Arborization of dewlap motoneurons in the green anole lizard (Anolis carolinensis) is not sexually dimorphic

Male anoles extend a brig ht red throat fan, called a dewlap, du ri ng both courtship and aggressive encounters. Female anoles perform this behavior less often than males and only in aggression towards both sexes. The cartilage, muscle fibers, and motoneuron somata controlling the display are larger in males than females. In the present study, we used the Golgi technique in an effort to characterize more completely the morphology of these dewlap motoneurons, and to investigate whether the dendritic arborization is different between the sexes. In addition to describing the morphology, we report that the length of processes, and numbers of primary processes and branch points are comparable in males and females. This similarity in arborization represents an intriguing contrast to other sexually dimorphic neuromuscular Systems. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.