A Total Evidence Cladistic Analysis of the Haliotidae (Gastropoda: Vetigastropoda).

Daniel L. Geiger

This total evidence cladistic analysis is partitioned into five chapters: nomenclature, fossils, coding strategies, biogeography, and combined data analysis.

All genus- and species-level taxa are reviewed. Fifty-six described species plus ten subspecies are considered valid. For all these taxa the geographic distribution and sources of published illustrations are given. All species are figured.

The taxonomy of the rare fossil abalone is problematic and their use in phylogenetics is questionable. Abalone first appear in the Maastrichian, are unknown in the Paleocene, reappear in the Eocene/Oligocene, and are regularly found from Miocene to Recent. A list of fossil records is given. Fossil and Recent abalone both lived in the shallow, rocky sublittoral in tropical and temperate climates. No on-shore/off-shore pattern was detected.

In cladistic analyses all observations are equivalent. A gap should be coded as a fifth character state. Global alignment of large sequences violates character independence, mandating the here-introduced minimal fragment alignment. Questionable alignments must be excluded or contracted; other methods conflict with the test of conjunction and/or contradict the original observation. Highly dissimilar sequences may be represented using the here-introduced block or stretch coding.

The distribution of all species is documented. The three models for the family's origin are evaluated. The area cladogram is in general agreement with an unrooted taxon cladogram. The basal node of the area cladogram is a fairly large polytomy uniting rather distant provinces such as the north Pacific, Australia, and Africa and is in closest agreement with the Indo-Pacific model for the origin. A major hiatus of approximately 200 million years can account for the discrepancy between the earliest fossils and the biogeographical reconstruction, as well as for the large basal polytomy in the biogeographical analysis.

The phylogenetic analysis reveals three consistent groupings: north Pacific, Australian endemics, and Indo-Pacific. Morphological data do not add information to the molecular hypotheses. Missing data is identified as a source for the numerous most parsimonious resolutions. Recommendations for the use of genus-level taxa are given.

A pdf version of the entire dissertation can be found at
<http://www.nhm.org/~dgeiger/dissertation.html>.