Systematics of a new fossil penguin (Spheniscidae) from the Kokoamu Greensand (Duntroonian stage, upper Oligocene), South Island, New Zealand

Jones, Craig M.

A new genus and new species of large fossil penguin is described, based on three well preserved substantially complete articulated skeletons. Elements or complexes represented are the rostrum; parts of the cranium including quadrate, mandible, many vertebrae and the pygostyle, many ribs, sternum, coracoid, scapula, all of the forelimb, pelvis, femur, tibia, tarsus, and most of the digits. Six previously described supposedly indeterminate specimens are referred to the new taxon. All . specimens are from the Kokoamu Greensand (upper Whaingaroan to Duntroonian · Stage, Upper Oligocene) of the Duntroon and Waihao districts, South Island, New Zealand. The newly described material usefully links many elements known previously from isolated bones. The partial skeletons thus provide much phylogenetic and functional information hitherto unavailable through the study of single bones. This information helps elucidate broader evolutionary relationships amongst fossil penguins. In this study, potentially useful taxonomic characters were identified using both literature and comparisons between the new fossil species and other described fossil and modern taxa. The states for these characters were determined for twenty nine modern, fossil and outgroup taxa including a possible ancestral fossil penguin (OU 12651). Cladograms were generated using the program PAUP version 3.1 (Phylogenetic Analysis Using Parsimony). The resulting consensus tree reinforced the monophyly of penguins. Within the penguin clade, six discrete groups were identified, each formed by either multi~axa, monophyletic clades or clusters of monospecific paraphyletic stem groups. Each group was separated by many state changes; of note, there is a major structural gap between Eocene/Oligocene penguins (including the new species), and later Neogene to Recent taxa. The new species was positioned in the middle of the stem group. Analyses of functional morphology and scaling in th~ new fossil species identified a range of skull pectoral girdle, forelimb and hindlimb features that differed from modem species. A body mass estimate of 60 kg is based on forelimb surface area. The stratigraphic distribution of fossil species and the disappearance of large fossil penguins is discussed in light of the results of the phylogenetic and functional analysis.

vii, 188 leaves, 35 leaves of plates : ill. (some col.), maps ; 30 cm.

1995Jones_CM