Heads, Jaws, and Muscles: Anatomical, Functional, and Developmental Diversity in Chordate Evolution

-        Janine M. Ziermann: Howard University College of Medicine, Dept. Anatomy,

-        Rui Diogo: Howard University College of Medicine, Dept. Anatomy,

-        Raul E. Diaz Jr.: La Sierra University, Dept. Biology;

Why is this book interesting for a broad audience?

-        Presenting, some extreme cases of heads:

o   feeding adaptations:

  herbivores, carnivore, omnivore (e.g., giraffe, lion, bear; or cow, alligator, rhea)

-        Diversity of not only feeding modes but also sensory adaptations (e.g., large orbits for nocturnal or deep see specimens)

o   recent discoveries show that some developmental mechanisms are conserved from earliest chordate to humans (e.g., cardiopharyngeal field)

-        This book is for everyone that has interest in the diversification, evolution and development of "Heads, Jaws and Muscles".

o   Present idea about emergence of new head at end BUT with Amphioxus and urochordates having already many components of vertebrate head, such as branchiomeric muscles, gills in amphioxus, etc.

1.                Cephalochordates -Daniel Aldea, Stephanie Bertrand & Hector Escriva

UPMC Univ Paris 06, UMR 7232, BIOM, Observatoire Océanologique de Banyuls sur Mer

1. Amphioxus already has a head (branchiomeric) muscles and other head structures (gills etc.)
2. refer to recent studies of muscle development of Yasui et al., of Hector's team on anterior somites, etc.
Urochordates and their importance for understanding the evolution of the vertebrate head and head muscles  - Rui Diogo; Howard University College of Medicine
1. Urochordates closest relatives to vertebrates
2. What do they teach us about evolution and development in vertebrates? cardiopharyngeal field, etc.
Early vertebrate and gnathostome fossils, and the emergence of jaws: You three, any order of names is ok for us Zerina Johanson; Dept. Earth Sciences, Natural History Museum London, Kate Trinajstic; Dept. Environment and Agriculture, Curtin University, Bentley, Western Australia; Per E. Ahlberg; Department of Organismal Biology, Uppsala University
1. What are the main "innovations" towards vertebrates, and then towards gnathostomes?
2. Summary of fossils, etc.
3. Where did the jaw come from? Fossils and associated muscles, etc.Transitions to vertebrates, including fossils? -
1. Cyclostomes - Janine Ziermann; Howard University College of Medicine, Dept. Anatomy)
1. Ziermann & Diogo's suggested ideas to head/neck muscle evolution in cyclostomes and compared to gnathostomes inferred plesiomorphic muscle repertoire
2. Miyashita's idea about derived similarity of mandibular and other branchial arches
2. Chondrichthyans - Peter Johnston; Department of Anatomy with Radiology, University of Auckland & Catherine Boisvert; Australian Regenerative Medicine Institute (ARMI), EMBL Monash University
1. What makes them so special?
3. Actinopterygians - Allesia Huby & Eric Parmentier; Laboratoire Morphologie Fonctionnelle et Evolutive Institut de Chimie
1. Actinopterygians are the most diverse vertebrates, diverse - some with highly specialized heads and jaws and associated muscles
4. Sarcopterygians - Alice Clement; Flinders University, Biological Sciences
1. Adaptations that come in handy for water-land-transition? Focus on head/neck and head/neck muscles.
2. Include transition to tetrapods
Amphibians - Janine Ziermann; Howard University College of Medicine, Dept. Anatomy
1. Present diversity of head / neck structures as adaptation to feeding types, size, and/or other factors
2. First on land - "challenges" with new environment (holding head above ground - neck; feeding - jaw musculature")
3. Specializations: biphasic lifestyle vs. direct development; burrowing (Gymniophiona) vs. diversity in salamander and frogs
Chelonians - Ingmar Werneburg + Gabriel S. Ferreira; Senckenberg Center for Human Evolution and Palaeoenvironment (HEP) at Eberhard Karls Universität
1. Present diversity of head / neck structures as adaptation to feeding types, size, and/or other factors
2. How to turtles contribute to the understanding of head / head muscle development and evolution?
Lepidosaurians (Squamata and Rhynchocephalia) - Raul E. Diaz Jr; La Sierra University, Dept. Biology;
1. Present diversity of head / neck structures as adaptation to feeding types, size, and/or other factors
3. Archosaurs (Crocodylians and Aves, Dinosaurs) - Arkhat Abzhanov; Natural History Museum, Cromwell Road, London
1. Present diversity of head / neck structures as adaptation to feeding types, size, and/or other factors
Include dinosaurs', particularly comparing their heads/jaws with crocodilians and birds, and including head/jaw muscles if possible
4. Mammals, incl. Primates and Humans - Rui Diogo; Howard University College of Medicine, Dept. Anatomy
1. Major innovations related to transition to mammals - licking, suckling, closure of post-orbital foramina due to growth of sphenoid bone - resulting changes in musculature?
General development of mammalian muscles, based on mice
2. Include human birth defects of the head

 

Conclusions/summary/outlook: Ziermann, Diogo, Diaz Conclusion

-        Summary

-        Major open questions that are currently under investigation

-        Where to go from here: Outlook