Genus Chromadorita Filipjev, 1922

The genus Chromadorita was established by Filipjev (1922) when the type species C. demaniana was described from males collected in Russia. Wieser (1954) synonymized Odontonema Filipjev, 1930 and Allgeniela Strand, 1934 with Chromadorita . In his key, Wieser (1954) transferred some species of Chromadora, Chromadorina, Hypodontolaimus, Odontonema, Prochromadorella and Spilophora to Chromadorita and described Chromadorita leptopharynx, ending up with 16 species at that time. Chromadorita inornata (Cobb, 1915) was not included in the key, but considered as dubious species. Its description was based in a single imature and badly preserved female in which characters such as amphids and cephalic setae could not be observed. Wieser (1954) also did not cite Chromadorita brevisetosa Gerlach, 1953; Chromadorita obliqua (Gerlach, 1953) and Chromadorita schuurmansstekhoveni Timm, 1952 . The species C. chitwoodi Wieser, 1954 is now accepted as Innocuonema tentabunda (de Man, 1890) . Gerlach & Riemann (1973) cited 22 valid species. The species C. norvegica is now accepted as Prochromadorella norwegica based on its cuticular pattern (Wieser, 1954). Subsequently, fourteen new species were described [ C. nana Lorenzen, 1973; C. mucrocaudata Boucher, 1976; C. fennica Jensen, 1979; C. deseadensis Pastor de Ward, 1984; C. nephramphida Blome, 1985; C. pallida Blome, 1985; C. ceratoserolis Lorenzen, 1986; C. inaequispiculata Dashchenko, 1989; C. abyssalis Bussau, 1993; C. dimeris Bussau, 1993; C. pentameris Bussau, 1993; C. humila (Baranova & Dashchenko, 1992); C.mirabilis Gagarin, 1993; C. arctica Gagarin, 1999; C. longispiculata Gagarin, 2012 and C. pygmaea Gagarin, 2012]. The last species, C. regabi, was described by Baldrighi et al. (2018), who also presented an identification key but did not include C. arctica and C. humila . This work considered C. abyssalis, C. dimeris and C. pentameris, described by Bussau (1993) in his PhD thesis, as valid but, despite their descriptions with good quality and widespread divulgence, they should be considered as nomena nuda following the International Code of Zoological Nomenclature. Dashchenko (1989) suggested the reinstation of Allgeniella and the species C. humila was described as Allgeniella humila by Baranova & Dashchenko (1992) but later descriptions of species in Chromadorita did not accept Allgeniella as valid. Furthermore, C. heterophya should be considered as species inquirendum due to its poor description (missing details of cuticle and dorsal tooth). Therefore, we recognize 33 valid species.

Considering the generic diagnoses, one of the characters of Chromadorita was the lack of lateral differentiation in the cuticle (Wieser, 1954; Pastor de Ward, 1984 and Lorenzen, 1986), but Platt & Warwick (1988) observed cuticle with lateral differentiation in Chromadorita tenuis (Schneider, 1906), suggesting that at least this species does not belong to Chromadorita . Moreover, Platt & Warwick (1988) pointed out the difficulty of distinguish some species of Chromadorita and Innocuonema . The authors presented these species (e.g. I. tentabunda and C. nana) as a complex of Chromadorita / Innocuonema, characterized by slightly elongated and angular cuticle punctations, the absence of precloacal supplements and a tail with a tip characteristically bent to the left and curved dorsally. We maintain C. nana in Chromadorita and I. tentabunda in Innocuonema, since the cuticle and the buccal cavity of Chromadorita and Innocuonema are different (Table 4). When comparing these characters in the polytomous key, Chromadorita is more similar to Neochromadora and Ptycholaimellus than to Innocuonema .

Diagnosis (modified from Tchesunov 2014): Cuticle with homogeneous ornamentation and slightly more pronounced punctuation at the level of lateral fields. Six small outer labial setae or papillae and four cephalic setae in separate circles. Two circles of labial setae are conspicuous in some species (e.g. C. abnormis, C. abyssalis, C. ceratoserolis and C. pharetra). Somatic setae may be present. Amphideal fovea transverse slit-like and loop shaped. Buccal cavity mostly with one dorsal and one or two ventrosublateral teeth, rarely one indistinct dorsal tooth only; sometimes tiny denticles may be present. Peribuccal pharyngeal tissue may be symmetrically swollen or with asymmetrical dorsal swelling anteriorly; posterior bulb single (absent in C. ceratoserolis). Males with or without precloacal supplements. It is a largely marine genus, but six species were recovered in brackish and freshwater habitats ( C. arctica, C. fennica, C. inornata, C. leuckarti, C. mirabilis and C. paetzoldi).

Number of valid species: 33

Genus Chromadorita Filipjev, 1922

Syn. Algeniella Strand, 1934

Odontonema Filipjev, 1930

VALID SPECIES

1. Chromadorita abnormis (Kreis, 1928) Wieser, 1954 (Barents Sea)

Syn. Chromadora abnormis Kreis, 1928

2. Chromadorita arctica Gagarin, 1999 (Arctic Sea, Vaygach Island)

3. Chromadorita brachypharynx (Allgén, 1932) Wieser, 1959 (New Zealand, Campbell Island)

Syn. Chromadora brachypharynx Allgén 1932

4. Chromadorita brevisetosa Gerlach, 1953 (Italy)

5. Chromadorita ceratoserolis Lorenzen, 1986 (Antarctic Sea)

6. Chromadorita demaniana Filipjev, 1922 (Black Sea)

7. Chromadorita deseadensis Pastor de Ward, 1984 (Argentina)

8. Chromadorita fennica Jensen, 1979 (Archipelago of Finland, Vitsand and Storfjärden)

9. Chromadorita gracilis (Filipjev, 1922) Wieser, 1954 (Black Sea)

Syn. Chromadorina gracilis Filipjev, 1922

10. Chromadorita guidoschneideri (Filipjev, 1929) Wieser, 1954 (Baltic Sea)

Syn. Odontonema guidoschneideri Filipjev, 1929

Allgeniella guidoschneideri (Filipjev, 1929) Gerlach, 1951

11. Chromadorita humila (Baranova & Dashchenko, 1992) (Sea of Japan) new combination

Syn. Allgeniella humila Baranova & Dashchenko, 1992

12. Chromadorita hyalocephala (Steiner, 1916) Filipjev, 1922 (Barents Sea)

Syn. Chromadora hyalocephala Steiner, 1916

13. Chromadorita inaequispiculata Dashchenko, 1989 (Japan Sea)

14. Chromadorita leptopharynx Wieser, 1954 (Southern Chile, the Magallanes area)

15. Chromadorita leuckarti (de Man, 1876) Filipjev, 1929 (Netherlands)

Syn. Chromadora leuckarti de Man, 1876

Spiliphera impatiens Cobb, 1888

Chromadora tyroliensis Stefanski, 1916

Euchromadora viridis sensu Micoletzky, 1922

Chromadora viridis sensu Micoletzky, 1923

16. Chromadorita longispiculata Gagarin, 2012 (Vietnam, South China Sea)

17. Chromadorita macrodonta (Crites, 1961) Gerlach & Riemann, 1973 (USA, Piver’s Island)

Syn. Allgeniella macrodonta Crites, 1961

18. Chromadorita minima (Kreis, 1929) Wieser, 1954 (France, Trebeurden)

Syn. Spiliphera minima Kreis, 1929

19. Chromadorita minor (Allgén, 1927) Wieser, 1954 (Tasmania, Brown River)

Syn. Hypodontolaimus minor Allgén, 1927

20. C hromadorita mirabilis Gagarin, 1993 (Sakhalin Island, Russia)

21. Chromadorita mucrocaudata Boucher, 1976 (France, Morlaix Bay)

22. Chromadorita mucrodonta (Steiner, 1916) Wieser, 1954 (Barents Sea)

Syn. Chromadora mucrodonta Steiner, 1916

Spilophorella mucrodonta (Steiner, 1916) Schuurmans-Stekhoven, 1935

Prochromadorella mucrodonta (Steiner, 1916) Chitwood, 1951

23. Chromadorita nana Lorenzen, 1973 (North Sea, Helgoland)

24. Chromadorita nephramphida Blome, 1985 (Ecuador, Archipelago of Galapagos)

25. Chromadorita obliqua (Gerlach, 1953) Wieser, 1954 (Mediterranean)

Syn. Allgeniella obliqua Gerlach, 1953

26. Chromadorita pachydema (Schneider, 1926) Wieser, 1954 (Gulf of Finland)

Syn. Chromadora pachydema Schneider, 1926

Odontonema pachydema (Schneider, 1926) Filipjev, 1930

Allgeniella pachydema (Schneider, 1926) Allgén, 1947

27. Chromadorita paetzoldi Meyl, 1960 (Germany, Hale)

Syn. Chromadorita gracilis Paetzold, 1958

Chromadorita paetzoldi Goodey, 1963

28. Chromadorita pallida Blome, 1985 (Ecuador, Archipelago of Galapagos)

29. Chromadorita pharetra Ott, 1972 (USA, North Carolina)

30. Chromadorita pygmaea Gagarin, 2012 (Vietnam, South China Sea)

31. Chromadorita regabi Baldrighi, Vanreusel, Zeppilli, Sandulli & Segonzac, 2018 (Gulf of Guinea) 32. Chromadorita schuurmansstekhoveni Timm, 1952 (USA, Chesapeake Beach)

33. Chromadorita tenuis (Schneider, 1906) Filipjev, 1922 (Sweden, Öresund)

Syn. Chromadora tenuis Schneider, 1906

Chromadorita leuckarti sensu Otto, 1936

SPECIES INQUIRENDA

1. Chromadorita heterophya (Steiner, 1916) Filipjev, 1922 (Barents Sea)

Syn. Chromadora heterophya Steiner, 1916

2. Chromadorita inornata (Cobb, 1915) Filipjev, 1930 (USA, Maple River and Bessey Creek)

Syn. Chromadora inornata Cobb, 1915

NOMENA NUDA

1. Chromadorita abyssalis Bussau, 1993 (SE Pacific, Peru Basin)

2. Chromadorita dimeris Bussau, 1993 (SE Pacific, Peru Basin)

3. Chromadorita pentameris Bussau, 1993 (SE Pacific, Peru Basin)