Traditional view:  Insectivorans represent primitive
This presentation is the property of its rightful owner.
Sponsored Links
1 / 16

Traditional view: Insectivorans represent primitive eutherian stock. PowerPoint PPT Presentation


  • 38 Views
  • Uploaded on
  • Presentation posted in: General

Traditional view: Insectivorans represent primitive eutherian stock. Original classification of Insectivora (mid-1800s): Elephant shrews Treeshrews Flying lemurs Erinaceidae Solenodontidae Soricidae Talpidae Chrysochloridae Tenrecidae. Insectivora.

Download Presentation

Traditional view: Insectivorans represent primitive eutherian stock.

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Traditional view insectivorans represent primitive eutherian stock

Traditional view: Insectivorans represent primitive

eutherian stock.


Traditional view insectivorans represent primitive eutherian stock

Original classification of Insectivora (mid-1800s):

Elephant shrews

Treeshrews

Flying lemurs

Erinaceidae

Solenodontidae

Soricidae

Talpidae

Chrysochloridae

Tenrecidae

Insectivora


Traditional view insectivorans represent primitive eutherian stock

Original classification of Insectivora (1866):

Elephant shrews

Treeshrews

Flying lemurs

Erinaceidae

Solenodontidae

Soricidae

Talpidae

Chrysochloridae

Tenrecidae

Cecum present: Order Menotyphla

Cecum absent: Order Lipotyphla


Traditional view insectivorans represent primitive eutherian stock

Original classification of Insectivora (1900s):

Elephant shrews: Order Macroscelidea

Treeshrews: Order Scandentia

Flying lemurs: Order Dermoptera

Erinaceidae

Solenodontidae

Soricidae

Talpidae

Chrysochloridae

Tenrecidae

Cecum absent: Order Lipotyphla

(but use of “Insectivora” continued)


Traditional view insectivorans represent primitive eutherian stock

Late 1900s: Is Lipotyphla a natural group?

Lipotyphla

Proposed synapomorphies

(Butler 1988):

Maxillary expansion in orbit

Mobile proboscis

Reduced jugal

Hemochorial placenta

Reduced pubic symphysis

Cecum absent


Traditional view insectivorans represent primitive eutherian stock

Maxillary expansion in orbit (preventing contact of palatine & frontal)

frontal

maxilla

palatine

BUT, golden moles, some tenrecs

don't have expanded maxilla.

Hedgehog

Opossum


Traditional view insectivorans represent primitive eutherian stock

2.Mobile proboscis

present in

some...

absent in others...

and PRESENT in

many non-lipotyphlans


Traditional view insectivorans represent primitive eutherian stock

3.Reduced jugal

BUT, small jugals in hedgehogs may

represent ancestral condition in

eutherians.

Jugal reduction in other lipotyphlans

not well understood.


Traditional view insectivorans represent primitive eutherian stock

some moles

shrews,

some moles

Tenrecs, golden moles, hedgehogs, solenodons

(& some primates, bats, rodents...)


Traditional view insectivorans represent primitive eutherian stock

5.Reduced pubic symphysis

BUT, reduced symphysis found

in most fossorial mammals.

"Reduced" difficult to categorize.

ilium

pubis

connected with cartilage only; no bony fusion


Traditional view insectivorans represent primitive eutherian stock

Cecum:

1st part of large intestine

2 primary functions:

Microbial breakdown of partially

digested food

Recover moisture from

digesting food

In general, faunivores have simple

gut tubes (animal prey easier to

digest).

Ancestral eutherian condition

uncertain.

small

intestine

large

intestine


Traditional view insectivorans represent primitive eutherian stock

Herbivore

Carnivore

Insectivoran


Traditional view insectivorans represent primitive eutherian stock

DNA sequence data:

Lipotyphla is non-monophyletic!

Whales & dolphins

Artiodactyls

Artiodactyls

Carnivorans

Pangolins

Perissodactyls

Bats

Solenodons

Moles

Shrews

Hedgehogs

Primates

Treeshrews

Colugos

Lagomorphs

Rodents

Xenarthrans

Golden moles

Tenrecs

Elephant shrews

Aardvarks

Dugongs & manatees

Hyraxes

Elephants


Traditional view insectivorans represent primitive eutherian stock

Plate tectonics separate N. & S. supercontinents

Laurasia

Gondwana


Traditional view insectivorans represent primitive eutherian stock

Whales & dolphins

Artiodactyls

Artiodactyls

Northern hemisphere radiation

(‘Laurasiatheria’)

Carnivorans

Pangolins

Perissodactyls

Bats

Solenodons

Moles

Shrews

Hedgehogs

Primates

Treeshrews

Colugos

Lagomorphs

Rodents

Xenarthrans

Golden moles

Tenrecs

Elephant shrews

Southern hemisphere radiation

(‘Afrotheria’)

Aardvarks

Dugongs & manatees

Hyraxes

Elephants


Traditional view insectivorans represent primitive eutherian stock

Parallel adaptive radiations on N. & S. supercontinents:

Afrotheria

Laurasiatheria

Whales & dolphins

Artiodactyls

Artiodactyls

Carnivorans

Pangolins

Perissodactyls

Bats

Solenodons

Laurasiatheria

Moles

Shrews

Hedgehogs

Primates

Treeshrews

Colugos

Lagomorphs

Rodents

Xenarthrans

Golden moles

Tenrecs

Elephant shrews

Afrotheria

Aardvarks

Dugongs & manatees

Hyraxes

Elephants


  • Login