Additions to the Rotatoria of New Zealand
Part 2. *
[Read (by title) before the Canterbury Branch, October 1, 1947; received by Editor, October 3, 1947; issued separately, May, 1949.]
The rotifers listed in this paper have not previously been recorded in New Zealand, and with few exceptions have been taken from temporary and semi-permanent pools in the Canterbury District. The species recorded in “A Reference List of the Rotatoria of New Zealand with Ecological Notes” (Russell, 1945) and “Additions to the Rotatoria of New Zealand. Part 1” (Russell, 1947) were mostly collected from small lakes and permanent bodies of water. The change in collecting grounds is reflected in the increased number of littoral rotifers recorded in the present paper.
The distribution of the Rotatoria is generally considered universal, and one contributing factor is the minuteness of rotifer eggs, which allows them to be transported by wind and other agencies. The winter or resting eggs are highly resistant to mechanical damage and may also pass intact through the alimentary tract of birds and other animals by whom they are probably transported. Rotifers will appear in almost any body of water if the physical and chemical conditions are suitable.
Two of the known factors controlling the existence of the Rotatoria are the temperature and hydrogen-ion concentration of the water, and most rotifers have a well-defined temperature and pH tolerance. For instance, Asplanchna brightwelli has, in waters so far examined, a temperature range of 8–16° C. and a pH range of 8–10, while Asplanchna intermedia, the females of which are morphologically identical with those of A. brightwelli and differ only in the males, has a temperature range of 17–25° C. and a pH range of 8–8.5. A knowledge of the tolerances of each species is often of assistance in differentiating between two morphologically closely related species.
The rotatorian population of a lake or other permanent body of water can only be determined by taking samples at regular intervals, over a period of at least one and preferably two years. Casual samples are only of significance in relation to the temperature and pH at the time of collection. One small lake near Christchurch was reputed to contain four species of the Rotatoria, but collections over a period of twelve months resulted in more than forty species being found.
In all the lakes so far examined there exists what might be called permanent species, consisting mostly of open-water rotifers which appear year after year at certain values of temperature and pH. In addition, there is also a transient population composed largely of littoral rotifers which appear for one or two years and then disappear, being replaced by other species. In the case of small temporary pools, the physical conditions change so rapidly that collections made a few days apart will often result in entirely different speecies being obtained.
[Footnote] * For Part 1, see Trans. R.S.N.Z., vol. 76, 1947, pp. 403–8,
The Reference List.
To save space, synonymies have been reduced to a minimum, and short titles have been given in the reference to original descriptions of species; as most of the latter are unavailable to New Zealand workers, additional references have been given to copies of the descriptions contained in publications available at the University College and Museum libraries of this country.
I have to thank Professor L. R. Richardson, of Victoria University College, Wellington, for many helpful suggestions when preparing this paper. I have also to thank Dr. W. H. Sheffield, of Christchurch, for supplying me with material from Lake Taylor.
Genus Taphrocampa Gosse
Taphrocampa selenura Gosse, 1887. Jour. Royal Micr. Soc., p. 1, pl. 1, fig. 1.
Locality. Semi-permanent pools near Waimakariri River, Canterbury. Rare. Found at temp. 10° C., pH 8. Av. length 170μ.
Genus Cephalodella Bory de St. Vincent
Cephalodella exigua (Gosse).
Diaschiza exigua, Gosse, 1886. Hudson and Gosse, Rotifera, vol. 2, p. 78, pl. 22, fig. 18. Harring and Myers, 1924, p. 481.
Locality. Fish ponds, Wilson's plant nursery, Christchurch. Not common. Temp. 9° C., pH 8. Length body 110μ, width 50μ, toes 30μ.
Cephalodella auriculata (Muller).
Vorticella auriculata Muller, 1773. Verm. Terr, Fluv., vol. 1, pt. 1, p. 111. Harring and Myers, 1924, p. 479.
Locality. Temporary pools near Ashley River, Canterbury. Abundant. Temp. 19° C., pH 8. Length body 87μ, toes 15μ.
Note. In “A Reference List of the Rotatoria of New Zealand” (Russell, 1945, p. 105), Diaschiza = Cephalodella taurocephalus Hilgendorf, was shown on the authority of Harring (Synopsis of the Rotatoria, 1913, p. 33) as a doubtful synonym for Diaschiza auriculata. This is incorrect, as an examination of the two descriptions shows. In addition, Hilgendorf (1902, p. 270) states that D. taurocephalus is probably synonym for D. tenuior Gosse.
Cephalodella catellina (Muller).
Cercaria catellina Muller, 1786. Anim. Infus., p. 130, pl. 20, figs. 12 and 13. Harring and Myers, 1924, pp. 465–7.
Locality. Flax swamp near Brookside, Canterbury. Not common. Temp. 20° C., pH 8. Length body 144μ, toes 25μ.
Cephalodella gracilis (Ehrenberg).
Furcularia gracilis Ehrenberg, 1831. Abh. Akad. Wiss., Berlin, 1832, p. 130. Harring and Myers. 1924, pp. 473–4.
Locality. Temporary pools near Waimakariri River, Canterbury. Not common. Temp. 9–12° C., pH 7 5–8. Length body 100μ, toes 30μ.
Genus Proales Gosse
Proales gigantea (Glascott).
Notommata gigantea Glascott, 1893. Proc. Royal Dublin Soc., new ser., vol. 8, p. 80, pl. 7; fig. 1. Harring and Myers, 1924, pp. 424–5.
Locality. Victoria Lake, Christchurch Rare. Temp. 16° C., pH 8 5. Length body 142μ, max. width 54μ, toes 12μ.
Genus Encentrum Ehrenberg
Taphrocampa saundersiae Hudson, 1885. Jour. Royal Micr. Soc., p. 614, pl. 12, fig. 9. Harring and Myers, 1929, pp. 778–9.
Locality. Temporary pools near Waimakariri River, Canterbury. Rare. Temp. 10° C., pH 8. Overall length 150μ.
Genus Gastropus Imhof
Gastropus hyptopus (Ehrenberg).
Notommata hyptopus Imhof, 1838. Infusionsth., p. 426, pl. 50, fig. 6.
Notops hyptopus Hudson and Gosse, 1886. Rotifera, vol. 2, p. 13, pl. 15, fig. 2.
Locality. Flax swamp near Brookside, Canterbury. Rare. Temp. 20° C., pH 8 Overall length 190μ, max. width 140μ.
Genus Brachionus Pallas
Brachionus bidentata Anderson, 1889. Jour. Asiatic Soc. Bengal, vol. 58, pt. 2, p. 357. Ahlstrom, 1940, pp. 167–8.
Locality. Temporary pools near Waimakariri River, Canterbury. Rare. Temp. 10° C., pH 8. Overall length 200μ, lateral anterior spines one-fifth longer than medians, intermediates almost obsolete. Mental ridge elevated and undulating. Basal plate well developed, posterior spines wanting. In addition to morphological differences between this species and cyclomorphic forms of B. quadridentatus the latter has so far not been found in waters below 18° C. in temperature. The specimens were therefore considered to be variations of B. bidentata.
Genus Keratella Bory de St. Vincent
Keratella valga var. procurva (Thorpe).
Anuraea procurva Thorpe, 1891. Jour. Royal Micr. Soc., pp. 301–6. Ahlstrom, 1943, pp. 452–3.
Locality. Pools near Waimakariri River, Canterbury. Abundant. Temp. 6.5°C., pH 8. Overall length 200μ, width 90μ, Spines: AM 37μ, AI 20μ, AL 25μ. Posterior spines: left 0–20μ, right 40–50μ. The majority of the specimens had the left spine obsolete or weakly developed. The dorsum pattern was distinct and normal for the species.
Genus Colurella Bory de St. Vincent.
Colurella bicuspidata (Ehrenberg).
Colurus biouspidatus Ehrenberg (for 1831), 1832, Abh. Akad. Wiss., Berlin, p. 129. Hudson and Gosse, Rotifera, 1886, vol. 2, p. 102.
Locality. Victoria Lake, Christchurch. Common. Temp. approx. 22° C., pH 9. Length of body 80μ, toes 15μ.
Genus Diurella Bory de St. Vincent
Diurella brachyura (Gosse).
Monocerca brachyura Gosse, 1851, Ann. Mag. Nat. Hist., ser. 2, vol. 8, p. 199.
Coelopus brachyurus Hudson and Gosse, 1886. The Rotifera, vol. 2, p. 69, pl. 20, fig. 21.
Locality. Fish pools, Wilson's plant nursery, Christchurch. Temp. 6° C., pH 8. Length of body 122μ, toes 35μ. Rare.
Genus Asplanchna Gosse
Asplanchna priodonta Gosse, 1850. Ann. Mag. Nat. Hist., ser. 2, vol. 6, p. 18. Hudson and Gosse, Rotifera, 1886, vol. 1, p. 123.
Locality. Lake Taylor, Canterbury. Common. Est. temp, and pH, 18° C. and 8. Length 500μ, max. width 200μ.
Ahlstrom, E. H., 1940. A Revision of the Rotatorian Genera Brachionus and Platyias. Bull. Amer. Mus. Nat. Hist., vol. 77, art. 3, pp. 143–184.
—— 1943. A Revision of the Rotatorian Genus Keratella. Bull. Amer. Mus. Nat. Hist., vol. 80, art. 12, pp. 411–457.
Harring, H. K., and Myers, F. J., 1924. Rotifer Fauna of Wisconsin, Pt. 2. Trans. Wis. Soc. Sc. Arts Lett., vol. 20, pp. 553–562.
—— 1929. Rotifer Fauna of Wisconsin, Pt. 4. Trans. Wis. Soc. Sc. Arts, Lett., vol. 23, pp. 667–808.
Hilgendorf, F. W., 1902. The Rotifera of New Zealand. Trans. N.Z. Inst., vol. 35, pp. 267–71.
Russell, C. R., 1945. A Reference List of the Rotafera of New Zealand with Ecological Notes. Trans. Royal Soc. N.Z., vol. 75, Pt. 2, pp. 102–123.
—— 1947. Additions to the Rotatoria of New Zealand, Part 1. Trans. Royal Soc. N.Z., vol. 76, Pt. 3, pp. 403–8.