A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat regions covered with wind-swept sand or dunes with little or no vegetation are called ergs or sand seas. Dunes occur in different shapes and sizes, but most kinds of dunes are longer on the stoss (upflow) side, where the sand is pushed up the dune, and have a shorter slip face in the lee side. The valley or trough between dunes is called a dune slack.
Arachnida is a class of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, harvestmen, camel spiders, whip spiders and vinegaroons.
The Opiliones are an order of arachnids colloquially known as harvestmen, harvesters, harvest spiders, or daddy longlegs. As of April 2017, over 6,650 species of harvestmen have been discovered worldwide, although the total number of extant species may exceed 10,000. The order Opiliones includes five suborders: Cyphophthalmi, Eupnoi, Dyspnoi, Laniatores, and Tetrophthalmi, which were named in 2014.
Huntsman spiders, members of the family Sparassidae, are known by this name because of their speed and mode of hunting. They are also called giant crab spiders because of their size and appearance. Larger species sometimes are referred to as wood spiders, because of their preference for woody places. In southern Africa the genus Palystes are known as rain spiders or lizard-eating spiders. Commonly, they are confused with baboon spiders from the Mygalomorphae infraorder, which are not closely related.
The Pholcidae are a family of araneomorph spiders. The family contains over 1,800 individual species of pholcids, including those commonly known as cellar spider, daddy long-legs spider, carpenter spider, daddy long-legger, vibrating spider, gyrating spider, long daddy, and skull spider. The family, first described by Carl Ludwig Koch in 1850, is divided into 94 genera.
Solifugae is an order of animals in the class Arachnida known variously as camel spiders, wind scorpions, sun spiders, or solifuges. The order includes more than 1,000 described species in about 147 genera. Despite the common names, they are neither true scorpions, nor true spiders, nor camels. Most species of Solifugae live in dry climates and feed opportunistically on ground-dwelling arthropods and other small animals. The largest species grow to a length of 12–15 cm (5–6 in), including legs. A number of urban legends exaggerate the size and speed of the Solifugae, and their potential danger to humans, which is negligible.
Leucorchestris arenicola, commonly called the dancing white lady spider, is a huntsman spider in the family Sparassidae and genus Leucorchestris. It is commonly found in the Namib desert of Namibia. It is often mistaken with the similarly named Carparachne aureoflava, or more commonly known as the wheel spider from the same location. L. arenicola relies on seismic vibrations, called drumming, for communication. It taps its foremost legs on the sand to send messages to other white lady spiders. Male L. arenicola will travel over 50 m in one night searching for a mate. If they find a mate, they must be extremely careful, for drumming the wrong message can be deadly. One of the major features that characterizes its nocturnal behavior is its specialized vision, using eight eyes in different orientations to capture a panoramic view of the surroundings. L. arenicola spiders use temporal summation in order to be able to see dim lighting during night-time wanderings. The species was first described by Reginald Frederick Lawrence in 1962, who described all the species in the genus Leucorchestris.
Animal locomotion, in ethology, is any of a variety of methods that animals use to move from one place to another. Some modes of locomotion are (initially) self-propelled, e.g., running, swimming, jumping, flying, hopping, soaring and gliding. There are also many animal species that depend on their environment for transportation, a type of mobility called passive locomotion, e.g., sailing, kiting (spiders), rolling or riding other animals (phoresis).
Robot locomotion is the collective name for the various methods that robots use to transport themselves from place to place.
Scincus scincus, also commonly known as the sandfish skink, common sandfish or common skink, is a species of skink notable for its burrowing or swimming behaviour in sand. It is native to the Sahara Desert and the Arabian Peninsula, but is also kept as a pet elsewhere.
The Algodones Dunes is a large sand dune field, or erg, located in the southeastern portion of the U.S. state of California, near the border with Arizona and the Mexican state of Baja California. The field is approximately 45 miles (72 km) long by 6 miles (9.7 km) wide and extends along a northwest-southeast line that correlates to the prevailing northerly and westerly wind directions. The name "Algodones Dunes" refers to the entire geographic feature, while the administrative designation for that portion managed by the Bureau of Land Management is the Imperial Sand Dunes Recreation Area. In 1966, Imperial Sand Hills was designated as a National Natural Landmark by the National Park Service. The Algodones Dunes are split into many different sections. These sections include Glamis, Gordon's Well, Buttercup, Midway, and Patton's Valley. Although the Arabic-derived Spanish word algodones translates to "cotton plants", the origin of the toponym is unknown.
Terrestrial locomotion has evolved as animals adapted from aquatic to terrestrial environments. Locomotion on land raises different problems than that in water, with reduced friction being replaced by the increased effects of gravity.
Leucorchestris is a genus of African huntsman spiders that was first described in 1962 by R. F. Lawrence, who described all of the species in the genus between 1962 and 1966.
Ingo Rechenberg was a German researcher and professor in the field of bionics. Rechenberg was a pioneer of the fields of evolutionary computation and artificial evolution. In the 1960s and 1970s he invented a highly influential set of optimization methods known as evolution strategies. His group successfully applied the new algorithms to challenging problems such as aerodynamic wing design. These were the first serious technical applications of artificial evolution, an important subset of the still growing field of bionics.
Eusparassus is a genus of huntsman spiders, known as the stone huntsman spiders, it was first described by Eugène Louis Simon in 1903.
Carparachne is a genus of Namibian huntsman spiders that was first described by R. F. Lawrence in 1962. As of September 2019 it contains two species, found in Namibia: C. alba and C. aureoflava. The golden wheel spider uses cartwheeling to move across hot, sandy ground, similar to the related Cebrennus rechenbergi, which uses a flic-flac motion.
Cebrennus is a genus of huntsman spiders that was first described by Eugène Louis Simon in 1880. It is considered a senior synonym of Cerbalopsis.
Arthropods, including insects and spiders, make use of smooth adhesive pads as well as hairy pads for climbing and locomotion along non-horizontal surfaces. Both types of pads in insects make use of liquid secretions and are considered 'wet'. Dry adhesive mechanisms primarily rely on Van der Waals' forces and are also used by organisms other than insects. The fluid provides capillary and viscous adhesion and appears to be present in all insect adhesive pads. Little is known about the chemical properties of the adhesive fluids and the ultrastructure of the fluid-producing cells is currently not extensively studied. Additionally, both hairy and smooth types of adhesion have evolved separately numerous times in insects. Few comparative studies between the two types of adhesion mechanisms have been done and there is a lack of information regarding the forces that can be supported by these systems in insects. Additionally, tree frogs and some mammals such as the arboreal possum and bats also make use of smooth adhesive pads. The use of adhesive pads for locomotion across non-horizontal surfaces is a trait that evolved separately in different species, making it an example of convergent evolution. The power of adhesion allows these organisms to be able to climb on almost any substance.
Arachnid locomotion is the various means by which arachnids walk, run, or jump; they make use of more than muscle contraction, employing additional methods like hydraulic compression. Another adaptation seen especially in larger arachnid variants is inclusion of elastic connective tissues.
