Endocranial Anatomy of Antarctic Eocene Stem Penguins: Implications for Sensory System Evolution in Sphenisciformes (Aves)

ABSTRACT Penguins have a more than 60 million year long evolutionary history. Thus, stem lineage fossil taxa are key to understanding their evolution. Here, we present data on three virtual endocasts from stem penguin skulls collected from the Eocene La Meseta Formation of Seymour Island (Antarctica), along with comparative data from extant penguins and outgroups. These fossils appear to belong to three distinct species, and represent both the oldest (34.2 Ma) and the most basal penguin taxa that have yielded endocast data. Data collected from the fossils provide new support for several important shifts in neuroanatomy and cranial skeletal anatomy along the transition from stem to crown penguins, including (1) caudal expansion of the eminentia sagittalis, (2) an increase in the overlap of the telencephalon onto the cerebellum, (3) reduction of the bulbus olfactorius, and (4) loss of the interaural pathway. The large semicircular canal diameters of the Antarctic fossils as well as the more crownward stem penguin Paraptenodytes antarcticus together suggest that canal size increased in basal penguins relative to outgroup taxa but later decreased near the crown radiation. As in most other wing-propelled diving birds, the endocasts lack evidence of cerebellar folds and possess a relatively large floccular recess. Several aspects of the endocast morphology, including the exposure of the tectum opticum in dorsal view and the rostral displacement of the eminentia sagittalis away from the border of the cerebellum, are seen neither in crown penguins nor in Procellariiformes (the extant sister clade to Sphenisciformes) and so appear to represent unique characters of these stem taxa.

• Publication year

  2015

• Venue

  Unknown venue

• Publication date

  2015-08-26

• Fields of study

  Biology, Environmental Science

• Identifiers
  DOI 10.1080/02724634.2015.981635
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar

• No claims are published for this paper.

• No concepts are published for this paper.

• Endocranial morphology of Pygoscelis calderensis (Aves, Spheniscidae) from the Neogene of Chile and remarks on brain morphology in modern Pygoscelis

  2015cited by this paper
• Unexpected microanatomical variation among Eocene Antarctic stem penguins (Aves: Sphenisciformes)

  2015cited by this paper
• Molecular evolution tracks macroevolutionary transitions in Cetacea.

  2014cited by this paper
• Enigmatic affinity in the brain morphology between plotopterids and penguins, with a comprehensive comparison among water birds

  2014influential reference
• Living Dinosaurs: The Evolutionary History of Modern Birds

  2014cited by this paper
• Avian Cerebellar Floccular Fossa Size Is Not a Proxy for Flying Ability in Birds

  2013cited by this paper
• Late Cretaceous/ Paleogene West Antarctica Terrestrial Biota and its Intercontinental Affinities.

  2013cited by this paper
• Taxonomic diversity of Eocene Antarctic penguins: a changing picture

  2013cited by this paper
• Evolutionary origins of the avian brain

  2013cited by this paper
• New crania from Seymour Island (Antarctica) shed light on anatomy of Eocene penguins

  2013cited by this paper
• Olfactory detection of dimethyl sulphide in a krill-eating Antarctic penguin

  2013cited by this paper
• The variability of inner ear orientation in saurischian dinosaurs: testing the use of semicircular canals as a reference system for comparative anatomy

  2013cited by this paper
• New Fossil Penguins (Aves, Sphenisciformes) from the Oligocene of New Zealand Reveal the Skeletal Plan of Stem Penguins

  2012cited by this paper
• Endocranial Anatomy of the Charadriiformes: Sensory System Variation and the Evolution of Wing-Propelled Diving

  2012influential reference
• Evolution of the brain and sensory organs in Sphenisciformes: new data from the stem penguin Paraptenodytes antarcticus

  2012cited by this paper
• Feeding habits of Antarctic Eocene penguins from a morphofunctional perspective

  2012cited by this paper
• Birds have paedomorphic dinosaur skulls

  2012cited by this paper
• Partial limb skeleton of a "giant penguin" Anthropornis from the Eocene of Antarctic Peninsula

  2012cited by this paper
• Halcyornis toliapicus (Aves: Lower Eocene, England) indicates advanced neuromorphology in Mesozoic Neornithes

  2011cited by this paper
• Evolution of olfaction in non-avian theropod dinosaurs and birds

  2011cited by this paper
• Penguins are attracted to dimethyl sulphide at sea

  2011cited by this paper
• Evolving Large and Complex Brains

  2011cited by this paper
• Collaborative electronic infrastructures to accelerate taxonomic research

  2011cited by this paper
• Taxonomic revision and phylogenetic analysis of the flightless Mancallinae (Aves, Pan-Alcidae)

  2011cited by this paper
• Aspects of Diversity in Early Antarctic Penguins

  2011cited by this paper
• Evolution of the Avian Brain and Senses

  2011cited by this paper
• Penguin cranial remains from the Eocene La Meseta Formation, Isla Marambio (Seymour Island), Antarctic Peninsula

  2011cited by this paper
• Fossil Evidence for Evolution of the Shape and Color of Penguin Feathers

  2010cited by this paper
• First articulated skeleton of Palaeeudyptes gunnari from the late Eocene of Isla Marambio (Seymour Island), Antarctica

  2010cited by this paper
• Semicircular canals and agility: the influence of size and shape measures

  2010cited by this paper
• The Basal Penguin (Aves: Sphenisciformes) Perudyptes devriesi and a Phylogenetic Evaluation of the Penguin Fossil Record

  2010cited by this paper
• Phylogenetic Analysis of Pelecaniformes (Aves) Based on Osteological Data: Implications for Waterbird Phylogeny and Fossil Calibration Studies

  2010influential reference
• Inner ear anatomy is a proxy for deducing auditory capability and behaviour in reptiles and birds

  2009influential reference
• New Insights Into the Brain, Braincase, and Ear Region of Tyrannosaurs (Dinosauria, Theropoda), with Implications for Sensory Organization and Behavior

  2009cited by this paper
• Olfactory acuity in theropods: palaeobiological and evolutionary implications

  2009cited by this paper
• CRC Handbook of Avian Body Masses. Second Edition

  2009cited by this paper
• Relative brain size and ecology in birds

  2009cited by this paper
• Avian brain evolution: new data from Palaeogene birds (Lower Eocene) from England

  2009influential reference
• Optic Foramen Morphology and Activity Pattern in Birds

  2009cited by this paper
• Fossil Counterparts of Giant Penguins from the North Pacific

  2008influential reference
• Comparative Anatomy and Physiology of Chemical Senses in Nonavian Aquatic Reptiles

  2008cited by this paper
• Comparative Anatomy and Physiology of Chemical Senses in Aquatic Birds

  2008cited by this paper
• African penguins (Spheniscus demersus) can detect dimethyl sulphide, a prey-related odour

  2008cited by this paper
• Sensory ecology on the high seas: the odor world of the procellariiform seabirds

  2008cited by this paper
• Osteology of Icadyptes salasi, a giant penguin from the Eocene of Peru

  2008cited by this paper
• A new Miocene penguin from Patagonia and its phylogenetic relationships

  2007cited by this paper
• The Semicircular Canals of Birds and Non-Avian Theropod Dinosaurs

  2007cited by this paper
• Evolution of Brain Size in the Palaeognath Lineage, with an Emphasis on New Zealand Ratites

  2007cited by this paper
• Paleogene equatorial penguins challenge the proposed relationship between biogeography, diversity, and Cenozoic climate change

  2007cited by this paper
• Phylogeny, histology and functional morphology of fossil penguins (Sphenisciformes)

  2007cited by this paper
• Structural Extremes in a Cretaceous Dinosaur

  2007cited by this paper
• The phylogeny of the living and fossil Sphenisciformes (penguins)

  2006cited by this paper
• The evolution of stereopsis and the Wulst in caprimulgiform birds: a comparative analysis

  2006cited by this paper
• Redescription and Phylogenetic Position of the Early Miocene Penguin Paraptenodytes Antarcticus from Patagonia

  2006cited by this paper
• Eocene penguins of Seymour Island, Antarctica: Taxonomy

  2006influential reference
• Patterns of the internal and cerebral carotid arteries in various avian species : a comparative study

  2006cited by this paper
• Pinguinos fosiles (Pygoscelis calderensis sp. nov.) en la Formacion Bahia Inglesa (Mioceno Medio-Plioceno), Chile

  2006cited by this paper
• Comparative Morphology of the Avian Cerebellum: I. Degree of Foliation

  2006cited by this paper
• Early penguin fossils, plus mitochondrial genomes, calibrate avian evolution.

  2006cited by this paper
• Eocene penguins of Seymour Island, Antarctica: The earliest record, taxonomic problems and some evolutionary considerations

  2006influential reference
• Avian skull morphological evolution: exploring exo- and endocranial covariation with two-block partial least squares.

  2006cited by this paper
• Late Eocene penguins from West Antarctica: systematics and biostratigraphy

  2006cited by this paper
• Fossil penguin (Aves: Sphenisciformes) cranial material from the Eocene of Seymour Island (Antarctica)

  2006cited by this paper
• Comparative Morphology of the Avian Cerebellum: II. Size of Folia

  2006cited by this paper
• A phylogeny of extant penguins (Aves: Sphenisciformes) combining morphology and mitochondrial sequences

  2005cited by this paper
• Evolution of the brain and intelligence.

  2005cited by this paper
• The Evolution of Cerebrotypes in Birds

  2005cited by this paper
• Audiogram, body mass, and basilar papilla length: correlations in birds and predictions for extinct archosaurs

  2005cited by this paper
• A comparative test of the correlated evolution of flightlessness and relative brain size in birds

  2004cited by this paper
• A mosaic pattern characterizes the evolution of the avian brain

  2004cited by this paper
• The avian nature of the brain and inner ear of Archaeopteryx

  2004cited by this paper
• Neuroanatomy of flying reptiles and implications for flight, posture and behaviour

  2003cited by this paper
• Los piqueros -aves: sulidae- de la formación Pisco, Perú

  2003cited by this paper
• Una nueva especie de spheniscidae del Mioceno Tardío de la Formación Pisco, Perú

  2003cited by this paper
• Una nueva especie de Spheniscus, aves: spheniscidae de la formación Pisco, Perú

  2002cited by this paper
• Can endocranial volume be used as an estimate of brain size in birds

  2002cited by this paper
• Taxonomic revision of Eocene Antarctic penguins based on tarsometatarsal morphology

  2002cited by this paper
• Vestibular evidence for the evolution of aquatic behaviour in early cetaceans

  2002cited by this paper
• Acoustic systems are adapted to breeding ecologies: individual recognition in nesting penguins

  2002cited by this paper
• FOREBRAIN ENLARGEMENT AMONG NONAVIAN THEROPOD DINOSAURS

  2000cited by this paper
• Olfactory foraging by Antarctic procellariiform seabirds: life at high Reynolds numbers.

  2000cited by this paper
• Acoustic communication in a king penguin colony: importance of bird location within the colony and of the body position of the listener

  1999cited by this paper
• Finding a parent in a king penguin colony: the acoustic system of individual recognition.

  1999cited by this paper
• STRATIGRAPHY OF THE LA MESETA FORMATION (EOCENE), MARAMBIO (SEYMOUR) ISLAND, ANTARCTICA

  1998cited by this paper
• Antarctic Peninsular cryosphere: Early Oligocene (c. 30 Ma) initiation and a revised glacial chronology

  1998influential reference
• Braincase of Enaliornis, an Early Cretaceous bird from England

  1991cited by this paper
• The craniofacial air sac system of Mesozoic birds (Aves)

  1990cited by this paper
• A new species of fossil penguin from Seymour Island, West Antarctica

  1990cited by this paper
• The Fossil Record of Birds

  1985cited by this paper
• Rete Mirabile Ophthalmicum in Hawaiian Seabirds

  1981cited by this paper
• Role of theRete mirabile ophthalmicum in maintaining the body-to-brain temperature difference in pigeons

  1979cited by this paper
• Relative Brain Size and Behavior in Archosaurian Reptiles

  1977cited by this paper
• An Interpretation of Skull Structure in Penguins

  1975cited by this paper
• Arterio-venous heat exchange systems in the Jackass penguin Spheniscus demersus

  1975cited by this paper
• Chapter 9 – Evolution of the Brain in Birds

  1973cited by this paper
• The avian brain

  1972cited by this paper
• Review of fossil penguins from Seymour Island

  1971cited by this paper
• Hearing in the blackfooted penguin, spheniscus demersus, as represented by the cochlear potentials.

  1969cited by this paper
• The Size of the Olfactory Bulb in 108 Species of Birds

  1968influential reference
• Brain Evolution and Archaeopteryx

  1968cited by this paper

• The hearing capabilities of the Dromornithidae (Aves), with inferences on acoustic communication and ecology

  2025cites this paper
• Insights into Argentavis magnificens (Aves, Teratornithidae) lifestyle based on neuroanatomy

  2024cites this paper
• Biological relevance and methodological implications of unexpected hearing thresholds in a diving bird

  2024cites this paper
• Paleoneurology of stem palaeognaths clarifies the plesiomorphic condition of the crown bird central nervous system

  2024cites this paper
• Brain surface morphology and ecological and macroevolutionary inferences of avian New World suboscines (Aves, Passeriformes, Tyrannides)

  2024cites this paper
• Children of time: the geological recency of intelligence and its implications for SETI

  2023cites this paper
• ANTECEDENTES HISTÓRICOS DE LA PALEOHERPETOLOGÍA ARGENTINA EN ANTÁRTIDA

  2022cites this paper
• Phaethontiformes and Aequornithes: The Aquatic and Semi-aquatic Neaovian Taxa

  2022cites this paper
• Micro‐CT guided illustration of the head anatomy of penguins (Aves: Sphenisciformes: Spheniscidae)

  2022cites this paper
• Paranasal sinus system and upper respiratory tract evolution in Mesozoic pelagic crocodylomorphs

  2021cites this paper
• The skull of the Miocene Spheniscus urbinai (Aves, Sphenisciformes): osteology, brain morphology, and the cranial pneumatic systems

  2021cites this paper
• New Remains of Scandiavis mikkelseni Inform Avian Phylogenetic Relationships and Brain Evolution

  2021cites this paper
• Endocranial morphology of the piciformes (Aves, Coraciimorphae): Functional and ecological implications

  2021cites this paper
• Wing Musculature Reconstruction in Extinct Flightless Auks (Pinguinus and Mancalla) Reveals Incomplete Convergence with Penguins (Spheniscidae) Due to Differing Ancestral States

  2020cites this paper
• The Role of Endocasts in the Study of Brain Evolution

  2020cites this paper
• Avian palaeoneurology: Reflections on the eve of its 200th anniversary

  2020cites this paper
• Beyond Endocasts: Using Predicted Brain-Structure Volumes of Extinct Birds to Assess Neuroanatomical and Behavioral Inferences

  2020cites this paper
• Endocast structures are reliable proxies for the sizes of corresponding regions of the brain in extant birds

  2020cites this paper
• Comparative osteology of the penguin‐like mid‐Cenozoic Plotopteridae and the earliest true fossil penguins, with comments on the origins of wing‐propelled diving

  2020cites this paper
• The fossil record of birds from the James Ross Basin, West Antarctica

  2019cites this paper
• A stem anseriform from the early Palaeocene of Antarctica provides new key evidence in the early evolution of waterfowl

  2019cites this paper
• The first skull of Anthropornis grandis (Aves, Sphenisciformes) associated with postcranial elements

  2019cites this paper
• The Evolution of Avian Intelligence and Sensory Capabilities: The Fossil Evidence

  2018cites this paper
• A re-evaluation of the basicranial soft tissues and pneumaticity of the therizinosaurian Nothronychus mckinleyi (Theropoda; Maniraptora)

  2018cites this paper
• Redescription of the Oldest Crown Clade Penguin: Cranial Osteology, Jaw Myology, Neuroanatomy, and Phylogenetic Affinities of Madrynornis Mirandus

  2018cites this paper
• Evolution of the Sauropterygian Labyrinth with Increasingly Pelagic Lifestyles.

  2017cites this paper
• On the Paleontology of Animal Cognition: Using the Brain Dimensions of Modern Birds to Characterize Maniraptor Cognition

  2017cites this paper
• Novel insights into early neuroanatomical evolution in penguins from the oldest described penguin brain endocast

  2016influential citation
• Braincase and Neuroanatomy of Pseudochampsa ischigualastensis and Tropidosuchus romeri (Archosauriformes, Proterochampsia)

  2016influential citation
• Penguins reduced olfactory receptor genes common to other waterbirds

  2016cites this paper
• Next-generation paleornithology: Technological and methodological advances allow new insights into the evolutionary and ecological histories of living birds

  2015cites this paper
• Neo y paleoornitología virtual

  2014cites this paper
• The first skull of Anthropornis grandis (Aves, Sphenisciformes) associated with postcranial elements

  year unknowncites this paper