Dendrobranchiata

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Dendrobranchiata
Penaeus monodon

Penaeus monodon

Systematics
Over trunk : Molting animals (Ecdysozoa)
Trunk : Arthropod (arthropoda)
Sub-stem : Crustaceans (Crustacea)
Class : Higher crabs (Malacostraca)
Order : Decapods (decapoda)
Subordination : Dendrobranchiata
Scientific name
Dendrobranchiata
Bate , 1888

The Dendrobranchiata form a suborder of the decapod crabs . It comprises around 500 species, including some economically important farmed shrimp .

description

As with all decapods, the laterally flattened body is divided into the two tagmata cephalothorax and abdomen . The carapace covering the cephalothorax is an important distinguishing feature of the families within the dendrobranchiata. For example, the carapace in the Solenoceridae family has a thorn just behind the stalked eyes, which is unique in this subordination. At the front, the carapace ends in the so-called rostrum, which can have very variable lengths within this subordination.

In most cases, the abdomen is longer or about the same length as the cephalothorax. The pleura (lateral processes) of the second segment ( somits ) do not overlap those of the first. This distinguishes the species of the Dendrobranchiata from the shrimp of the Caridea .

The Dendrobranchiata have scissors on the first three striding legs (pereiopods). Exopodites are absent (Sicyoniidae, Sergestidae, Luciferidae), are reduced ( Hymenopenaeus sp.), Or are present. The swimming legs ( pleopods ) are one-membered in the Sicyoniidae family, two-membered in the remaining families. The rearmost pair of swimming legs, formed into uropods, has no diaeresis in contrast to many other decapods .

Characteristic of the Dendrobranchiata are the eponymous gills, which are branched like a tree (Greek "dendro" tree, "branchia" gills).

Reproduction and life cycle

The mating usually takes place after a molt of the female, at night or at sunset. Courtship and mating can last up to three hours. Spawning also occurs at night, once in a molting cycle or several times. With the exception of the Luciferidae, the females do not care for the brood , the eggs are shed directly.

Already in the first 24 hours the nauplii hatch , which, in contrast to the sister group of the pleocyemata, are free-swimming. They cannot eat and go through 5 to 8 nauplius stages in 68 hours. These end when the first two maxillipedas and a carapace have developed and the telson becomes bipartite. Over the following 5 to 6 Zoea stages, the larva finally develops into what is known as the post-larva, which for the first time moves by means of swimming legs. At this stage, the scissors on the first three pairs of legs also become functional for the first time. Adolescence is reached via a few more moults .

distribution and habitat

The Dendrobranchiata are widespread worldwide at sea depths of 200 to 2000 meters; mainly between latitudes 40 ° N and 40 ° S. Some species of the Sergestidae live in fresh water.

With the exception of the planktonic Luciferidae, the Dendrobranchiata are benthic creatures . They are omnivorous . Thus, as arrow worms , ostracods , copepods , various mollusks and detritus eaten.

Systematics

The Dendrobranchiata are divided into two superfamilies and seven recent families:

swell

  • Carolina Tavares and Joel W. Martin: Suborder Dendrobranchiata Bate, 1888 . In: FR Schram, JC von Vaupel Klein, J. Forest and M. Charmantier-Daures (eds.): Eucarida: Euphausiacea, Amphionidacea, and Decapoda (partim). Treatise on Zoology - Anatomy, Taxonomy, Biology - The Crustacea . 9A. Brill Publishers, 2010, ISBN 978-90-04-16441-3 , pp. 99–164 ( pdf 2.04Mb [accessed on February 18, 2012]).

Individual evidence

  1. ↑ Sammy De Grave, N. Dean Pentcheff, Shane T. Ahyong et al .: A classification of living and fossil genera of decapod crustaceans . In: Raffles Bulletin of Zoology . Supplement No. 21. 2009, p. 1–109 ( pdf 7.73Mb [accessed February 18, 2012]).

Web links

Commons : Dendrobranchiata  - collection of images, videos and audio files