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Fig. 2. Anterior and posterior body regions. A in Halanonchus scintillatulus sp. nov. from New Zealand and a review of the suborder Trefusiina (Nematoda: Enoplida)
No full textFig. 2. Anterior and posterior body regions. A. Simpliconema aenigmatodes Blome & Schrage, 1985. B. Marisalbinema galtsovae Tchesunov, 1990. Drawings modified from Blome & Schrage (1985) and Tchesunov (1990).Published as part of Leduc, Daniel, Zhao, Zeng Qi & Sinniger, Frederic, 2020, Halanonchus scintillatulus sp. nov. from New Zealand and a review of the suborder Trefusiina (Nematoda: Enoplida), pp. 1-45 in European Journal of Taxonomy 661 on page 8, DOI: 10.5852/ejt.2020.661, http://zenodo.org/record/388884
Fig. 3. Trefusialaimus idrisi Leduc, 2013 in Halanonchus scintillatulus sp. nov. from New Zealand and a review of the suborder Trefusiina (Nematoda: Enoplida)
No full textFig. 3. Trefusialaimus idrisi Leduc, 2013, ♀ (NIWA139242). A. Anterior body region. B. Cephalic region. C. Posterior body region. D. Reproductive system. Scale bars: A = 50 μm; B = 20 μm; C = 90 μm; D = 125 μm.Published as part of Leduc, Daniel, Zhao, Zeng Qi & Sinniger, Frederic, 2020, Halanonchus scintillatulus sp. nov. from New Zealand and a review of the suborder Trefusiina (Nematoda: Enoplida), pp. 1-45 in European Journal of Taxonomy 661 on page 20, DOI: 10.5852/ejt.2020.661, http://zenodo.org/record/388884
Figure 4. Trefusialaimus idrisi Leduc, 2013 in Halanonchus scintillatulus sp. nov. from New Zealand and a review of the suborder Trefusiina (Nematoda: Enoplida)
No full textFigure 4. Trefusialaimus idrisi Leduc, 2013, ♀ (NIWA139242), light micrographs. A. Optical crosssection of cephalic region showing buccal cavity, lips and pharynx. B. Surface view of cephalic region showing outer labial setae and amphid. C. Mid-body region showing intestine and sperm cells in pseudocoelom (arrows). Scale bars: A–B = 15 μm; C = 22 μm.Published as part of Leduc, Daniel, Zhao, Zeng Qi & Sinniger, Frederic, 2020, Halanonchus scintillatulus sp. nov. from New Zealand and a review of the suborder Trefusiina (Nematoda: Enoplida), pp. 1-45 in European Journal of Taxonomy 661 on page 21, DOI: 10.5852/ejt.2020.661, http://zenodo.org/record/388884
Lauratonema Gerlach 1953
No full textGenus Lauratonema Gerlach, 1953 Diagnosis Lauratonematidae. Female gonad and intestine ending in the cloaca. Gubernaculum (when present) reduced, without apophyses. Ten species. Type species Lauratonema reductum Gerlach, 1953. Other valid species L. adriaticum Gerlach, 1953. L. dongshanense Chen & Guo, 2015. L. hospitum Gerlach, 1956. L. juncta Fadeeva, 1989. L. macrostoma Chen & Guo, 2015. L. mentulatum Wieser, 1959. L. obtusicaudatum Murphy & Jensen, 1961. L. pugiunculus Wieser, 1959. L. reniamphidum Hopper, 1961. Remarks A recent key to valid species of the genus was provided by Chen & Guo (2015).Published as part of Leduc, Daniel, Zhao, Zeng Qi & Sinniger, Frederic, 2020, Halanonchus scintillatulus sp. nov. from New Zealand and a review of the suborder Trefusiina (Nematoda: Enoplida), pp. 1-45 in European Journal of Taxonomy 661 on pages 11-12, DOI: 10.5852/ejt.2020.661, http://zenodo.org/record/388884
Porocoma Cobb 1920
No full textGenus Porocoma Cobb, 1920 Diagnosis (from Gerlach 1962 and Cobb 1920) Xennellidae. Cuticle annulated with longitudinal ridges. Cephalic capsule absent. Secretory excretory pore lies on a setiform elevation. Amphideal fovea horseshoe-shaped. Female reproductive system with two posterior ovaries, one of which extends anterior to vulva and folds posteriorly. Number and structure of male genital branch(es) unknown. Spicules short, arcuate. Tail conicocylindrical. One species. Type species Porocoma striata Cobb, 1920. Remarks This genus was considered closely related to Oxystomina by Wieser (1953), presumably due to the shape and arrangement of the cephalic sensilla, the minute buccal cavity and body shape. Porocoma was included in the Oxystominidae in the classification of Hope & Murphy (1972) but was later moved to the family Xennellidae by Lorenzen (1981) based on similarities with Xennella in the shape and arrangement of cephalic sensilla and presence of longitudinal cuticular ridges.Published as part of Leduc, Daniel, Zhao, Zeng Qi & Sinniger, Frederic, 2020, Halanonchus scintillatulus sp. nov. from New Zealand and a review of the suborder Trefusiina (Nematoda: Enoplida), pp. 1-45 in European Journal of Taxonomy 661 on pages 10-11, DOI: 10.5852/ejt.2020.661, http://zenodo.org/record/388884
Halanonchinae Wieser & Hopper 1967
No full textSubfamily Halanonchinae Wieser & Hopper, 1967 Diagnosis (modified from Wieser & Hopper 1967) Trefusiidae. Cuticle smooth or striated. Three lips, deeply incised in rare cases. Inner labial sensilla papillose or setose, outer labial setae and cephalic setae in separate circles, outer labial setae usually jointed. Amphideal fovea pocket-shaped, elongated, circular or unispiral. Buccal cavity without teeth; either small, funnel-shaped, not cuticularized (Rhabdocoma) or large, cylindrical/barrel-shaped with cuticularized walls (Africanema, Halanonchus). Male reproductive system diorchic with outstretched testes. Spicules short, arcuate or straight; gubernaculum present or absent, with or without apophyses; papillose precloacal supplements (complex supplements in H. bullatus Gerlach, 1964) present or absent. Female reproductive system with single posterior reflexed ovary. Remarks This subfamily is not monophyletic according to the SSU consensus tree (see Fig. 1). However, it is retained at least for now because Halanonchinae is unique within the Trefusiina in having a female reproductive system with a single posterior ovary.Published as part of Leduc, Daniel, Zhao, Zeng Qi & Sinniger, Frederic, 2020, Halanonchus scintillatulus sp. nov. from New Zealand and a review of the suborder Trefusiina (Nematoda: Enoplida), pp. 1-45 in European Journal of Taxonomy 661 on pages 19-22, DOI: 10.5852/ejt.2020.661, http://zenodo.org/record/388884
Simpliconematidae Blome & Schrage 1985
No full textFamily Simpliconematidae Blome & Schrage, 1985 Diagnosis (from Blome & Schrage 1985) Cuticle striated. Labial region divided into three lips. Cephalic sensilla with 6+10 arrangement; setose outer labial and cephalic sensilla. Circular amphideal fovea. Male reproductive system monorchic with anterior testis to the left of the intestine; sperm cell drop-shaped. Spicules slender, elongated; gubernaculum absent. Tail filiform. Females not known. Type genus Simpliconema Blome & Schrage, 1985. Remarks Simpliconema is characterized by cephalic and caudal regions similar to those of Marisalbinema Tchesunov, 1990 (family Xyalidae; Fig. 2), which was described after the treatment of the Trefusiida by Lorenzen (1981, 1994), while the long slender spicules are similar to those of Paramonohystera Steiner, 1916 (Xyalidae). More broadly, Simpliconema is characterized by features which resemble the Monhysterida more closely than the Trefusiina, including a circular amphideal fovea (within the Trefusiina, the amphideal fovea is circular only in some Trefusiidae genera, namely species of Cytolaimium, Trefusia, and Rhabdocoma), 6+10 arrangement of the anterior sensilla (usually 6+6 + 4 in the Trefusiina, except in the Lauratonematidae, Trefusialaimus and Tripylina), and the presence of only one anterior testis (usually two testes in Trefusiina, except some Lauratonematidae, Trefusialaimus, and Trischistomatidae). Blome & Schrage (1985) also noted differences with the Trefusiidae, such as the structure of the sperm (drop-shaped vs elongated in the Trefusiidae) and differentiated vas deferens (vs undifferentiated in the Trefusiidae). It appears likely that the taxonomic placement of the Simpliconematidae will need to be updated. Morphological information on the structure of the female reproductive system should allow us to settle the placement of this genus.Published as part of Leduc, Daniel, Zhao, Zeng Qi & Sinniger, Frederic, 2020, Halanonchus scintillatulus sp. nov. from New Zealand and a review of the suborder Trefusiina (Nematoda: Enoplida), pp. 1-45 in European Journal of Taxonomy 661 on page 8, DOI: 10.5852/ejt.2020.661, http://zenodo.org/record/388884
Xennellidae De Coninck 1965
No full textFamily Xennellidae De Coninck, 1965 Diagnosis (emended from Lorenzen 1981) Cuticle annulated except in X. cephalata Cobb, 1920 where it is apparently smooth; longitudinal ridges on cuticle usually present. Amphideal fovea pocket-shaped, horseshoe-shaped or circular. Anterior sensilla arranged in a 6 +6+ 4 pattern; long, setose outer labial and cephalic sensilla of similar length. Tapering cephalic capsule present (Xennella) or absent (Porocoma); when present, cephalic capsule offset from rest of body by constriction, cuticular discontinuity and/or thickened cuticle. Buccal cavity minute, tubular, without teeth. Female reproductive system monodelphic (Xennella) or didelphic (Porocoma). Male reproductive system monorchic (at least in Xennella suecica Allgén, 1935); spicules short, arcuate; gubernaculum present or absent, precloacal supplements present or absent. Type genus Xennella Cobb, 1920. Remarks De Coninck (1965) erected the subfamily Xennellinae, which originally only contained the genus Xennella. He placed the subfamily within the family Dasynemellidae De Coninck, 1965, order Desmodorida De Coninck, 1965. The subfamily was later raised to family by Gerlach & Riemann (1973 /1974). The Xennellidae was placed within the Trefusiida by Lorenzen (1981) based on the pocket-shaped amphid and absence of metanemes. This classification was followed by De Ley & Blaxter (2004). Within the Enoplida, an annulated cuticle is found in the genus Cricohalalaimus Bussau, 1993 (Oxystominidae, suborder Ironina Siddiqi, 1983), and the Lauratonematidae (suborder Trefusiina) are characterized by a “distinctly striated” cuticle. A cephalic capsule is present only within the suborder Enoplina, which is formed by the muscles of the anterior end of the pharynx attaching to the body cuticle. In Xennella, there is no evidence of any attachment between the pharynx and the body cuticle; instead, the cephalic capsule appears to be formed solely by the thickening of the cuticle. This would suggest that this genus may be better placed within one of the marine chromadorean orders, instead of within the Enoplida. It is possible that the placement of Xennella and Porocoma will need to be updated in the future as more morphological and molecular data become available.Published as part of Leduc, Daniel, Zhao, Zeng Qi & Sinniger, Frederic, 2020, Halanonchus scintillatulus sp. nov. from New Zealand and a review of the suborder Trefusiina (Nematoda: Enoplida), pp. 1-45 in European Journal of Taxonomy 661 on page 9, DOI: 10.5852/ejt.2020.661, http://zenodo.org/record/388884
Trefusialaimus idrisi Leduc 2013
No full textTrefusialaimus idrisi Leduc, 2013 Table 1; Figs 3–4 Material examined NEW ZEALAND • 2 ♀♀; western Chatham Rise off the east coast of New Zealand’s South Island, Tangaroa voyage TAN0705, station 157, surface (0–5 cm) sandy silt sediments; 42.785º S, 176.715º W; depth 1029 m; 16 Apr. 2007; D. Leduc leg.; NIWA 139242. • 1 ♀; same collection data as for preceding; NNCNZ 3330. Description Female Body cylindrical, slender, tapering slightly towards anterior extremity, with slight golden colouration due to the presence of numerous round, ca 1 μm diameter, golden inclusions. Cuticle smooth. Cephalic region rounded, slightly set off from body due to thickened cuticle and constriction immediately posterior to cephalic setae. Three lips, each bearing two small, conical inner labial papillae. Six outer labial setae and four cephalic setae in one circle, all with single joint; cephalic setae slightly longer than outer labial setae (6–9 vs 7–10 μm). Sub-cephalic and somatic setae absent. Amphid pocket-shaped with transverse aperture, ca 6–9 μm wide by 2 μm high. Buccal cavity funnel-shaped, without teeth. Pharynx cylindrical, slightly wider posteriorly, completely surrounding buccal cavity. Nerve ring situated at 49– 66% of pharynx length. Secretory-excretory system not observed. Cardia small, surrounded by intestine. Numerous sperm cells are present throughout the pseudocoelom between pharynx and anus, as well as in the uterus. Reproductive system with two opposed and outstretched ovaries, both to the right or left of intestine. Vagina at about two thirds of body length from anterior. Tail long, ca 8–10% of total body length, narrow, gradually tapering, without setae; spinneret not observed. Remarks The female specimens described here agree well with the male specimen described from the central Chatham Rise (350 m depth) in the arrangement of anterior sensilla, size and position of the amphids, presence of numerous golden inclusions and tail shape. The female specimens, however, were characterized by longer bodies (5004–5947 vs 4539 μm) and shorter tails (cʹ = 18–21 vs 38). This is the first time that female Trefusialaimus specimens are described. The structure of the female reproductive system in this species, which consists of two opposed and outstretched ovaries, is unusual for the Enoplida, although it has been observed in Cytolaimium exile (Trefusiidae), and Mediolaimus Tahseen, Sultana, Khan & Hussain, 2012 and Rogerus Hoeppli & Chu, 1934 (Enoplida, family Rhabdolaimidae Chitwood, 1951). It is unclear how sperm had entered the pseudocoelom of the female specimens we observed; however, the same observation was made previously for a juvenile of the same species (Leduc 2013).Published as part of Leduc, Daniel, Zhao, Zeng Qi & Sinniger, Frederic, 2020, Halanonchus scintillatulus sp. nov. from New Zealand and a review of the suborder Trefusiina (Nematoda: Enoplida), pp. 1-45 in European Journal of Taxonomy 661 on page 19, DOI: 10.5852/ejt.2020.661, http://zenodo.org/record/388884
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