fish Koharalepis jarviki.

Artwork: Thomas Turner/Flinders University

 Koharalepis jarviki Young & Ritchie, 1992

Corinne L. Mensforth, John A. Long, Joseph J. Bevitt and Alice M. Clement. 2026. New Data on the sarcopterygian Koharalepis jarviki (Tetrapodomorpha; Canowindridae) from the Late Devonian of Antarctica, revealed via Synchrotron and Neutron Tomography. Front. Ecol. Evol. (14); DOI: doi.org/10.3389/fevo.2026.1765271 [16 April 2026]

[PaleoOrnithology • 2025] Pujatopouli soberana • Diving in the Maastrichtian of Marambio (Seymour) Island: A New Member of the Neoaves in the Cretaceous Antarctic Avifauna

  

Pujatopouli soberana 

Irazoqui, Hospitaleche, Gelfo, Carabajal, Bona & Burlaille, 2026

DOI: doi.org/10.1016/j.cretres.2025.106259 

facebook.com/CarolinaAcostaHospitaleche 

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Illustration by Samanta Faiad. 

Highlights

• A new genus and species of Cretaceous Neoaves is described.

• Phylogenetic analysis suggests its relationship to Aequornithes.

• A coeval existence of Galloanseres and Neoaves in the Maastrichtian of Marambio Island is postulated.

• The López de Bertodano Formation is the only lithostratigraphic showing a high diversity of Cretaceous Neornithes.

• This avifauna is characterized by the predominance of foot-propelled diving birds.

Abstract

A new genus and species of Cretaceous bird from Antarctica with implications for the early evolution of Neornithes is described here. The type specimen of Pujatopouli soberana gen. et sp. nov. (MLP-PV 08-XI-30-44), preserving part of the skull and postcranium, was recovered from Maastrichtian deposits of the López de Bertodano Formation on Marambio (Seymour) Island, James Ross Basin, West Antarctica. The phylogenetic relationships of Pujatopouli with other avian species, including all previously described Cretaceous birds from Antarctica, were assessed using two different datasets. The first, mainly composed of Mesozoic birds, places Pujatopouli within the crown group of birds (Neornithes), whereas the second, which includes a broad sampling of modern taxa, positions it within Neoaves, and closely related to the ‘core-waterbirds’ (Aequornithes). Besides, morphological evidence suggests that Pujatopouli was a foot-propelled diver with an ichthyophagous diet, living sympatrically with other neornithine birds along the Antarctic coast during the latest Cretaceous.

Systematic palaeontology

AVES Linnaeus, 1758.

ORNITHURAE Haeckel, 1866.

NEORNITHES Gadow (1892).

NEOGNATHAE Pycraft, 1900.

NEOAVES Sibley et al., 1988.

AEQUORNITHES Mayr (2011).

 

Pujatopouli gen nov. 

 

Pujatopouli soberana sp. nov.

 

Pujatopouli soberana nov. gen. et sp., swimming in the Antarctic waters of the Maastrichtian.

Illustration by Samanta Faiad. 

 

Facundo Irazoqui, Carolina Acosta Hospitaleche, Javier N. Gelfo, Ariana Paulina Carabajal, Paula Bona and Leonel Acosta Burlaille. 2026. Diving in the Maastrichtian of Marambio (Seymour) Island: A New Member of the Neoaves in the Cretaceous Antarctic Avifauna. Cretaceous Research. 179; 106259. DOI: doi.org/10.1016/j.cretres.2025.106259

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https://acostacaro.wixsite.com/acostahospitaleche/publications

[PaleoOrnithology • 2025] Vegavis iaai • Cretaceous Antarctic Bird Skull elucidates early Avian Ecological Diversity

 Vegavis iaai  Clarke et al., 2005

in Torres, Clarke, Groenke, Lamanna, MacPhee, Musser, Roberts et O’Connor, 2025.

DOI: doi.org/10.1038/s41586-024-08390-0  

Artwork: Mark Witton

Abstract

Fossils representing Cretaceous lineages of crown clade birds (Aves) are exceptionally rare but are crucial to elucidating major ecological shifts across early avian divergences. Among the earliest known putative crown birds is Vegavis iaai, a foot-propelled diver from the latest Cretaceous (69.2–68.4 million years ago)6 of Antarctica with controversial phylogenetic affinities. Initially recovered by phylogenetic analyses as a stem anatid (ducks and closely related species), Vegavis has since been recovered as a stem member of Anseriformes (waterfowl), or outside Aves altogether10. Here we report a new, nearly complete skull of Vegavis that provides new insight into its feeding ecology and exhibits morphologies that support placement among waterfowl within crown-group birds. Vegavis has an avian beak (absence of teeth and reduced maxilla) and brain shape (hyperinflated cerebrum and ventrally shifted optic lobes). The temporal fossa is well excavated and expansive, indicating that this bird had hypertrophied jaw musculature. The beak is narrow and pointed, and the mandible lacks retroarticular processes. Together, these features comprise a feeding apparatus unlike that of any other known anseriform but like that of other extant birds that capture prey underwater (for example, grebes and loons). The Cretaceous occurrence of Vegavis, with a feeding ecology unique among known Galloanserae (waterfowl and landfowl), is further indication that the earliest anseriform divergences were marked by evolutionary experiments unrepresented in the extant diversity.

Digital reconstruction of the Late Cretaceous (~69 million years old) crown bird Vegavis iaai that was completed following high-resolution micro-computed tomography of a fossil-bearing concretion discovered on Vega Island, Antarctic Peninsula.

Credit: Joseph Groenke and Christopher Torres. 

The Late Cretaceous modern (crown) bird, Vegavis iaai, pursuit diving for fish in the shallow ocean off the coast of the Antarctic peninsula, with ammonites and plesiosaurs for company.

Artwork: Mark Witton, 2025.

 

Christopher R. Torres, Julia A. Clarke, Joseph R. Groenke, Matthew C. Lamanna, Ross D. E. MacPhee, Grace M. Musser, Eric M. Roberts and Patrick M. O’Connor. 2025. Cretaceous Antarctic Bird Skull elucidates early Avian Ecological Diversity. Nature. 638; 146–151. DOI: doi.org/10.1038/s41586-024-08390-0  

[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

 

[Invertebrate • 2023] Promachocrinus fragarius, P. unruhi, etc. • Resolving the Taxonomy of the Antarctic Feather Star Species Complex Promachocrinus ‘kerguelensis’ (Echinodermata: Crinoidea)

Promachocrinus sp.

 McLaughlin, Wilson & Rouse, 2023

DOI: 10.1071/IS22057

  twitter.com/NeridaWilson

Abstract

An increasing number of Antarctic invertebrate taxa have been revealed as cryptic species complexes following DNA-based assessments. This ultimately necessitates a morphological reassessment to find traits that will help identify these cryptic or pseudocryptic species without the need for sequencing every individual. This work concerns comatulid crinoid echinoderms long considered to represent a single, circum-Antarctic species, Promachocrinus kerguelensis. The first molecular studies sought to distinguish the diversity in the complex and understand the constituent species distributions but stopped short of formal taxonomic assessment. Here, we continued to increase sample representation around the Southern Ocean and sequenced the mitochondrial COI gene for all new specimens, and additional genes for a few representatives. We also elucidated previously unappreciated features, particularly body pigmentation and morphology of the centrodorsal ossicle in an attempt to diagnose some species morphologically and based on DNA data. The species complex within Promachocrinus is here resolved into P. kerguelensis Carpenter, 1879, P. vanhoeffenianus Minckert, 1905, P. joubini Vaney, 1910, P. mawsoni (Clark, 1937) comb. nov. (transferred from Florometra) and four previously unnamed species, P. fragarius sp. nov., P. unruhi sp. nov., P. uskglassi sp. nov. and P. wattsorum sp. nov. Although most species can be distinguished morphologically, several cannot be reliably separated without DNA data. All sequenced species are essentially circum-Antarctic, with the notable exception of P. wattsorum sp. nov. that is restricted to the Prince Edward Islands in the sub-Antarctic Indian Ocean and P. vanhoeffenianus that is only known from the type locality in the Davis Sea. The vast nature of the Antarctic and Southern Ocean ecosystem dictates large scale sampling to understand the full extent of the biodiversity.

 

Keywords: Antarctica, Crinoidea, cryptic species, Echinodermata, feather star, phylogeny, species delineation, taxonomy.

  

Emily L. McLaughlin, Nerida G. Wilson and Greg W. Rouse. 2023. Resolving the Taxonomy of the Antarctic Feather Star Species Complex Promachocrinus ‘kerguelensis’ (Echinodermata: Crinoidea). Invertebrate Systematics. 37(7); 498-527. DOI: 10.1071/IS22057 

 twitter.com/NeridaWilson/status/1680491072173248513

The Antarctic feather star Promachocrinus kerguelensis arguably comprises several species but taxonomic revision has not been attempted. Here we use DNA data and morphological characters to differentiate the species and formally described those that are new. The species complex was resolved into eight species, four of which are newly described, though not all can be reliably distinguished based on morphology. One of the new species has a restricted distribution, but the remainder appear to be circum-Antarctic.

[Paleontology • 2023] Rhigerpeton isbelli • A New lapillopsid from Antarctica and A Reappraisal of the Phylogenetic Relationships of early Diverging stereospondyls (Temnospondyli: Stereospondyli: Lapillopsidae)

Rhigerpeton isbelli

Gee, Beightol & Sidor, 2023

 DOI: 10.1080/02724634.2023.2216260 

 twitter.com/ChristianSidor 

 twitter.com/Koskinonodon 

ABSTRACT

Stereospondyls underwent a global radiation in the Early Triassic, including an abundance of small-bodied taxa, which are otherwise rare throughout the Mesozoic. Lapillopsidae is one such clade and is presently known only from Australia and India. This clade’s phylogenetic position, initially interpreted as micropholid dissorophoids and later as early diverging stereospondyls, remains uncertain. Although the latter interpretation is now widely accepted, lapillopsids’ specific relationship to other Early Triassic clades remains unresolved; in particular, recent work suggested that Lapillopsidae nests within Lydekkerinidae. Here we describe Rhigerpeton isbelli, gen. et sp. nov., based on a partial skull from the lower Fremouw Formation of Antarctica that is diagnosed by a combination of features shared with at least some lapillopsids, such as a longitudinal ridge on the dorsal surface of the tabular, and features not found in lapillopsids but shared with some lydekkerinids, such as the retention of pterygoid denticles and a parachoanal tooth row (as in Lydekkerina, for example). A series of phylogenetic analyses confirm the lapillopsid affinities of R. isbelli but provide conflicting results regarding the polyphyly and/or paraphyly of Lydekkerinidae with respect to lapillopsids. The position of Lapillopsidae within Temnospondyli is highly sensitive to taxon sampling of other predominantly Early Triassic temnospondyls. The occurrence of a lapillopsid in Antarctica brings the documented temnospondyl diversity more in line with historically well-sampled portions of southern Pangea, but robust biogeographic comparisons remain hindered by the inability to resolve many historic Antarctic temnospondyl records to the finer taxonomic scales needed for robust biostratigraphy.

Rhigerpeton isbelli, gen. et sp. nov.

 

 

Bryan M. Gee, Charles V. Beightol and Christian A. Sidor. 2023. A New lapillopsid from Antarctica and A Reappraisal of the Phylogenetic Relationships of early Diverging stereospondyls. Journal of Vertebrate Paleontology. e2216260. DOI: 10.1080/02724634.2023.2216260

  twitter.com/ChristianSidor/status/1674070112066760705

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[Paleontology • 2022] Ancient Antarctica: the early Evolutionary History of Nothofagus

Nothofagus

in Vento, Agrain & Puebla, 2022. 

DOI: 10.1080/08912963.2022.2150549 

 ResearchGate.net/publication/365900328

 

ABSTRACT

The genus Nothofagus (southern beech) has an extensive fossil record and extant species exclusively distributed in the Southern Hemisphere. It is divided into four subgenera widespread across eastern Australasia and southern South America. The origin and evolution among closely related species remain an important question in palaeontology. The goal of this work is to reconstruct the biogeography of Nothofagus incorporating a complete leaf fossil dataset to better understand its origin, diversification, and colonisation history. The most ancient fossil leaves were discovered in Antarctica and are herein included for the first time into phylogenetic and biogeographic analyses. We employed statistical biogeographic methods implemented in BioGeoBEARS to estimate ancestral areas. The results support a high probability that the ancient ancestor of Nothofagus may have originated in Antarctica during the Late Cretaceous which is also supported by the fossil pollen record found in the Antarctic Peninsula. Subgenera Fuscospora and Lophozonia resulted in the most ancient clades, while the subgenera Nothofagus and Brassospora evolved later (Palaeogene). Our model supports that subgenera divergences were characterised by both dispersal and vicariance events from the Late Cretaceous to the early–middle Eocene.

 

KEYWORDS: Nothofagaceae, fossil, leaves, phylogeny, biogeography, southern beech

 

Bárbara Vento, Federico Agrain and Griselda Puebla. 2022. Ancient Antarctica: the early Evolutionary History of Nothofagus. Historical Biology: An International Journal of Paleobiology. DOI: 10.1080/08912963.2022.2150549  

ResearchGate.net/publication/365900328_the_early_evolutionary_history_of_Nothofagus

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[Cnidaria • 2022] Diplopathes antarctica, D. multipinnata & D. tuatoruensis • New Genus and Species of Black Coral (Anthozoa: Antipatharia: Schizopathidae) from the SW Pacific and Antarctica

Diplopathes sp.

Opresko, Stewart, Voza, Tracey & Brugler, 2022

DOI: 10.11646/zootaxa.5169.1.3 

 twitter.com/BlackCoralLab

Abstract

A new genus, Diplopathes, in the family Schizopathidae, and three new species are described from the Southwest Pacific and Antarctic region based on morphological data. The new genus superficially resembles Telopathes in being branched and having simple, bilateral pinnules, but differs in having strictly alternately arranged pinnules, and in having small polyps 4 mm or less in transverse diameter. Mitochondrial DNA placed Diplopathes and Telopathes in separate clades within the Schizopathidae, thus supporting the significance of seemingly subtle anatomical differences. The new species are: D. antarctica, with sparse branching, pinnules of up to 7 cm long, and polypar spines up to 0.045 mm tall; D. multipinnata, with dense branching, pinnules up to 3 cm long, and polypar spines up to 0.1 mm tall; and D. tuatoruensis, with very sparse branching, pinnules up to 10 cm long, and polypar spines up to 0.1 mm. Interestingly, the three new species do not form a monophyletic clade based on mitochondrial DNA. We propose and discuss two hypotheses to explain the results of the phylogenetic reconstruction, including that molecular and physical change are uncoupled or that we have uncovered another example of morphological convergence in unrelated species.

 Keywords: Coelenterata, Morphological convergence, ITS2, mitochondrial DNA, New Zealand, SRP54, taxonomy, Telopathes

 

Dennis M. Opresko, Rob Stewart, Tatiana Voza, Di Tracey and Mercer R. Brugler. 2022. New Genus and Species of Black Coral from the SW Pacific and Antarctica (Cnidaria: Anthozoa: Antipatharia: Schizopathidae). Zootaxa. 5169(1); 31-48. DOI: 10.11646/zootaxa.5169.1.3

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[Crustacea • 2022] Pseudomma kryotroglodytum • First Report of the Order Mysida in Antarctic Marine Ice Caves, with Description of A New Species of Pseudomma and Investigations on the Taxonomy, Morphology and Life Habits of Mysidetes Species

Pseudomma kryotroglodytum

Wittmann & Chevaldonné, 2022

DOI: 10.3897/zookeys.1079.76412

Abstract

SCUBA diving explorations of three islands off Dumont d’Urville Station at the coast of Adélie Land, East Antarctica, enabled the observation of marine ice caves. Sampling in this unusual habitat yielded a total of three species of Mysidae, altogether previously poorly known or unknown to science. Pseudomma kryotroglodytum sp. nov. is described, based on the structure of the antennal scale, telson and on cornea-like lateral portions set off against the main body of eyeplates. Mysidetes illigi is re-established at species level after almost a century in synonymy. Re-descriptions are provided for M. illigi and M. hanseni, based on types and ice cave materials. Keys to the Southern Ocean species of Pseudomma and to the world-wide species of Mysidetes are given.

Phylogenetic trees are provided for the genera Pseudomma and Mysidetes. 18S rDNA sequences of P. kryotroglodytum differ from GenBank sequences of other Pseudomma species. First sequence data are given for species of the genus Mysidetes: 18S differs between the two examined species and COI is quite diverse between and within species.

We found previously unknown, probably sensorial structures in these ice cave species: in P. kryotroglodytum, the basal segment of the antennula shows a pit-like depression with striated pad on the bottom and a median cyst, connected with the bottom of the eyeplate cleft. M. illigi shows a female homologue of the appendix masculina bearing a field of modified setae. Subsequent investigations demonstrated these structures also in species from other habitats.

The feeding apparatus and stomach contents of the three ice cave species point to brushing of small particles (detritus, microalgae) from available surfaces, such as sediment, rock and the ice surface. Differences in the feeding apparatus are very subtle between the two Mysidetes species. The high content of fat bodies in M. hanseni could help it to survive periods of starvation. The large storage volume of the foregut in P. kryotroglodytum points to the collection of food with low nutritional quality and could help to balance strongly fluctuating food availability.

Summer specimens of M. hanseni showed a bimodal frequency of developmental stages in the marsupium and bimodal size-frequency distribution of free-living stages. The females with younger brood (embryos) were, on average, larger and carried more marsupial young than those with older brood (nauplioid larvae). All examined incubating and spent females showed (almost) empty foreguts and empty ovarian tubes, suggesting possible semelparity and death following the release of young. The absence of juveniles and immature females from summer samples suggests that growth and accumulation of fat and yolk occur outside ice caves, while such caves could be used by fattened adults as shelter for brooding. A provisional interpretation proposes a biannual life cycle for M. hanseni, superimposed with shifted breeding schedules, the latter characterised by early breeding and late breeding females, probably in response to harsh physical and trophic conditions along the continental coast of Antarctica.

Keywords: Development, feeding, key to species, life cycle, marine caves, molecular systematics, polar biology, sensory organs

Order Mysida Boas, 1883

Family Mysidae Haworth, 1825

Subfamily Erythropinae Hansen, 1910

Tribe Pseudommini Wittmann, Ariani & Lagardère, 2014

Genus Pseudomma G.O. Sars, 1870

Pseudomma kryotroglodytum sp. nov. from ice cave of Bernard Island, Antarctica
A female holotype, lateral B cephalothorax of female holotype, dorsal C physical aspect of the ice cave environmentA, B living specimen in laboratory.

Pseudomma kryotroglodytum sp. nov. 

  

Diagnosis: Covers females only. Species of the genus Pseudomma G.O. Sars, 1870, with cornea-like lateral portions separated by sulci from main part of eyeplate (Figs 2B, 4C, 23A), no visual elements. Disto-median fissure penetrates one third of eyeplate. Distal margin of eyeplates with series of minute teeth along sublateral sector (‘shoulders’, Fig. 23A, D). Basal segment of antennular trunk without medio-ventral carina. Antennal scale (Fig. 4B) with setose apical lobe contributing about 1/4 scale length. Mandibular palp (Fig. 4E) 3-segmented, very large, about as long as antennal scale. Three pairs of oostegites (Fig. 5I) contributing to wall of brood pouch. Pleopods (Fig. 6H–L) reduced to setose rods with residual differentiation of endopod (pseudobranchial lobes). Telson (Figs 3A, 6N) trapezoid, as long as ultimate pleonite. Its length twice maximum width at basis and four times width at apex. Lateral margins of telson without setae and spines, only minute scales present. Transversely truncate terminal margin with only two pairs of spines, both hispid due to minute scales (Fig. 3B) along more than proximal 2/3 spine length. Large latero-apical and same-sized submedio-apical spines flank median pair of closely set setae (Fig. 3C) with twice spine length. Margin with short, well-rounded indentation between each spine, median indentation largest. Disto-lateral edge without tooth, with spine only.

Etymology: The species name is an adjective with Latinised neutral ending formed by adjectivation of the amalgamated Ancient Greek adjective κρύος (cold) with the noun τρωγλοδύτης (cave dweller). The adjectivation has precedence in the name of the butterfly Macroglossum troglodytus Boisduval, l875, listed by Kemal et al. (2019) as M. troglodytum.

 

 Karl J. Wittmann and Pierre Chevaldonné. 2022. First Report of the Order Mysida (Crustacea) in Antarctic Marine Ice Caves, with Description of A New Species of Pseudomma and Investigations on the Taxonomy, Morphology and Life Habits of Mysidetes Species. ZooKeys. 1079: 145-227.  DOI: 10.3897/zookeys.1079.76412

[Ornithology • 2020] Morphometric and Genetic Evidence for Four Species of Gentoo Penguin; Pygoscelis papua, P. ellsworthi, P. taeniata & P. poncetii

 

South Georgia Gentoo Penguins Pygoscelis poncetii

Tyler, Bonfitto, Clucas, Reddy & Younger, 2020

DOI: 10.1002/ece3.6973  

 twitter.com/JoshTylerEarth 

 twitter.com/Jane_Younger 

  Photo by Gemma Clucas

Abstract

Gentoo penguins (Pygoscelis papua) are found across the Southern Ocean with a circumpolar distribution and notable genetic and morphological variation across their geographic range. Whether this geographic variation represents species‐level diversity has yet to be investigated in an integrative taxonomic framework. Here, we show that four distinct populations of gentoo penguins (Iles Kerguelen, Falkland Islands, South Georgia, and South Shetlands/Western Antarctic Peninsula) are genetically and morphologically distinct from one another. We present here a revised taxonomic treatment including formal nomenclatural changes. We suggest the designation of four species of gentoo penguin: Pygoscelis papua in the Falkland Islands, P. ellsworthi in the South Shetland Islands/Western Antarctic Peninsula, P. taeniata in Iles Kerguelen, and a new gentoo species P. poncetii, described herein, in South Georgia. These findings of cryptic diversity add to many other such findings across the avian tree of life in recent years. Our results further highlight the importance of reassessing species boundaries as methodological advances are made, particularly for taxa of conservation concern. We recommend reassessment by the IUCN of each species, particularly P. taeniata and P. poncetii, which both show evidence of decline.

Keywords: Antarctica, integrative taxonomy, new species, Pygoscelis, Southern Ocean

South Georgia Gentoo penguins (Pygoscelis poncetii) live in more northerly habitats where conditions are milder, than their Southern Gentoo cousins, which live on the Antarctic ice.

  Photo by Gemma Clucas

  Pygoscelis poncetii sp. nov.

Common Name. South Georgia gentoo penguin.

 

Etymology. Pygoscelis poncetii is named after Sally Poncet, whose body of work has significantly influenced the field of polar biology, particularly in relation to South Georgia.

Diagnosis. Morphologically, P. poncetii can be differentiated from all other species of gentoo by its manus length (mean length = 130.49 mm), being significantly smaller than P. papua (mean length = 135.08 mm, p = .0292) and significantly larger than both P. ellsworthi and P. taeniata (mean lengths = 115.38 mm and 125.27 mm, p < .0001 and p = .0232, respectively). Radius length differentiates P. poncetii (mean length = 52.68 mm) from the larger P. papua (mean length = 58.11 mm, p = .0003) and smaller P. ellsworthi (mean length = 48.90 mm, p = .0039). Genetic comparative techniques (Pairwise FST, heterozygosity, clustering methods) found significant differences among all four species of gentoo penguin with the maximum likelihood phylogeny resolving each species as 100% supported. There are no discernible differences in plumage patterns among the four species.

CONCLUDING REMARKS: 

In this paper, we highlight hidden biodiversity within the species P. papua using genetic and morphometric methods, in keeping with recent assessments of hidden species diversity in birds. Our results clearly support the division of gentoo penguins into at least four species. We name a new species of gentoo, P. poncetii, and recommend elevation of three subspecies to species level (P. taeniata, P. papua, and P. ellsworthi). Our results show the importance of reassessing species boundaries as methodological advances are made. These findings have implications for the threat status of these species, and we urge that this diversity is considered in conservation planning for the Southern Ocean.

Joshua Tyler, Matthew T. Bonfitto, Gemma V. Clucas, Sushma Reddy and Jane L. Younger. 2020. Morphometric and Genetic Evidence for Four Species of Gentoo Penguin. Ecology and Evolution. DOI: 10.1002/ece3.6973  

 twitter.com/JoshTylerEarth/status/1324358369096966144

 twitter.com/Jane_Younger/status/1324356444255379459

 theconversation.com/how-we-discovered-three-new-species-of-penguin-in-the-southern-ocean-149325

[Paleontology • 2020] Antarcticoolithus bradyi • A Giant Soft-shelled Egg from the Late Cretaceous of Antarctica

Antarcticoolithus bradyi 

 Legendre, Rubilar-Rogers, Musser, et al., 2020

  DOI: 10.1038/s41586-020-2377-7

Illustration: Francisco Hueichaleo 

Abstract

Egg size and structure reflect important constraints on the reproductive and life-history characteristics of vertebrates. More than two-thirds of all extant amniotes lay eggs. During the Mesozoic era (around 250 million to 65 million years ago), body sizes reached extremes; nevertheless, the largest known egg belongs to the only recently extinct elephant bird, which was roughly 66 million years younger than the last nonavian dinosaurs and giant marine reptiles. Here we report a new type of egg discovered in nearshore marine deposits from the Late Cretaceous period (roughly 68 million years ago) of Antarctica. It exceeds all nonavian dinosaur eggs in volume and differs from them in structure. Although the elephant bird egg is slightly larger, its eggshell is roughly five times thicker and shows a substantial prismatic layer and complex pore structure. By contrast, the new fossil, visibly collapsed and folded, presents a thin eggshell with a layered structure that lacks a prismatic layer and distinct pores, and is similar to that of most extant lizards and snakes (Lepidosauria). The identity of the animal that laid the egg is unknown, but these preserved morphologies are consistent with the skeletal remains of mosasaurs (large marine lepidosaurs) found nearby. They are not consistent with described morphologies of dinosaur eggs of a similar size class. Phylogenetic analyses of traits for 259 lepidosaur species plus outgroups suggest that the egg belonged to an individual that was at least 7 metres long, hypothesized to be a giant marine reptile, all clades of which have previously been proposed to show live birth. Such a large egg with a relatively thin eggshell may reflect derived constraints associated with body shape, reproductive investment linked with gigantism, and lepidosaurian viviparity, in which a ‘vestigial’ egg is laid and hatches immediately.

A diagram showing the fossil egg Antarcticoolithus bradyi, its parts and size relative to an adult human.The giant egg has a soft shell. This is shown in dark gray in the drawing, with arrows pointing to its folds and surrounding sediment shown as light gray. 

Systematic palaeontology

Reptilia Laurenti, 1768 (sensu Modesto and Anderson, 2004)

Sauria Macartney, 1802 (sensu Rieppel and deBraga, 1996)

Oofamily, incertae sedis

Antarcticoolithus bradyi, oogen. and oospec. nov.

Etymology. Antarctic, referring to the continent where the specimen was discovered, Antarctica; oolithus, from Ancient Greek ōión for egg and líthos for stone; bradyi, from the Ancient Greek bradús for delayed or tardy, reflecting the 160 years between the description of the first Mesozoic egg from shallow marine deposits, Testudoflexoolithus bathonicae (Buckman, 1860), and that of this new ootaxon.

Holotype. SGO.PV 25.400, an almost complete fossil egg with infilled sediment (Fig. 1), permanently reposited at the Museo Nacional de Historia Natural, Santiago, Chile.

Locality and horizon. Late Cretaceous (roughly 68 Myr) of the López de Bertodano Formation (unit Klb; Supplementary Methods), Seymour Island, Antarctica.

Diagnosis. Antarcticoolithus bradyi is diagnosed by the following combination of characters: large size (29 cm × 20 cm, preserved length × width); eggshell thickness at least 700 μm and layered with a smooth undulating exterior surface; comparatively thin calcareous layer (roughly 100 μm); and complete lack of shell units and pores.

....

An artist’s interpretation of a mosasaur, an extinct marine reptile that scientists think may have laid the egg. An adult mosasaur is shown next to the egg and a hatchling.

Illustration: Francisco Hueichaleo

Lucas J. Legendre, David Rubilar-Rogers, Grace M. Musser, Sarah N. Davis, Rodrigo A. Otero, Alexander O. Vargas and Julia A. Clarke. 2020. A Giant Soft-shelled Egg from the Late Cretaceous of Antarctica. Nature.  DOI: 10.1038/s41586-020-2377-7

Egg from Antarctica is Big and Might Belong to an Extinct Sea Lizard

news.utexas.edu/2020/06/17/egg-from-antarctica-is-big-and-might-belong-to-an-extinct-sea-lizard 

facebook.com/MauricioAlvarez904108/posts/3005603219561318

uchile.cl/noticias/164365/descubren-en-antartica-el-huevo-mas-grande-de-era-de-los-dinosaurios

      

[Invertebrate • 2020] Anguillosyllis (Annelida: Syllidae) from Multiple Deep-water Locations in the Northern and Southern Hemispheres

Anguillosyllis acsara

 Maciolek, 2020  

 DOI:  10.11646/zootaxa.4793.1.1 

Abstract

Numerous specimens belonging to the syllid genus Anguillosyllis Day were collected during several deep-sea studies conducted between 1970 and 2011 in depths ranging from 180 to nearly 5000 m. These quantitative studies demonstrated that members of this genus are not as uncommon as once thought but can be among the 10 most common infaunal species at some deep-sea locations. Study areas included Georges Bank (New England), the North, Mid, and South Atlantic Continental Slope and Rise (east coast of North America), the Gulf of Mexico (off Louisiana), off San Francisco, California, the Clarion-Clipperton Fracture Zone (Pacific Ocean), the South China Sea (off Brunei), the abyssal plain in the South Atlantic Ocean, and Antarctica (Scotia Sea, Weddell Sea). Sixteen new species are described, bringing the total number of described Anguillosyllis species to 20; one additional species that cannot be fully characterized is also noted. The new species include eight with palps that are entirely or partially free (Anguillosyllis aciculata n. sp., A. acsara, n. sp., A. carolina n. sp., A. denaria n. sp., A. hadra, n. sp., A. hampsoni n. sp., A. taleola n. sp., and A. truebloodi n. sp.) and eight species with completely fused palps (A. andeepia n. sp., A. blakei n. sp., A. bruneiensis n. sp., A. elegantissima n. sp., A. enneapoda n. sp., A. hessleri n. sp., A. inornata n. sp., and A. sepula n. sp.). Type specimens of A. palpata (Hartman) from off Cape Horn and A. pupa (Hartman) from off New England were examined; A. capensis Day from South Africa and A. lanai Barroso, Paiva, Nogueira & Fukuda from Brazil are discussed. All adult Anguillosyllis have a fixed number of setigers, either 8, 9, 10, or 11, with 11 setigers being the most common. Species differ in the number of setigers, degree of fusion of the palps, degree of development of parapodial lobes, structure and number of internal and external glands, number of setae in anterior setigers, shape and size of proventricle, and annulation of the dorsum. All species for which the anal cirri had not been lost were found to have four, including two long, thin, ventromedial ones and two shorter, usually oval, lateral ones. Reproduction is poorly known in the genus; the present study shows eggs are found in the posterior (post-proventricle) setigers of most species and enter the parapodia from the coelom of several specimens; egg diameters generally ranged from 50–85 µm with A. sepula n. sp. having eggs up to 120 µm, the largest reported for the genus.

 Keywords: Annelida, ANDEEP, Antarctica, Atlantic Continental Slope and Rise, benthos, Borneo, Brunei, Clarion-Clipperton Fracture Zone, deep-sea, Georges Bank, New England, SF-DODS, South China Sea

Anguillosyllis acsara n. sp. Holotype (USNM 1480212)

Nancy J. Maciolek. 2020.  Anguillosyllis (Annelida: Syllidae) from Multiple Deep-water Locations in the Northern and Southern Hemispheres. Zootaxa. 4793(1); 1-73. DOI:  10.11646/zootaxa.4793.1.1