Two new species of Mastogloia Thwaites ex W. Smith (Bacillariophyceae) from Sawa Lake, southern Iraq

Abstract

Abstract:Two new species of the genus Mastogloia are described. Mastogloia sawensis sp. nov. and M. vestigiostriata sp. nov. were encountered as epiphytes on Chara sp. which covers the sediment of Sawa Lake, an isolated saline water body in southern Iraq. Mastogloia sawensis belongs to the section Lanceolatae and is closely similar to M. lanceolata but differs in raphe curvature, areolae shape and arrangement, and the presence of rounded pores at the junction of the partecta. Mastogloia vestigiostriata resembles under light microscopy to M. lyra and M. braunii but shows differences in several features including valve mantle structures, H-shaped lateral hyaline area, siliceous flanges and partectal formation. This study gives morphological details on the ultrastructure of the new species and provides a detailed comparison with all related taxa.

Morphology of two Mastogloia species (Bacillariophyta) from Lac de Guiers (Senegal) and comparison with the type material of M. braunii

“…Mastogloia lyra has a very shallow mantle on which the valve face striae continue as uniseriate rows of small pseudoloculi (Lobban & Pennesi 2014). Mastogloia vestigiostriata has a well-developed mantle with uniseriate striae composed of large pseudoloculi (Al-Handal et al 2015). Mastogloia pisculus Cleve shows similar biseriate striae on the mantle as in the Lac de Guiers population (Pennesi et al 2012).…”

“…and M. pumila var. papuarum Cholnoky) (Hustedt 1933;Cholnoky 1963;Pennesi et al 2012;Lobban & Pennesi 2014;Al-Handal et al 2015). Two recently described Mastogloia taxa (M. abnormis Al-Handal & Pennesi and M. descrepata Pennesi & Al-Handal) show a close resemblance to M. belaensis (Al-Handal et al 2016).…”

“…The same applies for the Navarro (1988) population from Puerto Rico. Pennesi et al (2011Pennesi et al ( , 2012, Lobban & Pennesi (2014) and Al-Handal et al (2015), discussing species from 'M. sect.…”

“…The most typical feature of this genus is the presence of a partectal ring representing a chamber-like modification of the valvocopula, running along the inner side of the girdle. Detailed information regarding the general morphology of the genus Mastogloia can be found in Paddock & Kemp (1990), Round et al (1990), Pennesi et al (2011Pennesi et al ( , 2012, Lobban & Pennesi (2014) and Al-Handal et al (2015). The description of most species, however, has only been based on LM observations.…”

“…The description of most species, however, has only been based on LM observations. Morphological investigations of Mastogloia species based on SEM observations are scarce and only recently increased attention is given to the ultrastructure of the different species resulting in the description of a relatively large number of new taxa (Pennesi et al 2011(Pennesi et al , 2012(Pennesi et al , 2013Graeff et al 2013;Lee et al 2014;Lobban & Pennesi 2014;Al-Handal et al 2015Pavlov et al 2016).…”