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Compared to other species of crayfish in its range, L. chimera is a sizable crayfish. On average, adults of this species range from about 9.5 to 11.8 centimeters (or 3.7 to 4.7 inches) in body length, measuring from the anterior tip of the rostrum to the posterior tip of the telson.
Where it projects forward beyond the eyes, this projection is called a rostrum. The carapace is calcified to varying degrees in different crustaceans. [1] Zooplankton within the phylum Crustacea also have a carapace. These include Cladocera, ostracods, and isopods, but isopods only have a developed "cephalic shield" carapace covering the head.
The rostrum narrows anteriorly, appearing slightly pinched in the middle, with ridges typically of a rust-orange color, and marginal spines are present. The claws of this species may get quite large in proportion to body size, they have somewhat prominent tubercles , and there is a relatively significant gap between the fingers of the claws ...
The rostrum is short and in individuals over 50 mm (2.0 in) OCL usually does not reach the base of the third antenna segment. In those measuring 20–140 mm (0.79–5.51 in) OCL the rostrum is to the base or midpoint of that segment and, in some under 20 mm (0.79 in), goes to the end of the third segment. [4]
The Hell Creek Crayfish lacks pigment in its body and does not have eyes. It reaches an overall body length of 2.5 to 3.0 inches. [3] It has a convergent rostrum, which is the beak-like shell located between the crayfish's eyes. [5] Its areola is narrow, and if a cervical spine is present, it is very small.
A shed carapace of a lady crab, part of the hard exoskeleton Body structure of a typical crustacean – krill. The body of a crustacean is composed of segments, which are grouped into three regions: the cephalon or head, [5] the pereon or thorax, [6] and the pleon or abdomen. [7]
It is chiefly differentiated from the other species in the genus Cherax by the form of the rostrum, the shape of the claws and the small size of its eyes. [2] In C. holthuisi, the rostrum has two indentations on each side, and several indistinct lobes; in most other species, there are 3–8 teeth on the rostrum. [2]
The rostrum is short reaching at most the middle of the third segment of the antenna, often only to the base of that segment. The cephalon (head) is generally poorly to moderately spined with relatively few spines, of small size or rounded bumps. Sharp spines sometimes found on smaller specimens.