A new small-sized penguin from the late Eocene of Seymour Island with additional material of <i>Mesetaornis polaris</i>

Jadwiszczak, Piotr; Reguero, Marcelo Alfredo; Mörs, Thomas

doi:10.1080/11035897.2021.1900385

Cited by 7 publications

(4 citation statements)

References 17 publications

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“…2017). NRM‐PZ A632 and NRM‐PZ A1005 have been collected by Thomas Mörs in February 2011 and January 2012 from the richly fossiliferous site NRM 2 (64°14.778′S, 56°37.169′W; Jadwiszczak & Mörs 2016, 2021), situated in the steep slope southeast of the Marambio Base, above the before‐mentioned plateau. Nevertheless, all sites expose the middle part of the Submeseta Formation (Submeseta II = level 38; Montes et al.…”

Section: Methodsmentioning

confidence: 99%

“…2019; Jadwiszczak et al. 2021). The vast majority of specimens is represented by single, isolated, and incomplete bones; synsacra are very rare.…”

Section: Introductionmentioning

confidence: 99%

“…The assemblage of early Sphenisciformes from Seymour Island comprises a single Paleocene (66.0-56.0 Ma) and at least 11 Eocene species (e.g. Acosta Hospitaleche et al 2019;Jadwiszczak et al 2021). The vast majority of specimens is represented by single, isolated, and incomplete bones; synsacra are very rare.…”

Section: Introductionmentioning

confidence: 99%

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An integrative insight into the synsacral canal of fossil and extant Antarctic penguins

2022

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The lumbosacral-canal system in birds most likely operates as a sense organ involved in the control of balanced walking and perching, but our knowledge of it is superficial. Penguins constitute interesting objects for the study of this system due to their upright walking, but only the Humboldt penguin, Spheniscus humboldti, and some incomplete fossil penguin synsacra have been studied in this respect. Here, we give an integrative comparative insight into the synsacral canal of extant Emperor penguin, Aptenodytes forsteri, Adelie penguin, Pygoscelis adeliae, and Eocene giant Anthropornis and/or Palaeeudyptes Antarctic penguins, using computed tomography imaging and associated data-extraction methodologies, complemented by analytical approaches ranging from geometric morphometrics to modularity, curvature, and wavelet analyses. We document that the variability in the number of synsacro-lumbar vertebrae is evolutionarily conserved, and all studied synsacra possess osteological correlates of the lumbosacral-canal system. We also found that Eocene and extant Antarctic penguins were separable on the basis of the main direction of the shape-related (size-independent) variability within said system, and A. forsteri was unique in the entire studied set in terms of the relative cranial shift of this compound structure. Moreover, we suggest that the evolutionary processes, shaping both the terrestrial posture and gait, were responsible, in extant penguins, for the increased simplicity and stability of the synsacral canal cross-sectional periodic patterns, as well as pave the way for the lumbosacral-canal system modularity characterized by reduced atomization/complexity.

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Section: Methodsmentioning

confidence: 99%

“…2019; Jadwiszczak et al. 2021). The vast majority of specimens is represented by single, isolated, and incomplete bones; synsacra are very rare.…”

Section: Introductionmentioning

confidence: 99%

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An integrative insight into the synsacral canal of fossil and extant Antarctic penguins

2022

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“…Even though the list of penguin fossil species is much more extensive, rigorous analyses carried out over recent decades have established long synonymic lists of species and genera that are no longer considered valid. Table 1 follows the taxonomic arrangements proposed for Argentinian [63][64][65][66][67][68][69][70][71], Chilean [67,69,72,73,78,81], Peruvian [24,28,41,57,69,73], Antarctic [27,[49][50][51][52][53][54][57][58][59], New Zealand [11,17,19,20,33,38,42,48,55,60], Australian [56,67,75], and African [76,77] taxa. This compilation is essential to obtain complementary information for the discussion and the palaeoecological analysis.…”

Section: Species Considered In the Present Analysismentioning

confidence: 99%

Evolutionary and Biogeographical History of Penguins (Sphenisciformes): Review of the Dispersal Patterns and Adaptations in a Geologic and Paleoecological Context

Pelegrin

Hospitaleche

2022

Diversity

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Despite its current low diversity, the penguin clade (Sphenisciformes) is one of the groups of birds with the most complete fossil record. Likewise, from the evolutionary point of view, it is an interesting group given the adaptations developed for marine life and the extreme climatic occupation capacity that some species have shown. In the present contribution, we reviewed and integrated all of the geographical and phylogenetic information available, together with an exhaustive and updated review of the fossil record, to establish and propose a biogeographic scenario that allows the spatial-temporal reconstruction of the evolutionary history of the Sphenisciformes, discussing our results and those obtained by other authors. This allowed us to understand how some abiotic processes are responsible for the patterns of diversity evidenced both in modern and past lineages. Thus, using the BioGeoBEARS methodology for biogeographic estimation, we were able to reconstruct the biogeographical patterns for the entire group based on the most complete Bayesian phylogeny of the total evidence. As a result, a New Zealand origin for the Sphenisciformes during the late Cretaceous and early Paleocene is indicated, with subsequent dispersal and expansion across Antarctica and southern South America. During the Eocene, there was a remarkable diversification of species and ecological niches in Antarctica, probably associated with the more temperate climatic conditions in the Southern Hemisphere. A wide morphological variability might have developed at the beginning of the Paleogene diversification. During the Oligocene, with the trends towards the freezing of Antarctica and the generalized cooling of the Neogene, there was a turnover that led to the survival (in New Zealand) of the ancestors of the crown Sphenisciform lineages. Later these expanded and diversified across the Southern Hemisphere, strongly linked to the climatic and oceanographic processes of the Miocene. Finally, it should be noted that the Antarctic recolonization and its hostile climatic conditions occurred in some modern lineages during the Pleistocene, possibly due to exaptations that made possible the repeated dispersion through cold waters during the Cenozoic, also allowing the necessary adaptations to live in the tundra during the glaciations.

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Phaethontiformes and Aequornithes: The Aquatic and Semi-aquatic Neaovian Taxa

Mayr

2022

Paleogene Fossil Birds

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A new small-sized penguin from the late Eocene of Seymour Island with additional material of Mesetaornis polaris

Cited by 7 publications

References 17 publications

An integrative insight into the synsacral canal of fossil and extant Antarctic penguins

An integrative insight into the synsacral canal of fossil and extant Antarctic penguins

Evolutionary and Biogeographical History of Penguins (Sphenisciformes): Review of the Dispersal Patterns and Adaptations in a Geologic and Paleoecological Context

Phaethontiformes and Aequornithes: The Aquatic and Semi-aquatic Neaovian Taxa

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