Dicranopalpus ramosus

Placed in the order of Opiliones, Dicranopalpus ramosus is a long-legged harvestman that appears to be generating a lot of interest in arachnophile circles with numerous internet discussion groups on this creature appearing all over the place. It has a curious and very characteristic position when at rest making it a species easy to identify. It appears to like walls of houses, is quite conspicuous and immediately arouses some curiosity. See previous blog post for a more general description. From experience, once Dicranopalpus ramosus has assumed its resting position it is somewhat reluctant to be disturbed requiring some gentle pursuasion with a soft paint brush to move it along. After which it then assumes the more usual stance of a harvestman that most of us associate with these gangly creatures. This particular specimen measured 3mm in width, 5.6mm long and the longest (2nd pair) of legs each measured 36mm giving a maximum span including the body of 75mm. 

 

Beauty is in the eye of the beholder but it is difficult to see how this creature is ever going to win any points in the beauty stakes. Above are three scanning electron micrographs of an adult female Dicranopalpus ramosus, one of eight found on the same day in early November. Each micrograph clearly shows the pedipalps, used for mating, feeding and that extra pair of hands when needed, the ocularium with its single pair of eyes protruding from the cephalothorax and the chelicerae of which the third segment ends with a pair of toothed pincers. The chelicerae are used for feeding and possibly during the mating process.

The white bar in each of the micrographs above represents 2mm.

 

The micrographs above show (left) epidermis of the cephlothorax (bar = 100um), (centre) the toothed claw at the distal end of the pedipalp (bar = 50um) and (right) the tibia, patella and apophysis of the pedipalp, (bar = 1mm = 1000um). Note the fine hairs covering the apophysis and the inside surface of the tibia. The small white box represents the area shown in the first micrograph below. 


From left to right the above series of micrographs show an increasing magnification of the pedipalp hairs, each area of interest being depicted by the superimposed box. Bars represent 50um, 10um and 2um respectively. It is clear the hairs are complicated structures of a sensory nature.


Above are three further micrographs showing (left), the pedipalp spur, (centre), claw at the end of the first pair of legs and (right), the ocularium. Bar markers represent 200um, 50um and 500um respectively.

 

For anyone with a pair of red/cyan glasses, above are 3D anaglyph portraits of Dicranopalpus ramosus.

 

 


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