Campylaimus siwaschensis Sergeeva, 1981

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 siwaschensis Sergeeva, 1981

Materials

Type status: Holotype. Occurrence: catalogNumber: SMNH-177089 ; individualCount: 1; sex: female; Location: waterBody: Baltic; country: Sweden; maximumDepthInMeters: 0.02; verbatimLatitude: 58°46,00'N; verbatimLongitude: 17°49,52'E; Identification: identifiedBy: O. Holovachov; dateIdentified: 2018; Event: year: 2011; month: 5; day: 26; habitat: Soft sediment

Description

Measurements. Table 2 . Adult. Figs 8 , 9. Cuticle without longitudinal striation. Space between dorsal and ventral limbs of amphid not developed. Lateral alae narrow, appearing externally as two straight lines encompassing entire length of amphid. It originates at level with anterior edge of amphid, extends posteriorly as two lines parallel and very close to ventral limb of amphid and ends at level of posterior fifth of tail ( Fig. 9 c) by merging with posterior end of ventral limb of amphid. Secretory-excretory pore opens posterior to cardia, at level with anterior part of intestine. Tail with clavate terminal part. Male. Not found. Female. Anteriormost edge of amphid positioned just posterior to oral opening. Dorsal limb of amphid extends for a short distance posteriorly, equal to 1.2 labial region diameters in length. Ventral limb of amphid extends along entire body to terminal part of tail. Ventral limb of amphid is 1.3 times wider than dorsal limb. Vagina straight. One pair of ventrosublateral setae located along middle of tail and one pair of dorsosublateral setae located half way between posterior end of lateral alae and tal terminus.

Diagnosis

Body 0.6 mm long; cuticle without longitudinal striation; anteriormost edge of amphid posterior to oral opening; dorsal limb of amphid equal to 1.2 labial region diameters in female; ventral limb of amphid extends towards posterior fifth of tail; ventral limb of amphid is 1.3 wider than dorsal limb; interamphideal space absent; secretory-excretory pore opens posterior to cardia; tail equal to 5.8 anal body diameters in length, with clavate terminal part.

Taxon discussion

This species was originally described from the Lake Syvash, based on a single female ( Sergeeva 1981). The original description has crucial disagreements between the text and the illustration of the species regarding the size of the dorsal amphideal limb: the text states that the dorsal limb of the amphid is 23.3 µm long, but the illustration shows it to be only around 12-13 µm long. Recent specimen collected in the Baltic is similar to the holotype female in most body measurements and specifically in relatively short dorsal amphideal limb (12-13 µm vs. 14 µm in recent specimen), if the illustration of the holotype is to be trusted.

Figures

Figure 8. Campylaimus siwaschensis Sergeeva, 1981 (c-d) and C. lefeverei Gerlach, 1956 (a-b) (scale bars = 20 µm, PIJ = pharyngo-intestinal junction / cardia, EP = secretory-excretory pore): a, c: female pharyngeal region; b, d; female tail.