type Aranea undata De Geer, 1778; gender masculine

In synonymy:
Platycryptus aureocomosus (Mello-Leitão, 1943, T from Naubolus) = Platycryptus magnus (G. W. Peckham & E. G. Peckham, 1894) (Galiano, 1981a: 11, sub Marpissa broadwayi).
Platycryptus broadwayi (G. W. Peckham & E. G. Peckham, 1894) = Platycryptus magnus (G. W. Peckham & E. G. Peckham, 1894) (Edwards, 2006: 210).
Platycryptus delus (Chamberlin & Ivie, 1936, T from Menemerus) = Platycryptus magnus (G. W. Peckham & E. G. Peckham, 1894) (Chickering, 1946: 44, sub Marpissa).

Metacyrba arizonensis Barnes, 1958: 42, f. 59-60, 63 (Dmf).
Platycryptus arizonensis Edwards, 2006: 209, f. 103-104 (m, T from Metacyrba).

Marptusa californica Peckham & Peckham, 1888: 81, pl. 1, f. 61, pl. 5, f. 61, pl. 6, f. 61 (Dmf).
Marpissa californica Peckham & Peckham, 1909: 482, pl. 39, f. 2, pl. 40, f. 2 (mf, S of Marpissa melanura and M. minor; M. melanura revalidated by Edwards, 2006: 210 and M. minor by Kraus, 1955b: 77).
Metacyrba californica Barnes, 1958: 39, f. 57-58, 61, 64, 68 (mf, T from Marpissa).
Platycryptus californica Hill, 1979: 215 (T from Metacyrba).
Platycryptus californicus Edwards, 2006: 209, f. 105-106 (m).

Marptusa magna Peckham & Peckham, 1894a: 87, pl. 8, f. 3 (Df).
Marptusa broadwayi Peckham & Peckham, 1894a: 89, pl. 8, f. 5 (Dmf) [urn:lsid:nmbe.ch:spidersp:034458].
Marpissa magna F. O. Pickard-Cambridge, 1901a: 250, pl. 22, f. 3-4 (f).
Marpissa broadwayi Simon, 1901a: 603.
Menemerus delus Chamberlin & Ivie, 1936a: 30, pl. 8, f. 63 (Df) [urn:lsid:nmbe.ch:spidersp:060519].
Naubolus aureocomosus Mello-Leitão, 1943b: 264 (Df) [urn:lsid:nmbe.ch:spidersp:060518].
Marpissa magna Chickering, 1946: 44, f. 23-26 (Dm, f, S of Menemerus delus).
Marpissa broadwayi Galiano, 1981a: 11 (S of Naubolus aureocomosus).
Platycryptus broadwayi Edwards, Rinaldi & Ruiz, 2005: 23, f. 19-20, 51 (mf, T from Marpissa).
Platycryptus magnus Edwards, 2006: 210, f. 109-114 (mf, T from Marpissa, S of Platycryptus broadwayi).

Aranea undata De Geer, 1778: 320, pl. 39, f. 8 (D).
Aranea lurida Olivier, 1789: 22 (D).
Attus cunctator Walckenaer, 1837: 433 (Df).
Attus milberti Walckenaer, 1837: 433 (Df).
Attus undatus Walckenaer, 1837: 463 (Df).
Attus lentus Walckenaer, 1837: 466 (Df).
Attus familiaris Hentz, 1846: 354, pl. 21, f. 7 (Df).
Attus rupicola Hentz, 1846: 357, pl. 21, f. 14 (Df; N.B.: considered a nomen dubium by Edwards, 2004: 4).
Marpissa undata C. L. Koch, 1846: 60, f. 1127 (f).
Marpissa conspersa C. L. Koch, 1846: 61, f. 1128 (Dm).
Marpissa varia C. L. Koch, 1846: 69, f. 1134 (Df).
Salticus sundevalli Blackwall, 1846a: 37 (Dmf).
Dendryphantes undatus Simon, 1864: 314.
Dendryphantes conspersa Simon, 1864: 314.
Dendryphantes varia Simon, 1864: 315.
Marptusa familiaris Peckham & Peckham, 1888: 80, pl. 1, f. 60, pl. 4, f. 60, pl. 5, f. 60 (mf).
Marptusa familiaris Emerton, 1891: 237, pl. 19, f. 3 (mf).
Marptusa rupicola Banks, 1892a: 79, pl. 4, f. 49 (f).
Marpissa familiaris F. O. Pickard-Cambridge, 1901a: 250, pl. 22, f. 1-2 (mf).
Marpissa undata Simon, 1901a: 595, 603, f. 722.
Marptusa familiaris Emerton, 1902: 61, f. 157 (f).
Marpissa undata Peckham & Peckham, 1909: 481, pl. 39, f. 1, pl. 40, f. 1 (mf).
Marpissa undata Comstock, 1912: 678, f. 749.
Marpissa undata Chickering, 1944: 167, f. 53-56 (mf).
Marpissa rupicola Bryant, 1945b: 189, pl. 15, f. 2 (f).
Marpissa undata Kaston, 1948: 454, f. 1636-1639, 1655-1656 (mf).
Metacyrba undata Barnes, 1958: 36, f. 55-56, 62, 65, 67, 69 (mf, T from Marpissa).
Metacyrba undata Shear, 1967: 14, f. 43-44 (m).
Platycryptus undata Hill, 1979: 215 (T from Metacyrba).
Metacyrba undata Oehler, 1980: 8, f. 54-59 (mf).
Platycryptus undatus Paquin & Dupérré, 2003: 200, f. 2239-2241 (mf).
Platycryptus undatus Edwards, 2006: 210, f. 107-108 (m).
Platycryptus undatus Prószyński, 2017b: 24, f. 7P, 10K (m).