Pseudaraeolaimus Chitwood, 1951

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), European Journal of Taxonomy 383, pp. 1-21 : 12-14

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.

Figures

Fig. 4. Pseudaraeolaimus cylindricauda (Allgén, 1932) comb. nov. lectotype male (SMNH Type-3435). A. Anterior end. B. Posterior end. Scale bar = 20 µm.