Campylaimus inaequalis Cobb, 1920

Holovachov, Oleksandr, 2019, New and known species of the genus Campylaimus Cobb, 1920 (Nematoda: Araeolaimida: Diplopeltidae) from North European marine habitats, Biodiversity Data Journal 7, pp. 46545-46545 : 46545

Campylaimus inaequalis Cobb, 1920

Materials

Type status: Other material. Occurrence: catalogNumber: SMNH-177115 ; individualCount: 1; sex: female; Location: waterBody: Skagerrak; country: Sweden; locality: Bratten ; minimumDepthInMeters: 25; maximumDepthInMeters: 50; verbatimLatitude: 58°22,20'N; verbatimLongitude: 11°09,26'E; Identification: identifiedBy: Oleksandr Holovachov; dateIdentified: 2018; Event: year: 2011; month: 8; day: 9; habitat: Muddy sand Type status: Other material. Occurrence: catalogNumber: SMNH-177116 ; individualCount: 1; sex: female; Location: waterBody: Skagerrak; country: Sweden; locality: Gullmarsfjord, Klubban ; verbatimLatitude: 58°15,03'N; verbatimLongitude: 11°27,54'E; Identification: identifiedBy: Oleksandr Holovachov; dateIdentified: 2018; Event: year: 2014; month: 8; day: 14; habitat: Shells, gravel, sand, mud Type status: Other material. Occurrence: catalogNumber: SMNH-177117 ; individualCount: 1; sex: female; Location: waterBody: Skagerrak; country: Sweden; locality: Gullmarsfjord, Klubban ; verbatimLatitude: 58°15,03'N; verbatimLongitude: 11°27,54'E; Identification: identifiedBy: Oleksandr Holovachov; dateIdentified: 2018; Event: year: 2014; month: 8; day: 14; habitat: Shells, gravel, sand, mud Type status: Other material. Occurrence: catalogNumber: SMNH TYPE-9205 (same slide as C.triclados) ; individualCount: 1; sex: male; Location: waterBody: Skagerrak; country: Sweden; locality: Gullmarsfjord, near Fiskebaeckskil ; minimumDepthInMeters: 30; maximumDepthInMeters: 30; verbatimLatitude: 58°15,25'N; verbatimLongitude: 11°27,30'E; Identification: identifiedBy: Oleksandr Holovachov; dateIdentified: 2018; Event: year: 2011; month: 8; day: 11; habitat: Soft mud

Description

Measurements. Table 5 . Adult. Figs 24 , 25. Cuticle without longitudinal striation. Space between dorsal and ventral limbs of amphid not developed. Lateral alae narrow, with straight margins. It originates at posterior end of ventral limb of amphid and ends along posterior third of the tail. Secretory-excretory pore opens posterior to cardia, at level with anterior part of intestine. Tail with clavate terminal part. Male. Anteriormost edge of amphid positioned anterior to oral opening. Dorsal limb of amphid extends for a short distance posteriorly, equal to 2.3 labial region diameters in length. Ventral limb of amphid extends along pharyngeal region to level of mid-pharynx; 1.7 times the length of dorsal limb. Ventral limb of amphid two times wider than dorsal limb. Spicules with rounded manubrium and conoid, arcuate shaft. Gubernaculum platelike, without apophysis. One small precloacal papilliform sensillum located on 5th annule anterior to cloacal opening. Second precloacal pore-like sensillum located on 8th annule anterior to cloacal opening. Two pairs of ventrosublateral setae located along posterior half of tail and one pair of sublateral setae located subterminally. Female. Anteriormost edge of amphid positioned anterior to oral opening. Dorsal limb of amphid extends for a short distance posteriorly, equal to 1.9-2.0 labial region diameters in length. Ventral limb of amphid extends along pharyngeal region to level of midpharynx; 2.0-2.3 times the length of dorsal limb. Ventral limb of amphid two times wider than dorsal limb. Vagina straight. One pair of ventrosublateral setae located along middle of tail and one pair of dorsosublateral setae located subterminally.

Diagnosis

Body 0.53-0.64 mm long; cuticle without longitudinal striation; anteriormost edge of amphid anterior to oral opening; dorsal limb of amphid equal to 2.3 labial region diameters in male, 1.9-2.0 labial region diameters in female; ventral limb of amphid extends towards mid-pharynx in both sexes, 1.7 times the length of dorsal limb in male and 2.0-2.3 times the length of dorsal limb in female; ventral limb of amphid is twice as wide as dorsal limb; interamphideal space absent; secretory-excretory pore opens posterior to cardia; spicules 24 µm long; precloacal supplements indistinct; tail equal to 4.5-5.8 anal body diameters in length, with clavate terminal part.

Taxon discussion

The original description of C. inaequalis is detailed and well illustrated ( Cobb 1920), although without most of the morphometric characters which are currently considered important. The identification of recent specimens is based on the combination of the following two morphological features: ventral limb of the amphid is roughtly twice (1.7-2.3) as long as the dorsal limb and clavate terminal part of the tail. Specimens described by Vitiello (1970) under the name Campylaimus cf. inaequalis cannot be identified to any known species because of the unclear description of the amphid given in the text of an article, in particular the length of the ventral amphideal limb cannot be deduced from either the drawings or the text.

Figures

Figure 24. Campylaimus inaequalis Cobb, 1920 (scale bars = 20 µm, PIJ = pharyngo-intestinal junction / cardia, EP = secretory-excretory pore): a: female tail; b: female pharyngeal region; c: male pharyngeal region; d: male caudal region.