he jou nal o
biodi e si y da a
NOTES ON GEOGRAPHIC DISTRIBUTION
917
Academic edi o : Raquel Xa ie
Recei ed: 7 Augus 2025
Accep ed: 2 Oc obe 2025
Published: 9 Oc obe 2025
Copy igh © The au ho s. 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)
Abs ac . We epo Meli a alluaudi Ledoye , 1982 om Yonaguni Island, Ryukyu Islands, Japan. These speci‑
mens ep esen he i s eco d o his species om no only Japan bu also om he Philippine Sea. He ein,
we p o ide a de ailed desc ip ion and he cy och ome c oxidase subuni I (COI) sequences o he Yonaguni
Island specimens. A key o he Japanese Meli a species is also p o ided.
Key wo ds. COI, in e idal, Okinawa, Ryukyu Islands, axonomy
Yoshimu a H, Tomikawa K (2025) New eco d o Meli a alluaudi Ledoye , 1982 (Amphipoda, Meli idae) om
Yonaguni Island, Japan. Check Lis 21 (5): 917–924. h ps://doi.o g/10.15560/21.5.917
INTRODUCTION
The genus Meli a Leach, 1814 occu s in ma ine, b ackish, and eshwa e en i onmen s wo ldwide (Tomika‑
wa e al. 2022). To da e, his genus comp ises 65 species (Choi and Kim 2024; Ho on e al. 2025). Se en een
species o Meli a ha e been epo ed om Japanese wa e s (Tomikawa e al. 2024): M. bingoensis Yama o,
1987; M. choshigawaensis Tomikawa, Hi ashima, Hi ai & Uchiyama, 2018; M. hoshinoi Yama o, 1990; M. ko eana
S ephensen, 1944; M. longidac yla Hi ayama, 1987; M. miyakoensis Tomikawa & Aoyagi, 2022 in Tomikawa e
al. (2022); M. naga ai Yama o, 1987; M. nunomu ai Tomikawa & Sasaki, 2022 in Tomikawa e al. (2022); M. oga-
sawa aensis Tomikawa & Sasaki, 2022 in Tomikawa e al. (2022); M. okinawaensis Tomikawa & Nakano, 2022 in
Tomikawa e al. (2022); M. panda Tomikawa, Yama o & A iyama, 2024; M. pilop opoda Hi ayama, 1987; M. qua-
d iden a a Yama o, 1990; M. ylo ae Bulyče a, 1955; M. se i lagella Yama o, 1988; M. shimizui (Uéno, 1940); and
M. ube cula a Naga a, 1965. Howe e , axonomic s udies o Meli a emain sca ce in mos egions o Japan.
In pa icula , eco ds om he Ryukyu Islands a e limi ed, wi h only M. okinawaensis p e iously known om
b ackish wa e s o Okinawa Island (Tomikawa e al. 2022).
Recen ly, Meli a alluaudi Ledoye , 1982 was collec ed o he i s ime om he in e idal zone o Yona‑
guni Island in he Ryukyu Islands (Figu e 1). This inding ep esen s no only he i s eco d o M. alluaudi
in Japan bu also he i s eco d o his species om he Philippine Sea. In he p esen s udy, we p o ide
a de ailed desc ip ion and illus a ions o specimens om Yonaguni Island, oge he wi h mi ochond ial
cy och ome c oxidase subuni I (COI) sequences o u u e axonomic and phylogene ic s udies. In addi ion,
we p esen a dicho omous key o acili a e he iden i ica ion o Japanese Meli a species.
METHODS
The specimens we e collec ed om unde he dead co al (indica ed by an a ow in Figu e 1C) loca ed on an
in e idal sand la exposed o low ide. While s ill ali e, some specimens we e pho og aphed using a digi al
came a (EOS M6; Canon, Tokyo, Japan) wi h a lens (LAOWA 65 mm /2.8 Mac o Pho o Lens; Venus Op ics,
Hei ei, China). A e pho og aphs we e aken, he specimens we e ixed and p ese ed in 99% e hanol. All
appendages o examined specimens we e dissec ed in 50% e hanol and moun ed in gum‑chlo al medium
on glass slides unde a s e eomic oscope (SZ61; Olympus, Tokyo, Japan). The specimens we e examined
using a ligh mic oscope (Eclipse Ni‑U; Nikon, Tokyo, Japan) and illus a ed wi h he aid o a came a lucida
(Y‑IDT D awing Tube; Nikon, Tokyo, Japan). Body leng h, which was measu ed om he os um ip o he
base o he elson along he do sal cu a u e, was eco ded o he nea es 0.1 mm. The examined specimens
a e deposi ed in he Na ional Museum o Na u e and Science, Tsukuba (NSMT).
21 (5) · h ps://doi.o g/10.15560/21.5.917
21 (5): 917–924
New eco d o Meli a alluaudi Ledoye , 1982 (Amphipoda, Meli idae)
om Yonaguni Island, Japan
Hi o Yoshimu a1, Ko Tomikawa1
1 G adua e School o Humani ies and Social Sciences, Hi oshima Uni e si y, Higashihi oshima, Hi oshima, Japan
Co esponding au ho : Hi o Yoshimu a (w assebe [email protected])
Check Lis 21 (5) · h ps://doi.o g/10.15560/21.5.917
Yoshimu a and Tomikawa · Meli a alluaudi om Japan 918
Genomic DNA was ex ac ed om muscles o pe eoni es and pleoni es, using he p o ocol desc ibed by
Tomikawa e al. (2014). The p ime se used o polyme ase chain eac ion (PCR) and cycles sequencing (CS)
was LCO1490 and HCO2198 designed by Folme e al. (1994). PCR and CS we e pe o med acco ding o he
me hods desc ibed by Yoshimu a and Tomikawa (2025). The DNA sequences a e deposi ed wi h he In e ‑
na ional Nucleo ide Sequence Da abase (INSD) h ough he DNA Da a Bank o Japan (DDBJ). DDBJ accession
numbe s a e LC887590 and LC887591.
RESULTS
Family Meli idae
Genus Meli a Leach, 1814
Meli a alluaudi Ledoye , 1982
New Japanese name:
ナンヨウメリタヨコエビ
(Nanyou‑me i a‑yokoebi)
Figu es 2–6
Meli a alluaudi Ledoye 1982: 567, ig. 215—Ren 2012: 266, ig. 116.
New eco d. JAPAN — Okinawa P e ec u e • Ryukyu Islands, Yonaguni Island, Ka abu u Beach; 24°26′26″N,
122°58′26″E; in e idal zone; 17.III.2025; H. Yoshimu a leg.; unde a dead co al (Figu e 1); 1 ♂, slide, NSMT‑C
33011, DDBJ: LC887590; 1 ♀, slide, NSMT‑C 33012, DDBJ: LC887591; 1 ♂, slide, NSMT‑C 33013; 1 ♀, slide, NSMT‑C
33014.
Desc ip ion o male, 9.1 mm (NSMT‑C 33011). Head (Figu e 2A) la e al cephalic lobe ounded; an ennal
sinus incised. Pe eoni es 1–7 (Figu e 2A) do sally smoo h. Epime al pla es 1–3 (Figu e 3A–C) wi h 1, 2, and
2 sho se ae on pos e io ma gins, espec i ely; epime al pla e 3 pos e odis al co ne p oduced, en al
ma gin wi h 3 obus se ae. Pleoni es 1–3 (Figu e 3D) do sal ma gins wi hou ee h, each wi h 4 sho se ae.
U osomi e 1 (Figu e 3D) do sal ma gin wi hou ee h, wi h 2 sho se ae. U osomi e 2 (Figu es 2B, 3D) wi h a
minu e do sal oo h and 3 obus se ae on each side.
An enna 1 (Figu e 3E, F) leng h 0.6× body leng h; leng h a io o peduncula a icles 1–3 as 1.0: 1.2: 0.4;
peduncula a icle 1 pos e odis al co ne wi h obus se a; pos e io ma gin o peduncula a icle 2 wi h 6
clus e s o slende and obus se ae; p ima y lagellum 27‑a icula e; accesso y lagellum (Figu e 3F) 5‑a ic‑
ula e, e minal a icle iny. An enna 2 (Figu e 3G) leng h 0.7× leng h o an enna 1; gland cone o peduncula
Figu e 1. Collec ing loca ions and
habi a o Meli a alluaudi Ledoye , 1982.
A. Collec ing loca ions epo ed in he
p e ious s udies (ci cle) and he p esen
s udy (s a ). B. Loca ion o he collec ion
si e in he p esen s udy, Yonaguni Island.
C. Habi a on Yonaguni Island. Map da a
om he Na u al Ea h (h ps://www.
na u alea hda a.com/).
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Yoshimu a and Tomikawa · Meli a alluaudi om Japan 919
Figu e 2. Meli a alluaudi Ledoye , 1982,
male, 9.1 mm (NSMT‑C 33011). A. Habi us,
la e al iew. B. Robus se ae on do sal
ma gin o u osomi e 2, la e al iew. C.
Dac ylus o le pe eopods 3, la e al iew.
D. Dac ylus o le pe eopods 7, la e al iew.
Scale ba s: A = 1.0 mm; B–D = 0.1 mm.
Figu e 3. Meli a alluaudi Ledoye , 1982,
male, 9.1 mm (NSMT‑C 33011). A–C. Righ
epime al pla es 1–3, la e al iews. D. Do sal
ma gins o pleoni es 1–3 and u osomi es 1,
2, do sal iew. E. Righ an enna 1, medial
iew. F. Righ accesso y lagellum, medial
iew. G. Righ an enna 2, medial iew. H.
Uppe lip, an e io iew. I. Inciso , lacinia
mobilis, accesso y se al ow, and mola
p ocess o le mandible, do sal iew. J.
Righ mandible, medial iew. K. Lowe
lip, en al iew. L. Le maxilla 1, do sal
iew. M. Righ maxilla 2, en al iew. N.
Maxilliped, do sal iew. Scale ba s: A–E, G =
0.2 mm; F, H–N = 0.1 mm.
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Yoshimu a and Tomikawa · Meli a alluaudi om Japan 920
a icle 2 eaching hal o peduncula a icle 3; peduncula a icle 3 wi h obus se ae on medial su ace and
pos e odis al co ne ; peduncula a icles 4 and 5 almos same leng h; lagellum 12‑a icula e.
Uppe lip (Figu e 3H) en al ma gin bea ing sho se ae. Mandible (Figu e 3I, J) wi h le and igh in‑
ciso s bea ing 5 and 4 den a e, espec i ely; le lacinia mobilis 4‑den a e, igh lacinia mobilis wi h 2 la ge
and se e al small den a e; accesso y se al ow comp ising 7 se ae on he le and 6 se ae on he igh ; mola
p ocess i u a i e wi h plumose se a; palp 3‑a icula e; a icle 1 wi hou se ae, a icle 2 and 3 wi h 12 and
15 se ae, espec i ely. Lowe lip (Figu e 3K) wi h ou e lobes la e ally expanded, bea ing apical se ae; inne
lobes ounded, educed. Maxilla 1 (Figu e 3L) wi h inne pla e bea ing 8 plumose se ae; ou e pla e wi h 9
den a e obus se ae; palp 2‑a icula e, ou e ma gins ba e. Maxilla 2 (Figu e 3M) inne pla e wi hou oblique
inne ow o se ae. Maxilliped (Figu e 3N) inne pla e bea ing plumose se ae on apical and inne ma gins,
wi h obus se a a inne dis al co ne ; ou e pla e obo a e, wi h 4 plumose se ae on apical ma gin, spa ula
plumose se ae on apical and inne ma gins, espec i ely, bea ing slende se ae on en al inne subma gin,
eaching h ee ou hs o palp a icle 2; palp 4‑a icula e, a icle 2 medial ma gin wi h 2 ows o se ae, apical
ma gin o a icle 3 and inne ma gin o a icle 4 co e ed wi h ine se ae.
Gna hopod 1 (Figu e 4A–C) en al ma gin o coxa wi h small se ae; basis an e io and pos e io ma gins
wi h long se ae, pos e odis al subma gin co e ed wi h ine se ae la e ally and medially; ischium and me us
pos e io ma gins co e ed wi h ine se ae la e ally and medially; ca pus leng h 1.6× leng h o p opodus,
Figu e 4. Meli a alluaudi Ledoye , 1982,
male, 9.1 mm (NSMT‑C 33011). A. Le
gna hopod 1, medial iew. B, C. Palma
ma gin o p opodus and dac ylus o le
gna hopod 1, la e al and medial iew,
espec i ely. D. Righ gna hopod 2, medial
iew. Scale ba s: A, D = 0.3 mm; B, C = 0.1
mm.
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Yoshimu a and Tomikawa · Meli a alluaudi om Japan 921
an e odis al co ne co e ed wi h ine se ae medially, and bea ing ow o weakly plumose se ae; p opodus
an e odis al p ojec ion o ming ec angula hood, co e ing dac ylus (Figu e 4B, C), wi h 2 (le gna hopod
1) o 3 ( igh gna hopod 1) obus se ae a he base o an e odis al p ojec ion p ojec ing e ically owa d
he medial side, pos e odis al co ne wi h 2 obus and 7 slende se ae, a ounded hump a he base o
pos e odis al co ne ising e ically in he medial di ec ion; ip o dac ylus di ec ed medially, an e op oxi‑
mal ma gin, an e odis al ma gin, and pos e odis al ma gin wi h se a, espec i ely. Gna hopod 2 (Figu e 4D)
en al ma gin o coxa wi h small se ae; basis pos e io ma gin wi h long se ae; p opodus sub ec angula ,
medial su ace wi h dense, slende se ae, wi h a idge unning om he base o dac ylus owa d medial
su ace, wi h 3 obus se ae on medial su ace be ween a idge and dac ylus, palma ma gin oblique wi h
a ow o obus se ae.
Pe eopods 3, 4 (Figu e 2A) en al ma gins o coxa wi h small se ae; basis an e op oximal and pos e io
ma gins wi h long se ae; dac ylus (Figu e 2C) wi h plumose se a on an e op oximal ma gin, a slende se a
on pos e io ma gin and a base o nail, espec i ely. Pe eopods 5–7 (Figu e 2A) basis expanded, an e io
ma gin bea ing a se ies o small obus se ae, pos e io ma gin weakly se a e; me us weakly expanded,
leng h 1.8, 1.8, 2.0× wid h, espec i ely; dac ylus (Figu e 2D) wi h plumose se a on pos e op oximal ma gin,
wi h slende se a on an e io ma gin and a he base o nail, espec i ely; coxal pla e 5 bioba e, wi h small
se a on dis al ma gin o an e io lobe; coxal pla e 6 bioba e, wi h small se a on an e io ma gin o an e io
Figu e 5. Meli a alluaudi Ledoye , 1982,
(A–D) male, 9.1 mm (NSMT‑C 33011), (E–I)
emale, 6.2 mm (NSMT‑C 33012), and (J)
emale, 6.0 mm (NSMT‑C 33014). A. Le
u opod 1, la e al iew. B. Le u opod 2,
la e al iew. C. Le u opod 3, do sal iew.
D. Telson, do sal iew. E. Le gna hopod 1,
la e al iew. F. Palma ma gin o p opodus
and dac ylus o igh gna hopod 1, medial
iew. G. Le gna hopod 2, la e al iew. H.
Palma ma gin o p opodus and dac ylus
o igh gna hopod 2, medial iew. I, J.
Pe eopod 6 coxa, la e al iew. Scale ba s:
A–C, E, G = 0.3 mm; D, F, H–J = 0.1 mm.
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Yoshimu a and Tomikawa · Meli a alluaudi om Japan 922
lobe and pos e io ma gin o pos e io lobe, espec i ely; coxal pla e 7 semici cula , wi h small se a on pos‑
e io ma gin.
Coxal gills (Figu e 2A) p esen on gna hopod 2, and pe eopods 3–6.
U opod 1 (Figu e 5A) peduncle leng h 1.2× leng h o ami, wi h 8 do sola e al, 3 do somedial, and 1
baso acial obus se ae; ou e amus almos as long as inne amus, wi h 4 and 3 obus se ae on la e al
and medial ma gins, espec i ely, dis al pa wi h 4 obus se ae; inne amus wi h 3 la e al, 4 medial, and
5 apical obus se ae. U opod 2 (Figu e 5B) peduncle leng h 1.1× leng h o ou e amus, wi h 5 do sola e al,
and 2 do somedial obus se ae; ou e amus leng h 0.9× leng h o inne amus, wi h 5 and 2 obus se ae on
la e al and medial ma gins, espec i ely, dis al pa wi h 3 obus se ae; inne amus wi h 2 la e al, 3 medial,
and 4 apical obus se ae. U opod 3 (Figu e 5C) peduncle leng h 0.5× leng h o ou e amus; ou e amus
b oad, 2‑a icula e, a icle 1 la e al and medial ma gins wi h 6 and 8 clus e s o se ae, espec i ely; a icle 2
small, leng h 0.05× leng h o a icle 1.
Telson (Figu e 5D) leng h 1.1× wid h, cle , each lobe wi h 2 o 3 and 1 obus se ae on la e al and medial
ma gins, espec i ely, dis al pa wi h 5 obus , 2 plumose, and 1 slende se ae.
Sexually dimo phic cha ac e s o wo emales: 6.2 mm (NSMT‑C 33012); 6.0 mm (NSMT‑C 33014).
Gna hopod 1 (Figu e 5E, F) ca pus leng h 1.3× leng h o p opodus; p opodus an e odis al co ne no p ojec ‑
ed, palma ma gin e ical, pos e odis al co ne wi h 2 o 3 obus se ae medially. Gna hopod 2 (Figu e 5G,
H) p opodus subo a e, medial su ace wi h a ew slende se ae, palma ma gin oblique wi h 8 obus se ae
la e ally, and 2 o 3 obus se ae on palma co ne .
Coxal pla e 6 (Figu e 5I, J) an e io lobe dep h 1.3× wid h o coxa, s ongly hooked, wi h 2 o 3 se ae on
an e io ma gin.
Oos egi es (Figu e 5G) p esen on gna hopod 2, and pe eopods 3–5, na ow wi h se ae.
Colo a ion in li e. Body gene ally anslucen (Figu e 6); eyes black; an ennae 1 and 2 peduncle a icles
dis ally b own.
Va ia ion. Accesso y lagellum o an enna 1 4‑ o 5‑a icula e. Rounded hump a base o male gna hopod
1 p opodus pos e odis al co ne indis inc in he 7.5 mm male (NSMT‑C 33013).
Dis ibu ion. Madagasca : Tôlana o (Ledoye 1982). China: Daya Bay, Guangdong; Linchang Ree , Hainan
(Ren 2012). Japan: Yonaguni Island, Okinawa (p esen s udy) (Figu e 1A).
Iden i ica ion. The specimens in he p esen s udy ag ee well wi h he o iginal desc ip ion o M. alluaudi
by ha ing he ollowing ea u es: 1) u osomi e 1 do sal ma gin no p oduced; 2) u osomi e 2 wi h a minu e
do sal oo h and 3 obus se ae on each side; 3) epime al pla e 3 pos e odis al co ne p oduced; 4) male
gna hopod 1 p opodus an e odis al p ojec ion o ming ec angula hood, co e ing he dac ylus; 5) male
gna hopod 2 p opodus sub ec angula ; 6) u opod 3 ou e amus b oad, 2‑a icula e; and 7) elson wi h o‑
bus se ae on la e al ma gin. The o iginal desc ip ion o M. alluaudi p o ides only limi ed mo phological
in o ma ion because he desc ip ion is e y b ie and se e al appendages a e unillus a ed. None heless,
he p esen specimens exhibi he abo e diagnos ic ea u es consis en wi h he o iginal desc ip ion, and no
dis inguishing di e ences we e ound. The e o e, he specimens a e iden i ied as M. alluaudi.
Figu e 6. Meli a alluaudi Ledoye , 1982,
male (NSMT‑C 33011) held emale (NSMT‑C
33012) in p ecopula. Scale ba : 1.0 mm.
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Yoshimu a and Tomikawa · Meli a alluaudi om Japan 923
Key o species o Meli a om Japan
1 U opod 3 ou e amus 1‑a icula e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
– U opod 3 ou e amus 2‑a icula e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2 Pleoni es 1–3 each wi h do sal ee h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. ube cula a Naga a, 1965
– Pleoni es 1–3 wi hou do sal ee h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3 Eyes absen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. miyakoensis Tomikawa & Aoyagi, 2022
– Eyes p esen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4 An ennal sinus o head absen ; pe eopods 3 and 4 wi h long, eeble dac yli . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. longidac yla Hi ayama, 1987
– An ennal sinus o head p esen ; pe eopods 3 and 4 wi h sho , s ou dac yli . . . . . . . . . . . . . . . . . . . . . . . . 5
5 An ennal sinus o head incised . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
– An ennal sinus o head ounded o igh ‑angled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6 An enna 2 lagellum densely se ose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. se i lagella Yama o, 1988
– An enna 2 lagellum spa sely se ose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7 Body black‑and‑whi e; an e odis al p ojec ion o male gna hopod 1 p opodus ully co e ing dac ylus .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. panda Tomikawa, Yama o & A iyama, 2024
– Body almos all g ay; an e odis al p ojec ion o male gna hopod 1 p opodus no comple ely co e ing
dac ylus ...................................................................................... 8
8 U osomi e 2 wi hou do sal ee h ...................................... M. ko eana S ephensen, 1944
– U osomi e 2 wi h a minu e do sal oo h on each side .............................................. 9
9 Male gna hopod 1 p opodus wi h obus se a on palma co ne , lacking obus se ae on medial su ace;
emale coxa 6 deepe han wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. naga ai Yama o, 1987
– Male gna hopod 1 p opodus wi hou obus se a on palma co ne , bea ing obus se ae on medial
su ace; emale coxa 6 shallowe han wide ............................ M. bingoensis Yama o, 1987
10 Telson sho e han wide ..................................... M. nunomu ai Tomikawa & Sasaki, 2022
– Telson as long as o longe han wide ............................................................. 11
11 Male gna hopod 1 p opodus wi h an e odis al hood; emale coxa 6 deepe han wide; emale coxae 1
and 2 wi h conca i y in an e io edge bea ing nume ous se ae ...................................
..................................................... M. ogasawa aensis Tomikawa & Sasaki, 2022
– Male gna hopod 1 p opodus wi hou an e odis al hood; emale coxa 6 wide han deep; emale coxae 1
and 2 wi hou conca i y in an e io edge ...................................................... 12
12 Male u opod 3 ou e amus app oxima ely 5× wid h; emale coxa 6 wide han deep ..................
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. shimizui (Uéno, 1940)
– Male u opod 3 ou e amus longe han 7× wid h; emale coxa 6 as wide as dep h .................. 13
13 Male gna hopod 2 p opodus p oximally ele a ed; emale gna hopod 2 basis wi h small palma e se ae .
M. okinawaensis Tomikawa & Nakano, 2022
– Male gna hopod 2 p opodus no p oximally ele a ed; emale gna hopod 2 basis wi hou small palma e
se ae . . . . . . . . . . . . . . . . . . . . . . . . . . . M. choshigawaensis Tomikawa, Hi ashima, Hi ai & Uchiyama, 2018
14 U opod 3 ou e amus wi h long se ae ................................ M. quad iden a a Yama o, 1990
– U opod 3 ou e amus wi hou long se ae ......................................................... 15
15 Maxilla 1 palp a icle 1 wi hou se ae; male gna hopod 2 p opodus wi h squa ish palma co ne ...... 16
– Maxilla 1 palp a icle 1 wi h se ae; male gna hopod 2 p opodus wi h ans e se palma ma gin ...... 17
16 Pleoni es 1–3 wi h do sal ee h .............................................. M. ylo ae Bulyče a, 1955
– Pleoni es 1–3 wi hou do sal ee h .......................................... M. alluaudi Ledoye , 1982
17 Se ae on maxilla 1 palp a icle 1 eaching dis al pa o palp a icle 2; pe eopods 5–7 wi h basis no ex‑
emely expanded, leng h mo e han 1.3× wid h ........................ M. hoshinoi Yama o, 1990
– Se ae on maxilla 1 palp a icle 1 no eaching dis al pa o palp a icle 2; pe eopods 5–7 wi h basis ex‑
emely expanded, leng h less han 1.3× wid h ..................... M. pilop opoda Hi ayama, 1987
DISCUSSION
Meli a alluaudi was o iginally desc ibed by Ledoye (1982) based on specimens om Madagasca . Subse‑
quen ly, Ren (2012) eco ded his species in sou he n China. The p esen s udy ep esen s he hi d eco d
o M. alluaudi and he i s eco d om Japan and he Philippine Sea. Ren (2012) desc ibed M. alluaudi based
on he specimens collec ed om benea h s ones on shallow co al ee s, and his desc ip ion shows no sig‑
ni ican di e ences om he ma e ial examined ou s udy. No ably, he en i onmen whe e Ren collec ed
Check Lis 21 (5) · h ps://doi.o g/10.15560/21.5.917
Yoshimu a and Tomikawa · Meli a alluaudi om Japan 924
his specimens is simila o he habi a in which ou specimens we e ound. Thus, by conduc ing su eys in
same habi a s, M. alluaudi could be disco e ed in o he egions whe e his species has no been eco ded.
The o iginal desc ip ion o M. alluaudi lacks mo phological in o ma ion o se e al appendages. Fo
example, maxilla 2 and emale coxa 6, which a e diagnos ic ea u es o o he Meli a species, we e no de‑
sc ibed. Since M. alluaudi has been subsequen ly eco ded om China and Japan, i is necessa y o cla i y i s
diagnos ic cha ac e s using ma e ials om bo h he ype locali y and newly eco ded egions. In he u u e,
i will be desi able o edesc ibe he ype ma e ial and supplemen he missing da a.
ACKNOWLEDGEMENTS
We a e g a e ul o Vjachesla S. Labay, Benoi Gouillieux, and Young‑Hyo Kim o hei cons uc i e and
aluable commen s on his manusc ip . We also hank Raquel Xa ie o edi ing a d a o his manusc ip .
We app ecia e he Na u al Science Cen e o Basic Resea ch and De elopmen o p o iding access o he
expe imen al equipmen .
ADDITIONAL INFORMATION
Con lic o in e es
The au ho s decla e ha no compe ing in e es s exis .
E hical s a emen
No e hical s a emen is epo ed.
Funding
This s udy was inancially suppo ed by he Japan Socie y o he P omo ion o Science (JSPS) h ough a
G an ‑in‑Aid o JSPS Fellows [25KJ1881] o HY and JSPS KAKENHI g an s [22K06373 and 23K22282] o KT.
Au ho con ibu ions
Concep ualiza ion: HY. Da a cu a ion: HY, KT. Fo mal analysis: HY. Funding acquisi ion: HY, KT. In es iga ion:
HY. Me hodology: HY, KT. Resou ces: HY. Supe ision: KT. Visualiza ion: HY. P ojec adminis a ion: HY, KT.
So wa e: HY. Valida ion: HY, KT. W i ing – o iginal d a : HY, KT. W i ing – e iew and edi ing: HY, KT.
Au ho ORCID iDs
Hi o Yoshimu a h ps://o cid.o g/0009‑0005‑1297‑4368
Ko Tomikawa h ps://o cid.o g/0000‑0003‑1521‑9016
Da a a ailabili y
All da a ha suppo he indings o his s udy a e a ailable in he main ex .
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