Hoogenraadia (Gauthier-Lievre and Thomas, 1958)

Bobrov, Anatoly, Qin, Yangmin & Wilkinson, David M., 2015, Latitudinal Diversity Gradients in Free-living Microorganisms - Hoogenraadia a Key Genus in Testate Amoebae Biogeography, Acta Protozoologica 54 (1), pp. 1-8 : 2

Records of Hoogenraadia in China

There were two extant Hoogenraadia taxa previously recorded in China, H. cryptostoma and H. asiatica to which can be added our new record of an additional species of uncertain identity ( Shen 1983, Wang and Min 1987, Qin et al. 2011). In addition, the fossil H. asiatica was found in the sediments from late Pleistocene and Holocene ( Wang and Min 1987). The limited nature of testate amoebae records from modern China make impossible to be sure if this species still exists or if it has become extinct.

The testate species illustrated in Fig. 1 is common in the soils of Shennongjia Mountains, and it is especially abundant in the soils near the Dajiuhu peatland. The occurrence of this species was briefly noted and illustrated in Qin et al. (2011) under the name Planhoogenraadia africana – here we provide full details of this finding. The size of the specimens are as follows (N = 17): shell length 115–155 µm, shell width 50–65 µm which is mid-range in size for this genus.This was identified as Planhoogenraadia africana by Qin et al. (2011) – who also implied that the genera Planhoogenraadia and Hoogenraadia may be synonymous. However, because of the shape of the ventral apature (compare with Fig. 2c ) we do not believe this taxon to be Hoogenraadia africana but tentatively assign it to c.f. Hoogenraadia humicola .

These new records clearly illustrate the current difficulties in assigning some specimens to an unambiguous morpho-species and suggest that there is more to learn about the occurrence of this genus in China and further work is obviously required. Molecular data would obviously be very useful in sorting out the current uncertainties about the status of these morphospecies.

Figures

Fig. 1. SEM photos showing c.f. Hoogenraadia humicola found from soils in Shennongjia Mountains of central China (the left picture is from Qin et al. 2011). This was previously identified as Planhoogenraadia africana by Qin et al. (2011). Scale bars: 50 µm (a) and 20 µm (b).

Fig. 2. Shell outline and SEM photos of six species of genus Hoogenraadia Gauthier-Lièvre and Thomas 1958, with scale bar 50 μm. a – H. cryptostoma Gauthier-Lièvre and Thomas 1958; b – H. sylvatica Vucetich 1974; c – H. africana Gauthier-Lièvre and Thomas 1958; d – H. humicola Bonnet 1976; e – H. ovata Bonnet 1976; f – H. asiatica Wang and Min 1987.