Sorry, it should have been hypocoristic, just a convoluted way of saying a pet name. But I should have added that -ma was a patronymic ending, I was just looking it up a minute before hand. They say in the book mentioned below that -ma is hypocoristic and means "man" but that confuses me a little. This is an old list, I should have checked it before I posted that. : (
Hmm, the Tot, Tor, Tom thing, I will have to look up where I found that...wait a minute... I will have to quote for the best explanation: "The preposition 'tot', corresponding to the High German 'zu' is also found fused in the dialect forms 'Ter, Tor, Ten & Tom'. These are shared with Low German surnames from the Rhineland". - under Dutch surnames in Oxford University's 'A Dictionary of Surnames'.