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The comparative morphology and phylogeny of the Monacanthid fishes

Hutchins, J B (1988) The comparative morphology and phylogeny of the Monacanthid fishes. PhD thesis, Murdoch University.

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The family Monacanthidae was investigated firstly, to determine the number of valid species and their correct nomenclature, and secondly, to discover the relationships within the family as evidenced by its comparative morphology, in particular its osteology.

A total of 97 species of monacanthid fishes are considered valid, the list of nominal species numbering 255 (a brief taxonomic resume is provided). The morphology of each species is described, concentrating on those characters considered to have potential as indicators of evolutionary change [these were selected on the basis of three previous studies (Fraser-Brunner, 1941; Matsuura 1979; and Tyler, 1980), in addition to many new features reported here for the first time]. Numerous illustrations of the distinguishing features are included.

An analysis of the phylogenetic relationships is presented, following the cladistic approach of Hennig. At the generic level, 30 assemblages in three distinct lineages are recognised, a finding based on the derived states of the following characters: first dorsal, second dorsal, anal, and caudal fins, basal pterygiophores of the first and second dorsal fins, cranium, vertebral column, pelvis and associated structures, scalation, lateral line sensory system teeth, branchiostegals, and sexual dimorphism. However, the monophyly of each of these assemblages is not proven in all cases. Furthermore the relationships of the genera in each of the first two lineages are only partly resolved, whereas those of the third are fully resolved. Three species could not be placed in any of the known genera and each has been treated as representing an undescribed monotypic genus. The intrageneric relationships proved difficult to resolve in numerous instances due to the lack of identifiable synapomorphies.

A discussion is presented on the above relationships and includes a comparison with previous hypothesised phylogenies.

Item Type: Thesis (PhD)
Murdoch Affiliation: School of Biological and Environmental Sciences
Notes: Note to the author: If you would like to make your thesis openly available on Murdoch University Library's Research Repository, please contact: Thank you.
Supervisor(s): Lethbridge, Roger
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