Ceramonema Cobb, 1920

Leduc, Daniel, 2024, Four new free-living marine nematode species (Plectida: Ceramonematidae) and two new species records (Desmodorida: Desmodorinae) from Rangitāhua / Kermadec Islands, Aotearoa / New Zealand, European Journal of Taxonomy 970, pp. 138-174 : 142-145

Ceramonema Cobb, 1920

Ceramonema Cobb, 1920: 264 , fig. 48.

Ceramonemoides Haspeslagh, 1973: 264 .

Cyttaronema Haspeslagh ,, 1973: 176.

Proceramonema Tchesunov & Miljutina, 2002: 17 , figs 9–11.

Type species

Ceramonema attenuatum Cobb, 1920 .

Diagnosis (from Tchesunov & Miljutina 2002)

Body cuticle consists of 70–320 broad and thick annules. Annules equal or unequal in width. If unequal, their width increases gradually from first subcephalic annule to those near cardia; then annule width drops sharply and again increases gradually to broad anal annule; following annules on tail narrow gradually to terminal cone. Intracuticular vacuolisation in annules may be present. Annule zygapophyses present or absent. Six or eight longitudinal crests extended along body. Labial region not set off. Setose outer labial sensilla and cephalic setae arranged in two separate circles. Amphids loop-shaped, elongate or rounded.

Remarks

Tchesunov&Miljutina(2002) suggested to split the genus into two groups of species:one group comprising species with distinct zygapophyses and a second group comprising species with small / indistinct zygapophyses (as seen using light microscopy). The key to species of the genus Ceramonema provided by Tchesunov & Miljutina (2002) did not include the two species described by Bussau (1993), which are considered valid by Holovachov (2020). Three species were subsequently described by Holovachov et al. (2008), bringing the total number of valid species of Ceramonema described prior to this study to 23.

List of valid species of Ceramonema Cobb, 1920

Group 1: species with distinct zygapophyses C. africana Furstenberg & Vincx, 1993 C. algoensis Furstenberg & Vincx, 1993 C. attenuatum Cobb, 1920

C. carinatum Wieser, 1959

C. chitwoodi De Coninck, 1942

C. fluctuosum Tchesunov & Miljutina, 2002 C. kromensis Furstenberg & Vincx, 1993 C. pisanum Gerlach, 1953

C. racovitzai Andrássy, 1973

C. reticulatum Chitwood, 1936

C. salsicum Gerlach, 1956

C. taikoraha sp. nov.

C. taiora sp. nov.

C. undulatum De Coninck, 1942

C. yunfengi Platt & Zhang, 1982

Group 2: species with small / indistinct zygapophyses

C. altogolfi Holovachov, Tandingan De Ley, Mundo-Ocampo, Baldwin, Rocha-Olivares & De Ley, 2008

C. aureolum Bussau, 1993

C. filipjevi De Coninck, 1942

C. inguinispina Holovachov, Tandingan De Ley, Mundo-Ocampo, Baldwin, Rocha-Olivares & De Ley, 2008

C. manganum Bussau, 1993

C. marisalbi Tchesunov & Miljutina, 2002

C. mokievskii Tchesunov & Miljutina, 2002

C. nasobema Holovachov, Mundo-Ocampo, Tandingan De Ley & De Ley, 2008

C. rectum Gerlach, 1957

C. rhombus Andrássy, 1973

Key to species of Ceramonema Cobb, 1920 (Group 1 with distinct zygapophyses) (updated from Tchesunov & Miljutina 2002)

1. Body length> 700 µm ...................................................................................................................... 2

– Body length <700 µm, less than 90 body annules. Amphid small, about 8 µm long and 4 µm wide, or less .............................................................................................. C undulatum De Coninck, 1942

2. Body slender, ratio of a ≥ 80 ............................................................................................................. 3

– Body relatively stout, ratio of a ≤ 70 ................................................................................................ 4

3. Lip region elevated, cap-like, number of body annules 300–307 (male) or 315 (female) ................. ............................................................................................. C. algoensis Furstenberg & Vincx, 1993

– Lip region not elevated, number of body annules much greater in males (287) than in females (184– 186) .............................................................................................. C. yungfengi Platt & Zhang, 1982

4. Cephalic ratio> 1 .............................................................................................................................. 5

– Cephalic ratio <1 .................................................................................. C. racovitzai Andrássy, 1973

5. Intracuticular vacuolisation in body annules and/ or cephalic capsule present ................................ 6

– Intracuticular vacuolisation absent ................................................................................................. 13

6. Cephalic capsule without intracuticular vacuolisation ..................................................................... 7

– Cephalic capsule with intracuticular vacuolisation .......................................................................... 9

7. Cephalic capsule elongate and evenly wide throughout its length, cephalic ratio ≥ 1.5, cephalic setae 8–12 µm ............................................................................................................................................ 8

– Cephalic capsule tapering anteriorly, cephalic ratio about 1, cephalic setae 6–9 µm, 111–117 body annules ............................................................................................. C. chitwoodi De Coninck, 1942

8. Amphid 26 µm long or> 65% of cephalic capsule length, cephalic ratio> 2 ................................... ...................................................................................... C. fluctuosum Tchesunov & Miljutina, 2002

– Amphid about 16 µm long or less than 45% of cephalic capsule length, cephalic ratio about 1.5 .... .................................................................................................................. C. carinatum Wieser, 1959

9. Cephalic ratio> 1, cephalic setae ≤ 0.3 length of cephalic capsule ............................................... 10

– Cephalic ratio about 1, length of cephalic setae> 0.5 length of cephalic capsule ............................. ........................................................................................................... C. reticulatum Chitwood, 1936

10. Amphid loop-shaped, elongate, 16–26 µm long, tail cone ≥ 19 µm long .......................................11

– Amphid loop-shaped, shorter, 9–15 µm long, tail cone 14–15 µm long ............................................ .............................................................................................. C. africana Furstenberg & Vincx, 1993

11. Male without precloacal spine ........................................................................................................ 12

– Male with precloacal spine, wide cloacal annule formed by fusion of two contiguous annules, 119– 127 body annules, ratio of a = 32–36 ..................................................................... C. taiora sp. nov.

12. Body length 1380–1428 µm, ratio of a = 49–60, ratio of c = 7 ........................ C. taikoraha sp. nov.

– Body length = 960 µm, ratio of a = 38, ratio of c = 5 .............................. C. salsicum Gerlach, 1956

13. Cephalic ratio about 1.5 .................................................................................................................... 4

– Cephalic ratio about 1, amphid small (10 µm long), its anterior margin at level of cephalic setae, 213 body annules in male ........................................................ C. kromensis Furstenberg & Vincx, 1993

14. Amphid loop-shaped with equal branches, amphid length <0.3 cephalic capsule length, labial region protruded, body length about 1600 µm ..................................................... C. pisanum Gerlach, 1953

– Amphid loop-shaped, with unequal branches, amphid length> 0.5 cephalic capsule length, labial region not protruded, body length about 1100 µm .................................. C. attenuatum Cobb, 1920

Key to species of Ceramonema Cobb, 1920 (Group 2 with small or indistinct zygapophyses) (updated from Tchesunov & Miljutina 2002)

1. Perioral tube absent ........................................................................................................................... 2

– Perioral tube projecting 5–7 µm anterior to the lips. 121–134 body annules, pronounced sexual dimorphism in amphid shape with ventral branch extending to 55–80 th annule in males .................. ............................. C. nasobema Holovachov, Mundo-Ocampo, Tandingan De Ley & De Ley, 2008

2. Outer labial setae either ≤ 5 µm or ≥ 8 µm ....................................................................................... 3

– Outer labial setae about 6 µm long, slightly shorter than cephalic setae, body length 750–1200 µm, 86 body annules, ratio of a 30–40, small, loop-shaped amphids .......... C. manganum Bussau, 1993

3. Outer labial setae ≤ 5 µm .................................................................................................................. 4

– Outer labial setae ≥ 8 µm .................................................................................................................. 7

4. Body ≥ 700 µm long, body annules broad, 8–12 µm wide .............................................................. 5

– Body <600 µm long, with less than 100 narrow (2–7 µm wide) annules, cephalic ratio about 1.6 .. .............................................................................................................. C. filipjevi De Coninck, 1942

5. Cephalic ratio <1.2, amphids located mostly or completely within posterior half of cephalic capsule .............................................................................................................................................. 6

– Cephalic ratio = 1.3, female with small loop-shaped amphid located on anterior half of cephalic capsule ......................................................................................................... C. rectum Gerlach, 1957

6. 187–195 body annules, cephalic setae located about halfway down length of cephalic capsule ....... ................................................................................................................ C. rhombus Andrássy, 1973

– 120 body annules, cephalic setae located near anterior extremity of cephalic capsule ...................... ................................................................................................................... C aureolum Bussau, 1993

7. Cephalic ratio 1.1–1.6 ....................................................................................................................... 8

– Cephalic ratio> 2 .......................................................... C. mokievskii Tchesunov & Miljutina, 2002

8. Male without thorn-shaped precloacal projection ............................................................................ 9

– Male with thorn-shaped precloacal projection, fewer than 200 body annules, sexual dimorphism in amphid shape (unispiral in female, loop-shaped in male), double cloacal annule .... C. ininguispina Holovachov, Tandingan De Ley, Mundo-Ocampo, Baldwin, Rocha-Olivares & De Ley, 2008

9. Female with unispiral amphids, cephalic capsule with pores, regular cloacal annule, gubernaculum with apophysis .................................................................................................................. C. altogolfi Holovachov, Tandingan De Ley, Mundo-Ocampo, Baldwin, Rocha-Olivares & De Ley, 2008

– Female with loop-shaped amphids, cephalic capsule without pores, enlarged cloacal annule, gubernaculum without apophysis ................................... C. marisalbi Tchesunov & Miljutina, 2002