Carnivora Flashcards
Chapter 16
What defines these two suborders?
anatomy of auditory bulla
- Feliforms: tympanic and endotympanic (2 separate bones with septum
- Caniforms: only tympanic bone (one bone, no septum)
Sub.O. Feliformia – cats, mongooses, civets, genets, hyenas, aardwolves
Sub.O. Caniformia – dogs, bears, weasels, raccoons, skunks, red pandas, three types of aquatic carnivores (walrus, eared seals, true seals)
What does this difference in auditory bulla represent?
No septum in caniforms
Feliforms: tympanic and endotympanic bones (with septum)
Caniforms: only tympanic bone (no septum)
Does the red or yellow represent the geographical distribution of Carnivora?
- exists on all continents except Antarctica and Australia
- Have been introduced into Aus (dingo)
- a wide range of habitats, from desert to arctic
Carnivora synapomorphies
- enlarged P4/m1 – carnassial pair
- canines large, conical
- skulls heavily built, strong zygomatic arch
- braincase enlarged
- large brain relative to body size
- C-shaped mandibular fossa
- prominent sagittal crest
- large, complex turbinals
- simple stomach
- strong, agile body often adapted for running
- acute senses
- most have odor producing scent glands
What is the difference between creodonts and true carnivores?
Creodonta:
- early carnivorous mammals (but not true carnivores)
- Late Cretaceous through Miocene
True Carnivores:
- Appeared Late Paleocene
- P4/m1 carnassial pair
- most modern families appear by Ogliocene
- Diversification of prey groups at the same time as diversification of carnivores
- true carnivores did not evolve from creodonts
- creodonts died out because of competition with other carnivores
How do you define a true carnivore (as opposed to a creodont)?
carnassial teeth
P4/m1 carnassial pair
What does the size of the P4 premolar tell you about the animal’s diet?
- carnassial pair specialized for capturing, killing, and eating other vertebrates
- well-developed conical canine teeth and carnassial teeth
- present regardless of diet
- more carnivorous animals have larger P4s
What is the diet of this animal?
- temporalis muscle and coronoid process are well-developed
- strong vertical bite for grabbing and holding prey
- moderate masseter muscle
- not much mastication
- large bony crests (sagittal) for attachment of temporalis muscle
- indicate large and powerful jaw muscles
Why would this C-shaped mandibular fossa be useful to a carnivore?
- C-shaped mandibular fossa where dentary articulates with cranium
- strong jaw joint –> only permits up/down movement
- stronger bite in favor of side-to-side movement
- may be more room for lateral jaw movement depending on diet
Which of these digestive tracts corresponds to a carnivorous animal? What are the characteristics of a carnivore’s digestive tract?
Second digestive tract outlined in red
- simple
- short
- small or absent cecum because meat is easy to digest
How is the skeleton of a carnivorous animal adapted for agility while running?
- loss of the 3rd trochanter on the femur = increase stride length to allow for faster running
- cats: scapula floating in muscle, front limbs not attached to skeleton
- clavicles reduced or lost = more mobility
How are the feet of carnivorous animals modified for running?
- fusion of carpal bones
- may be plantigrade (ursids and procyonids) or digitigrade (canids, hyaenids and felids)
- animals with digitigrade foot posture tend to be good predators, which have to chase and catch prey
- animals with plantigrade foot posture do not do much running
Carnivores have a large brain relative to body size. What synapomorphy does this contribute to?
- very acute senses
- almost all have an excellent sense of smell from large turbinate bones in nose
- auditory bulla modified for improved hearing
- most have excellent vision, including a well-developed tapetum lucidum
- important in diurnal species
- in nocturnal animals, light may reflect back through retina = two chances to capture light
- must be able to outwit, capture, and consume prey items
Most carnivores have odor-producing scent glands. What are they used for, and what parts of carnivore anatomy allow them to use these glands?
- used for defense (skunks) and intraspecific communication (in heat, etc.)
- anal glands are most well-developed in hyaenids, mustelids, mephitids and herpestids
- acute sense of smell to pick up intraspecific signals
Feliformia synapomorphies
- auditory bullae two-chambered – joined by septum
- short rostrum with fewer teeth
- strong, sharp claws (retractile or semi-retractile)
Which of these skulls represents a more carnivorous animal?
Left: Hyena skull
- bone-crushing/carnivorous
- skull massive
- carnassials well-developed, other cheekteeth robust esp. third PM
Right: Aardwolf skull
- myrmecophagous
- skull light
- no carnassials, reduced/simple cheekteeth
