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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 anterior portion of the crayfish is the cephalothorax region. The region rostral to the cephalic groove, which separates the head and thorax region, is characterized by the presence of eyes, antennae and claws while the region caudal contains four pairs of walking legs. This is the crayfish's primary mode of locomotion.
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.
Pontastacus leptodactylus, [2] the Danube crayfish, [3] Galician crayfish, [3] Turkish crayfish [4] or narrow-clawed crayfish, is a relatively large and economically important species of crayfish native to fresh and brackish waters in eastern Europe and western Asia, mainly in the Pontic–Caspian region, among others including the basins of the Black Sea, and the Danube, Dnieper, Don and ...
On segments three to five there is usually one spine in the first line. First line spines are larger and sharper to very sharp on larger individuals, above 40 mm (1.6 in). A second line of spines is generally poorly developed, being absent to tiny in smaller animals, under 30 mm (1.2 in), and tiny to small on larger specimens.
In contrast to the unarmed rostrum of C. parvus, all highland New Guinean species, except C. monticola, have two or more pairs of lateral processes (tubercles or spines) on the rostrum. C. parvus, however, has two well-defined uncalcified patches on the first cheliped of mature males and is clearly allied to the quadricarinatus species-group.
Rostrum (from Latin rostrum, meaning beak) is a term used in anatomy for several kinds of hard, beak-like structures projecting out from the head or mouth of an animal. Despite some visual similarity, many of these are phylogenetically unrelated structures in widely varying species.
Austropotamobius torrentium, also called the stone crayfish, is a European species of freshwater crayfish in the family Astacidae. It is mostly found in tributaries of the Danube , having originated in the northern part of the Balkan Peninsula .