Basal eutheria Flashcards
Family Chrysochloridae
golden mole
IC Eutheria
SO Afrotheria
O Afrosoricida
- Conical skull
- Complete zygomatic arch
- Molars have a narrow V-shaped cusp pattern
- Has auditory bulla
- No external eyes
- No pinnae
- Forefoot with large claws on 2 or 3 digits
- fossorial, adapted to live entirely underground
- Ethiopian
Which of these is the most fossorial and why?
semi-fossorial shrew
fossorial mole
golden mole
- golden mole seems to be the most fossorial:
- -no external eyes
- -no pinnae
- -forefoot with large claws on 2 or 3 digits, lots of room for muscle attachment on forelimbs
- -adapted to live entirely underground
Family Macroscelididae
elephant shrew
IC Eutheria
SO Afrotheria
O Macroscelidea
- Complete zygomatic arch
- Quadrate molars
- Postorbital bar never complete
- Shrew-like skull except has complete bullae
- long, flexible snout, poor olfaction
- insectivores
- diurnal = well-developed eyes
-Ethiopian
Family Orycteropodidae
aardvark
IC Eutheria
SO Afrotheria
O Tubilidentata
- Homodont cheekteeth
- Rootless, evergrowing columnar cheekteeth, lacking enamel
- –made up of hexagonal prisms of dentine
- –held together with cementum
- –no I’s or C’s
- No incisors or canines
- Complete zygomatic arch
- Elongate skull with long, protrusile tongue
- insectivores
- Ethiopian
Family Elephantidae
elephant
IC Eutheria
SO Afrotheria
O Proboscidea
- Graviportal limbs
- Trunk
- 24 teeth replaced from back to front
- –extremely hypsodont, deep lophs = highly adapted for grazing and eating rough vegetation
- –mammoths have a similar method of tooth replacement
- –mastodons replace teeth in typical mammalian fashion
Family Procavidae
hyrax
IC Eutheria
SO Afrotheria
O Hyracoidea
- incisors are rodent-like
- –Upper incisors triangular in cross-section with enamel on front
- –Tricuspid lower incisors
- Canines absent
- Mesaxonic foot (weight-bearing axis passes through an enlarged 3rd digit)
- postorbital process formed by parietal bones (not frontals as in most other mammals)
- originated in Africa with early proboscideans and sirenians = close relationship despite extreme morphological differences between modern forms
- Ethiopian
Order Sirenia
manatee and dugong
IC Eutheria
SO Afrotheria
- Fusiform body shape
- Flipper-like forelimbs
- Dense bones (pachyostotic)
- –increase body mass to help regulate buoyancy
Family Trichechidae
manatee
IC Eutheria
SO Afrotheria
O Sirenia
- No incisors but functional cheek teeth
- Cheekteeth each have two transverse ridges
- Premaxillae small
- Nasals present
- Tail rounded
Family Dugongidae
dugong
IC Eutheria
SO Afrotheria
O Sirenia
- 1 upper incisor
- Simple columnar cheekteeth
- Premaxillae large
- No nasal bones
- Tail fluke dolphin like (notched)
Xenarthrous articulations
- extra articulation surfaces
- brace trunk vertebrae = add rigidity to axial skeleton
Family Dasypodidae
armadillo
IC Eutheria
SO Xenarthra
O Cingulata
- Homodont cheek teeth
- Elongate skull
- Zygomatic arch complete
- Body covered in horny (keratinized) scutes
- Tibia/fibula fused with expanded muscle insertions
How is the aramdillo skeleton adapted for digging?
-large area for attachment of muscles used in digging
- large processes on the humerus
- spines on the scapula
- long olecranon process on the ulna
- panniculus carnosus: attaches to pelvis and pectoral girdle
- –when contracted draws both ends of the body together like a clam shell
Order Pilosa
IC Eutheria
SO Xenarthra
Families:
Myrmecophagidae (anteaters)
Bradypodidae (3-toed sloths)
Megalonychidae (2-toed sloths)
- Incisors and canines lacking
- Cheek teeth lack enamel
- Xenarthrous articulations of the vertebrae
- Expanded ischium (pelvis)
- Well-developed coracoid and acromion processes
Family Myrmecophagidae
anteater
IC Eutheria
SO Xenarthra
O Pilosa
- Edentate (toothless)
- Elongated downward sloping skull
- Incomplete or absent zygomatic arch
- Can you dig it?
-Neotropical
Family Bradypodidae
3-toed sloth
IC Eutheria
SO Xenarthra
O Pilosa
- Short skull
- Evergrowing cup-like teeth
- Incomplete zygomatic arch
- Forked jugal
- 3 digits on forefeet
- 8-9 cervical vertebrae
- condyle taller than tooth row
sloths in general:
- chambered stomach
- algae grows in fur = camoflauge
- Neotropical
Family Megalonychidae
2-toed sloth
IC Eutheria
SO Xenarthra
O Pilosa
- Longer skull
- Incomplete zygomatic arch
- Forked jugal
- Caniniform premolar and a condyle (carnivoran-like arrangement
- Cup-like teeth
- 2 digits on forefeet
- 5-8 cervical vertebrae
sloths in general:
- chambered stomach
- algae grows in fur = camoflauge
- Neotropical
Family Erinaceidae
hedgehog
IC Eutheria
SO Laurasiatheria
O Erinaceomorpha
- Zygomatic arch complete
- Bunodont molars.
- Pinnae present and well-developed
Family Soricidae
shrew Local spp: Notiosorex crawfordi (Desert Shrew) Sorex monticolus Sorex ornatus Sorex trowbridgii
IC Eutheria
SO Laurasiatheria
O Soricomorpha
- Molars with W-shaped cusp pattern
- –last 4 teeth molariform (P4-M3)
- –teeth between I and P4 are called unicuspid
- No zygomatic arch
- Incisors large and specialized with extra cusps
- –first tooth is an I with two cusps
- –lower I’s projected forward to meet upper I’s for nabbing invert prey
- –dark pigmentation: iron incorporated into enamel
- includes one of world’s smallest mammals
- very high metabolism
- ring-shaped tympanic bone attached to malleus (inner ear bone)
- lack auditory bulla
Notiosorex crawfordi
desert shrew
IC Eutheria
SO Laurasiatheria
O Soricomorpha
F Soricidae
-upper jaw only has 3 unicuspid teeth
Sorex monticolus
long-tailed shrew
IC Eutheria
SO Laurasiatheria
O Soricomorpha
F Soricidae
- Medial cusp on upper incisor
- 3rd unicuspid about ½ size of 2nd
Sorex ornatus
long-tailed shrew
IC Eutheria
SO Laurasiatheria
O Soricomorpha
F Soricidae
- Medial cusp on upper incisor
- only edge/tips of upper incisors pigmented
Sorex trowbridgii
long-tailed shrew
IC Eutheria
SO Laurasiatheria
O Soricomorpha
F Soricidae
- No medial cusp on upper incisor
- pigment on significant portion of upper incisor
- 3rd unicuspid just slightly smaller than 2nd unicuspid
Family Talpidae
mole, desman, shrew mole Local spp: Neurotrichus gibbsii (shrew mole) Scapanus latimanus (broad-footed mole) Scapanus orarius (coast mole) Scapanus townsendi (Townsend's mole)
IC Eutheria
SO Laurasiatheria
O Soricomorpha
- Molars with W-shaped cusp pattern
- Zygomatic arch complete.
- 1st incisor simple, directed downward and backward
- Blocky humerus (almost as wide as long), articulates with scapula and clavicle
- keeled sternum
- Forefoot projects outward and backward with elbow rotating up.
- Broad paddle-like forefoot (falciform bone)
Neurotrichus gibbsii
shrew mole
IC Eutheria
SO Laurasiatheria
O Soricomorpha
F Talpidae
- long hands
- more primative
- unevenly spaced teeth
Scapanus latimanus
broad-footed mole
IC Eutheria
SO Laurasiatheria
O Soricomorpha
F Talpidae
- broad hands
- unevenly spaced unicuspids
- light gray/brown
Scapanus orarius
coast mole
IC Eutheria
SO Laurasiatheria
O Soricomorpha
F Talpidae
- broad hands
- wider spaced unicuspids
- no distinct maxillary ridge
- black/chocolate fur
Scapanus townsendi
Townsend’s mole
IC Eutheria
SO Laurasiatheria
O Soricomorpha
F Talpidae
- broad hands
- wider spaced unicuspids
- distinct maxillary ridge
- black/chocolate fur
Family Manidae
pangolin
IC Eutheria
SO Laurasiatheria
O Pholidota
- Edentate
- Smooth, conical skull
- Complete zygomatic arch
- Overlapping scales (keratinized epidermis) = protection
- Large, recurved claws
- roll into a tight ball when alarmed (panniculus carnosus)
- long tongue muscle attached to pelvis
