175
Mo phology and molecula phylogeny o Monomic oca yon
ima ginalis sp. no . (Ciliopho a, Hypo icha), a new soil cilia e
species om Sou h Ko ea
Kyu-Seok Chae1, Gi-Sik Min1, Kyung-Min Pa k2
1 Depa men o Biological Sciences and Bioenginee ing, Inha Uni e si y, Incheon 22212, Republic o Ko ea
2 Depa men o Biological Resou ces Resea ch, Na ional Ins i u e o Biological Resou ces, Incheon 22689, Republic o Ko ea
Co esponding au ho s: Gi-Sik Min ([email p o ec ed]); Kyung-Min Pa k ([email p o ec ed])
Copy igh : © Kyu-Seok Chae e al.
This is an open access a icle dis ibu ed unde
e ms o he C ea i e Commons A ibu ion
License (A ibu ion 4.0 In e na ional – CC BY 4.0).
Sho Communica ion
Abs ac
The mo phology and molecula phylogeny o he new soil cilia e, Monomic oca yon
ima ginalis sp. no ., which was disco e ed in he soil o om Gwangdeok Moun ain,
Hwacheon-Gun, Sou h Ko ea, we e in es iga ed. The new species is cha ac e ized
by he ollowing mo phological ea u es: cell ellipsoidal o sligh ly o a e, wi h bo h
ends ounded; co ical g anules absen ; 17–24 ado al memb anelles; h ee on al
ci i; ou on o en al ci i, wo pos o al en al ci i; one buccal ci us; 10–13 le
and 9–13 igh ma ginal ci i; i e ans e se ci i; ou do sal kine ies and h ee do -
soma ginal kine ies; wo mac onuclea nodules and one mic onucleus in be ween
mac onuclea nodules. Phylogene ic analyses showed ha M. ima ginalis sp. no .
is placed wi hin a clade con aining M. eugleni o um eugleni o um and species be-
longing o Quad is icha in he do soma ginalian hypo ichs.
Key wo ds: Cilia e, Oxy ichidae, SSU RNA gene, e es ial, axonomy
In oduc ion
Hypo ichia S ein, 1859 is one o he mos well-known cilia e axa and has
been disco e ed in o e 1,000 species ac oss in soil, eshwa e , b ackish
wa e , and seawa e wo ldwide. Resea che s ha e disco e ed many new
Hypo ichia species, and he numbe is expec ed o exceed p e ious expec-
a ions (Be ge and Foissne 1987, 1989, 1997; Be ge 1999, 2001, 2006,
2008, 2011; Foissne e al. 2002, 2008; Foissne 2016; Kuma and Foissne
2016; Pai a 2020; Foissne and Be ge 2021; Oma e al. 2024). Oxy ichidae
Eh enbe g, 1838 is he la ges amily wi hin Hypo ichia, and i is de ined by
impo an cha ac e is ics, such as he p esence o 18 on al- en al- ans-
e se ci i clus e ed in o six ecognizable g oups, which usually a ise om
six longi udinal anlagen, di iding in o a 1:3:3:3:4:4 ci al pa e n (Be ge
1999; Shao e al. 2015).
The genus Monomic oca yon was di ided in o Oxy icha by Foissne (2016),
who ound ha Monomic oca yon has mo phological ea u es ha di e om
hose o Oxy icha, mainly by one mic onucleus be ween wo mac onuclea
Academic edi o : Pa el S oe
Recei ed:
11 Augus 2025
Accep ed:
15 Oc obe 2025
Published:
5 No embe 2025
ZooBank: h ps://zoobank.
o g/113E0D94-41AC-456E-B25B-
E4E08F165B73
Ci a ion: Chae K-S, Min G-S, Pa k K-M
(2025) Mo phology and molecula
phylogeny o Monomic oca yon
ima ginalis sp. no . (Ciliopho a,
Hypo icha), a new soil cilia e species
om Sou h Ko ea. ZooKeys 1258:
174–187. h ps://doi.o g/10.3897/
zookeys.1258.168452
ZooKeys 1258: 174–187 (2025)
DOI: 10.3897/zookeys.1258.168452
176
ZooKeys 1258: 174–187 (2025), DOI: 10.3897/zookeys.1258.168452
Kyu-Seok Chae e al.: Phylogeny o Monomic oca yon ima ginalis sp. no .
nodules. To da e, 17 species o Monomic oca yon ha e been iden i ied:
M. g anula um ( ype species), M. al edi, M. balladyna, M. c assici a um,
M. elegans, M. eugleni o um eugleni o um, M. eugleni o um imb ici a um,
M. geleii, M. halophilum, M. kahlo a um, M. longici a um, M. opis homusco-
um, M. pa ahalophilum, M. pseudo u ca um, M. pseudo usi o mis, M. sap-
obia, and M. sphagni (Foissne 2016).
The p esen s udy desc ibes a new soil cilia e disco e ed in he su ace soil
laye om Hwacheon-Gun in Sou h Ko ea. Based on obse a ions o i s mo -
phology using li ing cell and p o a gol imp egna ions and i s posi ion in he
phylogene ic ee in e ed om i s 18S DNA sequence, we classi ied he new
species wi hin he genus Monomic oca yon.
Ma e ial and me hods
Sample collec ion and ligh mic oscopy
Monomic oca yon ima ginalis sp. no . was collec ed om he opsoil
laye (0–5 cm) a Gwangdeok Moun ain, Hwacheon-Gun, Sou h Ko ea
(38°06'44.9"N, 127°25'57.4"E) in May 2023. The sampling si e is si ua ed
wi hin a o es . The o es loo was densely co e ed wi h lea li e and
p o iding a mois , o ganic- ich mic ohabi a a o able o soil cilia es. The
soil a he si e was isually iden i ied as clay- ich, wi h a dense and compac
ex u e. The soil empe a u e a he ime o sampling was app oxima ely
21.1 °C, wi h a ela i e humidi y o abou 65.8%.
The soil sample was le o ai -d y o wo weeks be o e being ehyd a -
ed wi h mine al wa e (Dongwon Saemmul, Dongwon Dea Food Co., Sou h
Ko ea) o igge he excys men o cilia es. This was pe o med using he
non- looded Pe i dish me hod as desc ibed by Foissne e al. (2002). Ob-
se a ions o li ing specimens we e conduc ed using a s e eomic oscope
(Olympus SZH10, Japan) and ligh mic oscopes (Leica DM2500 and Olym-
pus BX53) equipped wi h di e en ial in e e ence con as , a magni ica-
ions anging om 50 o 1000×. The in acilia u e was isualized h ough
p o a gol imp egna ion, wi h he p o a gol powde being syn hesized ac-
co ding o he me hod o Kim and Jung (2017) me hod, and he imp eg-
na ion p ocedu e ollowing “Me hod A” om Foissne (2014). The gene al
e minology was based on Lynn (2008), whe eas speci ic e ms ela ed o
hypo ichs ollow Be ge (1999, 2008) and Foissne (2016).
Scanning elec on mic oscopy
The scanning elec on mic oscope echnique was pe o med ollowing he p o-
ocols ou lined by Foissne (2014) and Moon e al. (2020). B ie ly, he cells we e
ixed using a mix u e o sa u a ed aqueous me cu ic chlo ide and 4% osmium
e oxide in a 1:1 a io. Subsequen ly, he cells we e washed mul iple imes wi h
dis illed wa e and moun ed on glass co e slips coa ed wi h poly-L-lysine. Sam-
ples we e p ocessed using h ough an e hanol se ies and d ied using a Quo um
E3000 d ye (Quo um Technologies, Eas Sussex, UK). Finally, he specimens
we e coa ed and examined unde a ield emission scanning elec on mic o-
scope (Hi achi S-4300, Tokyo, Japan).
177
ZooKeys 1258: 174–187 (2025), DOI: 10.3897/zookeys.1258.168452
Kyu-Seok Chae e al.: Phylogeny o Monomic oca yon ima ginalis sp. no .
DNA ex ac ion, PCR ampli ica ion, and sequencing
Monomic oca yon ima ginalis sp. no . was isola ed om he aw cul u e us-
ing a glass Pas eu pipe e unde a s e eomic oscope. The cells we e insed
a leas i e imes wi h s e ile dis illed wa e and subsequen ly ans e ed o
1.5 ml cen i uge ubes, each con aining a minimal olume o wa e . Genomic
DNA was ex ac ed ollowing he p o ocol p o ided in he RED-Ex ac -N-Amp
Tissue PCR Ki (Sigma, S . Louis, MO). Fo PCR ampli ica ion o he nea ly com-
ple e SSU RNA gene, he o wa d p ime New EukA (5’-CTG GTT GAT YCT GCC
AGT-3’) modi ied om Medlin e al. (1988) and he e e se p ime LSU e 3
(5’-GCA TAG TTC ACC ATC TTT CG-3’) om Sonnenbe g e al. (2007) we e used.
The op imized PCR condi ions we e as ollows: ini ial dena u a ion a 95 °C o
2.5 min, ollowed by 40 cycles o dena u a ion a 95 °C o 30 s, annealing a
55 °C o 30 s, and ex ension a 72 °C o 4 min; wi h a inal ex ension a 72 °C
o 5 min. PCR p oduc s we e pu i ied using he QIAquick® PCR Pu i ica ion Ki
(QIAGEN, Hilden, Ge many). Sequencing was pe o med using h ee in e nal
p ime s 18S-F810 (5’-GCC GGA ATA CAT TAG CAT GG-3’), 18S-R300 (5’-CAT
GGT AGT CCA ATA CAC TAC-3’), and 18S-F1470 (5’-TCT GTG ATG CCC TTA GAT
GTC-3’) on an ABI 3700 sequence (Applied Biosys ems, Fos e Ci y, CA, USA).
Phylogene ic analyses
The 18S DNA sequence o Monomic oca yon ima ginalis sp. no . was aligned
wi h 82 spi o ich sequences e ie ed om he NCBI da abase. Fou u os ylids,
An eholos icha pa amanca (KF806443), Bakuella sub opica (KC631826), Diaxonel-
la pseudo ub a (GU942564), and U os yla g andis (EF535731), we e selec ed as he
ou g oup species. All sequences we e aligned using BioEdi (Hall 1999). The bes -
i model GTR + I (0.7090) + G (0.4500) was selec ed unde he Akaike in o ma ion
c i e ion (AIC) using jModelTes 2.1.10 (Da iba e al. 2012). Maximum likelihood
(ML) analysis was conduc ed using iq ee e sion 2.3.6 (Nguyen e al. 2015) wi h
1,000 boo s ap eplica es. The bes e olu iona y subs i u ion models we e chosen
o each molecula ma ke indi idually based on he BIC c i e ion, using he buil -in
ModelFinde p og am (Kalyaanamoo hy e al. 2017). M Bayes 3.1.7 was used o
pe o m Bayesian in e ence (BI) analysis wi h Ma ko chain Mon e Ca lo (MCMC)
o 1,000,000 gene a ions wi h a sampling equency o e e y 100 gene a ions and
a bu n-in o 2500 ees. The ‘p se ’ command was used o implemen p io pa am-
e e s in BI analyses (p io pa ame e s based on AIC ou pu pa ame e s om jMod-
elTes ). Pai wise dis ances we e calcula ed using Mega 11 (Tamu a e al. 2021).
The phylogene ic ees we e isualized in FigT ee . 1.4.4 by Rambau (2016).
Resul s
Taxonomy
Class Spi o ichea Bü schli, 1889
Subclass Hypo ichia S ein, 1859
O de Spo ado ichida Fau é-F emie , 1961
Family Oxy ichidae Eh enbe g, 1838
Genus Monomic oca yon Foissne , 2016
178
ZooKeys 1258: 174–187 (2025), DOI: 10.3897/zookeys.1258.168452
Kyu-Seok Chae e al.: Phylogeny o Monomic oca yon ima ginalis sp. no .
Monomic oca yon ima ginalis sp. no .
h ps://zoobank.o g/29271F18-00C8-46B5-8891-8AA8C768DFDE
Figs 1A–J, 2A–L, 3A–I, Table 1
Diagnosis. Size 70–90 × 20–30 μm in i o; body ellipsoidal o sligh ly o a e.
Ado al zone occupies 40% o he body leng h and is composed o 17–24 mem-
b anelles. Two mac onuclea nodules and one mic onuclei be ween wo mac-
onuclea nodules. Co ical g anules absen . Th ee on al ci i; buccal ci us;
9–13 igh and 10–13 le ma ginal ci i; ou on o en al ci i; wo pos o al
en al ci i; i e ans e se ci i. Se en do sal kine ies; ou do sal kine ies; and
h ee do soma ginal kine ies.
Type locali y. Soil sample om Gwangdeok Moun ain, Hwacheon-Gun, Sou h
Ko ea (38°06'44.9"N, 127°25'57.4"E) ( o de ails, see Ma e ial and me hods).
Type ma e ial. P o a gol-imp egna ed slide con aining he holo ype
(Fig. 1B, C, I, J) (NIBRPR00001111990) and se e al pa a ype specimens
(NIBRPR00001111991–NIBRPR00001111993) we e deposi ed a he Na ional
Ins i u e o Biological Resou ces (NIBR), Sou h Ko ea. The holo ype specimen
was ma ked by a black ink ci cle.
E ymology. Composi e o he La in p e ix i- and La in adjec i e ma ginalis,
e e ing o h ee ma ginal do soma ginal ows.
Desc ip ion. Size 70–90 × 20–30 μm in i o, and 39–54 × 16–25 μm (a e -
age 49 × 19 μm) in p o a gol p epa a ions; leng h:wid h a io abou 2.5:1 (Table
1). Ou line sligh ly o a e o ellip ical, wi h bo h ends ounded (Figs 1A–F, I, J,
2A, B). Two globula o ellipsoidal mac onuclea nodules, an e io nodule abou
8 × 5 μm and pos e io nodule abou 9 × 5 μm in p o a gol p epa a ions; one
mic onuclei, abou 3 μm in diame e in p o a gol p epa a ions, loca ed be ween
mac onuclea nodules (Fig. 1C, G, I). Con ac ile acuole sligh ly an e io o
mid-body nea le ma gin o he cell, app oxima ely 10 μm in diame e when
ully ex ended (Fig. 1A, D, E). Cy oplasm colo less, wi h lipid globules, many
i egula c ys als and ood acuoles.
Ado al zone occupies abou 40% o body leng h and is composed o 17–24
memb anelles, wi h cilia abou 13 μm long (Fig. 1A, B, I; Table 1). Pa o al and
endo al memb ane sligh ly ben and a anged in pa allel (Fig. 1B, I). All ci i wi h
cilia 8–15 μm long in i o (Figs 1A, 2C). Eigh een on o en al- ans e se ci i:
h ee on al ci i close o he ado al zone o memb anelles (Fig. 1A, B); buccal
ci us nea he an e io end o undula ing memb anes. Th ee enla ged on al
ci i nea he dis al po ion o he ado al zone, ou on o en al ci i, buccal ci -
us nea he an e io end o undula ing memb anes, and h ee pos o al en al
ci i loca ed in he cen al body, and wo p e ans e se ci i (Fig. 1B, I; Table 1).
Fi e od-shaped ans e se ci i, abou 25 μm long a anged in a V shape, each
wi h a inged dis al end (Fig. 1B, H, I; Table 1). One le (10–13 ci i) and igh
(9–13 ci i) ma ginal ow, bo h ma ginal ows non-con luen pos e io ly (Fig.
1B, I; Table 1). Fou do sal and h ee do soma ginal kine ies wi h conspicuously
long do sal cilia 10–15 μm long. Do soma ginal kine y 5 s a s nea he an e io
end o he cell and ex ends o 2/3 o he body. Th ee caudal ci i loca ed a he
ends o do sal kine ies 1, 2, and 4 on he pos e io end o he cell (Fig. 1C, J).
Mo phogenesis. S oma ogenesis begins wi h he de elopmen o a dense
basal body ha o ms he o al p imo dium o he opis he, which appea s an e-
io o he le mos ans e se ci i (Figs 2C, 3A). A loosely a anged g oup o
179
ZooKeys 1258: 174–187 (2025), DOI: 10.3897/zookeys.1258.168452
Kyu-Seok Chae e al.: Phylogeny o Monomic oca yon ima ginalis sp. no .
Figu e 1. Monomic oca yon ima ginalis sp. no . om li e (A, D–H), a e p o a gol imp egna ion (B, C, I, J). A, Ven al
iew o a ep esen a i e indi idual; B, C. Ven al (B) and do sal (C) iew o he holo ype specimen; D, E. Ven al iews
showing he body shape and con ac ile acuole (a ow); F. Do sal iew showing he do sal b is les; G. Op ical sec ion
showing he mac onuclea nodules (a ows) and mic onuclei (a owheads); H. Ven al iew showing he od-shaped
ans e se ci i wi h inged dis al ends; I, J. Ven al (I) and do sal (J) iew o he holo ype specimen. AZM, ado al zone o
memb anelles; BC, buccal ci i; EM, endo al memb ane; FC, on al ci i; LMR, le ma ginal ow; PM, pa o al memb ane;
RMR, igh ma ginal ow; TC, ans e se ci i; 1–7, do sal b is le ows. Scale ba s: 50 μm (A–C, D, F, I).
180
ZooKeys 1258: 174–187 (2025), DOI: 10.3897/zookeys.1258.168452
Kyu-Seok Chae e al.: Phylogeny o Monomic oca yon ima ginalis sp. no .
basal bodies de elops an e io o he igh side o he o al p imo dium, o ming
he undula ing memb ane anlagen o he opis he (Fig. 2D, E).
In he opis he, he sca e ed basal bodies a he an e io end o he o al p imo -
dium de elop in o on o en al- ans e se ci al anlagen (FVT anlagen) I, II and
III o he opis he (Fig. 2D). We we e unable o de e mine whe he FVT anlagen VI
is o med om FVT anlagen VI o he p o e o om IV/2. FVT anlagen V and VI
o igina e om ci i V/4 and V/3, espec i ely (Fig. 2D). In he p o e , FVT-anlagen
II and III a e newly o med om ci i II/2 and III/2, espec i ely (Figs 2E, G, 3B,
C). FVT-anlagen IV de elops om ci us IV/3 (Fig. 2E, G). FVT anlagen V and VI
Figu e 2. Monomic oca yon ima ginalis sp. no . unde scanning elec on mic oscope (A, B) and du ing mo phogenesis
(C–L) a e p o a gol s aining. A, B. Ven al and do sal iew showing he body shape and ci al pa e n; C–H. Ven al and
do sal iews o ea ly di ide s showing he o med he o al p imo dium, ado al memb anelles (a ow), I–VI ci al anlagen
and do sal kine ies anlagen (a owheads); I, J. Ven al and do sal iew o a la e di ide showing caudal ci i (a owheads);
K, L. Ven al and do sal iew o a la e di ide showing agmen a ion o he hi d do sal kine y in each daugh e cell (a -
owheads). DKA, do sal kine ies anlagen; I–VI, on o en al- ans e se ci al anlagen 1–6; OP, o al p imo dium; RMA,
igh ma ginal anlage. Scale ba s: 20 μm (A, B); 50 μm (C–L).
181
ZooKeys 1258: 174–187 (2025), DOI: 10.3897/zookeys.1258.168452
Kyu-Seok Chae e al.: Phylogeny o Monomic oca yon ima ginalis sp. no .
o igina e om FVT anlagen V and VI o he opis he (Figs 2G, 3C). Six on o en-
al- ans e se ci al anlagen a e o med in bo h p o e and opis he (Fig. 3C).
These ci al anlagen hen b oaden, b eak apa and mig a e o hei inal posi ions
as dis inc ci i (Figs 2G, I, K, 3F, H). Ci i IV/2, VI/3 and VI/4 a e no in ol ed in he
de elopmen o FVT ci i and a e eabso bed in la e s ages o di ision (Fig. 2I, K).
The FVT anlagen I–VI o m he pa e n 1:3:3:3:3:4:4 in his o de . (Figs 2I, K, 3F, H).
Righ ma ginal anlagen de elop wi hin he igh pa en al ma ginal ow (Fig.
2G). Fo ma ion o le ma ginal anlagen by he basal body could no be ob-
se ed. We con i med ha he de elopmen o he igh ma ginal anlagen de-
elops be o e he le ma ginal anlagen.
The do sal cilia u e is o med by wo g oups o p imo dia. The do sal kine ies
anlagen de elop in akine ally wi hin pa en al kine ies 1–3 below he mid-body
(Fig. 2F). Subsequen ly, hese p imo dia p oli e a e, elonga e, and di ide o mo e
in o he p o e and opis he espec i ely (Figs 2H, 3D). In la e di ide s, he igh -
mos o he h ee idges bends a he pos e io end, gi ing ise o he o ma ion
o new do sal kine ies 3 and 4 (Figs 2J, L, 3I). Th ee caudal ci i a e gene a ed
a he pos e io end o each o he new do sal kine ies 1, 2 and 4 (Figs 2J, L, 3I).
Phylogene ic analyses. The SSU RNA gene sequence o Monomic oca yon i-
ma ginalis sp. no . (PX139273) has a leng h o 2909 bp and GC con en o 46.5%.
Figu e 3. Monomic oca yon ima ginalis sp. no . du ing mo phogenesis a e p o a gol s aining (A–I). A–D. Ven al and
do sal iews o ea ly di ide s showing he o med he o al p imo dium, I–VI ci al anlagen, and do sal kine ies anla-
gen (a owheads); F, G. Ven al and do sal iew o a la e di ide showing do soma ginal kine ies anlagen (a owheads);
H, I. Ven al and do sal iew o a la e di ide showing agmen a ion o he hi d do sal kine y in each daugh e cell (a -
owheads). I–VI, on o en al- ans e se ci al anlagen 1–6; OP, o al p imo dium. Scale ba s: 10 μm (A–I).
182
ZooKeys 1258: 174–187 (2025), DOI: 10.3897/zookeys.1258.168452
Kyu-Seok Chae e al.: Phylogeny o Monomic oca yon ima ginalis sp. no .
I di e s om ha o M. eugleni o um imb ici a um (OP339741) in se en nucleo-
ides, which co esponds o abou 0.004 pai wise dis ance (Table 2). The pai wise
dis ances and numbe o nucleo ide di e ences be ween he a ailable Monomi-
Table 1. Mo phome ic da a on Monomic oca yon ima ginalis sp. no .
Cha ac e is icaHT Mean M SD SE CV Min Max n
Body leng h 52 49.6 50.0 3.6 0.8 7.3 39 54 19
Body wid h 25 19.7 20.0 2.6 0.6 13.4 16 25 19
Body leng h:wid h, a io 2.1 2.5 2.5 0.3 0.1 11.0 2.1 3.3 19
An e io mac onuclea nodule leng h 8 8.6 8.0 0.9 0.2 10.5 7 11 19
An e io mac onuclea nodule wid h 5 5.2 5.0 0.7 0.2 13.3 4 7 19
Pos e io mac onuclea nodule leng h 8 8.7 9.0 1.1 0.2 12.6 7 12 19
Pos e io mac onuclea nodule wid h 5 5.2 5.0 0.4 0.1 8.0 5 6 19
Mac onuclea nodules, numbe 2 2 2 0 0 0 2 2 19
Mic onucleus leng h 2 2.1 2.0 0.3 0.1 15.0 2 3 19
Mic onucleus wid h 2 2.1 2.0 0.3 0.1 15.0 2 3 19
Mic onucleus, numbe 1 1 1 0 0 0 1 1 19
Ado al zone leng h 21 19.7 20.0 1.3 0.3 6.7 18 22 19
Ado al zone memb anelles, numbe 20 20.6 21.0 1.7 0.4 8.5 17 24 19
Body leng h: ado al zone leng h, a io in % 40.4 39.9 40.4 3.3 0.7 8.2 34.0 46.2 19
F on al ci i, numbe 3 3 3 0 0 0 3 3 19
Buccal ci i, numbe 1 1 1 0 0 0 1 1 19
F on o en al ci i, numbe 4 4 4 0 0 0 4 4 19
Pos o al en al ci i, numbe 3 3 3 0 0 0 3 3 19
P e ans e se en al ci i, numbe 2 2 2 0 0 0 2 2 19
T ans e se ci i, numbe 5 5 5 0 0 0 5 5 19
Righ ma ginal ci i, numbe 11 10.8 11.0 1.0 0.2 9.0 9 13 19
Le ma ginal ci i, numbe 11 11.2 11.0 1.0 0.2 9.1 10 13 19
Do sal kine ies, numbe 7 7.0 7.0 0 0 0 7.0 7.0 19
Kine ids in do sal kine y 1, numbe 16 17.1 17.0 1.5 0.3 8.6 15 20 19
Kine ids in do sal kine y 2, numbe 13 14.4 14.0 1.5 0.3 10.2 12 18 19
Kine ids in do sal kine y 3, numbe 13 10.3 11.0 1.4 0.3 13.7 7 13 19
Kine ids in do sal kine y 4, numbe 4 4.2 4.0 0.6 0.1 14.5 3 5 19
Kine ids in do sal kine y 5, numbe 12 11.2 11.0 1.5 0.3 13.8 10 15 19
Kine ids in do sal kine y 6, numbe 6 5.1 5.0 0.8 0.2 15.4 4 6 19
Kine ids in do sal kine y 7, numbe 2 2.3 2.0 0.5 0.1 20.6 2 3 19
a Da a based on andomly selec ed, p o a gol-s ained specimens. All measu emen in μm. CV, coe icien o a ia ion in %; HT, holo ype specimen; M, medium; Mean,
a i hme ic mean; Max, maximum; Min, minimum; n, numbe o specimens examined; SD, s anda d de ia ion; SE, s anda d e o o he a i hme ic mean.
Table 2. Numbe o nucleo ide di e ences ( op igh ) and pai wise dis ances (bo om le ) be ween SSU RNA gene se-
quences o Monomic oca yon ima ginalis sp. no . and closely ela ed species.
1 2 3 4 5 6 7 8 9 10 11 12
1. Monomic oca yon ima ginalis sp. no . – 3 6 7 12 20 20 25 28 33 36 37
2. Quad is icha se ige a MG603606 0.002 – 8 8 13 20 19 26 30 36 37 41
3. Oxy icha mul ilinea a OK299176 0.004 0.005 – 11 12 20 20 25 27 35 36 37
4. Monomic oca yon eugleni o um imb ici a um OP339741 0.004 0.005 0.007 – 17 22 23 27 30 36 38 42
5. Monomic oca yon eugleni o um eugleni o um MK039735 0.007 0.008 0.007 0.010 – 26 24 29 30 39 41 35
6. Oxy icha li ho e a MT364897 0.012 0.012 0.012 0.013 0.016 – 30 33 33 42 42 48
7. Monomic oca yon elegans AM41276 0.012 0.012 0.012 0.014 0.015 0.018 – 35 39 41 46 41
8. He e ou osomoida lanceola a AM412773 0.015 0.016 0.015 0.016 0.018 0.020 0.021 – 5 12 17 54
9. He e ogas os yla salina MT739409 0.017 0.018 0.016 0.018 0.018 0.020 0.024 0.003 – 17 18 56
10. Kleins yla do sici a a KC411832 0.020 0.022 0.021 0.022 0.024 0.026 0.025 0.007 0.010 – 24 62
11. He e ou osomoida sinica MN524588 0.022 0.023 0.022 0.023 0.025 0.026 0.028 0.010 0.011 0.015 – 65
12. Pseudou olep us cauda us DQ910904 0.023 0.025 0.023 0.026 0.021 0.029 0.025 0.033 0.034 0.038 0.040 –
183
ZooKeys 1258: 174–187 (2025), DOI: 10.3897/zookeys.1258.168452
Kyu-Seok Chae e al.: Phylogeny o Monomic oca yon ima ginalis sp. no .
c oca yon species ange om 0.004 o 0.012 and 7 o 20, espec i ely (Table 2). In
he phylogene ic analysis, M. ima ginalis sp. no . nes s wi hin a highly suppo ed
clade (99% ML / 1.0 BI) ha also con ains M. eugleni o um eugleni o um, and he
species M. eugleni o um eugleni o um, and M. ima ginalis sp. no ., clus e s wi h
Quad is icha se ige a wi h low suppo (64% ML/ 0.6 BI) (Fig. 4).
Discussion
Compa ison o Monomic oca yon ima ginalis sp. no . wi h congene s
Wi h he inclusion o M. ima ginalis sp. no ., he genus Monomic oca yon
now con ains 18 species. Based on he body size, nuclea appa a us, and mo -
phome ic da a, he new species should be compa ed wi h he ollowing Mo-
nomic oca yon species, namely, Monomic oca yon g anula um Foissne , 2016
( ype species), M. eugleni o um eugleni o um (Kahl, 1932) Foissne , 2016,
M. eugleni o um imb ici a um Foissne , 2016, M. c assici a um Foissne ,
2016, and M. opis homusco um (Foissne e al., 1991) Foissne , 2016 (Table 3).
Figu e 4. Maximum-likelihood (ML) phylogene ic ee based on 18S RNA gene sequences, showing he posi ion o
Monomic oca yon ima ginalis sp. no . The new sequence is shown in bold and indica ed by an a ow. The numbe s a
nodes indica e he ML boo s ap alues and Bayesian-in e ence (BI) pos e io p obabili y. The es ima ed BI ee did no
eco e nodes designa ed wi h a dash (-). The scale ba co esponds o wo subs i u ions pe 100 nucleo ide posi ions.
