Related Experiment Video
Updated: Jun 11, 2026
08:02
Dissection and Flat-mounting of the Threespine Stickleback Branchial Skeleton
Published on: May 7, 2016
Using linkage models to explore skull kinematic diversity and functional convergence in arthrodire placoderms
1Geophysical Sciences Department, University of Chicago, Chicago, Illinois, USA. Phil.Anderson@bristol.ac.uk
Journal of Morphology
|July 13, 2010
Summary
Biomechanical models reveal diverse feeding strategies in ancient armored fish (arthrodires). These analyses highlight varied jaw structures and functions, comparable to modern fish, and emphasize the role of linkage systems in early jaw evolution.
Area of Science:
- Paleontology
- Biomechanics
- Evolutionary Biology
Background:
- Biomechanical models are crucial for understanding functional diversity in fossil species.
- Arthrodire placoderms represent early jawed vertebrates with significant jaw structure diversification.
Purpose of the Study:
- To apply a four-bar linkage model to various arthrodire taxa to analyze feeding kinematics.
- To compare biomechanical variation across arthrodires and explore the evolution of jaw structures.
Main Methods:
- Utilized a computer-based four-bar linkage model for kinematic analysis.
- Calculated metrics such as gape angle, effective mechanical advantage, and kinematic transmission coefficients.
- Mapped linkage system morphology onto a placoderm phylogeny.
Main Results:
- Arthrodire feeding systems exhibit greater diversity and complexity than previously assumed.
- Kinematic profiles are comparable to modern teleost fishes, suggesting potential for suction feeding.
- Identified multiple morphological solutions for achieving rapid jaw kinematics.
Conclusions:
- Four-bar linkage systems played a significant role in the early evolution of jaw structures in vertebrates.
- Functional diversity in arthrodires was achieved through various morphological adaptations.
- Reassessed bite force estimates for Dunkleosteus based on new data.
Related Concept Videos
01:09Cytoskeletal Linker Proteins - Plakins
Plakins are large proteins with binding domains for microtubules, microfilaments, intermediate filaments, and membrane-associated protein complexes at cell junctions. Plakin functions are evolutionarily conserved and are primarily involved in organizing the different components of the cytoskeleton by crosslinking them to each other and connecting them to the cell-matrix and cell adhesion complexes. They are also known to interact with signal transducers, serve as scaffolds for signaling...
01:08Overview of the Skull
The cranium (skull) is the skeletal structure of the head that supports the face and protects the brain. It is subdivided into the facial bones and the brain case, or cranial vault. The facial bones underlie the facial structures, form the nasal cavity, enclose the eyeballs, and support the teeth of the upper and lower jaws.
The cranial vault surrounds and protects the brain and houses the middle and inner ear structures. This cavity is bounded superiorly by the rounded top of the skull, which...
The cranial vault surrounds and protects the brain and houses the middle and inner ear structures. This cavity is bounded superiorly by the rounded top of the skull, which...
01:09Overview of the Axial Skeleton
The skeleton is subdivided into two major divisions—the axial skeleton and the appendicular skeleton. The axial skeleton forms the vertical, central axis of the body. It includes all of the bones of the head, neck, chest, and back. It protects the brain, spinal cord, heart, and lungs. It also serves as the attachment site for muscles that move the head, neck, and back and for muscles that act across the shoulder and hip joints to move their corresponding limbs.
The axial skeleton of the adult...
The axial skeleton of the adult...
01:22Sutures of the Skull
The human skull is composed of several bones that come together to protect the brain and support the structures of the face. The junctions where these bones meet are called sutures.
Sutures are immobile joints between adjacent bones of the skull. The narrow gap between the bones is filled with dense, fibrous connective tissue that unites the bones. The long sutures located between the skull bones are not straight but instead follow irregular, tightly twisting paths. These twisting lines tightly...
Sutures are immobile joints between adjacent bones of the skull. The narrow gap between the bones is filled with dense, fibrous connective tissue that unites the bones. The long sutures located between the skull bones are not straight but instead follow irregular, tightly twisting paths. These twisting lines tightly...
01:27Cranial Bones: Lateral View
The lateral view of the cranium is dominated by temporal, sphenoid, and ethmoid bones.
The temporal bone forms the lower lateral side of the skull. The temporal bone is subdivided into several regions. The flattened upper portion is the squamous portion of the temporal bone. Below this area and projecting anteriorly is the zygomatic process of the temporal bone, which forms the posterior portion of the zygomatic arch. Posteriorly is the mastoid portion of the temporal bone. Projecting...
The temporal bone forms the lower lateral side of the skull. The temporal bone is subdivided into several regions. The flattened upper portion is the squamous portion of the temporal bone. Below this area and projecting anteriorly is the zygomatic process of the temporal bone, which forms the posterior portion of the zygomatic arch. Posteriorly is the mastoid portion of the temporal bone. Projecting...
02:54Evolutionary Relationships through Genome Comparisons
Genome comparison is one of the excellent ways to interpret the evolutionary relationships between organisms. The basic principle of genome comparison is that if two species share a common feature, it is likely encoded by the DNA sequence conserved between both species. The advent of genome sequencing technologies in the late 20th century enabled scientists to understand the concept of conservation of domains between species and helped them to deduce evolutionary relationships across diverse...