Colpoda cucullus Müller, 1773

Kim, Kang-San, Ahn, Dong-Ha & Min, Gi-Sik, 2016, Record of two soil ciliates (Ciliophora: Colpodea: Colpoda) from Korea, Journal of Species Research 5 (3), pp. 463-467 : 463-465

1. Colpoda cucullus Müller, 1773

ǖǐq섬AEệ (ṳAE) ( Table 1; Fig. 1 )

Material examined. Soil with twigs under a tree, Geonhwa­gil (Sarabong Park), Jeju­do Province, Korea (33°31′ N 126°32′E), collected by Dong­Ha Ahn in November 2014 .

Diagnosis. Size 60­70 × 40­50 μm in vivo and 60­78 × 43­53 μm in impregnated specimens, broadly reniform,

colorless, rigid, swimming in a spiral path ( Fig. 1 A­E, H, I). Keel with 9­10 notches ( Fig. 1E ). Inconspicuous extrusive granules, size approximately 1 × 0.5 μm in vivo ( Fig. 1F ). Cytoplasm colorless, lipid­drops irregularly distributed. One macronucleus 11.6 × 10.8 μm on average, micronucleus 2.5 × 2.0 μm on average ( Fig. 1G ). Contractile vacuole slightly ahead of posterior end ( Fig. 1A, E ). Typical Colpoda ciliature pattern; approximately 33­35 somatic kineties, 24­27 left polykinetids, and 9­12 postoral kineties ( Table 1; Fig. 1B, H ). Silverline system cucullus ­ type ( Fig. 1J ).

Remarks. The Korean species name of Colpoda cucullus is originated from its genus name, because C. cucullus is the oldest species and type species in the Genus Colpoda .

The North American population has longer left polykinetids (17.5 μm on average vs. 12.6 μm on average) than the Korean population. Almost all the features, however, are highly similar between the two populations ( Table 1; Lynn and Malcolme, 1983).

Although, the body size and shape of Colpoda flavicans (Stokes, 1885) Foissner, 1993 is similar to C. cucullus , these two species differ in color (yellowish in C. flavicans vs. colorless in C. cucullus ) and in the position of the contractile vacuole (subterminal in C. flavicans vs. almost terminal in C. cucullus ) ( Fig. 1A, E ; Foissner, 1993).

Previously, Colpoda cucullus and C. lucida Greeff, 1888 were considered to be the same species ( Foissner, 1993). Colpoda lucida , however, can be separated from C. cucullus by the following characteristics: extrusome (distinct peripheral vs. inconspicuous); number of somatic kineties (42­47 vs. 33­35); and number of postoral kineties (13­16 vs. 9­12) ( Table 1; Kim and Min, 2015).

Habitat. Soil with twigs under a tree.

Distribution. North America, Europe, Japan, India, New Zealand, Australia, Antarctic, Korea.

Deposition. Two voucher slides with protargol­impregnated specimens are deposited in the National Institute of Biological Resources in Korea (NIBRPR0000107163, NIBRPR0000107164).

Identifiers. Kang­San Kim and Gi­Sik Min.

Figures

Fig. 1. Colpoda cucullus from live (A, D­G), protargol­impregnated(B, C, H, I) and silver nitrate­impregnated(J) specimens.A, B, D, E, H. right lateral views. C, I. left lateral views. C. arrow indicates excretory pore. E. arrow marks contractile vacuole, arrowhead indicates notches. F. extrusome at the cell margin (arrows). I. arrow marks excretory pore. J. “Cucullus­type” silverline system, arrows indicate granules. CV, contractile vacuole. lP, left oral polykinetid. Ma, macronucleus. Mi, micronucleus. rP, right oral polykinetid. Scale bars: 50μm.