Main Content

The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Vejdovskyella

Vejdovskyella Michaelsen, 1903 (ref. ID; 1257, 3692, 5939, 6972, 7211)

Family Naididae (ref. ID; 1928, 5939, 7854)

Family Naididae: Subfamily Naidinae Lastockin, 1924 (ref. ID; 1257, 7211)

ref. ID; 1663

Body wall naked. Without proboscis. Hair setae present. Dorsal setae beginning on IV, V or VI. Capilliform setae of dorsal bundles with a series of prominent teeth. Rare species. (ref. ID; 1663)

ref. ID; 1923

Prostomium not elongated to form a proboscis. Dorsal hair setae serrate along one or both borders; 2 to 3 secondary annulations in each segments. (ref. ID; 1923)

ref. ID; 7211

Vejdovskyella comata (Vejd.) and V. intermedia (Bret.) have been primarily distinguished by the presence of eyes and the apparent beginning of dorsal setal bundles in segment V in the V. comata as opposed to the absence of eyes and origin of dorsal setae on VI in V. intermedia, and the presence of giant ventral setae in a few anterior segments of the latter. The situation was confused by the description of specimens resembling V. intermedia but lacking the giant setae (though these are sometimes missing in other naidid species in which they usually occur) and of forms resembling V. comata bearing giant setae. This appeared to create a situation in which the two species were connected by a series of intermediate forms and so they were synonymized by Brinkhurst and Jamieson (1971). A reassessment of this problem was possible following translation of Soviet literature (Cekanovskaya 1962), from which it is clear that V. macrochaeta Last. and V. comata grandisetosa Fin. both represent forms of V. comata with giant setae, and that their giant setae have only the usual single upper tooth. This clearly differentiates the giant setae from those of V. intermedia, in which the upper tooth is replaced by two or more thin teeth of equivalent length and thickness. Cekanovskaya (1962) contends that the ventral setae of V are missing in V. comata, which means that the dorsal setae begin in VI, as in V. intermedia, even though they appear to begin in V. While the ventral setae in V. intermedia become progressively reduced in size from II to V, they are always present in IV-V, and there is no distinct gap between the ventral setae of V and the next bundle in our specimens. In contrast, while the vental setae of II-IV in V. comata become reduced in size, those of IV may be presence or absent, but there is always a distinct gap where the setae of V should be. Our examination of the limited collection available to us shows that Cekanovskaya is correct, and that diagnostic keys should be amended to state that dorsal setal bundles first appear opposite the fourth ventral setae bundles in V. comata and opposite to the fifth ventral bundles in V. intermedia. This also means that V. macrochaeta Last. can be regarded as a synonym of V. comata even though the dorsal setae begin in VI rather than the generally supposed position in V of both V. comata and V. comata grandisetosa. All three also possess eyes. Details of the differences in serration of the hairs are obvious to us but have not been documented to date. (ref. ID; 7211)

Type species

Vejdovskyella comata (Vejdovsky, 1883) (ref. ID; 7211)
  1. Vejdovskyella comata (Vejdovsky, 1883) (ref. ID; 1257, 1663, 1861, 1923, 3692, 5939, 7211, 7854) reported year? (ref. ID; 1928)
  2. Vejdovskyella comata grandisetosa Fin. (ref. ID; 7211)
  3. Vejdovskyella hellei Brinkhurst (ref. ID; 5939)
    See; Specaria hellei (ref. ID; 7211)
  4. Vejdovskyella intermedia (Bretscher, 1896) (ref. ID; 1257, 3692, 5939, 7211)
  5. Vejdovskyella macrochaeta (Lastockin, 1921) (ref. ID; 3692, 5939)
  6. Vejdovskyella simplex Liang, 1958 (ref. ID; 5939, 6972, 7098, 7854)

Vejdovskyella comata (Vejdovsky, 1883) (ref. ID; 1257, 1663, 1861, 1923, 3692, 5939, 7211, 7854) reported year? (ref. ID; 1928)

Descriptions

V. comata feeds on sediment particles and benthic diatoms. (ref. ID; 1861)

This species had a pair of conspicuous eyes. The oesophagus is a simple tube, without any such swelling as Vejdovsky represents. (ref. ID; 1928)

Eyes normally present. Ventral setae of II long, those of III shorter, those of IV shorter still or absent, no ventral setae on V. Beyond VI ventral setae two or three per bundle. Giant ventral setae rarely present, in IV-IX at most (macrochaeta, gandisetosa), with a single thin upper tooth. Dorsal setae begin opposite the fourth ventral setal bundles (in VI). Hair setae with very large, thick lateral serrations in two rows, visible at 250x magnification, often curled back over the main shaft, hair setae with bifid tips. Now reported from Lake Washington, Mercer Island, Washington, March and October 1982. (ref. ID; 7211)

Vejdovskyella intermedia (Bretscher, 1896) (ref. ID; 1257, 3692, 5939, 7211)

Descriptions

No eyes. Ventral setae of II-V present but diminishing in size posteriad. Beyond VI ventral setae single. Giant ventral setae generally present in some or all bundles of VI-VIII, upper tooth thin but replicated. Dorsal setae from VI. Hair setae with large coarse lateral serrations visible at 400x magnification, set close to shafts, hair setae simply pointed. Comfirmed here for the Fraser River, British Columbia. (ref. ID; 7211)

Vejdovskyella simplex Liang, 1958 (ref. ID; 5939, 6972, 7098, 7854)

Descriptions

A single immature specimen was collected. Body surface with foreign matter adhering. Eye present. Dorsal chaetal bundles beginning in V, each consisting of 3-4 stout and simple pointed hairs with up to 290 µm long and 3-5 simple pointed needles with 54-60 µm in length. The dorsal hairs with long lateral serrations usually in two rows except at the proximal part. Ventral chaetae of II (100 µm long) and III (92 µm long) four per bundle, longer and straighter than those in middle and posterior segments, and the upper teeth thinner and about twice longer than the lower ones; those in IV and V wholly lost, and those in from VI on 2-3 per bundle, 70-84 µm long. No giant chaetae in ventral bundles. Stomachal dilatation in VII. (ref. ID; 7098)

Remarks

A specimen of this species was examined in Wuhan by R.O. Brinkhurst, and the major part of the original description can be confirmed. The tips of the hair chaetae are not bifid, as seen in V. comata (Vejdovsky, 1883) in North America but not in Japan (Ohtaka 1985). The ventral chaetae do appear to be curved proximally, in contrast to the statement in the original description. There are fewer dorsal chaetae than in V. comata; again the Japanese specimens have only 3-6, not 4-9, per bundle. A detailed comparison with V. comata is still required. (ref. ID; 6972)

The taxonomic relationship between widespread V. (V.) comata (Vejdovsky), V. (V.) intermedia (Bretscher) and Chinese V. (V.) simplex is unclear (Brinkhurst et al. 1990). We herein ascribe the present Lake Biwa specimen to V. (V.) simplex, because the number and length of every sort of chaetae agrees quite well with the original description by Liang (1958). In Japan, although another congener V. (V.) comata was reported from Hokkaido (Ohtaka 1985), Brinkhurst et al. (1990) pointed out that the specimens showed an intermediate condition between European V. (V.) comata and Chinese V. (V.) simplex. (ref. ID; 7098)