A new Dicranocentrus species (Collembola: Entomobryidae) from China with a key to all species in the genus from Asia
Author
Ma, Yitong
Author
Chen, Jian-Xiu
text
Zootaxa
2007
1633
63
68
journal article
10.5281/zenodo.179448
ec72682c-9c77-4566-b291-095b74bb7bcc
1175-5326
179448
Dicranocentrus wangi
sp. nov.
Figs. 1–22
,
Tabs. 1
–2
Description.
Body length up to
2.5mm
. Ground colour pale yellow. Eye patches dark blue. One small blue spot present between antennae. Blue pigment gradually darker from distal part of 2nd to 6th antennal segments and from distal part of femur to tibiotarsus (
Fig. 1
).
FIGURES 1–12.
Dicranocentrus wangi
sp. nov.
: 1, habitus; 2, eyes; 3, antenna; 4, apex of Ant. VI; 5, dorsal cephalic chaetotaxy; 6, seta of posterior margin of head; 7, labrum; 8, differentiated seta of external labial papilla; 9, maxillary palp; 10, labial chaetotaxy; 11, semi-diagrammatic dorsal chaetotaxy of Th. II-Abd.IV; 12, trochanteral organ.
Head. Eyes 8+8, G and H smaller than others (
Fig. 2
). Antennae short, 0.50–0.76 times as long as body and 2.3–3.7 times as cephalic diagonal; ratio of length of ant. V to VI as 1.2–2.3; Ant. V and VI annulated except proximal part of ant. V (
Fig. 3
); apex of Ant. VI with 1–2 finger-like bent setae and without pin-like seta (
Fig. 4
). Dorsal cephalic chaetotaxy as in
Fig. 5
, A1 and Ps absent and S2 present, P group with 5 setae (after
Mari
Mutt 1979
), 30–64 short ciliate setae present along posterior margin of head (
Fig. 5 and 6
). Labral setae 4/5,5,4, all smooth; distal margin of labrum with 4 broad, oval papillae, each papilla with 1 small seta (
Fig. 7
). External differentiated seta of labial appendage thinner than normal setae, short, with tip reaching basal half of papilla (
Fig. 8
). Apical seta of maxillary palp similar in shape and as long as or slightly longer than subapical seta (
Fig. 9
). Setae of posterior row of labial triangle variable, internal to setae with 0–5 ciliate setae and 2–6(9) smooth. Seta R of labial triangle 0.54–0.72 as long as M1 (
Fig. 10
).
Thorax. Macrochaetae as shown in
Fig. 11
(setae with an arrow sometimes absent). Trochanteral organ with 25–41 setae (
Fig. 12
). Besides numerous ciliate setae of different sizes, tibiotarsus with 0–2 smooth setae on outer side and 5–12 smooth setae arranged in 2–3 files on inner side. Tenent hair acuminate, 0.75–1.00 times as long as inner edge of unguis. Unguis with 3 inner teeth, basal pair small and sub-equal, median one minute. Unguicular outer tooth usually absent, rarely present (in
paratype
, female 8717-F) and minute (
Fig. 13
).
Abdomen. Macrochaetae and bothriotricha as shown in
Fig. 11
. Length ratio of abd. IV to abd. III at dorsal midline as 1.3–1.8. Tenaculum with 4+4 teeth and 4–10 weakly ciliate setae on corpus (
Fig. 14
). Ventral tube scaled on both faces, anterior face with 11–22 ciliate to weakly ciliate setae on each side (
Fig. 15
); posterior face with 36–78 weakly ciliate to smooth setae (
Fig. 16
); each lateral flap with 28–50 smooth setae (
Fig. 17
). Manubrium with numerous ciliate setae of different sizes, 23 and 25 smooth setae on each side (in
paratype
, female 8717-XXX) (
Fig. 18
). Manubrium plaque with 1–2 smooth setae, 9–13 strongly ciliate setae and 2–3 pseudopores (
Fig. 19
). Length ratio of manubrium to dens as 0.50–0.71. Proximal dens with 1–4 smooth setae. Dental lobe with a ciliate blunt seta and a row of 4–7 ciliate setae. Dental spines simple, 8–13, chestnut coloured, arranged in one file along inner edge of dentes (
Fig. 20
). Ratio of length of uncrenulatd part of dens to mucro 3.1–4.3. Mucro bidentate, basal spine short, smooth, with tip reaching subapical tooth (
Fig. 21
).
Scales chestnut coloured, hyaline and heavily striated (
Fig. 22
).
Ecology.
In leaf litter of deciduous trees.
Type
material.
Holotype
female,
China
: Guangdong Province: Guangzhou: South
China
Plantation,
10.viii.1999
, coll. Chen Jian-xiu and Wang Song-jie, collection number 8717-C;
paratypes
:
3 males
and
53 females
on slides, same data as
holotype
(8717-series); in the Department of Biology, Nanjing University.
Etymology.
The new species is named after Mr. Wang Song-jie who collected the specimens for the present study.
Remarks.
The new species is clearly different from
D. indicus
, the only known Chinese species in the genus, by the characters given in
Table 1
.
TABLE 1.
Main differences between
D. indicus
and
D. wangi
.
indicus
|
wangi
|
Dental spines |
absent |
8–13 |
Smooth setae on tibiotarsus |
absent |
7–14 |
Apex of tenent hair |
slightly clavate |
acuminate |
Macrochaetae on Abd. IV |
absent |
4+4 or 5+5 |
The new species is most similar in the arrangement of dental spines to the
Philippine
species
D. luzonensis
Mari
Mutt, 1985
and the
Singapore
species
D. simplex
Yosii, 1959
, but differs from them as shown in Table 2.
TABLE 2.
The main differences between
D. wangi
,
D. luzonensis
and
D. simplex
.