{"title":"Cranial ornamentation of a large Brachydectes newberryi (Recumbirostra: Lysorophia) from Linton, Ohio.","authors":"Arjan Mann","doi":"10.18435/VAMP29341","DOIUrl":"https://doi.org/10.18435/VAMP29341","url":null,"abstract":"Although the cranial anatomy of the lysorophian tetrapod Brachydectes has been reported in detail recently, many attributes of the group are inadequately known, and lysorophian systematics remain unclear. One under-described aspect of the genus is the development and variation of cranial ornamentation. Whereas the smallest skulls (< 5 mm in length) lack sculpturing, ornamentation increases in progressively larger specimens and is conspicuous in the largest (> 30 mm skull length) individuals. It includes rugose ornament on the anterior cranial roof elements (frontals and anterior parietals) and pustular ornament on the posterior elements (posterior parietals and postparietals). Such ornamentation is unique within recumbirostrans and is identified as an ontogenetic feature.","PeriodicalId":256887,"journal":{"name":"Vertebrate Anatomy Morphology Palaeontology","volume":"179 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133491398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Allometric growth in the skull of Tylosaurus proriger (Squamata: Mosasauridae) and its taxonomic implications","authors":"R. Stewart, Jordan C. Mallon","doi":"10.18435/VAMP29339","DOIUrl":"https://doi.org/10.18435/VAMP29339","url":null,"abstract":"Ontogeny—the growth and development of an organism—is among the more poorly understood aspects of the life history of mosasaurs, largely owing to a dearth of fossil material from young individuals. We describe the partial and complete skulls of two subadult individuals of the mosasaurid Tylosaurus proriger from the upper Smoky Hills Chalk Member of the Niobrara Formation in Kansas. We include the more complete of the two specimens in an allometric analysis to better understand proportional changes of the skull through growth. Although our small sample size produces several instances of ‘soft isometry’, we recover the length of the edentulous rostrum as significantly negatively allometric, and quadrate height as significantly positively allometric. In light of our findings, we go on to consider the question of whether T. kansasensis represents an immature ontogimorph of T. nepaeolicus, but find no convincing evidence that this is the case.","PeriodicalId":256887,"journal":{"name":"Vertebrate Anatomy Morphology Palaeontology","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116669397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Response to Brownstein (2018) ‘Rebuttal of McFeeters, Ryan and Cullen, 2018’","authors":"Bradley McFeeters, Michael J. Ryan, T. Cullen","doi":"10.18435/VAMP29343","DOIUrl":"https://doi.org/10.18435/VAMP29343","url":null,"abstract":"<jats:p>n/a</jats:p>","PeriodicalId":256887,"journal":{"name":"Vertebrate Anatomy Morphology Palaeontology","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133728046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Rebuttal of McFeeters, Ryan and Cullen, 2018, ‘Positional variation in pedal unguals of North American ornithomimids (Dinosauria, Theropoda): A Response to Brownstein (2017)’","authors":"C. Brownstein","doi":"10.18435/VAMP29340","DOIUrl":"https://doi.org/10.18435/VAMP29340","url":null,"abstract":"The Arundel Clay of Maryland is among the only Early Cretaceous terrestrial units known from eastern North America. Research on some theropod dinosaur bones from this layer has indicated the presence of two ornithomimosaur taxa in the assemblage. However, a recent paper discussed issues with the definite assignment of any of these unguals to Ornithomimosauria and suggested that morphological differences originally interpreted to be indicative of the presence of two ornithomimosaurs could be explained by positional variation. Here, I show that substantial evidence persists for the presence of two ornithomimosaurs in the Arundel Clay assemblage, even considering the recent description of positional variation in ornithomimosaur pedal unguals. Furthermore, the argument against the confident assignment of these unguals to ornithomimosaurs is shown to be based on oversimplified comparisons that do not take into account the combination of features in the Arundel specimens that allow for their assignment to that clade. Although several small points made in the initial paper describing the Arundel specimens are incorrect or unsubstantiated, the differences between the Maryland unguals are outside the spectrum of positional variation and are indicative of the presence of two ornithomimosaurs in the Arundel Clay assemblage.","PeriodicalId":256887,"journal":{"name":"Vertebrate Anatomy Morphology Palaeontology","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129458719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}