Basal mammals: Guess what they evolved to become.

Can you guess
(or do you know) which of these taxa evolved to become a human? a killer whale? a rabbit? a giraffe? a bat? a pangolin?

Figure 1. Can you guess which of these taxa evolved to become a human? a killer whale? a rabbit? a giraffe?

Figure 1. Can you guess which of these taxa evolved to become a human? a killer whale? a rabbit? a giraffe?

H. Onychodectes – basal to all large herbivorous mammals, including giraffes.

G. Maelestes – basal to tenrecs and toothed whales.

F. Tupaia – basal to the gnawing clade including rodents and rabbits.

E. Ptilocercus – basal to Primates, including humans (but note the loss of all premaxillary teeth in this extant taxon).

D. Palaechthon – basal to flying lemurs, bats and pangolins.

C. Monodelphis – basal to all placental mammals.

B. Asioryctes – basal to Monodelphis and all placental mammals.

A. Eomaia – basal to all therian mammals (placentals + marsupials).

These are the basalmost taxa
in various clades of Eutherian (placental) mammals. Not a lot of difference to start (which makes scoring difficult). So much potential at the end. Eomaia goes back to the Early Cretaceous, so it’s not difficult to imagine the radiation of these taxa throughout the Cretaceous.

This falls in line with
the splitting of the African golden mole (Chrysochloris) from its South American sister, Necrolestes, a diversification, migration and split that had to happen before Africa split from South American in the Early Cretaceous.

Sharp-eyed readers
will note the re-identification of bones and teeth in Palaechthon, Ptilocercus and Tupaia. It’s been a long weekend trying to figure out long-standing problems in this portion of the LRT. Some of these taxa were some of the first studied and my naiveté was the source of the earlier disinformation, now corrected. If you see any errors here, please advise and, if valid, repairs will be made.

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Birds in the LRT with suggested nomenclature

Figure 1. Subset of the LRT focusing on birds. Names here are traditional, but do not follow traditional definitions.

Figure 1. Subset of the LRT focusing on birds. Names here are traditional, but do not follow traditional definitions.

Just a moment to update
the bird subset of the large reptile tree (LRT, 1151 taxa). Given the present taxon list, this is the order they fall into using the generalized characters used throughout the LRT. The names applied here are used in traditional studies, but perhaps not following previous definitions. If this cladogram can be validated by other morphological studies, then perhaps these clade names can retain their usefulness.

Does anyone see
in this list two ‘related’ taxa that do not resemble one another more so than any other taxon? If so, that needs to be noted and repaired.

Theropods in the LRT with suggested nomenclature

Figure 1. Lately the two clades based on two specimens of Compsognathus (one much larger than the other) have merged recently.

Figure 1. Lately the two clades based on two specimens of Compsognathus (one much larger than the other) have merged recently. Names posted here are in use traditionally, but with different definitions in some cases.

Just a moment to update
the theropod subset of the large reptile tree (LRT, 1151 taxa). Given the present taxon list, this is the order they fall into using the generalized characters used throughout the LRT. Validation is required for all such first-time proposals. The names applied here are used in traditional studies, but often not following previous definitions or clade memberships.

The large and small Compsognathus specimens
are closely related, but not congeneric (Fig. 2).

Figure 1. The large (from Peyer 2006) and small Compsognathus specimens to scale. Several different traits nest these next to one another, but at the bases of two sister clades. Note the differences in the forelimb and skull reconstructions here. There may be an external mandibular fenestra. Hard to tell with the medial view and shifting bones.

Figure 2. The large (from Peyer 2006) and small Compsognathus specimens to scale. Several different traits nest these next to one another, but at the bases of two sister clades. Note the differences in the forelimb and skull reconstructions here. There may be an external mandibular fenestra. Hard to tell with the medial view and shifting bones.

Does anyone see
in this list two ‘related’ taxa that do not resemble one another more so than any other taxon? If so, that needs to be noted and repaired.

I was looking for a long-legged crow…

But I only found a grackle.

Then I started looking
for a long-legged crow/grackle for the large reptile tree (LRT, 1151 taxa), because basal Euornithes are all long-legged, terrestrial birds. Grackles/crows were short-legged exceptions that needed a long-legged ancestor.

Figure 1. Oedicnemus longirostris (= Burhinus oedicnemus?) the long-sough long-legged crow/grackle, the Eurasian stone curlew or thick knee.

Figure 1. Oedicnemus longirostris (= Burhinus oedicnemus?) the long-sough long-legged crow/grackle, the Eurasian stone curlew or thick knee.

I finally found one.
It’s the Eurasian stone curlew (Burhinus oedicnemius) aka? thick-knee (maybe previously known as: Oedicnemius longirostris, Fig. 1).

Oedicnemus longirostris (aka?: Burhinus oedicnemus Linneaus 1758) is the extant Eurasian stone curlew or thick-knee. Length: up to 46cm. Large yellow bulging eyes are adaptations to nocturnal hunting of small tetrapods and invertebrates. Long legs and a terrestrial lifestyle are primitive for all neognath, euornithine birds. This taxon is derived from a sister to Ciconia and basal to grackles, like Quiscalus (below) as well as the Aramus and Threskiornis clades. Note the tiny pedal digit 1.

I was also looking for a megapode.
Any megapode. Could not find skeletal material on the Internet. The good folks at the Smithsonian sent me some bits and pieces. That solves yet another phylogenetic problem.

References
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

wiki/Common_grackle
wiki/Corvus
wiki/Blue_jay
wiki/Eurasian_stone-curlew

Flamingo teeth

Figure 1. The picture says it all. Like ducks and Pelagornis, pseudo teeth appear in flamingos. Here they are used for filtering. Compare these jaws to those of the right whale, Balaena.

Figure 1. The picture says it all. Like ducks and Pelagornis, pseudo teeth appear in flamingos. Here they are used for filtering. Compare these jaws to those of the right whale, Balaena.

No, they’re not real teeth,
But they act like baleen to filter out tiny brine shrimp and blue-green algae. According to Wikipedia, “Their bills are specially adapted to separate mud and silt from the food they eat, and are uniquely used upside-down. The filtering of food items is assisted by hairy structures called lamellae which line the mandibles, and the large rough-surfaced tongue.”

Figure 2. Phoenicopterus, the flamingo, sometimes enjoys the beach.

Duck teeth
(Fig. 3) are not real teeth either.

Figure 3. Anas, the mallard duck, shares more trait with Aepyornis than with other taxa in the LRT.

Figure 3. Anas, the mallard duck, shares more trait with Aepyornis than with other taxa in the LRT.

Pelagornis teeth
(Fig. 4) are not real teeth either. But, brother they look ral.

Figure 1. Pelagornis skeletal elements.

Figure 4. Pelagornis skeletal elements.

Hesperornis teeth|
(Fig. 5) are real teeth.

Figure 2. Hesperornis skull. Compare this to that of Pelagornis in figure 1.

Figure 5. Hesperornis skull. Compare this to that of Pelagornis in figure 1.

Oscar Reig: a paleoprophet separates archosaurs from lepidosaurs in 1967

But… for the wrong reasons.

Reig 1967 prophetically wrote:
“Archosaurs and lepidosaurs apparently have different origins; the former come from the pelycosaurs, and the latter come from the captorhinomorph cotylosaurs through the Millerettiformes.”

Considered heretical at the time,
Reig’s pronouncement echoes in the large reptile tree (LRT, 1151 taxa).

Here’s the full abstract:
“The characteristics of the first archosaurs, the proterosuchian thecodonts, show that neither of the supposed common ancestors of archosaurs and lepidosaurs could actually be an ancestor of archosaurs. Instead, the evidence seems to indicate that the archosaurian ancestors are probably in the ophiacodont-varanopsid group of the pelycosaurian synapsids. In particular, the Varanopsidae are strongly indicative of proterosuchian relationships, as they have evolved some characters which are elsewhere found only in archosaurs. Archosaurs and lepidosaurs apparently have different origins; the former come from the pelycosaurs, and the latter come from the captorhinomorph cotylosaurs through the Millerettiformes.”

The only thing he got wrong
(as everyone else got wrong until seven years ago) was not splitting the Varanopsidae into the Synapsida and the Prodiapsida, as demonstrated in the LRT. He also thought proterosuchids arose directly from varanopsids like Varanodon (Fig. 1), which converge with proterosuchids in size and skull shapes. There’s even an antorbital fenestra, or elongated naris and a drooping premaxilla in Varanodon. No wonder Reig got excited.

Figure 1. Varanodon the synapsid compared to its analog, Proterosuchus, the archosauriform.

Figure 1. Varanodon the synapsid compared to its analog, Proterosuchus, the archosauriform.

Archosauriforms do arise from
former
varanopsids, like Heleosaurus and Mycterosaurus, but not directly. They have to pass through the diapsid grade, then the basal terrestrial younginiform grade before evolving into proterosuchids.

Lepidosaurs do arise from
captorhinomorphs and millerettids in the LRT, but again, not directly. First they have to pass through the nycteroleterid, owenettid, and basal lepidosauriform grades before evolving into lepidosaurs.

The LRT recovered
two clades of diapsids one closer to lepidosaurs and another closer to archosaurs.

References
Reig OA 1967. Archosaurian reptiles: a new hypothesis on their origins.
Science 157(3788):565-8.

Harrisonavis and the origin of flamingos

Harrisonavis croizeti (Torres et al. 2015, Fig. 1) is very clearly an Oligocene flamingo.  Other than the angle of its beak, it is a close match to the living flamingo, Phoenicopterus (Fig. 1).

Figure 1. Click to enlarge. Candidate taxa in the ancestry of flamingos. Most bird experts like long-necked Paleolodus, a tinamou in the LRT. Ignored is Cariama, which shares more traits with flamingos in the LRT.

Figure 1. Click to enlarge. Candidate taxa in the ancestry of flamingos. Most bird experts like long-necked Paleolodus, a tinamou in the LRT. Ignored is Cariama, which shares more traits with flamingos in the LRT.

The trouble comes when you try to delve deeper into flamingo ancestry.
Bird experts, like Mayr 2004, say Palaelodus (Fig. 2 ) is the next outgroup to flamingos. Well, in a way, it is, but the large reptile tree (LRT, 1051 taxa, Fig. 2) nests Palaeodus with Struthio, the ostrich, just outside of the clade that starts with Phoenicopterus, the flamingo, and Cariama, the seriema. So, it’s a close one! Palaelodus was the last of the flying ostriches. All of the basalmost neognaths had long, stilt-like legs.

Figure 1. Subset of the LRT focusing on birds. Here various aspects of birds are shown, including age, teeth, feeding behavior and basic clades.

Figure 2. Subset of the LRT focusing on birds. Here various aspects of birds are shown, including age, teeth, feeding behavior and basic clades.

Figure 1. Nearly proportioned like its giant descendant, Palaeotis was an Eocene ostrich less than 1/3 as tall.

Figure 3. Nearly proportioned like its giant descendant, Palaeotis was an Eocene ostrich less than 1/3 as tall. Compare to Palaelodus.

References
Linnaeus C von 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.
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.
Mayr G 2004. Morphological evidence for sister group relationship between flamingos (Aves: Phoenicopteridae) and grebes (Podicipedidae). Zoological Journal of the Linnean Society. 140 (2): 157–169. doi:10.1111/j.1096-3642.2003.00094.x. ISSN 0024-4082.
Molina JI 1782. Saggio sulla Storia Naturale del Chili. Bologna, Stamperia di S. Tommaso d’Aquino. 349 pp.
Olson SL and Feduccia A 1980. Relationships and evolution of flamingos (Aves: Phoenicopteridae). Smithsonian Contributions to Zoology 316: 1–73.
Torres CR, De Pietri VL, Louchart A and van Tuinen M 2015. New cranial material of the earliest filter feeding flamingo Harrisonavis croizeti (Aves, Phoenicopteridae) informs the evolution of the highly specialized filter feeding apparatus. Organisms, Diversity & Evolution. DOI: 10.1007/s13127-015-0209-7

wiki/Seriema
wiki/Flamingo
wiki/Phoenicopteridae