Canthocamptus Westwood, 1836

Novikov, Aleksandr & Sharafutdinova, Dayana, 2022, Revision of the genus Canthocamptus (Copepoda: Harpacticoida) with a description of a new species from the Lena River Delta (North-eastern Siberia), European Journal of Taxonomy 826 (1), pp. 33-63 : 53-54

Genus Canthocamptus Westwood, 1836

Table 3

Canthocamptus Westwood, 1836: 227 .

Baikalocamptus Borutzky, 1931: 281 .

Canthocamptus (Canthocamptus) Westwood, 1836 , syn. nov.

Canthocamptus (Baikalocamptus) Borutzky, 1931 , syn. nov.

Type species

Canthocamptus staphylinus (Jurine, 1820) .

Other species and subspecies

C. assimilis Kiefer, 1931 ; C. baikalensis Borutzky, 1931 ; C. bulbifer Borutzky, 1947 ; C. carinatus Shen & Sung, 1973 ; C. glacialis Lilljeborg, 1902 ; C. iaponicus Brehm, 1927 ; C. kitaurensis Kikuchi in Ishida & Kikuchi, 1999; C. kunzi Apostolov, 1969 ; C. latus Borutzky, 1947 ; C. longifurcatus Borutzky, 1947 ; C. macrosetifer Ishida in Ishida & Kikuchi, 1999; C. microstaphylinus s. str. Wolf, 1905; C. microstaphylinus monardi Roy, 1927 ; C. oregonensis M.S. Wilson, 1956 ; C. robertcokeri M.S. Wilson, 1958 ; C. sinuus Coker, 1934 ; C. staphylinoides Pearse, 1905 ; C. takkobuensis Ishida in Ishida & Kikuchi, 1999; C. vagus Coker & Morgan, 1940 ; C. verestschagini ( Borutzky, 1931) ; C. waldemarschneideri sp. nov.

Species nomen nudum (according to Lang 1948)

C. aloisianus Brehm, 1908 ; C. brunnthaleri Brehm, 1913 ; C. cavernarum Packard, 1879 ; C. elegantulus Fischer, 1860 ; C. linearis Dana, 1852 ; C. maoricus Brehm, 1928 ; C. mareoticus Fischer, 1860 ; C. mobilensis Herrick, 1887 ; C. tatricus Daday, 1897 .

Species inquirendae

C. aequipes Krichagin, 1877 ; C. bicolor Wilson C.B., 1932 ; C. borcherdingii Poppe, 1889 ; C. cingalensis (Brady, 1886) ; C. crenulatus Mrázek, 1901 ; C. dentatus Poggenpol, 1874 ; C. elaphoides Chappuis, 1924 ; C. finni Bourne, 1893 ; C. fontinalis Rehberg, 1880 ; C. hyperboreus Willey, 1925 ; C. laciniatus Douwe, 1911 ; C. longicaudatus Krichagin, 1877 ; C. longisetosus Daday, 1902 ; C. megalops Lilljeborg, 1902 ; C. northumbricoides Willey, 1925 ; C. rostratus Claus, 1863 ; C. stroemii Baird, 1850 ; C. subsalus Brady, 1895 ; C. tenuicaudis Herrick, 1884 ; C. virescens Dana, 1849 ; C. wiegoldi Brehm, 1923 ; C. willeyi Kiefer, 1925 .

Amended diagnosis

Canthocamptidae . Body semi-cylindrical. Rostrum short. Caudal rami cylindrical; setae IV and V usually long and pinnate. Female antennule 8-segmented; male antennule 10-segmented, haplocer with geniculation between segments 7 and 8. Antenna with allobasis, eXopod 1- to 2-segmented, with 4 setae. Mandible with well-developed gnathobase; palp 1- to 2-segmented. Maxilla with two endites; endopod 1-segmented. P1 with 3-segmented rami; first endopodal segment long, reaching about midlength of third eXopodal segment. P2–P3 with 3-segmented rami; P4 eXopod 3-segmented, endopod 2-segmented. Female P5 endopod with 6 setae, typically seta V small (eXcept in C. iaponicus ); eXopod short (l/w <2), with 5 setae, typically seta I small, equal to or shorter than outer setae (eXcept in C. iaponicus ). Male P2 endopod seXually dimorphic, ʻCanthocamptus-likeʼ ( Fig. 9A ), second and third segments fused, third segment without outer seta, on border between ancestral second and third segments with posterio-lateral cuticular process. Male P3 endopod typical for Canthocamptidae , with long apophysis with tip; third segment with 0, 1 or 2 setae. Male P4 endopod usually with modified finger-like outer seta (simple spine in C. latus , C. bulbifer , C. longifurcatus and C. verestschagini .) Male P5 endopod with 2 setae, outer seta much smaller than inner one, inner seta/outer seta length from 1.5 to 10, typically 3; eXopod with 5 or 6 setae; inner seta, if present, long, pectinate (absent in C. latus , C. bulbifer , C. longifurcatus and C. robertcokeri ).

Distribution

Species of this genus are widespread in the Holarctic, with special diversity in Asia, where 12 species occur along with the new species. Five of them are endemics of Lake Baikal. The findings of C. staphilinus in Borneo ( Spandl 1924) are most likely due to a misidentification. Thus, the range of all Canthocamptus covers the entire Holarctic, not going beyond its limits.

Remarks

Despite the up-to-date lists of K. Lang (1948) and J.B.J. Wells (2008), still has about 77 valid names occur in the genus Canthocamptus in the WoRMS database ( Walter & Boxshall 2021). Here we consider as Canthocamptus only those 22 species closely related to the type species, also establishing a new genus, Kikuchicamptus gen. nov., for the species closely related to Kikuchicamptus mirabilis (Sterba, 1968) comb. nov. This leaves 43 species out of the new definition of Canthocamptus , which is based on clear synapomorphies. These species belong to different lineages, some related to other freshwater genera such as Bryocamptus , Elaphoidella Chappuis, 1929 , Attheyella , etc. Therefore, the WoRMS database must be updated to include in Canthocamptus only the species listed in this publication, and the species included in Tables 4 and 5 must be treated as nomina nuda, junior synonyms or species inquirendae.

Figures

Fig. 9. Canthocamptus waldemarschneideri sp. nov., allotype, ♂ (KFU BP 544/2). A. P2. B. P3; small seta indicated by arrowhead. C. P4.