Its type species was originally classified as " Ichthyornis celer " . " A . celer " was long allied with " Ichthyornis ", having been assigned to Ichthyornidae by Marsh ( 1873 ), to Odontotormae by Marsh ( 1880 ), and to Ichthyornithiformes by Sepkoski ( 2002 ) . " Apatornis " differs from " Ichthyornis " primarily in that it had at least one additional rib attached to the hip vertebrae ( sacrum ), possibly more as the entire synsacrum was not preserved in the only known specimen . " Apatornis " also lacked the ossified tendons covering the top of the sacral region in " Ichthyornis ".
मोबाइल