Morphology and histochemistry of alligator erections

[Jura <pristichampsus@yahoo.com>]

I remember seeing this at SICB this year. It was one of TWO talks on alligator 
wangs. That was the best day of the conference. :)

Jason

http://onlinelibrary.wiley.com/doi/10.1002/ar.21521/abstract

Abstract:

Phalli of male crocodilians transfer sperm to female cloaca during 
sexual intercourse, resulting in internal fertilization. For over a 
century there have been scientific descriptions of crocodilian phallus 
morphologies; however, little work has presented detailed cellular-level
 analyses of these structures. Here we present a histological 
investigation of the complex functional anatomy of the juvenile male 
American alligator phallus, including fibrous and vascular erectile 
structures, a variety of secretory epithelium morphologies, and observed
 immune cells. Using 3D reconstruction software, we show the shape and 
location of vascular erectile tissues within the phallus. Histochemical 
staining detected mucin-rich secretory cells in glandular epithelial 
cells of the phallic shaft and also of the semen-conducting ventral 
sulcus. Lymphoid aggregates, lymphocytes, and epithelial mucin coats 
suggest an active immune system in the phallus defending from both the 
external and intracloacal environments. These results better 
characterize the complexity of the alligator phallus and predict later 
reproductive functions during adulthood. Anat Rec, 2012. © 2011 Wiley 
Periodicals, Inc.


And as a bonus here is a bit that may have relevance to dinosaurs:

Re: Erectile morphology:

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In the functional anatomy of the alligator phallus, muscle associated with the 
cloaca work via the fibrous bodies to cause protrusion of the phallus from the 
cloaca while blood engorges the distal tissues (Ziegler and Olbort, 2007). We 
have shown that the base of the juvenile alligator phalli contains paired 
fibrous bodies which will facilitate erection upon adult sexual activity. This 
mode of crocodilian erection is similar to those described in turtles and 
ostrich (Struthio camelus ). Turtle phalli 
rpus fibrosa) and distally of erectile tissues composed of a sinus defined by 
vascularized connective tissues (corpora spongiosa) (Zug, 1966). Similarly, the 
ostrich phallus presents muscles articulated to a pair of rigid fibrous bodies 
and a vascular body surrounded by a thick outer layer of elastic tissues that 
begins at the middle of the phallus, expands in volume, and extend into the tip 
(Montgomerie
 and Briskie , 2007) .

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