NEW YORK — He stood a majestic 5-foot-5, weighed around 100 pounds and maybe had a harem. That’s what scientists figure from the footprints he left behind some 3.7 million years ago.

He’s evidently the tallest known member of the prehuman species best known for the fossil skeleton nicknamed “Lucy,” reaching a stature no other member of our family tree matched for another 1.5 million years, the researchers say.

The 13 footprints are impressions left in volcanic ash that later hardened into rock, excavated last year in northern Tanzania in Africa. Their comparatively large size, averaging a bit over 10 inches long, suggest they were made by a male member of the species known as Australopithecus afarensis.

The prints were found at a site called Laetoli, which is famous for another set of smaller footprints left by other A. afarensis individuals. Those made headlines in the 1970s as the earliest clear evidence of upright walking by our ancestors. The newly discovered prints are only about 160 yards away.

Researchers named the new creature S1, for the first discovery made at the “S” site. From the footprints, they calculated that he stood about 5-foot-5 and weighed around 100 pounds.

They figured that he loomed at least 8 inches above the individuals who made the other tracks, and stood maybe 3 inches taller than a large A. afarensis specimen previously found in Ethiopia. “Lucy,” also from Ethiopia, was much shorter at about 3½ feet.

But not everybody agrees with their analysis.

Their estimate is suspect, said anthropologist William Jungers, a research associate at the Association Vahatra in Madagascar who wrote a commentary on the study. That’s because scientists haven’t recovered enough of an A. afarensis foot to reliably calculate height from footprints, he said in an e-mail.