The Genus Mallomonopsis in the United States

Abstract

By means of electron microscopy, phytoplankton samples from several localities in the United States were examined for the silica-scale bearing genus Mallomonopsis. Three taxa are newly reported, including one new combination, Mallomonopsis bangladeshica comb. nov. Scales of one undescribed taxon are also illustrated. The genus Mallomonopsis was erected by Matvienko (1941) to hold unicellular Chrysophyceae which are morphologically very similar to species of the uniflagellate genus Mallomonas, but differ in bearing two heterodynamic flagella. The described species and varieties are M. clavata Matv. (1941), M. elliptica Matv. (1941), M. pelophila (Lund) Fott (1954) (=Ochromallomonas pelophila Lund (1942), M. robusta Matv. (1949), M. paxillata Bradley (1966), M. peroneides Harris (1966), M. salina (Asmund and Hilliard) Kristiansen (1976), M. oviformis (Nygaard) Kristiansen (1976), M. ouradion (Harris and Bradley) Harris (1966), M. parvula Diirrschmidt (1983), M. tasmanica Croome and Tyler (1983), and M. bangladeshica (Takahashi and Hayakawa) Wujek and Timpano (this paper). Marvan (1959) described M. deltoidea from Czechoslovakia. From his description and figures, this organism is clearly a The formation of mobile colonies and lack of bristles is atypical for the genus Mallomonopsis, but typical for The scales described and illustrated (with the light microscope) are characteristic of Synura petersenii complex of forms. Marvan himself states I am putting the new species in the genus Mallomonopsis at present, but it is not impossible that the creation of colonies will be more typical so that it would be preferable to put the species in the genus Synura. * Present address: Department of Botany, University of Oklahoma, Norman, Oklahoma 73019. This content downloaded from 157.55.39.254 on Sun, 04 Sep 2016 05:05:21 UTC All use subject to http://about.jstor.org/terms 74 TRANSACTIONS OF THE KANSAS ACADEMY OF SCIENCE Although there have been an increasing number of studies on American scaled chrysophytes, only one report of continental United States freshwater phytoplankton has revealed the presence of the genus Mallomonopsis (Wee et al., 1982). This study was initiated to investigate and report those taxa of Mallomonopsis that appear in the American flora, and introduces the literature of this group to American phycologists. MATERIALS AND METHODS Samples were collected and observed as previously described (Wujek, 1969). Kansas material was collected from a pond northeast of Lawrence and the Minnesota material from the Lake Itasca region (Wujek et al., 1981).