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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Singhamoeba

Singhamoeba Sawyer, Nerad & Munson, 1992 (ref. ID; 4406 original paper)

[ref. ID; 4406]
Diagnosis; Body in locomotion of the monopodial limax type, with continuous change to the irregular multi-lobed feeding form. Normally uninulceate without disappearance of the nuclear membrane or endosome during mitosis; spindle fibers and centrioles not evident at the light microscopical level; polar caps present. Cysts round to oval with thick refractile ectocysts and a clear zone between it and the endocyst. Excystment pore at base of a protruding plug-like structure. (ref. ID; 4406)
Remarks; Singh (1952) published an extensive account of soil amoebae and established two new genera, Schizopyrenus and Didascalus to accommodate one new type that did not transform to a flagellate stage and a second type that did transform. Page (1988) made extensive studies on freshwater and soil amoebae and concluded that neither genus was sufficiently different from Vahlkampfia or Naegleria to justify them as new. He proposed the species assigned to Schizopyrenus belong to Vahlkampfia, and those assigned to Didascalus belong to Naegleria. The amoebae described as Sch. horticolus Singh & Hanumaiah, 1979, however, formed cysts that clearly are distinct from those of any known species of amoebae. Singh (1952) proposed the genus Schizopyrenus (Schizo = divide; pyrenus = kernel) for small free-living eruptive amoebae morphologically indistinguishable from those assignable to the genus Vahlkampfia. Page (1976, 1988) carried out extensive studies on free-living amoebae, and finding no valid differences between "vahlkampfiids" and "schizopyrenids", proposed that the genus Schizopyrenus be considered invalid. Amoebae belonging to the species horticolus, however, formed cysts that were unique within the family Vahlkampfiidae, being the only species within this taxon with the hood-like structure noted by Singh & Hanumaiah (1979). The new genus, Singhamoeba, is proposed to accommodate a vahlkampfiid amoebae with cyst characteristics that clearly distinguish it from any known species within the Class Heterolobosea, Order Schizopyrenida. The new combination, Si. horticola, leaves the genus Schizopyrenus without an acceptable species and it is therefore considered invalid. (ref. ID; 4406)
Type species; Singhamoeba horticola (= Sch. horticolus) [Singh & Hanumaiah, 1979], n. comb. (ref. ID; 4406)
  1. Singhamoeba horticola (= Sch. horiticolus) [Singh & Hanumaiah, 1979], n. comb. (ref. ID; 4406 original paper) reported author and year? (ref. ID; 7050)

Singhamoeba horticola (= Sch. horiticolus) [Singh & Hanumaiah, 1979], n. comb. (ref. ID; 4406 original paper) reported author and year? (ref. ID; 7050)

Descriptions

Locomotive forms monopodial, 15-26 um (average 21 um) long x 5.2-7.8 um (average 6.7 um) wide; anterior round blunt and smooth with clear hyaline zone as a distinct cap. Feeding forms constantly changing with eruptive bulges forming at nay area of the body. Posterior narrower than anterior, blunt and without a uroid. Nuclei round to oval; approximately 3.5-4.5 um in the rounded form. Mitosis promitotic with persistence of the nuclear membrane and endosome; polar caps present, intrazonal bodies absent. Cysts round to oval with distinct bulge or hood-like structure forming a plug in the excystment pore: 10-12.5 um in the rounded form, ranging up to 20 um in the oval form. Endocyst round to irregular with a clear zone between it and the ectocyst. Flagellate stages absent. Growth up to 40 degrees C. (ref. ID; 4406)
The internal transcribed spacer (ITS) sequences. (ref. ID; 7050)

Habitat

Garden soil, river mud, sewage sludge, leaf litter. (ref. ID; 4406)