Distribution and systematics of the cosmopolitan Amynthas carnosus complex (Crassiclitellata, Megascolecidae) from eastern AsiaAuthorHan, Anne Charis N.State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China & Hebei Key Laboratory of Animal Diversity, College of Life Science, Langfang Normal University, Langfang 065000, ChinaAuthorZhang, Yufeng0000-0002-4066-6355Hebei Key Laboratory of Animal Diversity, College of Life Science, Langfang Normal University, Langfang 065000, ChinaAuthorMiao, PuHenan Province Tobacco Company, Luoyang 471000, ChinaAuthorWu, ShaolongHunan Province Tobacco Company, Changsha 410004, ChinaAuthorXiao, NengwenState Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, ChinaAuthorQin, MingyanState Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China & Hebei Key Laboratory of Animal Diversity, College of Life Science, Langfang Normal University, Langfang 065000, ChinaAuthorZhao, Huifeng0000-0003-4243-9671Hebei Key Laboratory of Animal Diversity, College of Life Science, Langfang Normal University, Langfang 065000, China & Key Laboratory of Wetland Ecology and Environment, State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, ChinaAuthorWu, DonghuiState Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China & Key Laboratory of Wetland Ecology and Environment, State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, ChinaAuthorAspe, Nonillon M.0000-0003-0025-6017College of Marine and Allied Sciences, Mindanao State University at Naawan, Naawan 9023, Misamis Oriental, PhilippinestextZoosystematics and Evolution20242024-08-01100310611073journal article30042510.3897/zse.100.119292bd93a5c6-9029-4630-8554-7af18882cab2541660A7-7B6A-4432-AEF5-C689737C0A3CAmynthas carnosus carnosusGoto & Hatai, 1899Perichaeta carnosa
Goto & Haitai, 1899: 15
.
Pheretima carnosa
–
Kobayashi 1936: 115
.
Amynthas carnosus
–
Sims and Easton 1972: 235
.
Blakemore 2012: 36
;
2013 a
: 58
;
2013 c
: 101
.
Carrera-Martínez and Snyder 2016: 297
.
Chang et al. 2016: 505
.
Amynthas pingi
(
Stephenson, 1925
) –
Sims and Easton 1972: 235
.
Blakemore 2013 c
: 112
.
Material examined.
Specimen IDs: 362
R
1 _ 01, 02, 04, 05, 06, 07, 09, seven matures from Nanshan Park, Jinzhou,
Liaoning
; 533
R
70 _ 08, 09, 10, three matures from Jinjiang Mt. Park, Dandong,
Liaoning
;
LFXHR
7 _ 02, 04, 05, three matures from Zhuti Park, Xianghe County, Langfang,
Hebei
;
LFSF
_ 013, one mature from Langfang Normal University, Anci District Langfang,
Hebei
; E 29 _ 05, one mature from an anonymous park in Dongli District,
Tianjin
Municipality;
HNLNR
2 _ 04, 05, 06, three matures from the tobacco field in Xiaojie Town, Luoning County, Luoyang,
Henan
;
HNSQ
_ 07, 13, 15, three matures under the bushes in Shangqiu Normal University, Liangyuan District, Shangqiu,
Henan
.
Diagnosis.
Length
105–210 mm
. Spermathecal pores having four pairs in 5 / 6 / 7 / 8 / 9, rarely 3 pairs in 6 / 7 / 8 / 9, with pre-intersegmental hemispherical arc (spermathecal papillae). Dorsal pores typically from 12 / 13. Pre-clitellar genital markings typically with two pairs, pre-setal in
VIII
and
IX
; these genital markings paired either widely or closely apart (B 1 and B 2, Fig.
3
); Post-clitellar genital markings prominent, up to three pairs median to male pores; first pair pre-setal on XVIII, slightly median to male pores; second pair post-setal and more medial than the first; third pair pre-setal in XIX (Fig.
4
). Male pores superficially paired in XVIII close to the lateral margin on round or elliptical porophores (Fig.
4
). Ampulla ovate to narrowly ovate (Fig.
2 D-F
). Intestinal caeca simple at XXVII.
Amynthas carnosus carnosus
variations on the number of spermathecal pores and spermathecae: four pairs (
A, D
) (specimen ID 362 R 1 _ 06), three pairs (
B, E
) (specimen ID LFXHR 7 _ 05), five pairs (
C, F
) (specimen ID HNLNR 2 _ 05). Scale bars: 1 mm.
Pre-clitellar genital marking (arrows) variations of
Amynthas carnosus
.
A.
Modified fig. 1 of the variations of pre-clitellar genital markings from
Kobayashi (1936)
;
B.
This study.
B 1.
(specimen ID 362 R 1 _ 01);
B 2.
(specimen ID 533 R 70 _ 09), and
B 3.
(specimen ID HNLNR 2 _ 05) comply with the “ permissible variations ” [termed by
Blakemore (2012)
] of
Kobayashi’s (1936)
Type III (red), VI (blue), and VIII (green).
Post-clitellar genital marking (arrows) variations of
Amynthas carnosus
.
A.
Modified fig. 2 of the variations of post-clitellar genital markings from
Kobayashi (1936)
;
B.
This study.
B 1, B 2.
(specimen IDs 362 R 1 _ 07 and HNLNR 2 _ 04);
B 3
(specimen ID 362 R 1 _ 04);
B 4, B 5.
(specimen IDs 362 R 1 _ 01 and 533 R 70 _ 10) comply with the “ permissible variations ” [termed by
Blakemore (2012)
] of
Kobayashi’s (1936)
Type II (red), IV (blue), and V (green).
Variations.
For the
A. c.
carnosus
from
China
, the number of spermathecal pores and spermathecae are variable: 14 out of
16 specimens
typically have four pairs in 5 / 6 / 7 / 8 / 9,
one specimen
has three pairs in 6 / 7 / 8 / 9 (
LFXHR
7 _ 05), and another one has five pairs in 4 / 5 / 6 / 7 / 8 / 9 (
HNLNR
2 _ 05) (Fig.
2
). However, despite these variations, molecular analyses have shown them to belong in the same clade with little genetic divergence within the clade (Table
2
, Fig.
1
).
Two specimens
from
South Korea
and
one specimen
from the
USA
have three pairs of spermathecal pores in 6 / 7 / 8 / 9 (
Kobayashi 1936
;
Carrera-Martínez and Snyder 2016
). However, prior to this study, no other specimen with five pairs was recorded elsewhere.
Distribution.China
(
Liaoning
,
Beijing
,
Tianjin
,
Hebei
,
Henan
, and
Shanghai
),
Japan
(Kyushu, Honshu, and
Hokkaido
), and
South Korea
(
Incheon
,
Jeju
Island).
Remarks.
Detailed descriptions of
A. carnosus
were reported by
Kobayashi (1936)
,
Ohfuchi (1937)
, and
Blakemore (2012
,
2013 a
,
c
). Rather than typical closely spaced mid-ventral pre-clitellar genital markings (
Blakemore 2012
), widely spaced ones are mostly observed with the
A. carnosus
specimen from
China
, which resembles those Hikone specimens from
Japan
(
Tokyo
An- 460 - DNA JET- 112) [cf. fig. 3 by
Blakemore (2013 a
)]. In contrast, the closely spaced pre-clitellar genital markings of the Liaoning specimens (Dandong, DNA 533
R
) match those of the South Korean specimen from Geoman (
NIBRIV
261234 - DNA w 37) and the Japanese
neotype
of
A. carnosus
(
Tokyo
An 435) [cf. fig. 2 by
Blakemore (2013 a
)].
A comparison of characters from the specimens of
China
,
Japan
(a
neotypeNSMT
An 435 from the
Tokyo
Museum) (
Blakemore 2012
), and the
USA
(
Kansas
) (
Chang et al. 2016
) is presented in Suppl. material
1
: table S 2. External characters such as the number of spermathecal pores and segment locations of pre-clitellar genital markings match among specimens from different countries. However, internal character variations are observed in the position of the intestinal caeca, which was reported to begin at XXVII and extend to XXIII or XXIV (
Blakemore, 2012
; 2013 b; 2013 c;
Chang et al. 2016
), while the intestinal caeca in the Chinese specimens extends up to XX, XXI (or
XXIII
) (Fig.
5
), 2–3 segments more anterior than those from the two previous accounts. Moreover, some character measurements that were not presented in the other two accounts, such as the ventral distances between male pores (
0.25–0.29 mm
), spermathecal pores (
0.28–0.30 mm
), and genital markings (latero-ventrally with
0.21–0.29 mm
distance apart or mid-ventrally with
0.08 mm
distance apart), were added to further aid species identification.
Amynthas carnosus carnosus
intestinal caeca showing the segment length variations:
A.
(specimen ID 533 R 70 _ 10);
B.
(specimen ID 362 R 1 _ 05), and
C.
(specimen ID HNLNR 2 _ 05). Scale bars: 1 mm.
Kobayashi (1936)
, in his thorough investigation of
A. carnosus
, presented “ permissible ” variations on the pre-clitellar and post-clitellar genital markings [text-figs.
1–2 inKobayashi (1936)
]. The pre-clitellar genital making variations in the
A. c.
carnosus
from
China
comply with Kobayashi’s Types
IIII
,
VI
, and
VIII
(see Fig.
3
), while the post-clitellar genital marking variations comply with Kobayashi’s Types
II
,
IV
, and
V
(see Fig.
4
). It is important to take note that genital marking patterns can also be considered a distinctive character for species identification (e. g.,
Nguyen et al. 2020
;
Aspe et al. 2021
).