My morning snack: peach (Prunus persica, Rosaceae)

In this peach you can easily see all three layers of the fruit wall, known collectively as the pericarp, which develop from the ovary wall of the flower. The outermost layer of the pericarp is the exocarp (also called the epicarp), which you know as the soft, fuzzy skin of the peach. The delicious and very juicy layer in from the exocarp is the mesocarp. The hard, woody pit in the middle is the endocarp (often called the stone in drupes). Inside the endocarp is the seed that is white with a brown seed coat.

In this peach you can also see vascular tissue in the flesh and seed coat (look for the horizontal lines in both) and sap leaking from the broken pit (shiny golden droplets at the right top and bottom of the seed).

Hermit crab on the beach.

These little hermit crabs were everywhere! Hermit crabs use the discarded shells of other animals and have to change their shell as they grow. If you search really hard, you can find naked hermits upgrading their shells on the beach. They are in the animal kingdom’s superfamily Paguroidea, but we do not know what family or genus. UPDATE: Marie has identified this little creature as Coenobita compressus in the family Coenobitidae via a comment posted on the blog.

"Lefty" crab (Uca sp.) in the mangrove mud.

We affectionately called these little crabs “lefty” because most of the ones we first saw had their pincher arm on the left (although upon further inspection of the population, many were “righties”). Thanks to a comment from Ana, we now know that they are a species in the genus Uca.

Land crab just outside the research station.

Pacific land crabs (Cardisoma armatum), also known as rainbow crabs and parrot crabs, come to the Pacific shore to reproduce before returning to their primary homes in the forest. They are very brightly colored in their youth, but fade as they age.

Sand dollar on a piece of beach driftwood.

We need even more help with the identity of this little creature. It is a sand dollar that washed up on the shore of Playa Grande and all we know is that it is in the order Clypeasteroida.

Sea snail from the surf sand in Keren's hand.

Sea snails are gastropods that live in saltwater. We saw a few different sea snails in Costa Rica. This one was scooting along just under the sand as the surf was coming in at Playa Grande. We have no idea what species it is, so please help us out.

Butterfly in the forest of Cerro Morro.

We saw many butterflies, but I was only able to photograph a few of them. A beach butterfly appeared earlier in a post by Ely. This one was about halfway up Cerro Morro flying low in the forest and is another species we have yet to identify.

Heron fishing in the mangrove.

This beautiful heron (Ardea species, family Ardeidae) was a common sight during our fieldwork. We greatly enjoyed watching this majestic bird fish and fly.

Male howler monkey making his way through the canopy.

The final animal of this post is one that we heard often and saw a couple of times, the mantled howler (Alouatta palliata, family Alouattinae). These monkeys are found throughout Costa Rica and the males make a sound somewhere between a barking dog and a mad pig to alert others of their presence. It works. You can hear them many kilometers away. This is a monkey you don’t want to aggravate – if you do, they will pee or poo on you! However, howlers are rarely disturbed by people and for the most part tend to ignore them.

Acacia trees: A) yellow Beltian bodies on young leaflet tips; B) inflorescence; C) extrafloral nectaries on petiole, swollen thorn, and ant; D) swollen thorn and ant.

Ant acacias have swollen, hollow thorns in which the ants live. The queen drills a hole in the thorn to gain access. The acacia also provides the ants with two types of food: sugary nectar from extrafloral nectarines at the base of petiole and protein in the form of Beltian bodies that are produced at the tips of new leaflets. In exchange, the ants protect the tree from herbivores by attacking any animal that comes in contact with the plant. They also attack other plants that touch or grow too near their acacia. They trim encroaching branches from neighboring trees and shrubs and cut down any herbaceous plants or seedlings that grow under the acacia. This is one of the most intricate and well-studied mutualistic relationships in nature.

Susan, Gerry, and Ely carrying gear up Cerro el Morro.

Before we left the research station each morning we made sure we had all of our equipment – clippers, pole clippers, newspaper, field presses, GPS, cameras, hand lenses, water and food. Then we walked for a mile or so to get to our collecting destination.

Gerry, Barbara, Ely, and Keren wading through the mangrove.

Everyone kept their eyes open for any plants with flowers or fruit (these are two important characteristics that will allow us to properly identify the plant). But we especially kept our eyes open for snakes (saw a few) and crocs (we never did see any) while we were in the forest and mangrove!

Susan and Ely collecting a Solanaceae on Cerro el Morro.

Barbara, Susan, Ely, and Gerry field pressing plants on the edge of the mangrove.

Collections were quickly placed in our field press between sheets of newspaper to keep them flat until we could get them into a drying press back at the research station.

Ely helping Gerry and Susan close the drying press. Dryer set up in the shower.

When we finished our day of collecting, we returned to the research station and sorted the specimens. Once the specimens were each numbered and labeled, they were stacked with pieces of corrugated cardboard in a large drying press. This press was then placed over a dryer for 48 hours or until the specimens dried.

We are leaving tomorrow but the specimens will stay for another few weeks. Once they are completely dry, they will be shipped to Brooklyn Botanic Garden. We will spend time identifying them and mounting them into herbarium specimens. One specimen will stay at BBG and the others will return to herbaria in Costa Rica. These plants will be used to write the flora of the national park.

The turtle team: Stephen J. Morreale, Jonah Morreale, Sam Friederichs, and Gabriela Blanco.

The research team, led by Gabriela Blanco (Gabi), will locate the female green turtles laying their eggs.

Gabi taking an ultrasound of a female green turtle (photo credit: Sam Friederichs).

Once the female is finished laying her eggs the team will perform an ultrasound to determine whether or not the female has more eggs to lay over the next few weeks (each female can make several trips to the beach to lay eggs over a few week period).

The ultrasound of green turtle eggs in the mama turtle.

If she does not have eggs left to lay, then the team will attach a small cigar-shaped transmitter to the back of her shell. Over the next several months this transmitter will send information about the turtle’s location after it has left Playa Grande. This project will allow the scientists to determine where the Eastern Pacific Green Turtles travel once they have laid their eggs. Gabi’s research has shown that the Eastern Pacific Green Turtles are a genetically distinct population – a population that is under pressure from nesting habitat loss and hunting and is therefore endangered.

Flowering vine in the Apocynaceae.

This Apocynaceae vine was collected previously by Gerry—many of you will notice its resemblance to U.S. native milkweeds and the houseplant Hoya.

Aroid (Araceae) plant (left) and immature fruit (right).

We collected this aroid (Araceae) along a streambed in the hilltop forest. The dried brown structure hanging to the right is the tip of the spathe (bract surrounding the inflorescence) and spadix. The bottom of the spathe remains to protect the developing fruits within.

Poo-eating bug along the trail.

Close to the aroid location, we came upon this rather large (approx. 1.5 inches long) stinkbug relative (shout out to any entomologists out there: Please feel free to correct this identification). As you can see in the picture, it was eating bird scat (poo!).

Liana (Bignoniaceae).

Ely spotted this beautiful purple-flowered plant in the crossvine family (Bignoniaceae) growing in the beachside canopy on Sunday, and we saw it again on Tuesday.

Columnar cactus spines (seen along the beach).

Spiny cacti (Cactaceae) grow along the beach as you walk north from the research station. In addition to the spines, cacti also have more hair-like structures called glochids that not only stab you, but also remain in your skin and cause irritation.

Pelicans flying over the beach.

The walk to the hill involves walking along the disputed park boundary along a barbed-wire fence that weaves back to the beach at several points. On the third beach, we looked up to see a flock of pelicans flying across the little bay—as they passed in front of us they were in a single line. We are heading back to the hill on Thursday, so be on the lookout for more pictures!

Water-dispersed seeds, endocarps (pits), and fruits collected on the beach.

This is not the case in the tropics, where the seeds and fruits of many species wash up on beaches. A quick survey of the beach at Playa Grande turned up this plate of seeds and fruit. The gray seeds are from the previously discussed yellow or gray nicker (Caesalpinia bonduc; see picture in post below), their smooth surfaces a sharp contrast to the plant’s prickly stems, leaves, and fruits. The large smooth brown seed is from sea purse (Dioclea sp.). This plant is a liana (woody vine) that produces beautiful clusters of purple flowers. The large black seed is Mary’s bean (Merremia discoidesperma). This species is also known as crucifixion bean because of the cross-shaped imprint on one side of the seed. The plant that produces it is a liana with yellow flowers. The small brown seeds are from the previously discussed baybean or seabean (Canavalia rosea; see picture in post below).

Germinated seeds of tea mangrove—the left one has germinated more recently than the right. The large side structures are the cotyledons.

The dark brown heart-shaped leathery fruit is from the tea mangrove (Pelliciera rhizophorae). Besides tea mangrove, there are three other kinds of mangrove trees in Costa Rica: black mangrove (Avicennia germinans), gray mangrove (Conocarpus erectus), and red mangroves (Rhizophora mangle, racemosa).

Germinating coconut on the beach. Coconuts are ocean dispersed and are found worldwide in tropical places. For this reason, their geographic origin is unknown.

Coconuts (Cocos nucifera) are, of course, also commonly found washed up on the beaches of Costa Rica.

Tree-trunk driftwood on the beach at Playa Grande.

Driftwood takes on a whole new meaning in the tropics, where one can frequently find very large pieces—some of them entire sections of tree trunks.

While we are here, we are visiting three distinct ecosystems, beach, mangrove, and dry forest, and each holds hundreds of unique things for us to see. We have already seen countless insects and other animal species that have evolved techniques for survival. The diversity of these adaptations are what seem to fascinate all of us as we are out in the field.

Butterfly on the beach.

This brilliant green butterfly has two ways to fool its predators. It is camouflaged to look just like the green leaves of the plants it lands on. Not only does its green color and wing shape mimic a leaf, but its veins look just like the veins on the underside of a leaf. This butterfly also has an eyespot on its wing—another way to trick its predators.

Brilliant green lizard.

With its bright green camouflage it might be hard to find the lizard among all the leaves in this photograph. Many lizards (including this one) can change the color of their skin to blend in with their surroundings. This is done by shifting the melanin in their epidermal cells.

Lizard with a missing tail.

We can only guess what happened to this lizard’s tail, but it was almost certainly dropped on purpose. A defense mechanism used by many lizards is to leave their tail behind when being chased by a predator. The still-moving tail distracts the predator while the lizard makes a quick escape. The tail grows back!