Two new camaenid land snails (Eupulmonata) from Central China
Author
Wu, Min
Author
Chen, Zheyu
Author
Zhu, Xiaoran
text
ZooKeys
2019
861
129
144
http://dx.doi.org/10.3897/zookeys.861.35430
journal article
http://dx.doi.org/10.3897/zookeys.861.35430
1313-2970-861-129
DAD076A6B8B74FEE94C4CFB56E0B6338
Bradybaena linjun Wu & Chen
sp. nov.
Figs 1
,
7
,
8
,
9
,
10
Material
examined.
Holotype
, fma (HBUMM08241-specimen 1,
Fig. 7A
). Hubei Province, Yichang, Changyang Tujia Autonomous Prefecture, Longzhoupin;
31°28'9"N
,
111°11'14"E
, 103 m a. s. l.; 2018-VII; coll. Chen, Zheyu.
Paratype
, 1 fma (HBUMM08241-specimen 2,
Fig. 7B
), the same collection information as holotype. Foot muscle was cut off and preserved in 99.7% alcohol at -20 °C (HBUMM08242).
Figure 7.
Bradybaena linjun
Wu & Chen, sp. nov.
A
holotype, HBUMM08241-specimen 1
B
paratype, HBUMM08241-specimen 2.
Diagnosis
.
Shell depressed; dextral. Columella oblique. Periphery rounded. A peripheral and a supraperipheral chestnut band present. Penis internally with numerous crossing pilasters of equal thickness that form a network. Love dart hollow and C-shaped in cross section. Accessory sac externally invisible. Mucous glands two, very short thyrsiform (not branched) tubes; entering accessory sac through simple pore. Shell about 4.5 whorls, breadth 13-17 mm.
Description.
Shell (
Fig. 7
). Depressed; thin; dextral. Whorls convex. Suture impressed. Half umbilicus covered by reflexed columellar lip. Columella oblique. Proto
conch
not granulate, smooth. Teleoconch with dense spiral furrows. Aperture oblique; not sinuate at peristome. Body whorl slightly descending behind aperture. Shell surface without ribs. Growth lines fine. Adult shell not hairy or scaly. Adult body whorl rounded at periphery; basally convex. Ring-like thickening within aperture absent. Peristome thin; slightly reflexed. Callus thin and transparent. Shell glossy; uniformly brownish yellow; with a peripheral and a supraperipheral chestnut bands. Measurements (holotype is larger in size): shell height 8.8-10.7 mm, shell breadth 13.2-16.6 mm, aperture height 5.9-6.0 mm, aperture width 7.0-9.7 mm, embryonic shell whorls 1.625, whorls 4.250-4.625, shell height/ breadth ratio 0.64-0.67.
General anatomy (
Figs 8
,
9F
). A high head wart between ommatophores present (
Fig. 8A, C
). On corresponding internal body wall no particular structure present (
Fig. 8D
). On left side of mantle edge, a leaf-shaped appendage present (
Fig. 8B
, arrowed). Body light brown; with whitish striae posterior to wart. Sole creamy white. Jaw arcuate; with about thirteen more or less projecting ribs (
Fig. 9F
).
Figure 8.
Bradybaena linjun
Wu & Chen, sp. nov., holotype, HBUMM08241-specimen 1.
A, C
showing head wart
B
leaf-shaped appendage (arrowed) on left margin of mantle
D
internal body wall between ommatophore insertions, showing no gland.
Figure 9.
Bradybaena linjun
Wu & Chen, sp. nov., holotype, HBUMM08241-specimen 1.
A, B
both sides of genitalia, general view
C
bottom of dart apparatus, showing mucous glands insertion
D
penis, exposed
E
love dart in cross section
F
jaw. Scale bars: 1 mm. At - atrium; BCD - bursa copulatrix duct; DS - dart sac; DVM - membranous sac surrounding terminal genitalia; Ep - epiphallus; FO - free oviduct; MG - mucous glands; P - penis; PR - penial retractor muscle; PS - penis sheath; Va - vagina; VD - vas deferens.
Genitalia (
Fig. 9
). Membranous sac surrounding terminal genitalia present (
Fig. 9A, B
). Penis sheath about 1/3 penis length. Penis very thick; externally simple. Penial retractor muscle inserting on epiphallus. Epiphallus slightly thicker than vas deferens. Flagellum absent. Epiphallic papilla absent (
Fig. 9D
). Penis internally with numerous crossing pilasters of equal thickness that form a network (
Fig. 9D
). Dart sac
present
. Love dart spoon-shaped, hollow and C-shaped in cross section (observed in holotype,
Fig. 9E
). Accessory sac invisible externally (
Fig. 9C
). Poly-layered structure present between mucous gland insertion and vagina. Mucous glands two tubes; much shorter than dart sac in length; each thyrsiform rather than branched (
Fig. 9A, C
); entering accessory sac through simple pore. Vagina about half of penis in length. Measurement of holotype:
DS-
4.6 mm long, 1.4 mm broad;
MG-
1.7 mm;
PS-
1.2 mm;
P-
7.1 mm;
Ep-
2.6 mm;
VD-
21.5 mm;
PR-
1.7 mm;
Va-
4.5 mm;
FO-
2.8 mm.
Etymology.
The new species is named after the legendary tribal leader "Lin-Jun (
廪君)"
of the Tujiazu people who live at the type locality.
Distribution.
Hubei (Changyang), only known from the type locality.
Ecology
.
This species was found living in a well-established secondary forest, on limestone cliffs, often in cracks (
Fig. 10
). A large number of broken shells, presumably caused by bird predation, were observed at the type locality.
Figure 10.
Bradybaena linjun
Wu & Chen, sp. nov., holotype, HBUMM08241-specimen 1. Habitat, photographer Zheyu Chen.
Taxonomic remarks.
The new species is assigned to
Bradybaena
because of the presence of a smooth protoconch, membranous sac surrounding terminal genitalia, poly-layered structure in dart apparatus, two mucous glands and the absence of a flagellum; characters that are consistent with the type of the genus
B. similaris
(
Wu 2004
).
On the left side of the mantle edge, this species possesses a leaf-shaped appendage (
Fig. 8B
). The existence of this structure in other bradybaenine genera is not known except in
Sinochloritis lii
Wu & Chen, gen. & sp. nov. described here (
Fig. 3D, E
). In our other work on
Bradybaena
this structure is observed (
Bradybaena
sp., HBUMM06125, Wuyuan, Jiangxi Province, 147 m,
29°22'18.8"N
,
118°02'45.2"E
, 2007-V-26; unpublished data).
Only a few Chinese species in the subfamily
Bradybaeninae
have double bands. The double-banded shells occur more frequently in
Cathaica
Moellendorff
, 1884 than in
Bradybaena
where only four species exhibit double bands, namely
B. billiana
(Heude, 1882),
B. mimicula
(Heude, 1888),
B. diplodesma
(
Moellendorff
, 1899),
B. sueshanensis
Pilsbry, 1934 (
Heude 1882
,
1888
;
Moellendorff
1899
;
Pilsbry 1934
). Although the new species has double bands, in aspect of shell morphology it most resembles
B. qixiaensis
Wu & Asami, 2017. However, the new species has very short mucous glands which are proportionally the shortest in the subfamily
Bradybaeninae
, the thyrsiform mucous gland duct, and the spoon-shaped love dart, which distinguish this species from all Chinese
Bradybaena
species with known genital anatomy.