ichthyopterygia造句

• Other ichthyosauriforms were the Ichthyopterygia, containing the Ichthyosauria and allies.
• Basal Ichthyopterygia have a parietal eye opening between the paired parietal bones.
• Basal Ichthyopterygia still have two sacral vertebrae but these are not fused.
• In 1840, Richard Owen named an order Ichthyopterygia as an alternative concept.
• Motani found it to be more basal than the Ichthyopterygia and named an encompassing clade Ichthyosauriformes.
• It has generally been considered an ichthyopterygian until Motani ( 2000 ) showed that it lacks the basal synapomorphies of Ichthyopterygia.
• Like the Ichthyopterygia, the Hupehsuchia have a pointed snout and show polydactyly, the possession of more than five fingers or toes.
• A basal ichthyosauriform is " Cartorhynchus "; more derived species are part of the Ichthyopterygia which again include the Ichthyosauria.
• The removal / inclusion of Ichthyopterygia was found to affect the topology the most-switching the positions of the " Eusaurosphargis " + " Helveticosaurus " and Thalattosauriformes clades, and altering the positions of several taxa within Eosauropterygia, which are not shown.
• These very early " proto-ichthyosaurs " had such a distinctive build compared to " ichthyosaurs proper " that Motani excluded them from the Ichthyosauria and placed them in a basal position in a larger clade, the Ichthyopterygia ( Motani 1997, Motani et al . 1998 ).
• Ichthyosaurs belong to the order known as "'Ichthyosauria "'or "'Ichthyopterygia "'('fish flippers' a designation introduced by Sir Richard Owen in 1840, although the term is now used more for the parent clade of the Ichthyosauria ).