
This is the fourth in a series of keys by the authors to the groups of the free-living marine nematodes. The purpose of these keys is to provide students and other interested persons with a tool to begin the identification of free-living marine nematodes. These keys, along with those provided by Tarjan (1980) and Platt and Warwick (1983), should provide a basis for the identification of the genera of free-living marine nematodes.
Hope and Murphy (1972), Gerlach and Riemann (1974), Andrassy (1976), Lorenzen (1981), and Inglis (1983) have published classifications of free-living marine nematodes. Platt and Warwick (1988) provided descriptions and figures for the species of chromadorids reported from Britain.
The key presented herein is not intended to reflect phylogenetic relationships. It includes 55 genera of free-living marine nematodes in the suborder Chromadorina, superfamily Chromadoroidea, exclusive of the family Chromadoridae.
Although the key follows the classification of Lorenzen (1981), Jensen (1979) and Platt (1982) should be consulted regarding the Comesomatidae and Ethmolaimidae. Jensen (1979) revised the Comesomatidae and provided keys to the subfamilies, genera, and species. Lorenzen (1981) recognized the family Neotonchidae. Platt (1982) revised the family Ethmolaimidae and included the neotonchids in the Ethmolaimidae as the subfamily Neotonchinae Wieser & Hopper, 1966. Platt (1982) provided keys to the subfamilies, genera, and species of the Ethmolaimidae. Platt and Warwick (1988) also included the neotonchids in the Ethmolaimidae but did not segregate taxa at the subfamily level.
Illustrations in the key were obtained from published references. In some cases, portions of the anatomy shown on the drawings are labeled or emphasized with ink; in other cases pertinent anatomical details have been deleted to better portray the structures of interest. Credit is given for each illustration used.
| a | amphid | m | mandible |
| bc | buccal cavity | ps | precloacal supplement |
| cs | cephalic sensilla | r | rugae |
| eb | esophageal bulb | rs | cervical sensilla |
| g | gubernaculum | s | spicule |
| ga | gubernacular apophysis | sp | small spines |
| lp | longitudinal punctations | ss | somatic sensilla |
| ls | labial sensilla | t | teeth |
1. Amphid a distinct spiral (Figs. 53a, 81a) . . . . . 2
1'. Amphid not a distinct spiral . . . . . Chromadoridae (not included)
2 (1). Anterior part of buccal cavity with 12 rugae (Fig. 13r); females with reflexed ovaries . . . . . 5
2'. Anterior part of buccal cavity without 12 rugae; females with outstretched ovaries . . . . . Comesomatidae . . . . . 3
3 (2). Posterior part of buccal cavity weakly cuticularized ; spicules short (2 anal body diameters or less) (Fig. 6s); gubernaculum with dorso-caudally directed apophyses (Fig. 4ga) . . . . . Sabatieriinae
4 (3). Posterior part of buccal cavity collapsed, weakly cuticularized (Fig. 19bc); teeth present or absent . . . . . Comesomatinae
5 (2). Amphid unispiral (Fig. 28a); buccal cavity elongate, not funnel-shaped (Fig. 108bc) . . . . . Ethmolaimidae
6 (5). Teeth mostly absent, mandibles present (Fig. 106m) or absent; if both teeth and mandibles absent, then cuticle with numerous longitudinal rows of small spines (Fig. 96sp) . . . . . Selachinematidae
6'. Teeth, if present, appear as a single dorsal tooth and two subventral teeth (Fig. 71t) or a single dorsal tooth (Fig. 36t). If teeth absent then buccal cavity not divided into cup-shaped and cylindrical parts; mandibles absent . . . . . 7
7 (6). Esophagus with posterior bulb; spicules typically bent about 2/3 distance from proximal end (Fig. 70s); male precloacal supplements well developed, cup-shaped . . . . . Neotonchidae
8 (7). Ten longitudinal alae present; cuticular punctations absent (Figs. 112, 113) . . . . . Xenocyatholaimus Gerlach, 1953
8'. Longitudinal alae absent; cuticular punctations present . . . . . 9
9 (8). Precloacal supplements present in male . . . . . 10
9'. Precloacal supplements absent in male . . . . . Cyatholaiminae (in part)
11 (10). Male precloacal supplements protrusible tubes (Fig. 2ps) or setose (Fig. 80ps) . . . . . Paracanthonchinae
| Figure No. | Genus | Illustration Source |
| 1-2 | Aconthonchus | Wieser 1955, p. 66, Figs. a, b |
| 3-4 | Actarjania | Hopper 1967, p. 141, Figs. 5, 7 |
| 5-6 | Biarmifer | Wieser 1954, p. 11, Figs. c, e |
| 7-8 | Cervonema | Gourbault 1980, p. 739, Figs. 1c, d |
| 9-10 | Cheironchus | Gerlach 1964a, p. 46, Figs. a, b |
| 11-12 | Choanolaimus | Riemann 1966, p. 133, Figs. 34a, c |
| 13-14 | Choniolaimus | Riemann 1966, p. 110, Figs. b, d |
| 15-16 | Cobbionema | Furstenberg & Heyns 1987, p. 81, Figs. 1, 4 |
| 17-18 | Comesoma | Wieser 1954a, p. 137, Figs. 177b, d |
| 19-20 | Comesomoides | Gourbault 1980, p. 747, Figs. 4a, c |
| 21-22 | Cyatholaimus | Wieser 1959, Pl. XV, Fig. 37a; Pl. XVI, Fig. 37b |
| 23-25 | Demonema | Gerlach 1958, Taf. 40, Figs. 1b, c, d |
| 26-27 | Dorylaimopsis | Schuurmans Stekhoven 1950, p. 147, Figs. 88A, I |
| 28-29 | Ethmolaimus | Jensen 1979, p. 165, Figs. 57, 58 |
| 30-31 | Filitonchoides | Jensen 1986, p. 253, Figs. 6B, E |
| 32-33 | Filitonchus | Platt 1982, p. 248, Figs. 36b, d |
| 34 | Gomphionchus | Wieser & Hopper 1966, p. 527, Figs. 20, 21 |
| 35 | Gomphionchus | Platt 1982, p. 217, Figs. 14a, b |
| 36-37 | Gomphionema | Wieser & Hopper 1966, p. 530, Figs. 31, 32 |
| 38-39 | Gammanema | Murphy 1964, p. 195, Fig. 3a; p. 196, Fig. 4 |
| 40-41 | Halichoanolaimus | Wieser & Hopper 1967, p. 324, Figs. 34A, 35B |
| 42-43 | Hopperia | Vitiello 1969, p. 486, Fig. 1b; p. 488, Fig. 2a |
| 44-45 | Kosswigonema | Gerlach 1964a, p. 45, Figs. 15a, e |
| 46-48 | Kraspedonema | Gerlach 1954, p. 100, Figs. 2b, c, d |
| 49-50 | Laimella | Hopper 1967, p. 144, Figs. 2, 3 |
| 51-52 | Latronema | Wieser 1954, p. 31, Figs. 109a, d |
| 53-54 | Longicyatholaimus | Vitiello 1970, p. 476, Figs. 18A, D |
| 55-56 | Marilynia | Hopper 1972, p. 75, Figs. 14, 15 |
| 57-58 | Metacomesoma | Wieser 1954, p. 137, Figs. 176a, c |
| 59-60 | Metacyatholaimus | Gerlach 1964b, p. 73, Figs. 2b, d |
| 61-62 | Metasabatieria | Timm 1961, p. 51, Figs. 35a, b |
| 63-64 | Minolaimus | Vitiello 1970, p. 486, Figs. 25b, f |
| 65-66 | Nannolaimoides | Ott 1972, p. 464, Figs. 4, 7 |
| 67-68 | Nannolaimus | Platt 1982, p. 242, Figs. 32b, d |
| 69-70 | Neotonchoides | Platt 1982, p. 238, Fig. 29c |
| 71-72 | Neotonchus | Platt 1982, p. 220, Figs. 16a, b |
| 73 | Paracanthonchus | Wieser & Hopper 1967, p. 323, Fig. 31a |
| 74 | Paracanthonchus | Inglis 1970, p. 7, Fig. 13 |
| 75-76 | Paracanthonchus | Wieser & Hopper 1967, p. 323, Figs. 31b, c |
| 77-78 | Paracomesoma | Jensen & Gerlach, 1977, p. 61, Figs. 1a, c |
| 79-80 | Paracyatholaimus | Wieser & Hopper 1967, p. 323, Figs. 32a, b |
| 81-82 | Paracyatholaimoides | Boucher 1976, p. 48, Figs. 7c, f |
| 83-84 | Paralongicyatholaimus | Warwick 1971, p. 101, Figs. 3a, d |
| 85-86 | Paramesonchium | Jensen 1976, p. 245, Figs. 30, 36 |
| 87-88 | Phyllolaimus | Murphy 1963, p. 76, Figs. 2A, C |
| 89-90 | Pierrichia | Vitiello 1970, p. 455, Figs. 3A, D |
| 91-92 | Pomponema | Wieser & Hopper 1967, p. 321, Figs. 28a, c |
| 93-95 | Praecanthonchus | Pastor de Ward 1979, p. 35, Figs. 5b,g, e |
| 96-97 | Richtersia | Soetaert & Vincx 1986, p. 129, Fig. 3b |
| 98-99 | Sabatieria | Wieser & Hopper 1967, p. 335, Figs. 59a, c |
| 100-101 | Scholpaniella | Sergeeva 1972, p. 1293, Figs. 5, 6 |
| 102-103 | Setosabatieria | Platt 1985, p. 43, Fig. 9 |
| 104-105 | Synonchiella | Riemann 1966, p. 135, Figs. 36a, d |
| 106-107 | Synonchium | Gerlach 1953, p. 556, Figs. 18a, c |
| 108-109 | Trichethmolaimus | Gerlach 1956, Taf. 31, Figs. a, b |
| 110-111 | Vasostoma | Wieser 1954a, p. 137, Figs. 175a, b |
| 112-113 | Xenocyatholaimus | Gerlach 1953, p. 74, Figs. 1a, c |
| 114-115 | Zyzzors | Inglis 1963, p. 545, Fig. 25 |
| Wieser & Hopper 1967, p. 322, Fig. 29 |
Authors: Armen C. Tarjan, University
of Florida, and Edwin J. Keppner
Drawings: See Alphabetical List of Genera and Illustrations Sources
Project Coordinator: Thomas R. Fasulo, University of Florida
Publication Number: EENY-82
Publication Date: August 1999
Copyright 1999, University of Florida
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