#lithornis

Lithornis vulturinus preening, using a partridge as pose reference

DAWN OF THE PALEOGNATHS!!!

IT HAS BEGUN!!!

YOU'RE IN FOR IT NOW MOTHER FUCKERS!!!

So, let's explain to the kids in the peanut gallery, that aren't obsessed with bird taxonomy and evolution, what a Paleognath is...

This is an infraclass of birds that are considered to be "primitive" in their anatomy. They have primitive more reptilian palates, and they have penises (which is something most other birds have lost through evolution), as well as some other anatomical traits. Primitive, meaning they have some traits of earlier birds.

We don't use the term living fossil here at the blog, as every living thing today is the result of 4 billion years of evolution, and has changed and adapted and continues to do so.

Paleognaths probably diverged from other groups of birds in the Early Cretaceous.

Some people confuse this grouping with the ratites (ostriches, rheas, cassowaries, emus), but the ratites are a group of paleognaths. (What I'm trying to get across here is that the other paleognath birds I'm going to name are not ratites, they're just closely related).

There has been some dispute over the years as to whether the Paleognathae are polyphyletic (not actually evolutionary closely related but different groups that we have grouped for the sake of ease and similar traits). Recent anatomical and genetic analysis strongly favors them being monophyletic (an actual single closely related evolutionary lineage).

Most members of this group are flightless.

Here are the groups of Paleognaths:

Ostriches

Rheas

Cassowaries and Emus

Kiwis

Tinamous

Elephant Birds (extinct)

Moas (extinct)

Lithornids (extinct, may be polyphyletic)

Masai or East African Ostrich (Struthio camelus massaicus), male, family Struthionidae, order Struthioniformes, Masai Mara, Kenya

A subspecies of the Common Ostrich.

The largest species of bird in the world, standing up to 8.86 ft (2.7 m) tall.

Flightless.

photograph byKmb Prasad

Greater Rhea (Rhea americana), family Rheidae, order Rheiformes, found in central and eastern South America

Flightless

Standing up to 5 ft 7 in tall

photograph by Rufus46

Emu (Dromaius novaehollandiae), family Casuariidae, order Casuariiformes, Flinders Ranges, SA, Australia

Flightless

Standing up to 6.25 ft (1.91 m) tall.

photograph by Greg Wisnia

Southern Cassowary (Casuarius casuarius), father with eggs, family Casuariidae, northern Australia

Flightless

Standing up to 1.9 m (6 ft 3 in) tall.

Photograph by VestorStudio

Puna Tinamou (Tinamotis pentlandii), family Tinamidae, order Tinamiformes, found in Puna (high altitude grassland) in the Southern Andes Mountains of South America.

The tinamous are an ancient group of birds, related to ratites (ostriches, rheas, emus, and cassowaries).

Though they are not strong flyers, they are capable of flight.

photograph by Luke Seitz

North Island Brown Kiwi (Apteryx mantelli), Apterygidae, order Apterygiformes, widespread in the northern 2/3 of the North Island of New Zealand

VULNERABLE.

photograph by Tui de Roi

Elephant Bird (Aepyornis maximus), family Aepyornis, order Aepyornithiformes, Found in Madagascar

EXTINCT (Sometime around 1000 AD)

These huge birds reached a height of up to 3 (9.8 ft), and a weight of up to 1,000 kg (2,200 lb).

illustration by George de Lodge

South Island Giant Moa (Dinornis robustus), family Dinornithidae, order Dinornithiformes, was found on the South Island of New Zealand

EXTINCT.

Flightless

Possible the tallest bird species to have existed, standing up to 3.6 metres (11 ft 10 in) tall.

images: Joseph Smit & Paleoneolitic

Lithornis, family Lithornidae, order Lithorniformes, known from Upper Paleocene through the Middle Eocene

Capable of flight

6 species

A Lithornis father with two chicks

Quantitative analysis of stem-palaeognath flight capabilities sheds light on ratite dispersal and flight loss

Klara Widrig, Fabio Alfieri, Pei-Chen Kuo, Helen James and Daniel J. Field

Abstract

Lithornithids are an assemblage of Palaeogene fossil birds thought to represent stem-group members of Palaeognathae. Among extant palaeognaths, which include flightless ratites such as ostriches, only tinamous can fly, though only in anaerobic bursts. Despite their limited dispersal capabilities, the phylogenetic interrelationships and geographic distributions of palaeognaths imply that their early relatives were capable of long-distance dispersal, although quantitative skeletal evidence has not been applied to this question. We investigate the flight capabilities and ecology of the Palaeogene lithornithid Lithornis promiscuus using a three-dimensional geometric morphometric dataset spanning the avian crown group. Our models reject the hypothesis that Lithornis would have relied on tinamou-like burst flight, and show that its sternum morphology is consistent with a range of aerobic, flapping flight styles—closely resembling those of many extant birds exhibiting pronounced dispersal capabilities. Our results are consistent with inferences from lithornithid wing shape, supporting the hypothesis that at least some stem palaeognaths were capable of long-distance flight, helping to clarify the origins of the transoceanic distributions of extant flightless ratites.

Read the paper: