November 23, 2014
Not many birders get to see King Vultures, SARCORAMPHUS PAPA, because they're so rare, and disappearing along with the heavy tropical forests they need. They're native from southern Mexico to Northern Argentina, though in most of that area they've disappeared. With larger wingspreads than Turkey Vultures -- up to 76inches (82cm) -- and stockier, plus, being mostly white instead of the usual "vulture black," they're impressive birds. When serious birders sign up for a tour with my host Diego Nuñez, often the top bird on their dream list is the King Vulture.
That was the case the other day when some folks from the US, Diego, and I were out canvasing the transition zone between the marshes and savanna. Diego's incredibly sharp eyes picked up two tiny dots circling over the mangroves, slammed on the brakes and declared them to be King Vultures. Even with binoculars at that distance I couldn't distinguish them from similarly black-and-white White Pelicans, but the dots were drifting our way, so before long we could all see that they were King Vultures. A few minutes later yet a third turned up, this time circling right above so close that even with my little camera I could get the picture shown at http://www.backyardnature.net/n/14/141123kv.jpg.
Diego had spotted King Vultures in the same place before and at the same time of year, so we're hoping that the birds are thinking of settling here. If that happens, birders from all over will flock here to see them. Diego and the US birders had camera lenses over a foot long, enabling them to capture's the bird's rainbow head colors, the white eyes, bright orange eye circles, yellow wattle, red bill, on mostly dark gray skin, all so colorful it looked made-up. It was a birdwatcher's dream.
King Vultures eat anything from cattle carcasses to beached fish and dead lizards, and they've been reported to kill and eat injured animals, newborn calves and small lizards. They're known to find their food with vision, but it's debated whether they can locate carrion by smell the way Turkey Vultures can.
On a little one-lane, dirt road through the savanna south of town two bobwhites ran along in front of us looking as if they'd rather do anything than take flight. We stopped, one turned sideways to give us the eye, and I snapped the picture at http://www.backyardnature.net/n/14/141123bw.jpg.
If you have Northern Bobwhites in your area, they probably look different from this one, having white throats instead of black, and underparts not nearly as "black-edged scaly looking" as this one. However, if you're familiar with the Northern Bobwhite's remarkable regional variations over its large distribution area -- including completely black-headed ones with dark chestnut underparts in southern Mexico on the Pacific Slope -- then you might think that our Yucatan birds are just an extreme variation of the Northern Bobwhite. In fact, some experts think that that might be the case. However, most field guides do separate our Yucatan birds from the Northern species, referring to them as Yucatan Bobwhites, COLINUS NIGROGULARIS.
I love being down in the savannas in the mornings when the bobwhites are calling, their "bob-WHITE!" calls as sincere and clear sounding as I remember them back in the Kentucky countryside long ago. It's especially gratifying to hear them here because at my previous bases in Mississippi and Texas they've pretty much disappeared, presumably the victims of invasive fire ants. A study by CB Dabbert and JM Mueller available on a Texas A&M website reports that in their study in Texas, 38% of all mortality to bobwhite chicks up to 21 days of age was attributable to fire-ant stings at hatching. Though we have stinging ants here, I don't think they're fire ants, and they certainly aren't as numerous as in the US's fire-ant infested areas.
The Yucatan Bobwhite's distribution is an odd one. It occurs in brushy woodlands, overgrown fields and beach scrub throughout the northern and central Yucatan Peninsula, then there's a disjunct population in Belize, and yet another disjunct group in Caribbean Honduras and Nicaragua.
North America is home to several grebe species, some fairly commonly seen, but in the US only in southern Texas can you see the one shown in a shallow freshwater pond just south of Río Lagartos at http://www.backyardnature.net/n/14/141123gb.jpg.
That's the Least Grebe, TACHYBAPTUS DOMINICUS, the smallest grebe in all the Americas. The well known little Pied-billed Grebe occurring across North America is nine inches long (23cm) but the Least Grebe is only 6½ inches (17cm). Such striking, amber-colored eyes is fairly commonly occur among the grebes, though the Pied-billed Grebe's are dark. From southern Texas the Least Grebe is distributed throughout the Americas south to Argentina.
The Least Grebe's genus name, Tachybaptus, breaks down to the Greek takhus, meaning fast, and baptos, meaning diving, or sinking under, and that's exactly what our grebe did a split second after the above picture was taken. I read that when feeding, on the average during its dives, it spends 12.5 seconds submerged, with surface pauses ranging from 224 seconds. Least Grebes mainly eat small fish, crustaceans, frogs and aquatic insects.
Much of the Ría Lagartos estuary that mostly surrounds the town of Río Lagartos is only knee deep or less at low tide. In a shallow area where the boat motor had to be tilted up so as to not cut into the mud, and where seaweed grew in patches with open mud between them, Diego, a son of my host Diego Nuñez, pointed out to me a small blob I'd never have noticed without his help. You can see the patch of estuary shallows with the well camouflaged object at http://www.backyardnature.net/n/14/141123jf.jpg.
The object was a jellyfish, but one unlike any I'd seen. The entire area was populated with them, some thumbnail-size but others 9cm or more across (3½ inches). You can see a couple in water-filled containers at http://www.backyardnature.net/n/14/141123jg.jpg.
In terms of how jellyfish normally present themselves, the larger one at the left is upside-down, the way it normally is on the estuary's mud floor. The one at the right is right-side-up displaying its "umbrella," or "bell," but after floating that way a few minutes slowly it turned itself so that its umbrella lay against the floor. Notice that the umbrella of the one on the right is depressed like the center of a suction cup. As the jellyfish lies on the estuary floor gently pulsating, the depression helps it stay on the bottom by providing something of a suction effect.
That day as we floated in the shallows looking for jellyfish we were lucky enough to have Willie Cruz along, a genuine biologist, who saved me the trouble of identifying our jellyfish by telling me outright that it was CASSIOPEA XAMACHANA, usually referred to simply as the Upside-down Jellyfish.
We think of jellyfish as floating in water or at the water's surface, dangling slender tentacles from their bodies. In the Upside-down Jellyfish's case the tentacles consist of eight thick, elaborately branched "oral arms," which are projected upwards from the jellyfish on the left in the above picture. The arms, as with other jellyfishes, are covered with "nematocysts," which are cell-like structures from which stinging hairs are shot when the nematocyst is stimulated. These stinging hairs are used in self defense and for immobilizing tiny prey. A close-up of an oral arm's nematocyst-covered branches is at http://www.backyardnature.net/n/14/141123ji.jpg.
In the first picture you may have noticed a few dark, club-shaped, flattened items arising from the oral arms. These are "vesicular appendages," of which the number, size, and color vary with sex and age. On the Internet pictures can be found of large ones bearing dozens of vesicular appendages. Amazingly, the function of vesicular appendages isn't well understood. You can see a close-up of one, looking like a parasitic leech, at http://www.backyardnature.net/n/14/141123jk.jpg.
Normal jellyfish use their tentacles to conduct prey into their mouths, which open into a stomach-like "gastrovascular cavity" inside the organism. The Upside-down Jellyfish goes a step further: Curing the course of evolution its central mouth has closed, but many "secondary mouths" have arisen at the ends of branches of the eight oral arms.
Upside-down Jellyfish don't entirely rely on prey for their food, for the organism's body is filled with thousands of "zooxanthellae," which are microscopic, yellow-green or yellowbrown algae who live symbiotically in the jellyfish's cytoplasm, providing the jellyfish with oxygen and sugars the alga photosynthesizes, in the process using some of the jellyfish's waste products, all in exchange for a cozy place to live.
Jellyfish life cycles are complex. The item in our photos is the medusa, or adult stage. Cassiopea xamachana is "dioecious," which means that the medusas come in male and female flavors. Beyond that, things get too complex to go into detail about here. The life cycle is described in detail at http://animaldiversity.ummz.umich.edu/accounts/Cassiopea_xamachana/.
BEACHCOMBED WORM TUBES
Washed up on the white sand of the beach on the ocean side of the barrier island across the estuary from Río Lagartos, the interesting item turned up seen at http://www.backyardnature.net/n/14/141123wt.jpg.
Looking like a mass of fossilized macaroni, it was heavy and rock hard, like a chunk of coral, but it didn't look like coral. A close-up showing an important identification feature is shown at http://www.backyardnature.net/n/14/141123wu.jpg.
In the center of the right half of the picture, notice the little "chimney" with a thin, white interior wall. It's like a bent, white, plastic straw with white sand cemented to its exterior. Coral consists of communities of tiny animals cemented together, but here you see nothing of the chambers in which a coral's animals might live. When you think about it, about the only thing that might live in such curvy, long, strawlike structures is a worm, or wormlike creature who excretes a smooth, white, thin tube to which sand becomes attached.
I'm guessing that these are tubes formed by polychaete worms. A list of invertebrates identified by various experts working in this area lists several polychaete worm species. The list is available on a web page of my host, Diego Nuñez, at http://www.riolagartosnaturetours.com/Pages/marineinvertebrates.aspx.
I learned about polychaete worms while at Mayan Beach Garden Resort north of Mahahual on the Caribbean coast of Quintana Roo. There, attached to clam shells found on the beach, I noticed calcified and highly detailed squiggles looking like eel skeletons. You can see what that looked like at http://www.backyardnature.net/yucatan/shell-tb.htm.
Those squiggly polychaete worm tubes are very different from the much larger, sand-walled items in our current photo, but the world of polychaete worms is a big one, with over 10,000 known species, and among those species the variety of living styles is as diverse as can be imagined. You might enjoy looking over Wikipedia's illustrated Polychaete page at http://en.wikipedia.org/wiki/Polychaete.
Polychaetes are worms belonging to the Segmented Worm Phylum Annellida, so they're annelids, like earthworms. They're in the class Polychaeta, of which about 98% live in saltwater.
Most tube-dwelling polychaetes are members of the Subclass Sedentaria, and of that group I read that tubes may be built of unadorned mud, sand, or parchment, which often are decorated with sand, shell fragments, algae, tiny animals called hydroids, or of hardened calcium carbonate. A thin tube of hardened calcium carbonate decorated with sand is exactly what we appear to have.
I can't find pictures on the Internet looking like our find, but in this article I've used enough keywords -- polychaete, Sedentaria, tube-dwelling -- that web-browsing experts will eventually find this page, and maybe one of them will tell us exactly what we have, and maybe they'll be happy to know that what's shown in our photos has been spotted in the Ría Lagartos Biosphere Reserve.
South of Río Lagartos, in the transition zone between marshes and the modestly higher "upland" area (ten feet or so), thin soil atop outcropping limestone hosts lots of interesting plants. Usually the plants are interesting because they're endemics found only in this area, and/or display remarkable adaptations to deal with the thin, highly calcareous soil and the long dry seasons when such thin soil must become little more than dust. Often such plants are succulents, the gummy material inside them storing water for the dry season. One such plant, with thick, succulent stems and standing about head high, is shown at http://www.backyardnature.net/n/14/141123pm.jpg.
A close-up of foot-long leaves clustered at a stem's tip, with an inflorescence's first, wonderfully fragrant flower blossoming, is at http://www.backyardnature.net/n/14/141123pn.jpg.
We've seen this plant before, near Chichén Itzá, where in deeper soil it grew into a 25 feet tall tree (8 m) and, in September in the rainy season, bore fruit. You can see that tree at http://www.backyardnature.net/n/10/100919pl.jpg.
This is one of two native Yucatán Frangipani or Plumeria species, PLUMERIA OBTUSA. Frangipanis produce those beautiful, fragrant flowers that in Hawaii are strung onto the necklaces called leis. Because of that, most North Americans think of Frangipanis as Hawaiian plants, but in fact they're native of the Yucatán. Both species are planted in tropical and warm climates worldwide, because of their exquisite flowers and ease of cultivation. The other species, Plumeria rubra, is native from central Mexico south through Central America to Colombia and Venezuela in South America, but our Plumeria obtusa is more of a native of Caribbean islands, plus southern Florida, southern Mexico, Belize and Guatemala.
Nowadays a fairly common bush or small tree is issuing white flowers with spectacular corollas over two inches long (6cm), as shown at http://www.backyardnature.net/n/14/141123ex.jpg.
Noticing that this plant's leaves occur two per stem node and that the flower's sepals and corolla arise above the ovary, not below it (it's "inferior") a good guess is that the plant belongs to the big, mostly tropical Coffee or Madder Family, the Rubiaceae. The way to confirm that is to look for conspicuous stipules or stipular lines connecting the tops of leaf petioles across the stems. You can see one of this plant's triangular stipules -- the left leaf has fallen off -- at http://www.backyardnature.net/n/14/141123ey.jpg.
So, this member of the Coffee Family is EXOSTEMA CARIBAEUM, often called Princewood. It occurs on islands throughout the Caribbean, including the Florida Keys, and from the northwestern coast of South America north to central and northeastern Mexico. It grows in arid coastal thickets, low rises in marshy areas (hummocks) and woodlands on limestone, so this area is about perfect for it.
On Caribbean islands, bark extracts of Princewood traditionally have been used medicinally to treat malaria, anemia, diarrhea, hemorrhoids, stomach aches, ringworm, to increase appetite, regulate low blood pressure, and also as a general "strengthening tea." In some places the bark extracts enjoy fame as an intensifier of drunkenness when mixed with alcohol.
In those occasional spots where very thin soil lies atop limestone and the forest has been cleared or maybe never got established in such thin soil, around here you're likely to find a head-high shrub with many slender, succulent, mostly leafless stems of a kind you expect in deserts, not areas like ours mainly occupied with broadleaf shrubs and low trees. You can see my photographer friend Jim Legault providing scale next to one at http://www.backyardnature.net/n/14/141123eu.jpg.
Nowadays at the tips of those leathery, white-latex filled stems you find clusters of very distinctive flowering structures, each shaped something like an apple turnover. Each structure is equipped with two blackish, eye-like glands exuding an ant-attracting substance, some ants nearly always found supping there, as shown at http://www.backyardnature.net/n/14/141123ev.jpg.
A close-up of a flowering structure is shown at http://www.backyardnature.net/n/14/141123ew.jpg.
Notice that the turnover-looking structure at the top of the picture has some pale items emerging from it directed toward the picture's top, right corner. Those are pollen-releasing anthers. The greenish, egg-shaped item in the picture's center, dangling on a maroon-colored stem emerging from the turnover's bottom, is an ovary. Two long, slender, red styles point downward from the ovary.
In other words, what we've been calling a turnover is actually a "cyathium," inside which reside a cluster of close-packed male flowers, each consisting of a single stamen. The ovary dangling on its maroon stem is the female flower. All this strange floral anatomy constitutes the classic basic configuration of that large group of flowering plants known as the spurges, genus Euphorbia, in the Spurge or Poinsettia Family, the Euphorbiaceae. We've profiled numerous euphorbias in this Newsletter, but this is the first species in which the cyathium was shaped like an apple turnover.
The big genus Euphorbia embraces about 2000 species and it's hard to think of a genus with more variability in its appearance -- from leafy trees to low, spiny, cactus-like forms -- but they all produce their much-reduced flowers in cyathia. However, only a small number of euphorbias produce cyathia shaped like apple turnovers. For many years those with such cyathia were set aside in the genus Pedilanthus, but now genetic sequencing reveals that really they're just normal euphorbias with a novel adaptation. Apparently to their hummingbird pollinators the reddish cyathia are shaped not like apple turnovers but hummingbird heads, with the black, ant-attracting glands looking like hummingbird eyes.
Our Río Lagartos plants are EUPHORBIA PERSONATA. Really there's no common English name for them, but another better-known species with similarly shaped cyathia is known as a Slipper Spurge, so this one might as well share that name. Our Río Lagartos species is distributed from here in the Yucatán south to Costa Rica. However, it inhabits only clearings on limestone outcrops, mostly near the coast, so its occurrence is very spotty and limited. Here it's commonly encountered, but during my two years in the Chichén Itzá area about an hour south and inland from here I never saw it.
When I first saw how common the plant is here, I thought it might be a weed, but now it's clear that it's yet another unusual species the Ría Lagartos Biosphere Reserve can be proud to be home to.
At the edge of a dense, weedy patch of scrubby woods in the savanna south of Río Lagartos, a tree about the size of an elephant bore long, slender, flattish, legume-type fruits as shown at http://www.backyardnature.net/n/14/141123ca.jpg.
The leaves were pinnately compound, mostly with five or seven leaflets, rather like leaves of the North's ash trees, as you can see at http://www.backyardnature.net/n/14/141123cb.jpg.
However, the leaves' leaflets were too thick and leathery to be those of a northern ash. Below, they were densely covered with short, soft hairs causing the lower surfaces to be much paler than the glossy upper ones. And the leaflets' stems, or petiolules, were cylindrical in cross section, not somewhat flattish, as often is the case. You can see all this at http://www.backyardnature.net/n/14/141123cc.jpg.
With such a legume-type fruit, and pinnately compound leaves, what family could the little tree belong to other than the enormous Bean Family, the Fabaceae? Moreover, in this part of the world we have so many small trees and shrubs belonging to the Bean Family genus Senna that by now I can recognize the genus, even if I've not encountered that particular species before, and even without seeing the tree's distinctive flowers, as was the case here. This was classic Senna.
It was SENNA ATOMARIA, in English sometimes called the Yellow Candlewood, or simply Senna Tree. Several tree species are known as candlewoods and several Senna species are trees, so these names aren't the best. Fact is, the species just hasn't registered enough in English speaking minds for a good English name to have become attached to it.
And that's a shame, because this is a fine little tree, a human-friendly one that when adorned with its brightly yellow flowers should be very pretty. In tropical lands, because it's such a useful tree, the locals have come up with many names in Creole, Spanish, French and other languages. Two of the most common Spanish ones are Palo de Burro and Palo de Chivo, translatable into English as Burro Tree and Goat Tree, testifying to the interest hungry burros and goats show in them.
Senna atomaria occurs throughout the Caribbean, in Mexico, here and there in Central America and northern South America, plus it's been introduced in various tropical countries, especially in Africa and India. Its natural habitat is hot, dry, low elevations in spotty forest patches, especially in coastal thorn-scrub and often in association with cacti.
Besides serving as fodder for various livestock, it's a fast grower producing serviceable firewood, and while growing contributes to erosion control, not only with its roots holding soil in place but also with its leathery leaves that on the ground below it form a protective covering for soil.
When crushed, the leaves produce a strong smell suggesting medicinal benefits, and in fact in various cultures Senna atomaria leaves are crushed and massaged into the skin to deal with itch and insect bites.
SAK IITSA' = "FALSE SEAGRAPE"
Along weedy roadsides out in the savannas south of Río Lagartos a common woody shrub or small tree with large, cow-hoof-shaped leaves nowadays is topped with hand-size panicles of white flowers and maturing fruits, as shown at http://www.backyardnature.net/n/14/141123nm.jpg.
With the rainy season ending and the main growing season therefore coming to a close, the big leaves of most plants of this species are just as bug-eaten, fungusy and curled up as the ones shown in the picture. The moment you see this plant you're reminded of Seagrapes, those woody shrubs with similarly large, rounded leaves, and flowers and fruits at the tips of branches, mostly occurring along sandy coastlines. The small flowers have calyxes with white sepals enlarged to look like white corolla lobes, and that's also similar to Seagrape flowers, as you can see at http://www.backyardnature.net/n/14/141123nn.jpg.
However, Seagrape bushes produce succulent, grape-like fruits that are good to eat, while the maturing flowers on this bush indicate that the resulting fruit will have papery "wings" much like the North's weedy Dock plants, genus Rumex, which are members of the Buckwheat or Smartweed Family, the Polygonaceae. Some developing, Dock-like "winged fruits" are shown at http://www.backyardnature.net/n/14/141123no.jpg.
Well, this peculiar combination of features seeming like a mixture between two such outwardly dissimilar plants as Seagrapes and Dock is interesting, because Seagrape also belongs to Dock's Buckwheat Family. So, here we have a member of the Buckwheat Family combining features in a way unlike anything we've seen before.
This is NEOMILLSPAUGHIA EMARGINATA, apparently with no English name, not even an editor's made-up one. The Maya are reported as calling it Sak iitsa' . "False Seagrape" seems like a useful name, so that's what I'll begin calling it, at least in my mind, but always enclosed in quotation marks, to signify that it's a made-up.
We can say, then, that "False Seagrape," is endemic to the Yucatan Peninsula Biotic Province, which embraces the Yucatan Peninsula and northern lowland Guatemala. Among the local Maya it's recognized as a fine nectar producer for their bees, and as a wood source for charcoal production.
THE AQUATIC HORNWORT
In a partially shaded, small, shallow pond in a generally marshy area along the road between Río Lagartos and San Felipi just to our west, knee deep water was about as thickly populated with a feathery, submerged aquatic plant as it could be. You can see some strands of the plant draped on my hand at http://www.backyardnature.net/n/14/141123ce.jpg.
Up close, the leaves showed themselves as twice divided into threadlike filaments, as shown at http://www.backyardnature.net/n/14/141123cf.jpg.
Several widely distributed aquatic plants look more or less like this so at first I felt sure I'd never be able to identify it with certainty. However, then I noticed that some of the submerged stems bore tiny, bright-red fruits in the axils of their leaves. You can see one emerging from its five-lobed calyx at http://www.backyardnature.net/n/14/141123cg.jpg.
Now I could recognize the plant as a kind of usually-overlooked hornwort, genus Ceratophyllum, which back in my student days I'd been thrilled to find populating shallow waters in swamps back in Kentucky -- those swamps now converted to soybean fields. In the world of flowering plants, the angiosperms, the Hornwort Family is distinguished by its species lacking roots, cuticle, stomata and woody or fibrous tissue. The flowers are also reduced and specialized for pollination under water.
Even today it's hard to figure out where hornworts belong on the Phylogenetic Tree of Life. Recent research suggests that the family is so ancient that it branched off at about the same time the ancestors to all monocots and dicots arose. Thus hornworts are best thought of as neither monocots nor dicots, but rather their own thing, and that in itself is something to think about when you're standing there with wet, fruiting hornworts dangling from your fingers.
Anyway, having fruits to work with -- which are somewhat unusual among hornworts in that they lack spines and are so brightly red -- our Río Lagartos plants worked out to the Tropical Hornwort or Soft Hornwort, CERATOPHYLLUM SUBMERSUM. That species occurs in habitats exactly like the little roadside pond on the way to San Felipe, basically worldwide.
But, there's such debate and confusion among experts that any hornwort identification is bound to be contested by someone. Our Tropical Hornwort is one of two well-defined cosmopolitan species, the other being Ceratophyllum demersum, which is more likely to be found in temperate zones. Both species are listed for the Ría Lagartos Biosphere Reserve. More than 30 hornwort species have been described and defined mainly on the basis of fruit-spine number and position, but, according to a hornwort expert, VH Heywood, most are probably no more than variants of those two common species.
Still, our plants fairly well match features regarded to be those of the Tropical Hornwort, and that's how I'll file it here until someone tells me otherwise. What's important is for the world to know that we have what's shown in our pictures in the Río Lagartos area of northern Yucatán.
GREEN FEATHER ALGA
The Ría Lagartos estuary into which the town of Río Lagartos juts has large areas so shallow that a regular motorboat's motor plows into the mud if you don't tilt it up. These shallows are carpeted with thick mats of sea-grass and large algae. As the boat floats over the shallows, sometimes for unclear reasons the vegetation changes. This week a certain patch caught my eye where a stringy network of something new was creeping atop the usual alga species. You can see what it looked like from the boat at http://www.backyardnature.net/n/14/141123cr.jpg.
It was easy enough to reach into the water and retrieve the creeper. It's shown at http://www.backyardnature.net/n/14/141123cs.jpg.
Notice how its rootlike rhizoids penetrate the filamentous alga it was growing atop. A close-up of featherlike fronds arising from one side of the stemlike stolon, with branching rhizoids on the stolon's opposite side, is shown at http://www.backyardnature.net/n/14/141123ct.jpg.
The feathery fronds of the plant photographed in the estuary's shallows reached only about 2cm long (¾ inch) but under other growing conditions they can reach 15-20 cm (6-8 inches). You can see a much larger frond washed up on sand on the ocean side of the barrier island opposite Río Lagartos at http://www.backyardnature.net/n/14/141123cy.jpg.
A pretty close-up of a tiny part of that washed-up frond is shown at http://www.backyardnature.net/n/14/141123cz.jpg.
Having no technical literature dealing with algae, an Internet search was conducted looking for images tagged with the keywords "green algae feather." Soon I was led to the genus Caulerpa, species of which often are referred to as green feather algae. However, about 35 species and varieties of Caulerpa are to be found in the Caribbean and western Atlantic Ocean, and several are very similar to ours, so at first I doubted our find could be identified to species level.
However, when the Ría Lagartos Biosphere Reserve was established, teams of biologists cooperated to list organisms found in the Reserve, and they identified nine Caulerpa species. Image searches on the Internet indicate that of those nine species CAULERPA SERTULARIOIDES looks most like what's in our pictures.
That's a clumsy and risky way to identify things, but the pictures sure look right, plus among the Caulerpa species Caulerpa sertularioides is the one whose habitat description most matches where we found ours.
Caulerpa sertularioides is described as occurring in scattered populations among seagrass beds, as well as attached to prop roots of the Red Mangrove. Here the entire estuary is fringed with Red Mangrove. It prefers more shallow depths than most other Caulerpa species, mostly less than 10m deep (100ft).
Also, we're well within the known distribution area of Caulerpa sertularioides, which extends from North Carolina south along the US coast into the Gulf of Mexico and throughout the Caribbean, and the southern Atlantic in general, south to Brazil. It also pops up here and there in places like northern Mexico's Pacific Coast, Australia's Great Barrier Reef, Papua New Guinea, and other places.
Aquarium enthusiasts often grow Green Feather Alga because it's more or less palatable to certain fish, easy to care for, reproduces by fragmentation, and it's pretty. In fact, it's so robust that along the northern Pacific coast of Costa Rica it's spreading rapidly, invasively, over coral reefs. However, Green Sea Turtles eat it, as well as several species of sea slug, including Oxynoe panamensis, which feeds exclusively on it.
WIND IN RÍO LAGARTOS
The same cold front that this week brought heavy snow and cold temperatures to eastern North America crossed the Gulf of Mexico and stalled for three days atop us. Here it was a real "norte," bringing only a few showers but enough chill for people to put on jackets. The wind simply roared through town. Flamingo tours and fishing were abandoned and all the town's colorful little boats were tied up at the storm wall or anchored just offshore, where they bobbed on white-topped, muddy waves like corks on choppy water.
When men can't take their boats out they stand around in little groups huddling out of the wind, holding their arms together, looking philosophical. The wind blows great brownish-green, soggy mounds of seaweed up against the storm wall, and foam from crashing waves jumps the wall and flies across the street like white tissue paper. Terns, gulls and pelicans line up atop the sides of boats and atop pylons out in the water, sometimes looking snug and resigned but other times harassed and uncertain, just like the whole town.
When the strongest gusts whirred around building corners and whistled through wires, people cocked their eyes and looked around. It reminded them of Hurricane Isadora in 2002, which devastated the mangroves and nearly destroyed the town. Everyone has stories. Everyone is still spooked by that hurricane, and everybody knows it's just a matter of time until an even worse one comes along. With this wind, and all these idle men huddling in corners, there were memories and apprehensions in the streets you didn't see, but felt.
At night, the usual sounds of distant barking dogs, motorbikes and people's TVs were drowned out by the wind's incessant roar. Inside the roar, somebody's loose sheet of tin convulsed against rafters it was gradually tearing itself from; a coconut palm's fronds noisily lashed the side of the house. It was like inside the head of an old person no longer able to hear quieter sounds, just the constant head-roar of irrepressible Nature taking its course, and the heartbeat of things falling apart, of impersonal, out-of-control lashings and beatings.
But, beautiful was the town with wind rampaging through it, beautiful when the sun began breaking through clouds, beautiful when things calmed down and men turned up along shore looking over their boats, and trading jokes with one another. Beautiful when the air was quiet enough for the odor of baking tortillas to waft through the streets, and beautiful when the terns, gulls and pelicans could soar and dive in their usual ways, exactly as terns, gulls and pelicans are supposed to.
FEATURED ESSAYS FROM THE PAST:
"iPhones & The Tree of Life" from the January 29, 2012 Newsletter, at http://www.backyardnature.net/n/p/120129.htm
"Hot, Breezy Afternoon Thoughts" from the February 25, 2006 Newsletter, at http://www.backyardnature.net/n/p/060225.htm
Best wishes to all Newsletter readers,
All previous Newsletters are archived at http://www.backyardnature.net/n/.