yes, OED2 has ortho-cousin listed under ortho- n. Anthropol. = parallel cousin s.v. PARALLEL 4a. >> 4. a. parallel cousin = ortho-cousin (ORTHO 1).
1936 R. FIRTH We, the Tikopia vi. 221 The differentiation between cross-cousin and parallel cousin is certainly not one of the outstanding features of the Tikopia kinship system. 1949 F. EGGAN in M. Fortes Social Struct. 124 Parallel cousins are treated as siblings, whereas cross~cousins are differentiated. 1970 E. LEACH Lévi-Strauss 121 A parallel cousin..is a cousin of the type ‘mother's sister's child’ or ‘father's brother's child’. 1972 [see ortho-cousin s.v. ORTHO- 1].
>>cross-cousin, one of two cousins who are the children of a brother and a sister respectively; also attrib. in cross-cousin marriage
going back to ortho-, this gives some insight into how there came to be two terms for this one:
1918 J. G. FRAZER Folk-lore in Old Test. II. II. vi. 98 It has become customary to call the marriageable cousins cross-cousins, because..the related parents are of opposite or cross sexes. There has hitherto been no special name for the unmarriageable cousins, the children of two brothers or of two sisters, but for convenience I propose to call them *ortho-cousins to distinguish them from cross-cousins. In the case of ortho-cousins the related parents are of the same sex. 1932 Brit. Jrnl. Psychol. Jan. 265 All ortho-cousins are forbidden, while cross-cousins are considered suitable mates. 1972 D. DAVIES Dict. Anthropol. 141 Ortho-Cousin, a term little used now,..can be a synonym for parallel cousin..or for a parallel cousin of the same unilineal descent..group as the person concerned.
as we've often seen here, neologisms don't automatically generate universal favor.
