Chiroptera: Phylogenetic Tree

The two main hypotheses that explain the evolution of bats are:

Monophyly hypothesis

Micro bats and megabats are each other closest relatives in an evolutionary sense, meaning that they form a clade. Most scientists believe that they most likely evolved from small gliding mammals of the order Insectivora. This order today includes small rodent like mammals that feed on insects such as shrews or moles.

Diphyly hypothesis

Megabats and microbats evolved independently from two different groups of non-flying mamals. It has been suggested that megabats are more closely related to demopterans & primates than to microbats

How Did Bats Evolve?

Tree reflecting the monophyly hypothesis - Megachiroptera (megabats) & Microchiroptera (microbats) form a clade

Do you think we could be distantly related to bats?

Sources

Paleochiropteryx

Icaronycteris

Adams, Rick Alan. "Ontogeny, Functional Ecology, and Evolution of

Bats." (2000): n. pag. Web.

Pettigrew, J. D. "Wings or Brain? Convergent Evolution in the Origins of Bats."

Systematic Biology 40.2 (1991): 1-199. Web.

Simmons, Nancy B. and Tenley Conway. 1997. Chiroptera. Bats. Version 01

January 1997. http://tolweb.org/Chiroptera/15966/1997.01.01 in The Tree of

Life Web Project, http://tolweb.org/

TIME PERIOD EVOLUTION SPECIATION EVENT

TIME PERIOD EVOLUTION SPECIATION EVENT

Divergent - Evolved from Hassianycteris due to an extensive suite of morphological changes related to foraging behaviors & echolocation

Early Eocene

Population bottleneck, cause debated: Possibly due to thick algal mats on the lake or poisonous fumes from the lake

Middle Eocene

Simmons, N. B. "EVOLUTION: Enhanced: An Eocene Big Bang for Bats."

Science 307.5709 (2005): 527-28. Web.

Earliest known definitive bat,

capable of echolocation,transition from non-volant to volant locomotions predates the late early Eocene epoch.

Its morphological abilities such as hanging upside down, holding onto a tree branch or stone ridge with its hind legs may have been developed due to the demands of an arboreal enviroment. Echolocation and the ability to flight were both developed simultaneously because of their eating habits

56-60 millions ago

(~48 million years ago)

(1) a greatly enlarged cochlea

(2) dorsal articular facet on the scapula

(3) a laterally compressed ventral

process on the manubrium of the sternum

(4) increased development of rib laminae

(5) a threadlike fibula

(6) presence of a calcar

Archaeonycteris

Hassianycteris

The Evolution of Flight

TIME PERIOD EVOLUTION SPECIATION EVENT

TIME PERIOD EVOLUTION SPECIATION EVENT

Middle Eocene

Classified under the superfamily

Icaronycteroidea

Allopatric speciation due to being

classified under the name

Icaronycteroidea

Middle Eocene

This structure evolved independently from Megachiroptera and Microchirotera. Largest known Eocene bat, reaching a wingspan of a half-meter, and body mass of 65g. Fossil fur reveal they were reddish-brown.

A greatly enlarged cochleae evolved prior to the divergence.

Foraged by catching bettles, cockroaches, and other insects in flight (aeral hawking).

(49 million years ago)

(55.8 million years ago)

1.had fragmental skelteon

2. has narrow lower molars

3. doesn't have hypocone on

upper molars

4. sternum is narrow

Chiroptera: Phylogenetic Tree

The Flying Primate Hypothesis

Presented by: Brian, Caitlin, Hassan, and Praysa

Megabat

Flying Lemur