VERY communal species to be kept at 80-85 Fahrenheit and 60% humidity. They are burrowing scorpions and like plants...a lot! At least, according to $$$$. Maximum adult size is accordingly around 3 inches. Like Dave said, it is a short lived Buthid. Again, as Dave said, Kugellager can probably go farther in depth than myself on them. I have been looking into them more, but currently do not keep them. Will be keeping them soon though.
M.martensii are a cool little communal species that are very active in the early evening...when I used to have my scorps in my bedroom I would hear them running around their tank for 2+ hours after lights out.
I never had mine make anymore than a half hearted attempt to make a scrape. I provided two scrapes for the four individuals I kept. One was purposely warmer than the other to give them a choice. The temps and humiditys are as described above. I misted them once or twice a month and added water to waterdish once a week with occasional overflows.
They are pretty adaptable to living conditions as in the book "Catalogue of the Scorpions of the World" they list China, Korea, Mongolia, and Singapore as countries where they are found and Polis reports that they have even been found under wet rocks on the coast line.
Their venom is reportedly moderately dangerous and their is a sting report on Darrin Vernier's site here:
If you look on the LD50 link in the sticky at the top of this forum you will note that the potency is quite high. One must remember that this is a small scorp and therefore injects small amounts of venom. I have heard a sting from M.martensii is comparable to that of C.exilicauda...not deadly(in nearly all cases)...but quite painful as you read in the sting report.
When I kept them I ordered a batch of four adults. Two of them turned out to be gravid females and subsequently had a litter of scorps each. The total # between the two was about 30 but I missed catching the first litter and most were munched by the other adults. The second litter I noticed right away and removed the mother with the young on her back immediately. Her litter was 21 babies. They were very easy to raise communally...though I gave all of them away before they matured.
They do have short life spans as stated above. The two females I had die w/in two months of giving birth and the other two died by last December. I had them about a year max, but they were already adults. Should have kept a bunch of the juvies then I could have had a self sustaining colony.
They are a communal species that I will surely keep again as care is quite easy and the seem to be easy to raise the young with some care and common sense. They also did not seem particularly aggressive when maintaining their enclosure...never tagged my prod sticks once. They are also visible quite often.