Dan Quayle, selected for the No. 2 spot on the Republican presidential ticket, could well be one of the wealthiest members of Congress. But the Indiana senator lists as his only substantial asset newspaper stock valued at "$250,000 and above."

If Quayle's stock in the family controlled Central Newspapers Inc., headquartered in Indianapolis, were worth $250,000 or so, he would not be among the estimated one-third of senators who are millionaires.But federal law requires financial disclosure by members of Congress and other officials of only broad categories. The highest category for assets is "$250,000 and above" - whether the asset is worth $250,001 or more than $500 million.

In addition, the laws do not require that the actual value of an asset be listed; thus, Quayle's statement uses book value for the newspaper stock, which probably understates its value dramatically.

The 41-year-old Quayle is reputed to be in line to inherit several million dollars worth of stock in the newspaper group, whose holdings include the Indianapolis Star and Indianapolis News in Indiana and the Arizona Republic and Phoenix Gazette. His uncle, Eugene Pulliam, is publisher of the newspapers.

The senator's financial disclosure statement also lists his wife as owning a block of Central stock, with a book value of $100,001 to $250,000.

Except for the stock in Central Newspapers, Quayle's only holdings last year were two retirement accounts totaling a maximum of $65,000; a bank account worth up to $15,000, and an account in the House of Representatives credit union of $1,000 to $5,000.