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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Nais

Nais O.F. Muller, 1773 (ref. ID; 1257, 3692, 6913, 6972, 7211)

Family Naididae (ref. ID; 1928, 5876, 5939, 6554, 7645, 7854)

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

Family Naididae: Subfamily Naidinae Lastockin emend. Nemec & Brinkhurst (ref. ID; 6972)

ref. ID; 1663

Body wall naked without proboscis. Hair setae present. Dorsal setae beginning behaind II. Eyes present. Needle setae distinctly different from ventral setae. Capilliform setae of dorsal bundles without teeth. (ref. ID; 1663)

ref. ID; 1923

Prostomium not elongated to form a proboscis. Dorsal setae not serrate along borders; without secondary annulations on segments. Eyes normally present, ventral setae of segments 2 to 5 mostly well differentiated from those of the more posterior segments. (ref. ID; 1923)
  1. Nais africana (ref. ID; 6580)
  2. Nais alpina Sperber, 1948 (ref. ID; 1257)
  3. Nais andina Cernosvitov, 1939 (ref. ID; 6554)
  4. Nais barbata O.F. Muller, 1773 (ref. ID; 1257, 1663, 1923, 3692, 5939, 7854)
    Syn; Nais obtusa (Gervais, 1838) in Southern, 1909 (ref. ID; 1257)
  5. Nais behningi Michaelsen, 1923 (ref. ID; 3692, 5939, 7854) reported year? (ref. ID; 1663)
  6. Nais borutzkii Sokol'skaja, 1964 (ref. ID; 6651, 7854)
  7. Nais bretscheri Michaelsen, 1899 (ref. ID; 3692, 7854) reported year? (ref. ID; 7098)
    See; Nais pardalis (ref. ID; 6972)
  8. Nais bretscheri var. iorensis Patar. (ref. ID; 6609)
  9. Nais christinae Kasprzak, 1973 (ref. ID; 6618) reported year? (ref. ID; 6609)
  10. Nais communis Piguet, 1906 (ref. ID; 1257, 1663, 1861, 1923, 3692, 6554, 6913, 7211, 7854) reported year? (ref. ID; 3446) reported author and year? (ref. ID; 5939), cf. communis Piguet, 1906 (ref. ID; 6972)
    Syn; Nais heterochaeta Benham, 1893 (ref. ID; 1257)
  11. Nais diaphana Gruithuisen, 1828
    See; Chaetogaster diaphanus (ref. ID; 3962)
  12. Nais diastropha Gruithuisen, 1828
    See; Chaetogaster diastrophus (ref. ID; 3962)
  13. Nais elinguis O.F. Muller, 1773 (ref. ID; 1257, 1663, 1923, 3692, 6554, 6913, 7211, 7854) reported year? (ref. ID; 1928, 3446) reported author and year? (ref. ID; 5939)
  14. Nais heterochaeta Benham, 1893 (ref. ID; 1257) reported year? (ref. ID; 1928)
    Syn; Nais communis in Southern (1909) (ref. ID; 1257)
  15. Nais inflata Liang, 1963 (ref. ID; 6651, 6972) reported year? (ref. ID; 6597)
  16. Nais iorensis Pataridze, 1957 (ref. ID; 3692)
  17. Nais josinae Vejdovsky, 1883
    See; Specaria josinae (ref. ID; 7211)
  18. Nais lastockini Sokolskaja, 1958 (ref. ID; 3692) or Sokol'skaya, 1958 (ref. ID; 6972)
  19. Nais magnaseta (ref. ID; 5939)
  20. Nais obtusa (Gerv.) (ref. ID; 1928)
  21. Nais pardalis Piguet, 1906 (ref. ID; 3692, 6554, 6972, 7854) reported year? (ref. ID; 1663) reported author and year? (ref. ID; 5939)
    Syn; Nais bretscheri Michaelsen, 1989: Chen, 1940 (ref. ID; 6972)
  22. Nais pseudobtusa Piguet, 1906 (ref. ID; 1257, 1663, 1923, 3692, 6913) or 1909 (ref. ID; 6618) reported year? (ref. ID; 3446, 4491) reported author and year? (ref. ID; 5939)
  23. Nais raviensis Stephenson, 1914 (ref. ID; 6580)
    See; Dero raviensis (ref. ID; 6554)
  24. Nais simplex Piguet, 1906 (ref. ID; 1257, 1663, 1861, 1923, 3692, 6554) reported author and year? (ref. ID; 5939)
  25. Nais stolci Hrabe, 1981 (ref. ID; 6618)
  26. Nais variabilis Piguet, 1906 (ref. ID; 1257, 1663, 1923, 2780, 3692, 6554, 6913, 7211, 7854) reported year? (ref. ID; 3446, 4491) reported author and year? (ref. ID; 5939)

Nais alpina Sperber, 1948 (ref. ID; 1257)

Descriptions

Eyes present. Dorsal chaetae begin in segment 6 (1-2 hair chaetae 1-2 long, simple-pointed crotchets). All ventral chaetae alike, with upper tooth about twice as long as the lower, 3 or 4-7 per bundle. Penial chaetae present. 3.6-3.8 mm. Stout worms that do not swim. (ref. ID; 1257)

Nais andina Cernosvitov, 1939 (ref. ID; 6554)

Descriptions

Pigments present, eyes present. Ventral chaetae 3 or 4 (5) per bundle, all about the same length, 104-112 µm anteriorly, 90-107 µm posteriorly, upper teeth longer and thinner than the lower, becoming equally long posteriorly, all pectinate. Needles 1 or 2 per bundle, 62-95 µm, bluntly simple-pointed, nodulus distal, hair chaetae 0-2, frequently absent, up to 184 µm. Penial chaetae 2 or 3 on each side of VI, straight with distal knob. Spermathecal ducts long, other reproductive structures not clearly distinguishable. (ref. ID; 6554)

Remarks

The needles in this species are only up to 80 µm long according to Cernosvitov (1939) and the hairs are short and frequently absent, especially anteriorly and somtimes entirely. The pectinate ventrals were described by Martinez-Ansemil and Giani (1986), who named a new form (pectinata) for ther material. In their material the needles measured 90-120 µm, the hairs 100-250 µm, the ventrals 100-120 µm, i.e., all larger than our specimens. They discounted the record from India by Naidu and Shrivastava (1980). The type series (BMNH 1949.1.4.26-50) was examined for us by Mr. E.G. Easton, who confirms that the ventral chaetae of the types are not pectinate. (ref. ID; 6554)

New record

Peru: Murilaya River, Huenque and Puna Bay, Lake Titicaca, 19-23 December 1982, coll. E. Bustamente, 3 immature and 1 mature specimens. (ref. ID; 6554)

Nais barbata O.F. Muller, 1773 (ref. ID; 1257, 1663, 1923, 3692, 5939, 7854)

Synonym

Nais obtusa (Gervais, 1838) in Southern, 1909 (ref. ID; 1257)

Descriptions

Needle setae hair-like, with fine tip. Hair and needle setae each up to 5 per bundle. Ventral setae with relatively short teeth. (ref. ID; 1663)

Ventral setae posterior to segment 5 heavier, shorter, and more curved than anterior ones. (ref. ID; 1923)

Nais behningi Michaelsen, 1923 (ref. ID; 3692, 5939, 7854) reported year? (ref. ID; 1663)

Descriptions

Needles single-pointed. Ventral setae of II to V with long thin teeth. (ref. ID; 1663)

Nais communis Piguet, 1906 (ref. ID; 1257, 1663, 1861, 1923, 3692, 6554, 6913, 7211, 7854) reported year? (ref. ID; 3446) reported author and year? (ref. ID; 5939), cf. communis Piguet, 1906 (ref. ID; 6972)

Synonym

Nais heterochaeta Benham, 1893 (ref. ID; 1257)

Descriptions

Needles bifid. Needle teeth short and divergent. Stomach widening gradually. Very common species. Cosmopolitan. (ref. ID; 1663)

N. communis frequently burrows a few centimeters into the substratum, unlike the other naidids. (ref. ID; 1861)

Distal bifurcations of dorsal needle setae short, diverging; posterior ventral setae with bifurcations of approximately the same length. Stomach dilates gradually; ventral setae of segments 2 to 5 very similar to more posterior ones. (ref. ID; 1923)

Dorsal chaetae from VI, 1 or 2 serrate hairs and 1-3 pectinate needles, 80-90 µm long, with distinct teeth. Ventral chaetae all 5-7 per bundle, the upper teeth thinner than, but about as long as, the lower, 80-100 µm, no difference between anterior and posterior bundles. (ref. ID; 6972)

Remarks

This specimen was separated from N. variabilis by W.J. Harman on the basis of the presence of eyes, the lack of an abrupt widening of the stomach, and the chaetal sizes (ventrals anterior 60-71 µm, posterior 46-56 µm, needles 33-44 µm, hairs 104-154 µm). (ref. ID; 6554)

Pectinate needles may be found in several naidid species that are usually described as possessing bifid needles. This is not the appropriate place to discuss the taxonomy of Nais species, but I should indicate that R.D. Kathman (Sidney, B.C., personal communication) and the author have seen many specimens that share some of the supposed characteristics of N. communis and Nais variabilis Piguet, 1906. Various criteria for separating them have been examined by us, none of which can be applied consistently. (ref. ID; 6972)

New records

Peru: Lake Umayo, Lake Titicaca basin, June 1985, coll. R.O. Brinkhurst, 1 specimen. (ref. ID; 6554)

Material examined

1 specimens, stream at Laoshan, north of Qingdao, Shandong Province, 17 April 1987, R.O. Brinkhurst collection. (ref. ID; 6972)

Nais elinguis O.F. Muller, 1773 (ref. ID; 1257, 1663, 1923, 3692, 6554, 6913, 7211, 7854) reported year? (ref. ID; 1928, 3446) reported author and year? (ref. ID; 5939)

Descriptions

Needles bifid. Needle teeth long and almost parallel. Ventral setae posterior to V not especially thickened. (ref. ID; 1663)

Distal bifurcations of dorsal needle setae long, approximately parallel; ventral setae with distal bifurcations twice as long as proximal. (ref. ID; 1923)

The ventral setae of segments 2-5 are slightly longer, straighter, and much slenderer than those of the following segments. The prostomium is conical, or rounded, only as long as the base is broad. (ref. ID; 1928)

Remarks

In this material, the anterior ventral chaetae measured 80-97 µm, the posterior ventral chaetae 68-75 µm, the needles 60-65 µm, and the hairs 130-150 µm. These measurements agree with previous ones in the literature. (ref. ID; 6554)

This species differs from most Nais species in possessing more than the usual single hair and needle seta, bearing three of each per bundle regularly. This is matched by N. pseudobtusa Pig. and exceeded by N. barbata Muller, which are otherwise more typical Nais species. Nais elinguis may have serrate hair setae, as do the specimens collected from the Kitimat River, British Columbia, a characteristic first noticed in other material by R. Grimm (personal communication). This adds to the list of unusual features of this species (Sperber 1948). (ref. ID; 7211).

New record

Peru: Lurin River near Cieneguilla, Depto. Lima, August 1970, coll. J. O'Neill, 2 specimens, W.J. Harman collection. (ref. ID; 6554)

Nais inflata Liang, 1963 (ref. ID; 6651, 6972) reported year? (ref. ID; 6597)

Descriptions

Body thick, rather opaque. May be covered in foreign particles. Eyes small (occasionally absent). Pharynx in II and III, stomach gradually widening in VIII. Commissural vessels simple in I-V, dorsal vessel left-ventral in position after VII. Nephridia from VII, paired, not packed around ventral vessel. Dorsal chaetae from VI, mostly 2 or 3 but up to 5 hairs and 3 or 4 (range 2-6) needles, 120-190 and 96-112 µm, respectively. Needles straight basally, nodulus slightly distal, minutely bifid with closely applied parallel teeth (?or simple-pointed). Ventral chaetae 5-8 in II, 105-116 µm long, nodulus slightly distal, teeth about equally thick but the upper longer; on the other segments 2-5 per bundle, 87-114 µm. Penial chaetae 3 per bundle, 80-130 µm long. Vascular system forming an anterior network. Spermathecae with distinct ducts. Atria ?opening into pockets. Spermathecal and male pores in chaetal line. Clitellum from in front of the spermathecal pores on V to behind the ventral chaetae of VII, apparently present between male pores. Swims with spiral movements. (ref. ID; 6972)

Remarks

Examination of new specimens has permitted confirmation of the original description plus the addition of several characters. The body wall may be covered in sand grains (probably a combination of bacteria and foreign particles embedded in muscus). The reproductive system has been examined, and the spermathecal and penial chaetae observed. Observations of the atria and male pores are based on 3 whole mounted specimens and no definitive statements can be made. The first conclusion regarding this taxon is clear: it is not a synonym of Nais communis, suggested as a possibility by Brinkhurst (Brinkhurst & Jamieson 1971). The second conclusion is that it is very similar to Specaria fraseri, described by Brinkhurst (1978). The chaetae of S. fraseri appear quite similar to those of N. inflata in size, form, and number. The needles may be slightly shorter (85-95 instead of 96-112 µm) but the tips are very obviously bifid under x250 magnification. The needles of N. inflata are so minutely bifid that oil-immersion lenses are required to see the short, closely applied teeth. To the observer the needles of N. inflata seem thinner at the tip, but camera lucida drawings do not substantiate this. There are usually 3 hairs and needles in S. fraseri, up to 6 ventrals in II, 2-4 in other bundles. In N. inflata there are usually about the same number but higher maxima are reported, and are confirmed here. It seems best to await the availability of sectioned mature specimens before synonymizing these taxa. The zoogeographic distribution is perhaps not a problem, since the west coast of North America shares some Pacific rim species with China, and the tubificid Teneridrilus mastix (Brinkhurst) has recently been found in the estuary of the Pearl River, China, following its original description from the lower Fraser River, British Columbia. However, N. inflata seems to be widespread in the Changjiang River (Liang 1987) and not restricted to the area close to the river mouth as S. fraseri may be in the Fraser River, British Columbia.
  • The generic status of these two taxa is not certain. They share the somewhat large chaetal number of Specaria josinae (Vejdovsky), the type species of the originally monotypic genus erected by Sperber (1948). The vascular system and nephridia of N. inflata differ from those of Specaria, but the value of these characters for defining genera is not firmly established. The ventral chaetae do not change in size and form between V and VI, as in almost all Nais species. The presence of eversible pockets receiving the atrial ducts is hinted at in the new material of N. inflata, but it would appear that the clitelum does exist between the male pores in this taxon, even if it is missing for an area around the potential pockets, if that is what they are. The illustration of the male reproductive system in Specaria josinae presented by Sperber (1948) and redrawn here apparently shows the clitellum developed around the openings of the pockets. Liang has observed S. josinae in central China. We have decided to leave N. inflata in the genus Nais because of doubts about the consistency of some characters at the generic level. (ref. ID; 6972)

    Material examined

    39 specimens, Fuling, Sichuan Province, 3 November 1984. Species limited to Yangtze River main trunk and some tributaries, Honan, Hubei, and Sichuan provinces, Cina. Liang Yanling collection. (ref. ID; 6972)

    Nais obtusa (Gerv.) (ref. ID; 1928)

    Descriptions

    This species is evidently very variable, as the figures of the ventral setae given by various writers differ greatly. The dorsal bundles are composed of two kinds of capillary setae, the shorter ones being curved near the middle, and about 1/3 the length of the long ones. Each bundle contain 1-2 long, and 2-4 short setae. (ref. ID; 1928)

    Nais pardalis Piguet, 1906 (ref. ID; 3692, 6554, 6972, 7854) reported year? (ref. ID; 1663) reported author and year? (ref. ID; 5939)

    Synonym

    Nais bretscheri Michaelsen, 1989: Chen, 1940 (ref. ID; 6972)

    Descriptions

    Needles bifid. Ventral setae of at least some segments behind V with some thickened setae or a single giant seta. (ref. ID; 1663)

    Eyes present. Ventral chaetae in II-V, 3 per bundle with the upper tooth much longer than the lower, 71-86 µm, nodulus median or slightly proximal. From VI ventral chaetae 2 or 3 per bundle, of 2 forms: (i) normal chaetae with teeth the same length or the upper ones slightly longer, 65-71 µm and (or) (ii) thick chaetae with the upper tooth 2-3 times as long as the lower. Dorsal chaetae 1 or 2 hairs up to 118 µm long and 1 or 2 bifid needles, 41-56 µm long, with short thin teeth of equal length. (ref. ID; 6554)

    Eyes present. Dorsal chaetae from VI, 1 hair and 1 needle per bundle, needles bifid with parallel teeth. Ventral chaetae of anterior bundles only 1 or 2 per bundle (others presumed lost), with upper teeth longer than lower. From VI on single chaetae becoming thicker with very long upper teeth, the lower may be irregular in outline. (ref. ID; 6972)

    Remarks

    As expected, there are no giant chaetae in this material, and the chaetal form and sizes seem typical. The chaetal sizes are closest to those given by Chen (1940) for Chinese specimens (as Nais bretscheri). No dimensions were given for Bolivian material by Martinez-Ansemil and Giani (1986). Marchese (1986) reported N. bretscheri from Argentina. (ref. ID; 6554)

    The status of the taxa Nais-bretscheri-pardalis-lastockini-stolci is unclear. Sokol'skaya (1958) identified N. bretscheri of Chen (1940) as N. lastockini Sokol'skaya, 1958, a species described from a lake in the floodplain of the Amur River, USSR. Chekanovskaya (1962) suggested that N. lastockini might prove to be a synonym of N. pardalis, a position adopted by Brinkhurst and Jamieson (1971). The differences involve the gradual or abrupt widening of the stomach and the position of the nodulus on the needles (almost medial versus medial). Nais pardalis may simply be a form of N. bretscheri with giant chaetae undeveloped, a feature that may be associated with maturation. Nais stolci was described by Hrabe (1981) from Czechoslovakia. This species may have be 4 or 5 ventral chaetae per bundle from X onwards, the upper teeth of which are exceedingly long, (2-4 times the length of the lower). The needle teeth appear to be longer than those of N. pardalis, too. Both N. pardalis and N. bretscheri have been reported from China. My opinion is that there has been too little recognition of intraspecific variability in the Naididae in general. (ref. ID; 6972)

    New records

    Peru: Murilaya River, 300 m from Puno Bay, Lake Titicaca, 19 December 1982, coll. E. Bustamente, 1 specimen; Tirica stream, Missiones Province, August 1986, coll. I.E. de Drgao, M. Marchese, J. Peso; Dept. Loreto, Curanja Bata River, August 1966, coll. A.L. Gardner, W.J. Harman collection, Argentina: Saladillo River basin, Santa Fe Province, October-November 1984, coll. E. Drago and U. Molet, 1 specimen at each side. (ref. ID; 6554)

    Material examined

    1 specimen, Zhujiang (Pearl) River, Huang-zhu-qi, Guangzhou, Guangdong Province, 1985. Qi Sang collection. (ref. ID; 6972)

    Nais pseudobtusa Piguet, 1906 (ref. ID; 1257, 1663, 1923, 3692, 6913) or 1909 (ref. ID; 6618) reported year? (ref. ID; 3446, 4491) reported author and year? (ref. ID; 5939)

    Descriptions

    Needle setae hair-like, with fine tip. Dorsal hair and needle setae each 1 to 3 per bundle. Ventral setae with relatively short teeth. (ref. ID; 1663)

    Ventral setae posterior to segment 5 thin, not strongly curved. (ref. ID; 1923)

    Nais simplex Piguet, 1906 (ref. ID; 1257, 1663, 1861, 1923, 3692, 6554) reported author and year? (ref. ID; 5939)

    Descriptions

    Needles single-pointed. Needle setae with a more blunt tip. Ventral setae with relatively short teeth. (ref. ID; 1663)

    N. simplex is surface-dweller. (ref. ID; 1861)

    Dorsal needles setae with short, blunt tips. (ref. ID; 1923)

    Ventral chaetae of II-V, 2-6 per bundle, longer, straighter, and thinner than the rest, with a proximal nodulus and the upper tooth nearly twice as long as the lower, 100-108 µm long. The posterior ventrals are 2-5 per bundle, stouter, with teeth about the same length, 90-100 µm. Needles are 1 or 2 per bundle, robust, simple pointed, 80-90 µm, the hairs 1 or 2 per bundle, 160-173 µm. (ref. ID; 6554)

    New record

    Peru: in the reed beds of Puno Bay near Uros Village, Lake Titicaca, January 1965, coll. G.H. Lowery, Jr., 9 specimens, W.J. Harman collection. (ref. ID; 6554)

    Nais variabilis Piguet, 1906 (ref. ID; 1257, 1663, 1923, 2780, 3692, 6554, 6913, 7211, 7854) reported year? (ref. ID; 3446, 4491) reported author and year? (ref. ID; 5939)

    Descriptions

    Needles bifid. Needle teeth short and divergent. Stomach widening abruptly. Uncommon species. (ref. ID; 1663)

    Distal bifurcations of dorsal needle setae short, diverging; posterior ventral setae with bifurcations of approximately the same length. Stomach dilates abruptly; ventral setae of segments 2 to 5 with distal tooth longer than proximal. (ref. ID; 1923)

    Remarks

    The abruptly widening stomach is one of the few reliable characters for separating this species from its congeners, especially N. communis. In this material the ventral chaetae measured 86-98 µm, the needles about 80 µm, and the hairs 150-302 µm. (ref. ID; 6554)

    Specimens of this form with very long hair setae (cf. Sperber 1948) were found in the Kitimat River, British Columbia. The hair setae are 400-560 µm long, the needles being 60-85 µm. The longest hairs reported in these forms by Sperber are nearly 700 µm long; the usual length in Nais is 200-300 µm. The ventral setae of II-VI are the same length and width as those of more posterior segments. (ref. ID; 7211)

    New record

    Peru: Puno Bay at Ojerani, Lake Titicaca, 12 December 1982. coll. E. Bustamente. 1 specimen. (ref. ID; 6554)