Redescription of the oldest crown clade penguin: cranial osteology, jaw myology, neuroanatomy, and phylogenetic affinities of <i>Madrynornis mirandus</i>

Degrange, Federico J.; Ksepka, Daniel T.; Tambussi, Claudia Patricia

doi:10.1080/02724634.2018.1445636

Cited by 20 publications

(41 citation statements)

References 55 publications

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“…Re-study of the holotype has revealed new character evidence and the most recent phylogenetic analysis suggested that Madrynornis is instead more closely related to Spheniscus and Eudyptula, though support was weak for this hypothesis (trees placing the fossil with Eudyptes were only one step longer). Nevertheless, seven synapomorphies support crown status for Madrynornis, most compellingly the widely separated fossa temporalis, elongate processus retroarticularis, and small foramen ilioischiadicum [191]. Given the strong evidence that Madrynornis is a crown penguin and the lingering uncertainty over the precise placement of this taxon, we use Madrynornis as a calibration for the penguin crown group.…”

Section: A9 Calibrated Node: Stem Phaethontiformesmentioning

confidence: 99%

A Phylogenomic Supertree of Birds

et al. 2019

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It has long been appreciated that analyses of genomic data (e.g., whole genome sequencing or sequence capture) have the potential to reveal the tree of life, but it remains challenging to move from sequence data to a clear understanding of evolutionary history, in part due to the computational challenges of phylogenetic estimation using genome-scale data. Supertree methods solve that challenge because they facilitate a divide-and-conquer approach for large-scale phylogeny inference by integrating smaller subtrees in a computationally efficient manner. Here, we combined information from sequence capture and whole-genome phylogenies using supertree methods. However, the available phylogenomic trees had limited overlap so we used taxon-rich (but not phylogenomic) megaphylogenies to weave them together. This allowed us to construct a phylogenomic supertree, with support values, that included 707 bird species (~7% of avian species diversity). We estimated branch lengths using mitochondrial sequence data and we used these branch lengths to estimate divergence times. Our time-calibrated supertree supports radiation of all three major avian clades (Palaeognathae, Galloanseres, and Neoaves) near the Cretaceous-Paleogene (K-Pg) boundary. The approach we used will permit the continued addition of taxa to this supertree as new phylogenomic data are published, and it could be applied to other taxa as well.

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Section: A9 Calibrated Node: Stem Phaethontiformesmentioning

confidence: 99%

A Phylogenomic Supertree of Birds

et al. 2019

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“…The most recent phylogenetic analysis using new characters from the holotype suggests that Madrynornis is more closely related to Spheniscus and Eudyptula, though this was weakly supported (trees placing the fossil with Eudyptes were only one step longer). Nevertheless, seven synapomorphies support crown status for Madrynornis, most compellingly the widely separated fossa temporalis, elongate processus retroarticularis, and small foramen ilioischiadicum (Degrange et al 2018). Given the strong evidence that Madrynornis is a crown penguin but uncertainty over the precise relationships of this taxon, we use Madrynornis to calibrate the penguin crown; Minimum Age Constraint: 9.7 Ma; Maximum Age Constraint: 25.2 Ma; Prior Distribution: uniform; Justification: The single specimen of M. mirandus was collected from the ''Entrerriense'' sequence of the Puerto Madryn Formation (Acosta Hospitaleche et al 2007); deposited at 10.0 ± 0.3 Ma (Scasso et al 2001).…”

Section: Fossil Calibrationsmentioning

confidence: 99%

Mitogenomes Uncover Extinct Penguin Taxa and Reveal Island Formation as a Key Driver of Speciation

Cole

Ksepka

Tennyson

et al. 2019

Molecular Biology and Evolution

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The emergence of islands has been linked to spectacular radiations of diverse organisms. Although penguins spend much of their lives at sea, they rely on land for nesting, and a high proportion of extant species are endemic to geologically young islands. Islands may thus have been crucial to the evolutionary diversification of penguins. We test this hypothesis using a fossil-calibrated phylogeny of mitochondrial genomes (mitogenomes) from all extant and recently extinct penguin taxa. Our temporal analysis demonstrates that numerous recent island-endemic penguin taxa diverged following the formation of their islands during the Plio-Pleistocene, including the Galápagos (Galápagos Islands), northern rockhopper (Gough Island), erect-crested (Antipodes Islands), Snares crested (Snares) and royal (Macquarie Island) penguins. Our analysis also reveals two new recently extinct island-endemic penguin taxa from New Zealand’s Chatham Islands: Eudyptes warhami sp. nov. and a dwarf subspecies of the yellow-eyed penguin, Megadyptes antipodes richdalei ssp. nov. Eudyptes warhami diverged from the Antipodes Islands erect-crested penguin between 1.1 and 2.5 Ma, shortly after the emergence of the Chatham Islands (∼3 Ma). This new finding of recently evolved taxa on this young archipelago provides further evidence that the radiation of penguins over the last 5 Ma has been linked to island emergence. Mitogenomic analyses of all penguin species, and the discovery of two new extinct penguin taxa, highlight the importance of island formation in the diversification of penguins, as well as the extent to which anthropogenic extinctions have affected island-endemic taxa across the Southern Hemisphere’s isolated archipelagos.

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“…This holds largely true even for great auks, which became extinct in the 19th Century before much was learned about their anatomy (Lucas 1890;Fuller 1999). Despite much work on various morphological aspects of these extinct wing-propelled divers, including morphometrics (Livezey 1988(Livezey , 1989, limb bone histology (Smith and Clarke 2014;Ksepka et al 2015), feeding morphology Acosta Hospitaleche 2012, 2014;Degrange et al 2018;Chávez-Hoffmeister 2020), and neuroanatomy (Ksepka et al 2012b;Smith and Clarke 2012;Kawabe et al 2014;Tambussi et al 2015;Proffitt et al 2016), surprisingly little is known about the musculoskeletal anatomy of the wings in extinct wing-propelled diving birds, perhaps with the exception of specific aspects of the musculature in stem penguins (Acosta Hospitaleche and Di Carlo 2012; Haidr and Acosta Hospitaleche 2019).…”

Section: Introductionmentioning

confidence: 99%

Wing musculature reconstruction in extinct flightless auks (PinguinusandMancalla) reveals incomplete convergence with penguins (Spheniscidae) due to differing ancestral states

Watanabe

Field

Matsuoka

2020

Preprint

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Despite longstanding interest in convergent evolution, factors that result in deviations from fully convergent phenotypes remain poorly understood. In birds, the evolution of flightless wing-propelled diving has emerged as a classic example of convergence, having arisen in disparate lineages including penguins (Sphenisciformes) and auks (Pan-Alcidae, Charadriiformes). Nevertheless, little is known about the functional anatomy of the wings of flightless auks because all such taxa are extinct, and their morphology is almost exclusively represented by skeletal remains. Here, in order to re-evaluate the extent of evolutionary convergence among flightless wing-propelled divers, wing muscles and ligaments were reconstructed in two extinct flightless auks, representing independent transitions to flightlessness: Pinguinus impennis (a crown-group alcid), and Mancalla (a stem-group alcid). Extensive anatomical data were gathered from dissections of 12 species of extant charadriiforms and 4 aequornithine waterbirds including a penguin. It was found that the wings of both flightless auk taxa were characterized by an increased mechanical advantage of wing elevator/retractor muscles, and decreased mobility of distal wing joints, both of which are likely advantageous for wing-propelled diving and parallel similar functional specializations in penguins. However, the conformations of individual muscles and ligaments underlying these specializations differ markedly between penguins and flightless auks, instead resembling those in each respective group’s close relatives. Thus, the wings of these flightless wing-propelled divers can be described as convergent as overall functional units, but are incompletely convergent at lower levels of anatomical organization—a result of retaining differing conditions from each group’s respective volant ancestors. Detailed investigations such as this one may indicate that, even in the face of similar functional demands, courses of phenotypic evolution are dictated to an important degree by ancestral starting points.

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Redescription of the oldest crown clade penguin: cranial osteology, jaw myology, neuroanatomy, and phylogenetic affinities of Madrynornis mirandus

Cited by 20 publications

References 55 publications

A Phylogenomic Supertree of Birds

A Phylogenomic Supertree of Birds

Mitogenomes Uncover Extinct Penguin Taxa and Reveal Island Formation as a Key Driver of Speciation

Wing musculature reconstruction in extinct flightless auks (PinguinusandMancalla) reveals incomplete convergence with penguins (Spheniscidae) due to differing ancestral states

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