Dictyostelium recurvibasicum Y. Li et P. Liu, 2017

Liu, Pu & Li, Yu, 2017, Dictyostelids from Jilin Province, China II, Phytotaxa 323 (1), pp. 77-82 : 78

Dictyostelium recurvibasicum Y. Li et P. Liu , sp. nov.

MycoBank 821188

When cultured at 23 C on non-nutrient agar with E. coli , sorocarps ( Fig 1A–B ) white, typically clustered, erect or semi-erect, usually branched, and sometimes with secondary branches arising from existed branches to give a clustered appearance. Sorophores sinuous, white, generally consisting of one or two tiers of cells, mostly 1.2–4.4 mm high, 7.5– 20 μm diam. Bases ( Fig 1F–H ) recurved, tips ( Fig 1E ) clavate or obtuse. Sorophores tapering from the hooks to both tips and bases. Sori white, globose, commonly 70–175 μm diam. Spores ( Fig 1D ) hyaline, oblong to oval, commonly 3.8–7.5 × 3.3–5.2 μm, with prominent polar granules. Cell aggregations ( Fig 1C ) with indefinitely radiate streams, producing one to several sorogens. Sorogens colorless. Pseudoplasmodia do not migrate.

Etymology. Referring to the recurved bases of sorophore.

Holotype. HMJAU MR062 . Isolated in 2009 from forest soil (Strain 0080–4 from mixed forest soil, 861 m elevation; Strain 0084–4 from coniferous forest soil, 766 m elevation; Strain 0085–5 from coniferous forest soil, 761 m elevation) collected in the Wangqing National Nature Reserve, Jilin Province, China in the same year.

Known distribution. China.

Commentary. Sorocarps of Dictyostelium recurvibasicum closely resemble those of another clustered dictyostelid— D. monochasioides H. Hagiw. ( Raper 1984). This species is clearly distinguishable from D. monochasioides in the following four respects. First, sorocarps of D. recurvibasicum are rarely solitary and mostly erect or semi-erect, whereas those of D. monochasioides are solitary or gregarious and erect or inclined. Second, the sorophores of D. recurvibasicum consist of one or two tiers of cells. However, the sorophores of D. monochasioides are delicate, consisting of single tier of cells except for the bases. Third, D. recurvibasicum has hook-like sorophore bases, this is the primary difference from D. monochasioides and other species of Dictyostelium . Last, the spores of D. recurvibasicum are oblong to oval. They are slightly rounder and smaller than those of D. monochasioides (spores are elliptical 2.8–3.8 × 4.4–6.4 μm to elongate ellipsoid or recurved 3.4–4.6× 7.6–9.6).

Figures

FIGURE. 1 Dictyostelium recurvibasicum and D. longosporum. D. recurvibasicum: A, B, sorocarps; C, cell aggregation; D, spores; E, sorophore tip; F, G, H, sorophore base. D. longosporum: I, sorocarps; J, cell aggregation; K, sorophore tip; L, sorophore base; M, spores; N, macrocysts. Bars: A = 5 mm; B = 3 mm; C, J = 2 mm; D–H, K–N = 10 μm; I = 10 mm.