8 Superorder Laurasiatheria - Ungulates Flashcards
What are the “New” mammalian superorders?
Laurasiatheria: Cetartiodactyla, Perissodactyla, Carnivora,
Pholidota, Chiroptera, Eulipotyphla*
Afrotheria: Afrosoricida*, elephant shrews, aardvark, Sirenia,
Hyracoidia, Proboscidea
Xenarthra: Sloths, anteaters, armadillos
Euarchontoglires: Rodents, Lagomorphs, Primates, flying
lemurs, tree shrews
Ungulates (hoofed animals)
What order are odd-toed ungulates?
What order are even-toed ungulates?
How many families are found in each, and give examples?
Where is the origin of the superorder Laurasiatheria?
Order Perissodactyla (odd-toed ungulates)
3 families – 16 spp (Rhinos, Horses, Tapirs)
Order Artiodactyla (even-toed ungulates)
10 families – 187 spp (incl. Antelopes, Deer, Hippopotamus, Pigs, Camels…..)
Recent research indicates that these orders have their origin in the superorder Laurasiatheria
What are the three main adaptations which ungulates have undergone? and how?
- Adapted to a terrestrial lifestyle
- Rapid locomotion via limb modifications
- Herbivorous diet via specilisation in the gut and teeth modifications
Basic limb anatomy of classic pentadactyl limbs:
What becomes enlongated in the ungulates?
The metapodials becomes elongated in the ungulates
Specialisations in limb anatomy in relation to gait, what can the relative position and orientation of these bones tell you?
What is the gait of ungulates?
How do they compare to other mammals, give examples
These bones can describe the way of standing and locomotion.
Ungulates are Unguligrade: they walk on the tips of their toes
The orientation of the metapodial elment dictates the giat
Human are plantigrade because the metapodial element is flat on the ground
Dogs are digitigrade, walking on their digits
Digestion in ungulates – the herbivorous diet
Ungulates show adaptations in:
- Teeth morphology
- Gut
How do ungulates beakdown cellulose?
What is the digestive system of perisodactyles?
What is the digestive system of ruminants - some artiodactyls?
Because of the vegeterian diet, ungulates need to digest cellulose and because mammals dont have the enzymes to break down cellulose (i.e cellulase). They have a symbiotic relationship with bacteria. Bacteria break down the cellulose, releasing fatty acids and sugars, which are then absorbed.
Odd toed ungulates (perissodactyles) digest by hindgut fermentation - bacteria live in the caecum, which is found after the small intestine making the percentage of efficiency ~45%, over 48hours.
Some even-toed ungulates digest by rumination, foregut fermentation, the food is chewed several times, digestion is at the front in thr rumen (where the bacteria are present) which is found before the small intenstine making it more efficient method (60%) of digestion, however it takes up to 80 hours.
Early ungulates:
Condylarthra characteristics?
Examples, which example needs to be remembered
Condylarthra – non-specialist in diet, artificial grouping of several distinct lineages at the base of the radiation of later ungulates – served as a wastebasket taxon - sometimes referred to as protoungulata
–Mesonychids: N. American Palaeocene/Eocene * remember
–Tillodonts: Europe & N. American Palaeocene/Eocene
–Pantodonts: Europe & N. American Palaeocene/Oligocene
–Arctocyonids: Europe & N. American Palaeocene
Early ungulates are thought to have looked like wolves
Which example of condylarthra family examplifies the wolf like morphology
Early artists impression
The mesonychids examplifies the wolf like morphology
they were carnivorous ungulates of the Palaeocene & early Eocene
Mostly wolf-sized with pointed molars for flesh eating
Super-ordinal groupings
What were early ungulates known as?
Within the protoungulata were condylarthra which had four families within it given example of the a family and example of it?
Before there was odd/even toed ungulates there were early ungulates: protoungulata
Within the protoungulata were condylarthra which had four families within it, mesyonychids was one of them and an example of mesyonychids was mesyonyx
What are paenungulata?
Give examples?
Paenungulata are near ungulates
– Elephants (Proboscidea)
– Manatees & dugongs (Sirenia)
– Hyraxes (Hyracoidea)
– Aardvark (Tubulidentata)
Early Perissodactyls
Were the largest mammals that ever exsisted, such as indricotherium (up to 15 tonnes)
What are the two extinct families of early perissodactyls?
The Eocene bronotherids (sister to horses) went extinct in Eocene.
The Eocene chalicotherids went extinct in Pleistocene
What determined the evolution of horses?
What evolved in the horse?
Expantion of grass-lands (environmental change)
Evolution of teeth and limb morphology thought to be driven by environmental change (spread of grassland) in late Oligocene/Early Miocene
Early Artiodactyls - even toed ungulates
Example includes Diacodexis (Eocene: Asia, N. America, Europe) (Rose 1982, 2006)
What are the characteristics of this example?
Small, rabbit-like
5 toes present, but 3 & 4 the longest
Small hooves on toes?
Double-pulley astragalus - which allows controlled bending, between the lower leg and the ankle, and restricts movement to vertical plane.
Highly adapted running mammal for its time
Early Artiodactyls
What is an important adaptation
Double-pulley astragalus
Modern artiodactyls fall into 2 groups
What are the two groups?
Give examples of each?
- Bunodontia/suriformes: pigs & hippos
– 7 or 8 genera
– Triangular section canine teeth
– Bulbous cusps on molars
- Selenodontia: cattle, deer, giraffes, camels & antelopes
More than 70 genera
– Specialised cheek teeth with selenodont pattern – the cusps form crescent-shaped ridges
The perissodactyls are replaced by artiodactyls
Why have the even toed out competed the odd toed?
Even toed out competed the odd toed because of climate change, more grassland and contraction of forests
Because grasses are hard to digest the eficiency difference makes a big impact and there for the even toed (artiodactyls) have an advantage over the odd toed (perissodactyls)
