Remarks.
Psammonyx Bousfield, 1973 currently contains eleven species (Horton et al. 2018). The genus was established by Bousfield in 1973, for the single species Psammonyx nobilis (Stimpson, 1853), designated as the type of the genus (as Anonyx nobilis Stimpson, 1853). A second species (P. terranovae Steele, 1979) was added by Steele in 1979, and in 1982, Jarrett and Bousfield described a third species (Psammonyx longimerus Jarrett & Bousfield, 1982) and transferred the fourth species Psammonyx kurilicus (Gurjanova, 1962) from the genus Hippomedon.
In 2005, Budnikova added two further species (Psammonyx kudrjaschovi Budnikova, 2005 and Psammonyx tzvetkovae Budnikova, 2005) and placed the genus Wecomedon Jarrett & Bousfield, 1982 in synonymy with Psammonyx, transferring the five species it contained to Psammonyx (P. boreopacificus (Gurjanova, 1962); P. minusculus (Gurjanova, 1938) P. similis (Jarrett & Bousfield, 1982); P. wecomus (J.L. Barnard, 1971); and P. wirketis (Gurjanova, 1962)).
According to ICZN article 60.2 the oldest available and potentially valid synonym of the rejected junior homonym becomes the valid name of the taxon (see ICZN Article 23.3.5), and takes its own authorship and date. Therefore, the replacement name for Psammonyx Bousfield, 1973 is Wecomedon Jarrett & Bousfield, 1982, with Hippomedon wecomus J.L. Barnard, 1971 as the type species of the genus.
Wecomedon is now comprised of the following eleven species:
Wecomedon boreopacificus (Gurjanova, 1962), comb. n. Original name Hippomedon boreopacificus;
Wecomedon kudrjaschovi (Budnikova, 2005), comb. n. Original name Psammonyx kudrjaschovi;
Wecomedon kurilicus (Gurjanova, 1962), comb. n. Original name Hippomedon kurilicus;
Wecomedon longimerus (Jarrett & Bousfield, 1982), comb. n. Original name Psammonyx longimerus;
Wecomedon minusculus (Gurjanova, 1938), comb. n. Original name Paratryphosites minusculus;
Wecomedon nobilis (Stimpson, 1853), comb. n. Original name Anonyx nobilis;
Wecomedon similis Jarrett & Bousfield, 1982, comb. n. Original name Wecomedon similis;
Wecomedon terranovae (Steele, 1979), comb. n. Original name Psammonyx terranovae;
Wecomedon tzvetkovae (Budnikova, 2005), comb. n. Original name Psammonyx tzvetkovae;
Wecomedon wecomus (J.L. Barnard, 1971), comb. n. Original name Hippomedon wecomus;
Wecomedon wirketis (Gurjanova, 1962), comb. n. Original name Hippomedon wirketis.