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Marine Biology (2023) 170:167
https://doi.org/10.1007/s00227-023-04305-1
ORIGINAL PAPER
Two new pygmy squids, Idiosepius kijimuna n. sp. andKodama jujutsu
n. gen., n. sp. (Cephalopoda: Idiosepiidae) fromtheRyukyu Islands,
Japan
AmandaReid1 · NoriyosiSato2,3· JereyJolly4,5· JanStrugnell6
Received: 10 February 2023 / Accepted: 12 September 2023 / Published online: 21 October 2023
© The Author(s) 2023
Abstract
Two new pygmy squid from the Ryukyu archipelago, Japan, are described: Kodama jujutsu, n. gen., n. sp. and Idiosepius
kijimuna, n. sp. They differ from all other nominal species in a combination of traits, including the number of tentacular
club suckers, shape of the funnel-mantle locking-cartilage, modification of the male hectocotylus and the structure of the
gladius and nuchal-locking cartilage, in addition to mitochondrial DNA markers (12S, 16S and COI). They are both known
from Okinawa Island and there is some overlap in their distributions. In a molecular phylogeny that includes all nominal
Idiosepiidae, Kodama jujutsu, n. gen., n. sp. is sister taxon to a clade containing Xipholeptos Reid & Strugnell, 2018 and
Idiosepius Steenstrup, 1881. Xipholeptos and Idiosepius are sister taxa. Idiosepius spp. now includes seven nominal species.
In addition, aspects of the behaviour of the new species are described.
Keywords Pygmy squid· Kodama· Idiosepius· Idiosepius kijimuna· Kodama jujutsu· Ryukyu archipelago
Introduction
In a recent study of Idiosepius Steenstrup, 1881 an unde-
scribed species was recognised from Okinawa, Japan based
on morphological and molecular traits (Reid and Strugnell
2018). It was represented by two males and a single female
specimen held in the Australian Museum collections. The
focus in Reid and Strugnell (2018) was on the Australian
representatives of the family and because only two preserved
specimens were available for examination at the time, the
species was not formally described and was recognised as
‘Okinawa’ n. sp. (Reid and Strugnell 2018: 472). Since then,
more specimens have been collected enabling the species
to be fully described here. It has been found at a number of
locations in the Ryukyu Island archipelago, ranging from
off Hamamoto, Okinawa Island in the north, and south to
Sakiyama Bay, Iriomote Island.
Subsequently, a second idiosepiid was found in the region
that did not appear to conform to other known idiosepiids. It
shares some morphological traits with the southern Austral-
ian endemic Xipholeptos notoides (Berry, 1921). Both of the
Japanese taxa were included in a molecular analysis with
representatives of all known Idiosepiidae. The taxa within
this family have historically proved difficult to identify based
only on morphology (von Byern and Klepal 2010) but the
Responsible Editor: R. Rosa.
[Version of record, published online 21 October 2023; http:// zooba
nk. org/ urn: lsid: zooba nk. org: pub: EAAF7 947- 9DE4- 4958- 8FAC-
44A0E 431FB 8C].
* Amanda Reid
mandyreid7@gmail.com
* Jeffrey Jolly
Jeffrey.a.jolly@gmail.com
1 School ofEarth, Atmospheric andLife Sciences, Faculty
ofScience, Medicine andHealth, University ofWollongong,
Wollongong, NSW2522, Australia
2 Oki Marine Biological Station, Shimane University, Oki,
Japan
3 Department ofFisheries, School ofMarine Science
andTechnology, Tokai University, Shizuoka, Japan
4 Molecular Genetics Unit, Okinawa Institute ofScience
andTechnology Graduate University, Onna,
Okinawa904-0495, Japan
5 Marine Climate Change Unit, Okinawa Institute
ofScience andTechnology Graduate University, Onna,
Okinawa904-0495, Japan
6 Centre forSustainable Tropical Fisheries andAquaculture,
James Cook University, Townsville, QLD4811, Australia
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Marine Biology (2023) 170:167
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167 Page 2 of 26
application of molecular tools is facilitating a much better
understanding of species boundaries and uncovering some
hitherto interesting systematic depth within the family (von
Byern etal. 2012; Reid and Strugnell 2018).
Both taxa are described below with some behavioural
observations based on wild and laboratory-reared animals.
Live animal videos of both species are included in the Sup-
plementary information. These observations are compared
with what is currently known about other members of the
family.
Material andmethods
Morphology
Terminology, measurements, indices, and abbreviations for
anatomical structures follow Reid and Strugnell 2018 (based
on Roper and Voss 1983) and are listed in Table1. All meas-
urements are in millimetres (mm). Measurements and counts
for individual mature specimens of the new species are pre-
sented in Tables3, 4, 6 and 7; the range of values for each
character is expressed in the descriptions and in Tables2 and
5 as: minimum–mean–maximum (SD). The values for each
sex are given separately. In the case of discrete probability
distributions, such as sucker-counts, standard deviations
are not provided in cases where counts are few in number
because these cannot be calculated using the same formula
as can be applied to normally distributed data.
For scanning electron microscopy, arms, clubs and radu-
lae were removed, mounted, then air dried and examined in a
Zeiss Evo LS15 SEM using a Robinson Backscatter detector.
Soft structures were mounted directly on carbon tape and air
dried; some radulae and gladii were mounted on glass cov-
erslips prior to SEM. Photomicrography using a compound
microscope was also used to illustrate some structures.
Other abbreviations
AMS, Australian Museum, Sydney; NSMT, National
Museum of Nature and Science, Tokyo, Japan; WAM, West-
ern Australian Museum, Perth.
Table 1 Description of measurements and counts
Definitions largely follow Roper and Voss (1983). Indices (shown in square brackets) are calculated by expressing each measure as a percentage
of mantle length
Arm Length—AL: length of each designated (i.e. 1, 2 etc.) arm measured from first basal (proximal-most) sucker to distal tip of arm (Arm 1,
dorsal; 2, dorso-lateral; 3, ventro-lateral; 4, ventral) [ALI]
Arm Length left hectocotylus—AL4l: length of left hectocotylised arm in males [AL4lI]
Arm Length right hectocotylus—AL4r: length of right hectocotylised arm in males [AL4rI]
Sucker Count ASC: total number of suckers on each designated arm (e.g. ASC2)
Arm Sucker Count hectocotylus—ASC4r: number of suckers on proximal end of hectocotylised right ventral arm
Arm Sucker Count hectocotylus—ASC4l: number of suckers on proximal end of hectocotylised left ventral arm
Arm Sucker diameter—AS: diameter of largest normal sucker on each designated (i.e. 1, 2 etc.) arm [ASIn]
Club Length—ClL: length of tentacular club measured from proximal-most basal suckers (carpus) to distal tip of club [ClLI]
Club Row Count—ClRC: number of suckers in transverse rows on tentacular club
Club Sucker diameter—ClS: diameter of largest sucker on tentacular club [ClSI]
Egg Diameter—EgD: diameter of largest egg present in the ovary or oviduct [EgDI]
Eye Diameter—ED: diameter of eye [EDI]
Fin Insertion anterior—FIa: anterior origin of fin measured from mantle margin to anterior-most junction of fin and mantle [FIIa]
Fin Length—FL: maximum length of single fin [FLI]
Fin Width—FW: greatest width of single fin [FWI]
Free Funnel length—FFu: the length of the funnel from the anterior funnel opening to the point of its dorsal attachment to the head [FFuI]
Funnel Length—FuL: the length of the funnel from the anterior funnel opening to the posterior margin measured along the ventral midline
[FuLI]
Gill Lamellae Count—GLC: number of lamellae on one side of each demibranch (excluding the terminal lamella)
Gill Length—GilL: length of the gill measured from terminal lamella to origin of gill [GilLI]
Head Length—HL: dorsal length of head measured from point of fusion of dorsal arms to anterior tip of nuchal cartilage [HLI]
Head Width—HW: greatest width of head at level of eyes [HWI]
Mantle Length—ML: dorsal mantle length. Measured from anterior-most point of mantle to posterior apex of mantle
Mantle Width—MW: greatest width of mantle [MWI]
Ventral Mantle Length—VML: length of ventral mantle measured along ventral midline [VMLI]
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Marine Biology (2023) 170:167
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Taxon sampling andDNA isolation
Specimens were collected at night by wading, snorkelling,
or on SCUBA from shore at Hamamoto (26° 40′ 17.90″ N,
127° 53′ 17.05″ E), Sunabe (26° 19′ 41.09′′ N, 127° 44′
35.98′′ E), Maeda (26° 26′ 43.54′′ N, 127° 46′ 20.01′′ E),
Onna Point (26° 40′ 17.90.4′′ N, 127° 50′ 28.78′′ E), Miy-
agi (26° 22′ N, 127° 59′ E), and Kaichyu-doro (26° 19′ N,
127° 55′ E) near Okinawa Island and Sakiyama Bay (24°
19′ N, 123° 40′ E) and Shirahama (24° 22′ N, 123° 44′ E)
near Iriomote Island. Adults of both species were collected
using dipnets or 200ml transparent plastic containers. After
collection they were transferred to 20L buckets of fresh
seawater and aerated with a battery powered bubbler and
immediately transported to the Okinawa Institute of Science
and Technology where they were gradually acclimated over
one hour to 20°C and other aquarium parameters and condi-
tions used by Jolly etal. (2022). Adults were kept in a 70 L
tank where they were observed until sacrificed. They were
first transferred to a 500ml container of filtered seawater and
anaesthetised in a magnesium chloride solution (Abbo etal.
2021). Magnesium chloride was gradually added to a final
concentration of 7% over 30min. After no response to pinch-
ing stimuli and total cessation of breathing was observed, a
small fin clip biopsy was performed for DNA extraction. The
animal was then transferred to 4% methanol free paraform-
aldehyde in seawater and fixed for 72h at 4°C with gentle
rocking. Specimens were then transferred to 70% ethanol
for long-term preservation. Some specimens were fixed and
preserved in 95% ethanol.
Freshly collected specimens were used for molecular
study and analyses. Previously sequenced individuals were
used to increase sample size with specimen data obtained
from GenBank. Taxon names applied were those assigned
by Reid and Strugnell (2018) and include: Xipholeptos
notoides (Berry, 1921); I. hallami Reid and Strugnell 2018;
I. minimus d’Orbigny in Férrusac and d’Orbigny 1835; I.
paradoxus (Ortmann, 1888); I. picteti (Joubin, 1894); I. pyg-
maeus Steenstrup, 1881, and I. thailandicus Chotiyaputta
etal, 1991. As used in that analysis, Semirossia patagonica
(Smith, 1881) was selected as the outgroup taxon because
among available mtDNA genomes, the Idiosepius sequence
shows greatest similarity to that of Semirossia (Hall etal.
2014) and in addition, a sister taxon relationship between
Idiosepiidae and Sepiolida is supported in the literature
(Strugnell etal. 2017). Tissue from 16 new individuals that
included both suspected new species was sampled (See
Appendix Table9). DNA was extracted using commercial
kits (NucleoSpin; Machery-Nagel, Germany or DNeasy
Blood & Tissue Kit; Qiagen, Hilden, Germany) according
to the manufacturer’s protocols.
PCR amplification andnucleotide sequencing
Partial sequences of three mitochondrial genes; 12S rRNA,
16S rRNA and cytochrome c oxidase subunit I (COI) were
amplified in this study. Primers and annealing temperatures
are detailed in Allcock etal. (2008). PCR was performed in
a 20µL volume, containing 2.0µL Ex Taq buffer, 1.6µL
of dNTP, 0.1µL of TaKaRa Ex Taq DNA Polymerase
(TaKaRa), 1.0µL of each primer, 12.3µL of distilled H2O
and 2.0µL template DNA. PCR products were sequenced
by a commercial sequencing service (Fasmac, Japan) in both
directions.
Table 2 Idiosepius kijimuna n.
sp. ranges of arm length indices
(ALI), arm sucker diameter
indices (ASIn) and arm sucker
counts (ASC) of ten mature
males and ten mature females
min. minimum, max. maximum, R right, L left
Males Females
Min. Mean Max. SD Min. Mean Max. SD
ALI1 21.6 24.5 29.2 2.3 16.4 21.6 28.2 3.7
ALI2 24.6 29.0 35.1 3.5 20.0 24.8 29.5 3.5
ALI3 24.6 28.9 37.5 4.2 20.0 25.1 28.6 2.8
ALI4R 37.0 48.2 61.4 7.2 22.0 26.7 31.8 3.0
ALI4L 35.8 44.0 58.3 6.3
ASIn1 1.5 2.7 3.5 0.7 2.1 2.4 3.1 0.4
ASIn2 1.6 2.6 3.6 0.6 2.0 2.4 3.6 0.4
ASIn3 1.6 2.5 3.3 0.6 2.0 2.6 3.6 0.6
ASIn4 1.6 2.5 3.6 0.7 1.7 2.3 2.6 0.3
ASC1 13 17 20 2 20 25 30 3
ASC2 18 20 24 2 24 27 31 2
ASC3 16 19 24 2 22 26 32 3
ASC4r 2 34 1 22 26 30 2
ASC4l 3 56 1
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Marine Biology (2023) 170:167
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Molecular sequence analyses
DNA sequences were compiled in Geneious v 9.0.5 and
sequences were aligned using MAFFT v7.222 (Katoh and
Kuma 2002). PartitionFinder v1.1.1 (Lanfear etal. 2012)
was used to select best-fit partitioning schemes and evo-
lutionary models for the genes contained within the align-
ment. Maximum likelihood phylogenies were estimated for
all datasets using PhyML (Guindon and Gascuel 2003), IQ-
TREE (Nguyen etal. 2015) implemented within the W-IQ-
TREE web interface (Trifinopoulos etal. 2016) and also
RAxML (Stamatakis 2014) implemented within the RAxML
BlackBox web server (Stamatakis etal. 2008).
Results
Phylogenetic analysis
The best fit model was one where all three genes were con-
tained within a single partition. The evolutionary model
with the lowest BIC values was the Hasegawa-Kishino-
Yano Model (HKY) + I + G (Hasegawa etal. 1985). The total
evidence tree obtained from the sequence data is shown in
Fig.1.
A number of well-supported clades were retrieved from
the analysis, with clear structuring within some of the
larger clades. Two clades that include the newly sequenced
Table 3 Idiosepius kijimuna n. sp.: measurements (mm), counts and indices of 10 mature male specimens
Specimen Paratype
AMS
C.575592
Paratype
NSMT-Mo
85879
Paratype
NSMT-Mo
85880
Paratype
NSMT-Mo
85878
Paratype
NSMT-Mo
85879
NSMT-Mo
85926
NSMT-Mo
85924
Paratype
NSMT-Mo
85877
NSMT-Mo
85923
Holotype
NSMT-Mo
85928
ML 5.4 5.6 5.7 6.0 6.2 6.2 6.5 6.6 7.4 8.1
MWI 61.1 60.7 70.2 63.3 69.4 59.7 46.2 57.6 56.8 48.1
VMLI 83.3 80.4 84.2 80.0 80.6 80.6 83.1 75.8 83.8 79.0
FWI 29.6 26.8 28.1 25.0 25.8 22.6 24.6 22.7 20.3 19.8
FIIa 74.1 78.6 71.9 75.0 64.5 74.2 80.0 75.8 77.0 71.6
FLI 38.9 39.3 42.1 33.3 35.5 37.1 38.5 33.3 31.1 37.0
FuLI 24.1 26.8 29.8 28.3 24.2 29.0 21.5 22.7 32.4 27.2
FFuI 16.7 14.3 14.0 16.7 16.1 16.1 21.5 13.6 17.6 12.3
HLI 41.7 41.1 43.9 50.0 36.3 48.4 46.2 51.5 47.3 39.5
HWI 57.4 57.1 66.7 56.7 59.7 45.2 42.3 50.0 45.9 39.5
EDI 14.8 8.9 8.8 8.3 8.1 11.3 8.5 13.6 10.8 8.6
AL1I 24.1 22.3 26.3 29.2 24.2 25.8 26.2 22.7 23.0 21.6
AL2I 27.8 28.6 35.1 33.3 32.3 27.4 24.6 28.0 28.4 24.7
AL3I 27.8 26.8 35.1 37.5 29.0 27.4 24.6 28.8 27.0 24.7
AL4rI 55.6 50.0 61.4 50.0 48.4 43.5 41.5 51.5 43.2 37.0
AL4lI 46.3 37.5 43.9 58.3 44.4 40.3 47.7 41.7 43.9 35.8
ASIn1 2.78 3.04 3.51 3.33 3.23 2.42 1.85 3.03 2.03 1.54
ASIn2 2.78 3.57 2.98 3.33 3.23 1.94 1.85 3.03 2.03 1.60
ASIn3 2.78 2.68 2.63 3.33 3.23 1.94 1.85 3.03 2.03 1.60
ASIn4 2.22 3.57 2.63 3.33 3.23 1.94 1.85 3.03 2.03 1.60
ASC1 15 17 13 16 16 18 20 18 18 17
ASC2 18 18 20 20 18 23 22 20 24 21
ASC3 16 18 18 20 17 20 24 21 20 20
ASC4r3232234343
ASC4l3354546664
ClLI 42.6 30.4 31.6 36.7 30.6 27.4 32.3 31.8 37.8 27.2
ClRC2222222222
CSC 32 36 34 32 32 38 40 32 39 33
ClSI 2.78 1.79 2.11 2.00 1.94 1.61 1.85 1.82 1.69 1.48
GilLI 25.9 17.9 24.6 25.0 24.2 27.4 26.2 22.7 28.4 24.7
GilLC 15 17 17 18 18 15 18 14 15 18
SpLI 32.4 31.4 30.7 28.7 30.6 − − 33.3 − −
SpWI 2.2 2.1 2.1 2.0 2.4 − − 1.89 − −
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Marine Biology (2023) 170:167
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taxa from the Ryukyu archipelago, are clearly distinct and
well-supported. Xipholeptos notoides (IQ-tree bootstrap
[IQ-BS] = 100%; RAxML bootstrap [R-BS], R-BS = 100%,
PhyML bootstrap P-BS = 100%) was sister-taxon to a clade
containing all Idiosepius (IQ-tree bootstrap [IQ-BS] = 98%;
RAxML bootstrap [R-BS], R-BS = 77%, PhyML bootstrap
P-BS = 93%). As reported in Reid and Strugnell (2018), the
branch length separating X. notoides from Idiosepius is long
relative to the branch lengths within Idiosepius indicating
considerable molecular divergence.
Also on a long branch is a clade that includes one of the
newly discovered Okinawan idiosepiids (IQ-tree bootstrap
[IQ-BS] = 100%; RAxML bootstrap [R-BS], R-BS = 100%,
PhyML bootstrap P-BS = 100%). This taxon is sister to the
southern Australian endemic X. notoides and Idiosepius spp.
Together with some significant morphological traits, deep
evolutionary divergence is suggested based on analysis of
the molecular data. For these reasons we place the members
of this clade in its own genus, Kodama n. gen. as described
below.
The second Japanese taxon forms a well-supported
clade within Idiosepius (IQ-tree bootstrap [IQ-BS] = 100%;
RAxML bootstrap [R-BS], R-BS = 91%, PhyML bootstrap
P-BS = 99%). Members of this clade are recognised and
described below as a new species, Idiosepius kijimuna n.
sp. It includes the taxa referred to as ‘Okinawa’ n. sp. in
Reid and Strugnell (2018) and is sister to Idiosepius mini-
mus. This clade shows some considerable internal structure,
particularly among three termini that have a high support
value on a relatively long branch (IQ-tree bootstrap [IQ-
BS] = 92%; RAxML bootstrap [R-BS], R-BS = 82%, PhyML
bootstrap P-BS = 84%).
Table 4 Idiosepius kijimuna n. sp.: measurements (mm), counts and indices of 10 mature female specimens
Specimen NSMT-Mo
85925
NSMT-Mo
85921
NSMT-Mo
85884
Paratype
NSMT-Mo
85876
NSMT-Mo
85929
NSMT-Mo
85931
AMS
C.477896
NSMT-Mo
85922
NSMT-Mo
85930
NSMT-Mo
85927
ML 9.8 10.0 10.0 10.3 11.0 11.0 11.2 11.4 11.5 11.8
MWI 63.3 52.0 61.0 58.3 57.3 56.4 62.5 54.4 56.5 56.8
VMLI 78.6 85.0 85.0 81.6 72.7 80.0 80.4 78.9 82.6 82.2
FWI 18.4 17.0 18.0 22.3 13.6 18.2 23.2 15.8 20.0 15.3
FIIa 78.6 78.0 70.0 73.8 69.1 66.4 67.9 71.9 69.6 72.0
FLI 34.7 35.0 38.0 31.1 27.3 33.6 35.7 32.5 36.5 29.7
FuLI 25.5 30.0 25.0 28.2 25.5 22.7 20.5 20.2 21.7 27.1
FFuI 13.3 13.0 14.0 14.6 13.6 12.7 13.4 12.3 13.9 15.3
HLI 35.7 32.0 30.0 35.0 28.2 38.2 28.6 35.1 32.2 29.7
HWI 40.8 41.0 47.0 45.6 36.4 40.0 40.2 39.5 39.1 38.1
EDI 8.2 7.0 8.0 11.7 6.4 8.2 8.9 7.9 8.7 8.5
AL1I 23.0 20.0 25.0 28.2 16.4 22.7 24.1 21.9 17.4 17.8
AL2I 25.5 20.0 29.5 29.1 22.7 26.4 28.6 21.9 21.7 22.0
AL3I 27.0 27.0 27.0 25.2 21.8 27.3 28.6 24.6 20.0 22.9
AL4I 23.5 27.0 25.0 27.2 26.4 31.8 31.3 26.3 26.1 22.0
ASIn1 2.24 2.50 3.00 2.14 2.27 2.27 3.13 2.19 2.17 2.12
ASIn2 2.04 2.50 2.60 2.62 2.27 2.27 3.57 2.19 2.17 2.12
ASIn3 2.04 2.50 3.60 2.91 2.27 2.27 3.57 2.19 2.17 2.12
ASIn4 2.55 2.50 2.40 2.62 2.27 1.82 2.41 2.19 2.61 1.69
ASC1 24 22 27 24 20 26 30 24 26 27
ASC2 30 26 26 27 26 31 24 26 25 28
ASC3 24 26 22 27 24 32 24 28 28 28
ASC4 27 28 28 26 22 30 24 24 26 28
ClLI 35.7 33.0 35.0 32.0 32.7 36.4 33.9 39.5 34.8 35.6
ClRC2222222222
CSC 50 48 42 45 48 51 44 48 47 49
ClSI 2.0 2.0 2.4 1.9 1.8 1.8 2.2 1.8 2.2 1.7
GilLI 30.6 25.0 30.0 22.3 27.3 20.0 18.8 26.3 27.8 29.7
GilLC 20 20 22 24 24 20 25 24 22 20
EgDI 8.2 10.0 10.0 12.6 9.1 9.1 7.1 8.8 8.7 9.3
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Systematic descriptions
Idiosepius kijimuna n. sp.
(Figs.1, 2, 3, 4, 5, 6, Tables2, 3, 4, 8, Appendix Table9).
Common name: Ryukyu Pygmy Squid; Japanese name,
Ryukyu-himeika.
Material examined
Type material
Holotype: Japan, Okinawa I., Motobu Hamamoto [Penin-
sula], 26° 40′ N, 127° 53′ E, coll. J. Jolly: 1♂, 8.1mm ML,
22 Feb. 2019 (NSMT-Mo 85928).
Paratypes: Japan, Okinawa I., Motobu Hamamoto [Penin-
sula], 26° 40′ N, 127° 53′ E, coll. N. Sato: 1♀, 8.6mm ML,
26 Jan. 2007 (NSMT-Mo 85875); 1♀, 10.0mm ML, 19 Apr.
2007 (NSMT-Mo 85876); 1♂, 6.6mm ML, 1♀, 7.2mm
ML, 3 May 2007 (NSMT-Mo 85877); 3♂, 3.8–6.5mm ML,
4 May 2007 (NSMT-Mo 85878); 4♂, 4.0–6.2mm ML,
1♀, 5.6mm ML, 15 May 2007 (NSMT-Mo 85879); 5♂,
4.0–5.7mm ML, 1♀, 7.3mm ML, 18 May 2007 (NSMT-Mo
85880); 1♀, 7.4mm ML, 29 Aug. 2007 (NSMT-Mo 85881);
1♂, 5.2mm ML, 29 Oct. 2007 (NSMT-Mo 85882).
Other material examined
Japan: 4♀, 4.0–5.2mm ML, Iriomote I., Sakiyama Bay,
24° 19′ N, 123° 40′ E, coll. N. Sato, 26 Aug. 2014 (AMS
C.596044); 7♂, 6♀, Iriomote I., Shirahama, 24° 22′ N,
123° 44′ E, coll. N. Sato, 27 Aug. 2014 (AMS C.596045).
Okinawa I.: Kaichyu-doro, 26° 19′ N, 127° 55′ E, coll. N.
Sato: 1♂, 4.3mm ML, 25 Jun. 2007 (AMS C.596040); 1♀,
9.4mm ML, 3 Jul. 2007 (AMS C.596041). Miyagi I., 26° 22′
N, 127° 59′ E, coll. N. Sato: 1♂, 6.1mm ML, 1♀, 10.0mm
ML, 23 Jan. 2008 (NSMT-Mo 85884); 1♂, 6.5mm ML,
21 Feb. 2008 (AMS C.596042), 1♂, 5.2mm ML, 3 Jun.
2008 (AMS C.596043). Motobu Hamamoto [Peninsula], 26°
40′ N, 127° 53′ E, coll. N. Sato, 9 Dec. 2007 (NSMT-Mo
85883); 2♂, 7.3mm ML, 5.3mm ML, data as for previ-
ous specimen, 22 Mar. 2007 (AMS C.596039). Okinawa,
Hamamoto, 26° 40′ N, 127° 53′ E, coll. J. Jolly, 22 Feb.
2019: 1♂, 6.2mm ML (NSMT-Mo 85926); 1♂, 7.4mm
ML, 1♀, 6.9mm ML (NSMT-Mo 85923); 1♂, 6.5mm ML,
1♀, 6.2mm ML (NSMT-Mo 85924); 1♀, 10.0mm ML
(NSMT-Mo 85921); 1♀, 11.4mm ML (NSMT-Mo 85922);
1♀, 9.8mm ML (NSMT-Mo 85925); 1♀, 11.8mm ML
(NSMT-Mo 85927); 1♀, 7.8mm ML (NSMT-Mo 85929);
1♀, 11.5mm ML (NSMT-Mo 85930); 1♀, 11.0mm ML
(NSMT-Mo 85931); 1♀, 6.8mm ML (AMS C.596046);
1♀, 6.8mm ML (AMS C.596047); 1♀, 7.0mm ML (AMS
C.596048); 1♀, 9.3mm ML (AMS C.596049); 1♀, 6.0 mm
ML (AMS C.596050); 1♀, 6.5mm ML (AMS C.596051);
1♀, 8.5mm ML (AMS C.596052); 1♀, 7.0mm ML (AMS
C.596053); 1♀, 7.8mm ML (AMS C.596054); 3 juv.,
1.9–2.0mm ML (AMS C.596055). Motobu Pen. Bise, 26°
42′ 31″ N, 127° 52′ 42″ E, 26 May 2013, coll. H. Fuku-
mori, K. Hidaka & Y. Takano: 1♀, 11.2 mm ML (AMS
C.477896); 1♂, 5.4mm ML (AMS C.575592); 1♂, 4.7mm
ML (AMS C.575591).
Diagnosis
Tentacular club with two suckers in each transverse row;
total number of club suckers 32–40♂, 42–50♀. Male
Table 5 Kodama jujutsu n. sp.
ranges of arm length indices
(ALI), arm sucker diameter
indices (ASIn) and arm sucker
counts (ASC) of five mature
males and two mature females
min. minimum, max. maximum, R right, L left
Males Females
Min. Mean Max. SD Min. Mean Max. SD
ALI1 26.7 29.4 32.1 2.4 23.3 27.7 32.2 6.3
ALI2 26.7 37.9 47.2 7.6 25.2 32.7 40.2 10.6
ALI3 31.6 34.3 39.1 3.2 24.0 29.3 34.5 7.4
ALI4R 15.8 23.4 31.3 6.9 24.8 26.8 28.7 2.8
AL4L 16.7 22.7 28.1 4.3
ASIn1 1.7 2.3 2.8 0.5 1.9 2.1 2.3 0.3
ASIn2 2.3 2.6 2.8 0.2 2.3 2.3 2.3 0
ASIn3 2.1 2.5 2.8 0.3 2.3 2.6 2.9 0.4
ASIn4 1.7 2.3 2.8 0.5 2.3 2.6 2.9 0.4
ASC1 14 15 16 1 15 17 20 3
ASC2 18 21 25 3 23 23 24 1
ASC3 18 19 22 2 19 19 19 0
ASC4r 8 910 1 19 19 19 0
ASC4l 8 910 1
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Marine Biology (2023) 170:167
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hectocotylised arms 4 longer than remaining arms; right
ventral arm longer than left ventral arm (Fig.2a, b; Table2).
Female arms 1 shorter than remaining arms, rest similar in
length. Hectocotylus: male left ventral arm with 3–6 suckers
basally and large flap at tip of arm; right ventral arm with
2–4 suckers basally. GiLC males 14–18; females 20–25.
Description
Counts and indices for individual specimens are given in
Tables3 (males) and 4 (females). Ten mature male and ten
mature females were measured.
Mature males smaller than females: ML males
5.4–6.4–8.1mm (SD 0.8), females 9.8–10.8–11.8mm (SD
0.7). Mantle blunt-cylindrical (Fig.2a–c); MWI males
46.2–59.3–70.2mm (SD 7.8), females 52.0–57.8–63.3mm
(SD 3.5). Dorsal mantle not joined to head, ventral mantle
margin straight to slightly concave. Ventral skin tags pre-
sent, one on each side of head posterior to eyes (Fig.2d).
Fins small, rounded, length approximately one-third mantle
length, FLI males 31.1–36.6–42.1mm (SD 3.3), females
27.3–33.4–38.0mm (SD 3.3); positioned dorso-laterally on
posterior end of mantle, FIIa males 64.5–74.3–80.0mm (SD
4.3), females 66.4–71.7–78.6mm (SD 4.1); fin width ~ 20%
ML, FWI males 19.8–24.5–29.6mm (SD 3.2), females
13.6–18.2–23.2mm (SD 3.0); anterior and posterior margins
with well-developed lobes, lateral lobes crescentic.
Table 6 Kodama jujutsu n. sp.:
measurements (mm), counts
and indices of mature male
specimens
Specimen Paratype NSMT-
Mo 85933
Paratype NSMT-
Mo 85938
Paratype NSMT-
Mo 85940
Holotype NSMT-
Mo 85932
Paratype
NSMT-Mo
85939
ML 5.3 5.7 6.0 6.0 6.4
MWI 64.2 64.9 65.0 65.0 71.9
VMLI 75.5 87.7 80.0 81.7 89.1
FWI 28.3 28.1 31.7 33.3 25.0
FIIa 62.3 66.7 65.0 66.7 78.1
FLI 28.3 35.1 30.0 30.0 23.4
FuLI 45.3 43.9 41.7 46.7 45.3
FFuI 41.5 43.9 40.0 38.3 29.7
HLI 50.9 52.6 50.0 46.7 53.1
HWI 58.5 59.6 60.0 58.3 62.5
EDI 11.3 15.8 15.0 13.3 14.1
AL1I 32.1 31.6 26.7 28.3 28.1
AL2I 47.2 40.4 26.7 40.0 35.2
AL3I 35.8 31.6 33.3 31.7 39.1
AL4rI 28.3 15.8 16.7 25.0 31.3
AL4lI 22.6 21.1 16.7 25.0 28.1
ASIn1 2.83 2.28 2.08 1.67 2.73
ASIn2 2.83 2.63 2.50 2.50 2.50
ASIn3 2.83 2.63 2.08 2.67 2.34
ASIn4 2.83 2.63 2.08 1.67 2.34
ASC1 15 14 16 16 16
ASC2 18 20 24 25 19
ASC3 18 18 18 18 22
ASC4r 8 10 8 9 8
ASC4l 8 10 8 9 8
ClLI 41.5 70.2 75.0 83.3 35.2
ClRC 2 2 2 2 2
CSC 24 28 24 26 26
ClSI 3.4 2.6 2.1 2.5 2.7
GilLI 28.3 31.6 33.3 50 31.3
GilLC 15 15 16 15 16
SpLI 22.6 − 20.0 18.3 −
SpWI 2.26 − 2.33 1.67 −
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Funnel conical, base broad, tapered anteriorly (Fig.2e);
FuLI males 21.5–26.6–32.4 mm (SD 3.4), females
20.2–24.6–30.0mm (SD 3.3); free for about 1/3 of its
length, FFuI males 12.3–15.9–21.5mm (SD 3.4), females
20.2–24.6–30.0mm (SD 3.3). Funnel-locking cartilage
(Fig.2f), deep, oval, with defined outer rim. Mantle-lock-
ing cartilage (Fig.2g) compliments funnel member, an ear-
shaped lug, broadest posteriorly, tapering towards mantle
margin. Funnel valve small, flaplike, rounded anteriorly,
dorsal element broad, inverted V-shape with pointed ante-
rior tip; ventral elements ovoid (Fig.3a). Nuchal locking
cartilage oval, not well-defined, indistinct (Fig.3b).
Head broader than long in both sexes, HLI males
36.3–44.6–51.5mm (SD 4.9), females 28.2–32.5–38.2mm
(SD 3.4); HWI males 39.5–52.0–66.7mm (SD 8.7), females
36.4–40.8–47.0 mm (SD 3.2). Eyes large, EDI males
8.1–10.2–14.8mm (SD 2.4), females 6.4–8.3–11.7mm (SD
1.4); ventral eyelids free. Eye covered by corneal membrane.
Distinct, large olfactory pit on latero-posterior surface of
head, posterior and ventral to eyes, close to mantle opening.
Arms, broad basally, tapered distally, hectocotylised
arms much longer than unmodified arms in males 4.3.2.1 or
4.2.3.1 (Tables2 and 3), arm formula variable in females,
with arm 4 usually longest and arms 1 shorter than lateral
arms (Tables2 and 4). Arm length index of longest arm in
males (ALI4 right) 37.0–48.2–61.4mm (SD 7.2), females
(ALI4) 22.0–26.7–31.8mm (SD 3.0). All arms similar in
shape, U-shaped in section (Fig.3c). Sucker pedicels broad,
short, suckers joined closely to arms and club. Chitinous
inner ring of arm suckers without teeth, smooth or slightly
crenulated on inner margin (Fig.3d). Infundibulum with 2–3
rows of shallow cup-like broad-based pegs, innermost row
of pegs larger, slightly more elongate, cylindrical surround-
ing inner ring, more elongate on one side of the sucker than
the other; processes contain low papillae, outer-most sucker
rim processes rectangular, flat, radially arranged (Fig.3d,
e). Male and female arm suckers similar in size (Table2).
Sucker counts range from 13–24 on male normal arms,
20–32 in females. All arms connected by relatively shallow
webs, protective membranes absent.
Both ventral arms of males hectocotylised: (Fig.3f–h).
Right ventral arm with 2.0–3.0–4.0 suckers proximally
remainder of arm without suckers; aboral side of arm with
broad, thin, ventro-lateral flanges attached laterally on each
side of arm; flange broadest proximally, tapering to distal
tip of arm (Fig.3f). Right ventral arm slightly longer than
left ventral arm (Table2). Left ventral arm with 3.0–5.0–6.0
suckers proximally (generally a greater number of suckers
on left than on right ventral arm), remainder of arm without
suckers; distal tip of arm flattened forming a blunt tongue-
like flange and proximal to this a slightly shorter blunt flap;
in preserved specimens, distal flap often recurved to cover
distal tip of arm (Fig.3g, h).
Tentacles similar to arms in appearance, semicir-
cular in section; oral surface convex. Club relatively
long; ClLI males 27.2–32.8–42.6mm (SD 4.8), females
32.0–34.9–39.5mm (SD 2.2), cylindrical, tapers to blunt end
distally. Sucker-bearing face of club only slightly convex.
Suckers ~ 0.1–0.2mm diameter in centre of club, arranged
in two rows in both sexes. Total number of club suckers
in males 32.0–35.0–40.0 (SD 3); females 42.0–47.2–51.0.
Swimming keel on aboral side of carpus broad, extends
posteriorly beyond carpus. Keel forms groove on oral side.
Club sucker dentition (Fig.4a): inner ring without teeth;
infundibulum with 3 rows of pegs; shallow, cup-like distally
bearing numerous papillae. At periphery, pegs narrower and
with fewer papillae. Outer-most sucker rim processes flat-
tened, rectangular.
Table 7 Kodama jujutsu n. sp.: measurements (mm), counts and indi-
ces of mature female specimens
Specimen Paratype NSMT-Mo
85936
Paratype NSMT-Mo
85936
ML 8.7 12.9
MWI 72.4 69.8
VMLI 70.1 69.8
FWI 27.6 36.4
FIIa 64.4 54.3
FLI 51.7 48.1
FuLI 40.2 35.7
FFuI 20.7 17.8
HLI 40.2 37.2
HWI 54.0 48.1
EDI 14.9 12.4
AL1I 32.2 23.3
AL2I 40.2 25.2
AL3I 34.5 24.0
AL4I 28.7 24.8
ASIn1 2.3 1.9
ASIn2 2.3 2.3
ASIn3 2.9 2.3
ASIn4 2.9 2.3
ASC1 15 20
ASC2 24 23
ASC3 19 19
ASC4 19 19
ClLI 41.4 33.3
ClRC 2 2
CSC 35 34
ClSI 2.3 2.3
GilLI 34.5 29.5
GilLC 16 18
EgDI 6.9 11.6
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Table 8 Idiosepiidae nominal species distinguishing features
Species GiLC No. rows
club suck-
ers*
Total no.
club suck-
ers
No.
sucker
rows left
ventral
arm 4 ♂
No.
sucker
rows right
ventral
arm 4 ♂
Relative
lengths of
ventral arms
compared
with other
arms (males)
Female
rela-
tive arm
lengths
Hecto-
cotylus
left ventral
arm IV
(with flap)
Hectocot-
ylus right
ventral
arm 4
Other
Idiosepius
hallami
Reid abd
Strug-
mell,
2018
Status:
valid
Misidentifi-
cations: I.
paradoxus
14–18 ♂,
18–20 ♀
2 ♂,
2 ♀
27–37 ♂,
37–46 ♀
Sucker rim
pegs with
papillae
7–10 6–9 Arms 4
slightly
longer than
remaining
arms; arms
1 shortest,
arms 2 and
3 similar in
length
All simi-
lar in
length,
with
arms
1 only
slightly
shorter
than rest
Longer
than
right
with
large,
flap-like
lobe
attached
obliquely
ventro-
laterally
towards
distal tip
Shorter,
broader
than
remain-
ing arms
Strong
keels on
aboral
side
Tentacles pos-
sibly used for
spermatophore
transfer†
Radula rachid-
ian teeth
homodont
or bidentate
in repeating
series
Spermatophore
cement body
bipartite
I. kijimuna
n. sp.
Status:
valid
Misidentifi-
cations:
I. para-
doxus
14–18 ♂,
20–25 ♀
2 32–40 ♂,
42–50 ♀
3–6 2–4 Arms 1–3
similar
in length.
Arms 4
longer than
rest
Arms 1
shorter
than
rest.
Rest
similar
in length
Shorter
than
right.
Distal tip
of arm
with
blunt
tongue-
like
flange
and
proximal
to this a
slightly,
shorter
blunt flap
Keels on
aboral
side
Mate head-to-
head
Hectocotylus
used for trans-
ferring sper-
matophores
I. minimus
d’Orbigny
in Fér-
rusac and
d’Orbigny
1835
Status:
valid
Syn. I.
biserialis
Voss,
1962; I.
macro-
cheir
Voss,
1962
? 2–4 39 ♂,
32–44 ♀
4 4 4.3.2.1
Arms
4.5 × length
of remain-
ing arms
4.3.2.1 Left arm
shorter
than
right,
with two
small
flaps
separated
by a deep
cleft
Slightly
wider
than left
Keels on
aboral
side
Oral side of
ventral arms
in males with
dark pigment
spots
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167 Page 10 of 26
Table 8 (continued)
Species GiLC No. rows
club suck-
ers*
Total no.
club suck-
ers
No.
sucker
rows left
ventral
arm 4 ♂
No.
sucker
rows right
ventral
arm 4 ♂
Relative
lengths of
ventral arms
compared
with other
arms (males)
Female
rela-
tive arm
lengths
Hecto-
cotylus
left ventral
arm IV
(with flap)
Hectocot-
ylus right
ventral
arm 4
Other
I. para-
doxus
(Ortmann,
1888)
Status:
valid
Misidentifi-
cations:
‘Okinawa’
n. sp.
29 4 ~ 48.0 ♂;
54–62 ♀
3–7
suckers
basally;
3–7 on
right
ventral
arm
Similar in
length to
other arms
All simi-
lar in
length,
arms 1
and 4
slightly
shorter
than
remain-
ing arms
Same
length
as right,
semi-
circular
mem-
brane on
dorsal
side, tip
enlarged
as a
cap-like
cover
Same
length
as left;
slightly
thicker.
Keels on
aboral
side
Trans-
verse
ridges
and
grooves
orally
Tentacles as
thick as arms
Hectocotylus
used for trans-
ferring sper-
matophores
I. picteti
(Joubin,
1894)
Status:
question-
able
34 2–4 2 2 Much shorter
than other
arms.
Remain-
ing arms
similar in
length
Slender
and
bilobed
at tip.
Lobe
tiny
Shorter
and
thicker
than
left.
Strong
keels on
aboral
side
trans-
verse
ridges
and
grooves
on oral
side
I. pygmaeus
Steen-
strup,
1881
Status:
valid
Misidenti-
fications:
O. pyg-
maeus
28–30 ♂,
39–45 ♀
2**–4
**Hylle-
berg and
Natee-
wathana
(1991)
45–62 ♂,
51–63 ♀
1–4 (usu-
ally 1–3)
1–3 Much shorter
than other
arms.
Remain-
ing arms
similar in
length
Arm 1
shortest
Longer
than
right;
thinner
than
right,
slender;
with
trans-
verse
ridges
and
grooves
on oral
side;
bilobed
at tip.
Lobe
tiny
Shorter
than
left;
stout,
thick,
blunt.
Keels on
aboral
side;
fleshy
trans-
verse
ridges
on oral
side
Live animals
sometimes
reverse coun-
tershade: pale
dorsally, dark
ventrally
Males grasp
females during
mating
Hectocotylus
used for trans-
ferring sper-
matophores
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Gills with 14–16–18 (SD 1.6) lamellae per demibranch
in males, females with 20–22–25 (SD 2.0) lamellae per
demibranch; GiLI 17.9–24.7–28.4mm (SD 2.9) males,
18.8–25.8–30.6mm (SD 4.2) females.
Buccal membrane with six lappets and fringed inner
margin; suckers absent. Radula with seven transverse rows
of homodont teeth (Fig.4b). Rachidian teeth, and second
lateral teeth broad basally, tapering distally, second later-
als asymmetrical with cusp of displaced toward midline
of radula ribbon (Fig.4b, c), second lateral teeth triangu-
lar, pointed, symmetrical in shape; marginal teeth narrow,
scythe-like (Fig.4b).
Upper beak (Fig.4d) with short, triangular rostrum, and,
as for lower beak, flanked by row of smaller teeth. Lower
beak (Fig.4e) with large median rostrum, flanked on either
side with a row of similar-sized small teeth. Distinct dark
pigmentation restricted to rostrum of upper and lower beaks.
Table 8 (continued)
Species GiLC No. rows
club suck-
ers*
Total no.
club suck-
ers
No.
sucker
rows left
ventral
arm 4 ♂
No.
sucker
rows right
ventral
arm 4 ♂
Relative
lengths of
ventral arms
compared
with other
arms (males)
Female
rela-
tive arm
lengths
Hecto-
cotylus
left ventral
arm IV
(with flap)
Hectocot-
ylus right
ventral
arm 4
Other
I. thailandi-
cus
Chiti-
yaputta
etal.
(1991)
Status:
valid
Misidentifi-
cations:
I. biserialis
(SE Asia)
15–17 2 28–39 ♂,
32–45 ♀
2–7 2–5 Arms 4
1.5 × as
long as
arms 1–3
Arms 1
shortest
Slightly
shorter
than
right
Tiny flap
at tip of
arm
Slightly
longer
than
left.
Broad
with
keels on
aboral
side
Tentacles used
for transferring
spermato-
phores
Females light
brown, males
dark brown
Kodama
jujutsu n.
gen., n.
sp.
15–16 ♂,
16–18 ♀
2 ♂,
2 ♀
24–28 ♂
34–35 ♀
Sucker rim
pegs with
papillae
8–10 8–10 All similar
in length,
arms 4
slightly
shorter
than
remaining
arms
All simi-
lar
Similar to
right
Large,
flap-like
lobe
attached
obliquely
ventro-
laterally
towards
distal tip
Similar to
left. No
keels on
aboral
side
Body squat,
rounded
Males approach
females from
below when
mating
Hectocotylus
used for trans-
ferring sper-
matophores
Radula rachidian
teeth homo-
dont; first
lateral teeth
short, hooked
Xipholeptos
notoides
(Berry,
1921)
30♂,
28–30 ♀
2–3 ♂,
2–3 ♀
45–62 ♂
51–78 ♀
7–11 7–11 All similar
length
All
similar
length
Longer
than
right,
bifur-
cates at
tip
No keels
on abo-
ral side
Body narrow,
elongate
Radula rachidian
teeth homo-
dont
Spermatophore
cement body
with bipartite
structure
Data has been compiled from the examination of preserved specimens and published literature. Included taxa follow the taxonomic conclusions
reached in this paper and Reid and Strugnell (2018). Some information was derived from taxa now deemed to be in synonomy with valid spe-
cies. Misidentifications refer to those in previous publications, GenBank and likely among museum collections. Not all Idiosepius species have
yet been examined for all characters in the light of the taxonomy proposed in this paper and this should be a focus for future study
*These traits have been used historically to distinguish Idiosepius, but their usefulness is questionable (von Byern and Klepal 2010)
†To be confirmed. Traits for I. picteti were scored following examination of the purported holotype. (Table modified from Reid and Strugnell
(2018), Table5 to include new species.) See also generic diagnoses. Distinguishing generic characters are not tabulated here
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Marine Biology (2023) 170:167
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Male reproductive tract similar in structure to conge-
ners (not illustrated). Spermatophores approximately 1/3
mantle length; SpLI 28.7–31.2–33.3mm (SD 2.9), SpWI
1.9–2.1–2.4mm (SD 0.2). Sperm reservoir simple, with-
out coiled sperm cord. Cement body unipartite; aboral end
cup-shaped, cylindrical, oral end tapering toward ejaculatory
apparatus (Fig.4f). Oral end of ejaculatory apparatus with
3–4 simple coils.
Female reproductive tract: Ovary large, occupies
approximately half of mantle cavity. Eggs of various sizes
suggesting protracted multiple spawning. Ovary opens via
single thick-walled oviduct at anterior end on left side of ani-
mal. Nidamental glands paired, broad, leaf-shaped, located
ventral to ovary toward, and overlying anterior half. Acces-
sory nidamental glands absent. Eggs ovoid, 0.8–1.3mm
diameter; EgDI 7.1–9.3–12.6mm (SD 1.4).
Gladius reduced to a thin, ovoid, chitinous structure
embedded in ventral side of dorsal mantle below adhesive
pad; does not extend full length of mantle. Rachis absent.
Fig. 1 Maximum Likelihood phylogenetic tree generated using
PhYML (GTR + I + G) from the analysis of partial fragments of 12S
rRNA, 16S rRNA and CO1. Semirossia patagonica was used the out-
group. Bootstrap values (1000 replicates) were generated from maxi-
mum likelihood analysis using IQ-tree/RAMxML/PhyML. Taxon
names to the left of the shaded bar refer to the species names used in
GenBank records and associated publications, in addition to the new
taxa identified in this analysis. Taxon names to the right of the bar
are those we believe should be assigned to the studied taxa. Numbers
to the right of the taxon names refer to sample numbers correspond-
ing to individual specimens sequenced that are listed in the Appendix
Table 9; numbers in square brackets were sequenced for this study,
those without brackets correspond to specimens included in Reid and
Strugnell (2018)
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Preserved animals cream with purple chromatophores
evenly peppered dorsally and ventrally on mantle and arms,
largest on head (Fig.2a–c). Large chromatophores on arms
appear as block-like bands. Chromatophores on fins confined
to junction with mantle, do not extend to outer fin margins.
Ventral side of funnel with chromatophores. Chromato-
phores often in a row at distal tip. Chromatophores in tissue
overlying internal viscera. Live animals (Fig.5) mid-brown
to greenish brown with relaxed chromatophores giving a
predominantly uniform colouration (Fig.5a).
Type locality
Japan, Okinawa I., Motobu Hamamoto [Peninsula], 26° 40′
N, 127° 53′ E.
Distribution
Japan: Ryukyu Islands: Iriomote I., Sakiyama Bay, 24° 19′
N, 123° 40′ E to Okinawa, Motobu Pen. Bise, 26° 42′ 31″ N,
127° 52′ 42″ E (Fig.6).
Habitat andbiology
Idiosepius kijimuna have primarily been collected from shal-
low (less than 2m) seagrass beds in Okinawa in winter from
November to March. During this time, they have also been
observed, albeit rarely, in coral habitats. Their whereabouts
during the warmer months are largely unknown.
Etymology
The species name is used for creatures in Okinawan mythol-
ogy. The Kijimunā are said to be elfin creatures that make
their home in the banyan trees that grow over the Ryukyu
Archipelago. Their diet consists entirely of seafood and they
are excellent fishers. They avoid octopuses at all costs. The
name is used as a noun in apposition.
Remarks
Characters that distinguish I. kijimuna from Kodama jujutsu,
n. sp. n. gen. and X. notoides are provided in the Diagno-
sis and Remarks under K. jujutsu n. sp. n. gen. below. The
Fig. 2 Idiosepius kijimuna n.
sp. a dorsal view, male, 5.4mm
ML, AMS C.575592. b ventral
view, same specimen. c dorsal
view, female, 11.2mm ML,
AMS C.477896. d ventral
view of head showing ventro-
lateral skin tags (arrows), male,
5.4mm ML, AMS C.575592.
e funnel, paratype female,
8.6mm ML, NSMT Mo-85875.
f funnel-locking cartilage, para-
type male, 7.2mm ML, NSMT-
Mo 85881. g mantle-locking
cartilage, male as in f. Scale
bars: a, b = 1mm; c = 2mm;
d = 0.5mm; e = 1mm; f,
g = 200µm
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167 Page 14 of 26
combination of characters that separate I. kijimuna from
other nominal Idiosepius are provided in Table8.
The presence of relatively long male ventral arms is not
unique to I. kijimuna. This trait is shared by its sister taxon I.
minimus and also I. thailandicus. These three taxa together
form a well supported clade within the broader Idiosepius
clade (IQ-tree bootstrap [IQ-BS] = 97%; RAxML bootstrap
[R-BS], R-BS = 81%, PhyML bootstrap P-BS = 79%) that
appears to be sister to I. picteti (Fig.1).
Kodama n. gen.
Type species
Here designated. Kodama jujutsu, n. sp.
Diagnosis
Mantle-locking cartilage a straight ridge, funnel-locking
cartilage a corresponding straight, narrow furrow. Eight
to 10 pairs of suckers, extend along length of both ventral
Fig. 3 Idiosepius kijimuna n.
sp. a funnel organ stained with
methylene blue, paratype male,
7.2mm ML, NSMT-Mo 85881.
b nuchal cartilage, specimen
as in a. c SEM ventral view of
portion of arm crown (arms
1–3, numbered), paratype male,
6.0mm ML, NSMT-Mo 85878.
d SEM enlargement of arm 2
(left) and arm 3 (right) suckers,
specimen as in c. e enlargement
of individual sucker rim, arm 3
left, specimen as in c. f ventral
arms, male 5.4mm ML (AMS
C.575592). g SEM hectocoty-
lised left arm 4, paratype male
6.0mm ML, NSMT-Mo 85878.
h far left, hectocotylised left
ventral arm (tip recurved during
fixation), male AMS C.575592,
5.4mm ML. Scale bars: a,
b, = 200µm; c = 300µm,
d = 30µm, e = 3µm, f = 0.5mm.
g, h = 200µm
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Fig. 4 Idiosepius kijimuna n. sp.
a SEM, tentacular club sucker,
male paratype, 6.0mm ML,
NSMT-Mo 85858. b radula,
female, 10.2mm ML, AMS
C.477896. c enlargement of
portion of radula. d upper beak,
specimen as in b. e lower beak,
lateral view, specimen as in d.
f enlargement of oral end of
spermatophore, male, 6.5mm
ML, NSMT-Mo 85924. Scale
bars: a = 10μm; b, c = 1mm; d,
e = 2mm; f = 1mm
Fig. 5 Live Idiosepius kijimuna
n. sp. a, c swimming; b attached
to vegetation using dorsal
adhesive pad. Photosa, c © Jeff
Jolly; b© Brandon Hannan
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167 Page 16 of 26
arms in males; aboral side of right ventral arm not modified,
smooth; only left ventral arm modified as the hectocotylus.
Tentacular club with two rows of suckers in transverse rows.
Gills with 15–18 lamellae per demibranch. Rachidian teeth
of radula homodont; first lateral teeth short, much smaller
than other teeth and cusps low. Gladius extends full length of
mantle, paddle-shaped, narrow, pointed anteriorly, broadens
midway along its length; remainder of gladius, clear non-
sclerotised. Nuchal-locking cartilage distinct, well-defined.
Prominent skin tags, one on each side, posterior to eyes;
anterior to eyes on ventral side of head with pair of promi-
nent, small rounded, protruding papillae.
Etymology
The generic name Kodama refers to a tree spirit in Japanese
folklore. It has a reputation of being rounded in shape. The
presence of Kodama is a sign of a healthy forest. We have
chosen this name to suggest its extension to representing a
healthy reef.
Remarks
Some traits of Kodama n. gen. are shared with Xipholeptos.
Both of these monotypic taxa have a straight mantle-locking
cartilage, and the funnel-locking cartilage is a correspond-
ing straight furrow. Both have a medial rachis in the gladius
and the arms of males are all similar in length. The aboral
side of the right ventral arm is without a keel, and posterior
to the eyes is a pronounced skin tag. These traits separate
Kodama n. gen. and Xipholeptos from Idiosepius. However,
the distinct, folded bipartite structure seen in the aboral end
of the spermatophore cement body reported for X. notoides
in Reid and Strugnell (2018) is not present in Kodama n.
gen. In addition, the club has two transverse rows of suck-
ers in Kodama, n. gen. and four rows in Xipholeptos. The
body of Xipholeptos is cylindrical and elongate, while that
of Kodama is squat and rounded.
Kodama jujutsu, n. sp.
(Figs.1, 6, 7, 8, 9, 10, 11, 12, Tables5, 6, 7, 8, Appendix
Table9).
Fig. 6 Distribution of idiosepiids examined in this study: Idiosepius kijimuna n. sp. blue circles, Kodama jujutsu n. gen., n. sp. orange circles.
Shaded area on main map corresponds to Ryuku Isds inset in bottom right of figure
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Common name: Hannan’s Pygmy Squid; Japanese name
Tsuno-himeika.
Material examined
Type material
Holotype: Japan, Okinawa I, Hamamoto: 1♂, 6.0mm ML,
26° 40′ 17.90′′ N, 127° 53′ 17.05′′ E, 24 Feb 2019, coll. C.
Sugimoto and J. Jolly (NSMT-Mo 85932).
Paratypes: Japan: Okinawa I.: Miyagi I., 1♀, 6.8mm
ML, 26° 22′ N, 127° 59′ E, 23 Jan 2008, coll. N. Sato
(NSMT-Mo 85935). Maeda Pt, 1♂, 3.5mm ML, 26° 26′
43.54′′ N, 127° 46′ 20.01′′ E, 26 Jun 2018, coll. J. Jolly and
K. Asada (NSMT-Mo 85934). Onna Pt, 1♂, 5.3mm ML,
26° 40′ 17.90.4′′ N, 127° 50′ 28.78′′ E, 24 Feb 2019, coll.
K. Asada and C. Derup (NSMT-Mo 85933). Sunabe Sea
Wall, 26° 19′ 41.09′′ N, 127° 44′ 35.98′′ E: 1♀, 8.7mm ML
(NSMT-Mo 85936); 1♀, 12.9mm ML (NSMT-Mo 85937);
1♂, 5.7mm ML, (NSMT-Mo 85938); 1♂, 6.4mm ML
(NSMT-Mo 85939); ♂, 6.0mm ML (NSMT-Mo 85940),
24 Feb 2019, coll. B. R. Hannan.
Fig. 7 Kodama jujutsu n. gen.,
n. sp. a dorsal view, male para-
type, 5.3mm ML, NSMT-Mo
85933. b ventral view, specimen
as in a. c funnel, ventral view,
specimen as in b. d funnel-lock-
ing cartilage, paratype female,
12.9mm ML, NSMT-Mo
85937. e mantle-locking carti-
lage, specimen as in d. f, funnel
organ stained with methylene
blue, male paratype, 5.3mm
ML, NSMT-Mo 85933. g
nuchal-locking cartilage, female
paratype 8.7mm ML. Scale
bars: a, b = 1mm, c = 1mm,
d, e = 0.5mm, f = 200µm,
g = 0.5mm
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Other material examined
Sunabe: 2 juv., 26° 19′ 41.09′′ N, 127° 44′ 35.98′′ E, 29 Mar
2019, coll. B. R. Hannan (NSMT-Mo 85941).
Diagnosis
As for genus.
Description
Counts and indices for individual specimens are given in
Tables6 (males) and 7 (females). Only mature specimens
(five males and two females) were measured.
Males smaller than females: ML males 5.3–5.9–6.4mm
(SD 0.4), females 8.7–10.8–12.9mm (SD 3.0). Man-
tle, short, rounded, blunt posteriorly (Fig.7a, b) may
be narrowed, nipple-like in live animals (Fig.11a, c–e,
h); MWI males 64.2–66.2–71.9mm (SD 3.2), females
69.8–71.1–72.4 mm (SD 1.9). Ventral mantle margin
straight to slightly concave (Fig.7b). Fins rounded, maxi-
mum length approximately half mantle length, FLI males
29.7–38.7–43.9mm (SD 5.4), females 48.1–49.9–51.7mm
(SD 2.6); positioned dorso-laterally on posterior third
of mantle, FIIa males 62.3–67.7–78.1 mm (SD 6.1),
females 54.3–59.3–64.4mm (SD 7.1); fin width ~ 30%
ML, FWI males 25.0–29.3–33.3mm (SD 3.3), females
27.6–32.0–36.4mm (SD 6.3); posterior margins curved;
Fig. 8 Kodama jujutsu n. gen.,
n. sp. SEMs female paratype,
12.9mm ML, NSMT-Mo
85937: a arm 1, b arm 1 suck-
ers. c arm 1 enlargement of
sucker rim. d tentacular club.
e tentacular club suckers. f,
g enlargement of club sucker
rim. Scale bars: a = 200µm,
b, e, f = 50µm, c, g = 5µm, d
250µm
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anterior margins with well-developed lobes, lateral lobes
crescentic.
Funnel conical, base broad, tapered anteriorly (Fig.7c);
FuLI males 29.7–38.7–43.9 mm (SD 5.4), females
48.1–49.9–51.7 mm (SD 2.6); free for about 1/5 of its
length, FFuI males 13.2–17.3–21.1mm (SD 2.9), females
17.8–19.3–20.7 mm (SD 2.0). Funnel-locking cartilage
(Fig.7d), strait. Mantle-locking cartilage (Fig.7e) compli-
ments funnel member. Funnel valve small, flaplike, rounded
anteriorly. Funnel organ, dorsal element broad, inverted
V-shape with pointed anterior tip; ventral elements ovoid
(Fig.7f). Nuchal locking-cartilage (Fig.7g) pronounced, deep,
cylindrical, with raised margin of uniform width and median
longitudinal furrow corresponding to rachis of gladius.
Head 40–50% ML, HLI males 46.7–50.7–53.1mm (SD
2.6), females 37.2–38.7–40.2mm (SD 2.1); slightly broader
than ML in both sexes, HWI males 58.3.0–59.8–62.5mm
(SD 1.7), females 48.1–51.0–54.0mm (SD 4.2). Eyes
large, EDI males 11.3–13.9–15.8mm (SD 1.7), females
12.4–13.7–14.9mm (SD 1.8); ventral eyelids free. Eye
covered by corneal membrane. Distinct, large olfactory pit
on latero-posterior surface of head, posterior and ventral
to eyes, close to mantle opening. Posterior-ventral to each
eye is a prominent skin tag positioned ventrolaterally on the
head. Lobes particularly prominent in live animals (Fig.11b,
c, e, g). Slightly anterior to eyes on ventral side of head are a
pair of more prominent, small, rounded whitish projections.
Arms, broad basally, tapered distally, all similar length
(particularly in females); arm formula usually 2.3.1.4 or
3.1.2.4 in males (Table5), arm formula variable in females
(Table 7). Arm length index of longest arm in males
(ALI2) 26.7–37.9–47.2 mm (SD 7.6), females (ALI2)
25.2–32.7–40.2mm (SD 10.6). All arms similar in shape,
U-shaped in section. Sucker pedicels narrow. Chitinous inner
ring of arm suckers without teeth, smooth or slightly crenu-
lated on inner margin (Fig.8a, b). Infundibulum with 4–5
rows of polygonal processes, innermost row of pegs elongate,
cylindrical, with pegs decreasing in size toward outer margin
of sucker, more elongate on one side of the sucker than the
other (Fig.8b); processes expanded, shallow dish-like distally
contain tufts of low lobe-like papillae (Fig.8c), outer-most
sucker rim processes rectangular, tile-like, radially arranged,
smooth, without papillae (Fig.8b). Male and female arm suck-
ers similar in size (Table5). Sucker counts range from 18–25
on male normal arms, 15–24 in females. All arms connected
by relatively shallow webs, protective membranes absent.
Male left ventral arm hectocotylised. Hectocotylus with
8.0–8.6–10.0 (SD 0.9) suckers proximally, remainder of arm
without suckers; distal end of arm with large tongue-like
flap attached dorso-laterally to arm a short distance proxi-
mal to distal arm tip (Fig.9). Right ventral arm unmodified,
with 8.0–8.6–10.0 (SD 0.9) suckers proximally (generally a
greater number of suckers on left than on right ventral arm)
remainder of arm without suckers. Left and right ventral
arms similar in length (Table5).
Tentacles slender, stalks naked, semicircular in sec-
tion; oral surface convex. Club arm-like in form, just
slightly narrower, cylindrical, tapers to blunt end distally
(Fig. 8d); ClLI males 35.2–61.0–83.3 mm (SD 21.4)
females 33.3–37.4–41.4mm (SD 5.7). Sucker-bearing face
of club only slightly convex. Suckers ~ 0.1–0.3mm diam-
eter in centre of club; arranged in two oblique transverse
rows in both sexes. Total number of club suckers in males
24.0–25.6–28.0; females 34.0–34.5–35.0. Club sucker denti-
tion (Fig.3e): inner ring without teeth; infundibulum with
3–4 rows of polygonal processes; pegs narrow, elongate
shallow, cup-like distally bearing papillae in depression.
At periphery, pegs narrower and more elongate, with fewer
papillae (Fig.8f, g). Some inner pegs longer on inner side
and recurved to cover depression. Outer-most sucker rim
processes flattened, rectangular (Fig.3f).
Gills with 15.0–15.4–16.0 (SD 0.5) lamellae per demi-
branch in males; 16.0–17.0–18.0 (SD 1.4) lamellae per
demibranch in females.
Buccal membrane with six lappets and fringed inner mar-
gin; suckers absent. Radula with seven transverse rows of
teeth (Fig.10a). Rachidian teeth, broad rectangular basally,
do not vary in shape along length of radula ribbon; teeth
homodont, without cusps. First lateral teeth much smaller
than rest, triangular, pointed, displaced toward second lat-
erals; second laterals broad-based, much larger in size than
Fig. 9 Kodama jujutsu n. gen, n. sp. hectocotylised left ventral arm
(middle of field) male paratype 5.3mm ML, NSMT-Mo 85933. Scale
bar 5mm
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first laterals and displaced toward midline. Marginal teeth
narrow basally, scythe-like.
Upper beak (Fig.10b) with short, triangular rostrum,
hood curved; lateral margins with row of low teeth. Lower
beak (Fig.10c) with concave, finely toothed rostrum, flanked
laterally by larger conical teeth. Distinct dark pigmentation
restricted to rostrum and hood of upper and lower beaks.
Male reproductive tract (not illustrated) similar in struc-
ture to that of congeners. Spermatophores (Fig.10d) approx-
imately 1/5 mantle length; SpLI 18.3–20.3–22.6mm (SD
2.2). Sperm reservoir simple, without coiled sperm cord.
Cement body bipartite; aboral end elongate, cylindrical, nar-
rows at oral end, connects to sperm reservoir via a narrow
duct, connects via a narrow neck to long, narrower cylin-
drical portion leading to ejaculatory apparatus (Fig.10e).
Oral end of ejaculatory apparatus with 2–3 simple coils
(Fig.10d).
Female reproductive tract: Ovary large, occupies approxi-
mately half of mantle. Eggs of various sizes suggesting
protracted multiple spawning. Ovary opens via single
thick-walled oviduct at anterior end on left side of animal.
Nidamental glands paired, broad, leaf-shaped located ventral
to ovary toward, and overlying anterior half. Accessory nida-
mental glands absent. Eggs ovoid, 0.6–1.5mm diameter;
EgDI 6.9–9.3–11.6mm (SD 3.3).
Gladius a thin, elongate, chitinous structure embedded in
ventral side of dorsal mantle below adhesive pad; extending
full length of mantle. Sclerotised rachis present (Fig.10f).
Preserved animals cream with sparse dark purple chroma-
tophores peppered evenly dorsally and ventrally on mantle,
aboral side of arms and tentacles, and on ventral side of
free portion of funnel. A row of dark chromatophores sur-
rounds distal tip of funnel dorsally and ventrally. Single dark
chromatophore on base of funnel on each side, anterior to
tip of funnel-locking cartilage. Fins with evenly scattered
chromatophores dorsally and ventrally, closest to junction
with mantle. Outer rim of fins devoid of chromatophores.
Chromatophores in a band dorsal to anus and in tissue over-
laying viscera internally and in a patch on each side of anus.
Between dark chromatophores are evenly scattered orange
chromatophores.
Live animals with overall orange to yellow ‘base’ col-
ouration. In some body patterns, chromatophores contract
(appear large) at the same time on the head, in a transverse
Fig. 10 Kodama jujutsu n. gen.,
n. sp. a radula, male, unregis-
tered specimen collected 7 Dec
2019. b upper beak, male para-
type, 6.0mm ML, NSMT-Mo
85940. c lower beak, specimen
as in b. d spermatophore, male
paratype 5.3mm ML, NSMT-
Mo 85933. e enlargement of
oral end of spermatophore,
male paratype 5.7mm ML,
NSMT-Mo 85938. f gladius
(part), unregistered specimen
as in a. Scale bars: a = 20μm;
b, c, f = 1mm; d, e = 0.1mm.
(Note: due to its delicate nature,
the posterior end of the gladius
beyond the rachis was damaged
and lost during staining and
mounting.)
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band toward the anterior end of the mantle and around the
posterior end of the mantle (Fig.10a, d).
Type locality
Japan, Okinawa I, Hamamoto: 1♂, 6.0mm ML, 26° 40′
17.90′′ N, 127° 53′ 17.05′′ E.
Distribution
Japan, Okinawa Island from Miyagi I., 1♀, 6.8mm ML,
26° 22′ N, 127° 59′ E to Sunabe 26° 19′ 41.09′′ N, 127° 44′
35.98′′ E. Visual observations made by Brandon Hannan
(personal communication) extend the northernmost extent
of the range to 26° 30′ 43.02′′ N, 127° 52′ 07.92′′ E. Depth
range 1–20m.
Habitat andbiology
Kodama jujutsu is found around coral reefs and has been
seen hunting and foraging after sunset, often in open water
near reef cuts. Underwater naturalist and photographer,
Shawn Miller, has captured a typical, possibly defence pos-
ture (Fig.10a, c–h) in which the animal spreads the arms and
sometimes the tentacles out widely in a circle surrounding
the mouth, with the distal tips of these appendages curved
inwards. Sometimes the arms are extended dorsally above
the head. This can be accompanied by the contraction of
the mantle posterior to the fins forming a rounded nipple-
like tip. They readily follow shrimp attracted to dive camera
lights or torches at night. The species has also been found in
shallow seagrass beds.
It first attracted Brandon Ryan Hannan’s attention in 2019
when he noticed the unusual protrusions below the eyes and
observed the species attaching itself to the underside of coral
or any underwater substrate. At the popular Sunabe Sea-
wall dive site in Okinawa he observed K. jujutsu attached
to the undersides of various hydroids to which the hydroid
nematocysts (stinging cells) do not deter K. jujutsu. A fur-
ther interesting observation was made in 2019 of the pygmy
squid attached to a hydroid that the swimming nudibranch,
Bornella anguilla S. Johnson, 1984 was eating (Fig.12a).
When the nudibranch reached the end of the hydroid it did
not touch the squid and the squid didn’t move. Clearly the
Fig. 11 Kodama jujutsu n.
gen.,n. sp. a–h, live animals
photographed in the wild. i
laboratory reared hatchling,
dorsal view. j ventral view same
specimen. The large white testis
toward the posterior end of
the mantle is clearly visible in
images c, e and h. Prominent
skin tags posterior to the eyes
can be seen in c, e, g and h, and
the nipple-like posterior tip of
the mantle apparent in some
postures is shown in a, c, and
h. Curling and recurving the
arms appears to be a common
posture. Photos: a, c, d–h, ©
Shawn Miller; b © Brandon
Hannan; i, j © Jeff Jolly
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squid was not concerned about the nudibranch—testament
to the fact that nudibranchs are generally highly specialised
feeders. In this case, the hydroid, and not the pygmy squid is
the target for B. anguilla. (The species is known to extend its
buccal bulb and hydroid branches are drawn into the mouth
to be stripped of its polyps.)
The species has been observed numerous times during
diving around Okinawa at night and sometimes at dusk in
water with temperatures ranging between 20 and 27°C.
When observed eating, the prey was always small shrimp
with bodies smaller or similar in size to themselves (B. Han-
nan, personal observations, Fig.12b, c).
Etymology
The specific name jujutsu is derived from the Japanese word
jūjutsu that is a martial art of the same name, translating to
‘gentle art’. The goal of the sport is to control your oppo-
nents by grappling them. This pygmy squid has been seeing
grappling shrimp in a similar fashion. The name is used as
a noun in apposition.
Remarks
Traits that separate K. jujutsu from X. notoides and Idi-
osepius are described in the generic diagnosis above. The
character combination that separates Kodama jujutsu from
individual Idiosepius spp. are tabulated in Table8.
Some females have spermatophores embedded at the base
of the ventral arm pair. The 3.5mm ML male specimen from
Maeda Point has well-developed spermatophores indicating
this species matures at a very small size.
Behaviour incaptivity
Idiosepius kijimuna and K. jujutsu habitually attach to sub-
strate including aquarium plants and tank walls where they
remain unless swimming to change positions, hunt, or mate.
Both species were observed to attack the dorsal side of prey
to immobilise it within seconds and both swam or attached
to substrate while consuming prey (Online Resource 1,
MOESM1;Fig.5b). Adults of both species swam by pump-
ing water through the funnel and moving the fins in a high
frequency figure-eight motion. Idiosepius kijimuna swam
in sudden and quick movements, sometimes swinging the
mantle in a bobbing motion with the arms recurved or
positioned above the head. The mantle is often inflated,
and rounded and the posterior end is constricted, making
a nipple-like projection (Online Resource 2, MOESM2
and Fig.11). The arms of Kodama jujutsu were usually
splayed outwards and above the head and the tip of the ven-
tral mantle was produced into a nipple. Sometimes while
swimming, the head and arms appeared fixed as the body
moved in a vertical bobbing motion.In this way the out-
line of the animal is disrupted perhaps making it look more
like a bit of floating debris. Idiosepius kijimuna exhibits a
more streamlined and controlled swimming motion (Online
Resources 3MOESM3, 4MOESM4; Fig.5a, c). Prior to
mating, Idiosepius kijimuna males approached females head
on and mating occurred in the head-to-head position (Online
Resource 5,MOESM5). The males appear to deposit the
spermatophores on the oral side of the arm crown, perhaps
in the buccal region. In contrast, Kodama jujutsu males
approached the female from below (i.e., both facing the
same direction) and extended the hectocotylus toward the
female, appearing to deposit spermatophores on the ventral
side of the head (Online Resource 6,MOESM6). Both sexes
Fig. 12 Kodama jujutsu n.
gen., n. sp. a stuck to a hydroid
that is being consumed by the
nudibranch Bornella anguilla.
b side view and c antero-lateral
foreshortened view, capturing
ovigerous caridean shrimp.
Photos: © Brandon Hannan
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exhibited a row of two white papillae posterior-laterally on
either side of the mantle and on the ventral side of the head
when mating and approaching to mate. (While assuming the
hectocotylus in both species was used to deposit spermato-
phores, it is difficult to determine from the video footage
whether the hectocotylus or the tentacles are being used to
place them.) One specimen captured in Okinawa at Miz-
ugama (north wall) laid fertile eggs that successfully hatched
one week after capture. As there were no males present,
clearly the sperm had been stored by the female for at least
one week.
Discussion
Kodama jujutsu is sister to a clade containing X. notoides
and all Idiosepiidae. It shares a number of morphological
traits with the southern Australian endemic species, Xip-
holeptos notoides. Most significantly, both species have a
straight, narrow funnel-mantle locking cartilage and the
gladius extends along the full length of the mantle and has
a distinct medial rachis. The presence of a fully developed
gladius with sclerotised rachis seems to be a primitive trait
in this family that is lost in the genus Idiosepius in which
the gladius is reduced to a chitinous shield. Kodama jujutsu
and X. notoides clearly differ, however, in some other mor-
phological traits, and are clearly separated on molecular
grounds.
The spermatophore transfer method shown by I. kiji-
muna is similar to that of I. thailandicus (Nabhitabhata and
Suwanamala 2008) and differs from I. paradoxus (Ortmann,
1888), where males transfer spermatophores while grasp-
ing females (Sato etal. 2013). The mating behaviour of X.
notoides has not yet been described. Given that K. jujutsu
and X. notoides do not have dimorphic hectocotyli, it may
be that they exhibit similar mating behaviour that differs
from that of Idiosepius spp., with males approaching the
females from below. Observation of the deposition of sper-
matophores in all idiosepiids using high speed photography
as used in Sato etal. (2013) would be valuable to compare
strategies. In addition, it would be useful to re-confirm
whether I. thailandicus Chotiyaputta etal. (1991) uses the
tentacles for spermatophore transfer as reported by Nabh-
itabhata and Suwanamala (2008).
Very apparent from this study is evidence of the impor-
tance of live animal observations in defining taxa within this
family. As these tiny cephalopods are easy to culture in cap-
tivity, and are found at depths readily accessible to divers,
future behavioural studies and observations will undoubtedly
yield many useful insights to aid our understanding of this
particularly enigmatic group of tiny cephalopods.
Appendix
See Table9.
Table 9 Specimens with locality, GenBank voucher information and accession numbers used in this study
Species Sample # Location COI 16S rRNA 12S rRNA
S. patagonica NC_016425 NC_016425 NC_016425
K. n. gen., n. sp. NMST-Mo 85938[1] Japan, Okinawa I., Sunabe Sea Wall LC749837 LC746832 LC746818
K. n. gen., n. sp. NMST-Mo 85940[2] Japan, Okinawa I., Sunabe Sea Wall LC749838 LC746833 LC746819
K. n. gen., n. sp. NMST-Mo 85939[3] Japan, Okinawa I., Sunabe Sea Wall LC749839 LC746834 LC746820
K. n. gen., n. sp. NMST-Mo 85933[4] Japan, Okinawa I., Onna Pt LC749840 LC746835 LC746821
K. n. gen., n. sp. NMST-Mo 85932[5] Japan, Okinawa I., Hamamoto LC749841 LC746936 LC746822
K. n. gen., n. sp. NMST-Mo 85936 [6] Japan, Okinawa I., Sunabe Sea Wall LC749842 LC746837 LC746823
K. n. gen., n. sp. NMST-Mo 85937 [7] Japan, Okinawa I., Sunabe Sea Wall LC749843 LC746838 LC746824
X. notoides WAM S.67769(3) Australia Western Australia MG097850 MG062709 MG062721
X. notoides WAM S.67770(4) Australia, Western Australia MG097851 MG062710 MG062722
X. notoides 38 Australia, Tasmania, Snug EU008975 EF684980 EF680148
X. notoides 39 Australia, Tasmania, Snug EU008976 EF684981 EF680149
X. notoides 40 Australia, Tasmania, Snug EU008977 EF684982 EF680150
X. notoides 41 Australia, Tasmania, Snug EU008978 EF684984 EF680151
I. paradoxus 59 Japan, Ushimado EU008995 EF685003 EF680169
I. paradoxus 55 Japan, Ushimado EU008991 EF684999 EF680165
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Marine Biology (2023) 170:167
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167 Page 24 of 26
Species Sample # Location COI 16S rRNA 12S rRNA
I. paradoxus 61 Japan, Ushimado EU008997 EF684997 EF680171
I. paradoxus 60 Japan, Ushimado EU008996 EF685004 EF680170
I. paradoxus 58 Japan, Ushimado EU008994 EF685002 EF680168
I. paradoxus 57 Japan, Ushimado EU008993 EF685001 EF680167
I. paradoxus 54 Japan, Ushimado EU008990 EF684998 EF680164
I. paradoxus 56 Japan, Ushimado EU008992 EF685000 EF680166
I. paradoxus 53 Japan, Ushimado EU008989 EF684996 EF680163
I. paradoxus 43 Japan, Nagoya EU009065 EF684986 EF680153
I. paradoxus 47 Japan, Nagoya EU008984 EF684990 EF680157
I. hallami AMS C.483477 Australia, S of Tweed Heads MG097849 MG062708 MG062720
I. hallami AMS C.477702 Australia, Bombee Creek MG097842 MG062701 MG062713
I. hallami AMS C.477949 Australia, Lake Illawarra, Warilla* MG097844 MG062703 –
I. hallami AMS C.483437 Australia, Tweed Heads MG097847 MG062706 MG062718
I. hallami 4–2000 Australia, Sydney AY293708 AY293658 AY293634
I. hallami AMS C.477952 Sydney, Port Hacking, Maianbar MG097841 MG062700 MG062712
I. hallami AMS C.479165 Australia, Burrill Lake MG097840 MG062699 MG062711
I. hallami AMS C.269823 Australia, Cudgen Creek MG097845 MG062704 MG062716
I. hallami AMS C.483476 Australia, Pottsville, Mooball Ck MG097848 MG062707 MG062719
I. hallami Australia, Stradbroke I. Dunwich KF647895 KF647895 KF647895
I. hallami C.477703 Australia, Bombee Creek MG097843 MG062702 MG062714
I. hallami C.477930 Australia, Tweed Heads MG097846 MG062705 MG062717
I. pygmaeus 67 Thailand, Lombok I., Ekas Bay EU009003 EF685017 EF680177
I. pygmaeus 66 Thailand, Lombok I., Ekas Bay EU009002 EF685016 EF680176
I. pygmaeus 68 Thailand, Lombok I., Ekas Bay EU009004 EF685018 EF680178
I. pygmaeus 80 Thailand, Phuket I., Klong Mudong, PMBC Pier EU009016 EF685026 EF680190
I. pygmaeus 79 Thailand, Phuket I., Klong Mudong EU009015 EF685025 EF680189
I. pygmaeus 75 Thailand, Phuket I., Klong Mudong EU009010 EF685022 EF680185
I. pygmaeus 72 Thailand, Phuket I., Klong Mudong EU009007 EF685006 EF680182
I. pygmaeus 70 Thailand, Phuket I., Klong Mudong EU009006 EF685020 EF680180
I. pygmaeus 77 Thailand, Phuket I., Klong Mudong EU009013 EF685024 EF680187
I. pygmaeus 63 Thailand, Phuket I., Klong Mudong EU008999 EF685012 EF680173
I. pygmaeus 64 Thailand, Phuket I., Klong Mudong EU009000 EF685013 EF680174
I. pygmaeus 74 Thailand, Phuket I., Klong Mudong EU009009 EF685008 EF680184
I. pygmaeus 78 Thailand, Phuket I., Klong Mudong EU009014 EF685010 EF680188
I. pygmaeus 73 Thailand, Phuket I., Klong Mudong EU009008 EF685007 EF680183
I. pygmaeus 69 Thailand, Phuket I., Klong Mudong EU009005 EF685019 EF680179
I. pygmaeus 76 Thailand, Phuket I., Klong Mudong EU009012 EF685023 EF680186
I. picteti 62 Indonesia, Ambon I
I. paradoxusa50 Japan, Okinawa I EU008986 EF684993 EF680160
I. paradoxusa51 Japan, Okinawa I EU008987 EF684994 EF680161
I. n. sp. AMS C.596046[1] Japan, Okinawa I., Hamamoto LC749830 LC746825 LC746811
I. n. sp. NMST-Mo 85922[2] Japan, Okinawa I., Hamamoto LC746831 LC746826 LC746812
I. n. sp. AMS C.596048[3] Japan, Okinawa I., Hamamoto LC746832 LC746827 LC746813
I. n. sp. AMS C.596049[4] Japan, Okinawa I., Hamamoto LC746833 LC746828 LC746814
I. n. sp. NMST-Mo 85875[5] Japan, Okinawa I. Motobu Hamamoto LC749834 LC746829 LC746815
I. n. sp. NMST-Mo 85878[6] Japan, Okinawa I. Motobu Hamamoto LC749835 LC746830 LC746816
I. n. sp. NMST-Mo 85876[7] Japan, Okinawa I. Motobu Hamamoto LC749836 LC746831 LC746817
I. macrocheirb36 Mozambique, Monque EU008973 EF684978 EF680146
Table 9 (continued)
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Marine Biology (2023) 170:167
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Page 25 of 26 167
Supplementary Information The online version contains supplemen-
tary material available at https:// doi. org/ 10. 1007/ s00227- 023- 04305-1.
Acknowledgements Many thanks to Hiroaki Fukumori who sent AR
specimens of I. kijimuna that were first sequenced and recognised as
an undescribed idiosepiid in Reid and Strugnell (2018). We thank
Keishu Asada for noticing K. jujutsu was likely an undescribed spe-
cies and for his support early in the project via sampling and photog-
raphy. Thanks to Brandon Ryan Hannan, Rob Kidston, Matt Rudolph,
Christian Drerup, and Shawn Miller for their tremendous contributions
photographing and collecting specimens of K. jujutsu. Brandon Hannan
also generously shared some fascinating behavioural observations that
we have included. Thanks to Masahiro Hirano, Zdenik Lajbner, Ryuta
Nakajima, Kaname Sasaki, Chikatoshi Sugmimoto and Ryoko Yanagi-
sawa for collecting specimens of I. kijimuna. Thanks to the molecular
genetics unit at OIST for supporting this project, especially Professor
Daniel Rokhsar for his overall support of the unit, Lin Zhang for her
support in culturing these animals, and Chikatoshi Sugimoto for his
assistance with sampling and knowledge of Okinawan cephalopods. We
thank the Marine Climate Change Unit, particularly Professor Timothy
Ravasi for supporting the project and Yoko Shintani for her logistical
support. We are grateful to Sue Lindsay at Macquarie University, Syd-
ney for assistance with Scanning Electron Microscopy and to Melissa
Joyce for her assistance in preparing Figure1. Finally, many thanks to
the reviewers for their thorough appraisal of this manuscript and very
helpful comments that resulted in its improvement.
Author contributions NS and JJ: led the sample collection, fixed
animals, extracted DNA and sequenced specimens. JS: analysed the
molecular data and generated the phylogenetic tree. JJ: managed the
culture of live animals. AR: wrote the species descriptions and pre-
pared Figs.2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12. All authors contributed to
Table 9 (continued)
Species refer to the names used in GenBank records and associated publications. Names for clades recognised in Reid and Strugnell (2018)
include: a, ‘Okinawa’ n. sp. (and described here as I. kijimuna n. sp.); b, Idiosepius minimus; c, I. thailandicus. Numbers listed under ‘Sample #’
refer to numbers used in Fig.1; corresponding museum specimen registration voucher numbers are included where known
Species Sample # Location COI 16S rRNA 12S rRNA
I. macrocheirb37 Mozambique, Monque EU008974 EF684979 EF680147
I. biserialisb7 Mozambique, Inhambane I EU008947 EF684950 EF680117
I. biserialisb6 Mozambique, Inhaca I EU008946 EF684948 EF680116
I. biserialisb3 Mozambique, Inhaca I EU008943 EF684945 EF680113
I. biserialisb4 Mozambique, Inhaca I EU008944 EF684946 EF680114
I. biserialisb5 Mozambique, Inhaca I EU008945 EF684947 EF680115
I. biserialisb12 Mozambique, Inhambane I EU008952 EF684955 EF680122
I. biserialisb17 Mozambique, Monque EU008956 EF684959 EF680127
I. biserialisb11 Mozambique, Inhambane I EU008951 EF684954 EF680121
I. biserialisb10 Mozambique, Inhambane I EU008950 EF684953 EF680120
I. biserialisb8 Mozambique, Inhambane I EU008948 EF684951 EF680118
I. biserialisb9 Mozambique, Inhambane I EU008949 EF684952 EF680119
I. biserialisc34 Thailand, Ko Pratong, Type: Hylleberg PMB7957 EU008971 EF684976 EF680144
I. biserialisc22 Thailand, Phuket I., Klong Bangrong EU008959 EF684964 EF680132
I. biserialisc27 Thailand, Phuket I., Klong Bangrong EU008964 EF684969 EF680137
I. biserialisc24 Thailand, Phuket I., Klong Bangrong EU008961 EF684966 EF680134
I. thailandicusc82 Thailand, Rayong Province, Chantaburi Ban Phe EU009018 EF685028 EF680192
I. thailandicusc83 Thailand, Rayong Province, Chantaburi Ban Phe EU009020 EF685029 EF680193
I. thailandicusc84 Thailand, Rayong Province, Chantaburi Ban Phe EU009020 EF685030 EF680194
I. thailandicusc86 Thailand, Rayong Province, Chantaburi Ban Phe EU009022 EF685032 EF680196
I. thailandicusc81 Thailand, Rayong Province, Chantaburi Ban Phe EU009017 EF685027 EF680191
I. thailandicusc85 Thailand, Rayong Province, Chantaburi Ban Phe EU009021 EF685031 EF680195
I. biserialisc2 Indonesia, Lombok I., Ekas Bay EU008942 EF684944 EF680112
I. biserialisc1 Indonesia, Lombok I., Ekas Bay EU008941 EF684943 EF680111
I. biserialisc23 Thailand, Phuket I., Klong Bangrong EU008960 EF684965 EF680133
I. biserialisc20 Thailand, Phuket I., Klong Bangrong EU008958 EF684962 EF680130
I. biserialisc25 Thailand, Phuket I., Klong Bangrong EU008962 EF684967 EF680135
I. biserialisc26 Thailand, Phuket I., Klong Bangrong EU008963 EF684968 EF680136
I. biserialisc31 Thailand, Phuket I., Klong Bangrong EU008968 EF684973 EF680141
I. biserialisc30 Thailand, Phuket I., Klong Bangrong EU008967 EF684972 EF680140
I. biserialisc29 Thailand, Phuket I., Klong Bangrong EU008966 EF684971 EF680139
I. biserialisc28 Thailand, Phuket I., Klong Bangrong EU008965 EF684970 EF680138
I. biserialis 32 Thailand, Phuket I., Klong Bangrong EU008969 EF684974 EF680142
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Marine Biology (2023) 170:167
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167 Page 26 of 26
the writing and the final editing of the manuscript. All authors read and
approved the final manuscript.
Funding Open Access funding enabled and organized by CAUL and
its Member Institutions. Funding for this project was provided by the
Okinawa Institute of Science and Technology (OIST) to the Molecular
Genetics and the Marine Climate Change Units.
Data/code availability Genetic sequence data are available from Gen-
Bank, https:// www. ncbi. nim. nih. gov/ genba nk/.
Declarations
Conflict of interest The authors have no conflicts of interest to declare
that are relevant to the content of this article.
Ethical approval Cephalopods are not covered under the Japanese
legislation ‘Act on Humane Treatment and Management of Animals’
(Ogden etal. 2016). Procedures and rearing protocols followed the
guidelines set by Directive 2010/63/EU for cephalopods (Fiorito etal.
2015) and animal welfare guidelines set by OIST Animal Care and
Use Committee. The highest quality of care was taken to reduce the
suffering of animals.
Open Access This article is licensed under a Creative Commons Attri-
bution 4.0 International License, which permits use, sharing, adapta-
tion, distribution and reproduction in any medium or format, as long
as you give appropriate credit to the original author(s) and the source,
provide a link to the Creative Commons licence, and indicate if changes
were made. The images or other third party material in this article are
included in the article’s Creative Commons licence, unless indicated
otherwise in a credit line to the material. If material is not included in
the article’s Creative Commons licence and your intended use is not
permitted by statutory regulation or exceeds the permitted use, you will
need to obtain permission directly from the copyright holder. To view a
copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
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