Campylaimus striatus Boucher & Helleouet , 1977

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 striatus Boucher & Helleouet, 1977

Materials

Type status: Other material. Occurrence: catalogNumber: SMNH-177109 ; individualCount: 1; sex: male; Location: waterBody: Skagerrak; country: Sweden; locality: Gullmarsfjord, near Fiskebaeckskil ; minimumDepthInMeters: 44; maximumDepthInMeters: 44; verbatimLatitude: 58°15,63'N; verbatimLongitude: 11°27,72'E; Identification: identifiedBy: O. Holovachov; dateIdentified: 2018; Event: year: 2011; month: 8; day: 11; habitat: Soft mud Type status: Other material. Occurrence: catalogNumber: SMNH-177112 ; individualCount: 1; sex: female; Location: waterBody: Skagerrak; country: Sweden; locality: Gullmarsfjord, near Fiskebaeckskil ; minimumDepthInMeters: 30; maximumDepthInMeters: 39; verbatimLatitude: 58°15,13'N; verbatimLongitude: 11°27,31'E; Identification: identifiedBy: O. Holovachov; dateIdentified: 2018; Event: year: 2010; month: 8; day: 21; habitat: Mud Type status: Other material. Occurrence: catalogNumber: SMNH-177114 ; individualCount: 1; sex: male; Location: waterBody: Skagerrak; country: Sweden; locality: Gullmarsfjord, Kristineberg-Lysekil ; minimumDepthInMeters: 53; maximumDepthInMeters: 53; verbatimLatitude: 58°15,73'N; verbatimLongitude: 11°26,10'E; Identification: identifiedBy: O. Holovachov; dateIdentified: 2018; Event: year: 2014; month: 8; day: 14; habitat: Mud Type status: Other material. Occurrence: catalogNumber: SMNH TYPE-9206 (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 Type status: Other material. Occurrence: catalogNumber: SMNH TYPE-9208 (same slide as C.longispiculus) ; individualCount: 3; sex: female; Location: waterBody: Skagerrak; country: Sweden; locality: Bratten ; minimumDepthInMeters: 139; maximumDepthInMeters: 153; verbatimLatitude: 58°34,19'N; verbatimLongitude: 10°38,20'E; Identification: identifiedBy: Oleksandr Holovachov; dateIdentified: 2018; Event: year: 2012; month: 10; day: 12; habitat: Soft bottom

Description

Measurements. Table 5 . Adult. Figs 26 , 27, 28. Cuticle with distinct longitudinal striation. Space between dorsal and ventral limbs of amphid not developed. Lateral alae narrow, appearing externally as smooth uniform band with straight margins. It originates at posterior end of ventral limb of amphid and ends along posterior fifth of tail. Secretory-excretory pore opens posterior to cardia, at level with anterior part of intestine. Tail with digitate terminal part. Male. Anteriormost edge of amphid positioned at level with 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 anterior part of intestine; 8.3-9.5 times the length of dorsal limb. Ventral limb of amphid 1.7-2.5 wider than dorsal limb. Spicules with rounded manubrium and conoid, arcuate shaft. Gubernaculum platelike, without developed apophysis, but with proximal part bent caudally. Precloacal supplements indistinct/absent. Two pairs of ventrosublateral setae located along posterior half of tail and one pair of dorsosublateral setae located just posterior end of the lateral alae. Female. Anteriormost edge of amphid positioned at level with oral opening. Dorsal limb of amphid extends for a short distance posteriorly, equal to 1.8-2.6 labial region diameters in length. Ventral limb of amphid extends along pharyngeal region just anterior or just posterior to pharyngo-intestinal junction; 3.4-5.7 times the length of dorsal limb. Ventral limb of amphid 1-2 times wider than dorsal limb. Vagina straight. One pair of ventrosublateral setae located along middle of tail and one pair of sublateral setae located just posterior to end of lateral alae.

Diagnosis

Body 0.52-0.73 mm long; cuticle with longitudinal striation; anteriormost edge of amphid at level with oral opening; dorsal limb of amphid equal to 1.9-2.0 labial region diameters in male, 1.8-2.6 labial region diameters in female; ventral limb of amphid extends towards anterior part of intestine in male and towards pharyngo-intestinal junction in female, 8.3-9.5 times the length of dorsal limb in male and 3.4-5.7 times the length of dorsal limb in female; ventral limb of amphid is 1-2 wider than dorsal limb; interamphideal space absent; secretory-excretory pore opens posterior to cardia; spicules 26-27 µm long; precloacal supplements indistinct; tail equal to 4.6-5.7 anal body diameters in length, with digitate terminal part.

Taxon discussion

C. striatus is so far the only known species of the genus with distinctly striated cuticular annulation. Original description of this species is based on three males and two females (although only two males and one female were measured, Boucher and Helléouët (1977)) while recent population includes two males and four females. Both populations are similar in the morphology of the cuticle (presence of longitudinal striations), in the size and proportions of the amphid and presence of sexual dimorphism in amphid size (ventral limb of the amphid extends towards anterior part of the intestine in male and towards the pharyngo-intestinal junction in female). Type specimens are relatively larger (L = 0.83-0.89 mm vs. 0.52-0.73 mm), with longer cephalic setae (6-7 µm vs. 1-3 µm) and longer tail (144-154 µm, c' = 6.3-9.6 vs. 82-112 µm, c' = 4.6-5.7). Since no qualitative differences between the two populations can be found and since differences in morphometrics can be explained by georgaphical variability or difficulty in measuring (cephalic sensilla), both populations are herefore considered to be conspecific.

Figures

Figure 26. Campylaimus striatus Boucher & Helleouet, 1977 (scale bars = 20 µm, PIJ = pharyngo-intestinal junction / cardia, EP = secretory-excretory pore): a: female pharyngeal region; b: male pharyngeal region; c: male caudal region; d: female tail.