{"title":"The veritable horns of a dilemma: Assessing homology of the parietal and squamosal asperities of Phrynosoma (Squamata: Iguania: Phrynosomatidae)","authors":"G. Lawrence Powell, Anthony P. Russell","doi":"10.1111/azo.12454","DOIUrl":null,"url":null,"abstract":"<p>Members of the genus <i>Phrynosoma</i> all exhibit asperities upon the parietal and squamosal. We examined μ-CT scans of the dermatocrania of ontogenetic series of all but two of the species of <i>Phrynosoma</i>, and defined parietal and squamosal “horns”, distinguishing them from tubercles. We counted parietal and squamosal horns and used phylogenetic analysis to reconstruct the plesiomorphic horn numbers for these bones. Based upon this, we propose and test hypotheses of evolutionary homology for these asperities and conclude the following: (1) a plesiomorphic horn array is retained among the species of <i>Phrynosoma</i>; the horns are paramorphs, each identifiable as an evolutionary homologue; (2) an autapomorphic additional pair of parietal horns in <i>P. solare</i> has been recruited from a pair of tubercles associated with the plesiomorphic parietal horns; (3) an additional anterior squamosal horn in <i>P. solare</i> and the Brevicauda species is derived from a tubercle recruited homoplasiously in these taxa; (4) the anteriormost squamosal horn of the plesiomorphic series in the species of the <i>coronatum</i> species group is highly reduced and is subsumed within the posteriormost jugal asperity and (5) an apparent additional squamosal horn exhibited by <i>P. ditmarsi</i> and <i>P. modestum</i> is instead an enlarged submarginal tubercle, a homoplasy for these species.</p>","PeriodicalId":50945,"journal":{"name":"Acta Zoologica","volume":"105 1","pages":"57-80"},"PeriodicalIF":1.1000,"publicationDate":"2023-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Acta Zoologica","FirstCategoryId":"99","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1111/azo.12454","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"ANATOMY & MORPHOLOGY","Score":null,"Total":0}
引用次数: 1
Abstract
Members of the genus Phrynosoma all exhibit asperities upon the parietal and squamosal. We examined μ-CT scans of the dermatocrania of ontogenetic series of all but two of the species of Phrynosoma, and defined parietal and squamosal “horns”, distinguishing them from tubercles. We counted parietal and squamosal horns and used phylogenetic analysis to reconstruct the plesiomorphic horn numbers for these bones. Based upon this, we propose and test hypotheses of evolutionary homology for these asperities and conclude the following: (1) a plesiomorphic horn array is retained among the species of Phrynosoma; the horns are paramorphs, each identifiable as an evolutionary homologue; (2) an autapomorphic additional pair of parietal horns in P. solare has been recruited from a pair of tubercles associated with the plesiomorphic parietal horns; (3) an additional anterior squamosal horn in P. solare and the Brevicauda species is derived from a tubercle recruited homoplasiously in these taxa; (4) the anteriormost squamosal horn of the plesiomorphic series in the species of the coronatum species group is highly reduced and is subsumed within the posteriormost jugal asperity and (5) an apparent additional squamosal horn exhibited by P. ditmarsi and P. modestum is instead an enlarged submarginal tubercle, a homoplasy for these species.
期刊介绍:
Published regularly since 1920, Acta Zoologica has retained its position as one of the world''s leading journals in the field of animal organization, development, structure and function. Each issue publishes original research of interest to zoologists and physiologists worldwide, in the field of animal structure (from the cellular to the organismic level) and development with emphasis on functional, comparative and phylogenetic aspects. Occasional review articles are also published, as well as book reviews.