| 词条 | Merriamosauria |
| 释义 |
| taxon = Merriamosauria | fossil_range = Middle Triassic - Late Cretaceous | image = Shastasaurus pacificus.jpg | image_caption = A partial skull of Shastasaurus pacificus, a species which defines the clade Merriamosauria | authority = Motani, 1999 | subdivision_ranks = Subgroups | subdivision =
}}Merriamosauria is an extinct clade of ichthyosaurs. It was named by Ryosuke Motani in his 1999 analysis of the relationships of ichthyopterygian marine reptiles and was defined in phylogenetic terms as a stem-based taxon including "the last common ancestor of Shastasaurus pacificus and Ichthyosaurus communis, and all of its descendants." The name honours John Campbell Merriam.[1] Based on this definition, Merriamosauria includes most ichthyosaurs except for several Triassic groups such as the clade Mixosauria, the family Cymbospondylidae, and perhaps the family Toretocnemidae. Merriamosaurs are characterized by features in their pectoral girdles and limb bones, including an extensive connection between the scapula and the coracoid bone, the absence of the first metacarpal and the absence of a pisiform bone.[1] In addition to Shastasaurus, this clade includes Shonisaurus, Guizhouichthyosaurus, an unnamed Norian taxon from Alaska, and many other genera.[2] References1. ^1 {{Cite journal | last1 = Motani | first1 = R. | title = Phylogeny of the Ichthyopterygia | doi = 10.1080/02724634.1999.10011160 | journal = Journal of Vertebrate Paleontology | volume = 19 | issue = 3 | pages = 473–496 | year = 1999 | pmid = | pmc = }} {{Ichthyosauria|Basal}}{{Taxonbar|from=Q3784620}}{{ichthyosaur-stub}}2. ^{{Cite journal|last=Druckenmiller|first=Patrick S.|last2=Kelley|first2=Neil|last3=Whalen|first3=Michael T.|last4=Mcroberts|first4=Christopher|last5=Carter|first5=Joseph G.|date=2014-09-19|title=An Upper Triassic (Norian) ichthyosaur (Reptilia, Ichthyopterygia) from northern Alaska and dietary insight based on gut contents|url=http://dx.doi.org/10.1080/02724634.2014.866573|journal=Journal of Vertebrate Paleontology|volume=34|issue=6|pages=1460–1465|doi=10.1080/02724634.2014.866573|issn=0272-4634}} 5 : Ichthyosaurs|Middle Triassic ichthyosaurs|Late Triassic ichthyosaurs|Middle Triassic first appearances|Turonian extinctions |
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。