The Hall of Vertebrate Origins at the American Museum of Natural History is an
impressive collection of fossils and specimens which allow the visitor to see parallel structures
such as wings and flippers evolve over time. While the inner architecture of the ear is often
hidden from view, we can recognize that the environmental pressure to develop them is present
across different habitats, and the investment to develop them in terms of biological resources is
relatively low. Further, vocalizations can be used for a variety of uses such as communication or
mating (Manley 2010). Middle ear structures are excellent features to perform comparative
anatomy on. They assist with the transmission of auditory vibrations to the inner ear, and their
bones can be seen to exhibit evolutionary change. Recently, the exploration of gene expression
also allows for the further understanding of structural origins.
The flat, primitive head of Buettneria is on display in the hall. Buettneria’s auditory
organs are located behind its cheekbones, where it contains semicircular embayments. These are
clearly precursors to amphibian eardrums (Damiani 2001). Buettneria and other temnospondyls
like it were in possession of a small columella that was able to function as a middle ear as well as
a large otic notch (Manley 2010). This single bone connects the inner ear to the eardrum. There
are many indications that the middle ear-precursors of Buettneria are homoplastic, since the
precursors of lepidosaurs and archosaurs were totally lacking a middle ear structure (Manley and
Clack 2004).
In mammals, we can see that the same avenue is arrived at through different means,
namely the repurposing of the articular and quadrate mandible bones. These became not a single
middle ear, but rather three ossicles known as the malleus, the incus, and the stapes. However,
the former two bones are homologus to reptilian structures, and the evidence can be found in
both the fossil record and also in developing fetuses (Bowler 1996). However, Manley claims a
impressive collection of fossils and specimens which allow the visitor to see parallel structures
such as wings and flippers evolve over time. While the inner architecture of the ear is often
hidden from view, we can recognize that the environmental pressure to develop them is present
across different habitats, and the investment to develop them in terms of biological resources is
relatively low. Further, vocalizations can be used for a variety of uses such as communication or
mating (Manley 2010). Middle ear structures are excellent features to perform comparative
anatomy on. They assist with the transmission of auditory vibrations to the inner ear, and their
bones can be seen to exhibit evolutionary change. Recently, the exploration of gene expression
also allows for the further understanding of structural origins.
The flat, primitive head of Buettneria is on display in the hall. Buettneria’s auditory
organs are located behind its cheekbones, where it contains semicircular embayments. These are
clearly precursors to amphibian eardrums (Damiani 2001). Buettneria and other temnospondyls
like it were in possession of a small columella that was able to function as a middle ear as well as
a large otic notch (Manley 2010). This single bone connects the inner ear to the eardrum. There
are many indications that the middle ear-precursors of Buettneria are homoplastic, since the
precursors of lepidosaurs and archosaurs were totally lacking a middle ear structure (Manley and
Clack 2004).
In mammals, we can see that the same avenue is arrived at through different means,
namely the repurposing of the articular and quadrate mandible bones. These became not a single
middle ear, but rather three ossicles known as the malleus, the incus, and the stapes. However,
the former two bones are homologus to reptilian structures, and the evidence can be found in
both the fossil record and also in developing fetuses (Bowler 1996). However, Manley claims a
