Two new species of the genus Botryllophilus Hesse, 1864 are described on the basis of females living in compound ascidians collected in Madagascar. These copepods (Botryllophilinae) are readily distinguished from each other by body form. The copepods and ascidian hosts are as follows: 1) Botryllophilus spinulosus (metasome not inflated dorsally, with urosome shorter than prosome), in an undescribed, new species of Synoicum; 2) B. distinctus (metasome inflated dorsally, with urosome about equal to prosome), in Eudistoma sp. The two new copepods belong to subgroup 2 of female morphotype A (urosome 5-segmented) of the genus. Six Botryllophilus species (four known, two new) of subgroup 2 are compared to each other relative to their leg armature formulas of pattern II. The two new copepods belong to the Humes collection from Madagascar (1963, 1964).
Botryllophilus (female morphotype A; subgroup 2)