AMNIOTE LUNGS
EVOLUTION OF FORM AND FUNCTION
The primary focus of the Schachner Lab is the evolution of the amniote respiratory system. We are using methods from various different scientific disciplines to gain insight into the anatomy and physiology of the lungs of extant sauropsids and with these data, attempt to reconstruct the evolutionary history of one of the most morphologically diverse vertebrate organs.
PULMONARY STRUCTURAL DIVERSITY in REPTILES & BIRDS
Our research group is currently focused on the following questions:
1) Why is there so much structural diversity in the sauropsid respiratory system?
2) What is the evolutionary history of the respiratory system in Sauropsida?
3) What are pulmonary diverticula in reptiles and birds for?
4) How does the environment impact the avian respiratory system?
Methods:
1) Anatomy: CT, µCT, latex and gross dissection, 2D/3D geometric morphometrics, classic morphometrics
2) Development in zebra finches and ducks
3) Paleontology: diversity surveys & secondary inferences, validation of osteological correlates
4) Functional studies: ultrasound, airflow measurements, computational fluid dynamic (CFD) modeling
ANATOMICAL APPROACH
A collaborative project with Brandon Hedrick (Cornell University) looking at the ecomorphology of extant crocodilian and avian lungs using qualitative and quantitative methodologies.
Phylogeny for Diapsida showing the lung anatomy of the various groups.
The 3D anatomy of the savannah monitor lizard, and idealized image of flow patterns
Proposed homology between the crocodilian and the bird.
Partial bronchial tree of the Nile crocodile (the dorsobronchi and ventrobronchi). In: Schachner et al., 2013. PeerJ (see publication list)
Dorsal view of the bronchial tree and shell of a common snapping turtle (Chelydra serpentina)
Alligator mississippiensis
Alligator mississippiensis vs. Crocodylus niloticus
Diagrammatic airflow patterns in the crocodilian and the bird.
CT scanning hawks with University of California Berkeley Graduate Student Jessie Atterholt (Wake lab)
Postprandial and fasting
Full bronchial tree model segmented by former Schachner Lab student Dr. Adam Lawson
Parrot vs ostrich
DEVELOPMENTAL APPROACH
A joint project with Raul Diaz (Cal State LA) is aimed at investigating lung and skeletal development in various non-model taxa and chickens.
PALEONTOLOGICAL APPROACH
Examination of the thoracic rib and vertebral anatomy of extant archosaurs indicates a relationship between the postcranial axial skeleton and pulmonary anatomy allowing for predictions of the respiratory morphology of extinct taxa. The data from this research thus far suggest a progression from a dorsally immobile thin-walled lung in basal dinosauriform archosaurs towards a small volume-constant avian-style lung in saurischian dinosaurs. A continuation of the project is focused on pseudosuchians.
FUNCTIONAL APPROACH
What is the purpose of non-ventilatory diverticula? Are they involved in ventilation? Locomotion, vocalization?