Ybarbo is really Barbo, and has been translated in error by those unfamiliar with Spanish naming customs.
The 'y' is pronounced 'e' in Spanish and is not part of the surname, but a conjunction joing both the maternal and paternal family names.
"In the sixteenth century, the Spanish adopted the copulative conjunction y (“and”) to distinguish a person’s surnames; thus the Andalusian Baroque writer Luis de Góngora y Argote (1561–1627), the Aragonese painter Francisco José de Goya y Lucientes (1746–1828), the Andalusian artist Pablo Diego Ruiz y Picasso (1881–1973), and the Madrilenian liberal philosopher José Ortega y Gasset (1883–1955). In Hispanic America, this spelling convention was common to clergymen (e.g. Salvadoran Bishop Óscar Arnulfo Romero y Galdámez), and sanctioned by the Ley de Registro Civil (Civil Registry Law) of 1870, requiring birth certificates indicating the paternal and maternal surnames conjoined with y — thus, Felipe González y Márquez and José María Aznar y López are the respective true names of the Spanish politicians Felipe González Márquez and José María Aznar López; however, unlike in Catalan, the Spanish usage is infrequent.
The conjunction y avoids denominational confusion when the paternal surname might appear to be a (first) name; hence the physiologist Santiago Ramón y Cajal might appear to be named Santiago Ramón (composite) and surnamed Cajal, like-wise the jurist Francisco Tomás y Valiente, and the cleric Vicente Enrique y Tarancón. Without the conjunction, the footballer Rafael Martín Vázquez, known as Martín Vázquez (his surnames) mistakenly appears to be named Martín rather than Rafael, whilst, to his annoyance, the linguist Fernando Lázaro Carreter occasionally was addressed as Don Lázaro, rather than as Don Fernando.
Moreover, when the maternal surname begins with an i vowel sound, written with either the vowel I (Ibarra), the vowel Y (Ybarra archaic spelling) or the combination Hi + consonant (Higueras), Spanish euphony substitutes the softer-sounded conjunction e in place of the sharper-sounded conjunction y, thus the examples of the Spanish statesman Eduardo Dato e Iradier (1856–1921)."(Source:Wikipedia)
If we go further we find that the name Barbo is rare and can be found in only a few countries:Spain, France, Croatia, and Italy.All of these countries were once part of the Western Roman Empire, and in each country the name has gone through various transformations.
The earliest record of the name was around the year 1000.Pietro Antranigo Barbolano, also called Pietro Barbo, (name change due to nepotism) who during the 11th Century was elected the 28th Doge von Venedig (Duke of Venice)by the assembly of the nobles after the deposition of his predecessor, Otto Orseolo. Barbo was reportedly a descendent of the legendary Eraclea (after whom the town near Venice is named). If proven it would mean that the original version of our family name is not Barbo, but Barbolano.
In conclusion, the name Ybarbo is, in fact, Barbo.The Barbo's may have been the descendants of Venetians, or possibly Greeks if they are decendents of Eraclea.