Date of Award
Master of Science (MS)
College of Science and Mathematics
Thesis Sponsor/Dissertation Chair/Project Chair
Robert W. Meredith
Charadriiformes, Alcidae, Water birds, Cladistic analysis, Phylogeny
Pan-Alcidae is a clade of birds consisting of the crown-clade Alcidae and the extinct Mancallinae. They include 24 extant species, 1 recently extinct species, and a fossil record extending as far back as the Eocene. All extinct and extant Pan-alcid diversity exhibit an exclusively Holarctic distribution with the majority of extant diversity found in the Pacific. The relationships of the Pan-Alcidae have been a long-standing subject of debate. Early systematic hypotheses placed Pan-Alcidae as close relatives of various water birds, however modern phylogenetic hypotheses have supported their placement within Charadriiformes. Their exact placement within Charadriiformes has yielded multiple hypotheses with further difficulty found in resolving the relationships within the clade itself. Until recently, most work on Pan-Alcidae systematics focused primarily on extant diversity, neglecting to include data from their robust fossil record. By performing molecular, morphological, and combined analyses of Pan-Alcidae and a dense outgroup of Charadriiformes representatives, this study proposes hypotheses for the relationships of extinct and extant species. A novel hypothesis is proposed for the placement of the extinct Aethia rossmoori among the Brachyramphus. This relationship makes A. rossmoori the earliest known fossil from this lineage and extends the Brachyramphus lineage’s fossil record into the Late Miocene. Additionally, all analyses support the placement of Pseudocepphus teres as sister to the Cepphus extending their temporal and geographic range to include the Middle to Late Miocene Atlantic. A Bayesian total-evidence dating analysis estimated a divergence of Alcidae from other Charadriiformes during the Early Eocene. The divergence of the major Alcidae clades (the Fraterculinae and Alcinae) was estimated to have occurred during the Oligocene. Of 29 fossil Pan-Alcidae species, 6 were inferred to be sampled ancestors. Notably, Mancalla cedrosensis was inferred to be a direct ancestor of Mancalla californiensis providing a novel hypothesis for their previously supported close relationship.
DiGiacomo, Alexandria A., "A Phylogenetic Analysis of Extinct and Extant Pan-Alcidae (Charadriiformes: Aves)" (2018). Theses, Dissertations and Culminating Projects. 128.