Acanthacaris

Acanthacaris tenuimana

Acanthacaris is a meeresbewohnende genus of decapods ( Decapoda ) from the family of lobster -like ( Nephropidae ). It includes two species, Acanthacaris tenuimana and Acanthacaris caeca, which are mainly found in the deep sea. Both species are not fished, despite their relatively large body size.

Description

Acanthacaris achieved body lengths up to 40 cm, the carapace length can be up to 20 cm.

The rostrum of Acanthacaris is mostly pushed laterally and has the back and the belly side, but not lateral teeth. The surface of the carapace and pleon is dotted with many small sharp spines ( spinules ). Also the telson has at its edges on many spines. The eyes of Acanthacaris are greatly reduced and not pigmented, the crabs of this genus are probably blind.

The first pair of legs border the same, the single molded to shear segments are cylindrical and have many small mandrels. The second pair of walking legs is exceptionally long and slender, while the third is much shorter but appears more robust. The Exopoditen the uropods have a full diaeresis, a transverse recess.

Distribution and habitat

The two species of the genus Acanthacaris have separate distribution areas. Acanthacaris caeca is in the Gulf of Mexico, the Caribbean and in Florida, have been found mainly in depths of 550-825 m. Acanthacaris tenuimana is native to the coasts of the Indian Ocean and the western Pacific. This species lives mainly in depths of 600-1670 m. Both types tend to live on soft mud and in self-dug caves.

Systematics and Taxonomy

The genus consists of the following ways:

  • A. Milne -Edwards Acanthacaris caeca, 1881
  • Acanthacaris tenuimana Bate, 1888

The two species can be determined to scissor hand by the ratio of the lengths of scissors finger. In Acanthacaris caeca is this ratio is about 1 in Acanthacaris tenuimana it is significantly larger than 1, the finger scissors are so much longer than the scissor hands in the latter kind.

The genus appears to be a basal taxon within the lobster -like to be, making it sister taxon to the remaining genera of this family. In some Systamtiken the bill is supported by the genus in its own subfamily, the Neophoberinae Glaessner, is set in 1969. Among the characteristic autapomorphies include, among others the morphology of the rostrum and symmetric scissors with narrow, cylindrical shaped scissors palms with needle -shaped denticles on the scissor fingers.

The first description of the genus was made in 1881 by Alphonse Milne -Edwards under the name Phoberus with the type species Phoberus caeca. Charles Spence Bate discovered in the Challenger Expedition and thus before 1881, the second type and named it first Acanthacaris tenuimana. The publication of his description could not take place until 1888, so he took the generic name of Milne -Edwards. However Phoberus is a sub-genre of Erdkäfern ( Trogidae ). Martin Glaessner named the genus in 1969, therefore Neophoberus. As a senior Acanthacaris name is now to be used. Synonyms of the genus are therefore Phoberus A. Milne Edwards, 1881 and Neophoberus Glaessner, 1969, and the misspellings Acanthocaris Bate, 1888 and Phoderus Ramos, 1950.

There are no known fossil record. The once regarded as closely related fossil genus Palaeophoberus Glaessner, 1932 is probably one of the Chilenophoberidae.

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