Species descriptions

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
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 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. packardi 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
Habitat	Temporary freshwater pools but is also found in streams and lakes where conditions allow
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
NO PICTURE AVAILABLE
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 and Greenland 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
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
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	Triops australiensis
Subspecies	Triops australiensis australiensis Triops australiensis sakalavus
Range	Australia Madagascar (sakalavus only)
Habitat
Body ring/segments
Appendages
Notable characters	Second maxilla absent
Reproduction

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 France Germany Hungaria Italy Macedonia Portugal Scandinavia Slovakia Spain Sweden Yugoslavia Israel Maltese Islands
Habitat	Temporary fresh or brackish waters
Body ring/segments	32 - 35; 4 - 9 apodous
Appendages	48 - 57
Notable characters	Furca generally long
Reproduction	Bisexual (often female biased), hermaphroditic, and unisexual

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
Body ring/segments
Appendages
Notable characters	Second maxilla present
Reproduction	Bisexual (often male biased)
NO PICTURE AVAILABLE

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)
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

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
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
Subspecies	none
Range	Africa
Habitat	unknown (assumedly identical to T. granarius)
Body ring/segments	--
Appendages	--
Notable characters	--
Reproduction	--
NO PICTURE AVAILABLE
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.

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

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

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

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

Major species	Lepidurus packardi
Subspecies	none
Range	North America Western U.S. (California)
Habitat	Temporary freshwater pools
Body ring/segments
Appendages
Notable characters
Reproduction