Comparative cranial morphology in living and extinct platypuses: Feeding behavior, electroreception, and loss of teeth

Asahara, Masakazu; Koizumi, Masahiro; Macrini, Thomas E.; Hand, Suzanne J.; Archer, Michael

doi:10.1126/sciadv.1601329

Cited by 17 publications

(10 citation statements)

References 22 publications

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“…In 1985, teeth and a nearly complete skull (Fig. 4A and 4B) of a species named Obdurodon dicksoni were discovered in Middle Miocene freshwater limestones (~15 Mya) in the Riversleigh World Heritage Area, Queensland (Lester and Archer 1986; Archer et al 1991, 1992, 1993, 2000; Musser and Archer 1998; Macrini et al 2006; Asahara et al 2016). A second, much larger, Riversleigh species, Obdurodon tharalkooschild , was later discovered (Pian et al 2013).…”

Section: Fossil Record and Phylogeographymentioning

confidence: 99%

The platypus: evolutionary history, biology, and an uncertain future

Bino

Kingsford

Archer

et al. 2019

Journal of Mammalogy

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The platypus ( Ornithorhynchus anatinus ) is one of the world’s most evolutionarily distinct mammals, one of five extant species of egg-laying mammals, and the only living species within the family Ornithorhynchidae. Modern platypuses are endemic to eastern mainland Australia, Tasmania, and adjacent King Island, with a small introduced population on Kangaroo Island, South Australia, and are widely distributed in permanent river systems from tropical to alpine environments. Accumulating knowledge and technological advancements have provided insights into many aspects of its evolutionary history and biology but have also raised concern about significant knowledge gaps surrounding distribution, population sizes, and trends. The platypus’ distribution coincides with many of Australia’s major threatening processes, including highly regulated and disrupted rivers, intensive habitat destruction, and fragmentation, and they were extensively hunted for their fur until the early 20th century. Emerging evidence of local population declines and extinctions identifies that ecological thresholds have been crossed in some populations and, if threats are not addressed, the species will continue to decline. In 2016, the IUCN Red Listing for the platypus was elevated to “Near Threatened,” but the platypus remains unlisted on threatened species schedules of any Australian state, apart from South Australia, or nationally. In this synthesis, we review the evolutionary history, genetics, biology, and ecology of this extraordinary mammal and highlight prevailing threats. We also outline future research directions and challenges that need to be met to help conserve the species.

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Section: Fossil Record and Phylogeographymentioning

confidence: 99%

The platypus: evolutionary history, biology, and an uncertain future

Bino

Kingsford

Archer

et al. 2019

Journal of Mammalogy

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“…Alternatively, absence of the TMJ disc in extant monotremes might be due to a secondary loss linked to the loss of teeth, and associated changes in the muscles of mastication. Extant adult monotremes are edentulous, possibly due to the expansion of the trigeminal during the evolution of electroreceptivity limiting the available space for tooth roots within the maxilla (Asahara et al, 2016). The juvenile platypus has rudimentary teeth that regress (Green, 1937), while the echidna shows only thickening of the dental epithelium during development.…”

Section: Introductionmentioning

confidence: 99%

The TMJ Disc Is a Common Ancestral Feature in All Mammals, as Evidenced by the Presence of a Rudimentary Disc During Monotreme Development

Anthwal

Tucker

2020

Front. Cell Dev. Biol.

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The novel mammalian jaw joint, known in humans as the temporomandibular joint or TMJ, is cushioned by a fibrocartilage disc. This disc is secondarily absent in therian mammals that have lost their dentition, such as giant anteaters and some baleen whales. The disc is also absent in all monotremes. However, it is not known if the absence in monotremes is secondary to the loss of dentition, or if it is an ancestral absence. We use museum held platypus and echidna histological sections to demonstrate that the developing monotreme jaw joint forms a disc primordium that fails to mature and become separated from the mandibular condyle. We then show that monotreme developmental anatomy is similar to that observed in transgenic mouse mutants with reduced cranial musculature. We therefore suggest that the absence of the disc on monotremes is a consequence of the changes in jaw musculature associated with the loss of adult teeth. Taken together, these data indicate that the ancestors of extant monotremes likely had a jaw joint disc, and that the disc evolved in the last common ancestor of all mammals.

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“…Alternatively, absence of the TMJ disc in extant monotremes might be due to a secondary loss of this structure, linked to changes in mastication with the reduction and loss of teeth. Extant adult monotremes are edentulous, possibly due to the evolution of electroreceptivity [20]. The juvenile platypus has rudimentary teeth that regress [21], while the echidna shows only thickening of the dental epithelium during development.…”

Section: Introductionmentioning

confidence: 99%

The TMJ disc is a common ancestral feature in all mammals, as evidenced by the presence of a rudimentary disc during monotreme development

Anthwal

Tucker

2020

Preprint

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The novel mammalian jaw joint, known in humans as the temporomandibular joint or TMJ, is cushioned by a fibrocartilage disc. This disc is secondarily absent in therian mammals that have lost their dentition, such as giant anteaters and some baleen whales. The disc is also absent in all monotremes. However, it is not known if the absence in monotremes is secondary to the loss of dentition, or if it is an ancestral absence. We use museum held platypus and echidna histological sections to demonstrate that the developing monotreme jaw joint forms a disc primordium that fails to mature and become separated from the mandibular condyle. We then show that monotreme developmental anatomy is similar to that observed in transgenic mouse mutants with reduced musculature. We therefore suggest that the absence of the disc on monotremes is a consequence of the changes in jaw musculature associated with the loss of adult teeth. Taken together, these data indicate that the ancestors of extant monotremes likely had a jaw joint disc, and that the disc evolved in the last common ancestor or all mammals.

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Comparative cranial morphology in living and extinct platypuses: Feeding behavior, electroreception, and loss of teeth

Abstract: Comparative morphology in living and extinct platypuses revealed that there was a shift in feeding behavior and sensory efficiency.

Cited by 17 publications

References 22 publications

The platypus: evolutionary history, biology, and an uncertain future

The platypus: evolutionary history, biology, and an uncertain future

The TMJ Disc Is a Common Ancestral Feature in All Mammals, as Evidenced by the Presence of a Rudimentary Disc During Monotreme Development

The TMJ disc is a common ancestral feature in all mammals, as evidenced by the presence of a rudimentary disc during monotreme development

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