Acantholaimus Allgén, 1933

Venekey, Virag, Gheller, Paula F., Kandratavicius, Noelia, Cunha, Beatriz Pereira, Vilas-Boas, Ana Carolina, Fonseca, Gustavo & Maria, Tatiana F., 2019, The state of the art of Chromadoridae (Nematoda, Chromadorida): a historical review, diagnoses and comments about valid and dubious genera and a list of valid species, Zootaxa 4578 (1), pp. 1-67 : 48-49

Genus Acantholaimus Allgén, 1933

The genus Acantholaimus ( Figure 4 ) was established by Allgén (1933) in the family Comesomatidae Filipev, 1918 ; subfamily Acantholaiminae Gerlach & Riemann, 1973. Lorenzen (1994) placed Acantholaimus within the family Chromadoridae and synonymized the subfamily Acantholaiminae with Spilipherinae . Acantholaimus is an abundant and species-rich genus in deep-sea nematode communities. Several Acantholaimus species were described by Soetaert (1989) and Bussau (1993) in their PhD thesis and they were included in recent reviews made by Miljutin & Miljutina (2016) and Manoel et al. (2017). However, despite their descriptions being of good quality and widespread divulgence (and even redescriptions in case of some of these species), they should be considered as nomena nuda following the International Code of Zoological Nomenclature.

Diagnosis (modified from Manoel et al. 2017): Cuticle punctate, with transverse rows of dots; lateral differentiation may be present as enlarged dots arranged irregularly, or more sparsely, or in transverse or longitudinal rows. Head sensilla arranged in three circles, posterior two being almost at the same level and usually setiform (sometimes jointed). Anterior sensilla are often papilloid and indistinct. Somatic setae may be present or absent. Amphidial fovea large, round with interrupted posterior rim or nearly comma-shaped (spiral in one species). Buccal cavity armed with three or more solid teeth, teeth minute or large, often eversible. Spicules of a peculiar construction, flattened and strongly broadened proximally. Rod-shaped gubernaculum without apophysis and bifurcated at its distal end. Spermatozoa giant, pear-shaped, often structurally complex. No precloacal supplements. Tail long, filiform. Marine, mostly deep-sea.

Number of valid species: 38.

Genus Acantholaimus Allgén, 1933

Syn. Neochromadorina Kreis, 1963

VALID SPECIES

1. Acantholaimus akvavitus Gerlach, Schrage & Riemann, 1979 (SE Pacific, Peru Basin)

2. Acantholaimus arminius Gerlach, Schrage & Riemann, 1979 (SE Pacific, Peru Basin)

3. Acantholaimus arthrochaeta Miljutina & Miljutin, 2012 (NE tropical Pacific, Clarion-Clipperton Fracture Zone) 4. Acantholaimus barbatus Miljutina & Miljutin, 2012 (NE tropical Pacific, Clarion-Clipperton Fracture Zone) 5. Acantholaimus calathus Gerlach, Schrage & Riemann, 1979 (Chiloé Island, South Chile)

6. Acantholaimus cornutus Miljutina & Miljutin, 2012 (NE tropical Pacific, Clarion-Clipperton Fracture Zone) 7. Acantholaimus cyathibucca Vivier, 1985 (NE Atlantic, Bay of Biscay)

8. Acantholaimus elegans Jensen, 1988 (North Atlantic, Norway Sea)

9. Acantholaimus formosus Miljutina, Miljutin & Tchesunov, 2013 (SE Atlantic, Angola Basin) 10. Acantholaimus gathumai Muthumbi & Vincx, 1997 (Central Western Indian Ocean)

11. Acantholaimus geraerti Muthumbi & Vincx, 1997 (Central Western Indian Ocean)

12. Acantholaimus gigantasetosus Vivier, 1985 (NE Atlantic, Bay of Biscay)

13. Acantholaimus heipi Muthumbi & Vincx, 1997 (Central Western Indian Ocean)

14. Acantholaimus incomptus Vivier, 1985 (NE Atlantic, Bay of Biscay) 15. Acantholaimus invaginatum Muthumbi & Vincx, 1997 (Central Western Indian Ocean)

16. Acantholaimus iubilus Gerlach, Schrage & Riemann, 1979 (SE Pacific, Peru Basin)

17. Acantholaimus longisetosus Allgén, 1933 ( Norway, Trondheim fjord)

18. Acantholaimus longistriatus Gourbault & Vincx, 1985 (SE Atlantic, Walvis Ridge)

19. Acantholaimus macramphis Gourbault & Vincx, 1985 (SE Atlantic, Walvis Ridge)

20. Acantholaimus maks Gerlach, Schrage & Riemann, 1979 (SE Pacific, Peru Basin)

21. Acantholaimus marliae Manoel, Silva & Esteves, 2017 (Potiguar Basin, South Atlantic)

22. Acantholaimus megamphis Vivier, 1985 (NE Atlantic, Bay of Biscay)

23. Acantholaimus microdontus Gourbault & Vincx, 1985 (SE Atlantic, Walvis Ridge)

24. Acantholaimus minutus ( Vitiello, 1970) Gerlach, Schrage & Riemann, 1979 (Mediterranean, Gulf of Lion) Syn. Acantholaimus minima ( Vitiello, 1970) Gerlach, Schrage & Riemann, 1979

Spiliphera minima Vitiello, 1970

Spiliphera minuta Vitiello, 1972

25. Acantholaimus obviatus Vivier, 1985 (NE Atlantic, Bay of Biscay)

26. Acantholaimus polydentatus Gerlach, 1951 (Baltic Sea, Kiel Bay)

Syn. Acantholaimus ewensis Platt & Zhang, 1982

Acantholaimus pilosus ( Kreis, 1963) Hope & Murphy, 1972

27. Acantholaimus quadridentatus Jensen, 1985 (Central West Atlantic, Gulf of Mexico).

28. Acantholaimus quintus Gerlach, Schrage & Riemann, 1979 (SE Pacific, Peru Basin)

29. Acantholaimus robustus Miljutina & Miljutin, 2012 (NE tropical Pacific, Clarion-Clipperton Fracture Zone) 30. Acantholaimus septimus Gerlach, Schrage & Riemann, 1979 (SE Pacific, Peru Basin)

31. Acantholaimus setosus Vitiello, 1970 (Mediterranean, Gulf of Lion)

32. Acantholaimus sieglerae Miljutina & Miljutin, 2012 (NE tropical Pacific, Clarion-Clipperton Fracture Zone) 33. Acantholaimus skukinae Miljutina, Miljutin & Tchesunov, 2013 (SE Atlantic, Angola Basin) 34. Acantholaimus spinicauda ( Vitiello, 1970) Gerlach, Schrage & Riemann, 1979 (NE Atlantic, Bay of Biscay) Syn. Spiliphera spinicauda Vitiello, 1970

35. Acantholaimus tchesunovi Miljutina & Miljutin, 2012 (NE tropical Pacific, Clarion-Clipperton Fracture Zone) 36. Acantholaimus veitkoehlerae Miljutina & Miljutin, 2012 (NE tropical Pacific, Clarion-Clipperton Fracture Zone)

37. Acantholaimus vermeuleni Muthumbi & Vincx, 1997 (Central Western Indian Ocean)

38. Acantholaimus versheldi Muthumbi & Vincx, 1997 (Central Western Indian Ocean)

NOMENA NUDA

1. Acantholaimus aequisetosus Soetaert, 1989 (Mediterranean)

2. Acantholaimus aheneus Bussau, 1993 (SE Pacific, Peru Basin)

3. Acantholaimus angustus Bussau, 1993 (SE Pacific, Peru Basin)

4. Acantholaimus caecus Bussau, 1993 (SE Pacific, Peru Basin)

5. Acantholaimus coruscus Bussau, 1993 (SE Pacific, Peru Basin)

6. Acantholaimus crenatus Soetaert, 1989 (Mediterranean)

7. Acantholaimus effilatus Soetaert, 1989 (Mediterranean)

8. Acantholaimus filicaudatus Soetaert, 1989 (Mediterranean)

9. Acantholaimus mirabilis Soetaert, 1989 (Mediterranean)

10. Acantholaimus occultus Bussau, 1993 (SE Pacific, Peru Basin)

11. Acantholaimus pygmaeus Soetaert, 1989 (Mediterranean)

12. Acantholaimus tectus Bussau, 1993 (SE Pacific, Peru Basin)

13. Acantholaimus vasicola Soetaert, 1989 (Mediterranean)

Figures

FIGURE 4. Schematic representation of Harpagonchinae and Spilipherinae genera. The drawings aim to show head with buccal cavity and amphideal fovea and cuticle ornamentation (general pattern). For Harpagonchus, Harpagonchoides and Acantholaimus the copulatory apparatus is also presented. In all drawings the right side is the dorsal side of the nematode.