Pseudaraeolaimus Chitwood 1951
Creators: name: Holovachov, Oleksandr
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Nematoda
Chromadorea
Araeolaimida
Diplopeltidae
Pseudaraeolaimus

description: Genus Pseudaraeolaimus Chitwood, 1951
Type species
Pseudaraeolaimus perplexus Chitwood, 1951
Diagnosis (emended after Fonseca & Bezerra 2014)
Cuticle visually smooth or finely striated; striae without ornamentation. Lateral alae absent. Somatic sensilla present. Labial region rounded; lips fused. Inner and outer labial sensilla indistinct. Cephalic sensilla setiform; their bases located at the base of the labial region, anterior to amphidial fovea. Cervical (paramphidial) sensilla present, located at the level of the amphid and posterior to it. Deirid absent. Ocelli present or absent. Amphidial fovea loop-shaped (inverted U-shaped). Secretory-excretory system present; renette cell located opposite to the anterior part of intestine. Cuticularised secretory-excretory duct very short, opens to the exterior just posterior to cephalic setae bases. Oral opening apical. Buccal cavity small and undifferentiated, its lining is uniform with the lining of the pharynx. Pharyngeal tubes absent. Pharynx subdivided into anterior corpus and posterior postcorpus; corpus cylindrical, muscular, with evenly distributed myofilaments; postcorpus glandular; pharyngeal lumen uniform in thickness along the entire pharynx length; valves absent. Female reproductive system didelphic-amphidelphic with equally developed branches, ovaries outstretched. Vulva equatorial. Male reproductive system diorchic, anterior testis outstretched, posterior testis outstretched, with posteriorly reflexed terminal section of the germinal zone. Spicules symmetrical, arcuate; gubernaculum present. Precloacal sensillum present. Setae in caudal region of males arranged in subventral and subdorsal pairs along the tail. Three caudal glands present, their nuclei are incaudal. Spinneret present.
* – at an oblique angle to the body axis
** – at a straight angle to the body axis
*** – not available, females are unknown
Valid species
Pseudaraeolaimus cassidaigniensis (Vitiello, 1972) comb. nov.
= Diplopeltula cassidaigniensis Vitiello, 1972
Pseudaraeolaimus cylindricauda (Allgén, 1932) comb. nov.
= Diplopeltis cylindricauda Allgén, 1932
= Diplopeltula cylindricauda (Allgén, 1932)
Pseudaraeolaimus laminata (Vitiello, 1972) comb. nov.
= Diplopeltula laminata Vitiello, 1972
Pseudaraeolaimus perplexus Chitwood, 1951
Pseudaraeolaimus ocellatus Kito, 1981
Remarks
According to Tchesunov & Miljutina (2008), main diagnostic characters of the genus Pseudaraeolaimus include: terminal (apical) oral opening, amphidial fovea loop-shaped, stoma small undifferentiated, pharynx glandular in its posterior part, excretory pore close to anterior end, ovaries paired, gubernaculum without apophyses. In addition, both Pseudaraeolaimus perplexus and P. ocellatus have several pairs of strongly developed cervical setae. This last feature is also known in other genera of Diplopeltidae, such as Araeolaimus de Man, 1888, Diplopeltis Cobb in Stiles & Hassall, 1905, Metaraeolaimoides De Coninck, 1936 and Southerniella Allgén, 1932, but not in type species of the genus Diplopeltula, D. breviceps.
Nomenclatorial changes
1) Diplopeltula cassidaigniensis Vitiello, 1972 is transferred to the genus Pseudaraeolaimus based on presence of terminal oral opening, undifferentiated stoma, loop-shaped amphidial fovea, strongly developed cervical setae.
2) Diplopeltis cylindricauda Allgén, 1932 is transferred to the genus Pseudaraeolaimus based on presence of terminal oral opening, undifferentiated stoma, loop-shaped amphidial fovea, strongly developed cervical setae, excretory pore close to anterior end (Fig. 4).
3) Diplopeltula laminata Vitiello, 1972 is transferred to the genus Pseudaraeolaimus based on presence of terminal oral opening, undifferentiated stoma, loop-shaped amphidial fovea, strongly developed cervical setae.
Key to species of Pseudaraeolaimus Chitwood, 1951
See Table 3 for additional diagnostic characters.
1. Body 2 mm long; amphidial fovea with transverse striation .............................................................. ............................................................................................... P. laminata (Vitiello, 1972) comb. nov.
– Body shorter than 1.5 mm long; amphidial fovea without transverse striation ................................ 2
2. Ocelli present .................................................................................................. P. ocellatus Kito, 1981
– Ocelli absent ..................................................................................................................................... 3
3. Amphidial fovea a broad loop, less than 1.5 times long as it is wide ... P. perplexus Chitwood, 1951
– Amphidial fovea a narrow loop, more than 3 times long as it is wide ............................................. 4
* – not available, specimens of particular sex are unknown
4. Cervical setae short, only two pairs at level with amphidial fovea .................................................... ................................................................................... P. cassidaigniensis (Vitiello, 1972) comb. nov.
– Cervical setae long, two pairs at level with amphidial fovea and 4–5 pairs at level with midpharynx .................................................................... P. cylindricauda (Allgén, 1932) comb. nov.
description: Published as part of Holovachov, Oleksandr, 2017, Belgopeltula belgica (Vincx & Gourbault, 1992) gen. et comb. nov. and Mudwigglus micramphidium sp. nov. from the west coast of Sweden, and reappraisal of the genus Pseudaraeolaimus Chitwood, 1951 (Nematoda: Araeolaimida: Diplopeltidae), pp. 1-21 in European Journal of Taxonomy 383 (383) on pages 12-16, DOI: 10.5852/ejt.2017.383, http://zenodo.org/record/3839807