Thesis
Comparative Jaw Muscle Anatomy of the Numbat (Myrmecobius fasciatus) and Carnivorous Marsupials (Dasyurus Species)
Honours, Murdoch University
2023
Abstract
Mastication plays a fundamental role in the feeding strategies of most mammals with variation in skull and jaw muscle anatomy closely associated with dietary preferences. As food items have different mechanical properties, mammals exhibit anatomical adaptations in the masticatory apparatus (e.g., dentition, jaw muscle proportions) to facilitate the processing of different diets. As species evolve to a more restricted diet (i.e., particular food items), anatomical adaptations become more specialised. We investigated the jaw muscle anatomy of the numbat (Myrmecobius fasciatus), the only obligate myrmecophagous (ant or termite eating) marsupial, in comparison to their carnivorous relatives (quolls), utilising both gross dissection and contrast enhanced μCT imaging techniques.
This study provides the first comprehensive qualitative and quantitative descriptions of jaw muscle anatomy in numbats and four species of quoll (Dasyurus geoffroii, D. hallucatus, D. maculatus, D. viverrinus), ranging in body size (558 g – 1443 g average species mass) and diets from mixed-animalivory (arthropods and small vertebrates) to carnivory. Numbats had an overall reduced temporalis muscle and modified digastric muscle in comparison to quolls, reflecting their specialised myrmecophagous diet. Quantitative analyses found numbats displayed differences in mechanical advantage not strictly linked to body size, while among the quolls, jaw muscle anatomy and size were strongly linked to body size. Insights gained from this study can contribute to broader ecological and evolutionary inquiries of the relationship between jaw muscle anatomy, skull morphology and diet in mammals.
Details
- Title
- Comparative Jaw Muscle Anatomy of the Numbat (Myrmecobius fasciatus) and Carnivorous Marsupials (Dasyurus Species)
- Authors/Creators
- Vanessa J Thomas
- Contributors
- Natalie Warburton (Supervisor) - Murdoch University, Centre for Terrestrial Ecosystem Science and SustainabilityJeremy Shaw (Supervisor) - The University of Western Australia
- Awarding Institution
- Murdoch University; Honours
- Identifiers
- 991005625167307891
- Murdoch Affiliation
- Murdoch University
- Resource Type
- Thesis
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