The sentence is saying, most likely the name is Italian, but there is also a smaller chance that it is either Spanish or Russian. That is, is possible also that the name is Spanish or Russian, but this likelihood is smaller than the likelihood of it being Italian.

Less likely means that the possibility of something is less than the possibility of another thing. Here it means that the name is most probably Italian, but it can also appear to be Spanish or Russian. The possibility of the name to be Italian is more than the possibility of it to be Spanish or Russian. :) Hope it was helpful and I did not confuse you :))) I also want to give the links that will be interesting and helpful to you and other guys who learn Russian. http://www.learning-to-know.com/#!marathon/cx9x. http://www.learningtoknowrussian.com/ https://www.facebook.com/LearningToKnow

'not as likely'