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Vestnik zoologii, 35(5): 77—80, 2001
I. V. Dovgal, I. A. Grigorovich, 2001 SPIROCHONA AMERICANA SP. N. (CILIOPHORA,
CHONOTRICHIA) – A NEW NORTH AMERICAN
FRESHWATER CHONOTRICH SPECIES
FROM THE AMPHIPOD (GAMMARUS LACUSTRIS)
I. V. Dovgal1, I. A. Grigorovich2
1Schmalhausen Institute of Zoology, vul. B. Khmelnits’kogo, 15, Kiev-30, MSP, 01601 Ukraine E-mail: dovgal@dovgal.kiev.ua 2Great Lakes Institute for Environmental Research and Department of Biological Sciences, University of Windsor, Windsor, ON N9B 3P4, Canada Spirochona americana sp. n. (Ciliophora, Chonotrichia) – íîâûé âèä ïðåñíîâîäíûõ õîíîòðèõ ñ áîêî-
ïëàâà (Gammarus lacustris) èç Ñåâåðíîé Àìåðèêè. Äîâãàëü È. Â., Ãðèãîðîâè÷ È. À. – Îïèñàíà
Spirochona americana Dovgal, sp. n. ïî ìàòåðèàëàì èç îç. Ïèðàìèäà, ïðîâèíöèÿ Àëüáåðòà, Êàíà-
äà. Èíôóçîðèÿ áûëà îáíàðóæåíà íà æàáðàõ ãàììàðèäû Gammarus lacustris. Îò âîñüìè äðóãèõ âè- äîâ ðîäà Spirochona S. americana îòëè÷àåòñÿ ïðîïîðöèÿìè è ôîðìîé òåëà, ðàçìåðîì è ìîðôîëî- ãèåé ïðåäðîòîâîé âîðîíêè, ìàêñèìàëüíîé äëèíîé òåëà è ãåîãðàôè÷åñêèì ðàñïðîñòðàíåíèåì. Ê ë þ ÷ å â û å ñ ë î â à : èíôóçîðèè, õîíîòðèõè, Spirochona, Ñåâåðíàÿ Àìåðèêà. Spirochona americana sp. n. (Ciliophora, Chonotrichia) – a New North American Freshwater Cho-
notrich Species from the Amphipod Gammarus lacustris. Dovgal I. V., Grigorovich I. A. – Spirochona
americana Dovgal, sp. n. is described from specimens collected in Pyramid Lake, Alberta, Canada. The
chonotrich was found colonizing the gills of the gammarid amphipod Gammarus lacustris. S. americana differs from eight other species of the genus Spirochona in the ratio of cell length to cell width, cell body shape, size and morphology of the peristomal funnel, maximum cell size, and geographical dis- tribution. K e y w o r d s : Infusoria, chonotrichs, Spirochona, North America. The ciliate genus Spirochona Stein, 1852 comprises freshwater and marine species, which differ in the shape of cell body, size and morphology of the peristomal funnel, and structure of the adhesive organelles. Eight species of Spirochona were recognized from prior studies (Jankowski, 1973). Spirochona gemmipara Stein, 1852, a type species of the genus, colonizes the gill plates of the freshwater gammarid amphipod Gammarus lacustris. Spiro-chona gemmipara is thought to possess an extensive Palaearctic distribution, conforming to the range of its host (Jankowski, 1973, Batisse, 1994, Dovgal, 2000). However, this chonotrich is most frequently encountered in Europe (see Schodel, 1987). In Lake Baikal, valid records are provided for five species of Spirochona including S. gnathopodialis Jankowski, 1973, S. gemmipara, S. brevis Jankowski, 1973, S. globulus Swarczewsky, 1928, S. sim-plex Swarczewsky, 1928, and S. tuba Swarczewsky, 1928. The first species lives on gnathopods, whereas the other taxa colonize gill plates of gammarids. The marine species of Spirochona are represented by two taxa – S. halophila Matsudo et Mohr, 1968 and S. marina Jankowski, 1973 – both of which colonize gammarid gills (Jankowski, 1973). The former is described from the Pacific coast of North America and the latter from the The freshwater chonotrichs of the genus Spirochona were also reported from North American locali- ties (Herrich, 1884, Tibbs, 1967, cited by Jankowski, 1973); however, these distributions were not confirmed This paper formally describes a new species, Spirochona americana, from the gills of G. lacustris col- lected in Pyramid Lake, Alberta, Canada. As well, we detail taxonomic aspects of other species of Spirochona and discuss morphological features, by which these taxa differ from S. americana. Material and methods
Collection of the gammarid amphipod G. lacustris from Pyramid Lake was performed by Dr. Frank Wilhelm, New Zealand. Gammarus lacustris was collected during summer 1997 and preserved in 70% ethanol. Pyramid Lake (52°55N and 118°05W) is located in Alberta, Canada, at an elevation of 1,186 m above sea level. It has a surface area of 127.4 ha, volume of 11,130,000 m3, maximum depth of 19.0 m, and mean depth of 8.7 m. Water conductivity at the collection site was 242 μS and pH was 7.7. In the laboratory, 20 specimens of G. lacustris were examined using a dissecting microscope for the presence of commensals. On the gills of G. lacustris, we detected one chonotrich species, S. americana, coex- isting with the suctorian ciliate Dendrocometes paradoxus Stein, 1851. In order to produce permanent prepara- tions of S. americana, the gill plates with attached chonotrichs were placed in a concentrated Bouin’s fixative, then stained with Boehmer’s haematoxylin and, finally, mounted in Canada balsam. The type material Spiro-chona americana, hapantotype N 280, is deposited at the Department of Fauna and Systematics of Inverte- brates, Schmalhausen Institute of Zoology, National Academy of Sciences, Kyiv, Ukraine. Spirochona americana Dovgal, sp. n.
E t y m o l o g y . The specific name is of Latin derivation and reflects the geographi- cal distribution of this species in North America. H o s t . Adult gammarid amphipod Gammarus lacustris. Localization: edges of gill T y p e l o c a l i t y . Pyramid Lake, Alberta, Canada; sampled during summer 1997. H a p a n t o t y p e N 280: Preparation of sessile forms mounted in Canada balsam and deposited in the Schmalhausen Institute of Zoology. D i a g n o s i s . Body dimensions 47—71×24—32 μm. Cell body oviform in shape, ex- panded in middle section (fig. 1, 1, 2; tabl. 1). Maximal body width equal to or ex-ceeding width of peristomal collar slope. Macronucleus spherical and located in top third of cell body. Peristomal funnel wide, short, lacking adventitious plicae, with col-lar spiral composed of 2.5—3 convolutions. Inner, convoluted part of collar spiral al-most completely surrounded by outer convolution. Podite short and composed of adhe-sive disc. Fig. 1. Trophont of Spirochona americana from Pyramid Lake, Alberta: 1 – photomicrograph, dorsal view (×600); 2 – drawing, ventral view (scale bar 10 μm). Ðèñ. 1. Òðîôîíò Spirochona americana èç îç. Ïèðàìèäà, ïðîâèíöèÿ Àëüáåðòà, Êàíàäà: 1 – ìèêðîôîòî- ãðàôèÿ, âèä ñ äîðñàëüíîé ñòîðîíû (×600); 2 – âèä ñ âåíòðàëüíîé ñòîðîíû (ìàñøòàáíàÿ ëèíåéêà – Spirochona americana sp. n. – a New Chonotrich Species from the Amphipod … T a b l e 1 . Morphometric characterization of Spirochona americana*
Ò à á ë è ö à 1 . Ðàçìåðíûå õàðàêòåðèñòèêè Spirochona americana
N o t e . *All data based on 10 randomly selected specimens. All measurements in μm. Abbreviations: X – arithmetic mean; Min – minimum; Max – maximum; SD – standard deviation; Sx – standard error. T a b l e 2 . Comparative characteristics of species of the genus Spirochona (after A. V. Jankowski (1973) and
own data)
Ò à á ë è ö à 2 . Ñðàâíèòåëüíàÿ õàðàêòåðèñòèêà âèäîâ ðîäà Spirochona (ïî äàííûì À. Â. ßíêîâñêîãî
(1973) è ñîáñòâåííûì)
N o t e . I – body shape; II – convolutions of peristomal funnel spiral; III – ratio of peristomal funnel length to body length; IV – adventitious plicae of peristomal funnel; V – lateral sacs of peristomal funnel; VI – width of lower body section; VII – pseudostyle; VIII – body length (in μm); IX – ratio of body N a r r a t i v e . This species is probably related closely to S. gemmipara as it also pos- sesses a non-flattened, elongated body cell, a collar spiral consisting of 2.5—3 convolu-tions and a relatively short peristomal funnel which extends 1/3 the body length (tabl. 2). However the two taxa differ in the ratio of body length to body width and by the absence in S. americana of adventitious plicae and lateral sacs on the peristomal funnel. Based on the ratio of body length to body width, S. americana resembles S. globulus and S. halophila, but the former has a shorter peristomal funnel than the two other taxa (tabl. 2). Two species in the genus, i. e. S. halophila and S. marina, oc-cur exclusively in marine habitats. Spirochona americana can be discriminated from S. simplex in that its cell body is not flattened, while in the latter species it is dorso-ventrally compressed. A. V. Jankowski (1973) hypothesized that speciation in the sessile Chonotrichia may be associated with their adaptation to a specific host species and specialization to a site on the host body, as well as co-evolution with the host species. A. V. Jankow- ski (1973) further inferred that adaptive radiation of S. gemmipara in Lake Baikal has led to the assemblage of four endemic species of Spirochona. It has yet to be established what relationships exist between S. americana and S. gemmipara, but the two species exhibit similar host and cite-specific affinities. It is possible that S. americana represents a rare form of ciliates speciation, resulting from the geographic isolation of its host species’ populations on the different continents. Acknowledgements
Authors thank Frank Wilhelm and Jonathan Witt for providing the sample from, and information on Pyramid Lake. Comments from Hugh MacIsaac improved the clarity of the manuscript. Batisse A. Sous-classe des Chonotrichia Wallengren, 1895 // de Puytorac P. Traité de Zoologie. Anatomie, Systématique, Biologie. Tome II. Infusoires ciliés. Fasc. 2. Systématique. – Paris ; Milan ; Barcelone : Masson, 1994. – P. 433—473. Dovgal I. V. The distribution and variability of chonotrichs (Ciliophora, Chonotrichia) of the Ukrainian fauna. Communication 1. Spirochona gemmipara // Vestn. zoologii. – 2000. – 34, N 4—5.– P. 87—
Jankowski A. V. Infusoria. Subclass Chonotricha. – Leningrad : Nauka, 1973. – 353 p. – (Fauna of USSR; Schodel H. Sesshafte Wimpertiere (Peritricha, Chonotricha, Suctoria) auf Asellus aquaticus und Gammariden // Limnologica. – 1987. – 18, N 1. – S. 83—166.

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