Watching the World Cup, Argentina has no dark skinned players whilst countries such as Brazil and Costa Rica seem to have a large contingent of players who appear to be of African descent, Is there a historic reason for this. Also, is there a reason there are so many Italian sounding names in the Argentine squad?
Argentina once had a much higher proportion of black people relative to its population: something like a fifth of its total population in the early 19th century (similar to the US at that time, incidentally). Slavery was ended in 1853 (compared to 1888 in Brazil), and after that time there was an intentional effort by the various regimes in Buenos Aires to encourage specifically white European immigration, especially from Spain and Italy. This policy lasted through the mid 20th century and had a huge impact on Argentinian demographics.
Also keep in mind that during this period Argentina had a relatively low population (something like 700,000 in the 1820s and less than 5 million by 1900). The population began to grow from immigration and domestic demographic changes mostly in the 20th century.
This is mostly from Edwin Williamsons Penguin History of Latin Amercia and me checking my copy of The Times' Concise Atlas of World History. My limited academic study of Latin American history didn't touch too much on 19th Century Argentina, so I preemptively defer to a Latin American expert.
ETA - of course I'm just talking about historic demography, and that's different from the history of which racial groups get access to professional sports and national football teams in Latin America, which is a different and very interesting topic that I am completely unqualified to discuss (but eager to learn about!).