Skulls_2024W1_Post

Chondrocranium

The part of the skull that forms the braincase and arises from neural crest cells and mesenchyme.

Dermatocranium

A component of the skull composed of dermal bone that forms most of the exterior of the skull.

Splanchnocranium

The part of the skull that arises from the neural crest cells and helps form the branchial arches as well as their derivatives.

Endochondral Bone

Bone that develops from cartilage, typically seen in the chondrocranium during development.

Intramembranous Bone

Type of bone formation that occurs directly from mesenchyme, characteristic of the dermatocranium.

Phylogeny

The study of evolutionary relationships among biological entities—often species, individuals or genes.

Temporal Fenestrae

Openings in the skull that allow more space for jaw muscles, classified into anapsid, synapsid, and diapsid.

Autostyly

A type of jaw suspension where the upper jaw (palatoquadrate) is fused directly to the chondrocranium.

Hyostyly

Jaw suspension in which the upper jaw is not directly attached to the skull, but instead is suspended by ligaments and the hyomandibula.

Secondary Palate

A structure present in some vertebrates that separates the oral and nasal passages, allowing for simultaneous breathing and eating.

Cranial Kinesis

The movement of the skull elements, particularly the upper jaw relative to the braincase, allowing for increased flexibility in feeding.

Paleostyly

The primitive condition of jaw suspension in agnathans where all branchial arches support gills.

Metautostyly

Jaw suspension present in most amphibians and reptiles where the jaws attach via the quadrate bone.

Modified Hyostyly

A complex jaw suspension found in actinopterygians where multiple bones assist in jaw movement, allowing for more kinetic motion.

Prehension

The act of seizing or grasping; commonly associated with how vertebrates capture prey.

Mastication

The process of chewing food, which in vertebrates, is often facilitated by the structural design of the jaws and teeth.

Branchial Arches

Structures that develop in the embryo and contribute to the formation of the splanchnocranium, including the first two arches which form the jaws.

Mandibular Arch

The first branchial arch that gives rise to components of the jaw; composed of palatoquadrate cartilage and Meckel's cartilage.

Hyoid Arch

The second branchial arch that supports the jaw and contributes to the hyoid apparatus in various vertebrate taxa.

Taxon

A group of one or more populations of an organism or organisms that form a unit.

Hypothalamus

A region of the brain important for hormone production and regulation of autonomic functions.

Suction Feeding

A method of feeding involving rapid expansion of the buccal cavity to create negative pressure that draws in prey.

Phylogenetic Trends

Patterns and changes observed in the evolutionary lineage across different taxa.