Mammals lab exam 1

Skull

All the bones of the head. The cranium is the top part and the mandible is the lower jawbone.

Premaxilla

A pair of small cranial bones at the very front and center of the upper jaw. Holds the incisors

Maxilla

A pair of fused facial bones that form the upper jaw, hard palate (front portion of the mouth), and parts of the eye sockets and nasal cavity

Zygomatic arch

Cheekbones

Cervical vertebrae

Neck vertebrae

Atlas

First cervical vertebrae. Distinctly wide-winged with a large hole.

Axis

Second cervical vertebrae. Very pointy. Odontoid process is the central axle upon which the head and the atlas can rotate around. Very flat dorsal surface

Thoracic vertebrae

Vertebrae of the upper back

Ribs

Attached posteriorly to the thoracic vertebrae

Lumbar vertebrae

Lower back vertebrae

Sacrum/sacral vertebrae

come after the lumbar vertebrae and can fuse together to make up the back of the pelvis. Not fused in all mammals (especially marine mammals)

Caudal vertebrae

The vertebrae that make up the tail

Scapula

Shoulder blades

Humerus

Upper arm bone

Radius

Lower arm bone that is connected to the thumb

Ulna

Lower arm bone that is not connected to the thumb.

Carpals

Wrist (base) bones of the hand

Metacarpals

Palm bones of the hand (closer to phalanges).

Phalanx/phalanges

Bones of the digits.

Pelvis

Formed by two hip bones. Connected to the sacral vertebrae. Connects the trunk to the lower limbs.

Femur

Large, upper leg bone

Tibia

Large lower leg bone. Shin bone

Fibula

Smaller lower leg bone. Calf bone

Tarsals

Ankle bones. Make up the hind foot and the mid foot

Metatarsals

Long, forefoot bones

Astragalus

One specific, individual tarsal bone at the front of the foot

Calcaneum

Heel bone. Also a tarsal bone

Baculum

Penis bone

Axial skeleton

Skull, spine, ribs

Appendicular skeleton

Scapula, limbs, pelvis

Articulation of the dentary and squamosal bones

Mammalian jaw articulation

Articulation of the quadrate and articular bones

Non-mammalian jaw articulation

3

How many inner ear bones mammals have.

Tribosphenic molar

Basic molar shape of mammals. Has three major cusps arranged in a triangle.

Heterodont dentition

Multiple tooth types within the mouth (as compared with homodont teeth, which are all generally the same shape and size).

Carnassials

Paired, self-sharpening upper and lower teeth made for shearing. Many carnivores have them. Modified molars and/or premolars.

Dental formula

A way of notating how many of each tooth type is on one side of the mouth on both the top and bottom.

Diphyodont dentition

Two sets of teeth: baby and adult.

Diastema

A gap between the front teeth (incisors and canines) and the cheek teeth (premolars and molars).

Monotremata

Prototheria. One of the three main groups of mammals. Some of the oldest mammals. Lay eggs and feed their young with milk secreted from tufts of fur at mammary glands.

Metatheria

Marsupials.

Eutheria

Placentals

Placental mammals

Mammals whose embryos develop inside the mother’s uterus and gain nutrients from her placenta

Auditory bullae

Hollow, bubble-like structure on the bottom side of the top of the skull. Protects the middle ear cavity and bones. Very large in placentals and greatly reduced in marsupials and monotremes.

Semelparity

A reproductive strategy in which an organism puts all its energy into a single reproductive episode and then dies after. Some male marsupials do this.

Syndactyly

A condition where two or more digits are used or webbed together under the skin. Marsupial feet are often of this condition. (This is a contrast to didactyls, which have all unfused digits.)

Cloaca

A single exit from reproductive, excretory, and digestive tracts. Characteristic of most birds and reptiles, and monotremes.

Marsupium

Abdominal pouch found on females for carrying and nursing juveniles. Not fully formed in all marsupials, and present in some mammals that aren’t marsupials.

Epipubic bones

Protrusions/articulations on the pelvis that project forward and toward the skull (anteriorly and cranially/superiorly). Both monotremes and marsupials have these

Mysticeti/mysticetes

Baleen whales. Use plates of baleen to strain their food, which is primarily tiny organisms like krill.

Odontoceti/odontocetes

Toothed whales. Have peg-like teeth used to consume food. Use echolocation.

Cetacea

Whales! The sister group to hippos. Once their own order, they’re now grouped with artiodactyls in the order Cetartiodactyla.

Hyperphalangy

A limb with extra segments added within each digit; increase in bones per digit; makes a digit longer.

Polydactyly

Extra digits are added to the limb; increase in number (rather than length) of digits.

Ungulates

Hooved, mostly herbivorous animals. Walk on ungular phalanges.

Digitigrade

Foot posture where an animal walks on their digits (like cats).

Plantigrade

Foot posture where the animal walks on its entire planar surface (including the metacarpals/tarsals) (like humans).

Unguligrade

Foot posture where the animal walks on its ungual phalanges.

Ungual phalanx

The most distal phalanx. In ungulates, it’s covered by a hoof capsule.

Artiodactyl

Even-toed ungulate

Perissodactyls

(Mostly) odd-toed ungulates.

Paraxonic

A type of foot symmetry where the axis of symmetry runs between digits III and IV. Characteristic of artiodactyls.

Mesaxonic

A type of foot symmetry where the axis of symmetry is on the large center digit (digit III). Characteristic of perissodactyls.

Foregut fermentation

Many-chambered stomachs to digest the cellulose they eat. Characteristic of artiodactyls.

Hindgut fermentation

Digestion of cellulose-rich food occurs in the cecum after the stomach. Characteristic of perissodactyls.

Double pulley astragalus

Locks the ankle into a strict front-to-back hinge, preventing side to side motion Provides joint stability and allows for spring-like responsive mechanical motion. Characteristic of artiodactyls.

Headgear

Catch-all term for the ornamentations growing from the heads of artiodactyls.

Antler

Exposed live bone that is initially covered in vascularized tissue called velvet that eventually sheds. Bone sheds and is regrown yearly. Found in the family cervidae.

Ossicones

Bony growths covered in skin and fur that grow to short lengths and remain for the lifetime of the animal.

Horn

A core of live bone covered in keratin and other proteins. Keratin sheath grows layer by layer. Neither the bone nor the keratin are ever shed. Only true forms in bovidae.

Pronghorn

Bony projections covered with a keratinous sheath that is shed each year (bone core does not shed). Only found in the American pronghorn antelope.

Cannon bone

One long, heavy-duty bone shaft that originated from fusing together the metacarpals/tarsals. Formed mostly from the third metacarpal/tarsal (the rest become vestigial). The bone is weight bearing, is longer to allow for stride extension, and is able to withstand large force from running.

Graviportal

Having a body structure adapted to bearing great weight, usually through thick, squat bones and columnar posture.

Cursorial

Skeleton adapted to running (contrast to a graviportal skeleton).

Hypsodont

Having very tall-crowned teeth that erupt for a long time (because of how tall they are) even though their root is closed. An adaptation to deal with a grinding diet that constantly wears teeth down.

Hypselodont

Indeterminant growth of teeth, where the root is never closed. Contrast to hypsodont teeth. An adaptation to deal with a grinding diet that constantly wears teeth down.

Orthogenesis

Steady, directional, progressional type of evolution. The evolution of horses generally exhibits this.