Cryptolithodes sitchensis
| Cryptolithodes sitchensis | |
|---|---|
 |
|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Malacostraca |
| Order: | Decapoda |
| Infraorder: | Anomura |
| Family: | Lithodidae |
| Genus: | Cryptolithodes |
| Species: | C. sitchensis |
| Binomial name | |
|
Cryptolithodes sitchensis Brandt, 1853 |
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| External identifiers for Cryptolithodes sitchensis | |
|---|---|
| Encyclopedia of Life | 343208 |
| ITIS | 97953 |
| NCBI | 174327 |
| WoRMS | 550616 |
| Also found in: Arctos | |
Cryptolithodes sitchensis, variously known as the umbrella crab, Sitka crab or turtle crab, is a species of lithodid crustacean native to coastal regions of the northeastern Pacific Ocean, ranging from Sitka, Alaska to Point Loma, California. Its carapace extends over its legs such that when it pulls in its legs, it resembles a small stone. It lives in rocky areas from the low intertidal to depths of 17 m (56 ft).
Cryptolithodes sitchensis has a half-moon shaped carapace extending over all of its eight walking legs and two chelipeds, giving them their common names of turtle crab, umbrella crab or helmet crab. The carapace can be 5–10 cm (2.0–3.9 in) at the adult stage and has scalloped edges. This carapace ranges from neutral sandy colors to bright oranges, reds, and purples. The rostrum extends forwards from the carapace, gradually widening before ending abruptly. From above, only the eyes and second antennae are visible. The ventral side is commonly white in color, and the abdomen is protected my multiple hard plates that lack raised margins. The chelipeds are smooth. The fifth pair of walking legs are located at the posterior, and are difficult to distinguish.
C. sitchensis can be found from southern Alaska to southern California. They live within 18 m (59 ft) of the intertidal zone along the exposed coasts of the Pacific Ocean. Intertidal species of Lithodidae prefer habitats of cooler temperatures ranging from 0–25 °C (32–77 °F) and temperatures of 16 °C (61 °F) during larval development. This causes a restriction on their distribution, as water temperatures change due to global warming.
The distinguishing characteristic between C. sitchensis and C. typicus is the rostrum of C. sitchensis is wider distally than proximally, while the opposite is found in C. typicus. Also, C. typicus has raised margins of the abdominal segments, while C. sitchensis does not.
The larvae of C. sitchensis have six tergites at the megalopal stage. Upon reaching the adult stage, the first and second abdominal segments have fused and the sixth tergite and telson are whole. C. sitchensis males and females have symmetrical abdomens, yet females have a greater number of accessory plates on the left side of the third tergite.
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