Campylaimus tkatchevi Tchesunov, 1978

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 tkatchevi Tchesunov, 1978

Materials

Type status: Other material. Occurrence: catalogNumber: SMNH-177075 ; individualCount: 1; sex: female; Location: waterBody: Skagerrak; country: Sweden; locality: Gullmarsfjord, near Fiskebaeckskil ; minimumDepthInMeters: 40; maximumDepthInMeters: 50; verbatimLatitude: 58°15,40'N; verbatimLongitude: 11°27,46'E; Identification: identifiedBy: O. Holovachov; dateIdentified: 2018; Event: year: 2010; month: 8; day: 21; habitat: Mud Type status: Other material. Occurrence: catalogNumber: SMNH-177094 ; individualCount: 1; 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-177096 ; individualCount: 1; sex: male; Location: waterBody: Skagerrak; country: Sweden; locality: Gullmarsfjord, near Fiskebaeckskil ; minimumDepthInMeters: 8; maximumDepthInMeters: 15; verbatimLatitude: 58°15,09'N; verbatimLongitude: 11°27,54'E; Identification: identifiedBy: O. Holovachov; dateIdentified: 2018; Event: year: 2011; month: 8; day: 11; habitat: Muddy sand Type status: Other material. Occurrence: catalogNumber: SMNH-177103 ; individualCount: 1; sex: female; Location: waterBody: Skagerrak; country: Sweden; locality: Bratten ; minimumDepthInMeters: 352; maximumDepthInMeters: 374; verbatimLatitude: 58°19,18'N; verbatimLongitude: 10°29,34'E; Identification: identifiedBy: O. Holovachov; dateIdentified: 2018; Event: year: 2012; month: 10; day: 10; habitat: Soft bottom Type status: Other material. Occurrence: catalogNumber: SMNH-177113 ; individualCount: 2; sex: 1 female, 1 male; Location: waterBody: Skagerrak; country: Sweden; locality: Bratten ; minimumDepthInMeters: 55; maximumDepthInMeters: 70; verbatimLatitude: 58°22,19'N; verbatimLongitude: 11°04,55'E; Identification: identifiedBy: O. Holovachov; dateIdentified: 2018; Event: year: 2011; month: 8; day: 9; habitat: Mud and clay Type status: Other material. Occurrence: catalogNumber: SMNH-177114 ; individualCount: 2; sex: female; 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-177117 ; individualCount: 1; sex: male; Location: waterBody: Skagerrak; country: Sweden; locality: Gullmarsfjord, Klubban ; verbatimLatitude: 58°15,03'N; verbatimLongitude: 11°27,54'E; Identification: identifiedBy: O. Holovachov; dateIdentified: 2018; Event: year: 2014; month: 8; day: 14; habitat: Shells, gravel, sand, mud Type status: Other material. Occurrence: catalogNumber: SMNH-177118 ; individualCount: 3; sex: 1 female, 2 juveniles; 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-177119 ; individualCount: 3; sex: 1 female, 2 males; 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-177120 ; individualCount: 1; sex: male; Location: waterBody: Skagerrak; country: Sweden; locality: Gullmarsfjord ; minimumDepthInMeters: 54; maximumDepthInMeters: 54; verbatimLatitude: 58°16,00'N; verbatimLongitude: 11°28,00'E; Identification: identifiedBy: O. Holovachov; dateIdentified: 2018; Event: year: 1976; month: 4; day: 12; habitat: Very fine sediment

Description

Measurements. Table 2 . Adult. Figs 6 , 7. Cuticle without longitudinal striation. Space between dorsal and ventral limbs of amphid not developed. Lateral alae broad, appearing externally as two crenate lines encompassing entire length of amphid. It originates at level with anterior edge of amphid, extends posteriorly as two lines parallel to and widely spaced from ventral limb of the amphid ( Fig. 7 c, d) and ends at level of posterior fourth of tail by merging with posterior end of ventral limb of amphid. Secretory-excretory pore opens posterior to cardia, at level with anterior part of intestine ( Fig. 7 f). Tail with clavate 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 2.1-2.6 labial region diameters in length. Ventral limb of amphid extends along entire body to terminal part of tail. Ventral limb of amphid is 1.7-2.0 times wider than dorsal limb. Spicules with rounded manubrium and conoid, arcuate shaft. Gubernaculum platelike, without apophysis. Precloacal supplements absent/indistinct. Two pairs of ventrosublateral setae located along posterior half of tail and one pair of sublateral setae located between posterior end of lateral alae and tail terminus. Female. Anteriormost edge of amphid positioned at level with oral opening. Dorsal limb of amphid extends for a short distance posteriorly, equal to 1.8-2.4 labial region diameters in length. Ventral limb of amphid extends along entire body to terminal part of tail. Ventral limb of amphid is 1.7-2.5 times wider than dorsal limb. Vagina straight ( Fig. 7 e). One pair of ventrosublateral setae located along middle of tail and one pair of sublateral setae located close to posterior end of lateral alae.

Diagnosis

Body 0.56-0.73 mm long; cuticle without longitudinal striation; anteriormost edge of amphid at level with oral opening; dorsal limb of amphid equal to 2.1-2.6 labial region diameters in male, 1.8-2.4 labial region diameters in female; ventral limb of amphid extends towards posterior fourth of tail in both female and male; ventral limb of amphid is 1.7-2.5 wider than dorsal limb; interamphideal space absent; secretory-excretory pore opens posterior to cardia; spicules 27-30 µm long; precloacal supplements indistinct; tail equal to 4.8-5.9 anal body diameters in length, with clavate terminal part.

Taxon discussion

In having relatively long dorsal branch of the amphid, broad ventral branch of the amphid and clavate tail, recent specimens are most similar to C. tkatchevi described from the Caspian Sea ( Tchesunov 1978), differing only in somewhat longer body (0.56-0.73 mm vs. 0.45-0.61 mm in the type population) and spicules (27-30 µm vs. 23 µm in the type population).

Figures

Figure 6. Campylaimus tkatchevi Tchesunov, 1978 (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.