Author

Catherine May
http://kusumi.lab.asu.edu/catherine-may/     Email

Organisms: Vertebrates
Embryonic Patterning: Segmentation; Compartments/Boundaries
Mesoderm-derived: Cardiovascular System; Somites; Limb Formation
Organism: Lizard
Stage of Development: Embryo

Object Description

This is a Stage 3 anole lizard (Anolis carolinensis) embryo. The optic cup (oc) and lens are well defined. Pigment is present at the posterior portion of the retina. The otic vesicle (ov), or future ear, is visible along the dorsal portion of the embryo. Dorsal/rostral to the otic vesicle is the future hindbrain (hb) and rhombencephalon. Ventral to the otic vesicle is the maxillary arch (ma), the mandibulary arch (md) and the branchial arches 2-4 (ba2-4). The maxillomandibular region will become the upper and lower jaw. The mandibulary arch and branchial arch are in the process of fusing. The heart (hr) will develop 3 chambers.

The telencephalon (te), diencephalon (di), and mesencephalon (me) are present but vaguely defined. Later, a telencephalon and diencephalon constriction will further separate these regions. The mesencephalon has increased in size, but is empty. Progenitor cells in the tailbud (tb) will enter the pre-somitic mesoderm (psm). Signaling networks and gradients will result in the formation of somites. There are 30-40 somites (s) that lie along the AP axis, which will become future vertebrae. The forelimb (fl) and hindlimb (hl) are elongating.

References

Aulehla, A., Wehrle, C., Brand-Saberi, B., Kemler, R., Gossler, A., Kanzler, B., Herrmann, G. Wnt3a Plays a Major Role in the Segmentation Clock Controlling Somitogenesis. Developmental Cell, 2003, 4:395-406.

Eckalbar, W.L., Lasku, E., Infante, C.R., Elsey, R.M., Markov, G.J., Allen, A.N.,  Corneveaux, J.J., Losos, J.B., DeNardo, D.F., Huentelman, M.J., Wilson-Rawls, J., Rawls, A., Kusumi, K. Somitogenesis in the anole lizard and alligator reveals evolutionary convergence and divergence in the amniote segmentation clock. Developmental Biology, 2012, 363:308-319.

Gilbert, S.F. Developmental Biology. 9^th Edition. Sunderland, MA, Sinauer Associates, 2010.

Sanger, T.J., Losos, J.B., Gibson-Brown, J.J. A developmental staging series for the lizard genus Anolis: A new system for the integration of evolution, development, and ecology. Journal of Morphology, 2008, 269:129-137.

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