Skull Studies

Skeleton Framework of an animal’s body Gives shape, support, and protection Vertebrates, endoskeleton Muscle attachment allowing for movement Skull portion includes teeth and bone plates

Skeleton is a result of evolutionary change Animal adaptation to their environment Role or niche Analyzing an animal’s skeletal structures of vertebrates Infer its eating habits Environmental lifestyle

The Skull Mammal skulls are made up of two series of bones Paired bones Unpaired bones

Paired Bones of the Skull Back of the skull Parietals, towards the back of the skull Frontals, front of the skull Maxillas, under the eyes Premaxillas, under the nose (not present in humans) Nasal

Underneath the Skull Palatines, roof of mouth

On the Sides of the Skull Zygomatic, cheekbones (squamosal flat, and jugal point) Orbit, protecting the eyes (temporal fossa, opening behind the orbit)

On the Top of the Skull Sagittal Crest, midline toward the rear of the head, develops on the parietals. Temporal muscle attachment.

Unpaired Bones of the Skull Back to Front Occipital Bassioccipital, between the auditory bulla Preshenoid, indention b/w bassiocciptal & palatine Vomer (inner nasal bone, laying on maxilla) Occipital condyles, points of movement between the skull and the backbone Foramen magnum, passes the spinal cord

From the Bottom Auditory bullae, houses the inner ear Rostrum Inside the nasal area there are visible scroll – like convolutions of nasal turbinates Support the moist membranes of the nose

Lower Jaw Mandibles join in the front Back of each side is the mandibular condyle, joined to the skull Coronoid process, tall wing-like area of the jaw where some of the muscles that close the jaw attach

The Teeth Four types of teeth Incisors, 3 lie in the premaxilla Used for nipping and pulling of food Canines, long and curved sharp conical tooth Used for piercing Premolars, sharp and have one main point or cusp Used to grasp and tear Molars, triangular teeth with strong blunt cusp Used for crushing, lower jaw may have fewer molars Carnassial shearing tooth is the first molar in the lower jaw and fourth premolar in the upper jaw (carnivore)

Dental Formula Used to identify species Short hand used to write the dental formula ICPM Fraction show upper then lower teeth for one side Example, Canine I 3/3 , C 1/1, PM ¾, M 3/2

Carnivore Sharp serrated edges to tear and cut flesh Incisors, narrow, smaller teeth, sharp edges Canines, highly developed, longer for gripping and tearing Premolars, twin conical peaks used for cutting Molars, serrated used for cutting

Herbivore Flat molars, no canines or premolars Adaptations in dental structure reflect methods of obtaining food Rodents (Muskrat), gnawing long curved incisors (orange) Browsing (Deer), incisors present in mandible not in maxilla, molars flat and well formed Cropping (Horse), sharp edge incisors both jaws

Omnivore Great variety of sizes and shapes, basic structure is the same Well developed incisors, canines, molars Combination of herbivore and carnivore Humans, bears, pigs

Insectivore Conical narrow teeth for piercing exoskeletons Opossum