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Sieburg Rex
A Rex mutation which occurred in 1979 in Sieberg, Germany. It was not the same mutation as the existing German Rex and the cat was neutered, causing the mutation to be lost.
Singapura Longhair
The only known example of this mutation was neutered. It was identical to the Singapura in all respects apart from the semi-long coat.
Singhalese
Bred in 1967, colourpoint versions of Siamese resulting from Siamese x Angora (red/red tabby) crossings. Fur was shorter, but fluffier than the Balinese, tail was very fluffy, temperament closer to the Angora (less highly strung). These were the red-series equivalents of Balinese which US fancies recognised only in seal, blue, lilac anc chocolate. The Singhalese was allowed to be bred to either Balinese or Himalayan and the progeny still be Singhalese. It was judged to the Balinese standard with allowances made for the different coat type.
Snow-Toes
Birman x Himalayan cross bred in the late 1960s (USA). Not related to the Snowshoe.
Suqutranese
White Somali-type semi longhair; white fur with glistening silver banding. Suqutranese standard is otherwise nearly identical to Somali standard. They were exhibited in March 1990 (UK). In August 1995, Somali Cat Breed Advisory Committee objected to advertisements for "so-called White Somalis" (this term was descriptive, not a breed name). Since then, nothing has been heard of the Suqutranese though a number of Somali breeders overseas have since shown interest and it would be possible to recreate the type. Also known as Socotranese.
Note: In a near parallel of this, during the mid/late 1990s a Somali breeder experimentally crossed Somalis with black shorthairs to create a cat of Somali type but with black fur with a distinct "shimmer".
Sumxu
Now considered extinct, once found in the area around Peking, China. Longhair cat, glossy black or yellow coat and pendulous ears. Described in early 1700s as a curiosity, also in 1796 (droop-eared cat brought back from China) and in 1938 (another droop-eared cat imported). In 1938, the mutation was thought to be restricted to white longhaired cats.