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Systematics of Favonigobius Whitley, 1930 with a description of aspects of the ecology of Favonigobius lateralis and other goby species in the Swan Estuary

Gill, Howard Stamper (1992) Systematics of Favonigobius Whitley, 1930 with a description of aspects of the ecology of Favonigobius lateralis and other goby species in the Swan Estuary. PhD thesis, Murdoch University.

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Abstract

A total of 26,232 gobies, representing seven species, was collected between September 1984 and March 1986, from 15 sites located throughout the Swan Estuary in south-western Australia. Favonigobius lateralis and Pseudogobius olorum contributed 47.0 and 47.8% respectively to the total catch of gobies. The relative contributions of each species at each site in the entrance channel (lower estuary), the large basins (middle estuary) and saline reaches of the tributary rivers (upper estuary) were determined. Comparisons of these data with those on the distribution and abundance of larvae confirmed that Favonigobius lateralis is a marine species that spawns near the estuary mouth or in inshore coastal waters. In contrast, Pseudogobius olorum, Afurcagobius (previously Favonigobius) suppositus, Papillogobius punctatus and Amoya bifrenatus complete their life cycles in the upper estuary. Tridentiger trigonocephalus is an introduced and marine species that was found only in the lower estuary. A single individual of the marine species Callogobius depressus was caught. The relatively low numbers of gobies in the middle estuary, where they contributed only ca 3.5% to the total numbers in the system, may represent an aversion to the high level of water disturbance that occurs in the large basins.

A new genus, Papillogobius, is described from specimens collected in the Swan Estuary and the genus Favonigobius Whitley, 1930 is redescribed. The type species of the new genus, Papillogobius punctatus, had previously been identified as Favonigobius lateralis (M'ddzay, 1881). These species are described and redescribed, respectively. On the basis of several shared osteological and morphological characters, Favonigobius exquisitus, Favonigobius melanobranchus and Favonigobius reichei are placed in the new genus.

Although many of the characters typically used in fish taxonomy have become reduced or lost in the gobioid fishes, the papillae of the cephalic lateral-line system have been highly modified. The validity of using the papillae patterns as a taxonomic tool has been explored by comparing data for this and other character suites recorded for the species assigned to Favonigobius and Papillogobius and also to Glossogobius giuris. The papillae patterns and major osteological and morphological characters of the above species are described and subjected to phenetic analyses. The classifications generated by this approach are compared wiith classifications produced by descriptive taxonomy and by multivariate analyses of morphometric data. All three approaches yielded the same groupings and intra-group relationships. The results suggest that those species which were previously called Favonigobius suppositus and Favonigobius tamarensis do not belong in Favonigobius.

A detailed comparison of the osteology of Favonigobius suppositus and Favonigobius tamarensis are described and compared with those of Favonigobius lateralis, Papillogobius spp. and Glossogobius spp.. These comparisons support the removal of Favonigobius suppositus and Favonigobius tamarensis from Favonigobius. A new genus, Afurcagobius, is proposed for Favonigobius suppositus, the type species, and for Favonigobius tamarensis. A key is provided to these two species and the other Australian genera and species with which they have been most recently associated.

The question of the monophyly and the intergeneric relationships of Favonigobius, Papillogobius, Afurcagobius, Glossogobius and the other gobiid genera with which they are phenetically associated, is explored. This study supports the hypothesis that these genera form a monophyletic group. It also indicates that the genera with 26 and 27 vertebrae are sister groups and that the group bearing 26 vertebrae contains two sister groups. Synapomorphies for these groups are proposed and the evolutionary development of the papillae patterns is postulated.

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: repository@murdoch.edu.au. Thank you.
Supervisor(s): Potter, Ian and Bradley, Stuart
URI: http://researchrepository.murdoch.edu.au/id/eprint/52067
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