First record of Orobdellakawakatsuorum (Hirudinida: Arhynchobdellida: Erpobdelliformes) from Kunashir Island, Kuril Islands
Author
Nakano, Takafumi
Author
Gongalsky, Konstantin B.
text
Biodiversity Data Journal
2014
2
1058
1058
http://dx.doi.org/10.3897/BDJ.2.e1058
journal article
http://dx.doi.org/10.3897/BDJ.2.e1058
1314-2828--1058
Orobdella kawakatsuorum Richardson, 1975
Materials
Type status:
Other material
. Occurrence: catalogNumber:
KUZ Z675
; individualCount:
1
; sex:
hermaphrodite
; Location: island: Kunashir Island; verbatimLocality: near Ivanovsky cordon of Kurilsky Nature Reserve, 600 m from the Sea of Okhotsk, Kunashir Island; decimalLatitude:
43.839933N
; decimalLongitude:
145.412833E
; Identification: identifiedBy:
Takafumi Nakano
; Event: eventDate:
2012-08-23
; habitat: Oak (Quercuscrispula) forest with bamboo (Sasa sp.) and lianas (Hydrangeapaniculata, Vitiscoignetiae), forest canopy density 60%, grass cover density 100%, litter depth up to 15 cm; Record Level: institutionCode:
KUZ
Type status:
Other material
. Occurrence: catalogNumber:
KUZ Z676
; individualCount:
1
; sex:
hermaphrodite
; Location: island: Kunashir Island; verbatimLocality: near Ozernyi cordon of Kurilsky Nature Reserver, on the eastern slope of Golovnin Volcano caldera, 1 km from the Sea of Okhotsk, Kunashir Island; decimalLatitude:
43.875333N
; decimalLongitude:
145.476617E
; Identification: identifiedBy:
Takafumi Nakano
; Event: eventDate:
2012-08-26
; habitat: Fir (Abiessachalinensis) forest with birch (Betulaplatyphylla) and oak (Quercuscrispula) and bamboo (Sasa sp.), forest canopy density 70%, grass cover density 80%; Record Level: institutionCode:
KUZ
Description
Body firm, muscular, elongated, with constant width in caudal direction, dorsoventrally compressed, BL 23.8-32.5 mm, BW 3.7-4.9 mm (Fig. 2). Caudal sucker elliptic, minor axis 1.0-1.6 mm, major axis 1.9-2.7 mm (Fig. 2b). Somite I completely merged with prostomium. Somites II, III uniannulate. Somites IV, V biannulate. Somites VI, VII triannulate. Somites
VIII-XXV
quadrannulate (Fig. 3a). Somite XXVI triannulate. Somite XXVII uniannulate; anus behind it. Eyes in 3 pairs, first pair dorsally on posterior margin of II, second and third pairs dorsolaterally on posterior margin of V (a1 + a2). Nephridiopores in 17 pairs, 1 each situated ventrally at posterior margin of a1 of each somites in
VIII-XXIV
(Fig. 3a).
Pharynx reaching to XIV b5/b6 (Fig. 3b). Crop reaching to XX b5-XX/XXI (Fig. 3b). Gastropore in furrow of XIII a1/a2 (Fig. 3a, c). Gastroporal duct tubular, joining with crop in XIV b5/b6 (Fig. 3b). Intestine reaching to XXV a1/a2-b5/b6. Rectum descending to anus.
Male gonopore at anterior margin of XI b6 (Fig. 3a). Female gonopore in furrow of XIII a1/a2 (Fig. 3c). Gonopores separated by 6 annuli (Fig. 3a). Testisacs undeveloped, undetectable. Paired epididymides in XVI b5/b6-XVII a1/a2, occupying 2 annuli (Fig. 3d). Ejaculatory ducts in XI b5 to XVI b5/b6, nearly straight. Atrial cornua undeveloped. Atrium globular, in XI b6. Paired ovisacs globular, 1 each in XIII a2 and b5. Oviducts short, both oviducts converging into common oviduct in XIII a2. Common oviduct directly descending to female gonopore.
Distribution
Orobdella kawakatsuorum
is distributed in Hokkaido, Japan, and its peripheral islands and inhabited in mountainous regions of these islands (
Nakano 2012a
). The present specimens have extended the known distributional range of the species north to include the southern tip of the Kuril Islands.
Genetic data
The obtained neighbor-joining tree (Fig. 4) showed that two
Orobdella
specimens from Kunashir Island (KUZ Z675, Z676) formed a monophyletic lineage with the individual of
Orobdella kawakatsuorum
from Shiretoko, Hokkaido (KUZ Z152). No difference between the
tRNALeu-ND
1 sequences from the Kunashir specimens. The K2P distance was detected between these two specimens (KUZ Z675, Z676) and that from Shiretoko (KUZ Z152) was 0.5%.
Taxon discussion
Two specimens of
Orobdella
from Kunashir Island clearly belong to
Orobdella kawakatsuorum
based on the following characteristics: male gonopore in the anterior margin of XI b6, female gonopore in the furrow of XIII a1/a2, 6 annuli between gonopores, and epididymides occupying 2 annuli. According to
Nakano (2012a)
,
Orobdella kawakatsuorum
grows to ca. 10 cm length. However, the body length of the Kunashir specimens is only ca. 3 cm. Since they have undeveloped male atria and undetectable testisacs, they were considered immature individuals. As noted in the Introduction, two quadrannulate species of
Orobdella
,
Orobdella kawakatsuorum
and
Orobdella koikei
, are distributed in Hokkaido.
Orobdella koikei
is the closest congener of
Orobdella kawakatsuorum
according to the recent molecular phylogenetic study and the smallest species among the known species of
Orobdella
(
Nakano 2012a
). The body length of the known mature leeches of
Orobdella koikei
is less than 4 cm. Therefore, based only on their body length, a possibility exists that the Kunashir specimens might be misidentified as
Orobdella koikei
. However,
Orobdella kawakatsuorum
, as well as the present specimens, are clearly distinguished from
Orobdella koikei
in the characteristics mentioned above: the latter possesses 1/2 + 4 + 1/2 annuli between gonopores (male gonopore in the middle of XI b6, female gonopore in the middle of XIII a1), and the epididymides occupy 9-12 annuli. Our
tRNALeu-ND
1 data provided additional confirmation that the
Orobdella
leeches from Kunashir Island were identified correctly as
Orobdella kawakatsuorum
.
Orobdella kawakatsuorum
was collected from Rishirito Island (
Nakano 2012a
), which is located ca. 20 km away from Hokkaido (Fig. 1). Additionally, Kunashir Island lies offshore of Hokkaido. Thus, anticipating that
Orobdella
leeches might occur on the island was not difficult. Our findings suggest that
Orobdella
species may also be present in the southern part of the Kuril Islands, e.g., Iturup Island and Shikotan Island. Further faunal surveys should be conducted not only in the South Kurils, but also in the northern part of the Kuril Islands, as well as the Kamchatka Peninsula, to fully reveal the northern distributional limit of the genus
Orobdella
.