Question: Tommaso "Tommy" Gagliano was an American mobster and boss whose successor was a longtime loyalist, underboss and founding member of what in the United States?
Context: Steven Lorenzo Crea (born July 18, 1947), is an American mobster.  He is a member of the Mafia (Cosa Nostra) and the current underboss of the Lucchese crime family. Michael "The Nose" Mancuso (born 1955), is an American mobster.  He is a member of the American Mafia (Cosa Nostra) and the boss of the Bonanno crime family, one of Five Families in New York City. Steven Mazzone (born 1964) is an American mobster believed to be a high ranking member of the Philadelphia crime family.  Mazzone's rise in power through the Philadelphia underworld began as a protege of former boss turned informant, Ralph Natale.  After the family was decimated by prosecutions during the Nicodemo Scarfo and John Stanfa eras, Natale was released from prison in 1994 and shortly thereafter became the new boss of the crime family.  Natale partnered with the "Young Turks" faction that was one of the few remnants left of the Philadelphia crime family, and their leader, Joseph "Skinny Joey" Merlino.  After Natale assumed the top position as boss, he positioned Merlino as underboss and Ronald Turchi as the consigliere in the new hierarchy.  This administration is still in question to this day, as many now believe that Merlino was running the family behind the scenes, letting Natale have the boss position to deter law enforcement from himself. Joseph Salvatore "Skinny Joey" Merlino (born March 16, 1962) is an American mobster believed to be the boss of the Philadelphia crime family despite the appearance of having various legitimate business fronts as well as accounts from acting bosses; led it primarily in loan sharking, gambling and extortion.  During the 1990s, Merlino began a mob war within the crime family and survived numerous assassination attempts.  By 1995 he was the effective leader of the Philadelphia crime family.  Unlike most mobsters who shunned the limelight, Merlino always enjoyed the publicity from the media and the public.  He is the son of deceased Scarfo crime family Underboss Chuckie Merlino. Tommaso "Tommy" Gagliano (May 29, 1883 − February 16, 1951) was an American mobster and boss of the Lucchese crime family, one of the "Five Families" of New York City.  He served as a low-profile boss for over two decades.  His successor was his longtime loyalist and underboss, Gaetano "Tommy" Lucchese. Girolomo "Momo" Adamo (1895–1956) was an Italian American mobster in the American Mafia.  He lived in Chicago and Kansas City before moving to Los Angeles in the 1930s and soon became underboss to Jack Dragna in the Los Angeles crime family.  His brother Joseph Adamo was also a member of the crime family.  Both he and his brother were well connected criminals in San Diego, working with such mobsters as Frank Bompensiero.  In 1950, Momo was arrested along with several members of Jack Dragna's family including Tom Dragna (brother), Louis Dragna (nephew), and two men named Frank Paul Dragna (his son and nephew, respectively) after Jack fled the state after being named in the California Crime Commission report as a member of a crime syndicate in Los Angeles.  The five of them were taken into custody by the Los Angeles Police Department, who believed they were responsible for bombing Mickey Cohen's home or knew who was.  They were all released without being charged when the police couldn't find evidence of their involvement (Tom built the bomb, but otherwise none of them were involved). Thomas "Tommy" Lucchese (pronounced ] ; born Gaetano Lucchese, December 1, 1899 – July 13, 1967) was a Sicilian-born American gangster and founding member of the Mafia in the United States, an offshoot of the "Cosa Nostra" in Sicily.  From 1951 until 1967, he was the boss of the Lucchese crime family, one of the Five Families that dominates organized crime in New York City. Joseph "Joe" Miranda (born 1925) is an American mobster and member of the New Jersey-based DeCavalcante crime family.  A longtime "soldier" to Simone "Sam the Plumber" DeCavalcante and later boss Giovanni Riggi, he became acting underboss for Girolamo "Jimmy" Palermo following the imprisonment of many high-ranking members in 2003. Simone "Sam" Scozzari was a Sicilian mobster and a member of the American Mafia in Los Angeles.  He served as a soldier in the Los Angeles crime family during the 1940s and 1950s.  When Frank DeSimone became boss of the L.A. crime family in 1956, he promoted Scozzari underboss. Antonino Joseph "Tony" Accardo (born Antonino Leonardo Accardo; April 28, 1906 – May 22, 1992), also known as "Joe Batters" or "Big Tuna", was a longtime American mobster.  In a criminal career that spanned eight decades, he rose from small-time hoodlum to the position of day-to-day boss of the Chicago Outfit in 1947, to ultimately becoming the final Outfit authority in 1972.  Accardo moved the Outfit into new operations and territories, greatly increasing its power and wealth during his tenure as boss.
Answer: the Mafia