Ph.D. Thesis

Avian Louse Phylogeny (Phthiraptera: Ischnocera): A cladistic study based on morphology

VINCENT S. SMITH

Division of Environmental and Evolutionary Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom.

Corresponding Author: Vince Smith
e-mail: v.smith@bio.gla.ac.uk

Status: Awarded May, 2000

Abstract

The systematics and taxonomy of avian chewing lice from the suborder Ischnocera (Phthiraptera) is investigated. Comparative anatomy based on adult and instar morphology is used to explore both classical and novel homology hypotheses for a variety of character systems, including chaetotaxy, head shape, preantennal morphology and internal genitalia. These are critically examined within a phylogenetic context. The role of ontogeny in the development of the major character complexes of the head and abdomen is considered, and its implications for further work on the systematics of avian Ischnocera is discussed. Elliptic Fourier analysis is used to explore the evolution of louse head shape. Rates of heterochrony and the performance of alternative character state transformation series are evaluated. These data are used to build the first cladistic hypotheses for avian chewing lice (suborder Ischnocera). Generic and familial relationships are investigated for a diverse selection of ischnoceran taxa spanning 13 bird orders (32 bird families), with particular emphasis on the ischnoceran chewing lice of galliform, columbiform and tinamiform birds (families Goniodidae and Heptapsogasteridae). Comparison with host taxonomy reveals a series of complex host parasite associations which do not support a hypothesis of one to one cospeciation. However, interpretation of these comparisons is hampered by the fact that less than one thirtieth of the 2,700 species of avian ischnoceran lice were examined. Future prospects for understanding more about the coevolutionary relationships between lice and their hosts are considered.

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Smith, V. S. (2000) Avian Louse Phylogeny (Phthiraptera: Ischnocera): A cladistic study based on morphology. Unpublished Ph.D. thesis.

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