Cambarus hamulatus, the prickly cave crayfish,[1][2] is a freshwater crayfish native to Tennessee and Alabama in the United States. It is a cave-dwelling species known from 40 caves across its range.[1][2]
123"Cambarus hamulatus". NatureServe Explorer An online encyclopedia of life. 7.1. NatureServe. Retrieved 10 February 2023.
The Cumberland Plateau extends from Northeastern Kentucky to North Alabama, with a large section of the Plateau spanning East Tennessee and small sections in Georgia. Rocks in this region come primarily from the Pennsylvanian, Mississippian, and Ordovician-Cambrain epochs, meaning the plateau is largely made up of soluble, evaporite rocks such as limestone, gypsum, and dolomite, with a sandstone cap covering the top. This makeup means the area surrounding the plateau is particularly prone to the formation of solution caves. Along the plateau there exists particular hotspots for cave formation: parts of eastern Kentucky, Southeastern Tennessee, and Northern Alabama. The area surrounding Chattanooga, Tennessee --particularly Hamilton, Franklin, Marion, Grundy, and Sequatchie county-- is a major hotspot. Areas surrounding Huntsville and Scottsboro, Alabama are also notable hotspots.
There are a number of species unique to cave environments that can be found in this region, such as blind cave fish, Grey and Indiana Bats (notable examples but there are many other bat species in the region), distinct species of snails, beetles, and crickets, and the subject of this article, the prickly cave crayfish.
It is not the only species of pigment-less, blind Crayfish living in this region, however it is the most notable given its prevalence across roughly 40 different caves. An example of where it can be found is Ship Cave in Little Sequatchie Cove, Sequatchie County, Tennessee. The land on which this cave sits is now privately owned. Public visitation of the property is still allowed, however Insurance prevents any form of caving unless specified by park authorities. The cave itself sits at the bottom of the cove; it is a typical feature of Karst landscapes, being a large solution cave formed by running water at the bottom of the cove.
The crayfish is particularly interesting because it is a prime example of how isolated species in new environments will often undergo significant evolutionary changes. In this case, the crayfish lost its vision and pigment, likely because it no longer had a need for either given the darkness of the cave environment. The crayfish are easy to spot; the water in caves of this region is often crystal-clear, and they are illuminated against the background of darker colored sediment and rocks. One other point of note is that, similar to some cave formations, when put under a blacklight the crayfish glow.
