JIM CONRAD'S
NATURALIST NEWSLETTER
Issued in Río Lagartos, on the northern coast of
Yucatán, MÉXICO
in Ría Lagartos Biosphere Reserve

December 14, 2014

TRUE TULIP EGG CASES
After the last strong norte blew from the north for several days, the sea-side beach of the slender finger of land separating Ría Lagartos Estuary from the Gulf of Mexico was heaped knee deep with tons and tons of washed up seaweed and other goodies. One of the most curious and, for me, mysterious washed-up items on the beach was the white, pine-cone-like item shown at http://www.backyardnature.net/n/14/141214tu.jpg.

Individual sections of the washed-up object were not at all woody and stiff like pine-cone scales, though. Their tops were like shiny plastic bowls with frilly rims, as seen at http://www.backyardnature.net/n/14/141214tw.jpg.

The parts were bladder-like, shaped like white urns made of thin, translucent porcelain, but they felt rubbery, and were splotched with an interior-seeming raspberry hue, as you can see at http://www.backyardnature.net/n/14/141214tv.jpg.

At first I thought that this was some kind of freely floating alga depending on air-filled bladders for dispersal, which was the case with the Turbinaria alga we found on the Caribbean coast a while back. You can compare our current find with that alga at http://www.backyardnature.net/yucatan/turbinar.htm.

However, on the Internet no Turbinaria-like alga could be found looking like our washed-up discovery. Also, the object's parts looked too membranous and elegant to be of algal origin.

Eventually something else we once found on the Caribbean coast came to mind, something also formed of strung-together parts of animal origin. You can see that at http://www.backyardnature.net/yucatan/whelk.htm.

That's a Whelk egg-case, a Whelk being a medium to large, snail-like, marine mollusk. With the insight that our norte-delivered discovery might be a mollusk egg-case, finally pictures matching our discovery were found on the Internet. They were labeled as egg cases of the True Tulip, FASCIOLARIA TULIPA.

True Tulips are medium-sized, predatory, gastropod-type mollusks whose shells are whitish to tan, with rows of darker brownish blotches of various sizes. They're called tulips because the shells' overall shape supposedly looks like a closed tulip flower. Several species of the genus Fasciolaria are called tulips, but Fasciolaria tulipa is the "true" one, named by Linnaeus in 1758.

True Tulips are described as living in sand flats and seagrass beds at depths normally less than 30 feet (9m). They prey on bivalves such as clams as well as various other gastropods, including the closely related Banded Tulip and the over-hunted, vanishing Queen Conch. True Tulips turn up from North Carolina on the US southeastern coast south through the Gulf of Mexico and Caribbean to the coasts of northern South America and Brazil.

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TINY COILED SHELLS ON SHOALGRASS LEAVES
Last week we looked at Shoalgrass, which forms large underwater prairies in the Ría Lagartos Estuary. Our Shoalgrass Page is at http://www.backyardnature.net/yucatan/shoal-gr.htm.

If you go to that page, on Shoalgrass leaves in the top picture you can see tiny, white dots of something stuck to the leaves' flat surfaces. A close-up of some of those white dots is shown at http://www.backyardnature.net/n/14/141214tc.jpg.

When I first saw those objects through my hand lens I thought they might be snail shells that somehow ended up with their sides stuck to the leaves. However, I'd never heard of snails doing anything like that, plus these were very small to be snails. Eventually I remembered seeing tiny calcareous shells attached to much larger oyster shells, on the Yucatan's Caribbean beaches, as shown at http://www.backyardnature.net/yucatan/shell-tb.htm.

Those tiny calcareous shells had been produced by a kind of segmented worm called a polychaete. A quick Google search for polychaetes occurring on Shoalgrass leaves turned up pictures looking just like ours.

Our Shoalgrass-attached polychaete belongs to the genus SPIRORBIS, but its species goes unnamed. The Spirorbis Page at the website of the Smithsonian Marine Station at Fort Pierce, Florida advises us that "Identification of any Spirorbis specimens to species level is difficult, even for trained taxonomists." That page with much information on the Spirorbis life cycle is at http://www.sms.si.edu/irlspec/Spirorbis_spp.htm.

Ecologically, Spirorbis species are described as "seagrass calcareous epibionts." The word calcareous describes something mostly or partly made of calcium carbonate (like limestone and the mineral calcite), while "epibionts" are organisms attached to and living on the surface of another organism. Spirorbis species are polychaete worms living in coiled shells their own bodies secrete. They are not mollusks, like snails, but are segmented worms, like earthworms. Mollusks and segmented worms are classified in completely different phyla.

Spirorbis species are filter-feeding animals who use a "crown" of stiff tentacles at the exposed ends of their shell-sheltered bodies to capture food particles from water circulating around them. In the above picture, notice that the Shoalgrass leaves appear to be coated with slime. Such slime is referred to as "microbial film," or "bio-organic film," and studies show that Spirorbis prefer to live on such microbial-film-covered surfaces.

While handling the Spirorbis-covered Shoalgrass leaves, I could feel shells shatter, despite my attempts to handle them carefully. In fact, studies find that Spirorbis shells offer only limited protection from predators such as fish who might nibble at them.

Still, with so many Spirorbis shells attached to each Shoalgrass leaf in a vast underwater seagrass prairie, the sheer numbers of Spirorbis individuals in the Ría Lagartos Estuary is mind boggling. Besides occurring on Shoalgrass they also attach to Manatee Grass and Turtlegrass, which dominate in seagrass prairies elsewhere. A study in Florida found their density in certain areas to reach 1600 individuals per squire meter, a meter being a little longer than a yard. Here in the tropics perhaps they are even more abundant.

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ORANGE BALL SPONGE
After several days of a stiff "norte" blowing from the north, one of many ocean gems washed onto the ocean-side beach of the slender finger of land forming Ría Lagartos Estuary's northern border was the orange, 1¼-inch broad (33mm), honeycombed sphere shown at http://www.backyardnature.net/n/14/141214ob.jpg.

You can see that it's slightly hairy; a close-up of the surface better showing that is at http://www.backyardnature.net/n/14/141214oc.jpg.

It was a sponge, but not as spongy as most, in fact rather firm. Volunteer identifier Bea in snowy, gray Ontario was only too happy to figure out that it was the descriptively name Orange Ball Sponge, sometimes called Mango Sponge, CINACHYRELLA ALLOLADA.

At first I wasn't too sure about that name, because on the Internet most pictures of the sponge showed organisms covered with white to orangish fuzziness or, more commonly, they were generally fuzzy mottled with bald, orangish patches. Eventually it dawned on me that the fuzz had covered organisms that had been living and healthy when photographed, but on our washed-up one, the fuzz had been beat off.

The fuzz turned out to consist of tiny, needle-shaped "spicules." Spicules are diffused throughout a sponge's body to provide internal structure, and sometimes they cover a sponge's surface to offer defense against predators. The sharp, outward-pointing, hairlike spicules on our find were protective ones of the latter kind. Sponge spicules come in many forms, from our simple, needle-shaped ones, to cylindrical ones, to symmetrical and unsymmetrical forms composed of several slender needles, and their composition can be calcareous, siliceous or made of a collagen protein known as spongin. During serious sponge identification, spicule shape is of tremendous importance.

When holding an Orange Ball Sponge in the hand, the question arises of what kind of being this is. Is it animal, plant, or something else? Is it a colony of microscopic organisms, or a single living thing?

If our Orange Ball Sponge were a coral or bryozoan, it'd be a colony of tiny animals. Features suggesting that our sponge also is a colony and not just one animal include that it has no nervous, digestive or circulatory system, but rather must rely on a constant water flow through its body to obtain food and oxygen, and to remove wastes. Also, it lacks true tissues and organs, and displays no body symmetry.

However, despite this lack of features we think of as animals possessing, the Orange Ball Sponge as well as all other sponges are individual animals, albeit very simple ones. Animal traits they do have include that they are multicellular, heterotrophic (can't photosynthesize or otherwise manufacture their own carbon-based food), lack cell walls, and produce sperm cells.

Orange Ball Sponges often reach six inches across (15cm), so ours is a small one. They live in water 15-100 feet deep (5-30m), and normally occur in coral habitats, and on hard, often rocky, ocean floors.

In the US, Orange Ball Sponges occur on the Atlantic south of Cape Hatteras, North Carolina, all through the Gulf of Mexico and the Caribbean, and show up also on the coasts of Brazil and here and there in western Africa.

*****

SILVER GARDEN SPIDER
In knee-high strand-vegetation scrub near the water's edge of Ría Lagartos Estuary about ten kilometers east of Río Lagartos, a spider in her web caught my attention not only because she was boldly colored pale-white and black, but also because an eye-catching design graced the web's center. The design was X-shaped, fashioned of zigzagging strands of spider silk, with the spider occupying the X's center. You can see this at http://www.backyardnature.net/n/14/141214ar.jpg.

Mosquitoes that day were atrocious, even bunching up behind my glasses and getting into my eyes. My mosquitoes were a bonanza for the spider, for as I took these pictures one mosquito after another got snagged in the sticky web, causing the spider to rush out and grab it, return to her position in the X's center, and suck the mosquito's body dry. You can see her feasting on one at http://www.backyardnature.net/n/14/141214as.jpg.

A view of this spider's top side as she feeds on a mosquito is at http://www.backyardnature.net/n/14/141214at.jpg.

The web's zigzagging silk patterns -- such web decorations are known as "stabilimenta" -- as well as the spider's white front segment, or cephalothorax, its large size, its banded legs, and the bold patterns on its rear segment, or abdomen, all reminded me of the common Garden Spider so often seen in North America. You might enjoy comparing the common Garden Spider with our scrub discovery at http://www.backyardnature.net/n/a/gardspid.htm.

So many similarities between the two species make sense because our local scrub spider belongs to the same genus, Argiope. It's ARGIOPE ARGENTATA, usually called the Silver Garden Spider or Silver Argiope. Silver Garden Spiders, like common Garden Spiders, are distributed over a large part of the Americas, though on the average the Silver Argiope requires warmer, drier habitats than the Garden one. Silver Argiopes are found from the southern US south to Argentina. With such a large distribution, it's not surprising that pictures on the Internet show a variety of Silver Garden Spider abdomen designs. Even just locally, the designs vary tremendously.

Silver Garden Spiders can bite and their bite might hurt awhile, but for the vast majority of people they aren't serious. However, especially susceptible individuals may need to seek medical attention if bitten. Mainly, though, the spiders just don't bite unless handled, so don't handle them.

*****

CONGO MAHOE
At the weedy edge of a small patch of scrubby woods in the savanna south of Río Lagartos, pretty, apple-size, bowl-shaped, off-yellow flowers adorned a hairy-leafed tree, as shown at http://www.backyardnature.net/n/14/141214hi.jpg.

The flower astonished me. Obviously, with its many stamens united at their bases into a cylinder around the ovary's style -- forming what's called a 'staminal column' -- the tree is a member of the big Hibiscus Family. However, I'd never seen an hibiscus-type flower with its staminal column tilted so decidedly downward. A closer look at that amazing plunging column is provided at http://www.backyardnature.net/n/14/141214hj.jpg.

Not only is the column tilted, but its stamens cluster on the column's top side. The style's branched, purplish stigmatic area actually seems to rest on the corolla's lower surface. Also, notice the deep nectar pits at the column's base where hummingbirds are clearly invited to dip their beaks. Abundant whitish pollen splattered across the corolla's interior evidence recent visits by pollinators. A glance at the back of the flower shows that the fuzzy calyx also is a bit unusual, its acutely pointed sepals topping a broad calyx tube, and the calyx with its five sepals subtended by a circle of slender bracts, shown at http://www.backyardnature.net/n/14/141214hk.jpg.

Several flowers had matured to the point that their corollas had shriveled and dropped off leaving behind a tawny-colored, furry ovary developing within the cup of the leathery calyx, as shown at http://www.backyardnature.net/n/14/141214hl.jpg.

To identify this exotic-looking species I reviewed every member of the Hibiscus Family listed for the Yucatan, except for Hibiscus itself -- which I reckoned it couldn't possibly be because of that crazily tilted staminal column -- and found no matches. Maybe it was an invasive species or even something new.

But, the short story is that finally in desperation I looked among the Hibiscuses and... there it was. It's HIBISCUS CLYPEATUS, with the unlikely name of Congo Mahoe. James Macfadyen in his Flora of Jamaica suggests that the name was invented by African slaves who found it similar to something they'd left back home.

Still, this is an all-American native tree, and a fine one, endemic to southeastern Mexico, Belize, Guatemala and the Caribbean area.

Though with us the Congo Mahoe tends to emerge from dense, woods-edge thickets as if scared to show itself, when planted and cared for it makes a handsome tree with pretty, interesting flowers. Europe's Gardening.EU website says of the Congo Mahoe that "... during the summer it assumes a red colouring; the adult species are large in size and reach 17 m in height." 17m is 56 feet. Nothing is said of its cold hardiness.

As with many woody members of the Hibiscus family, the tree's inner bark is toughly fibrous. The fibers have been used traditionally for making cord, whips and lashes.

*****

STENOCEREUS ORGAN-PIPE CACTUS
Up the Ría Lagaratos Estuary a few kilometers, a large, columnar, organ-pipe-type cactus beckoned from the shore-side scrub, looking a little different from the usual ones. Even from a distance, spherical fruits could be seen growing from its sides. I just had a feeling that this would be a good find. You can see it rising above its scrubby compatriots at http://www.backyardnature.net/n/14/141214st.jpg.

Its arms were of the kind with thick ridges, atop which clusters of spines projected in all directions from a common base. You can see this on a column top with an immature fruit attached at http://www.backyardnature.net/n/14/141214su.jpg.

A close-up of the immature fruit bristling with red spines arising from fuzzy bases is shown at http://www.backyardnature.net/n/14/141214sv.jpg.

The pinkish, narrow spines on the developing ovary will fall off as the fruit matures. A closer look at a cluster of whitish spines that are not deciduous, occurring along the rib tops, is seen at http://www.backyardnature.net/n/14/141214ss.jpg.

Once these details were taken in, I realized that we'd encountered a very similar cactus like this before -- back in the arid mountains of Querétaro in north-central Mexico. A picture of that handsome cactus, and a description of birds and insects feeding on its ripe fruits filled with red, sweet, wet pulp and seeds, is at http://www.backyardnature.net/q/organ-pi.htm.

Our Querétaro organ-pipe cactus was Stenocereus queretaroensis, endemic just to arid north-central Mexico. Our present find also is a member of the genus Stenocereus. It's STENOCEREUS LAEVIGATUS, endemic to arid regions of Guatemala and Mexico's southernmost state, Chiapas, and apparently to the Yucatan. I say apparently because the sources I find don't mention it as occurring here, except that it's listed in the Ría Lagartos Biosphere Management Program publication for our immediate area.

The cactus grew near ancient Maya ruins. Could the ancient Maya, known to trade salt from our local salt pans with locations as far south as the coasts of Guatemala and Honduras, have brought this cactus here from down south? They might have, because people as well as birds and insects love to feed on the fruits' sweet pulp. The fruits are called pitayas, though that name is applied to just about any large, edible cactus fruit.

*****

MANATEE GRASS
Massive beds of seagrass are profoundly important to coastal ecosystems. Seagrass roots anchor seabeds in place, herbivorous animals graze on them, and all kinds of aquatic creatures shelter within the submerged prairies they form. Beds of seagrass consist of different species, depending on what part of the world they're found in. Along the Yucatan's coasts, the four main seagrass species are Shoalgrass, Turtlegrass, Manatee grass and Widgeon Grass. All these are flowering plants, and monocots, like grasses, but none of them are member of the Grass Family, so despite their names none is a real grass.

Here on the Yucatan's north-central coast, the dominant seagrass on our muddy-bottomed Ría Lagartos Estuary's muddy floor is Shoalgrass, which we looked at last week, shown and described at http://www.backyardnature.net/yucatan/shoal-gr.htm.

However, in shallows offshore in the salty Gulf of Mexico itself, Shoalgrass gives way to Manatee Grass, SYRINGODIUM FILIFORME. During the last norte, or strong wind out of the north lasting for several days, enormous amounts of seaweed washed up on beaches, and most of the bulk of that seaweed was Manatee Grass. You can see what a small part of the wash-up looked like at http://www.backyardnature.net/n/14/141214sw.jpg.

Inside the huge heap you could disentangle individual lengths of Manatee Grass rhizomes sprouting upward-directed, equally spaced stems along its length, with two or three cylindrical leaves issuing from each stem, as shown at http://www.backyardnature.net/n/14/141214ma.jpg.

At the base of each leaf there's a little ear, or "auricle," as shown at http://www.backyardnature.net/n/14/141214mb.jpg.

In that picture the leaf extends toward the picture's top, right corner, while the stem is directed toward the top, left. Note that the leaf base is round in cross-section, or cylindrical. That's an important feature, because at first glance Shoalgrass and Manatee Grass are very similar. However, Shoalgrass produces flat leaves, like those of a real grass, while Manatee Grass's leaves are cylindrical. Both Shoalgrass and Manatee Grass belong to the Manatee-Grass Family, the Cymodoceaceae, a small family whose members inhabit aquatic environments of the world's tropical and subtropical waters.

Manatee Grass occurs on submerged sand and mud of coastal areas surrounding the Gulf of Mexico and the Caribbean, south to northern South America.

In Florida, Manatee Grass is famous as Manatee food. Here on the Yucatan's northern coast at one time Manatees existed, and habitat for them -- extensive beds of Manatee Grass and Shoalgrass -- still exists, but apparently now Manatees are extinct in the Ría Lagartos Biosphere Reserve. Studies suggest that their disappearance was caused by hunting, drowning in fishermen's nets, and being injured by boat propellers.

Maybe someday Manatees will return here. From the amount of Manatee Grass washed upon beaches during the last norte, just offshore and in the estuaries, enormous underwater prairies of seagrass await them.

*****

BURHEAD
On the road through the marshes between Río Lagartos and San Felipe, at the muddy edge of a shallow pond on the verge of drying up, here at the beginning of the dry season a nice colony of semi-aquatic plants turned up. Their thigh-high, narrow leaves looked a little like the North's weedy Narrow-leafed Plantain, but unlike the weedy plantain these plants produced flowering heads with pretty, white blossoms in widely spaced whorls, as shown at http://www.backyardnature.net/n/14/141214ec.jpg.

The narrow leaves were interestingly veined, with many cross-veins connecting long primary veins that ran the leaves' lengths, as shown at http://www.backyardnature.net/n/14/141214ed.jpg.

Each flower bore three white petals and about ten stamens, but instead of having one pistil in the blossom's center -- the usual situation -- there were many packed closely together into a greenish eye, as shown at http://www.backyardnature.net/n/14/141214ef.jpg.

These flowers must have been late-season ones, for most of the pond's many plants bore pea-sized, burry heads consisting of numerous sharp-topped, achene-type fruits, as shown at http://www.backyardnature.net/n/14/141214eg.jpg.

In North America maybe the best known members of the family to which this plant belongs are the aquatic arrowheads or duck-potatos, which produce similar flowers and fruiting heads, but whose arrow-shaped leaves with long, sharp-pointed, lower lobes are very unlike our currant plant's. You might enjoy comparing our present plant with an arrowhead species at http://www.backyardnature.net/n/h/calycina.htm.

Arrowhead/duck-potato species and our current roadside plant all belong to the Water-Plantain Family, the ALISMACEAE, whose members are mostly aquatic and semiaquatic. In many older books our plant is listed as Echinodorus andrieuxii but now most experts use the name ECHINODORUS SUBALATUS. The species isn't well known in the English speaking world so it bears no good English name. However, members of the genus Echinodorus often are called Burheads or Amazon Sword Plants, so we'll just call our plant Burhead.

Burhead occurs generally in tropical American wet places, from Mexico and the Caribbean south deep into South America.

Our North American arrowheads/duck-potatoes often produce starchy tubers that ducks as well as very hungry people eat, but Burheads don't produce such tubers. However, it's easy to visualize sparrows clinging to the plant's fruiting heads, nibbling on tiny, achene-type fruits.

*****

THE RUINS OF EMAL
Maybe 15kms up the Ría Lagartos Estuary from Río Lagartos, our flamingo tour crew decided to visit Emal. There on the estuary's shore, Emal catches your attention from far off because an ancient Maya ruin rises well above any other feature in the region's flat, near-sea-level landscape. You can see the scrub- and cactus-mantled archaeological mound at http://www.backyardnature.net/n/14/141214em.jpg.

The ruins are from a time when Pre-Columbian Maya collected salt from the surrounding salt pans -- as still is done on a large commercial scale. The salt probably was traded throughout much of Mesoamerica -- approximately from central Mexico to northern Costa Rica. Some think that Chichén Itzá's grandeur and power were based on its control of the salt trade, and Emal was their main salt source.

However, the ruins at Emal are so modest that it's hard to believe that the site was so important. Some archaeologists reason that this can best be explained by Emal having been under firm control of a distant power -- probably Chichén Itzá. Maybe Chichén Itzá's leadership used Emal's salt strictly to enhance their own power and glory.

These are fascinating thoughts, but so far they are only guesses.

During our visit to Emal, a new-to-me cactus grew on the ruins. When I identified it, it turned out to be rare and somewhat out of place in this area, being more at home farther south in Guatemala and Chiapas, so I began digging for more information. That's how I stumbled upon a webpage entitled "Emal Archaeological Project," where the Project's leader wrote, "Here you will find all of our field data, journals, publications, maps, and other information." The information there offers fascinating glimpses into how the world of Maya archaeology works. There are field maps, notes on funding efforts (from the National Geographic Society), videos of previous work being done there, and the full project proposal (in Spanish). The webpage is at https://sites.google.com/site/emalarchaeologicalproject/.

Elsewhere on the Internet the 2005 book by Susan Kepecs and Rani Alexander entitled The Postclassic to Spanish-era Transition in Mesoamerica: Archaeological Perspectives tells us that according to the ancient native books of Chilam Balam, during times of the Maya Empire Emal was ruled by the Chan lineage. The Chans of Emal maintained a lose economic alliance with kin in southern Quintana Roo, on the Yucatan Peninsula's Caribbean coast. Both Chan groups were called "the guardians of the sands, the guardians of the seas." Kepecs and Alexander say that in the late 1400s the Quintana Roo Chans specialized in building large trade canoes, which must have carried salt and other goods around the peninsula to ports on the Gulf of Mexico and as far south as Honduras.

It'll be fun keeping up with the Emal Archaeological Project through postings on the above web page. Maybe we'll even get to meet some of the archaeologists. The thought has arisen that maybe my rare cactus grew upon the ruins at Emal because ancient Maya canoes coming to Emal for salt brought the cactus's ancestors up from Guatemala. That's conceivable, because the cactus's fruits are good to eat.

*****

FEATURED ESSAYS FROM THE PAST:

"Laziness & the Water Snake" from the June 23, 2008 Newsletter, at http://www.backyardnature.net/n/p/080623.htm

"Late December Light" from the December 18, 2011 Newsletter, at http://www.backyardnature.net/n/p/111218.htm

*****

Best wishes to all Newsletter readers,

Jim

All previous Newsletters are archived at http://www.backyardnature.net/n/.