Author

Kwan Wah Li

Year

2015

Degree Name

BEnviSci Hons

ANZSRC / FoR Code

060302 Biogeography and Phylogeography, 060205 Marine and Estuarine Ecology (incl. Marine Ichthyology)

Department

School of Earth & Environmental Sciences

Advisor(s)

David Ayre

Abstract

Sound taxonomy is the basis for all biological research and fisheries management. However, in some animal groups there are taxonomic uncertainties. This is especially true in the case of non-commercially targeted pelagic marine organisms, which are sometimes poorly known due to the serendipitous nature of their collection and sometimes a lack of well-preserved material. Knowledge of some groups is also limited due to a general lack of taxonomic expertise.

Representatives of one cephalopod genus, Abraliopsis Joubin, 1896, have been recorded from Australian waters; however, there was not much information available regarding the distribution and morphology of representatives of this group prior to the present study. Four species of Abraliopsis have been recorded: A. affinis (Pfeffer, 1912), A. gilchristi (Robson, 1924), A. hoylei (Pfeffer, 1884) and A. tui Riddell, 1985. This work re-examines the morphology and distributions of the Abraliopsis specimens held in two large museum collections (the Australian Museum and Museum Victoria) to assign unidentified specimens to species and determine whether the previous species identifications are correct. Three species were identified: A. gilchristi, A. lineata (Goodrich, 1896) and A. tui. Four female specimens of an unknown species from off the coast of the Queensland (about 254 km offshore) were found among collections. The discovery of A. lineata among specimens from off northeastern Queensland is the first record of this species from Australian waters. This species is fully described in this thesis as a basis for comparison with other specimens elsewhere over its broad geographical range.

At present it is impossible to assign specimens to Abraliopsis hoylei due to the lack of information and loss of the holotype. Until specimens of this species from the type locality in the Western Indian Ocean are examined, and the species redescribed it is not possible to resolve the identity of this species. Based on some very scant descriptions and material available to us it appears that this species may not actually occur in Australian waters, contrary to earlier reports.

This survey of the existing Australian Abraliopsis specimens has enhanced our knowledge of the composition and distribution of species within Australian waters and provides a clearer framework for management and study of these species and some directions for future research.

Prior to this study A. lineata had been recorded from the northern Indian Ocean and elsewhere in the tropical west Pacific. Together with the new north Queensland records the distributions of this taxon is quite disjunct as no specimens have been recorded from in between these three areas. This suggests the need for a more careful study of A. lineata’s distribution and morphological and genetic characters over the full range of the supposed species in case the existing populations may represent more than one, possibly cryptic, species. At this time it is not known whether the apparently disjunct distributions are simply a sampling artefact.

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