Bull. Natn . Sci. Mus. , Tokyo, Ser. B, 22(3) , pp. 99-103, September 22, 1996

Dictyostelids in Pakistan 11. Two Newly Found Species ofDictyostelium, D. discoideum Raper andD. rosarium Raper et Cavender
By

Hiromitsu HAGIW ARA
Department of Botany, National Science Museum,4- 1- 1 Amakubo, Tsukuba, Ibaraki 305, Japan
Abstract Two species of Dictyostelium , D. discoideum Raper and D. rosarium Raperet Cavender, were newly found in Pakistan. This is the first report of D. rosarium inAsia.

Concerning the dictyostelids of Pakistan, Hagiwara ( 1992) reported 9species and 3 complexes of species. In the present paper, two more species are
enumerated based on isolates from soils collected in northern Pakistan.
Dictyostelium discoideum Raper, J. Agr. Res. 50: 135 (1935).

(Figs. 1, 2)
When cultured at 20°C on non-nutrient agar with Eschericia coli, sorocarps
solitary, rarely branched; sorophores 0.3-3.8 mm in length, with capitate tips,
sometimes with supporting cells, with supporters if prostrate, 6.5-39.5 f1m indiam. at a level 100f.1m above the bottom, 2.5-7(-10) f1m in diam. at a level 50
f1m below the top; basal disks well-developed, 25-160(-235) flm in diam.; soripale yellow, 5o-330(-350) f1m in diam. ; spores ellipsoid, usually 1.7-2.2 times
longer than broad, smooth, mostly 5.4-8.0 X 2.9-3.9 (MD* 5.8-7.3 X 3.1-3.6)
flm.
Isolates examined: V-32, 33, 34, 37 and 40, 1200m alt., pine forests, Dadar, Mansehra, Sept.
1992; B-41, 1050m alt., pine forest, Mt. Margala, Islamabad, Oct. 1992.

Distribution: Asia; China, India, Japan, Nepal. N. America; Canada,
Mexico, U.S.A.
All the isolates examined had typical morphological features of Dictyostelium
discoideum , viz., migrating pseudoplasmodia without sorophore formation,
yellow sori, and well-developed basal disks (Fig. 2A). However, they weredifferent from American isolates including the type culture NC-4 and Japanese
ones in capitate sorophore tips (Figs. 1, 2B) and smaller basal disks.
Sorocarps are usually erect, but sometimes inclined and then their sorophorebases are supported by small cells or supporting cells (Fig. 2C) . Sorocarps are* Range of mean spore diameters of the isolates examined.

Hiromitsu HAGIWARA

100Fig. I.

Dictyostelium discoideum. Sorophore tips. Bar = 10 ,urn.

Fig. 2. Dictyostelium discoideum. A. Well-developed basal disk. X 12. B. Capitate sorophore tip. X 480. C. Sorophore base with supporting cells (arrow) . X 480.

rarely prostrate and produced supporters at the point of sorophores standing up
from the agar plates.
Dictyostelium rosarium Raper et Cavender, J. Elisha Mitchell Sci. Soc. 84: 31(1968).
(Figs. 3, 4)
When cultured at 20°C on non-nutrient agar with Eschericia coli, sorocarps
usually gregarious, sometimes sparsely and irregularly branched, often prostrate;
sorophores, 0.55-3.25(-5 .05) mm in length, extending to 6.5 mm if prostrate, with

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101

I
Fig. 3. Dictyostelium rosarium. A. Sorophore tips. B. Sorophore bases (prostrate in leftand semierect in right) . Bar = 10 ,urn.

3-11 lateral sori, with supporters if prostrate, with compound and obtuse tips, 830(-45)pm in diam. at thickest part above the bottom, 5.5-17(-21)pm in diam.
at a level 50 pm below the top; sori white, 65- 330(-350) pm in diam.; spores
globose, mostly 4.6-6.4 (MD s .o-5.9)pm in diam.; pseudoplasmodia with definite
radiate streams, 0.5-11.5(-22) mm in diam., not migrating without sorophore
formation, usually producing plural sorogens.
Isolates examined: M-45, 930m alt., pine forest, near Alja, Azad Kashimir, Sept. 1991; C-45,1940 m alt., maize field, Triku Roundu, Baltistan, Sept. , 1992; B-9, along the road, Taxila, Rawalpindi, Oct. 1992; B-60, 750 m alt., along the road, Mt. Margala, Islamabad, Oct. 1992.

Distribution: N. America; U.S.A.
This is the first report of Dictyostelium rosarium in Asia. Pakistani isolates
produce smaller sorocarps with less lateral sori in number than those of theoriginal description for Dictyostelium rosarium (Raper and Cavender, 1968), butthey presented typical characteristics, viz. , lateral sessile sori along the sorophores
and globose spores.
The isolates examined often developed large pseudoplasmodia (Fig. 4A),
sometimes exceeding 20 mm in diam. In the large pseudoplasmodia, nodular
aggregates were frequently produced in the process of inflow of myxamoebae into
primary centers (Fig. 4B). Most of the nodules yielded single sorocarps and someof them reaggregated to other nodules. Sometimes the large pseudoplasmodia

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Hiromitsu HAGIWARA

Fig. 4. Dictyostelium rosarium. A. Well-developed large pseudoplasmodium. X 12. B.
Nodules produced in the process of aggregation. X 24. C. Supporter (arrow) produced
under the prostrate sorophore. X 480. D-F. Sorophore tips. D , E, X 240. F , X 480.

yielded clustered sorocarps or branched ones, the latter not commonly becoming
dichotomously branched.
Acknowledgments

I thank Dr. H. Nagao, Chiba University, for collecting soil samples at Taxila.

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References
Hagiwara, H ., 1992. Dictyostelid cellular slime molds of Pakistan I. In T. Nakaike & S. Malik(eds.), Cryptogamic Flora of Pakistan, Vol. 1, pp. 87-98. National Science Museum, Tokyo.
Raper, K . B. & J. C. Cavender, 1968. Dictyostelium rosarium : a new cellular slime mold with beaded
sorocarps. J . Elisha Mitchell Sci. Soc. 84: 31 - 4 7.