There seems to be a little confusion on the terms that are used in this Hobby.
Could the members with a Scientific Background give the proper definition to these terms .
Species ?
Sub-Species ?
Cross Breeding ?
Inter-Breeding ?
Proper Terminology for a Shrimp that produces Larva after Hatching ?
Proper Terminology for a Shrimp that produces Larva that require Salt Water to develope ?
Proper Terminology for a Shrimp that produces Larva that require Fresh Water to develope ?
Proper Terminology for a Shrimp that produces Post-Larva after Hatching ?
If this Forum is to remain on the leading edge of providing actuate information to members we need to make sure that the terminology is used correctly and not confusing to the Member asking or the Member answering questions.
John
Terminology Clarification
Moderator: Mustafa
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YuccaPatrol
- Shrimp Master
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- Location: Burning-Ham, Alabama
Newjohn,
I'll do my best to provide this information from my perspective as a biologist.
I'll need just a little bit of time tonight to put it together.
Until then, I will offer an excerpt from a paper I wrote a year ago which had one short section on larval development of shrimp. I can provide the cited references later also.
I'll do my best to provide this information from my perspective as a biologist.
I'll need just a little bit of time tonight to put it together.
Until then, I will offer an excerpt from a paper I wrote a year ago which had one short section on larval development of shrimp. I can provide the cited references later also.
Larval Development of Freshwater Shrimp
Many freshwater shrimp species differ from marine species by their abbreviated or direct larval development. There are three types of larval development described in the literature: the microgenitor type (normal development), the mesogenitor type (abbreviated development), and the macrogenitor type (direct development) (Falciai and Palmerini).
Typical marine shrimp species produce many very small eggs which must undergo a lengthy series of planktonic zoea and other larval stages before metamorphosis into their juvenile/adult forms (Hancock). This is known as the “microgenitor type” of larval development (Falciai and Palmerini). Shrimp with this type of development typically occur in brackish or full strength sea water.
Some species of shrimp have adapted to freshwater habitats by producing fewer, larger eggs which have an abbreviated development in which the eggs hatch at a more advanced larval stage. This is known as the “mesogenitor” type of larval development (Falciai and Palmerini). The planktonic larval stages last only a few days before metamorphosis into a benthic juvenile form. Brackish and freshwater shrimp living in eutrophic lakes or slow moving rivers are more likely to utilize this type of larval development because these habitats tend to be rich in the phyto/zooplankton upon which the larvae feed (Falciai and Palmerini). Many of these species exhibit amphidromous life cycles in which larvae are washed downstream to the coast where they complete development and later migrate upstream to their adult habitat (Benstead et. al.). This reproductive strategy allows these species to utilize the coastal waters to disperse their offspring to other freshwater streams and rivers along the coastline.
Many freshwater shrimp living in fast moving headwater streams produce few, very large eggs which undergo direct development. Fully (or nearly fully) developed juvenile forms hatch directly from the eggs without any planktonic larval stages (Yam and Dudgeon). This is described as the “macrogenitor type” of larval development (Falciai and Palmerini). Because these newly hatched larvae are capable of immediately assuming a benthic lifestyle, they are less vulnerable to being washed out of their preferred habitat by rapidly flowing water. This is of particular importance because many of these species live at temperate latitudes where breeding is triggered by a rise in temperature occurring simultaneously with the summer monsoon season. (Yam and Dudgeon).
Of the three types of larval development, the completely suppressed macrogenitor type is most common among freshwater shrimp currently being bred in captivity for the aquarium trade. Because these shrimp do not undergo a complex series of larval stages before metamorphosis, do not require living planktonic food sources, and can survive without being transitioned to brackish or salt water, their full lifecycles can easily be completed in freshwater aquaria.
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YuccaPatrol
- Shrimp Master
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- Location: Burning-Ham, Alabama
Species and sub-species: It should be simple, but the definition of a species is one of the most difficult things to describe and it is something that biologists and taxonomists continue to argue over and they probably always will. This argument has even been given a name: "the species problem".
A very basic definition that most would agree on is that a species is a group of similar organisms which can breed and produce fertile offspring.
However, how biologists interpret this simple definition can vary wildly.
Some biologists look at very minute differences between organisms and want to give each one a unique species name. Some others prefer to describe these small differences as subspecies. Others want to lump them all into one larger species complex without naming individual subspecies.
So now we need a basic definition of a subspecies. This can be defined as a distinct population which is somehow isolated (usually geographically) from other populations of the same species and has some measurable characteristics which differentiate it from other populations (size, coloration, behavior, etc) but could still breed successfully with members of other subspecies.
A very basic definition that most would agree on is that a species is a group of similar organisms which can breed and produce fertile offspring.
However, how biologists interpret this simple definition can vary wildly.
Some biologists look at very minute differences between organisms and want to give each one a unique species name. Some others prefer to describe these small differences as subspecies. Others want to lump them all into one larger species complex without naming individual subspecies.
So now we need a basic definition of a subspecies. This can be defined as a distinct population which is somehow isolated (usually geographically) from other populations of the same species and has some measurable characteristics which differentiate it from other populations (size, coloration, behavior, etc) but could still breed successfully with members of other subspecies.
Last edited by YuccaPatrol on Wed Apr 18, 2007 4:03 am, edited 1 time in total.
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ToddnBecka
- Shrimpoholic
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- Location: Western Maryland
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ToddnBecka
- Shrimpoholic
- Posts: 363
- Joined: Wed May 24, 2006 11:12 pm
- Location: Western Maryland
)
That is not a species by the way. The "cf" just means it is like C. babaulti but it for sure isn't. Many different species, even ones that could not interbreed with each other, can be called "Caridina cf. babaulti" if nobody knows what they really are and C. babaulti has the most similar morphology. Once such a species has either been identified or newly described it will have a totally different name that bears no similarity to C. babaulti (e.g. "Caridina joeblowi"milalic wrote: I believe Caridina cf. babaulti is one of them as well
). If you are trying to say that the green shrimp has free-floating larvae, then, that is not true. The green shrimp produce benthic offspring. They might go through a few "postlarval" stages, but they are, for all hobby purposes, miniature versions of the adult. I do, however, have several shrimp species, including the sri lanka dwarf shrimp, that have freshwater larvae. The shrimp varieties pages have a few of them and I have a few that are not on the shrimp varieties pages, yet.
John,
The larval development type descriptions (normal, abbreviated, direct) in the shrimp varieties pages are all terminology commonly used in scientific papers. I might chime in on some of the rest of your questions some other time (organizing the move is taking up most of time right now), but I think YuccaPatrol has done an excellent job explaining already.
Any established population of new species of shrimp is an asset to the hobby. 
