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7.13 Order Desmodorida De Coninck, 1965

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7.13 Order Desmodorida De Coninck, 1965 Alexei V. Tchesunov 7.13 Order Desmodorida De Coninck, 1965 Diagnosis . Chromadorea. Nematodes fixed with formol 7.13.1.1 Family Desmodoridae Filipjev, 1922 often look yellowish or brownish. Cuticle usually with Diagnosis : Desmodoroidea. Body cylindrical. Cuticle is distinct annulations, but in some species very finely distinctly annulated, without dots, but spines, fringes striated or even smooth; punctation may occur rarely. or longitudinal ornamentations may be present. No spe- Cephalic cuticle is often smooth. Anterior sensilla are cialized ambulatory setae at anterior and posterior body arranged in three separate circles, six inner labial papil- ends. Locomotion is sinuous, typical for nematodes. lae, six outer labial papillae and four cephalic setae. Six subfamilies: Desmodorinae Filipjev, 1922, Spirini- Amphideal fovea is ventrally coiled, usually oligo- or inae Gerlach & Murphy, 1965, Pseudonchinae Gerlach & unispiral. Cheilostom is equipped with twelve longitudi- Riemann, 1973, Stilbonematinae Cobb, 1936, Molgolaimi- nal ribs or rugae that, however, are not always distinct. nae Jensen, 1978, and Prodesmodorinae Lorenzen, 1981. There is a more or less pronounced dorsal tooth in the stegostoma, whereas subventral teeth are smaller or absent. Pharynx muscular, with more or less developed 7.13.1.1.1 Subfamily Desmodorinae Filipjev, 1922 posterior bulb. Ovaries are paired (rarely a single ante- rior ovary) and mostly antidromously reflexed (outstret- Diagnosis (after Decraemer & Smol 2006, Verschelde et al. ched in two families). Gubernaculum is usually devoid of 2006): Desmodoridae. Cuticle annulated except in head a dorsocaudal apophysis. region. Head region with thickened cuticle except in lip In the frame of the order, three first families are region and set off as a conspicuous cephalic capsule. closely related and, hence, are united in the superfa- Amphideal fovea generally not surrounded by striation mily Desmodoroidea Filipjev, 1922 (e.g., Lorenzen 1981), of body cuticle; may be located on a cuticularized plate. where specialized taxa Draconematidae and Epsilone- Buccal cavity mostly with distinct teeth. Pharyngeal bulb matidae are derived from relatively more generalized round to elongated. group Desmodoridae. Three other families are united Type genus: Desmodora de Man, 1889 in the superfamily Microlaimoidea Micoletzky, 1922; interrelationships between Microlaimidae, Aponchi- Genus Acanthopharyngoides Chitwood, 1936 idae and Monoposthiidae need further study. Family (Fig. 7.100 A) Richtersiidae retains an isolated position within Diagnosis (after Decraemer & Smol 2006): Desmodorinae. Desmodorida. Head capsule composed of joined plates. Subcephalic setae present. Amphideal fovea unispiral, located on a cuticularized plate. Buccal cavity cylindrical with a large 7.13.1 Superfamily Desmodoroidea dorsal tooth and two or more ventrosublateral teeth. Pha- ryngeal bulb elongate, i.e., half as long as the pharynx and Filipjev, 1922 tripartite. Male with mid-ventral row of papilloid precloa- cal supplements and a larger posterior-most supplement. Diagnosis : Desmodorida. Body cuticle annulated, never Number of species: 6 punctated. Two reflexed ovaries. Single anterior testis. Type species: Acanthopharyngoides scleratus Chitwood, 1936 Three families: Desmodoridae Filipjev, 1922, Draco- nematidae Filipjev, 1918 and Epsilonematidae Steiner, Genus Acanthopharynx Marion, 1870 (Fig. 7.100 B) 1927. ( = Xanthodora Cobb, 1920) The three families form a monophyletic group based Diagnosis : Desmodorinae. Head capsule unbroken. on the synapomorphy that only anterior testis is present Amphideal fovea unispiral, located on a cuticularized (Lorenzen 1981, 1994). Two of the three families, i.e., Epsi- plate. Buccal cavity cylindrical with a large dorsal tooth lonematidae and Draconematidae, are considered to be and possibly two or more ventrosublateral teeth. Pha- monophyletic. ryngeal bulb elongate, i.e., half as long as the pharynx Authenticated | [email protected] Download Date | 2/15/14 10:08 AM 400 7.13 Order Desmodorida De Coninck, 1965 C B A D E F G I H J L K Fig. 7.100: Desmodorinae, examples of genera. A, Acanthopharyngoides quintus (from Riemann & Schrage 1977, Abb. 1); B, Acanthopharynx distechei (from Decraemer & Coomans 1978, Fig. 2); C, Bolbonema longisetosum (from Jensen 1985, Fig. 14); D, Croconema otti (from Gourbault & Vincx 1990, Figs. 1, 2); E, Desmodora communis (from Platt & Warwick 1988, Fig. 141); F, Desmodorella tenuispiculum (from Boucher 1975, Fig. 7); G, Echinodesmodora axi (from Blome 1982, Abb. 22E, 23A); H, Metadesmodora spinulosa (from Wieser 1959, Fig. 47); I, Paradesmodora campbelli (from Gerlach 1963); J, Parallelocoilas dollfusi (from Boucher 1975, Fig. 3); K, Psammonema ovisetosum (from Verschelde & Vincx 1995, Figs. 1, 2); L, Pseudochromadora securis (from Verschelde et al. 2006, Fig. 7). Authenticated | [email protected] Download Date | 2/15/14 10:08 AM 7.13.1 Superfamily Desmodoroidea Filipjev, 1922 401 and tripartite. Male with mid-ventral row of pore-like or Type species: Desmodora communis (B ü tschli, 1874). papilloid precloacal supplements. Revised by Verschelde et al . (1998) Number of species: 13 Type species: Acanthopharynx Marion, 1870 Genus Desmodorella Cobb, 1933 (Fig. 7.100 F) Diagnosis (after Verschelde et al. 1998): Desmodorinae. Genus Bolbonema Cobb, 1920 (Fig. 7.100 C) Body cuticular annules ornamented with longitudinal Diagnosis (after Verschelde et al. 1998): Desmodorinae. rows of ridges or spines. Lateral alae absent. Head capsule Globular head capsule. Cephalic setae located posterior blunt or rounded. Amphideal fovea large and multispiral, to the amphideal fovea. Long and shorter somatic setae. located on the head capsule. Cephalic setae anterior to or Number of species: 2 at the level of the anterior edge of the amphideal fovea. Type species: Bolbonema brevicolle Cobb, 1920 Pharynx with rounded or only slightly prolonged terminal Bolbonema is assumed as a subgenus of Desmodora bulb. by Gerlach (1963a: 90) and reconsidered as a genus by Number of species: 12. Verschelde et al. (1998). Type species: Desmodorella cephalata Cobb, 1933. Desmodorella was reduced to a subgenus of Desmo- Genus Croconema Cobb, 1920 (Fig. 7.100 D) dora by Wieser (1954: 40) and reconsidered as a genus by (syn.: Aculeonchus Kreis, 1928; Bla Inglis, 1963; Xenodes- Verschelde et al. (1998). modora Wieser, 1951) Diagnosis (after Verschelde et al. 1998): Desmodo- Genus Echinodesmodora Blome, 1982 (Fig. 7.100 G) rinae. Cuticle thick, coarsely annulated and often orna- Diagnosis (after Blome 1982, Decraemer & Smol 2006): mented with ridges or spines. Head capsule long, labial Desmodorinae. Cuticle with annulation surrounding region separated by a sutura. Amphideal fovea located the cryptospiral amphideal fovea. Body with stout anteriorly on the head capsule. Numerous subcephalic spine-like somatic setae with, in between, numerous setae arranged in three or more circles. Buccal cavity irregularly arranged hair-like setae. No cephalic with prominent dorsal tooth and one or two small sub- helmet. Buccal cavity with a small dorsal tooth and two ventral teeth. minute ventrosublateral teeth. Precloacal supplements Number of species: 18 tubiliform. Type species: Croconema cinctum Cobb, 1920. Brood pro- Number of species: 3 tection is known for some species (Ott 1976, Gourbault & Type species: Echinodesmodora axi Blome, 1982 Vincx 1990). Croconema is assumed as a subgenus of Desmodora Genus Metadesmodora Schuurmans Stekhoven, 1942 (see Gerlach & Riemann 1973) and reconsidered as a genus (Fig. 7.100 H) by Verschelde et al. (1998). Diagnosis (after Decraemer & Smol 2006): Desmodorinae. Body cuticular annulation beginning posterior to amphi- Genus Desmodora de Man, 1889 (Fig. 7.100 E, deal fovea. No cephalic helmet. Amphideal fovea located 7.114 A – B) on a cuticularized plate. (syn.: Mastodex Steiner, 1921; Amphispira Cobb, 1920) Number of species: 2 Diagnosis (after Verschelde et al. 1998): Desmodorinae. Type genus: Metadesmodora amphidiscata Schuurmans Cuticular annulation from fine to coarse, without special Stekhoven, 1942 ornamentation, spines or alae. Cephalic capsule well- developed, smooth, often with small vacuoles in the inner Genus Paradesmodora Schuurmans Stekhoven, 1950 cuticle. Cephalic setae situated anterior to the amphideal (Fig. 7.100 I) fovea or at the level of the anterior ridge of the fovea. Amphi- Diagnosis (after Decraemer & Smol 2006): Desmodorinae. deal fovea cryptospiral to spiral in one-two turns, seldom Amphideal fovea partially surrounded by striated body loop-shaped. Subcephalic setae, if present, few in number cuticle and not situated on cuticularized plates. No cepha- and situated posterior to the fovea. Short somatic setae lic helmet. in six or eight longitudinal rows. Pharynx with terminal Number of species: 7 rounded bulb. Tail short conical to long conico-cylindrical. Type species: Paradesmodora cephalata Schuurmans Precloacal pore-like supplements may be present. Stekhoven, 1950 (considered species inquirendae by Number of species: 49 Wieser & Hopper 1967) Authenticated | [email protected] Download Date | 2/15/14 10:08 AM 402 7.13 Order Desmodorida De Coninck, 1965 Genus Parallelocoilas Boucher, 1975 (Fig. 7.100 J) Genus Sibayinema Swart & Heyns, 1991 (Fig. 7.101 B) Diagnosis (after Boucher, 1975): Desmodorinae. Four Diagnosis (after Swart & Heyns 1991, Verschelde et al. subcephalic setae inserted in a common circle with four 2006): Desmodorinae. Cuticle coarsely annulated,
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