| from the July 11,, 2010 Newsletter issued from Hacienda
Chichen Resort beside Chichén Itzá Ruins, central Yucatán, MÉXICO MUD TURTLE The Yucatán is a vast, low slab of limestone. Over great periods of time rainwater dissolves limestone so the Yucatán's bedrock is honeycombed with caves and other erosional fissures. In some places caves have collapsed causing sinkholes to form on the surface. Here sinkholes are called cenotes (se-NO-tehs). In the arid north and somewhat less arid central Yucatán, rainwater is drained away by subterranean rivers. In fact, except where sinkholes are deep enough to dip below the groundwater level, forming circular, very swimmable pools, in the Yucatán's interior there are no rivers, streams, lakes or ponds. Therefore, imagine my delight the other day when as I sat in my hut's door watching the end of an afternoon rainstorm a Red-cheeked Mud Turtle, KINOSTERNON SCORPIOIDES, wandered right in front of me. It's shown above. Apparently only three turtle species occur in the Yucatán's interior. One of those is the ubiquitous Red-eared Turtle and the other is the Furrowed Wood Turtle, which seems to be fairly rare, maybe because of its fame as good to eat. So, seeing a turtle here that's not a Red-eared (called Mesoamerican Slider by Campbell) is special. And one just wonders where this mud turtle finds his mud. During the dry season he must simply hold up underground in a low-energy, low-water-use state something like hibernation. Campbell says that one of this turtle's most distinctive features is the bright red or orange blotches or spots on the side of it's head. You can see that our turtle hasn't a hint of that, so maybe we're seeing a local Yucatan variation, or an old individual whose colors have faded. Red-cheeked Mud Turtles are distributed all the way from northeastern Mexico through Central America to the Amazonian drainage and northern Argentina, so the species is emblematic of the American Tropics. from the August 21, 2011 Newsletter issued from written
at Mayan Beach Garden Inn
20 kms north of Mahahual, Quintana Roo, México |
| We've seen this species before up at Hacienda Chichen, but that individual
lacked red cheeks. This one's markings were more like those in the books, so maybe it's
more typical. The next day, during a rain, I found a similar one in our compost heap,
apparently enjoying some banana peelings. These sightings call to mind a recent study that looked at the genetic diversity of River Turtles, Dermatemys mawii, distributed throughout the Maya area. Researchers had assumed that there'd be great diversity, since the populations were isolated from one another because of the lack of surface rivers in the Yucatán, and mountain ranges between populations elsewhere. They found just the opposite -- remarkable genetic sameness. The most logical explanation is that the ancient Maya cultivated River Turtles, carrying them from pond to pond, enabling frequent gene flow leading to genetic homogeneity. That study is available here. from the October 9, 2011 Newsletter issued from written
at Mayan Beach Garden Inn
20 kms north of Mahahual, Quintana Roo, México
That picture very nicely shows four tiny, fingerlike, fleshy projections dangling from the turtle's throat area. Those are "barbels," which occur on many species of fish and turtles. A catfish's whiskers are barbels. When identifying fish and turtles, often the number and placement of barbels serve as good field marks. You can imagine that barbels provide some kind of touch guidance as the turtle forages atop the mud in dark, muddy water, but it seems that they're capable of much more than that. Turtle barbels contain olfactory nerve endings, which means that the barbles are used for smelling. Turtles on dry land can smell odors as we do, but in water turtles with such barbels have this extra odor-sensing method. As the turtle scoots its chin atop submerged mud, through its barbels it's smelling what passes below it. |
