Kk. Holden et Mn. Bruton, THE OCCURRENCE AND DEVELOPMENT OF SIAMESE TWINS AND OTHER ABNORMALITIES IN OREOCHROMIS-MOSSAMBICUS (PISCES, CICHLIDAE), South African journal of zoology, 28(2), 1993, pp. 107-112
Specimens from a clutch of Oreochromis mossambicus (Pisces, Cichlidae)
exhibited a number of abnormalities such as enlarged pericardia, thin
tube-like hearts, large depressions in the yolksac, spinal deformitie
s and twinning. Descriptions of the differences in early ontogeny of t
wo pairs of 'Siamese twins' over a period of at least eight days are g
iven. The developmental pattern of the twins is similar to that of nor
mal specimens but the developmental rate is slower in the twins. Possi
ble explanations for these occurrences of polyembryony are given.