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

February 22, 2015

SARGASSUM FISH
A little after dawn the tide was so low that Rayo and I could wade across what normally is a deeply submerged field of Shoalgrass, and we were seeing amazing things. When Rayo let out a whoop and used his cap to scoop up something from the water, I knew he'd spotted something good, because he liked that cap. You can see what he caught after it was released into the cut-off bottom of a plastic jug at http://www.backyardnature.net/n/15/150222fk.jpg.

Back at the restaurant/ecotour office the elegant little 4cm fish (1.5in) was transferred into an aquarium, Rayo illuminated it from above with his cellphone light, and I got the picture at http://www.backyardnature.net/n/15/150222fi.jpg.

You can see that by then the fish's patterns had changed a lot. When the fish turned around to face me, it was hard to figure out what was what, as seen at http://www.backyardnature.net/n/15/150222fj.jpg.

Before long the whole crew was angling for a closer look, everyone guessing at its name but no one really knowing. They couldn't believe they'd spent their whole lives here fishing and leading tours but hadn't known that such an awesome being lived in the Shoalgrass right in front of town. My biologist friend Willie went onto the Internet looking for pictures, and before long he'd IDd it, announcing to all that it was a Sargassum Fish, HISTRIO HISTRIO.

The Sargassum Fish occurs in tropical and subtropical waters nearly worldwide, at depths of down to 10m (33 ft), especially where drifting seaweed accumulates, such as Sargasso alga, which we have a lot of here, two species of it. One species is profiled at http://www.backyardnature.net/yucatan/sargasso.htm.

The Sargassum fish grows to 20cm long (7.9 in), so ours is a young one. It's described as a voracious ambush-predator, and a cannibal that eats smaller members of its own species. It stalks its prey amid tangles of aquatic plants, dangling its nose ornament to attract small fish, shrimp, and other invertebrates to within gulping distance. It can expand its mouth to many times its original size in a fraction of a second, drawing prey in via suction, and can swallow prey larger than itself. When something chases it, it can jump from the water onto the top of floating vegetation and wait until its enemy goes away. Rayo thinks that that's why he saw the fish and could catch him -- the fish had jumped from the water onto a tangle of Shoalgrass.

One behavior we often see in the aquarium is that the fish will sidle up to a vertically standing aquatic plant and with his side fin, the pectoral, pull the plant's stem closer to its body. He may do this with plants on both sides. The effect is to hide the fish better among the vegetation, and the technique is very effective. Several times we've decided that he must have disappeared someplace, only later to find him swimming around as always.

*****

OCTOPUS
At low tide a small slab of concrete lying on normally submerged mud was turned over, revealing the strange object shown at http://www.backyardnature.net/n/15/150222oc.jpg.

"¡Pulpo!" Rayo exclaimed, the name translating to "octopus," though the baseball-size thing didn't look like an octopus to me. I started to poke the discovery with my finger but Rayo held back my hand saying I might get bitten. Then he inserted his own fingers below the object and began prying it from the concrete. Once the creature was half unstuck, its octopus nature became more apparent, and I could see that we'd been looking at the octopus's upside-down bottom, its eight arms being curled over and under the main part of its body. You can see the half-unstuck octopus at http://www.backyardnature.net/n/15/150222od.jpg.

Once the octopus flipped itself right side up, it took shape, its two big eyes bulging atop its "head," as shown at http://www.backyardnature.net/n/15/150222oe.jpg.

If you're unaccustomed to the octopus manner of being, it may seem that the main part of the octopus body is the broad, flat area to the left of the eyes, and that the fleshy blob at the eyes' right is something like a very large nose with flaring nostrils, but it's the other way around. The fleshy item on the right is the body containing stomach, intestines, liver, gills, kidney and such, while the broad, flat area to the eyes' left is just a web of tissue stretched between the front arms. In that picture, the octopus is moving from right to left, or "forward," with the body being pulled along behind.

A close-up showing the animal's pretty skin and color patterns is at http://www.backyardnature.net/n/15/150222og.jpg.

Rayo couldn't restrain himself from lifting up the octopus for a better view, shown at http://www.backyardnature.net/n/15/150222of.jpg.

A close-up of the center area of the octopus's bottom showed mushroom-like suction cups on the arms' lower surfaces, shown at http://www.backyardnature.net/n/15/150222oh.jpg.

As Rayo handled the creature, its arms constantly wrapped around his hands, with the suction cups latching onto his skin. When he pulled the arms loose, it sounded like Velcro being ripped off. In the above picture, at the right of the picture, in the center of the area without suction cups, notice the slightly dark bulge in the area's center. That's the octopus's birdlike beak withdrawn so that it's hardly visible, and that's what Rayo had been afraid I'd poke and get bitten with. It also explains why Rayo had felt comfortable sliding his fingers beneath the blob stuck to the concrete, for there's no beak on that side. Remember that the concrete slab had been flipped over, so before we came the octopus's bottom with its beak had been directed toward the mud floor, and the slab had been his ceiling.

Judkins et al in their 2009 "Checklist of Cephalopods from the Gulf of Mexico" lists fourteen species in the Octopus Family, the Octopodidae, found in the Gulf of Mexico. Of these, two species are commonly encountered in waters of the Yucatan Peninsula. One is the Common Octopus, Octopus vulgaris, of nearly worldwide distribution, and the other is the endemic Octopus maya, known in the literature as the Mexican Four-eyed Octopus. Locally, Octopus vulgaris is known as "Pulpo Patón," while Octopus maya is "Pulpo Rojo," the word "rojo" meaning red, and referring to the mollusk's reddish body. During octopus fishing season about 80% of the Yucatan's catch is of Octopus maya, while only 20-30% is Octopus vulgaris. So, which species do we have?

Distinguishing the two species can be hard for beginning octopus identifiers, especially because individuals of both species change color drastically,the color schemes between species overlaps a good bit, and the shapes of individuals is so changeable that it's hard to say what's the "real shape." After speaking with the most experienced octopus fishermen in my neighborhood, and showing them our pictures, the consensus is that our octopus is the Mexican Four-eye, Octopus maya.

My impression is that the best field mark for separating the two species is that the Common Octopus's body is thickly pear-shaped, almost spherical, while that of our Octopus maya is more compressed. In our pictures, much of the body's width when seen from above is provided by flaps of tissue flaring from the bulging part of the body. And that bulging part is much longer than broad, not almost spherical, as with the Common's.

Bottom-dwelling octopuses such as Octopus maya mainly feed on crabs, polychaete worms, and their fellow mollusks such as whelks and clams.

Octopuses in general are regarded as possibly more intelligent than any other order of invertebrate. Maze and problem-solving experiments have suggested a memory system that can store both short- and long-term memory.

The February 18, 2015 issue of the online "Diario de Yucatán" reports that in 2014 more than 22,000 metric tons (24.250 US short tons) of octopus were caught in waters of the Yucatan Peninsula. When I recall how many boats went out during harvesting season, and how many trucks filled with refrigerated octopus bodies passed by my door, I don't doubt the numbers at all, and wonder how long such exploitation can last.

*****

DIGGING LIGHTNING WHELK
At dawn during an exceptionally low tide we weren't the only ones wandering around on mudflats that normally are covered with water; several other local folks widely separated from one slogged back and forth, carrying buckets. Rayo told me they were digging "conchas," to eat. The word "conchas" means "shells," but here the word also applies to the living mollusks producing what northerners normally think of as seashells. Then Rayo spotted the very thing the others were looking for, the nose of a shell barely poking from the mud, shown at http://www.backyardnature.net/n/15/150222wh.jpg.

Being careful not to hurt the creature, I excavated mud from around the shell and was surprised that it turned out to be so large. You can see the extracted muddy creature with its body slowly retracting into its shell at http://www.backyardnature.net/n/15/150222wi.jpg.

The shell's top side is shown, glowing with dawn's golden light, at http://www.backyardnature.net/n/15/150222wj.jpg.

Amid soupy mud left pooled in the depression from which the mollusk had been removed was a string of egg cases our mollusk had been producing, shown at http://www.backyardnature.net/n/15/150222wl.jpg.

Volunteer identifier Bea in icy Ontario just bought herself a used Peterson field guide to sea shells, so off these pictures went to Bea, who soon determined that we had a Lightning Whelk, BUSYCON PERVERSUM. The "perversum" in the name derives from the fact that this species' shell makes a "left handed" spiral, which seems a little perverse in a world of mostly "right handed" spiraling things. Apparently this was special enough that Native Americans once used these shells in religious ceremonies.

But native Americans also harvested them for food, just like the local folks that morning, because Lightning Whelks are highly edible. Also, at one time people used the shells as scrapers, gouges and even cups and bowls. When you read how whelks were harvested in the past, and see how they're being dug up even today, it's amazing that the species survives.

Lightning Whelks are described as inhabiting bottoms of shallow bays in sand or mud near Shoalgrass or Turtlegrass meadows -- ours were near Shoalgrass meadows -- from the western Atlantic at North Carolina in the US, south through the Gulf of Mexico to the Yucatan Peninsula.

Lightning Whelks mainly feed on bivalves such as oysters, clams, and scallops, and in turn are fed upon by gulls, crabs, and other whelks. Their strings of egg-bearing capsules normally range from about 11 to 33 inches (27 to 83 cm) long, with each string holding up to 145 capsules, and each capsule holding 20 to 100 eggs, though only about 8 to 13 eggs in each capsule hatch.

*****

POLYCHAETES IN THE MUDFLATS
A couple of years ago in Texas, beneath the microscope's lenses, we found a tiny worm living in a drop of water from the Dry Frio River behind the cabin, still shown at http://www.backyardnature.net/n/13/130303wm.jpg.

The worm turned out to be an annelid, or segmented worm, like the common earthworm, but it was a special class of annelid, one known as a polychaete, or "bristle worm." I'd been surprised to find such a tiny, free-living polychaete because my impression of what a polychaete was had been based on the one we'd found previously on the Yucatan's Caribbean coast, inhabiting carbonate tubes plastered onto the inner walls of seashells, as shown at http://www.backyardnature.net/n/11/110911wt.jpg.

That was the beginning of my understanding that polychaetes are a varied lot. In fact, here we've already found other polychaete species with different manners of living -- one living in tubes composed of cemented white sand, and another in calcareous tubes looking like tiny white snail shells attached sideways on Shoalgrass leaves. In our recent February 15th Newsletter, we saw how Lugworms, also a kind of polychaete, excrete sizable coiled sand "castings" onto the beach. You can review these various polychaete species on our Worm Index Page at http://www.backyardnature.net/n/worms.htm.

This week when Rayo and I went onto the usually flooded mudflats in front of Río Lagartos, it was like taking a university course in polychaete diversity. We'd gone there to find something Rayo had seen but couldn't figure out. He'd described it as like a long weed root that was hollow inside and outside was covered with small seashells and shell fragments. As our boat approached the mudflat where the mystery item had been spotted, we saw what's shown at http://www.backyardnature.net/n/15/150222pw.jpg.

With slender Black Mangrove pneumatophores pointing skyward in the background, the mudflat was populated with piles of mud exactly like the Lugworm castings profiled in our February 15th Newsletter -- where our Lugworms were identified as Arenicola brasiliensis. But unlike with our earlier discovery, here were acres of them. A close-up of one of these mudflat castings is shown at http://www.backyardnature.net/n/15/150222pv.jpg.

Quickly Rayo found one of his mystery items looking like a weed taproot, poking from the mud. It's shown at http://www.backyardnature.net/n/15/150222pr.jpg.

Shells and shell fragments were indeed stuck to it, as shown at http://www.backyardnature.net/n/15/150222pt.jpg.

And inside it was indeed hollow, as shown at http://www.backyardnature.net/n/15/150222ps.jpg.

Something wormlike had occupied this tube. Remembering that polychaetes often encrust their tube exteriors with shells and shell fragments, it was easy to decide that probably this was a polychaete tube. Earlier when we'd dug several inches around our Lugworm burrow, there'd been no such shell-encrusted casing, so this seemed to have been made by yet a different polychaete species.

This wasn't the end of our polychaete lessons, though. In shallow water at the mudflat's edge many holes were issuing flaccid balloons of gelatinous material that swung back and forth with the advance and retreat of each wave, as shown at http://www.backyardnature.net/n/15/150222po.jpg.

In my hand the gelatinous blobs looked like what's shown at http://www.backyardnature.net/n/15/150222pp.jpg.

Inside each blob were suspended thousands of tiny specks, presumably eggs -- and from what I could determine on the Internet later they were polychaete eggs -- shown closer up at http://www.backyardnature.net/n/15/150222pq.jpg.

Up on the mud from which water had receded, an extraordinarily long egg mass stretched from its hole past Rayo's colorfully tattooed legs, shown at http://www.backyardnature.net/n/15/150222pu.jpg.

Realizing what these gelatinous egg masses were, and remembering that through clear water we've always seen them on the estuary floor below the boat -- and wondered what they were -- it became clear that polychaete influence doesn't end at the low water mark. This mudflat and the whole estuary -- especially when you remember those tiny ones in white, snail-like tubes speckling all Shoalgrass leaves -- is a polychaete urban zone, a niche of Nature where polychaetes are a dominant life form.

Polychaetes fossils are known from the early Cambrian Period, over 500 millions years ago, from a time when the Earth's land masses still bore no life, for all living things occupied the seas. Taxonomically, the Class Polychaeta comprises about 10,000 species worldwide. María Ana Tovar-Hernández et al writing in the online Mexican Government "Revista mexicana de biodiversidad," in 2014, says that in Mexico we have about 1500 polychaete species in 63 families and 460 genera. Though our Texas polychaete was a freshwater species, polychaetes mostly are marine. With 1500 Mexican species, most of them marine, no wonder we're finding such a diversity of polychaetes here along the coast.

Polychaetes with their extensive burrowing aerate the soil and "plow" it, keeping the soil from compacting. Their "maintenance" of the soil enables other species to colonize, thus adding diversity and stability to the greater ecosystem. Earth-burrowing polychaetes do for submerged and water-saturated soil what earthworms do for dry land ecology. And remember that Charles Darwin wrote of earthworms that "...it may be doubted if there are any other animals which have played such an important part in the history of the world as these lowly organized creatures."

****

IMMATURE GREAT BLACK HAWK
Here along the Yucatan coast we have both the Common Black Hawk and the Great Black Hawk. The Great Black Hawk doesn't show up in the interior, though the Common does. The two species are very similar. The Great Black is larger -- its "length" being given as 22in (56cm) compared to the Common's 19.5in (50cm) -- but that's hard to judge in the field, and other differences can be hard to see, too. Distinguishing the two can be a challenge, at least from a distance.

Both black hawk species are black, but their juvenile plumages are brown and white. This week I got a good look at an immature Great Black, whose picture is shown, to help with future identification challenges, at http://www.backyardnature.net/n/15/150222gc.jpg.

There we can see that the legs bear several slender, horizontal bars. Legs on the Common Black immature bear only three or so thicker bars. Another shot is at http://www.backyardnature.net/n/15/150222gb.jpg.

The practiced eye notices the tail length, which is longer than the Common Black's. The bird in our pictures must be transitioning from its juvenile plumage to adult, for normally the immature's tail bears many horizontal dark bands on a tan background. This bird's tail with only one broad white band on a blackish background is more typical of the mature bird's.

*****

FLOCKS OF IMMATURE WHITE FLAMINGOS
Nowadays in the estuary you see flocks consisting of nothing but immature flamingos who are white because they haven't eaten enough carotene-bearing algae and small crustaceans to earn their pinkness. You can see part of one flock at http://www.backyardnature.net/n/15/150222fl.jpg.

*****

SPHINGA TREE
Nowadays fairly commonly flowering along the coastal road between Río Lagartos and San Felipe is a smallish tree with clusters of brilliantly white flowers issuing many slender stamens in shaving-brush fashion, as seen at http://www.backyardnature.net/n/15/150222s0.jpg.

The flowers' stamens droop soon after sunrise, so the flower clusters' esthetic impact is mainly at dawn, suggesting -- along with the pure white color -- that the blossoms depend on nocturnal moths and/or bats for pollination. A close-up showing some still-perky flowers, and how the stamens' long filaments unite at their bases into cylinders surrounding the bases of very long, slender styles, is at http://www.backyardnature.net/n/15/150222s1.jpg.

This tree's leaves are twice pinnately compound. Most twice pinnately compound leaves consist of many small leaflets but this tree's leaves have just a few larger ones, as seen at http://www.backyardnature.net/n/15/150222s2.jpg.

Fortunately -- because I'd not encountered this combination of features before, so it was something new for me -- a few flat-podded, legume-type fruits are being produced, helping with the identification process, as shown at http://www.backyardnature.net/n/15/150222s3.jpg.

Recognizing the fruit as a legume, which is the fruit-type produced by the huge Bean Family, plus the fact that the doubly compound leaves are like those of many Bean Family trees, as well as that the flowers are similar to those of acacias, which are members of the Bean Family, it was clear that our mysterious tree with its brilliantly white, shaving-brush flowers was a member of the Bean Family. Another feature worth documenting was the way pairs of broad-based, curved-back, blood-drawing spines occurred at the bases of many leaf petioles, as seen at http://www.backyardnature.net/n/15/150222s4.jpg.

All these field marks lead us directly to a Bean Family genus I'd never heard of, the genus Sphinga. Sphinga embraces only three species, of which two occur in the Yucatan, the third in Cuba. Our species is SPHINGA PLATYLOBA, found from central Mexico south through Central America into northern South America. The English-speaking world has ignored the species, so there's no decent English name. In fact I can't find a good Spanish name, either. The Maya call it Muk or Nuk, since they don't much distinguish between Ms and Ns at the beginning of words. Therefore, we'll just call it Sphinga.

For a long time, Sphinga trees have been troublesome to taxonomists. During recent years Sphinga species have resided in the genera Acacia, Pithecellobium, Havardia and Feuilleea, and who knows where they'll be ten years from now? It surprises some that in these days there could be a perfectly good tree commonly encountered from central Mexico to Venezuela, for which somehow no common or technical name convincingly exists, but that's the case here.

*****

YELLOW-FLOWERED "WILD SAGE"
We've run into LANTANA CAMARA, sometimes called Wild Sage, several times in the US and Mexico. We've seen it as a weed, as a wild-growing invasive and as a treasured garden ornamental, and always it's been a challenge to make sure of its identity. That's because the species is so remarkably variable, especially in its flower color. Nowadays Wild Sage grows as a knee-high, weedy shrub along the coastal road, producing striking yellow flowers, as shown at http://www.backyardnature.net/n/15/150222la.jpg.

Most Wild Sage flowering heads we've encountered bear blossoms of two or more colors, the individual flowers in the heads usually yellow, red or pink though other colors are possible. The flowering heads on our plants here are just yellow. A close-up of a flowering head from below, showing the bilaterally symmetrical flowers' curved corolla tubes and the leafy bracts subtending the lower flowers is at http://www.backyardnature.net/n/15/150222lb.jpg.

A closer look at the face of one corolla is at http://www.backyardnature.net/n/15/150222lc.jpg.

A look at the shrub's mint-like leaves -- despite their belonging to the Verbena Family, not the Mint -- is at http://www.backyardnature.net/n/15/150222ld.jpg.

Our yellow-flowered Wild Sages usually are designated as the variety "flava," the word "flava" being Latin for yellow. Several varieties are known.

The bush's crushed leaves produce a strong smell, not necessarily bad but also not minty-sweet. Green Deane at his EatTheWeeds.com website says of the Wild Sage that "Unripe berries have killed children and the foliage has killed livestock," but he says he nibbles on the mature fruits, though never many. I've nibbled on them, too, with no problem, especially because they were so bitter that having more than a nibble was out of the question.

As you might expect from any common, odoriferous plant, Lantana camara traditionally has been used medicinally. The online "Atlas de las Plantas de la Medicina Tradicional Mexican" reports that in Mexico teas have been brewed from the leaves, stems and roots to deal with many kinds of internal problems, such as stomach ache, liver ailment, colic and "rheumatism," but also several female troubles including childbirth issues, and a host of other ailments.

Lantana camara is a common, conspicuous and interesting plant, and it's worth the effort to learn its many flower color variations.

*****

SOUTHERN CATTAILS
In this area along the edges of many ponds with brackish to nearly fresh water you see dense thickets of ten-ft-high (3m) cattails, as shown at http://www.backyardnature.net/n/15/150222tw.jpg.

Nowadays the cattails are producing flowering and fruiting heads, which look much more like skewered frankfurters than cat tails, as seen at http://www.backyardnature.net/n/15/150222ty.jpg.

In cattails, male flowers are densely arranged in spikes atop the flowering stem, or rachis. Each male spike is separated from the much thicker female spike it by a short section of naked rachis. A picture showing the bottom of a male spike, with the anthers turning brown and shriveling after having already released their pollen, separated by the naked rachis from the top of a maturing female spike below, is seen at http://www.backyardnature.net/n/15/150222tx.jpg.

In that picture, male flowers are at the top, and maturing ovaries of female flowers are at the bottom, where the ovaries' tops create a shiny, green, hard-looking floor beneath a layer of brownish fuzz. The fuzz consists of maturing styles and stigmas, and probably protects the maturing ovaries from sunlight and temperatures extremes.

If you remove flowers from a section of male spike you can see the 2.5mm tall (1/10th in) anthers stacked next to one another, as shown at http://www.backyardnature.net/n/15/150222tz.jpg.

In the particular population I photographed, many plants bore two skewered-frankfurter-like groupings of female flowers below the male section instead of the usual one. I'd seen such instances of two female sections being produced on one axis before, though not as commonly occurring as here. I wondered if these cattails might be a different species from what I thought they were, which was the Southern Cattail, TYPHA DOMINGENSIS, which we also had in southern Texas. But, no, taxonomists consider all our Yucatan cattails to be Southern Cattails.

Southern Cattail is a very successful species, considered to be native worldwide in warmer countries. In wetlands where the soil and/or vegetation is disturbed, Southern Cattail moves in and can form pure, one-species stands. The species thrives in waters with low oxygen content and survives brackish water, plus in areas where humans alternately drain and flood land without regard to natural cycles, Southern Cattail has an advantage over other species. However, in undisturbed wetlands with low nutrient levels, it grows only sparsely.

Traditionally, in many cultures Southern Cattail leaves have been used for weaving. The online "Invasive Species Compendium" reports that in July, 2007, in central Mexico an armful of Southern Cattail leaves sold for US $1-3. The Southern Cattail's rhizomes are starchy and nutritious, but so fibrous that they're hard to eat. Drying and pounding them can made them edible. At a certain time of year, just before the male flowers release their protein-rich pollen, the male spikes can be roasted and daubed with butter, and eaten like corn on the cob.

*****

FEATURED ESSAYS FROM THE PAST:

"Dumb Love & Patriotism" from the July 6, 2006 Newsletter, at http://www.backyardnature.net/n/p/060706.htm

"Drumbeat in The Alux Grove" from the November 29, 2009 Newsletter, at http://www.backyardnature.net/n/p/091129.htm

*****

Best wishes to all Newsletter readers,

Jim

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