Cave-Dwellers Known Since 1966

In a previous post I declared: "how many of them [cave bugs] are just compatible VARIETIES of their related counterparts that we already know over the surface?"

Next, we will be able to see and to compare more cave dwellers known at least since 1966:



Left: This inch-long troglobitic isopod is a marine relict inhabiting Mexican caves along a former seacoast. Its possible ancestors were ocean-dwellings which invaded fresh-water caves when the ancient coastline retreated. Right: A predatory white spider prowls through the dark interior of a cavern on the Edwards Plateau. Troglobitic spiders usually stalk their prey instead of engaging in the energy-consuming practice of spinning webs.

Left: Blind but mysteriously sensitive to light, a cave-dwelling millipede curls helplessly in the glare of a flashlight beam. As it becomes more fully adapted to life in the cave over the years, it may lose even this feeble response to the intrusion of light into its nighttime world.

Two closely related Texas amphipods, a blind white cave dweller (left) and an eyed surface dweller (right), are each about a quarter of an inch long. Floods carry surface amphipods over wide areas, but cave amphipods tend to be restricted to single cave systems.

This two fresh-water shrimp illustrate a common adaptation of cave animals. The cave species (left) lays only a few large-yolked eggs at a time. Thus the young cave shrimp will be relatively well developed when they have to find food for themselves. The surface species (right) lays many small eggs. Once deposited, the incubating eggs are attached beneath the mother´s body.


Left: The large compound eye of a surface crayfish glints with hundreds of minute lenses. Right: The troglobitic (cave) crayfish has no eyes, only a knoblike supporting stalk. It retains eyestalks since the structures contain several organs not related to vision.

A pale shadow of its surface-dwelling relative, the blind and colorless cave crayfish (left) seems in every way more delicate than its larger surface relative (right). The cave species is slower-moving and able to fast between infrequent meals. It has a slimmer body, more slender legs, and longer antennae than the dark, robust surface dweller.

See also the compatible heterosis on The Crayfish Variation.

Reference:
Mohr, Charles E. & Poulson, Thomas L., 1966, Our living world of nature: “The Life of the Cave”, McGraw-Hill, the World Book Encyclopedia and the U. S. Department of the Interior, 232 p., New York.



And other cave-dwellers:

http://fdocc.blogspot.com/2006/02/adaptations-of-cave-fish.html

http://fdocc.blogspot.com/2006/01/new-27-cave-bugs.html

http://fdocc.blogspot.com/2006/01/laupala-cricket-variation.html

http://fdocc.blogspot.com/2006/02/more-adaptive-comparisons-of-cave.html