title: Evolution: One Penis After All.
abstract: Amniote penises come in many shapes but are missing from the basal tuatara. This has been taken as evidence for multiple evolutionary origins of the penis. Now, genital swellings have been found in tuatara embryos, arguing for a single origin.
authors.affiliation: Department of Biological Sciences, Mount Holyoke College, South Hadley, MA 01075, and Division of Organismal and Evolutionary Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA. Electronic address: pbrennan@mtholyoke.edu.
authors.forename: Patricia L R
authors.initials: PL
authors.lastname: Brennan
mesh_terms: D000818:Animals; D005075:Biological Evolution; D019143:Evolution, Molecular; D008297:Male; D010413:Penis; D012104:Reptiles