After

<==o Aspidosiphonidae Baird, 1868
   |--o Aspidosiphon Diesing, 1851 [Pseudoaspidosiphon Baird, 1868]
   |  |--o {Akrikos} Cutler & Cutler, 1989
   |  |  |-- A. (A.) albus Murina, 1967 [Akrikos hartmeyeri Wesenberg-Lund, 1957]
   |  |  |-- A. (A.) mexicanus (Murina, 1967) [Golfingia mexicana Murina, 1967; Aspidosiphon longirhynchus Cutler & Cutler, 1980]
   |  |  |-- A. (A.) thomassini Cutler & Cutler, 1979
   |  |  |-- A. (A.) venabulum Selenka & de Man, 1883
   |  |  `-- A. (A.) zinni Cutler, 1969
   |  |--o (Aspidosiphon) Diesing, 1851
   |  |  |-- A. (A.) elegans (Chamisso & Eysenhardt, 1821) [Sternaspis elegans Chamisso & Eysenhardt, 1821; Aspidosiphon ravus Sluiter, 1886; Aspidosiphon exilis Sluiter, 1886; Aspidosiphon spinosus Sluiter, 1902; Aspidosiphon brocki Augener, 1903; Aspidosiphon spinalis Ikeda, 1904; Aspidosiphon carolinensis Sati, 1935; Aspidosiphon homoyarium Johnson, 1964]
   |  |  |-- A. (A.) exiguus Edmonds, 1974
   |  |  |-- A. (A.) gosnoldi Cutler, 1981 [Aspidosiphon spinalis Cutler, 1973]
   |  |  |--o A. (A.) gracilis (Baird, 1868) [Pseudaspidosiphon gracile Baird, 1868]
   |  |  |  |-- A. (A.) g. gracilis (Baird, 1868) [Pseudaspidosiphon gracile Baird, 1868]
   |  |  |  `-- A. (A.) g. schnehageni Fischer, 1913
   |  |  |-- A. (A.) misakiensis Ikeda, 1904 [Aspidosiphon hartmeyeri Fischer, 1919; Aspidosiphon gerouldi ten Broeke, 1925; Aspidosiphon speculatus Saiz, 1886]
   |  |  |-- A. (A.) Mülleri Diesing, 1851 [Sipunculus scutatus Müller, 1844; Aspidosiphon clavatus Diesing, 1851; Sipunculus cochlearius Valenciennes, 1854; Lesinia farcimen Schmidt, 1854; Aspidosiphon eremita Diesing, 1859; Phascolosoma radiata Alder, 1860; Sipunculus heterocyathi McDonald, 1862; Aspidosiphon jukesii Baird, 1873; Aspidosiphon mirabilis Thiel, 1875; Aspidosiphon armatum Danielssen & Koren, 1880; Aspidosiphon tortus Selenka & Bülow, 1883; Aspidosiphon heteropsammiarum Bouvier, 1894; Aspidosiphon michelini Bouvier, 1894; Aspidosiphon corallicola Sluiter, 1902; Aspidosiphon imbellis Sluiter, 1902; Aspidosiphon inquilinus Sluiter, 1902; Aspidosiphon exhaustum Sluiter, 1912; Aspidosiphon pygmaeus Fischer, 1921; Aspidosiphon kovaleskii Murina, 1964; Aspidosiphon hispitrofus LiGreci, 1980]
   |  |  `-- A. (A.) spiralis Sluiter, 1902
   |  `--o (Paraspidosiphon) Stephen, 1964 
   |     |-- A. (P.) coyi de Quatrefages, 1865 [Phascolosoma truncatum Keferstein, 1867]
   |     |-- A. (P.) fischeri ten Broeke, 1925 [Aspidosiphon fischerti cubanus Murina, 1967]
   |     |-- A. (P.) laevis (de Quatrefages, 1865) [Aspidosiphon laeve de Quaterfages, 1865; Aspidosiphon  cumingii Baird, 1868; Aspidosiphon major Vaillant, 1871; Aspidosiphon klunzingeri Selenka & Bülow, 1883; Aspidosiphon gigas Sluiter, 1884; Aspidosiphon anuglatus Ikeda, 1904; Aspidosiphon speciosus Gerould, 1913; Aspidosiphon grandis Sati, 1939; Aspidosiphon pachydermatus Wesenberg-Lund, 1937; Aspidosiphon brasiliensis Cordero & Mello-Leitao, 1952; Aspidosiphon johnstoni Edmondsd, 1980; Aspidosiphon quatrefagei Saiz, 1984]
   |     |-- A. (P.) parvulus Gerould, 1913 [Aspidosiphon spinoso-scutatus Fischer, 1922]
   |     |-- A. (P.) planoscutatus Murina, 1968
   |     |-- A. (P.) steenstrupii Diesing, 1859 [Aspidosiphon fuscus Sluiter, 1881; Aspidosiphon speculator Selenka, 1885; Aspidosiphon semperi ten Broeke, 1925; Aspidosiphon makoensis Sati, 1939; Aspidosiphon trinidensis Cordero & Mello-Leitao, 1952; Aspidosiphon exostomum Johnson, 1964; Aspidosiphon ochrus Cutler & Cutler, 1979]
   |     `-- A. (P.) tenuis Sluiter, 1886 [Aspidosiphon levis Sluiter, 1886; Aspidosiphon ambonensis Augener, 1903; Aspidosiphon formosanus Sati, 1939; Aspidosiphon havelockensis Haldar, 1978]
   |--o Lithacrosiphon Shipley, 1902
   |  |--o L. cristatus (Sluiter, 1902) [Aspidosiphon cristatus Sluiter, 1902]
   |  |  |-- L. c. cristatus (Sluiter, 1902 [Aspidosiphon cristatus Sluiter, 1902; Aspidosiphon uniscutatus Ikeda, 1904; Lithacrosiphon kukenthali Fischer, 1922; Lithacrosiphon indicus Fischer, 1922; Lithacrosiphon odhneri Fischer, 1922; Lithacrosiphon alticornis ten Broeke, 1925; Lithacrosiphon portidis ten Broeke, 1925; Lithacrosiphon gurjanovae Murina, 1967]
   |  |  `-- L. c. lakshadweepensis Haldar, 1991
   |  `-- L. maldivensis Shipley, 1902
   `--o Cloeosiphon Grübe, 1868 [Loxosiphon de Quatrfages, 1865]
      `-- C. aspergillus (de Quatrefages, 1865) [Loxosiphon aspergillus de Quatrefages, 1865; Cloeosiphon mollis Selenka & Bülow, 1883; Cloeosiphon javanicum Sluiter, 1886; Cloesiphon japonicum Ikeda, 1904; Cloeosiphon carolinum Ikeda, 1904]

Reference(s):

Special thanks to:

Jos H. M. Dols, for gathering additional information and species of these animals.