Only credited animators are Aoki Tetsuro (青木 哲朗) and Satoshi Shigeta (重田 智). If this ( https://www.sakugabooru.com/post/show/35107 ) is also Shigeta's scene, the effects and smears are similar imo.

In “the end credits” of this work, There are only two or one person in the portion of “genga”.
Because there were restrictions on the number of names to be posted on “the end credits” in the old days of Japanese TV animation(Toei etc).

Source: https://twitter.com/kozuma_/status/178000226949402625
>ただ昔は東映などはクレジットの人数に制限ありましたね

The following points can be given as reasons.
First, In “the end credits” at that time, there was a limitation on the portion where names could be displayed, due to the process for ”Satsuei”(taking photographs by film camera).
Second, In the old days, “The end credits” was often handwritten, especially in Toei.

There are exceptions to it, however.
Some animators did "genga" of 1episode(TV animation) by one or two people.

Wow they had choreography in 80's