'The ''Mesothelae''' include the only recent family [[Liphistiidae]]. Two more families ([[Arthrolycosidae]] and [[Arthromygalidae]]) are recognized from fossil evidence only.
The Liphistiidae are burrowing spiders only found in [[Southeast Asia]], [[China]], and [[Japan]] with about 90 species in 5 genera. Spiders of this remnant suborder are very rare, and are among the most "[[primitive (biology)|primitive]]" types of spiders in existence.
The '''Mygalomorphae''' are also called the ''Orthognatha'', referring to the orientation of the [[Cheliceral fang|fang]]s which point straight down and do not cross each other (cf [[Araneomorphae]]). This suborder includes the heavy bodied, stout legged spiders popularly known as [[tarantula]]s as well as the dangerous [[Australasian funnel-web spider]]s. They have ample [[poison]] glands that lie entirely within their [[chelicerae]]. Their chelicerae and fangs are large and powerful. Occasionally members of this suborder will even kill small [[fish]], small [[mammal]]s, etc. Most members of this suborder occur in the [[tropics]] and [[subtropics]], but their range can extend farther toward the poles, e.g. into the southern and western regions of the [[United States]] and [[Canada]], the northern parts of Europe and south into [[Argentina]] and [[Chile]].
