Search results
Results from the WOW.Com Content Network
In most arachnids, the retina probably does not have enough light sensitive cells to allow the eyes to form a proper image. [22] In addition to the eyes, almost all arachnids have two other types of sensory organs. The most important to most arachnids are the fine sensory hairs that cover the body and give the animal its sense of touch.
The microscopic mite Lorryia formosa (). The mites are not a defined taxon, but is used for two distinct groups of arachnids, the Acariformes and the Parasitiformes.The phylogeny of the Acari has been relatively little studied, but molecular information from ribosomal DNA is being extensively used to understand relationships between groups.
The epithelial cells of the midgut are often infected by rickettsia-like parasites, like in some other arachnids. Resorptive cells, which may be unique to harvestmen, contain lipid droplets, glycogen and mineral spherites. These spherites are also common in many arachnids. They seem to function in heavy metal excretion and mineral storage.
Basic characteristics of arachnids include four pairs of legs (1) and a body divided into two segments: the cephalothorax (2) and the abdomen (3). The ventral side of a brown widow spider. The epigastric plates and furrow are visible, as well as the hourglass marking on the underside of the abdomen, which is a characteristic feature of widow ...
2.3 Class Arachnida (Arachnids) 2.4 Class Pycnogonida. ... 4.10 Class Malacostraca (Malcostracans, such as crabs and lobsters) 4.10.1 Subclass Eumalacostraca.
The Burgess shale animals like Sidneyia from about have been classified as chelicerates, the latter because its appendages resemble those of the Xiphosura (horseshoe crabs). However, cladistic analyses that consider wider ranges of characteristics place neither as chelicerates.
The Malpighian tubule system is a type of excretory and osmoregulatory system found in some insects, myriapods, arachnids and tardigrades. It has also been described in some crustacean species, [ 1 ] and is likely the same organ as the posterior caeca which has been described in crustaceans.
Arachnids by classification; Subcategories. This category has the following 11 subcategories, out of 11 total. A. Acari (6 C, 102 P) Amblypygi (38 P) H. Harvestmen (7 ...