Module 14 Flashcards
Artiodactyla
Describe the evolutionary history and diversification of Artiodactyl herbivores, including extinct and extant lineages.
Tylopoda, Suina, Ruminantia, Hippopotamidae, and Cetacea
Evaluate how environmental changes (e.g. glaciation events, land bridges) influence distribution, extinction, and adaptation in large herbivores.
- Camelid family originated in North America (USA) during the Eocene, spread through Beringia land bridge
Discuss the role of artiodactyls in ecosystems and how their evolutionary history reflects broader patterns in mammalian herbivore evolution.
Artiodactyls (even-toed ungulates) play crucial roles in ecosystems as primary consumers, ecosystem engineers, and prey species, while their evolutionary history reflects key patterns in mammalian herbivore evolution, such as dietary specialization, limb adaptation, and responses to environmental change.
Ecological Roles of Artiodactyls:
Herbivory and Nutrient Cycling:
As dominant grazers and browsers (e.g., deer, antelope, cattle), they shape plant community structure through selective feeding, promoting biodiversity.
Their dung recycles nutrients, enriching soil and supporting decomposer communities.
Prey and Predator Dynamics:
Artiodactyls are a major food source for large carnivores (e.g., wolves, lions), maintaining trophic balance.
Migratory species (e.g., wildebeest) redistribute nutrients across landscapes.
Ecosystem Engineering:
Wallowing (e.g., pigs, hippos) creates microhabitats for aquatic organisms.
Trampling and grazing influence fire regimes by reducing fuel loads (e.g., bison in grasslands).
Seed Dispersal:
Frugivorous species (e.g., peccaries) aid in seed dispersal, fostering forest regeneration.
Evolutionary History and Broader Patterns:
Early Diversification (Paleocene-Eocene):
Artiodactyls arose ~55 mya, diversifying alongside perissodactyls (odd-toed ungulates) during the spread of grasslands.
Developed cursorial (running) adaptations (elongated limbs, reduced digits) for predator evasion in open habitats.
Dietary Adaptations:
Evolved rumination (foregut fermentation in bovids, cervids) for efficient cellulose digestion.
Non-ruminants (e.g., pigs, hippos) retained omnivorous diets, showcasing niche partitioning.
Climate and Habitat Shifts:
The Miocene grassland expansion favored hypsodont (high-crowned) teeth in grazers (e.g., antelopes) to cope with abrasive silica-rich grasses.
Aquatic adaptations (e.g., hippos, cetaceans) demonstrate a major transition from terrestrial to aquatic niches.
Convergent Evolution:
Parallel evolution with perissodactyls (e.g., horses vs. antelopes) in limb structure and grazing adaptations.
Cetacean divergence (whales, dolphins) from terrestrial ancestors (e.g., Pakicetus) illustrates a dramatic shift in habitat and morphology.
Anthropogenic Impact:
Domestication (e.g., cattle, pigs) altered ecosystems through agriculture, while overhunting drove extinctions (e.g., aurochs).
Conclusion:
Artiodactyls exemplify how mammalian herbivores adapt to ecological pressures (climate, predation, diet). Their evolutionary trajectory—from small, forest-dwelling ancestors to diverse grazers, swimmers, and even marine giants—mirrors broader trends in mammal evolution, including specialization, convergence, and resilience to environmental change. Their ecological roles underscore their importance in maintaining ecosystem stability.
Chriacus
A small arctocyonid from the early Palaeocene to early Eocene of North America
Some researchers suggest they may have been ancestral to the Artiodactyla (even-toed mammals), but this is debated.
Chaeropus
An extinct genus of small marsupials known as pig-footed bandicoots.
The evolution of hooves in the extinct pig-footed bandicoot Chaeropus is an example of convergent evolution with the artiodactyls (even-toed ungulates).
Name at least 3 of the 19 modern pigs.
(1) Golden Babirusa
(2) Sulawesi Babirusa
(3) Giant Forest Hog
(4) Desert Warthog
(5) Common warthog
(6) Pygmy hog
(7) Bushpig
(8) Red River Hog
(9) Palawan Bearded Pig
(10) Beard pig
(11) Viet. Wart Hog
(12) Visayan Warty pig
(13) Celebes Warty pig
(14) Flores Warty Pig
(15) Mindoro Warty Pig
(16) Philippine Warty
(17) Javan Warty Pig
(18) Wild Boar
(19) Domestic pig
Two Hippo species?
(1) the common hippopotamus, Nile hippopotamus and river hippopotamus, is a large semiaquatic mammal native to sub-Saharan Africa
(2) the pygmy hippopotamus (Choeropsis liberiensis or Hexaprotodon liberiensis).
Tylopoda?
Tylopoda is a suborder of terrestrial herbivorous even-toed ungulates belonging to the order Artiodactyla.
Extant Members (Family Camelidae)
Camels (Camelus):
Dromedary (1-humped, C. dromedarius)
Bactrian camel (2-humped, C. bactrianus)
New World Camelids (South America):
Llama (Lama glama)
Alpaca (Vicugna pacos)
Guanaco (Lama guanicoe)
Vicuña (Vicugna vicugna)
Extinct Groups
Protoceratidae:
Miocene-Pliocene “pseudo-deer” with facial horns (e.g., Synthetoceras).
Oromerycidae:
Eocene ancestors of camels, small and deer-like.
Xiphodontidae & Anoplotheriidae:
Early artiodactyls with unique limb adaptations.
Key Traits:
✔ Digitigrade padded feet (no hooves, soft foot pads)
✔ Ruminant-like digestion (3-chambered stomach, but not true ruminants)
✔ Adapted to arid/extreme environments (e.g., fat-storing humps, drought resistance)
Camelops
Camelops is an extinct genus of camel that lived in North and Central America from the middle Pliocene to the end of the Pleistocene.
E.g. C. hestemus
Ruminantia: foregut fermentation
- multiple-chambered stomach
- adapted to digesting cellulose
- fermentation occurs before digestion in the stomach in a special rumen (1st stomach chamber)
Ruminants
Tradulidae (Chevrotains, or mouse-deer)
Moschidae (Musk deers; tusked)
Cervidae
Bovidae
Antilocapridae
Giraffidae
Micromeryx
Micromeryx is an extinct genus of musk deer that lived during the Miocene epoch.
Cervidae diversity
The Irish Elk
Bovidae (9)
- Bison antiquus
- Water buffalo
- Ox
- Yak
- aurochs or urus
- domestic cattle
- Hartebeest
- Caprinae (goats, ibex, thar, sheep, mountain goats, muskox)
- Wildebeest
Giraffidae
Extant Giraffidae
- Giraffe (Giraffa camelopardalis)
Subspecies (IUCN Status):
Northern Giraffe (G. c. camelopardalis) – Endangered
Kordofan Giraffe (G. c. antiquorum) – Critically Endangered
Nubian Giraffe (G. c. camelopardalis) – Critically Endangered
West African Giraffe (G. c. peralta) – Vulnerable
Reticulated Giraffe (G. reticulata) – Endangered
Masai Giraffe (G. tippelskirchi) – Endangered
Angolan Giraffe (G. angolensis) – Vulnerable
South African Giraffe (G. giraffa) – Least Concern
(Note: Some classifications split these into 4 separate species: G. camelopardalis, G. reticulata, G. tippelskirchi, and G. giraffa.)
2. Okapi (Okapia johnstoni)
The only other living giraffid, a forest-dwelling relative of giraffes.
Status: Endangered (due to habitat loss and hunting).
Recently Extinct Giraffids
†Sivatherium (Pleistocene): A massive, moose-like giraffid with antler-like ossicones.
†Samotherium (Miocene): Intermediate in size between okapis and modern giraffes.
Antilocapridae
Extant Species
Pronghorn (Antilocapra americana) – The sole surviving member.
Subspecies:
A. a. americana (Common pronghorn)
A. a. mexicana (Mexican pronghorn)
A. a. peninsularis (Baja pronghorn) – Endangered
A. a. sonoriensis (Sonoran pronghorn) – Endangered
Unique Trait: Branched, shedding horns (unlike true antlers/true horns).
Extinct Genera (Notable Examples)
†Capromeryx (Pleistocene): Tiny “dwarf pronghorn” (~1 ft tall).
†Stockoceros (Pleistocene): Four-horned pronghorn.
†Tetrameryx (Pleistocene): Large, with four horns.
†Hayoceros (Pleistocene): Two long, straight horns.
