Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Sutures of the Skull01:22

Sutures of the Skull

13.7K
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...
13.7K
Cranial Bones: Lateral View01:27

Cranial Bones: Lateral View

7.6K
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...
7.6K
Types of Selection01:46

Types of Selection

45.6K
Natural selection influences the frequencies of particular alleles and phenotypes within populations in several different ways. Primarily, natural selection can be directional, stabilizing, or disruptive. Directional selection favors one extreme trait and shifts the population towards that phenotype while selecting against individuals displaying alternate traits. Stabilizing selection favors an intermediate trait with a narrow range of variation. Deviation from the optimal phenotype towards an...
45.6K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Special issue: The evolution of joints in vertebrates.

Journal of anatomy·2026
Same author

The distinct synsacrum of knob-tailed geckos (Gekkota: Carphodactylidae: Nephrurus).

Anatomical record (Hoboken, N.J. : 2007)·2026
Same author

Evidence for high-frequency hearing in a Permian stem reptile.

Nature communications·2025
Same author

When islands collide: Divergence predicts outcomes of secondary contact during the fusion of Sulawesi's paleo-archipelago.

Proceedings of the National Academy of Sciences of the United States of America·2025
Same author

Taxonomic status of <i>Coryphophylax maximiliani</i> Fitzinger in: Steindachner, 1867 with notes on <i>Coryphophylax subcristatus</i> (Blyth, "1860" 1861).

PeerJ·2025
Same author

Ecomorphology of Anurans: The Challenge of Ecological Categories and Locomotor Modes.

Journal of experimental zoology. Part B, Molecular and developmental evolution·2025

Related Experiment Video

Updated: Feb 28, 2026

Systematic Assessment of Mammalian Skull Specimens for Dental and Temporomandibular Joint Pathology
07:26

Systematic Assessment of Mammalian Skull Specimens for Dental and Temporomandibular Joint Pathology

Published on: August 22, 2022

2.0K

How common are cranial sesamoids among squamates?

Ricardo Montero1, Juan D Daza2, Aaron M Bauer3

  • 1Cátedra Vertebrados, Facultad de Ciencias Naturales, Universidad Nacional de Tucumán; Instituto de Herpetología, Fundación Miguel Lillo, Tucumán, Argentina.

Journal of Morphology
|June 22, 2017
PubMed
Summary

Cranial sesamoids, small bones within tendons, are newly identified in several lizard species. This discovery suggests these unique skeletal elements are more common in squamates than previously understood.

Keywords:
basicranial sesamoidelement Xjointsquadrate sesamoid

More Related Videos

Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs
04:28

Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs

Published on: March 31, 2023

2.7K
Midface Hypoplasia and Cranial Base Morphology in Syndromic Craniosynostosis: A Comparative Analysis Study Using a Predictive Regression Model
08:03

Midface Hypoplasia and Cranial Base Morphology in Syndromic Craniosynostosis: A Comparative Analysis Study Using a Predictive Regression Model

Published on: November 4, 2025

313

Related Experiment Videos

Last Updated: Feb 28, 2026

Systematic Assessment of Mammalian Skull Specimens for Dental and Temporomandibular Joint Pathology
07:26

Systematic Assessment of Mammalian Skull Specimens for Dental and Temporomandibular Joint Pathology

Published on: August 22, 2022

2.0K
Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs
04:28

Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs

Published on: March 31, 2023

2.7K
Midface Hypoplasia and Cranial Base Morphology in Syndromic Craniosynostosis: A Comparative Analysis Study Using a Predictive Regression Model
08:03

Midface Hypoplasia and Cranial Base Morphology in Syndromic Craniosynostosis: A Comparative Analysis Study Using a Predictive Regression Model

Published on: November 4, 2025

313

Area of Science:

  • Vertebrate Anatomy
  • Paleontology
  • Evolutionary Biology

Background:

  • Sesamoids are intratendinous bones with genetic and epigenetic origins.
  • Cranial sesamoids are rare in tetrapods, previously documented only in birds, crocodiles, and turtles.
  • Their presence and function in squamates remain largely unexplored.

Purpose of the Study:

  • To investigate the presence and diversity of cranial sesamoids in squamate reptiles.
  • To characterize the location and potential function of newly identified sesamoids.
  • To assess the evolutionary significance of cranial sesamoids in squamates.

Main Methods:

  • Histological analysis of tissue sections.
  • Dissections of preserved specimens.
  • Examination of dry skeletons and cleared/stained specimens.
  • Computed tomography (CT) scans.

Main Results:

  • Two types of cranial sesamoids were identified in seven examined squamate species.
  • A sesamoid attached to the quadrate's cephalic condyle was found in Ophiodes intermedius.
  • A basicranial sesamoid, reinterpreted from 'element X', was confirmed in multiple squamate families, including Gymnophthalmidae, Gekkonidae, and Pygopodidae.

Conclusions:

  • Cranial sesamoids appear to be a widespread feature in squamates.
  • The basicranial sesamoid likely functions to resist forces during head flexion.
  • This suggests cranial sesamoids may have been present since the early evolution of squamates.