Belongs within: Neognathae.
Contains: Accipitriformes, Strigiformes, Coraciimorphae, Cariamiformes, Falconidae, Psittaciformes, Passeriformes.
The Telluraves are a clade identified by molecular analyses that has been known as the ‘higher land birds’. Representatives are uniformly terrestrial with most being adept fliers. They include the birds of prey, historically united as the Falconiformes, though this order in its broad sense is now recognised as polyphyletic. Instead, the Falconidae (falcons) form a clade with the cariamas, parrots and perching birds whereas the remaining ‘Falconiformes’ form a distinct clade. These include the Cathartidae, New World vultures, large soaring scavengers with bare heads and long feet with an elevated hind toe.
The Patagonian land penguin
Published 28 March 2017
Take a good look at the figure above, which comes from Mayr (2009). It shows the fossilised tarsometatarsus (the fused long bone of the foot) of a bird from the late Oligocene of Patagonia. This may be one of the single most mysterious specimens in the fossil record. It represents all we know to date of Cladornis pachypus, described by Argentinean palaeontologist Florentino Ameghino in 1895. The appearance of the bone, being very broad and flat relative to its length, is quite bizarre and does not much resemble the tarsometatarsus of any other known bird.
The first thing that should be pointed out is that, whatever it was, Cladornis was a large bird. The specimen is not completely preserved (part of the proximal end of the bone has been lost) but its overall shape suggests that its original length was probably not too much longer than what we have. As such, the tarsometatarsus was probably comparable in length to that of a large pelican. However, it was much wider relative to length than that of a pelican, suggesting the possibility of a more robust bird. The shape of the bone’s end indicates that the toes would have been widely spaced, and it may have even approached a zygodactyl arrangement (with two toes pointed rearwards and two forwards, like a modern parrot*) (Mayr 2009).
*When explaining this to my partner, I suggested that he imagine a parrot the size of a pelican. He shuddered and declared that he would rather not.
When Ameghino (1895) first described Cladornis, he interpreted it as an aquatic bird and suggested a relationship to the penguins, albeit in an extinct family Cladornidae (later authors would correct this to Cladornithidae). Later, noticing that it was preserved in association with terrestrial mammals, he declared that it was not marine and was possibly even terrestrial (he also included another species from the same formation, Cruschedula revola, in the Cladornithidae; this species is based on part of a scapula and there is no telling if it was related to Cladornis or not). He still maintained its relationship to the penguins (Ameghino 1906). Ameghino had a bit of a thing for trying to find the origins of all major modern vertebrate groups in his native South America (one of his other works was a book arguing for an Argentinean origin of humans) and it is possible that this was in play here. Nevertheless, the idea of a ‘Patagonian land penguin’ held sway until Simpson’s (1946) review of the fossil penguins, in which he declared that Cladornis was “so very unlike any other penguin, recent or fossil, that I can only consider its reference to that group as erroneous“.
This left Cladornis‘ taxonomic position completely up in the air (the question of whether Cladornis itself could get up in the air is, of course, currently completely unswerable). Wetmore (1951) included Cladornis in the Pelecaniformes, because…reasons. The closest he gave to an explanation was, “The only suggestion that has come to me is that possibly they may belong in the order Pelecaniformes, in which I have placed the family tentatively in the suborder Odontopteryges, where it is located with two others of almost equally uncertain status. This allocation is wholly
tentative and is no indication of belief in close relationship in the three diverse groups there assembled“. He would later move Cladornis into its own suborder, Cladornithes, and no close relationship to the ‘Odontopteryges’ (now the Pelagornithidae) has been suggested since. Our current understanding of bird phylogeny finds Wetmore’s remaining ‘Pelecaniformes’ to correspond to three or four independent clades (the Pelecanidae, Suliformes, Phaethontidae and probably Pelagornithidae) so his assignment of Cladornis to this group becomes almost completely uninformative.
Which is pretty much where we’re forced to leave things. Mayr (2009) included Cladornis in his chapter on ‘land birds’, with other taxa discussed in this chapter belonging to the clade Telluraves. However, this was motivated more by a lack of any idea what to do with it otherwise than anything else (it is possible that Cladornis‘ sub-zygodactyly played a role, but not all zygodactylous birds belong to the Telluraves). I did notice a similarity in proportions between the Cladornis tarsometatarsus and the corresponding bone in the large phorusrhacid Brontornis, making me wonder if anyone had ever compared the two, but this may well be only superficial. Most recent authors have assumed that the Cladornis tarsometatarsus is simply too weird, too unique, for any resolution of its affinities to be reached without first finding more complete remains of the animal.
Systematics of Telluraves
<==Telluraves (see below for synonymy)
| i. s.: Oxylophus glandariusS66a
| Masillaraptor parvunguis Mayr 2006M09
| Coturnipes Harrison & Walker 1977M09, Ml02
| `--*C. cooperi Harrison & Walker 1977Ml02
| Mopsitta tanta Waterhouse et al. 2008M09
| Cladornis Ameghino 1895M09, S46 [Cladornidae, Cladornithes, Cladornithidae]
| `--*C. pachypus Ameghino 1895S46
|--+--+--+--AccipitriformesKF-V21
| | | `--Cathartiformes [Cathartae, Cathartoidea]CHP24
| | | |--Teratornithidae [Teratornithi]M09
| | | | |--Argentavis magnificens Campbell & Tonni 1980M09
| | | | |--Taubatornis campbelli Olson & Alvarenga 2002M09
| | | | |--Cathartornis gracilis Miller 1910U93
| | | | `--TeratornisC01
| | | | |--T. incredibilis Howard 1952U93
| | | | `--T. merriami Miller 1901U93
| | | `--Cathartidae [Vulturidae]BKB15
| | | | i. s.: Parasarcoramphus Mourer-Chauviré 2002M05
| | | | `--P. milneedwardsi Mourer-Chauviré 2002M09
| | | | Diatropornis Oberholser 1899M05 [=Tapinopus Milne-Edwards 1892 (preoc.)Ml02]
| | | | `--*D. ellioti (Milne-Edwards 1892) [=*Tapinopus ellioti]Ml02
| | | | Gypagus papaS18
| | | | Catharista urubuS18
| | | | Phasmagyps patritus Wetmore 1927M09
| | | | Brasilogyps faustoi Alvarenga 1985M09
| | | |--+--Coragyps Geoffroy St.-Hilaire 1853CHP24, B94 [Coragypidae]
| | | | | `--C. atratus (Bechstein 1793)CHP24
| | | | `--Cathartes Illiger 1811CHP24, B94
| | | | | i. s.: C. atratusF43
| | | | | C. californianusS66b
| | | | | C. iotaF43
| | | | |--C. aura (Linnaeus 1758)BKB15, L58 [=Vultur auraJ23]
| | | | `--+--C. burrovianusBKB15
| | | | `--C. melambrotusBKB15
| | | `--+--GymnogypsCHP24
| | | | |--G. amplusFP64
| | | | `--G. californianusBKB15
| | | `--+--Sarcoramphus Duméril 1806CHP24, B94 [Sarcoramphidae]
| | | | |--S. gryphusF43
| | | | |--S. papaBKB15
| | | | `--S. sacra [=S. papa sacra]D81
| | | `--Vultur Linnaeus 1758BKB15, B94
| | | |--*V. gryphus Linnaeus 1758B94, C04
| | | |--V. angolensisG42
| | | |--V. fossilis Keferstein 1834Ml02
| | | |--V. harpyja Linnaeus 1758L58
| | | |--V. papa Linnaeus 1758L58
| | | |--V. percnopterus Linnaeus 1758L58
| | | `--V. umbrosus (Cope 1874) [=Cathartes umbrosus]C77
| | `--Horusornis Mourer-Chauviré 1991JM14, Ml02 [Horusornithidae]
| | `--*H. vianeyliaudae Mourer-Chauviré 1991Ml02
| `--+--StrigiformesKF-V21
| `--CoraciimorphaeKF-V21
`--Australaves [Australavis]KF-V21
|--CariamiformesPB15
`--+--FalconiformesCNR16
| |--FalconidaePB15
| `--Antarctoboenus Cenizo, Noriega & Reguero 2016CNR16
| `--*A. carlinii Cenizo, Noriega & Reguero 2016CNR16
`--+--Halcyornithidae [Pseudasturidae]OF19
| |--PseudasturidesM09 [incl. Pseudastur Mayr 1998Ml02]
| | `--P. macrocephalus (Mayr 1998)M09 [=*Pseudastur macrocephalusMl02, M09]
| |--Serudaptus Mayr 2000M09, Ml02
| | `--*S. pohli Mayr 2000Ml02
| |--Halcyornis Owen 1846Ml02
| | `--*H. toliapicus (Koenig 1825)Ml02, M09 [=Larus toliapicusMl02]
| |--Pulchrapollia Dyke & Cooper 2000Ma02
| | |--P. gracilis Dyke & Cooper 2000M09
| | `--P. olsoni (Feduccia & Martin 1976) [=Primobucco olsoni]Ma02
| |--Precursor Harrison & Walker 1977M09, Ml02
| | |--*P. parvus Harrison & Walker 1977Ml02
| | |--P. litorum Harrison & Walker 1977Ml02
| | `--P. magnus Harrison & Walker 1977Ml02
| `--Cyrilavis colburnorumKSW17
`--Psittacopasserae [Passerimorphae]OF19
| i. s.: Morsoravis sedilisKSW17
|--PsittaciformesPB15
`--PasseriformesPB15
Telluraves [Accipitres, Afroaves, Anomalogonatae, Coracii, Coraciides, Diurni, Eutelluraves, Falcones, Falconides, Falconimorphae, Falconoidea, Leptosomatoidea, Picariae, Picoclamatores, Raptores, Trogones, Trogonomorphae, Zygodactyli]
*Type species of generic name indicated
References
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