An Alphataxonomic Revision of Extinct and Extant Razorbills (Aves, Alcidae): A Combined Morphometric and Phylogenetic Approach

Sixteen vetted fossil calibrations for divergence dating of Charadriiformes (Aves, Neognathae)

“…Therefore, this calibration must be based solely on the holotype specimen until associated remains of this taxon are discovered that would allow for referral of additional skeletal elements or until the stratigraphic range of Synthliboramphus rineyi is extended by recovery of additional remains referable to that taxon. (Smith, 2011a;Smith and Clarke, 2011). The sister taxon relationship between Uria and Alle is also supported by the results of previous analyses of molecular sequence data (Thomas et al, 2004;Pereira and Baker, 2008 1996).…”

“…An additional fossil record of Uria was described from the late Pleistocene of Maine by Marsh (1872). Uria affinis lacks any characters that differentiate it from modern species of Uria and may represent a fossil occurrence of one of those modern forms (Smith and Clarke, 2011). However, the occurrence of Uria lomvia in the Pliocene of Alaska pre-dates the occurrence of Uria affinis, and therefore, Uria affinis should not be considered for use as a fossil calibration.…”

“…Phylogenetic Justification. Alca and Pinguinus have been recovered as sister taxa in the results of analyses of morphological and molecular sequence data (Strauch 1985, Chandler 1990aMoum et al 2002;Baker et al 2007;Pereira and Baker 2008;Smith and Clarke, 2011;Smith and Clarke, in press 1996). The earliest records of Pinguinus are from the Early Pliocene (4.4 Ma) of North Carolina (Olson and Rasmussen, 2001;Smith and Clarke, 2011).…”

“…The name of this taxon was changed to Alca antiqua by Olson and Rasmussen (2001) to reflect its affinities with that clade, and subsequently amended to Alca grandis by Olson (2007) because the name Alca antiqua was unavailable according to the international code of zoological nomenclature (International Commission on Zoological Nomenclature, 2000). Although the holotype specimen of Alca grandis cannot be definitively assigned an age because its exact provenience is not known, the age of Alca grandis is now considered to be Early Pliocene (~4.4 Ma) rather than middle Miocene (11.6 Ma) based on the abundant remains of this taxon from the Pliocene Yorktown Formation of Beaufort County, North Carolina (Olson and Rasmussen, 2001;Smith and Clarke, 2011). "The extension of the temporal range of an extant species into the Miocene prompts questions about both the longevity and diagnosability of species, though no discrete differences in size or morphology between Miocene and Pliocene fossils attributed to A. torda and extant A. torda specimens were noted in specimens examined."…”

Endocranial Anatomy of the Charadriiformes: Sensory System Variation and the Evolution of Wing-Propelled Diving

“…Subsequently, environmental adaptability was recently raised as a potential contributing factor in the considerable species richness ( n  = 7 spp.) documented in Alca during the Pliocene [65]. However, the species exemplar from the most species-rich extant alcid clade, the auklets (Aethiini; represented by the Crested Auklet Aethia cristatella ), displayed the lowest encephalization quotient among volant alcids (Table 3).…”