In the present subset
of the large reptile tree (LRT, 1090 taxa, Fig. 3) flamingoes (genus: Phoenicopterus, Fig. 1) nest with the seriema (genus: Cariama, Fig. 2). That makes the flamingo a sort of bird of prey, now concentrating on tiny plankton (algae + invertebrates). That’s why they are so distinct.
Wikipedia lists several studies
that nest flamingoes with ducks, spoonbills and/or doves.
Prum et al. 2015 used DNA
to nest flamingoes with grebes. These submersible sharp-rostrum, hind limb swimmers have not yet been added to the LRT, but grebes look more like loons, similar to Gavia. Until that analysis, here’s a loon skeleton online. So when grebes are added, I’ll let you know how that works out.
The closest tested relative
of Phoenicopterus in the Prum et al. tree is Uria, the murre, which we looked at yesterday, Here, Uria nests between dippers and penguins, far from Phoenicopterus (Fig. 3).
So, apparently there is no consensus
out there regarding flamingo relatives. Are the flamingo-like traits of Cariama convergent or homologous? The answer has to come from comparative anatomy. DNA fails too often to deliver sisters who actually look like one could evolved from the other or from a common ancestor sharing a long list of traits.
Figure 1. Phoenicopterus, the flamingo, currently and provisionally nests with Cariama in the LRT.
Phoenicopterus chilensis (Molina 1782) is the extant flamingo, a long-legged filter-feeder with pink plumage. Here it ness with Cariama, the seriema.
Figure 2. The seriema (genus: Cariama) is the closest taxa to Yanornis in the LRT. The two resemble one another in most details, but Cariama lacks teeth, has a retracted naris and an elevated pedal digit 1.
Cariama cristatus (Linneaus 1766) is the extant seriema, a grasslands predator from South America. It flies only to escapte predators. Here it is basal to the flamingo, Phoenicopterus. At present it is easy to see why they nest together. And this is where the LRT shines.
Figure 1. Subset of the LRT focusing on birds. Here various aspects of birds are shown, including age, teeth, feeding behavior and basic clades.
If anyone can find a better match
for flamingoes, please let me know. Otherwise, you heard it here first. Meanwhile, I’m surprised to see what I learn in just a few hours has not been discovered before. This is not rocket science.
References
Linneaus C 1766. Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio duodecima, reformata. Holmiae. (Laurentii Salvii).: 1-532.
Molina JI 1782. Saggio sulla Storia Naturale del Chili. Bologna, Stamperia di S. Tommaso d’Aquino. 349 pp.
The Pterosaur Heresies 
