N.B.: the synonymy with Savignia Blackwall, 1833, proposed by Breitling, 2021: 22, was not followed here, as based mainly on COI (see FAQ 7); the validity of Diplocephalus is confirmed by Frick, Sanz-LaParra & Kropf, 2026: 104; considered a senior synonym of Prosoponcus Simon, 1884a: 569 [urn:lsid:nmbe.ch:spidergen:05362] (type Walckenaeria cristatus Blackwall, 1833) by Simon, 1894a: 656; considered a senior synonym of Plaesiocraerus Simon, 1884a: 745 [urn:lsid:nmbe.ch:spidergen:05364] (type Walckenaera latifrons O. Pickard-Cambridge, 1863) (itself not a senior synonym of Monocephalus Smith, 1906), of Streptosphaenus Simon, 1926: 384, 497 [urn:lsid:nmbe.ch:spidergen:05365] (type Diplocephalus adjacens O. Pickard-Cambridge, 1903 = D. connatus Bertkau, 1889) by Denis, 1949a: 140, of Chocorua Crosby & Bishop, 1933b: 164 [urn:lsid:nmbe.ch:spidergen:05363] (type Lophocarenum cuneatum Emerton, 1909 = Diplocephalus subrostratus (O. Pickard-Cambridge, 1873)) by Hackman, 1954: 28 and of Hemistajus Schenkel, 1934 (revalidated by Frick, Sanz-LaParra & Kropf, 2026: 114) by Thaler, 1970: 256.

Transferred to other genera:

Diplocephalus adjacens O. Pickard-Cambridge, 1904 -- see Erigonella

Diplocephalus antepenultimus (O. Pickard-Cambridge, 1882) -- see Tapinocyboides

Diplocephalus barbatus (L. Koch, 1879) -- see Hemistajus

Diplocephalus barbiger (Roewer, 1955) -- see Hemistajus

Diplocephalus bihamatus (Menge, 1868) -- see Erigonella

Diplocephalus buddebergi (Bösenberg, 1899) -- see Thyreosthenius

Diplocephalus connatus Bertkau, 1889 -- see Erigonella

Diplocephalus connatus jacksoni O. Pickard-Cambridge, 1904 -- see Erigonella

Diplocephalus cottoni La Touche, 1946 -- see Glyphesis

Diplocephalus curvicervix Denis, 1964 -- see Typhochrestus

Diplocephalus dentatus Tullgren, 1955 -- see Araeoncus

Diplocephalus diphyus Heimer, 1987 -- see Dactylopisthes

Diplocephalus eborodunensis (O. Pickard-Cambridge, 1875) -- see Araeoncus

Diplocephalus formosus (Banks, 1892) -- see Eridantes

Diplocephalus fuscipes (Blackwall, 1836) -- see Monocephalus

Diplocephalus fuscipes castaneipes (Simon, 1884) -- see Monocephalus

Diplocephalus helleri (L. Koch, 1869) -- see Araeoncus

Diplocephalus incertus (L. Koch, 1879) -- see Hemistajus

Diplocephalus latifrons (O. Pickard-Cambridge, 1863) -- see Erigonella

Diplocephalus leberti (Roewer, 1942) -- see Caracladus

Diplocephalus lobiceps (Banks, 1897) -- see Eridantes

Diplocephalus marijae Bosmans, 2010 -- see Araeoncus

Diplocephalus marusiki Eskov, 1988 -- see Hemistajus

Diplocephalus mirabilis Eskov, 1988 -- see Savignia

Diplocephalus montanus (Emerton, 1882) -- see Walckenaeria

Diplocephalus montanus Eskov, 1988 -- see Hemistajus

Diplocephalus obtusus Denis, 1952 -- see Araeoncus

Diplocephalus opacithorax (Simon, 1884) -- see Erigonella

Diplocephalus parvus (Banks, 1892) -- see Eridantes

Diplocephalus percisus (Keyserling, 1886) -- see Eridantes

Diplocephalus protuberans (O. Pickard-Cambridge, 1875) -- see Araeoncus

Diplocephalus pulicarius (Thorell, 1875) -- see Microctenonyx

Diplocephalus pygmaeus (Menge, 1869) -- see Tapinocyboides

Diplocephalus rostratus Schenkel, 1934 -- see Hemistajus

Diplocephalus saganus Bösenberg & Strand, 1906 -- see Diplocephaloides

Diplocephalus semiglobosus (Westring, 1861) -- see Entelecara

Diplocephalus tatricus (Kulczyński, 1882) -- see Araeoncus

Diplocephalus tauricus (Thorell, 1875) -- see Styloctetor

Diplocephalus tenellus (Bösenberg, 1899) -- see Tapinocyba

Diplocephalus wamotsus Chamberlin, 1919 -- see Hybauchenidium

Diplocephalus yasudai Saito, 1986 -- see Savignia

In synonymy:

Diplocephalus alpinus strandi Kolosváry, 1937 = Diplocephalus alpinus (O. Pickard-Cambridge, 1873) (Breitling et al., 2016b: 58)

Diplocephalus arvernus Denis, 1948 = Diplocephalus cristatus (Blackwall, 1833) (Bosmans & Oger, 2018: 54)

Diplocephalus bicephalus (Simon, 1884) = Diplocephalus cristatus (Blackwall, 1833) (Bosmans & Oger, 2018: 54)

Diplocephalus bicornis (Wider, 1834, T from Lophomma) = Diplocephalus cristatus (Blackwall, 1833) (Thorell, 1871a: 108, sub Erigone)

Diplocephalus brunneus (Bösenberg, 1902, T from Araeoncus) = Diplocephalus permixtus (O. Pickard-Cambridge, 1871) (Tullgren, 1955: 328)

Diplocephalus caespitum (C. L. Koch, 1841, T from Micryphantes) = Diplocephalus cristatus (Blackwall, 1833) (Thorell, 1871a: 108, sub Erigone)

Diplocephalus connectens Kulczyński, 1894 = Diplocephalus alpinus (O. Pickard-Cambridge, 1873) (Thaler, 1995b: D479, sub D. connectens)

Diplocephalus cristatus angusticeps Holm, 1973 = Diplocephalus cristatus (Blackwall, 1833) (Tanasevitch, 2011c: 138)

Diplocephalus cuneatus (Emerton, 1909) = Diplocephalus subrostratus (O. Pickard-Cambridge, 1873) (Eskov, 1988c: 23)

Diplocephalus dimidiatus (Denis, 1945) = Diplocephalus graecus (O. Pickard-Cambridge, 1873) (Denis, 1964c: 63)

Diplocephalus foraminifer (O. Pickard-Cambridge, 1875) = Diplocephalus cristatus (Blackwall, 1833) (Bosmans & Oger, 2018: 54)

Diplocephalus foraminifer thyrsiger (Simon, 1884) = Diplocephalus cristatus (Blackwall, 1833) (Bosmans & Oger, 2018: 54)

Diplocephalus maculifrons Kulczyński, 1926 = Diplocephalus subrostratus (O. Pickard-Cambridge, 1873) (Eskov, 1988c: 23)

Diplocephalus meticulosus (Simon, 1918, T from Entelecara) = Diplocephalus picinus (Blackwall, 1841) (Denis, 1949a: 136)

Diplocephalus morum (O. Pickard-Cambridge, 1894, T from Gongylidium) = Diplocephalus picinus (Blackwall, 1841) (O. Pickard-Cambridge, 1911b: 53)

Diplocephalus nuncius (Simon, 1882, T from Erigone) = Diplocephalus graecus (O. Pickard-Cambridge, 1873) (Simon, 1926: 512, sub Entelecara)

Diplocephalus picinus humiliceps (Denis, 1945) = Diplocephalus picinus (Blackwall, 1841) (Wiehle, 1960a: 515)

Diplocephalus rectiloba (Simon, 1884) = Diplocephalus cristatus (Blackwall, 1833) (Bosmans & Oger, 2018: 54)

Diplocephalus sabulicola Bosmans, 1996 = Diplocephalus mystacinus (Simon, 1884) (Bosmans, 2002: 22)

Diplocephalus spinosus Hull, 1901 = Diplocephalus permixtus (O. Pickard-Cambridge, 1871) (Jackson, 1907b: 404)

Homonym replaced:

Diplocephalus montanus Tanasevitch, 1989 -- see Diplocephalus montaneus Tanasevitch, 1992

Nomina dubia:

Diplocephalus alpinus subrufus Roșca, 1935: 245, f. 5-6 (mf, Romania) -- Fedoriak, Voloshyn & Moscaliuc, 2016: 86

Diplocephalus coniceps Strand, 1906b: 616 (m, Somalia) -- Scharff, 1990b: 144

Diplocephalus fallaciosus (Bertkau, in Förster & Bertkau, 1883: 229, pl. 3, f. 2, m, Germany, originally in Lophocarenum) -- Wiehle, 1960a: 514

Diplocephalus pullinus Simon, 1918b: 153 (m, France) -- Lecigne et al., 2022: 14