The "original" author of these anime are group instead of one person.

When Kunihiko Ikuhara created Revolutionary Girl Utena, he creates the group named Be-Papas and discuss the main story in the group. The other group members are Chiho Saito who is manga writer and Youji Enokido who is story writer. Ikuhara created anime version of Utena, and in same time Saito writes manga version of Utena. They discuss main story of Utena, but they created independently and the detail of story was different.

Both anime and manga was original, both are not an adaptation.

Ikuhara did same thing for Mawaru Penguindrum and Yuri Kuma Arashi. The member is different, but they created main story by group and create manga and anime version separately.

By creating by group, they can create more good story. On the other hand, They can release anime, manga and novel version at same time, it will get more good sales by synergy effect.

Ikuhara is not only person who use group system. An old robot anime Patlabor was created by the group Head Gear. For newer example, Madoka Magica was created by the group Magica Quartet.

The "original" author of these anime is a group rather than a single person.

When Kunihiko Ikuhara created Revolutionary Girl Utena, he created the group named Be-Papas and discussed the main story with the group. The other group members are Chiho Saito who is a manga writer and Youji Enokido who is a story writer. Ikuhara created the anime version of Utena, and at the same time Saito wrote the manga version of Utena. They discussed the main story of Utena, but they created the different works independently and the details of each story were different.

Both anime and manga were original works; neither is an adaptation of something.

Ikuhara did same thing for Mawaru Penguindrum and Yuri Kuma Arashi. The group members are different, but they created main story as a group and created the manga and anime versions separately.

By creating as a group, they can create a better story. They can also release anime, manga and novel versions at same time; this will lead to better sales by a synergy effect.

Ikuhara is not only person who use group system. An old robot anime Patlabor was created by the group Head Gear. For newer example, Madoka Magica was created by the group Magica Quartet.