Lithornithidae is an extinct, possibly

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

Paleogene Fossil Birds
/ref> (but see below) group of early

paleognath Palaeognathae (; ) is a infraclass of birds, called paleognaths, within the class Aves of the clade Archosauria. It is one of the two extant infraclasses of birds, the other being Neognathae, both of which form Neornithes. Palaeognathae contain ...

birds. They are known from fossils dating to the Upper

Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), E ...

through the

Middle Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn ...

of North America and Europe, with possible

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

representatives. All are extinct today; the youngest specimen is the currently unnamed SGPIMH MEV1 specimen from the mid-Eocene

Messel Pit The Messel pit (german: Grube Messel) is a disused quarry near the village of Messel ( Landkreis Darmstadt-Dieburg, Hesse) about southeast of Frankfurt am Main, Germany. Bituminous shale was mined there. Because of its abundance of well-preserv ...

site. Lithornithids had long, slender,

bill Bill(s) may refer to: Common meanings * Banknote, paper cash (especially in the United States) * Bill (law), a proposed law put before a legislature * Invoice, commercial document issued by a seller to a buyer * Bill, a bird or animal's beak Plac ...

s for probing. They closely resembled modern

tinamou Tinamous () form an order of birds called Tinamiformes (), comprising a single family called Tinamidae (), divided into two distinct subfamilies, containing 46 species found in Mexico, Central America, and South America. The word "tinamou" come ...

s. They possessed a rhynchokinetic skull with relatively unfused cranial bones, a weakly fused

pygostyle Pygostyle describes a skeletal condition in which the final few caudal vertebrae are fused into a single ossification, supporting the tail feathers and musculature. In modern birds, the rectrices attach to these. The pygostyle is the main compon ...

and a

splenial The splenial is a small bone in the lower jaw of reptiles, amphibians and birds, usually located on the lingual side (closest to the tongue) between the angular and surangular The suprangular or surangular is a jaw bone found in most land ver ...

. The

ungual An ungual (from Latin ''unguis'', i.e. ''nail'') is a highly modified distal toe bone which ends in a hoof, claw, or nail. Elephants and ungulates have ungual phalanges, as did the sauropods and horned dinosaurs. A claw is a highly modified ungual ...

s were more curved than in tinamous and probably allowed better perching in trees. The order Lithornithiformes was erected by Dr. Peter Houde in 1988. Initially, only three

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

(''

Lithornis ''Lithornis'' is a genus of extinct paleognathous birds. Although ''Lithornis'' was able to fly well, their closest relatives are the extant tinamous (which are poor flyers) and ratites (which are flightless birds). Fossils of ''Lithornis'' a ...

'', ''

Paracathartes ''Paracathartes'' is a genus of extinct bird from the Wasachtian horizon of lower Eocene Wyoming. One species, ''Paracathartes howardae'' has been described. It is a paleognathous bird, turkey-like in stature and size, that probably resembled ...

'', and ''

Pseudocrypturus ''Pseudocrypturus'' is a genus of extinct paleognathous bird. One species is known, ''Pseudocrypturus cercanaxius''. It is a relative of such modern birds as ostriches. It lived in the early Eocene. The holotype fossil is in the collection of th ...

'') and eight named species were included. ''

Promusophaga ''Lithornis'' is a genus of extinct paleognathous birds. Although ''Lithornis'' was able to fly well, their closest relatives are the extant tinamous (which are poor flyers) and ratites (which are flightless birds). Fossils of ''Lithornis'' a ...

'' (Harrison & Walker, 1977) originally considered a stem-

turaco The turacos make up the bird family Musophagidae ( "banana-eaters"), which includes plantain-eaters and go-away-birds. In southern Africa both turacos and go-away-birds are commonly known as loeries. They are semi-zygodactylous: the fourth ( ...

, is considered synonymous with ''

vulturinus''. '' Fissuravis'' may also belong to the clade, and several unnamed remains are known.

Taxonomy

Lithornithiformes Houde, 1988Mikko's Phylogeny Archiv

*†Lithornithidae Houde, 1988 (False tinamous) **†''

Calciavis grandei ''Calciavis'' is an extinct genus of bird from the Eocene of Wyoming. It is a lithornithid, a member of a lineage of flying palaeognaths, distantly related to modern ratites. Like many other fossils from the Green River Formation, it is exception ...

'' Nesbitt, 2016 **†'' Fissuravis weigelti'' Mayr, 2007 **†''

Paracathartes howardae ''Paracathartes'' is a genus of extinct bird from the Wasachtian horizon of lower Eocene Wyoming. One species, ''Paracathartes howardae'' has been described. It is a paleognathous bird, turkey-like in stature and size, that probably resembled ...

'' Harrison, 1979 (Early Eocene of WC US) **†''

Pseudocrypturus cercanaxius ''Pseudocrypturus'' is a genus of extinct paleognathous bird. One species is known, ''Pseudocrypturus cercanaxius''. It is a relative of such modern birds as ostriches. It lived in the early Eocene. The holotype fossil is in the collection of th ...

'' Houde, 1988 **†''

'' Owen, 1840 [''

'' Harrison & Walker, 1977; ''Pediorallus'' Harrison, 1984; ''Parvigyps'' Harrison & Walke,r 1977] (Paleocene – Early Eocene) ***†''Lithornis celetius, L. celetius'' Houde, 1988 ***†'' L. plebius'' Houde, 1988 ***†'' L. promiscuous'' Houde, 1988 ***†'' L. nasi'' (Harrison, 1984) Houde, 1988 'Pediorallus_nasi''_Harrison,_1984.html" ;"title="Pediorallus_nasi.html" ;"title="' 'Pediorallus_nasi''_Harrison,_1984">Pediorallus_nasi.html"_;"title="'Pediorallus_nasi">'Pediorallus_nasi''_Harrison,_1984***†''Lithornis_hookeri.html" ;"title="Pediorallus nasi">'Pediorallus nasi'' Harrison, 1984">Pediorallus_nasi.html" ;"title="'Pediorallus nasi">'Pediorallus nasi'' Harrison, 1984***†''Lithornis hookeri">L. hookeri'' (Harrison, 1984) Houde, 1988 [''Pediorallus hookeri'' Harrison, 1984] ***†''Lithornis vulturinus, L. vulturinus'' Owen, 1840 [''Parvigyps praecox'' Harrison & Walker, 1977; ''Promusophaga magnifica'' Harrison & Walker, 1977; '' Pediorallus barbarae'' Harrison & Walker, 1977a] (London Clay Early Eocene of England) Several studies have shown conflicting status on the monophyly of the group. Some studies recover them as a paraphyletic assemblage leading to modern paleognaths, but more recent examinations group them in a single, natural group basal to the rest of Palaeognathae. Of issue is ''

'', which differs radically from other lithornithids and has been suggested to more closely related to extant paleognaths,Houde, Peter W. (1988). "Paleognathous Birds from the Early Tertiary of the Northern Hemisphere". Publications of the Nuttall Ornithological Club (Cambridge, MA) though it is recently recovered as a derived lithornithid. ''

'' itself may be paraphyletic in relation to ''

'' and ''

''.

Paleobiology

In a study about

ratite A ratite () is any of a diverse group of flightless, large, long-necked, and long-legged birds of the infraclass Palaeognathae. Kiwi, the exception, are much smaller and shorter-legged and are the only nocturnal extant ratites. The systematics ...

endocasts, ''Lithornis'' ranks among the taxa with well developed olfactory lobes. This is consistent with a nocturnal, forest-dwelling lifestyle, though as much all volant birds it retains large optical lobes. Unlike modern tinamous, at least ''

'' has toe claws and reversed halluxes that allow for efficient perching. Several egg fossils have been attributed to lithornithid birds. Both ''

'' and ''

'' have entire nests assigned to them. Their eggshells are, perhaps unsurprisingly, noted as being "ratite-like". Studies on lithornithid feathers shows that some species had gloss similar to that of

cassowaries Cassowaries ( tpi, muruk, id, kasuari) are flightless birds of the genus ''Casuarius'' in the order Casuariiformes. They are classified as ratites (flightless birds without a keel (bird anatomy), keel on their sternum bones) and are native t ...

. Lithornithids, much like modern paleognaths, ibises and shorebirds, had a vibrotactile bill tip organ, suggesting the development of this feature in the Cretaceous.

Notes

References

External links

* Christa Lesté-Lasserre
Bird beak extra sense evolved more than 70 million years ago
on: NewScientist, 2 December 2020 {{Taxonbar, from=Q19169 Paleognathae Paleogene birds of Europe Bartonian extinctions Paleogene birds of North America Prehistoric bird families