Therefore , in 1898 , he reclassified it as a species of Protostega , P. ischyros .
After more work reconstructing the specimen , Wieland noticed that its plastron was very similar to that of Protostega gigas and he began to doubt that Archelon was truly distinct .
In 1898 , Wieland reclassified it as a species of Protostega gigas , P. ischyros .
After more work reconstructing the specimen , Wieland noticed that its plastron was very similar to that of Protostega gigas and he began to doubt that Archelon was truly distinct .