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Species Descriptions by Chip Hannum (upd: Stuart Halliday).

Below are tables describing briefly what I know about the 15 major species.   Do not take my range descriptions as gospel; no mention does not mean a species is not present somewhere and a mention is hardly a guarantee.  Available information is sometimes sketchy and I've noted more questionable points with a question mark. 

Major species Lepidurus apus
Subspecies Lepidurus apus apus
Lepidurus apus lubbocki
Lepidurus apus patagonicus
Lepidurus apus viridis
Range Africa (North)
Asia
Australia (viridis only)
Europe
  • Austria
  • Bosnia
  • Croatia
  • Czech Republic
  • Denmark
  • France
  • Germany
  • Herzegovina
  • Hungaria
  • Italy
  • Macedonia
  • Morocco
  • Scandinavia
  • Slovakia
  • Spain
  • Yugoslavia

Israel
New Zealand
South America (?)

Habitat Temporary but often longer lasting freshwater pools
Temperature range Unknown
Body ring/segments 26 - 29; 4 - 6 apodous
Appendages 35 - 48
Notable characters Round or oval dorsal organ, second maxillae present, no supernumerary spines on apodous segments
Reproduction Bisexual, Hermaphroditic

l_apus.jpg (19029 bytes)

L. apus has one of the greatest ranges of any of the triops being found throughout continental Europe, Northern Africa, and one of only two notostracans found in Australia.  Life cycle is typical of the lepidurans with a significant percentage of laid eggs hatching after a few weeks in the water.

One of the more controversal of the species as Longhurst originally lumped L. couesii and L. packardii into the species in spite of distinct characters that argued otherwise.

Longhurst mentions a South American subspecies L. apus patagonicus but I have found no reference to this triops anywhere outside of his paper.

 

Major species Lepidurus arcticus
Subspecies none
Range Asia (Northern)
  • Kuril Archipelago
  • Russia

Europe (Northern)

  • Norway
  • Greenland
  • Svalbard
Habitat Cold temporary freshwater pools but is also found in streams and lakes where conditions allow
Temperature range Minimum 4-7°C
Body ring/segments 26 - 28; 4 - 5 apodous
Appendages 41 - 46
Notable characters The endites of the 1st thoracic appendage barely reach edge of the carapace, supra anal plate very small relative to other Lepidurus, second maxilla present
Reproduction Bisexual (female biased) and hermaphroditic

L. arcticus is one of the most unique of the triops.  Not only does it inhabit permanent fresh bodies of water, it is even known to coexist with arctic charr in some deep Norwegian, Greenland and Svalbard lakes.  As a rule, though, it lives in high arctic lakes shallower than 6 meters - the lakes freeze completely during the colder seasons and this keeps fish from living there.  Scientists are actively studying the trophic relation between L. arcticus and the arctic charr in those lakes they coexist in to understand the delicate ecology better.

 

Major species Lepidurus batesoni
Subspecies none
Range Russia
Habitat unknown
Temperature range Unknown
Body ring/segments 33, 8 apodous
Appendages 49 - 52
Notable characters Carapace more rounded than typical in Lepidurus, endite 6 of the first thoracic appendage is developed into a claw like structure (it is reduced to a small lobe in all other notostracans), second maxilla present
Reproduction Bisexual (see comments below)

NO PICTURE AVAILABLE

There is very little known about this species, I'm not even sure if it's currently believed to exist.  It is known only from a handful of males collected and preserved in the early 1900s.  The claw like endite of the 1st thoracic appendage argues strongly that it is/was a distinct species.

 

Major species Lepidurus bilobatus
Subspecies none
Range North America (midwest to southwest)
Habitat unknown exactly but believed to be temporary freshwater pools
Temperature range Hatching Temp: 10-15°C (50-59°F)
Body ring/segments 33; 6 apodous
Appendages 60
Notable characters  
Reproduction unknown

NO PICTURE AVAILABLE

A species of questionable authenticity, known only from its first description in the late 1800s and two specimens ascribed to it by a naturalist (Linder) in 1952.  There are no preserved specimens and next to nothing is known about its biology.

 

Major species Lepidurus couesii
Subspecies none
Range North America
  • Canada
Habitat Temporary alkaline freshwater pools
Temperature range Unknown
Body ring/segments  
Appendages  
Notable characters  
Reproduction  

 

 

 

Major species Lepidurus cryptus
Subspecies none
Range West of North America (California),
Habitat Temporary lakes, pools
Temperature range Unknown - assume same as l. lemmoni
Body ring/segments 24 to 29 body rings
Appendages 30 to 35 pairs of legs
Notable characters Length - 15-60 mm
Reproduction Female

 

 

 

Major species Lepidurus lemmoni
Subspecies none
Range North America
  • Mexico
Habitat  
Temperature range Unknown
Body ring/segments  
Appendages  
Notable characters  
Reproduction  

 

 

 

Major species Lepidurus lynchi
Subspecies none
Range  
Habitat  
Temperature range Unknown
Body ring/segments  
Appendages  
Notable characters  
Reproduction  

 

 

 

Major species Lepidurus mongolicus
Subspecies none
Range  
Habitat  
Temperature range Unknown
Body ring/segments  
Appendages  
Notable characters  
Reproduction  

 

 

 

Major species Lepidurus packardii
Subspecies none
Range North America
  • Western U.S. (California)
Habitat Longer lasting and permanent freshwater pools
Temperature range Minimum Temp: 18°C (64°F) Maximum Temp: 30°C (86°F)
Body ring/segments  
Appendages  
Notable characters Eggs require little drying out time, can on occasion reach lengths of 86mm
Reproduction  
Life span Approximately 140 days

lpackardi_2.jpg (4920
    bytes)

 

 

Major species Triops australiensis
Subspecies Triops australiensis australiensis
Triops australiensis sakalavus
Range Australia
Madagascar (sakalavus only)
Habitat  
Temperature range Minimum Temp: 18°C (64°F) Maximum Temp: 30°C (86°F)
Body ring/segments  
Appendages  
Notable characters Second maxilla absent
Reproduction  

taustraliensis_2.jpg

One of two notostracans found in Australia, it is known as a shield shrimp.

T. australiensis sakalavus is known to me by name only.

 

Major species Triops cancriformis
Subspecies Triops cancriformis cancriformis
Triops cancriformis mauretanicus
Triops cancriformis simplex
Range Africa
  • Senegal
  • South Africa

Asia

  • India (?)
  • Japan
  • Russia

Europe

  • Austria
  • Czech Republic
  • Denmark
  • England
  • France
  • Germany
  • Hungaria
  • Italy
  • Macedonia
  • Portugal
  • Scandinavia
  • Scotland
  • Slovakia
  • Spain
  • Sweden
  • Yugoslavia

Israel
Maltese Islands

Habitat Temporary fresh or brackish waters
Temperature range Minimum Temp: 10°C (50°F) Maximum Temp: 28°C (82°F)
Body ring/segments 32 - 35; 4 - 9 apodous
Appendages 48 - 57
Notable characters Furca generally long
Reproduction Bisexual (often female biased), hermaphroditic, and unisexual
Life span Approximately 100 days. Usually half that in a Aquarium.

tcancriformis_6.jpg (10352 bytes)

Along with T. longicaudatus, and L. apus, this is the most widespread and common of the triops.  Next to T. longicaudatus, it is the most studied.  It also shares the honor of being considered a rice crop pest with T. longicaudatus.

Notable in that it is probably the "proto-triops" from which all the others have evolved in the past 200 or so million years, it is also the oldest known living species of any animal.

 

Major species Triops granarius
Subspecies none
Range Africa
  • South Africa

Asia

  • China
  • Japan

Europe

  • Italy
Habitat  
Temperature range Unknown
Body ring/segments  
Appendages  
Notable characters Second maxilla present
Reproduction Bisexual (often male biased)
 

 

Major species Triops longicaudatus
Subspecies none official*
Range North America
  • United States (also in Hawaii but not Alaska)
  • Mexico

Central America
South America
Japan
West Indies
Galapogos Islands
New Caledonia

Habitat Temporary waters (a common inhabitant of rice fields in the U.S. and Japan)
Temperature range Minimum Temp: 18°C (60°F) Maximum Temp: 30°C (86°F)
Body ring/segments 35 - 44, 5 - 12 apodous in females, 10 - 14 apodous in males
Appendages 54 - 66
Notable characters Second maxilla is absent
Reproduction Bisexual (with both male and female biased populations known), unisexual, and hermaphroditic
Life span Approximately 80-90 days. Usually half this in an Aquarium.

tlong_pool.jpg (25950
    bytes)

T. longicaudatus is your " garden variety" triops.  This is the species that gets sold throughout the world in triops kits.  It is the most studied of all the Triops and Lepidurus species and, hence, the one we know the most about.

* As mentioned elsewhere, because it is studied more than any other species genetic data suggest that there are probably several if not dozens of subspecies currently lumped together as a single macrospecies.   At the level of gross anatomy, there are two distinct morphs: a long form and a short form which can be distinguished by the number of segments/tail length not coverd by the carapace.

 

Major species Triops newberryi
Subspecies none
Range North America
  • United States
Habitat Temporary waters
Temperature range Minimum Temp: 18°C (60°F) Maximum Temp: 30°C (86°F)
Body ring/segments --
Appendages --
Notable characters --
Reproduction --

NO PICTURE AVAILABLE

This species is found in the North American south and southwest with considerable overlap with T. longicaudatus

Unfortunately, that's about all I know.  The species was not described by Longhurst but is mentioned a few times in modern papers.  However, no details other than geographic distribution and habitat are given.  Presumably, it was defined as a species in a paper I have not managed to get ahold of nor find a citation for.

 

Major species Triops numidicus (strongly thought to be T. granarius
Subspecies none
Range Africa
Habitat Unknown (assumedly identical to T. granarius)
Temperature range High 20-30C
Body ring/segments --
Appendages --
Notable characters Large size in wild specimens (typically 4-5 inches long)
Reproduction --

Triops numidicus on a hand

T. numidicus is interesting in that I am uncertain whether or not it is regarded as a valid species.  Longhurst regarded it as synonym for T. granarius.  In recent papers I have seen it referred to both as a valid species and as an outdated name for T. granarius.   Unfortunately, references to it are all that exist to my knowledge and I have yet to find a paper defining it as a species or its characteristics.