Notes on The Speculative Dinosaur Project’s Enantiornithes
In keeping with scientific accuracy:
– No retrices. Only tweeties and some Allospiziformes have well developed tail-feathers, and they’re more ribbon-like feathers like those found in longipterygids and kin. I’m considering expanding this to some avisaurids, but generally enants shouldn’t have tails beyond their long pygostyles.
– With the exception of tweeties and Allospiziformes, most have well developed wing claws. Note that the fingers are fused as in euornithes, so there should only be two visible claws.
– With the exception of a few oddballs, most are highly precocial, with at most a week or so of parental care. This doesn’t change from old!Spec.
– There should be some notice to their aerial locomotion. Enantiornithes are pretty much really weird when it comes to sternal and shoulder anatomy, and it’s been made very clear that these things were flying in a radically different way from euornithes. Tweeties might converge with euornithes in flight style, but this depends on whereas interpretations on longipterygid flight resembling that of euornithe birds more than that of other enants is a reasonable assumption or not.
– Most should have hindwings or feathery hindlimbs; no scutes whatsoever. This should be particularly interesting on aquatic forms like ebergs.
Established Enantiornithe clades:
– Gondwanaviformes: weird arboreal sloth-hoatzin things that include the Falsa Panha, global tropical folivores.
– Avisauriformes: the classical “raptors” + the frigatebird-like jarilos.
– Enabaptiformes: grebe-like ebergs. More concepts can be made from these, as it is a pretty underdeveloped clade.
– Twitiaviformes: tweeties and kin. Basically I think they can be invisioned as longipterigids with beaks, though of course some are highly divergent, such as the swift-like mistriders. Speaking of swifts, Spec Apodiformes may be remade into mistriders.
– Allospiziformes: parrot-like forms that are far more speciose than HE parrots, such as finch-like otherworld finches.
A few odd relics can be present here and there, though ideally all modern enants are within these clades, all originating as far back as the Cretaceous.
– Twitiaviformes diverged first; within it Twitiavidae is the most basal (if a valid clade and not a paraphyletic grade), with the remaining four “families” being group as Australoenantiornithes, composed of an Arborogemnidae + Pseudartamidae clade and a Therizinorhynchidae + Balaclavidae clade. Other clades are welcome.
– All other Enantiornithes belong to Euenantiornithes. Enabaptiformes diverged first, followed by Gondwanaviformes; this leaves a clade composed of Avisauriformes + Allospiziformes, something akin to the falcon + parrot + passerine clade within Neornithes.
– Within Avisauriformes, Avisauridae diverged first (again, if a valid clade and not a paraphyletic grade), leaving an Allostrigidae + Eupelagornithidae clade.
– Within Allospiziformes, otherworld finches are well established to be a paraphyletic grade. There may or may not be a crown clade of Civilispizidae + Apatopsittaciformes.