Two new species of the genus Symphylella (Symphyla, Scolopendrellidae) from China and the significance of the frons chaetotaxy
Author
Jin, Ya-Li
Natural History Research Center, Shanghai Natural History Museum, Shanghai Science & Technology Museum, Shanghai, 200041, China
Author
Bu, Yun
https://orcid.org/0000-0002-7177-9686
Natural History Research Center, Shanghai Natural History Museum, Shanghai Science & Technology Museum, Shanghai, 200041, China
buy@sstm.org.cn
text
ZooKeys
2023
2023-01-05
1138
143
160
http://dx.doi.org/10.3897/zookeys.1138.96424
journal article
http://dx.doi.org/10.3897/zookeys.1138.96424
1313-2970-1138-143
B3E1F9F6368F476F9A03E2C35736BBFD
F274E9EAD22F51458ACB56030A1392BA
Symphylella macrochaeta Jin & Bu
sp. nov.
Figs 1
, 2
, 3
Diagnosis.
Symphylella macrochaeta
sp. nov. is characterized by 10 extremely long macrosetae arranged as 4/4/2 on the frons, 4+4 setae on the first tergite and broad triangular processes on tergites.
Material examined.
Holotype
: female (slide no. ZJ-ZS-SY2020029) (SNHM),
China
,
Zhejiang Province
,
Zhoushan City
,
Changgang
Mountain Forest Park
, extracted from soil samples of broad-leaf forest, alt.
250 m
,
30°2'N
,
121°7'E
,
17-XI-2020
, coll.
Y. L. Jin
et al.
Paratypes
:
10 females
(slides no. ZJ-ZS-SY2020006, ZJ-ZS-SY2020008, ZJ-ZS-SY2020014-ZJ-ZS-SY2020016, ZJ-ZS-SY2020024-ZJ-ZS-SY2020028) (SNHM), same data as holotype
.
2 females
(slides no. SH-JZGY-SY2017032, SH-JZGY-SY2017034),
China
,
Shanghai
,
Jiuzi Park
, extracted from soil and litter samples of bamboo forest, alt.
14 m
,
31°15'N
,
121°28'E
,
25-V-2017
, coll.
Y. L. Jin.
Non-type specimens
:
18 juveniles
with 7-10 pairs of legs, same data as holotype
;
5 juveniles
with 9 or 10 pairs of legs,
China
,
Shanghai
,
Jiuzi Park
, extracted from soil and litter samples of bamboo forest, alt.
14 m
,
31°15'N
,
121°28'E
,
25-V-2017
, coll.
Y. L. Jin
;
1 juvenile
with 10 pairs of legs,
China
,
Shanghai
,
Tianma Mountain
, extracted from soil samples of bamboo forest, alt.
98 m
,
31°5'N
,
121°9'E
,
10-V-2017
, coll.
Y. Bu.
Description.
Adult body 2.1 mm long in average (1.9-2.2 mm,
n
= 11), holotype 2.1 mm (Fig.
1A
).
Head
length 250-280
μm
, width 223-265
μm
, with widest part on equal level of points of articulation of mandibles. Central rod distinct in both anterior (65-70
μm
) and posterior (75-85
μm
) parts, with an obvious middle node-like interruption. Head dorsally covered with setae of different lengths (Fig.
1B
). Frons with 5+5 lateral setae, 10 extremely long macrosetae (58-73
μm
) arranged as 4/4/2 (counted from anterior row to posterior row) and 4-5.6 times as long as antero-central seta (a0) (Fig.
3H
), and 20-21 short to medium-length setae (8-16
μm
) (Figs
1B
,
3H
). Cuticle on anterolateral part of head with coarse granules (Fig.
1B
).
Figure 1.
Symphylella macrochaeta
sp. nov.
A
habitus, dorsal view
B
head, anterior part, dorsal view
C
tergites 1-3
D
tergites 13-14
E
Toemoesvary
organ
F
first pair of legs (arrows indicate reduced legs)
G
tergite 1
H
styli and coxal sacs on base of leg 3 (arrows indicate styli).
I
cerci, dorsal view
J
left cercus, ventral view (arrows indicate long and erect outer setae). Scale bars: 100
μm
(
A
); 20
μm
(
B-J
).
Toemoesvary
organ
globular, diameter 15-20
μm
, about half of greatest diameter of third antennomere (35-40
μm
), opening round (9-12
μm
), inner margins of opening covered with regular vertical striae (Fig.
1E
).
Mouthparts
.
Mandible composed by pars incisivus (
pi
) and pars molaris (
pm
), with movable appendage lacinia mobilis (
lm
) inserted between them. Pars incisivus with 4 distinct thick teeth, pars molaris with 4 smaller teeth and 2 proximal spines, and lacinia mobilis with only 1 blunt process observed from lateral view (Fig.
3A
). First maxilla has 2 lobes, inner lobe with 6 hook-shaped teeth and pubescent apically, palp pointed (Fig.
3B
). Anterior part of second maxilla with many small protuberances, each carrying 1 seta, distal setae thicker and spiniform; posterior part with sparse setae. Cuticle of second maxilla covered with dense pubescence.
Antennae
with 16-20 antennomeres (18 in holotype), about 0.2 of body length. First antennomere cylindrical, length about 0.5-0.8 of greatest diameter (width 33-40
μm
, length 18-25
μm
), with 6 or 7 setae in 1 whorl, longest inner seta 16-18
μm
(Fig.
3C
). Second antennomere wider (35-38
μm
) than long (27-33
μm
), with 8 setae evenly inserted around antennal wall with interior setae (15
μm
) slightly longer than exterior ones (11
μm
) (Fig.
3C
). Chaetotaxy of third antennomere similar to preceding ones. Setae on proximal antennomeres longer and on distal antennomeres shorter. Proximal antennomeres with only primary whorl of setae (Fig.
3C
). Secondary whorl appearing ventrally on antennomeres 6-8. Four kinds of sensory organs observed on antenna: rudimentary spined sensory organs (
rso
) on dorsal side of most antennomeres (Fig.
3C, D
); spined sensory organs (
so
) with more surrounding spines and larger than
rso
, only present on apical antennomere (Fig.
3D, E
); cavity-shaped organs (
co
) on antennomeres 6 and 7 next to subapical one (Fig.
3D
); bladder-shaped organs (
bo
) on antennomeres 9-11 next to subapical one increasing in number on subdistal antennomeres to 15 in maximum (Fig.
3D, E
). Apical antennomere subspherical, with its length as long as width (28-30
μm
), with 5 spined sensory organs consisting of 3 or 4 curved spines around a central pillar and 12-16 setae located distally (Fig.
3D, E
). All antennomeres covered with short pubescence. Chaetotaxy and sensory organs on antennae of holotype are given in Table
1
.
Table 1.
Numbers of setae and sensory organs on antennae of
Symphylella macrochaeta
sp. nov. (holotype).
| Antennomere |
Primary whorl setae |
Secondary whorl setae |
Rudimentary spined sensory organs |
Cavity-shaped organs on dorsal side |
Bladder-shaped organs |
| 1 |
6 |
- |
1 |
- |
- |
| 2 |
8 |
1 |
| 3 |
8 |
1 |
| 4 |
9 |
1 |
| 5 |
9 |
1 |
| 6 |
11 |
1 |
1 |
| 7 |
11 |
2 |
1 |
1 |
| 8 |
11 |
2 |
0 |
1 |
| 9 |
10 |
3 |
0 |
1 |
| 10 |
11 |
3 |
1 |
1 |
1 |
| 11 |
11 |
4 |
1 |
1 |
1 |
| 12 |
11 |
5 |
1 |
1 |
1 |
| 13 |
11 |
6 |
1 |
1 |
2 |
| 14 |
11 |
6 |
0 |
1 |
3 |
| 15 |
10 |
7 |
0 |
1 |
3 |
| 16 |
10 |
6 |
- |
3 |
5 |
| 17 |
10 |
6 |
3 |
8 |
Trunk
with 17 tergites. Tergites 2-13, and 15 each with 1 pair of triangular processes. Length from base to tip of processes somewhat shorter than or same as its basal width; basal distance between processes longer than their length from base to tip except on tergites 2 and 3 (Table
3
). All processes with roundish swollen ends (Figs
1C
,
2A-D
). Definition of chaetotaxy on tergite as follow: anterolateral setae (
als
) located on anterolateral angle of each tergite; apical seta (
as
) most close to process apex; lateromarginl setae (
lms
) located on lateral margin of process and including
als
and
as
; inner basal setae (
ibs
) located on inner base of process; inserted setae (
is
) present between
ibs
and
as
; central setae (
cs
) present between base of processes; other setae including all setae except above nominated ones (Fig.
2A
). Anterolateral setae of tergites 2, 3, 5, 6, 8, 9 11 and 12 slightly shorter than length of process of same tergite, that of tergites 4, 7, 10, 13 and 15 subequal or slightly longer than length of process of same tergite. Processes with 1 or 2 inserted setae. All tergites pubescent (Fig.
2A-D
).
Figure 2.
Symphylella macrochaeta
sp. nov.
A
tergite 2 (
als
- anterolateral seta,
lms
- lateromarginl setae,
as
- apical seta,
is
- inserted seta,
ibs
- inner basal seta,
cs
- central seta)
B
tergite 3
C
tergite 4, left side
D
tergite 5, left side. Scale bars: 20
μm
.
Figure 3.
Symphylella macrochaeta
sp. nov.
A
mandible, lateral view (
pi
- pars incisivus,
pm
- pars molaris,
lm
- lacinia mobilis)
B
first maxilla
C
left 1-3 antennomere, dorsal view
D
terminal three antennomeres, dorsal view (
bo
- bladder-shaped organ,
co
- cavity-shaped organ,
rso
- rudimentary spined sensory organ,
so
- spined sensory organ)
E
terminal three antennomeres, ventral view
F
left cercus, dorsal view (arrows indicate long and erect outer setae)
G
left cercus, ventral view
H
frons (L1-L5 - lateral setae, a0 - antero-central seta, arrows indicate macrosetae)
I
leg12, dorso-lateral view. Scale bars: 20
μm
.
Tergites
.
Tergite 1 reduced, with 4+4 setae of different length (Fig.
1G
). Tergite 2 complete, with 2 broad triangular posterior processes, 6 or 7 lateromarginal setae, 1 or 2 inserted setae, 1 or 2 central setae (Table
2
), with anterolateral setae 0.8-0.9 time as long as length of process, length of processes 0.8-1.0 time as long as broad, basal distance between processes 0.6-0.9 time as long as their length (Figs
1C
,
2A
). Tergite 3 complete, broader and longer than preceding one, with ratios of 0.7-0.9, 0.8-1.0, and 0.6-0.9 respectively, 8-10 lateromarginal setae, 1 or 2 inserted setae, 1-3 central setae (Figs
1C
,
2B
). Tergite 4 broader than tergite 3, with ratios 1-1.3, 0.6-0.7, and 1.3-2.5 respectively, 5-7 lateromarginal setae (Fig.
2C
). Chaetotaxy of tergites 5-7, 8-10, and 11-13 similar as tergites 2-4 (Fig.
2D
). Pattern of alternating tergite lengths of 2 short-tergites followed by long-tergite only disrupted at caudal end (Table
3
). Tergites 14 and 16 without processes and with 17-26 and 12-17 setae respectively (Fig.
1D
). Tergite 17 with 27-38 setae. Chaetotaxy and measurements of tergites are given in Tables
2
and
3
.
Table 2.
Chaetotaxy of tergites of
Symphylella macrochaeta
sp. nov. (holotype in brackets).
| Tergite |
Lateromarginal setae |
Inserted setae |
Central setae |
Other setae |
| 1 |
4+4 |
| 2 |
6-7 (6) |
1-2 (2) |
1-2 (2) |
6-10 (6) |
| 3 |
8-10 (8) |
1-2 (2) |
1-3 (2) |
14-25 (14) |
| 4 |
5-7 (6) |
1-2 (1) |
3-5 (3) |
10-15 (11) |
| 5 |
5-7 (6) |
1-2 (2) |
2-4 (3) |
7-13 (12) |
| 6 |
8-10 (9) |
1-2 (2) |
2-4 (4) |
17-28 (20) |
| 7 |
5-7 (6) |
1-2 (2) |
4-6 (4) |
10-14 (11) |
| 8 |
5-7 (6) |
1-3 (2) |
3-5 (4) |
10-14 (10) |
| 9 |
8-10 (9) |
1-3 (1) |
3-5 (3) |
20-27 (22) |
| 10 |
5-6 (6) |
1-2 (1) |
4-6 (4) |
9-14 (11) |
| 11 |
5-8 (6) |
1-2 (1) |
3-5 (4) |
7-14 (9) |
| 12 |
7-10 (8) |
1-2 (2) |
3-5 (3) |
15-24 (15) |
| 13 |
4-7 (5) |
0-2 (1) |
2-5 (3) |
8-14 (8) |
| 14 |
- |
17-26 (21) |
| 15 |
6-9 (7) |
0/2 (0) |
2-4 (3) |
14-19 (14) |
| 16 |
- |
12-17 (14) |
| 17 |
- |
27-38 (29) |
Table 3.
Measurements of tergites and processes of
Symphylella macrochaeta
sp. nov. (mean
+/-
se,
n
= 11, in
μm
) (holotype in brackets).
| Tergite |
Length |
Width |
Length of processes |
Basal width of processes |
Basal distance between processes |
| 1 |
24
+/-
7 (23)
|
141
+/-
13 (138)
|
- |
| 2 |
48
+/-
5 (45)
|
144
+/-
7 (150)
|
37
+/-
3 (33)
|
41
+/-
3 (43)
|
28
+/-
4 (32)
|
| 3 |
102
+/-
14 (100)
|
186
+/-
25 (180)
|
41
+/-
4 (42)
|
45
+/-
3 (47)
|
33
+/-
3 (37)
|
| 4 |
57
+/-
7 (55)
|
194
+/-
17 (205)
|
33
+/-
3 (35)
|
49
+/-
5 (52)
|
60
+/-
8 (65)
|
| 5 |
71
+/-
12 (65)
|
183
+/-
10 (190)
|
41
+/-
5 (45)
|
43
+/-
4 (45)
|
62
+/-
7 (67)
|
| 6 |
121
+/-
9 (125)
|
223
+/-
38 (235)
|
47
+/-
5 (47)
|
48
+/-
4 (47)
|
62
+/-
6 (67)
|
| 7 |
70
+/-
9 (65)
|
229
+/-
18 (242)
|
36
+/-
5 (40)
|
48
+/-
6 (50)
|
85
+/-
10 (95)
|
| 8 |
74
+/-
5 (82)
|
204
+/-
13 (205)
|
45
+/-
4 (50)
|
45
+/-
3 (50)
|
77
+/-
10 (85)
|
| 9 |
114
+/-
26 (120)
|
253
+/-
21 (250)
|
46
+/-
4 (50)
|
46
+/-
4 (50)
|
72
+/-
6 (75)
|
| 10 |
76
+/-
14 (82)
|
235
+/-
23 (250)
|
34
+/-
3 (37)
|
48
+/-
4 (50)
|
92
+/-
16 (100)
|
| 11 |
73
+/-
7 (70)
|
207
+/-
13 (210)
|
41
+/-
4 (45)
|
43
+/-
3 (42)
|
78
+/-
9 (85)
|
| 12 |
115
+/-
7 (115)
|
255
+/-
12 (260)
|
41
+/-
4 (45)
|
47
+/-
7 (50)
|
74
+/-
9 (77)
|
| 13 |
68
+/-
10 (60)
|
233
+/-
24 (245)
|
28
+/-
5 (32)
|
48
+/-
6 (55)
|
89
+/-
12 (90)
|
| 14 |
68
+/-
10 (60)
|
205
+/-
20 (210)
|
- |
| 15 |
93
+/-
9 (90)
|
226
+/-
21 (247)
|
28
+/-
3 (32)
|
45
+/-
5 (52)
|
67
+/-
8 (75)
|
| 16 |
72
+/-
6 (80)
|
185
+/-
25 (200)
|
- |
| 17 |
110
+/-
8 (125)
|
172
+/-
21 (175)
|
Legs
.
First pair of legs reduced to 2 small hairy cupules, each with 1 long seta (9-10
μm
) (Fig.
1F
). Basal areas of legs 2-12 each with 3-8 setae (Fig.
1H
). Leg 12 0.8-0.9 time as long as length of head (Fig.
3I
), trochanter 1.1-1.2 times as long as wide (50-75
μm
, 41-67
μm
), with 7 setae; femur almost as long as wide (35-40
μm
, 30-40
μm
), with 5 setae and dorsal protruding longest setae (18-25
μm
) about 0.6 time of greatest diameter of podomere; tibia nearly1.6-1.9 times longer than wide (45-55
μm
, 25-30
μm
), with 5 dorsal setae: 3 straight and protruding, 2 slightly curved and depressed, longest setae 0.7-1.0 of greatest diameter of tibia, 2 ventral setae distinctly shorter than dorsal ones; tarsus cylindrical, about 3-4.3 times as long as wide (58-75
μm
, 16-19
μm
) with 6 dorsal setae: 3 or 4 straight and protruding, others curved and depressed, longest setae (15-22
μm
) same with greatest width of podomere, 1 ventral seta close to claw distinctly shorter than dorsal ones. Claws curved, anterior one somewhat broader than posterior one, posterior one more curved than former. Trochanter and femur with cuticular thickenings in pattern of large scales laterally (Fig.
3I
). All legs covered with dense pubescence except areas with cuticular thickenings.
Coxal sacs
present at bases of legs 3-9, fully developed, each with 4 or 5 setae on surface (Fig.
1H
). Corresponding area of leg 2, 10, 11, and 12 replaced by 2-4 setae respectively.
Styli
present at base of legs 3-12, slender (length 6-9
μm
, width 4-6
μm
), basal part with dense straight hairs; distal quarter hairless and with blunt apex (3-5
μm
) (Fig.
1H
).
Sense calicles
located on 2 ventral protuberances of last tergite, posterior to base of leg 12, with smooth margin around pit. Sensory seta inserted in cup center, extremely long (110-140
μm
).
Cerci
about 0.5-0.6 of head length, 2.5-3 times as long as its greatest width (125-170
μm
, 50-63
μm
), densely covered with 75-90 subequal setae (Figs
1I-J
,
3F-G
). Two types of setae inserted on cercus: 7 and 8 long and erect setae located in outer side, and others slightly curved and depressed. Longest outer seta (25-30
μm
) 0.4-0.6 of greatest width of cerci (Figs
1J
,
3F-G
), terminal area short (25-30
μm
), circled by 9 layers of curved ridges. Terminal setae (25-32
μm
) almost as long as terminal area (Figs
1I
,
3F-G
).
Etymology.
From the Greek words
"macro"
meaning
"large"
and
"chaeta"
meaning
"seta"
. The species name "
Symphylella macrochaeta
" is feminine and refers to extremely long setae on the frons.
Distribution.
China (Shanghai, Zhejiang).
Remarks.
Symphylella macrochaeta
sp. nov. has 10 extremely long macrosetae on the frons, which can distinguish it from all other congeners. It is similar to
S. communa
from East China and
S. asiatica
Scheller, 1971 from India and Sri Lanka in the shapes of the central rod, tergites, and leg 12, but the new species differs in the chaetotaxy of the first tergite (4+4 setae in
S. macrochaeta
sp. nov. and
S. communa
vs 3+3 setae in
S. asiatica
) and in the shape of stylus (slender in
S. macrochaeta
sp. nov. vs subconical in
S. communa
and conical in
S. asiatica
). The new species can also be compared to
S. macropora
from Tibet in the shape of tergites and processes, but it can be easily separated by the shape and the size of the opening of the
Toemoesvary
organ (moderate and round in
S. macrochaeta
sp. nov. vs large and elongate in
S. macropora
).