Diplostraca

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Diplostraca
Temporal range: Jurassic–Present
Vetvistousye rakoobraznye.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Branchiopoda
Subclass: Phyllopoda
Superorder: Diplostraca
Latreille, 1829
Orders [2]
Synonyms [2]
  • Cladocera Latreille, 1829
  • Eucladocera (no evidence for grouping together all other cladocerans as the sister taxon to the monotypic Haplopoda (Leptodora))

The Diplostraca or Cladocera, commonly known as water fleas, is a superorder of small, mostly freshwater crustaceans, most of which feed on microscopic chunks of organic matter, though some forms are predatory. [2]

Contents

Over 1000 species have been recognised so far, with many more undescribed. [2] [3] [4] [5] [6] The oldest fossils of diplostracans date to the Jurassic, though their modern morphology suggests that they originated substantially earlier, during the Paleozoic. Some have also adapted to a life in the ocean, the only members of Branchiopoda to do so, though several anostracans live in hypersaline lakes. [7] Most are 0.2–6.0 mm (0.01–0.24 in) long, with a down-turned head with a single median compound eye, and a carapace covering the apparently unsegmented thorax and abdomen. Most species show cyclical parthenogenesis, where asexual reproduction is occasionally supplemented by sexual reproduction, which produces resting eggs that allow the species to survive harsh conditions and disperse to distant habitats.

Description

Leptodora kindtii is an unusually large diplostracan, at up to 18 mm long. Leptodora.png
Leptodora kindtii is an unusually large diplostracan, at up to 18 mm long.

They are mostly 0.2–6.0 mm (0.01–0.24 in) long, with the exception of Leptodora , which can be up to 18 mm (0.71 in) long. [8] The body is not obviously segmented and bears a folded carapace which covers the thorax and abdomen. [9]

The head is angled downwards, and may be separated from the rest of the body by a "cervical sinus" or notch. [9] It bears a single black compound eye, located on the animal's midline, in all but two genera, and often, a single ocellus is present. [10] The head also bears two pairs of antennae – the first antennae are small, unsegmented appendages, while the second antennae are large, segmented, and branched, with powerful muscles. [9] The first antennae bear olfactory setae, while the second are used for swimming by most species. [10] The pattern of setae on the second antennae is useful for identification. [9] The part of the head which projects in front of the first antennae is known as the rostrum or "beak". [9]

The mouthparts are small, and consist of an unpaired labrum, a pair of mandibles, a pair of maxillae, and an unpaired labium. [9] They are used to eat "organic detritus of all kinds" and bacteria. [9]

The thorax bears five or six pairs of lobed, leaf-like appendages, each with numerous hairs or setae. [9] Carbon dioxide is lost, and oxygen taken up, through the body surface. [9]

Lifecycle

A cladocera giving birth (100x magnification) Rodzaca dafnia.jpg
A cladocera giving birth (100x magnification)

With the exception of a few purely asexual species, the lifecycle of diplostracans is dominated by asexual reproduction, with occasional periods of sexual reproduction; this is known as cyclical parthenogenesis. [11] When conditions are favourable, reproduction occurs by parthenogenesis for several generations, producing only female clones. As the conditions deteriorate, males are produced, and sexual reproduction occurs. This results in the production of long-lasting dormant eggs. These ephippial eggs can be transported over land by wind, and hatch when they reach favourable conditions, allowing many species to have very wide – even cosmopolitan – distributions. [9] Except for the genus Leptodora, which has a metanauplius stage, a nauplius larval stage is absent in Diplostraca. [12]

Evolutionary history

Diplostraca are nested within the clam shrimp, being most closely related to the order Cyclestherida, the only living genus of which is Cyclestheria . Though several fossils from the Paleozoic have been claimed to represent fossils of diplostracans, none of these records can be confirmed. The oldest confirmed records of diplostracans are from the Early Jurassic of Asia. Fossils from the Jurassic are assignable to modern as well as extinct groups, indicating that the initial radiation of the group occurred prior to the beginning of the Jurassic, likely during the late Paleozoic. [13] A Devonian fossil, Ebullitiocaris , is tentatively placed as a diplostracan, however since it is only known from its carapace this is uncertain. [1]

Ecology

Evadne spinifera, one of very few marine diplostracan species Evadne spinifera.jpg
Evadne spinifera , one of very few marine diplostracan species

Most diplostracan species live in fresh water and other inland water bodies, with only eight species being truly oceanic. [10] The marine species are all in the family Podonidae, except for the genus Penilia . [10] Some diplostracans inhabit leaf litter. [14]

Taxonomy

Daphnia magna Daphnia magna.png
Daphnia magna

According to the World Registry of Marine Species, Cladocera is a synonym of the superorder Diplostraca, which is included in the class Branchiopoda. Both names are currently in use. The superorder forms a monophyletic group of 7 orders, about 24 families, and more than 11,000 species. Many more species remain undescribed. [2] [8] The genus Daphnia alone contains around 150 species. [11] Many groups of the water fleas are cryptic species or species flocks. [15]


The following families are recognised: [2]

Superorder Diplostraca Gerstaecker, 1866 (=Cladocera)

Order Anomopoda G.O. Sars, 1865
Family Acantholeberidae Smirnov, 1976
Family Bosminidae Baird, 1845
Family Chydoridae Dybowski & Grochowski, 1894
Family Daphniidae Straus, 1820 [16]
Family Dumontiidae Santos-Flores & Dodson, 2003
Family Eurycercidae Kurz, 1875
Family Gondwanothrichidae Van Damme, Shiel & Dumont, 2007 [17] [18]
Family Ilyocryptidae Smirnov, 1976
Family Macrothricidae Norman & Brady, 1867
Family Moinidae Goulden, 1968
Family Ophryoxidae Smirnov, 1976
Order Ctenopoda G.O. Sars, 1865
Family Holopediidae G.O. Sars, 1865
Family Pseudopenilidae Korovchinsky & Sergeeva, 2008
Family Sididae Baird, 1850
Order Cyclestherida Sars G.O., 1899
Family Cyclestheriidae Sars G.O., 1899
Order Haplopoda G.O. Sars, 1865
Family Leptodoridae Lilljeborg, 1861
Order Laevicaudata Linder, 1945
Family Lynceidae Stebbing, 1902
Order Onychopoda G.O. Sars, 1865
Family Cercopagididae Mordukhai-Boltovskoi, 1968
Family Podonidae Mordukhai-Boltovskoi, 1968
Family Polyphemidae Baird, 1845
Order Spinicaudata Linder, 1945
Family Cyzicidae Stebbing, 1910
Family Eocyzicidae Schwentner, et al., 2020
Family Leptestheriidae Daday, 1913: 44
Family Limnadiidae Burmeister, 1843
Ephippia (singular: ephippium) are winter or dry-season eggs of the various species of small crustacean in the order Cladocera (within the Branchiopoda); they are provided with an extra shell layer, which preserves and protects the resting stages inside from harsh environmental conditions until the more favorable times, such as spring, when the reproductive cycle is able to take place once again. Ephippia are part of the back of a mother carrying them until they are fully developed. After molting, the ephippium stays in the water, or in the soil of dried puddles, small ponds, and vernal pools. The resting stages are often called eggs, but are in fact embryos with arrested development. Ephippia can rest for many years before the embryo resumes development upon an appropriate hatching stimulus. Daphnia Ephippia.jpg
Ephippia (singular: ephippium) are winter or dry-season eggs of the various species of small crustacean in the order Cladocera (within the Branchiopoda); they are provided with an extra shell layer, which preserves and protects the resting stages inside from harsh environmental conditions until the more favorable times, such as spring, when the reproductive cycle is able to take place once again. Ephippia are part of the back of a mother carrying them until they are fully developed. After molting, the ephippium stays in the water, or in the soil of dried puddles, small ponds, and vernal pools. The resting stages are often called eggs, but are in fact embryos with arrested development. Ephippia can rest for many years before the embryo resumes development upon an appropriate hatching stimulus.

Etymology

The word "Cladocera" derives via Neo-Latin from the Ancient Greek κλάδος (kládos, "branch") and κέρας (kéras, "horn"). [19]

The water flea in the photo belongs to the daphnia family. In addition, the photo shows the embryo in her brood pocket Daphnia.sp.jpg
The water flea in the photo belongs to the daphnia family. In addition, the photo shows the embryo in her brood pocket

See also

Related Research Articles

<span class="mw-page-title-main">Branchiopoda</span> Class of crustaceans

Branchiopoda is a class of crustaceans. It comprises fairy shrimp, clam shrimp, Diplostraca, Notostraca, the Devonian Lepidocaris and possibly the Cambrian Rehbachiella. They are mostly small, freshwater animals that feed on plankton and detritus.

<i>Daphnia</i> Genus of crustaceans

Daphnia is a genus of small planktonic crustaceans, 0.2–6.0 mm (0.01–0.24 in) in length. Daphnia are members of the order Anomopoda, and are one of the several small aquatic crustaceans commonly called water fleas because their saltatory swimming style resembles the movements of fleas. Daphnia spp. live in various aquatic environments ranging from acidic swamps to freshwater lakes and ponds.

<span class="mw-page-title-main">Clam shrimp</span> Suborder of arthropods

Clam shrimp are a group of bivalved branchiopod crustaceans that resemble the unrelated bivalved molluscs. They are extant and also known from the fossil record, from at least the Devonian period and perhaps before. They were originally classified in the former order Conchostraca, which later proved to be paraphyletic, because water fleas are nested within clam shrimps. Clam shrimp are now divided into three orders, Cyclestherida, Laevicaudata, and Spinicaudata, in addition to the fossil family Leaiidae.

Alona is a genus of cladocerans in the family Chydoridae. It is one of the largest genera of Cladocera, and is widely believed to be an artificial group which is in need of systematic revision; the type species is Alona quadrangularis. Around 240 names at the species level have been described in Alona; it is unclear how many of these are valid, or how they are related.

Daphnia occidentalis is a species of crustacean in the family Daphniidae. It is endemic to Australia, and is the only species in the subgenus Australodaphnia.

<i>Bythotrephes longimanus</i> Spiny water flea

Bythotrephes longimanus, or the spiny water flea, is a planktonic crustacean less than 15 millimetres (0.6 in) long. It is native to fresh waters of Northern Europe and Asia, but has been accidentally introduced and widely distributed in the Great Lakes area of North America since the 1980s. Bythotrephes is typified by a long abdominal spine with several barbs which protect it from predators.

<i>Bosmina</i> Genus of small freshwater animals

Bosmina is a genus in the order Cladocera, the water fleas. Its members can be distinguished from those of Bosminopsis by the separation of the antennae; in Bosminopsis, the antennae are fused at their bases.

<i>Moina</i> Genus of small freshwater animals

Moina is a genus of crustaceans within the family Moinidae. The genus was first described by W. Baird in 1850. They are referred to as water fleas, but are related to the much larger Daphnia magna and the larger Daphnia pulex. This genus demonstrates the ability to survive in waters containing low oxygen levels, high salinity, and other impurities, including salt pans, and commonly eutrophication. An example of such an extreme habitat is the highly saline Makgadikgadi Pans of Botswana, which supports prolific numbers of Moina belli.

<span class="mw-page-title-main">Daphniidae</span> Family of small freshwater animals

Daphniidae is a family of water fleas in the order Anomopoda.

<i>Daphnia magna</i> Species of small freshwater animal

Daphnia magna is a small planktonic crustacean that belongs to the subclass Phyllopoda.

<i>Leptodora</i> Genus of small freshwater animals

Leptodora is a genus containing two species of large, nearly transparent predatory water fleas. They grow up to 21 mm (0.83 in) long, with two large antennae used for swimming and a single compound eye. The legs are used to catch copepods that it comes into contact with by chance. Leptodora kindtii is found in temperate lakes across the Northern Hemisphere and is probably the only water flea species ever described in a newspaper; L. richardi is only known from eastern Russia. For most of the year, Leptodora reproduces parthenogenetically, with males only appearing late in the season, to produce winter eggs which hatch the following spring. Leptodora is the only genus in its family, the Leptodoridae, and suborder, Haplopoda.

<span class="mw-page-title-main">Anomopoda</span> Suborder of water fleas

Anomopoda is an order of the superorder Diplostraca. These crustaceans, a type of water flea, are members of the class Branchiopoda. The Anomopoda typically have five pairs of thoracic limbs, but sometimes have six pairs. The head of the Anomopoda lacks a clear separation from the trunk and the posterior, while the abdomen area gradually merges with the anterior of the trunk.

<i>Daphnia longispina</i> Species of small freshwater animal

Daphnia longispina is a planktonic crustacean of the family Daphniidae, a cladoceran freshwater water flea. It is native to Eurasia. D. longispina is similar in size and sometimes confused with the often sympatric D. pulex, but much smaller than D. magna. D. longispina is found in a wide range of standing freshwater bodies from small, ephemeral rock-pools to large lakes.

<span class="mw-page-title-main">Sididae</span> Family of small freshwater animals

Sididae is a family of ctenopods in the order Diplostraca. There are about 6 genera and at least 20 described species in Sididae. Some Sididae are non-native species.

<span class="mw-page-title-main">Podonidae</span> Family of small freshwater animals

Podonidae is a family of onychopods in the order Diplostraca. There are about 8 genera and at least 20 described species in Podonidae. A lot of them are non-native species, many of which pose a great threat to aquatic ecosystems.

<i>Daphnia pulicaria</i> Species of small freshwater animal

Daphnia pulicaria is a species of freshwater crustaceans found within the genus of Daphnia, which are often called "water fleas," and they are commonly used as model organisms for scientific research. Like other species of Daphnia, they reproduce via cyclic parthenogenesis. D. pulicaria are filter-feeders with a diet primarily consisting of algae, including Ankistrodesmus falcatus, and they can be found in deep lakes located in temperate climates. Furthermore, D. pulicaria are ecologically important herbivorous zooplankton, which help control algal populations and are a source of food for some fish. D. pulicaria are closely related to Daphnia pulex, and numerous studies have investigated the nature and strength of this relationship because these species can produce Daphnia pulex-pulicaria hybrids. In recent years, D. pulicaria along with other Daphnia species have been negatively affected by invasive predators, such as Bythotrephes longimanus.

<span class="mw-page-title-main">Chydoridae</span> Family of small freshwater animals

Chydoridae is a family of water fleas in the order Anomopoda. There are more than 50 genera and 520 described species in Chydoridae. A lot of Chydoridae species are non-native species, many of which pose a great threat to aquatic ecosystems.

Diaphanosoma is a genus of Sididae.

<span class="mw-page-title-main">Cercopagididae</span> Family of crustaceans

Cercopagididae is a family of crustaceans belonging to the order Diplostraca. A lot of Cercopagididae species are non-native species, many of which pose a great threat to aquatic ecosystems.

References

  1. 1 2 Anderson, Lyall I.; Crighton, William R. B.; Hass, Hagen (December 2003). "A new univalve crustacean from the Early Devonian Rhynie chert hot-spring complex". Transactions of the Royal Society of Edinburgh: Earth Sciences. 94 (4): 355–369. doi:10.1017/S0263593300000742.
  2. 1 2 3 4 5 6 WoRMS (2021). Diplostraca. Accessed at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=155670 on 2021-11-23
  3. ↑ Kotov, Alexey (2007). "Jurassic Cladocera (Crustacea, Branchiopoda) with a description of an extinct Mesozoic order". Journal of Natural History . 41 (1–4): 13–37. Bibcode:2007JNatH..41...13K. doi:10.1080/00222930601164445. S2CID   83483722.
  4. ↑ Kotov, Alexey (2009). "New finding of Mesozoic ephippia of the Anomopoda (Crustacea: Cladocera)". Journal of Natural History . 43 (9–10): 523–528. Bibcode:2009JNatH..43..523K. doi:10.1080/00222930802003020. S2CID   84144888.
  5. ↑ Kotov, Alexey; Korovchinsky, Nikolai (2006). "First record of fossil Mesozoic Ctenopoda (Crustacea, Cladocera)". Zoological Journal of the Linnean Society . 146 (2): 269–274. doi: 10.1111/j.1096-3642.2006.00204.x .
  6. ↑ Kotov, Alexey; Taylor, Derek (2011). "Mesozoic fossils (>145 Mya) suggest the antiquity of the subgenera of Daphnia and their coevolution with chaoborid predators". BMC Evolutionary Biology . 11 (1): 129. Bibcode:2011BMCEE..11..129K. doi: 10.1186/1471-2148-11-129 . PMC   3123605 . PMID   21595889.
  7. ↑ Vernberg, F. John (2014). Environmental Adaptations. Elsevier Science. pp. 338–. ISBN   978-0-323-16282-1.
  8. 1 2 L. Forró; N. M. Korovchinsky; A. A. Kotov; A. Petrusek (2008). "Global diversity of cladocerans (Cladocera; Crustacea) in freshwater" (PDF). Hydrobiologia . 595 (1): 177–184. doi:10.1007/s10750-007-9013-5. S2CID   45363782. doi : 10.1007/978-1-4020-8259-7_19
  9. 1 2 3 4 5 6 7 8 9 10 Douglas Grant Smith; Kirstern Work (2001). "Cladoceran Branchiopoda (water fleas)". In Douglas Grant Smith (ed.). Pennak's Freshwater Invertebrates of the United States: Porifera to Crustacea (4th ed.). John Wiley and Sons. pp. 453–488. ISBN   978-0-471-35837-4.
  10. 1 2 3 4 Denton Belk (2007). "Branchiopoda". In Sol Felty Light; James T. Carlton (eds.). The Light and Smith Manual: Intertidal Invertebrates from Central California to Oregon (4th ed.). University of California Press. pp. 414–417. ISBN   978-0-520-23939-5.
  11. 1 2 Ellen Decaestecker; Luc De Meester; Joachim Mergaey (2009). "Cyclical parthenogeness in Daphnia: sexual versus asexual reproduction". In Isa Schön; Koen Martens; Peter van Dijk (eds.). Lost Sex: The Evolutionary Biology of Parthenogenesis. Springer. pp. 295–316. doi:10.1007/978-90-481-2770-2_15. ISBN   978-90-481-2769-6. S2CID   82949264.
  12. ↑ Thorp and Covich's Freshwater Invertebrates: Keys to Nearctic Fauna
  13. ↑ Van Damme, Kay; Kotov, Alexey A. (December 2016). "The fossil record of the Cladocera (Crustacea: Branchiopoda): Evidence and hypotheses". Earth-Science Reviews. 163: 162–189. Bibcode:2016ESRv..163..162V. doi:10.1016/j.earscirev.2016.10.009.
  14. ↑ Rubbo, Michael J.; Kiesecker, Joseph M. (2004). "Leaf litter composition and community structure: translating regional species changes into local dynamics". Ecology. 85 (9): 2519–2525. Bibcode:2004Ecol...85.2519R. doi: 10.1890/03-0653 .
  15. ↑ Kotov, Alexey A.; Garibian, Petr G.; Bekker, Eugeniya I.; Taylor, Derek J.; Karabanov, Dmitry P. (2020-06-17). "A new species group from the Daphnia curvirostris species complex (Cladocera: Anomopoda) from the eastern Palaearctic: taxonomy, phylogeny and phylogeography". Zoological Journal of the Linnean Society . 191 (3): 772–822. doi:10.1093/zoolinnean/zlaa046. ISSN   0024-4082.
  16. ↑ Norambuena, Juan-Alejandro; Farías, Jorge; De los Ríos, Patricio (2019-12-05). "The water flea Daphnia pulex (Cladocera, Daphniidae), a possible model organism to evaluate aspects of freshwater ecosystems". Crustaceana. 92 (11–12): 1415–1426. doi:10.1163/15685403-00003948. ISSN   0011-216X. S2CID   213266769.
  17. ↑ K. Van Damme; R. J. Shiel; H. J. Dumont (2007). "Notothrix halsei gen. n., sp. n., representative of a new family of freshwater cladocerans (Branchiopoda, Anomopoda) from SW Australia, with a discussion of ancestral traits and a preliminary molecular phylogeny of the order". Zoologica Scripta . 36 (5): 465–487. doi:10.1111/j.1463-6409.2007.00292.x. S2CID   83893469.
  18. ↑ K. Van Damme; R. J. Shiel; H. J. Dumont (2007). "Gondwanotrichidae nom. nov. pro Nototrichidae Van Damme, Shiel & Dumont, 2007". Zoologica Scripta . 36 (5): 623. doi: 10.1111/j.1463-6409.2007.00304.x . S2CID   222187102.
  19. ↑ "Cladoceran". Webster's II New College Dictionary (3rd ed.). Houghton Mifflin Harcourt. 2005. p. 211. ISBN   978-0-618-39601-6.
  20. ↑ USGS Nonindigenous Aquatic Species: Bythotrephes longimanus
  21. ↑ (April 16, 2013) NorthAmericanFishing - "Silent Invaders" Spiny Water Flea PT 1 2013
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