March 8, 2019
SNAKE COILED ON A PINEAPPLE
In the rancho's garden this week I was showing around a couple of Swiss visitors when one of them said, "Ach, eine Schlange!"
And it was true: In the crimson center of a pineapple plant's rosette of tough, spiny-edged leaves there lay curled up atop a half-grown pineapple a little snake about two feet long (60cm). Before I could get my camera set up he had slithered from his picturesque podium, but I managed to grab him before he got away, as you can see at https://www.backyardnature.net/n/19/190308bi.jpg
I wanted to catch him because he didn't look like any snake I'd seen before. This being the case, I made sure to take good close-ups of the snake's scale patterns, because their arrangement is diagnostic in snake identification. The most important are those on the head, whose pattern is clearly revealed at https://www.backyardnature.net/n/19/190308bj.jpg
You might enjoy comparing the above picture with my general map of snake head scales at https://www.backyardnature.net/pix/snakscal.jpg
Most importantly, on our garden snake there we see 6 supralabials (scales forming the top lip), 8 infralabials (bottom lip), and 1 loreal (between the scale before the eye and the scale with the nose hole). Scales atop the head are shown at https://www.backyardnature.net/n/19/190308bk.jpg
A side view showing dorsal scales on one side of the snake is seen at https://www.backyardnature.net/n/19/190308bl.jpg
In that picture, the scales at the very bottom are broad ventral scales running along the snake's underside, while the dorsals arrange themselves above the ventrals. I count 7 diagonally ascending lines of dorsal scales, and one set of scales running atop the spine, so with two sides that's 7 + 1 +7=15, and that number 15 excludes the vast majority of other species. Also, it's important to notice that the scales are smooth, with no ridge-like "keels" crossing them horizontally, plus a very distinctive feature of these scales is that each along is bordered one two sides with golden fringes. Another determinative scale feature is shown at https://www.backyardnature.net/n/19/190308bm.jpg
In that picture's center, the broadest scale is diagonally broken across it's middle. This is a "divided anal plate," as opposed to the "undivided" kind found in many snake groups. The snake's anus is below this anal plate.
In the end I was glad to have pictures of all these details because they were needed. In Jonathan Campbell's Amphibians and Reptiles of Northern Guatemala, the Yucatán, and Belize, none of the photographs looked exactly like ours. At first I thought we had a Bird-eating Treesnake, but that species' anal scales are undivided. It wasn't a Common Tropical Ratsnake because its labial scales were all wrong. Only with Campbell's technical key could I figure it out, mostly noting scale configuration.
This is SYMPHIMUS MAYAE, which most English-speaking literature seems to called the Yucatan White-lipped Snake, though an important article in the Journal of Zoology calls it the Yucatan Cricket-eating Snake, and in Jonathan Campbell's book it's the Mayan Golden-backed Snake. I'd disqualified Campbell's picture of the species because it showed a snake with distinct dark lines running along its length and the snake's "lips" were pure white, while ours are yellow. Coloration can lie, but not the scale patterns. We simply have a yellow-lipped Yucatan White-lipped Snake.
All the English names include the word Yucatan because the species is endemic only to the Yucatan Peninsula, northern Belize and northern Guatemala. Campbell describes it as little-known, but it's not regarded as endangered.
A special feature of Symphimus mayae is that it feeds almost exclusively on insects in the Order Homoptera, which includes grasshoppers, crickets, mantids, stick insects and katydids. In the garden we have plenty of those, especially because I water it, making it an oasis of greenery during our current dry season when most of the landscape is turning brown and gray.
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AFRICAN FOXTAIL GRASS
Last Sunday as I biked between the rancho and Temozón, at the road's edge a certain attractive, knee-high grass leaned over the pavement, as shown at https://www.backyardnature.net/n/19/190308cc.jpg
It looked like one of several species of commonly occurring foxtail grass, genus Setaria, but it was unlike any I'd seen. I figured I'd better photograph its main field marks. The flowering head is shown closer up at https://www.backyardnature.net/n/19/190308cd.jpg
A close-up of a spikelet cluster arising from a very hairy rachis is shown at https://www.backyardnature.net/n/19/190308ce.jpg
In that picture, the long, fuzzy, white items in the image's center are pollen collecting stigmas. Also, note that each cluster consists of more than one spikelet, the spikelets on short stems of different lengths. And at the bases of each cluster, several long, stiff, hair-like bristles arise. Later, at the hut, I photographed a cluster of three spikelets better showing how the bristles arise at the base, shown at https://www.backyardnature.net/n/19/190308ci.jpg
This grass species occurred only in one spot along the highway, but there numerous plants in different states of maturity were evident. One plant had lost most of its spikelets, leaving a hairy rachis behind on which only a few tufts of bristles remained, as shown at https://www.backyardnature.net/n/19/190308cf.jpg
The grass's leaf blades bore long, soft hairs on their upper surfaces, shown at https://www.backyardnature.net/n/19/190308ch.jpg
Finally, you can see what the ligule looked like where the blade connected with the stem at https://www.backyardnature.net/n/19/190308cg.jpg
This grass turned out to be CENCHRUS CILIARIS, bearing many names in English and other languages. The name seeming most appropriate to me is African Foxtail Grass, because it's native to Africa as well as tropical Eurasia, and looks so much like Foxtail Grass. It's naturalized in much of the rest of the world's tropics and semitropics, spread so widely because it makes good permanent livestock pastures in semi-arid places, plus hay and silage can be produced from it.
I was surprised that this was a member of the genus Cenchrus, because that's the Sandbur genus, sandburs being those grasses producing flowers and fruits encased in pea-sized, hard-spined cases forming burrs that can severely puncture a foot or an animal's mouth. Once those burrs are stuck into you, they're hard and painful to remove. You can see a close-up of such a spiny burr, on a Cenchrus spinifex encountered on the Yucatan's northern coast, at https://www.backyardnature.net/n/13/131027sa.jpg
For many years botanists didn't recognize our Cenchrus ciliaris as a sandbur, calling it Pennisetum ciliare. However, now with genetic sequencing, it's understood that the bristles at the spikelet cluster bases of Cenchrus ciliaris are strongly analogous to spines on other Cenchrus species.
It took awhile to be convinced that this was really Cenchrus ciliaris, because details of our spikelet clusters differed in small ways from features seen in pictures on the Internet. Especially, in most clusters of our plants, the inner bristles may be conspicuously widened at their bases on one or two bristles, while in most pictures on the Internet several bristles spread very broadly. Also, most clusters on the Internet are a bit purplish while ours a "straw colored." However, the species is recognized as being very variable, or "polymorphic," over its very wide distribution area, and I can't find any other species it could be.
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CF. GOLDMANELLA?
A month ago at the weedy edge of the abandoned papaya field below the hut a chest-high member of the enormous Composite or Aster Family, the Asteraceae, was prettily flowering with yellow blossoms, as shown at https://www.backyardnature.net/n/19/190308gd.jpg
The composite flower clusters were a little unusual in that the crammed-together, cylindrical disc flowers forming the flower heads' eyes were bright yellow, while the petal-like ray flowers along the heads' margins were somewhat paler, as shown at https://www.backyardnature.net/n/19/190308ge.jpg
Another slightly unusual feature was that each flowering head arose at the tip of an exceptionally long stem, or peduncle, more easily seen in clusters where the heads already have lost their ray flower corollas, as at https://www.backyardnature.net/n/19/190308gf.jpg
A close-up of a composite head appears at https://www.backyardnature.net/n/19/190308gg.jpg
In that picture notice how each ray flower is "pleated" lengthwise, and that ray-flower corolla tips are indented so that a middle "tooth" is a little shorter than the teeth beside it. In the eye's center, the disc flowers' corollas bear lobes that are unusually long, sharp pointed, and backward curving. The greenish involucres subtending the heads were formed of unusual bracts, most noticeable on older heads, as seen at https://www.backyardnature.net/n/19/190308gh.jpg
The bracts, overlapping one another in three or four series, are uncommonly broad and rounded at their tips, instead of being of the usual narrow, long, sharp-tipped type. Also, the bracts are strangely smooth and shiny, with gland-like swellings below their tips. Breaking open a maturing head, we see what's shown at https://www.backyardnature.net/n/19/190308gi.jpg
Important to notice here is that papery "paleae" almost completely, but not entirely wrap around the dark, short-hairy, cypsela-type fruits, and that atop the cypselae there are long, slender, stiff scales or bristles forming "pappuses." Once the fruits mature, the dried-up involucre below each head opens broadly, releasing the cypselae, whose pappus scales now have enlarged and spread apart forming conspicuous star-like "parachutes" useful for wind dissemination, as seen at https://www.backyardnature.net/n/19/190308gj.jpg
The spreading pappus scales atop their dark cypselae are better shown at https://www.backyardnature.net/n/19/190308gk.jpg
And the hairy mature cypselae ready to fly are shown at https://www.backyardnature.net/n/19/190308gl.jpg
With all these excellent field marks noticed, I'm still not sure of this plant's identity. I'd like to think that I'm providing new information on a species endemic to the Yucatan Peninsula, Belize and northern Guatemala, and that it's name is Goldmanella sarmentosa. If you click on the Ver imágenes link at CICY's Flora de la Península de Yucatán page for Goldmanella sarmentosa, you'll see pictures of flowers and leaves looking just like ours. Except that our plants nearly always bear leaves opposite one another on the stems, while leaves on CICY plants alternate with one another. The few descriptions of the plant I've seen say the leaves are alternate.
However, the CICY pictures look as if they're taken of a well watered plant possibly grown in a shaded garden, while mine are struggling in a sunny, dry field. I've seen fast-growing, shaded plants produce alternate leaves when under harsher conditions they're opposite. Also, I've seen descriptions of rarely documented plants described from dried herbarium specimens showing just one growth form copied from one publication by another.
Also, Paul Standley, an early botanical pioneer in this part of the world, described the cypselae's pappuses as consisting of 2-4 very short, stout awns, while our cypselae bear numerous scales that are not very short. However, the only technical drawing I can find of the species shows a hairless cypsela with no pappus at all, suggesting some confusion among the experts.
So, I'm filing our information and pictures under "cf. Goldmanella sarmentosa," cf. being the technical way of saying "I think this may be Goldmanella sarmentosa, but I'm not sure, and any help would be appreciated."
Resorting to this clumsy way of doing things is a little embarrassing, but this is simply a part of the world where lots of organisms still haven't been adequately documented, or documented at all. Maybe our information will help clarify matters.
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TROPICAL MISTLETOE FRUITS
On October 5th of last year, beside the entry road to Palenque National Park in Chiapas, Mexico's southernmost state, a bushy cluster of mistletoe grew so low in a tree that I could touch it. It was obviously a mistletoe because it bore fleshy, green leaves, and issued roots into a tree limb's wood. However, recognizing something as a member of the Mistletoe Family, the Loranthaceae, is just the beginning, because several kinds exist. In the Yucatan Peninsula north of Chiapas, ten species in four genera are listed, and Chiapas, being rainier and having a more diverse topography, probably harbors more.
Our Palenque mistletoe was fruiting, as you can see at https://www.backyardnature.net/n/19/190308st.jpg
In that picture note that the fruit clusters arise from leaf axils, not at the tips of branches. That feature alone disqualifies one of the four genera, but it's a commonly occurring one. Also notice that the leaves are fairly large and almost round. A close-up of some maturing fruits on their unusually thick, woody stems is at https://www.backyardnature.net/n/19/190308su.jpg
Notice that the green stem is sharply angled in cross section. The fruits, when a top is bitten off, reveal a solitary seed inside, and the injured flesh bleeds copious milky latex, as seen at https://www.backyardnature.net/n/19/190308sv.jpg
By comparing these features with online images of all the mistletoe species listed for Chiapas, this species reveals itself as STRUTHANTHUS ORBICULARIS, occurring from southern Mexico south through Central America, well into South America.
In some places English speakers have taken to calling Struthanthus orbicularis the God Bush or God Almighty Bush, and one wonders why. It's true that it's used variously in traditional medicine, though its cures are of the common sort. In Messages from the Gods: A Guide to the Useful Plants of Belize, by Michael Balick and Rosita Arvigo -- partly available online at Google Books -- it's reported to cure headaches and to lower blood pressure.
The Maya often regard two similar plant species to be the males and females of just one species, the female normally being smaller than the male. Balick and Arvigo report that the Maya in Belize regard our Struthanthus orbicularis with its fairly large leaves and long-dangling stems as the male of a species in which the female is Psittacanthus mayanus, which we profile at https://www.backyardnature.net/yucatan/psittaca.htm
That "female" species produces a more compact but smaller bush than our "male" Struthanthus orbicularis, though its red flowers are much more eye-catching than the greenish or greenish-yellow flowers of our "male," which are only about 7mm long (¼in). This pairing sort of makes sense if you're into sexual stereotypes.
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FILTER BUBBLES
In last month's February 2nd issue of The Economist, bestowed on me by visiting tourists, in an article on Facebook the term "filter bubbles" was used. In the context of Facebook and other social media, filter bubbles occur when people see their preconceptions reinforced online. This may happen, for example, when websites provide ads and news based on the user's demographics or browsing history, or a person listens to news only from right- or left-leaning outlets.
I'm glad to have the term filter bubble for two reasons. First, nowadays Facebook-like filter bubbles pop up everywhere, and the filters used are sophisticated. When I had a Facebook page, though I never revealed where I was, how old or what sex I was, I saw plenty of ads for "beautiful Latin women seeking relationships with foreign men."
The second reason I'm glad to have the term is that in Nature many kinds of filter bubbles are profoundly important. Since humans are natural, and so is human thought, when filter bubbles occur among humans, they should be taken seriously. Here's how a certain kind of filter bubble might function in Nature:
Imagine a mountain range whose upper slopes are mantled with a certain wildflower species. As centuries pass, the region's climate grows more arid, so the mountain slopes on which the wildflower live constitute a filter bubble in which some measure of rainfall is being "filtered" out. From Nature's perspective, filter bubbles are parts of an ecosystem in which some expected, required feature is being limited. The wildflowers evolved expecting a certain amount of rainfall, and now that rainfall is diminishing.
The wildflower population survives by gradually shifting its numbers into the valley, where there's less drying-out exposure to wind and intense high-elevation sunlight. However, some individual wildflowers find refuge in the milder, moister microclimates at sheltered bases of large boulders, so they stay high up.
Over time, if the drying trend continues, the distance between the valley plants and those remaining by boulders high up becomes so great that pollinators no longer can transfer pollen between the two populations. The two populations became genetically isolated from one another. Gradually the two populations evolve along their own paths, each developing adaptations enhancing their chances for survival in their own environment, but not the other's -- for example, those above endure colder nights, shorter growing season, more UV radiation, etc. If this divergent evolution lasts long enough, the two populations develop into separate species.
So, filter bubbles, by introducing changes from the norm, cause stress in communities, often over time resulting in the communities' breakup. This happens whether among wildflowers, bacteria or humans.
Among humans, when a Facebook-type or news-outlet filter bubble gives the impression that a large percentage of people think or feel a certain way, it may or may not be true. Distortions of fact can be recognized by some people, but not by others. Today's false news inevitably produces two groups accusing one another of lying, and society is stressed and fragmented no less than if it were a wildflower population in a changing climate.
The false news filter bubble is a powerful tool for vested interests manipulating parts of society. If that bubble endures, like wildflowers with their diminishing rainfall, we humans with our growing confusion about who has the true facts may be headed toward our own special desert.
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Best wishes to all Newsletter readers,
Jim
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