The Morphological Evolution and Geographic Distribution of Spheniscus

penguins

Ashley Drexel & Claire Patterson

Basic Penguin Characteristics

Flightless Strong paddle-like wings for propulsion

Counter-shaded Dark on dorsal surface, white on

ventral Varying patterns among

speciesLarge head, short neck, &

elongated body adapted for swimming

Salt excreting glands

Emperor (Aptenodytes)

Fairy (Eudyptula)

Why are they flightless?

Wing support Weight to wing area ratio

Food availability Readily available food in

marine and terrestrial environments resulting in no need for extensive flights for search for food.

As a result, natural selection played a significant role in making them flightless.

Alternative function Water propulsion by

flippers

Smithsonian 2010

Geographic Distribution

Living species are classified in six clearly defined genera: Antarctica/cool temperate waters

Aptenodytes Eudyptes Pygoscelis

New Zealand Megadyptes

Australia/New Zealand Eudyptula

South America, Southern Africa, & the Galapagos Islands Spheniscus

Geographic Origin

Post continental drift As a result of continental drift, two land masses were

formed from Pangea: Gondwana and Laurasia Gondwana contained modern day South America,

Africa, Antarctica, India and Australia Location of modern day penguins’ roots

Phylogenetic Origin

Order Procellariformes Oldest fossilized penguin found dates back to 60

million years ago Records show clear evidence that penguins evolved

from a flying ancestor

Family: Spheniscidae

Spheniscus magellanicus (Magelllanic)

Spheniscus demersus (Jackass/African)

Spheniscus humboldti (Peruvian)

Spheniscus mendiculus (Galapagos)

Spheniscus Species

Nest Eggs

Twigs seaweed, roots 2 greenish eggs

Young Incubation

2 38-41 days

Height Weight

63cm,25in 2.1-4.9 Kg

Home Season

Coastal Southern Africa Nov-Mar

Jackass, African (Spheniscus demersus) Nest Eggs

Caves and crevices and burrows in sand 2 eggs

Young Incubation2 About 40 days

Height Weight68cm, 27in 4.1-5.8 Kg

Home SeasonWest Coast South

America All year

Peruvian (Spheniscus humboldti)

Nest EggsA burrow up to 3m

(10ft) deep Pebbles, twigs, leaves,

etc

2 white eggs

Young Incubation2 About 28 days

Height Weight70cm, 28in 4.9-7.9 Kg

Home SeasonFalkland Islands and

Coastal Patagonia Oct

Magellanic (Spheniscus magellanicus)

Nest Eggs

A few stones 2 white eggs

Young Incubation2 38-40 days

Height Weight50cm, 20in 1.7-2.8 Kg

Home Season

Galapagos Islands All Year

Galapagos (Spheniscus mendiculus)

Where Are They Now?

ga (Galapagos Islands) Spheniscus mendiculus

saf (South Africa) Spheniscus demersus

sam (South America) Spheniscus magellanicus, Spheniscus humboldti

ga

sam

saf

How has the evolution of Spheniscus penguins’ morphology changed to help them survive in warmer

climates?

Featherless patches surrounding head

Feather erectors Autonomic regulation Air pockets between

feathers and skin act as insulators as in fiber glass insulation in the attic of your house

Air sacs Excellent Insulator

Fatty layer under the skin

How has the evolution of Spheniscus penguins’ morphology changed to help them survive in warmer

climates?....(continued)

Body size More surface area

warmer the climate Less surface area cooler

the climate Metabolism

Penguins are like us Homeotherms

Lowers body temperature to reduce heat loss when entering water

Smithsonian 2010

Spheniscus Morphology

Works Cited

Raikow, Robert J., Lesley Bicanovsky, and Anthony H. Bledsoe. “Forelimb Joint Mobility and the Evolution of Wing-Propelled Diving in Birds”. The Auk. July 1988: Vol 105, 446-451. 

Baker, Allan J.. "Multiple gene evidence for expansion of extant penguins out of Antarctica due to global cooling". Proceedings of the Royal Society October 2005: Vol 273, 11-17.

Olson, Storrs. "Fossil Counterparts of Giant Penguins from the North Pacific". Science November 1979: Vol 206, 688-689. 

Croxall, J.P.. "Penguins: Paradoxes and Patterns". Marine Onithology 1999: Vol 27, 1-12. 

Grant, Stewart W.. "Allozyme Phylogeny of Sphenicus Penguins". The Auk 1994: 716-720. 

Bertelli, Sara, Noberto P. Giannini. "A phylogeny of extant penguins (Aves: Sphenisciformes) combining morphology and mitochondrial sequences". Cladistics 2005: 209-239.

http://tuxxie.org/evolution/fossil-penguins.html  http://earthguide.ucsd.edu/penguins/  

QUESTIONS?????