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Thaiszia - J. Bo ., Košice, 35: 104–113, 2025
h ps://doi.o g/10.33542/TJB2025-2-04
THAISZIA
JOURNAL OF BOTANY
Fissidens on anus (Bach.Pyl.) S eud. and allies: aqua ic
b yophy es o he Asi g ani e highlands (A abian Peninsula)
Vincen Hugonno & Flo ine Pépin
1 25 Impasse des Oponces, 43380 Blassac, F ance; hugonno . ince[email p o ec ed]
Hugonno V. & Pépin F. (2025): Fissidens on anus (Bach.Pyl.) S eud.
and allies: aqua ic b yophy es o he Asi g ani e highlands (A abian
Peninsula). – Thaiszia – J. Bo . 35: 104-113.
Abs ac : Two aqua ic b yophy es o No he n cha ac e , Fissidens
on anus and Lep odic yum ipa ium, a e epo ed o he i s ime
om he A abian Peninsula. A syn hesis based on new ield
obse a ions and a e iew o he li e a u e p o ides an o e iew o
he aqua ic b yo lo a o he Peninsula. The i e species o ming his
excep ional assemblage in A abia a e mapped. They a e es ic ed o
wadis (d y i e bed ha lows only a e ain) ca ed in o g ani e
bed ock ha e icien ly channel and concen a e ain all uno –
pa icula ly unde he in luence o he monsoon – in o localized zones
o pe sis en mois u e. The conse a ion s a us o hese species is
b ie ly discussed.
Keywo ds: aqua ic b yophy es; implu ium; Asi moun ains; Fon inalis
hypnoides; Lep odic yum ipa ium; Rhynchos egium ipa ioides.
In oduc ion
B yophy es, pa icula ly aqua ic species, a e closely dependen on wa e o hei
ep oduc ion and physiological unc ions. Unlike ascula plan s, hey lack ue oo s
and conduc ing issues, abso bing wa e di ec ly h ough hei su aces (Oli e e al.
2005). Thei sexual ep oduc ion equi es he p esence o wa e on plan su ace,
allowing lagella ed spe ms o swim o he a chegonia (Glime 2007). Amphibious and
aqua ic b yophy es di e in hei le el o specializa ion o aqua ic imme sion.
Amphibious species inhabi hyd ologically uns able en i onmen s, such as ocky
a eas o i e banks subjec o egula looding, and exhibi a ole ance o empo a y
105
subme sion while equi ing eme ged phases o g ow h and ep oduc ion (Die ßen
2001; S eam B yophy e G oup 1999). In con as , aqua ic species a e es ic ed o
pe manen ly o nea -pe manen ly subme ged habi a s, such as i e s and ponds,
and de elop speci ic mo phological and ana omical ai s, such as hin lea es,
educed suppo ing s uc u es, and he absence o a cu icle, o op imize gas
exchange in sa u a ed en i onmen s (Glime 2007). This ecological g adien , anging
om amphibious o s ic ly aqua ic species, e lec s a p og essi e adap a ion o
hyd ic condi ions, wi h specializa ion closely linked o he du a ion and equency o
imme sion (Glime & Vi 1984; Rimac e al. 2022).
In he A abian Peninsula, whe e a hype -a id clima e p e ails and pe ennial i e s
a e i ually absen (Glennie 1987; Vincen 2008), su ace wa e occu s only
in e mi en ly in wadis, epheme al s eambeds ha low b ie ly a e in ense ain all
e en s. Unde such condi ions, he occu ence o aqua ic b yophy es is highly
unexpec ed. The disco e y o Fon inalis hypnoides Ha m. a Jabal Ib ahim, Saudi
A abia – a uly aqua ic species ypically con ined o s able i e sys ems – was
he e o e ema kable (Kü schne 1989). This a icle epo s some new popula ions
o se e al s ic ly aqua ic species, among which Fissidens on anus (Bach. Pyl.) S eud.
and Lep odic yum ipa ium (Hedw.) Wa ns .. I includes an upda ed e iew o he
li e a u e on aqua ic b yophy es o he A abian Peninsula, inco po a ing ecen
con ibu ions.
Ma e ial and Me hods
Aqua ic species we e selec ed based on he BET (B yophy es o Eu ope T ai s) ai
da abase (Van Zuijlen e al. 2023), wi h amphibious axa, which a e mo e nume ous
han aqua ic ones in he A abian Peninsula, excluded om he analysis. In cases o
ambigui y, we elied on he habi a obse ed in he ield in Saudi A abia, and only
species ha we e ully and pe sis en ly subme ged we e conside ed (C a oneu on
ilicinum (Hedw.) Sp uce, Vesicula ia mon agnei (Bél.) B o h. we e no u he
conside ed). Species no men ioned in Van Zuijlen e al. (2023) we e sys ema ically
e iewed o assess hei ecological a ini ies, d awing p ima ily on li e a u e such as
Kü schne ’s egional s udies.
Field su eys we e ca ied ou be ween Janua y and Ma ch 2024 & 2025 in he Asi
Moun ains o Saudi A abia, o documen no ewo hy o p e iously un eco ded
b yophy e axa in he A abian Peninsula – a egion whe e he b yo lo a emains
ela i ely unde explo ed. Si e selec ion was guided by geological and opog aphical
maps, and p io i ized a eas wi h po en ial mois u e sou ces such as wadis, sp ings,
and we lands. Accessibili y was also conside ed, a ou ing loca ions eachable wi hin
a 5 km walk ia exis ing ails.
Fo Fissidens on anus, ep oduc i e s uc u es (game angia and spo ophy es)
we e sys ema ically sea ched o bo h in he ield and in he labo a o y, using
specimens collec ed du ing he su eys. To acili a e he obse a ion o e ile buds,
lea es ha e been emo ed wi h o ceps. These specimens a e now p ese ed in he
au ho s’ b yological he ba ium.
106
S udy si es
All known popula ions o aqua ic b yophy es in Saudi A abia a e con ined o he
Asi Moun ains, one o he highes and mos biologically di e se egions o he
A abian Peninsula, along wi h he Yemeni Highlands. The Asi ange, composed
p edominan ly o P ecamb ian g ani e and g anodio i e, o ms pa o he A abian
Shield. These moun ains ise sha ply o ele a ions be ween 2,400 and 2,600 me e s
abo e sea le el, c ea ing a d ama ic esca pmen along he Red Sea o he wes , while
g adually descending eas wa d owa d he A abian Pla o m (Sayed & Mas ahi
2023).
The egion’s geology, ma ked by i s ex ensi e g ani ic bed ock, in luences bo h
hyd ology and soil de elopmen , c ea ing habi a s ha suppo specialized
b yophy e communi ies. The clima e o Asi is classi ied as semi-humid and mon ane,
wi h a e age annual empe a u es anging om 16 o 18 °C. I is cha ac e ized by a
bimodal ain all pa e n, wi h p ima y p ecipi a ion peaks occu ing in win e and
sp ing, and a seconda y peak du ing he summe mon hs (July–Augus ) due o he
in luence o he sou hwes e n monsoon. Annual ain all a ies conside ably wi h
ele a ion and exposu e bu a e ages a ound 500 mm ( o mo e de ails see Vincen
2008). This ela i ely high and seasonally dis ibu ed p ecipi a ion suppo s a mo e
mesic ege a ion co e compa ed o he su ounding a id lowlands.
Resul s
Fi e s ic ly aqua ic b yophy e species a e now known o occu in he A abian
Peninsula (Tab. 1). Fissidens on anus, Lep odic yum ipa ium, Rhynchos egium
ipa ioides and Fon inalis hypnoides ha e been obse ed on se e al occasions in
Saudi A abia. The new locali ies a e lis ed in he ollowing:
Fissidens on anus (Bach.Pyl.) S eud.: SAUDI-ARABIA, 2025/03/13, 2,6 km SSE Ash
Sha a, 1980 m, 21°3'5"N, 40°19'43"E; 2025/03/13, 4 km S Ash Sha a, 1810 m,
21°1'59"N, 40°19'8"E; 2025/03/13, 4,5 km SSW Ash Sha a, 1650 m, 21°2'6"N,
40°18'15"E; 2024/03/02, 1,6 km S Jabal Ib ahim, 2150 m, 20°24'22"N, 41°8'16"E.
Fon inalis hypnoides Ha m.: SAUDI-ARABIA, 2024/03/23, 7 km N Tanomah, Jabal
Ib ahim, 2300 m, 18°59'42"N, 42°11'7"E.
Lep odic yum ipa ium (Hedw.) Wa ns .: SAUDI-ARABIA, 2024/03/10, 1,5 km SW
Jidanah Wadi Sho a, 2200 m, 19°46'27"N, 41°43'1"E; 2024/03/14, 3,1 km NE
Alhumaid, 1910 m, 19°52'2"N, 41°41'58"E; 2024/03/19, Alsha a Pa k, 4,5 km NW
Tanomah, 2460 m, 18°57'8"N, 42°8'32"E; 2024/03/02, 1,6 km S Jabal Ib ahim, 2150
m, 20°24'22"N, 41°8'16"E; 2024/03/23, 7 km N Tanomah, 2300 m, 18°59'42"N,
42°11'7"E.
Rhynchos egium ipa ioides (Hedw.) Ca do : SAUDI-ARABIA, 2024/03/16, 2,7 km E
Bani Sa , 2030 m, 20°6'12"N, 41°28'29"E; 2024/03/20, 5,6 km N Tanomah, 2610 m,
18°58'42"N, 42°11'22"E; 2025/03/13, 4 km S Ash Sha a, 1810 m, 21°1'59"N,
40°19'8"E; 2024/03/19, Alsha a Pa k, 4,5 km NW Tanomah, 2460 m, 18°57'8"N,
42°8'32"E.
107
The a e age ele a ion o he obse ed popula ions is 2,138 me e s. All hese
species ha e a No he n biogeog aphical cha ac e , being mos ly empe a e species
(Van Zuijlen e al. 2023).
Oxy hynchium speciosum (B id.) Wa ns . (incl. a . angus i olium P.S ø me ) has
no been obse ed bu was men ioned p e iously in Saudi A abia (Kü schne 1989)
and in Yemen (Kü schne e al. 2015).
F om an ecological poin o iew, all obse ed popula ions a e loca ed in wadis (Fig.
1, 2) ha collec uno wa e om ex ensi e smoo h g ani e slabs (Fig. 3).
The known dis ibu ion o he i e aqua ic b yophy e species is p o ided (Fig. 4).
O e all, he popula ions o aqua ic b yophy es a e all loca ed be ween 16,5°N in
Yemeni Highlands and 20,5°N in Saudi A abian Asi . Fon inalis hypnoides has he
mos es ic ed dis ibu ion, being known om only a single popula ion, eco ded a
Jabal Ib ahim o a ound o y yea s (Kü schne 1989). Oxy hynchium speciosum
and Rhynchos egium ipa ioides ha e he wides dis ibu ions wi hin he Asi
Moun ains, ex ending in o he highlands o Yemen. Fissidens on anus and
Lep odic yum ipa ium appea o be mo e con ined o he cen al ele a ions o Saudi
A abian Asi .
No spo ophy es o Fissidens on anus could be ound in Saudi A abia popula ions.
Howe e , male and emale b anches we e p esen and abundan in all he
popula ions s udied (Fig. 5).
Discusion
Fissidens on anus has a b oad global dis ibu ion, occu ing in No h and Cen al
Ame ica, as well as in Eu ope, whe e i anges no hwa d o Scandina ia, eas wa d
o Uk aine, and includes Maca onesia (Blockeel e al. 2014). In A ica, i is eco ded
in Mo occo (Ga e ossé & We ne 1932; Mai e & We ne 1934; Jelenc 1955), Alge ia
(Jelenc 1955; Ahayoun e al. 2007), Egyp (El-Saadawi e al. 2015) and Chad (Pu sell
1987; O’Shea 2006). I is eplaced by F. bessouensis Co b. in Equa o ial wes A ica
and F. palmi olius (P. Beau .) B o h. in sou he n A ica (no e ha many ancien
A ican collec ions a e e oneously a ibu ed o Fissidens on anus). Fissidens
on anus (as well as Lep odic yum ipa ium) is newly eco ded o he en i e A abian
Peninsula (Kü schne & F ey 2020). The nea es popula ion is he single one o Is ael
(Heyn & He ns ad 2004), loca ed a 1200 km No h, and ha o sou h-eas Tu key
(Yayin aş & Allen 2009), a 2000 km No h, bo h popula ions being highly localized.
In he Medi e anean egion, he nea es popula ions a e ound in he Magh eb, I aly
(Dickson e al. 2021), Slo enia (Jakob e al. 2024) and Mon eneg o (Anđić e al. 2018).
The signi ican clus e in he sou hwes e n A abian Peninsula is he e o e clea ly
isola ed.
The A abian Peninsula is o en pe cei ed as a uni o mly a id egion, ye i displays
g ea geological and geomo phological di e si y, wi h a a ie y o habi a s, some o
which a e humid. Ne e heless, he disco e y o an aqua ic species is su p ising,
gi en he a i y o such species epo ed so a om he Peninsula. In he Asi
108
Tab. 1 Aqua ic b yophy e species in he A abian Peninsula (SA: Saudi A abia; Ye: Yemen).
SA
Ye
Fissidens on anus (Bach.Pyl.) S eud.
new
x
Fon inalis hypnoides Ha m.
x
x
Lep odic yum ipa ium (Hedw.) Wa ns .
new
x
Oxy hynchium speciosum (B id.) Wa ns .
x
x
Rhynchos egium ipa ioides (Hedw.) Ca do
x
x
Fig. 1 Aqua ic b yophy e communi y wi h Fissidens on anus and Fon inalis hypnoides in Jabal
Ib ahim (Saudi A abia) (pho og aph aken in Ma ch 2025).
Fig. 2 Colony o Fissidens on anus in a wadi
nea Tai (pho og aph aken in Ma ch 2025).
Fig. 3 P esumed uno o wa e o e smoo h
g ani e slabs in Jabal Ib ahim (Saudi A abia)
(pho og aph aken in Ma ch 2025).
109
Moun ains o he A abian Peninsula, small ca chmen a eas de eloped on g ani ic
bed ock can eed wadi sys ems ha hos aqua ic b yophy es, some imes e en in a
semi-pe manen manne . While g ani e is impe meable in i s solid o m, i is o en
hea ily ac u ed and join ed, allowing some in il a ion. Howe e , in hese
en i onmen s, su ace uno plays a pa icula ly c ucial ole. Du ing episodes o
o og aphic ain all – o en enhanced by he in luence o he Indian monsoon – wa e
apidly lows o e exposed g ani e slabs and among la ge blocks and boulde s. These
su aces, o en smoo hed and compac ed, gene a e e icien uno , especially when
soils a e hin o absen . In small basins, he opog aphy and a angemen o hese
su aces c ea e na u al implu iums – a eas whe e wa e collec s and con e ges –
leading o he o ma ion o pe manen o semi-pe manen s eams and seepages
(Fig. 3). I he ca chmen is a ou ably o ien ed ( o example, no h- acing) and
bene i s om shading by opog aphy o ege a ion, e apo a ion is educed, u he
enhancing wa e pe sis ence in he landscape. These hyd ological dynamics can
suppo mic ohabi a s ha emain mois o ex ended pe iods, allowing aqua ic
b yophy es o h i e e en in an o he wise a id en i onmen .
The phy osociological app oach appea s o limi ed ele ance o aqua ic b yophy e
communi ies in Saudi A abia. Assemblages a e o en educed o one o wo
dominan species, making i di icul o iden i y meaning ul species associa ions o
apply exis ing Eu opean syn axa. Ye , he b yological assemblages associa ed wi h
Fissidens on anus a e always ema kable, e en i gene ally spa se and
inconspicuous. Fissidens on anus, and he o he s ic ly aqua ic species, a e
occasionally also accompanied by amphibious species o high he i age conse a ion
alue (C a oneu on ilicinum, Fissidens c assipes Wilson ex B uch & Schimp.,
Hyd ogonium bolleanum (Müll. Hal.) A. Jaege , Philono is has a a (Duby) Wijk &
Ma gad.).
No spo ophy es o Fissidens on anus could be ound in Saudi A abia. Howe e ,
male and emale b anches we e p esen and abundan in all he popula ions s udied.
In I aly, Dickson e al. (2021) ound ha he small capsules a e caducous and
conside ed o be he main dispe sal uni , a he han he shed spo es. Howe e , he
occu ence and caduci y o he spo ophy es ha e ye o be con i med in Saudi A abia
especially since no old emale b anches we e loca ed ( om whe e caducuous
spo ophy es would ha e o igina ed). Ce ainly, as a gued by he same au ho s,
ege a i e p opagules, along wi h s em and lea agmen s, also con ibu e o he
species' dispe sal. The ques ion o he o igin o he A abian popula ion emains
open. Gi en he p esence o la ge, well-es ablished popula ions loca ed se e al
hund ed kilome e s apa , he species can be conside ed na i e and an in eg al pa
o he aqua ic b yophy e assemblages o he A abian Peninsula. The occu ence o
s e ile popula ions o Fissidens on anus in he Asi g ani e moun ains may be
explained by long- ange o chance dispe sal, pa icula ly h ough ege a i e
p opagules anspo ed by mig a o y wa e bi ds. This mig a ion ou e, which
connec s Eas e n Eu ope and Tu key o he A abian Peninsula and A ica, could
110
Fig. 4 A abian Peninsula dis ibu ion o 1: Fissidens on anus (Bach. Pyl.) S eud.; 2: Fon inalis
hypnoides Ha m.; 3: Lep odic yum ipa ium (Hedw.) Wa ns .; 4: Oxy hynchium speciosum (B id.)
Wa ns .; 5: Rhynchos egium ipa ioides (Hedw.) Ca do ( iangle: new da a; ci cle: bibliog aphical
da a).
111
acili a e episodic in oduc ions o aqua ic b yophy es in o isola ed habi a s such as
hose ound in he Asi egion (G een & Elmbe g 2014; Hahn e al. 2009).
All hese wadis a e en i ely na u al, o en wi hou any no able hyd ological
de elopmen s, al hough some may include wa e abs ac ion o ag icul u al use.
The species does no appea o be locally h ea ened, al hough he an h opogenic
ans o ma ion o wa e cou ses could become a conce n in he medium e m.
Fu he mo e, as wa e esou ces a e ex emely limi ed in he egion, and in ligh o
ongoing clima e change and inc easingly se e e d ough s, he e is conce n ha
g owing p essu e may be exe ed on he wa e cou ses hos ing hese aqua ic
b yophy e communi ies. De ailed su eys would be necessa y o de e mine
demog aphic ends o Fissidens on anus popula ions and o he aqua ic b yophy e
species.
Fig. 5 Male and emale b anches o Fissidens on anus (Bach.Pyl.) S eud. (no e ha he species is
monoicous; lea es ha e been emo ed om he le shoo ).
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