Evolutionary Biologist and Nature Photographer

Posts tagged “Costa Rica

I’ll have the ‘Cuisses de Grenouille’ please

The family Colubridae is the most diverse family of snakes with almost 2,000 species, though this group is non-monophyletic (that is, in evolutionary terms, the group does not contain all descendants of the most recent common ancestral species).  Thus, this family requires a great deal of work by taxonomists to sort out the natural groups and determine relationships among them.

Leptophis is a genus of colubrid snakes, commonly called parrot snakes.  Parrot snakes are long, slender, bright green snakes found in the tropical forests of Central and South America.

The parrot snake shown in the first two images below, Leptophis ahaetulla (Colubridae), had just found itself a hearty meal. Despite having obviously lost this battle, the frog did not give up the fight so easily, as it kicked and squirmed until the very end. If you look at the expanded body of the snake you can see just how large this frog was – the snake was more than 4 feet in total length.  Notice that the skin stretches as the snake swallows the frog – the blue coloration is the skin beneath the green scales.

(Click the images to see them in full size)

Parrot snake (Leptophis ahaetulla)

Parrot snake (Leptophis ahaetulla) eating a frog, La Selva Biological Station, Costa Rica

Parrot snake (Leptophis ahaetulla)

Parrot snake (Leptophis ahaetulla) eating a frog, La Selva Biological Station, Costa Rica

The next three photos are a second species of parrot snake, Leptophis depressirostris, barely distinguishable from the species shown above except for one scale between the eye and the nostril (just learned this interesting fact today from a friend, Ethan).

In the picture below, this parrot snake is demonstrating its incredible and intimidating defensive display.

Satiny Parrot Snake

Satiny Parrot Snake – Leptophis depressirostris (Colubridae), La Selva Biological Station, Costa Rica

Below you can see the body of a large tick, full of blood, attached under a scale on the snake’s neck.

Satiny Parrot Snake

Satiny Parrot Snake – Leptophis depressirostris (Colubridae), La Selva Biological Station, Costa Rica

Satiny Parrot Snake - Leptophis depressirostris (Colubridae)

Satiny Parrot Snake – Leptophis depressirostris (Colubridae), La Selva Biological Station, Costa Rica

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The green harvestman!

This species appears to be well camouflaged in its natural habitat – high elevation tropical wet forest with an abundance of mosses and ferns at Las Brisas Nature Reserve, Límon province, Costa Rica.  Luckily I snapped some photos of this species before preserving a few individuals in ethanol to examine later in the lab because, unfortunately, the gorgeous color faded quickly!  Upon closer inspection our research team discovered that the harvestman does not produce the green pigment, but rather, the pigment is produced by epizoic cyanobacteria that lives on the dorsal scute of the harvestman.  This is an extraordinary example of the evolution of symbiosis.  Although it is unclear whether this relationship is mutualistic (one would have to determine whether the cyanobacteria is actually benefiting), the green coloration does appear to provide camouflage for this harvestman within the very lush, green habitat in which it was observed.

Prionostemma sp. "verde" - The green harvestman

Prionostemma sp. “verde” – The green harvestman


Part IV: Chemical Defenses of Harvestmen

Longlegs fact #4: Harvestmen have repugnatorial glands that produce compounds used in chemical defense.

These repugnatorial glands are also known as defensive glands, scent glands, stink glands or odoriferous glands.  The repugnatorial glands are a major synapomorphic character of Opiliones.  This means that the glands are a derived character, shared among all Opiliones (and their most recent common ancestor), but not among other arachnid groups (though other arachnids may have different chemical defense mechanisms).  The glands produce chemical compounds that are meant to deter predators.  The chemical compounds produced are very diverse but many are forms of quinones and phenols.  The openings of the glands are on the body near the second pair of legs.  The harvestmen usually release this secretion when threatened or disturbed.

The chemical compounds produced by some species can actually be detected by our own senses.  When I collect harvestmen by hand I will sometimes smell them just out of curiosity (despite the crazy looks I get).  The chemical compounds produced by some species are surprisingly potent!  If I were a natural predator of harvestmen I would think twice about consuming them after getting a whiff of this.  And no, I have not tried tasting them! Yet.

A species of Cosmetidae using its chemical defenses.  The yellow droplet seen on the legs was first produced from the glands on the body and then transferred to the legs. A clear droplet can be seen on the body between legs I and II (on the right side).

Eupoecilaema magnum (Cosmetidae), one of the largest cosmetids, from La Selva Biological Station, Costa Rica.

Another species of the family Cosmetidae. There are over 700 species just in this one family!

 

Although there will be many more interesting stories and facts that I will share about harvestmen in future posts, this post will conclude my series on the introduction to the biology of harvestmen.


Part III: How many species of daddy longlegs?

Longlegs fact #3:

With more than 6,500 species, Opiliones represent the third largest order of Arachnida.  The largest arachnid order is mites/ticks (order Acari) with more than 50,000 described species, followed by spiders (order Araneae) with more than 40,000 species.  For a better frame of reference consider this: there are approximately 5,700 species of mammals in the world while there are more than 350,000 species of beetles in the world.

Almost every time I travel to a new place in Central America to collect harvestmen, new species are collected.  So there’s plenty more work to be done in understanding and describing the diversity of this group.

Below are more photos of harvestmen from Costa Rica.

Meterginus inermipes (Cosmetidae) from Costa Rica

Cynortellana oculata (Cosmetidae) from Costa Rica

Unknown species, likely a new species, of Cosmetidae

Prionostemma sp. (Sclerosomatidae) from Costa Rica


The truth about daddy longlegs

The arachnid order Opiliones has several common names in English including daddy longlegs, grand daddy longlegs and harvestmen.  I have many wonderful things to share with you regarding the natural history of Opiliones so I’m going to post it in a series of about five posts. Here is the first fun fact to whet your appetite.  Keep an eye out for the others very soon!

Longlegs fact #1: Daddy longlegs are NOT spiders.

They are also not insects.  So what are they?  Well, I’m glad you asked.  Daddy longlegs are arachnids belonging to the order Opiliones.  The subclass Arachnida includes spiders, scorpions, mites/ticks, daddy longlegs, and several smaller groups, all of which belong to different orders.  So daddy longlegs are distantly related to spiders, but are actually more closely related to scorpions!

These incredible arachnids are easily overlooked, as they are most active at night and many species are very secretive in their behavior.  Here’s a few examples of species from Costa Rica:

Prionostemma sp. feasting upon what remains of an insect

Cynorta marginalis eating an earthworm as a second individual sneaks up.

Poecilaemula signata (male) with enlarged chelicerae

The orange harvestman, an undescribed species

For more arachnid photos see my Arachnid gallery.


Mushroom Forest

This is one of my personal favorites of all my macro shots.  These tiny mushrooms were such a lucky find.  When I realized how great the shots turned out I wanted to go back and try out some other camera settings.  But by the time I returned the following day all of the mushrooms had been eaten.   Location: Las Brisas Nature Reserve, near Turrialba, Costa Rica, July 2011.

I entered this photo in the “Art of Nature” photo contest at PhoozL.

Photo caption: From an insect’s viewpoint these mushrooms tower above creating a mystical landscape.

Mushroom Forest


Red-Eyed Tree Frog

I love photographing herps!  Especially the Red-Eyed Tree Frog of Central America.  This frog is so photogenic that it is difficult to take a bad picture of these spectacular animals!  These frogs are commonly represented as the face of conservation efforts to save the rainforest.  Many frogs (and other amphibians) are rapidly becoming endangered because of habitat loss as well as the spread of a deadly chytrid fungus called Bd.  See below for links to more information.

I recently submitted this photo to the “Art of Nature” photo contest on PhoozL.com .  Click the first image below and it will take you to the PhoozL gallery for the contest.  Its free to enter, so submit your own photos!

Here are some of my other favorites.  I just never get tired of seeing these amazing frogs!

Here’s some links in case you are interested in learning more!

http://www.savethefrogs.com/

http://www.amphibianark.org/the-crisis/chytrid-fungus/

http://www.amphibians.org/