1916] Wiman: Marine Triassic Reptile Fauna of Spitzbergen 



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numerous phalanx-like bones of different length, which, as I have pre- 

 viously pointed out, cannot be located in an ichthyosaurian skeleton, 

 but which might possibly belong to the Omphalosaurus teeth. That 

 an ichthyosaurian Pessopteryx should develop a peculiarly formed 

 humerus, which is identically like that of another ichthyosaurian, 

 Pessosaurus, from the same region, is by far not so strange as that a 

 reptile of an altogether different tribe, Omphalosaurus, should acquire 

 just this humerus type. I therefore consider the probability larger 

 that in addition to Pessopteryx nisseri also a representative of the 

 genus Omplialosaunis is before us. 



FAUNAL RELATIONSHIPS 



I can therefore agree with Merriam that the marine Triassic 

 saurians of Spitzbergen and of central and southern Europe show a 

 noticeable similarity with those of the Triassic of North America. 

 The Mixosaurus species nordenskioldi, cornaUanus, and nutans are 

 undoubtedly nearly related. If, then, a separate genus, Phalaradon, 

 be added, common to Spitzbergen and western North America, this 

 of course increases the similarity. Judging by von Huene's previous 

 communications, a number of American ichthyosaurian genera are also 

 to be found in the middle European Muschelkalk. Omphalosaurus, 

 wherever it belongs, is also a genus common to Spitzbergen and North 

 America. 



If, however, important similarities exist between the Triassic marine 

 saurians in the Old and the New World, there are also greater dis- 

 similarities. These differences appear among the ichthyosaurians. In 

 western North America are found numerous species of the genera 

 Cymbospondylus, Toretocnemus, Merriamia, Delphinasaurus, and 

 Shastasaurus, which do not appear in Europe or Spitzbergen. The 

 Central European Muschelkalk no doubt also contains one or two 

 specific types, and Pessosaurus and Pessopteryx are characteristic of 

 Spitzbergen. 



If we turn to other reptile groups that are not adapted to a pelagic 

 mode of living in such a high degree as the ichthyosaurians the dis- 

 similarities of course become greater. In the Alpine Trias two notho- 

 saurians, Pachypleura (Neusticosaurus) from Besano and the some- 

 what younger Lariosaurus of Perledo, are found. In the Middle Euro- 

 pean Muschelkalk are found numerous nothosaurians and placodonts. 

 The marine Trias beds in Spitzbergen also contain several evidently 



