Kingdom: Animalia
Phylum: Arthropoda
Class: Maxillopoda
Maxillopoda includes a diversity of crustaceans, more specifically barnacles, copepods and related animals. As you can see, the animals in this class are generally smaller with shortened bodies and reduced abdomens that lack appendages. This has caused a suggestion in which the ancestors of maxillopods have developed sexual maturity before it's complete morphication, thus explaining the size of these crustaceans. Keep in mind that the Maxillopoda class is often described as controversial as phylogeny is subject to change when orders and lower classifications are further studied.
Orders within the Maxillopoda class include:
1. ARGULOIDA:
A group of crustaceans in the order has been known as the fish lice. They are parasitic on freshwater fish and essentially what they do is latch on their hosts' tongue, consume it and occupy it. Therefore, when the fish open their mouth for the entry of food, the parasites consume whatever comes in. The fish will die from the lack of nutrients. Examples of crustaceans within the Arguloida Order:
Phylum: Arthropoda
Class: Maxillopoda
Maxillopoda includes a diversity of crustaceans, more specifically barnacles, copepods and related animals. As you can see, the animals in this class are generally smaller with shortened bodies and reduced abdomens that lack appendages. This has caused a suggestion in which the ancestors of maxillopods have developed sexual maturity before it's complete morphication, thus explaining the size of these crustaceans. Keep in mind that the Maxillopoda class is often described as controversial as phylogeny is subject to change when orders and lower classifications are further studied.
Orders within the Maxillopoda class include:
1. ARGULOIDA:
A group of crustaceans in the order has been known as the fish lice. They are parasitic on freshwater fish and essentially what they do is latch on their hosts' tongue, consume it and occupy it. Therefore, when the fish open their mouth for the entry of food, the parasites consume whatever comes in. The fish will die from the lack of nutrients. Examples of crustaceans within the Arguloida Order:
2. CALANOIDA:
For this particular order, the crustaceans are solely copepods, a kind of zooplankton. They can be found in many of the world's oceans, consisting 55%-95% of plankton samples. Both marine and freshwater copepods include around 40 families with about 1800 species. They are crucial in food webs as many higher trophic level predators rely on them for diet as well as growth. Baleen whales are greatly dependent of copepods. Calanoids can easily be differentiated from other planktons as their antennas are twice the length of their body combined. Another key fact is that there is an evident joint between the fifth and the sixth body segments. Examples of copepods within the Calanoida Order:
3. CYCLOPOIDA
Similar to the Calanoida Order, Cyclopoids include many small copepods that live in both salt and freshwater habitats. Some key features are their rapid movement as well as their metamorphic larval development. Contrary to Calanoids, Cycloids are distinguished by having their antennas shorter than the length of the head and the thorax, and joint lies between the fourth and the fifth segments of the body. Examples of copepods within the Cyclopoida Order:
4. HARPACTICOIDA
Another order or copepods under the class Maxillopoda, this group composes of approximately 3,000 species. Harpacticoids are common inhabitants of sea ice in the Arctic and Antarctic Seas. Their members are benthic copepods which are found everywhere in the world in the marine environment. To distinguish them, notice their very short antennas and a wide abdomen with a worm-like body. Like Cyclopoids, they have a major join located between the fourth and the fifth segments of the body. Examples of copepods within the Harpacticoida Order:
5. MISOPHRIOIDA
A copepod order of free-living crustaceans which consists of only 34 species in 16 genera and 3 families. Due to small amounts of species, research go as far as only how they appear visually and what features they carry. Misophrioids have carapace-like extension which starts from the head down the first segment of the body. Some have been even noted to have no eyes, however that is not hundred percent confirmed. Examples of copepods within the Misophrioida Order:
6. MONSTRILLOIDA
Despite it's vicious name, like all other orders, the copepods within this group are nonetheless small. This class contains only one order, Monstrillidae, thus research on this class is minimal. So far, researchers have been able to grab a hold of the fact that Monstrilloids have a life cycle that differs from all other copepods. The larvae, in other words their initial form, are parasites, while adults are platonic, functioning solely for reproduction. They have a well-developed fourth pair of swimming legs in absence of the fifth pair. Females carry a long pair of spines which eggs are attached, while males have a genital protuberance. Examples of copepods within the Monstrilloida Order:
7. MORMONILLOIDA
This class has only 5 known species in two genera of only one family, Mormonillidae. Crustaceans of this kind have antennule that 3 or 4 segments long. Another note is their evident setae which are basically stiff bristles that allow easier attachment. Their fifth pair of swimming legs are absent, but nonetheless they are marine creatures. Examples of crustaceans within the Mormonilloida Order:
8. MYSTACOCARIDA
Mystacocarids are tiny crustaceans that are all less than 1mm long , located on sand grains between tide marks. In other words, they can be found on intertidal beaches. There are currently only 13 researched species in two genera. Mystacocarids are described to have a cylindrical body with 5 thoracic and 5 abdominal segments. Their heads are relatively large with a narrow duct that divided them into two. As compared to the previous crustaceans and copepods, Mystacocarids are quite different in terms of visual appearance. Examples of crustaceans within the Mystacocarida Order:
Mystacocarids are tiny crustaceans that are all less than 1mm long , located on sand grains between tide marks. In other words, they can be found on intertidal beaches. There are currently only 13 researched species in two genera. Mystacocarids are described to have a cylindrical body with 5 thoracic and 5 abdominal segments. Their heads are relatively large with a narrow duct that divided them into two. As compared to the previous crustaceans and copepods, Mystacocarids are quite different in terms of visual appearance. Examples of crustaceans within the Mystacocarida Order:
9. PEDUNCULATA
In the Pedunculata Order, the organisms are barnacles, filter-feeding crustaceans, which live attached to hard surfaces such as rock in the intertidal zone on beaches. This class is commonly known for it's Goose Barnacles as they are found in large clumps. Most importantly in some places, Goose Barnacles are harvested as food.
10. PLATYCOPIOIDA
This order is relatively small as there are only 8 species with 4 genera in the family of Platycopiidae. As you can see in the image on the right, Platycopioids as such have a wide body, shaped almost cylindrical, with attenules. Reseach on this order is insufficient.
This order is relatively small as there are only 8 species with 4 genera in the family of Platycopiidae. As you can see in the image on the right, Platycopioids as such have a wide body, shaped almost cylindrical, with attenules. Reseach on this order is insufficient.
11. POECILOSTOMATOIDA
Poecilostomatoids which are copepods, have been classified heavily based on the structure of the mouth. The mouth is represented with a transverse slit. They have antennules with antennas that shaped as hooks utilized for attachment on hosts, thus making them ectoparasites. Similar to Monstilloids and other crustaceans, Poecilostomatoids have immature forms during their larval development, and they differ from their adulthood. These copepods carry embryos in either paired or single egg sacs, located attached on the first segment of their bodies. Examples of copepods within the Poecilostomatoida Order:
Poecilostomatoids which are copepods, have been classified heavily based on the structure of the mouth. The mouth is represented with a transverse slit. They have antennules with antennas that shaped as hooks utilized for attachment on hosts, thus making them ectoparasites. Similar to Monstilloids and other crustaceans, Poecilostomatoids have immature forms during their larval development, and they differ from their adulthood. These copepods carry embryos in either paired or single egg sacs, located attached on the first segment of their bodies. Examples of copepods within the Poecilostomatoida Order:
12. SIPHONOSTOMATOIDA
The copepods in the Siphonostomatoida Order compose 75% of all other copepods that parasitize on fish. Their great success has been suggested by their possession of siphon-like mandibles and a frontal filament to help attachment to their hosts. There are 39 acknowledge families which most are marine with an exception of a few that live in freshwater. Examples of copepods within the Siphonostomatoida Order:
Learn more about the phylogenetic tree and how classes such as the Maxillopoda as well as the other taxonomy levels play prominent roles! Refer to the videos below for more info!
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