The "'Pelecaniformes "'is an order of medium-sized and large waterbirds found worldwide.
12.
Birds of the two genera have 15 cervical vertebrae, unlike almost all other Ciconiiformes, Suliformes and Pelecaniformes, which have 17.
13.
It is most often allied-albeit tentatively-with the Gaviiformes ( loons / divers ), Procellariiformes ( tubenoses ) or Pelecaniformes.
14.
Although the majority are parasites of the Columbiformes, some species from this subgenus have also been reported in the Charadriiformes, Pelecaniformes and Suliformes.
15.
Microscopic analysis of eggshell structure by Konstantin Mikhailov in 1995 found that the eggshells of tropicbirds lacked the covering of thick microglobular material of other Pelecaniformes.
16.
Pelicans are very large water birds with a distinctive pouch under their beak Like other birds in the order Pelecaniformes, they have four webbed toes.
17.
A cladistic study of the skeletal and bone morphology of the classical Pelecaniformes and relatives found that the frigatebirds formed a clade with " Limnofregata ".
18.
In regard to the recent evidence that the traditional Pelecaniformes is polyphyletic, it has been suggested that the group be split up to reflect the true evolutionary relationships.
19.
Recent research strongly suggests that the similarities between the Pelecaniformes as traditionally defined are the result of convergent evolution rather than common descent, and that the group is paraphyletic.
20.
All families in the traditional or revised Pelecaniformes except the Phalacrocoracidae have only a few handfuls of species at most, but many were more numerous in the Early Neogene.
