Giuseppe Donati is widely considered the inventor of the transverse ocarina (10 hole system)

The double ocarina has multiple contenders for who may have invented the instrument- Luigi Silvestri, Emilio Cesari, and Antonio Canella ^{1) 2)}
Antonio Canella invented an instrument he called the bi-ocarina
Other makers by the name of Guido Chiesa and Menaglio who seem to be students on someone named Vicinelli
someone named Mignani who bought tools from Emilio Cesari

Guido Bondi ³⁾

The first triple ocarina is widely considered to be made by Emilio Cesari who was a student of Donati.

Primarily Researched by-

Jack Campin ⁴⁾
Giorgio Pacchioni
Claudio Cedroni
Wollemi Pine (real name unsure right now) ⁵⁾

Wollemi Pine and Jack Campin are the only ones really researching this topic in English.

A better organized tree of some sort is needed to sort out the original Italian makers, what were there exact relationships.
Claudio Cedroni's ocarina history book appears to be taken seriously but the book is very hard to find. ⁶⁾

Primarily Researched by-

Samuel Marti
Roberto Velázquez Cabrera ⁷⁾
Susan Rawcliffe

Outline the distinctions between cultural works, everyone seems to talk about this topic as just mesoamerican or even all new world ocarinas combined together, The Olmec, Maya, and Aztec examples are all from different time periods, all have dramatically different reference points in physical geography and culture, and should not be considered to be too similar as there is unlikely direct cultural influence.
article on various cultural instruments ⁸⁾
Instruments of northern Honduras ⁹⁾
Musical instruments of Maya regions ¹⁰⁾
Ecuador ¹¹⁾

Images of original ocarinas ^{12) 13) 14)}
Brief introduction to precolombian ocarinas with Dr. Jose Cuellar and Dr. David Carrasco. ¹⁵⁾