Anole Annals

I probably would have never said this a few years ago, but penises are absolutely fascinating. The phalluses of terrestrial vertebrates exhibit an incredible diversity of shapes and sizes with some possessing elaborate coils, barbs, bony spines, and multiple lobes. Many of us learn about the rapid evolution of sexual characters in our undergraduate classrooms, but until recently I, for one, did not fully appreciate the striking diversity of this organ until immersing myself in the subject area.

Many biologists study the penis under the umbrellas of different research disciplines, but relatively little work has been performed to explain its anatomical diversity. For example, how many times has a penis/phallus evolved among terrestrial vertebrates? This may seem like a trivial question, but the diversity in form, function, and physiology in the adult phallus actually makes this question difficult to address. Historically there has been much conjecture, but little data to support whether the mammalian penis, squamate hemipenes, and phallus of turtles, crocodilians, and basal birds share a single evolutionary origin or are independently derived. But where comparative anatomy has struggled, comparative developmental biology has recently forged ahead. Within the last several months two independent groups have published a total of seven new research articles that help us resolve the question of phallus homology.

I previously wrote about a series of five papers published from the Cohn lab (University of Florida) describing the embryology and gene expression patterns for the developing phallus. Since then this group has published a sixth paper synthesizing this wealth of information, using it to lay out a number of outstanding questions regarding phallus development and evolution. More recently, the Tabin lab (Harvard University) published a paper comparing the cellular-level origins of the genitalia in the laboratory mouse, green anole, house snake, chick, and python. I have had the distinct pleasure of working with both groups as their “anole guy.” Although these studies vary widely in their experimental and comparative breadth, together they have shed much needed light on the evolution of vertebrate genitalia. Here my goal is to discuss how this new wave of research changes what we now know, what we don’t know, and what we think we know regarding the evolution of external genitalia among vertebrates. Take a look at the original research papers for details of the developmental analyses, which represent many technical steps forward in our use of anoles as a laboratory model system and intellectual advancements in our understanding of genital development.

During the gradual transition of life onto land, vertebrates evolved the amniotic egg to facilitate their departure from moist environments.

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Let’s hear it for global warming! Ryan Vince Photography’s Facebook page reported that this brown anole was found in Ontario. Probably still too cold there for the festive anoles to survive, but who know’s in a warming world? Here’s what the FB page had to say: “This little hitchhiker is a Brown Anole that has somehow made its way from Florida all the way down to Ontario, Canada (2000km). I found him in a mulch pile at a local aggregate facility. It seems that he had managed to make it through two sets of wood grinders and now resides in a Vivarium here with me.”

And this isn’t the first report of the festive one getting to Canada. Recently, we had a post reporting brown anoles not only in Canada, but Denmark. Next: the World!!!

In the parched path

I have seen the good lizard

(one drop of crocodile)

meditating.

With his green frock-coat

of an abbot of the devil,

his correct bearing

and his stiff collar,

he has the sad air

of an old professor.

Those faded eyes

of a broken artist,

how they watch the afternoon

in dismay!

 

Is this, my friend,

your twilight constitutional?

Please use your cane,

you are very old, Mr. Lizard,

and the children of the village

may startle you.

What are you seeking in the path,

my near-sighted philosopher,

if the wavering phantasm

of the parched afternoon

has broken the horizon?

 

Are you seeking the blue alms

of the moribund heaven?

A penny of a star?

Or perhaps

you’ve been reading a volume

of Lamartine, and you relish

the plateresque trills

of the birds?

 

(You watch the setting sun,

and your eyes shine,

oh, dragon of the frogs,

with a human radiance.

Ideas, gondolas without oars,

cross the shadowy

waters of your

burnt-out eyes.)

 

Have you come looking

for that lovely lady lizard,

green as the wheatfields

of May,

as the long locks

of sleeping pools,

who scorned you, and then

left you in your field?

Oh, sweet idyll, broken

among the sweet sedges!

But, live! What the devil!

I like you.

The motto “I oppose

the serpent” triumphs

in that grand double chin

of a Christian archbishop.

 

Now the sun has dissolved

in the cup of the mountains,

and the flocks

cloud the roadway.

It is the hour to depart:

leave the dry path

and your meditations.

You will have time

to look at the stars

when the worms are eating you

at their leisure.

 

Go home to your house

by the village, of the crickets!

Good night, my friend

Mr. Lizard!

 

Now the field is empty,

the mountains dim,

the roadway deserted.

Only, now and again,

a cuckoo sings in the darkness

of the poplar trees.

Mike Vallee, a dive instructor on Little Cayman, spends his spare time watching that island’s delightfully long-schnozzed anole. What a great hobby! He says the “anoles are often found in and around the local agave plant. They are the perfect color match and their spiked leaves provide protection from birds and other predators.” He also commented on the photo above, in reference to a previous post on the long snout of this species, that we now know one thing they do with their pointy front end.

Here’s some more lovely pics he took.

 

Father Alejandro Sanchez has done it again! Previously, he posted some wonderful photos of Anolis cuvieri moving around, now he’s caught them in flagrante delicto. Here’s the backstory: “The pics were taken around 10:30 AM. The lizards were about 10 meters above ground. I cannot take credit for the initial sighting. The group of students of UPR-Humacao saw the male jump to the tree where the female was and almost immediately copulation started. In all it lasted about 15 minutes. The separation was very abrupt (possibly caused by the group of people under the tree, taking pictures). At that point the male jumped to another branch and ran down low enough for me to be able to shake it down and capture it. At that time, the male still had his hemipenis everted.”

Capuchin monkeys may look cute, but in reality they’re cold-blooded killers. A recent paper in Herpetology Notes reports on a golden-bellied capuchin (different species than the one pictured above and below) that ate a Polychrus marmoratus, an Anolis ortonii, and an Enyalius catenatus.

Monkey predation on anoles has been documented previously. This paper cites a case of a capuchin eating an A. cupreus, and primatologist Betsy Mitchell recorded one eating an anole–perhaps A. frenatus–in her thesis (which I don’t have in front of me). We also reported on another capuchin species eating a Polychrus in a previous post. A quick google found an undocumented report of rhesus macaques eating A. carolinensis in Florida. Anyone know of any other reports?

And, finally, for your delectation, a video of a capuchin eating an iguana:

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