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Bacillariophyta) from South-Central China

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Bacillariophyta) from South-Central China Phycological Research 2016; 64: 274–280 doi: 10.1111/pre.12145 ........................................................................................................................................................................................... New freshwater diatom genus, Edtheriotia gen. nov. of the Stephanodiscaceae (Bacillariophyta) from south-central China John P. Kociolek,1,2,3* Qingmiin You,1,4 Joshua G. Stepanek,1,2 Rex L. Lowe3,5 and Quanxi Wang4 1Museum of Natural History and 2Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 3University of Michigan Biological Station, Pellston, Michigan, 5Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio, USA and 4College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China ........................................................................................ the flora of Europe and North America (see lists of genera fl SUMMARY reported in the freshwater diatom ora of China, Chin 1951; Qi 1995). Early attempts to describe new genera of freshwater We describe a new genus and species of the diatom family diatoms from China have proven difficult to verify (Porosularia Stephanodiscaceae with light and scanning electron micros- of Skvortzow 1976) or to be teratologies of previously-known copy from Libo Small Hole, Libo County, Guizhou Province, genera (Amphiraphia Chen & Zhu 1983, representing initial China. Edtheriotia guizhoiana gen. & sp. nov. has striae across valves of Caloneis; see Mann 1989). More recently, descrip- the valve face of varying lengths, and are composed of fine striae towards the margin and onto the mantle. Many round to tions of endemic species from freshwater environments of stellate siliceous nodules cover the exterior of the valve. Exter- China have grown dramatically (e.g. Li et al. 2009; Liu et al. nal fultoportulae opening are short tubes; the opening of the 1990, 2007, 2015; You et al. 2013, 2015; Peng et al. 2014; rimportula lacks a tube. Internally a hyaline rim is positioned ; among many others), and genera that are found only in the near the margin. Marginal fultoportulae possess two arcuate region (e.g. Oricymba Zhang et al. 2015) or as disjuncts with opercles. Areolae have domed cribra on the valve face. Those other regions (Gomphosinica Kociolek et al. 2015) have also near the margin do not open to the interior. One to three ses- been detailed. From freshwaters, two new genera have been sile to slightly-raised rimportulae are placed on the valve face described as endemic to China, the naviculoid genus Sichua- towards the margin; they do not terminate shortened striae nia Li et al., described from karst regions of Sichuan Province towards the center of the valve. This suite of features distin- and Tibetiella Li et al. (2010), a member of the Fragilariaceae guishes this group from other known genera in the Stephano- dicaeae. Cyclotella shanxiensis is transferred to Edtheriotia, described from mountainous regions of Tibet. making the new combination E. shanxiensis (Xie & Qi) Kocio- The purpose of the present report is to describe a new lek et al. comb. nov. It differs from E. guizhoiana by the pres- genus of the Stephanodiscaceae collected in natural areas ence of open pores near the margin of the valve. Features of south of Guiyang, in south-central China. We present light the new genus are compared and contrasted with others in microscope (LM) and scanning electron microscope (SEM) the Family Stephanodiscaceae. The two species of the genus, observations of the new genus, and compare it with similar unlike most in the family, are known only from rivers and genera. We discuss the ecological setting in which the genus is ponds from China and Japan. found, and its placement among similar genera of the family. Key words: Bacillariophyta, China, diatom, new species, Ste- phanodiscaeae, Edtheriotia. ........................................................................................ MATERIALS AND METHODS A composite sample of benthic algae and sediments was collected in a pond at the roadside in the Libo Small Hole, Gui- INTRODUCTION zhou Province, China on 2 October 2015. Geographic coordi- nates of collection site are: N2527048000 E10769019200.The 2 China is a large (nearly 10 million km ) country of diverse water in the pond contained an abundance of Spirogyra spp. ecosystems, from northern temperate and wet in the north floating on the surface of water as well as bottom sediments east, to mountainous and dry in the northwest, to subtropical and several species of emergent higher plants. Water tempera- in the south-central portion of the country to tropical on the ture (18.5C) and pH (7.5) were measured in situ with a YSI island of Hainan (Editorial Committee for China’s Physical Pro Plus (YSI Instrument, Yellow Springs, OH, USA). Geography 1985). Elevation extends from sea level in the east ......................................................................................... fl to peaks over 8800 m in Tibet. Re ecting this diversity of * fl To whom correspondence should be addressed. habitats, the ora and fauna of China are known to have many Email: [email protected] endemic families, genera and species (e.g. Wu 1980; Chen & Communicating editor: Regine Jahn Bi 2007; Hong & Blackmore 2015), with several areas being ......................................................................................... recognized as being biodiversity hotspots, with high numbers [Correction added on 5 October 2016, after first online of unique and threatened species (Tang et al. 2006). publication: The genus name ‘Theriotia’ has been corrected to In contrast, reports on genera and species of freshwater ‘Edtheriotia’ in the title and throughout the article.]. diatoms in China suggest this group of organisms is similar to Received 9 April 2016; accepted 16 June 2016. © 2016 Japanese Society of Phycology New genus of Stephanodiscaceae 275 In the laboratory, samples were treated with concentrated Description. Valves circular, with valve face flat. A narrow nitric acid using the Microwave Accelerated Reaction System unornamented area is located near the valve margin internally. (Model MARS, CEM Corporation, Mathews, NC, USA), follow- Valve face externally has rows of siliceous granules aligned ing the procedures of Parr et al. (2004) and modified as with the striae. Near the margins externally there are fine por- described in You et al. (2015b). oids, and star-shaped to rounded granules. Areolae locular, For LM observations, cleaned materials were air dried onto open externally with round foramina, they are occluded inter- glass coverslips and permanently mounted onto slides with nally by individual domed cribra on the valve face. Individual Naphrax mounting medium (Brunell Microscopes, Chippen- areolae around the valve margin are without occlusions. Exter- ham, UK). LM observations were conducted using an Olympus nally areolae arranged in radial rows of unequal length, sepa- BX-51 light microscope (Olympus America Inc., Center Valley, rated by hyaline, non-thickened strips. These hyaline areas PA, USA) and an Olympus DP-71 digital camera. are wider in the center of the valve, narrower at the margin For SEM observations, cleaned materials were air dried and onto the mantle. Marginal fultoportulae distinct, inter- onto glass coverslips and mounted on aluminum stubs. Stubs nally each with two arcuate opercles, located on a costa were coated with approximately 1 nm of gold using a Cres- (which may be bifurcated) or between two costae. External sington 108 sputter coater (Cressington Scientific Instruments fultoportula openings are distinct, as a thickened short tube, Ltd., Watford, UK). SEM images were taken using a JSM with 1–3, sessile to slightly raised rimportulae are present on 7401 field emission SEM (JEOL, Tokyo, Japan) at an acceler- the valve face, not located at the end of a shortened stria. ation voltage of 3 kV. External fultoportula opening wider than areolae, but external We examined type material of Perithyra denaria Ehrenberg, tube is wanting. the type species of a genus suggested by Xie and Qi (1984) to possibly be related to the Chinese taxa. We examined mica Type species of the genus. Edtheriotia guizhoiana Kocio- slides from the Ehrenberg Collection at the Museum für Nat- lek et al. urkunde, Berlin, from the type locality of this taxon identified by Ehrenberg (1854). Observations were made on the micas with a Olympus BX-51 light microscope. The mica used for Etymology. Named in honor of Dr. Edward C. Theriot, Director observations is illustrated in Figure 1. of the Texas Natural Science Center and Professor, Depart- Terminology to describe valve ultrastructure follows that of ment of Integrative Biology, University of Texas, Austin, for Theriot and Serieyssol (1994) and Khursevich and Kocio- his many and varied contributions in diatom taxonomy, sys- lek (2012). tematics and evolution. Comments. Marginal fultoportulae were demonstrated in RESULTS ‘Cyclotella shanxiensis’ by Tanaka 2007. Plate 35. Figure 6; Houk et al. 2010. Tab. 295 Figure 6 or between Order Stephanodiscales Nikolaev & Harwood two costae (see Xie & Qi 1984, plate 2, fig. 8a,b; Tanaka 2007. plate 35, fig. 2; Houk et al. 2010, tab. 295, fig. 4). Family Stephanodiscaeae Glezer & Makarova Variation in the number and structure of the rimoportulae Edtheriotia Kociolek, You, Stepanek, R.L. Lowe et Q-X. Wang, was documented by Xie and Qi (1984), Tanaka (2007) and gen. nov. Houk et
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