Research Article |
Corresponding author: Shu-Ping Wu ( shupingwu@ntu.edu.tw ) Academic editor: Frank Köhler
© 2018 Chung-Chi Hwang, Shu-Ping Wu.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Hwang C-C, Wu S-P (2018) Two new species of Satsuma A. Adams, 1868 from Taiwan (Pulmonata, Camaenidae). ZooKeys 795: 115-126. https://doi.org/10.3897/zookeys.795.28958
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Two new sinistral species of the genus Satsuma A. Adams, 1868, Satsuma squamigera sp. n. and Satsuma adiriensis sp. n., from southern Taiwan are described. Satsuma squamigera sp. n. is characterized by a microsculpture comprising coarse, irregularly-spaced ridges and dense, easily-dislodged triangular scales on its sinistral shell, an angulated periphery, and partly-opened umbilicus. This species inhabits secondary forests in lowland hills. Satsuma adiriensis sp. n. is characterized by a thin, fragile smooth shell with microsculpture of coarse, loose ridges, a rounded periphery, completely-opened umbilicus, and elongated penial verge formed by two main pilasters. This new species was collected in a mountainous, mid-elevation, broad-leafed forest.
anatomy, Gastropoda , land snail, sinistral, Stylommatophora , taxonomy
The family Camaenidae, which includes the confamilial Bradybaeninae, is widely distributed in Asia and Australasia (
To date, 46 species have been described from Taiwan; most of them are endemic to Taiwan and narrowly distributed (
Specimens of the new species were collected in southern Taiwan (Figure
Abbreviations
Genitalia:
ag albumen gland;
at atrium;
bc bursa copulatrix;
ep epiphallus;
fl flagellum;
fod free oviduct;
p penis;
pc penial caecum;
pd pedunculus of the bursa copulatrix;
rm retractor muscle;
sod spermoviduct;
v verge;
va vagina;
vd vas deferens.
Shell measurements:
AH aperture height;
AW aperture width;
SH shell height;
SW shell width;
W# number of whorls
Type species. Helix japonica Pfeiffer, 1847, by subsequent designation (
Holotype
Taiwan: Pingtung County, Shih-tze, Ka-yo-fong waterfall (also named Nei-shih waterfall), 22°17.55'N; 120°41.88'E, alt. 170 m, secondary lowland broad-leafed forest (Figure
Distribution map of two Satsuma species in southern Taiwan. A–D S. squamigera sp. n.: A Ka-yo-fong waterfall, Shih-tze, Pingtung (type locality) B Da-han- shan forest road, Pingtung C Mt. Bei-li-long, Pingtung D Mu-dang, Pingtung; E–H S. adiriensis sp. n.: E A-li, Wu-tai, Pingtung (type locality) F Shan-ping, Liu-guei, Kaohsiung G Mt. Fan-bao-jian, Nan-xi, Tainan H Ma-jia, Pingtung.
Shell sinistral with coarse and irregularly ridged and fine striations; surfaces with dense, fine, erected, triangular scales falling off easily; periphery angulated, umbilicus partly opened; penial caecum short, internally with elongated verge formed by two main pilasters.
Shell. Measurements (n = 11): SH 12.1–13.9 mm, SW 18.5–20.7 mm, AH 6.9–8.2 mm, AW 11.0–12.2 mm, W# 5.5–5.75, SH/SW 0.61–0.71; sinistral, with low conical spire, light brown to dark brown with red-brown peripheral band and umbilicus spot. Apex obtuse. Whorls regularly increasing, slightly convex. Periphery angulated. Base of shell convex. Surface completely covered with dense, fine, erected, curved, triangular, easily-dislodged scales and leaving crescent-shaped trace; upper surface with coarse, oblique axial ridges; spiral striation absent. Aperture roundly lunate. Peristome expanded; outer lip smoothly curved; columellar lip oblique, curve, joining curved basal lip smoothly or in an angle. Parietal callus smooth, thin, transparent. Umbilicus open, 2.6–3.2 mm in width, 1/5 covered by reflected columellar lip.
External morphology. Light brown with irregular, small, dark brown spots and a distinct yellowish line running from head between tentacles to collar. Tentacles dark brown.
Reproductive system. Bursa copulatrix oval with long pedunculus of 27–30 mm. Free oviduct short. Vagina muscular, furrowed externally corresponding to internal folds, 10–12 mm in length. Atrium short, finely wrinkled inside. Penis slender, 10–12 mm in length, evenly thickened, furrowed externally corresponding to 7–8 strong, straight, corrugated pilasters internally. Penial caecum short, protruding 2–3 mm. Verge extending along penial caecum, formed by two main pilasters, with wrinkled surface. Epiphallus slender, 15–17 mm in length, internally with 4 smooth pilasters. Penis retractor muscle attached at distal 1/4 of epiphallus. Flagellum short, tapering.
From squamigera (Latin, adjective in the nominative feminine singular case) meaning scale-bearing, for the scaly shell surface.
This species was found in southern Pingtung County, including the type locality, Da-han-shan forest road (22°24.20'N; 120°45.31'E, alt-1555 m), Mt. Bei-li-long (22°11.81'N; 120°43.63'E, alt-320 m) and Mu-dang (22°8.43'N; 120°48.34'E, alt-240 m) (Figure
All specimens were collected in mountainous, lowland, broad-leafed forest. Mature adults were collected in mid-May and February, from ground, rocks or fallen tree trunks. This species is sympatric with the congeners Satsuma bacca (Pfeiffer, 1866), Satsuma batanica pancala (Schmacker & Boettger, 1891) and Satsuma longkiauwensis Wu, Lin & Hwang, 2007.
Satsuma squamigera sp. n. is distinguished from all other sinistral species by having dense and curved scales on the whole shell surface. When fully matured, the scales typically fall off, leaving crescent-shaped granules. Some intact scales may remain beside sutures, on the base of the last whorl or inside the umbilicus. The new species is similar to S. pekanensis (Rolle, 1911) and S. submeridionalis (Zilch, 1951) in shape of shell and angulated periphery. In comparison to S. pekanensis, the new species has a shortened spire and an extended flagellum (
Holotype
Taiwan: Pingtung County, Wu-tai, A-li, 22°43.42'N; 120°45.44'E, alt. 1350 m, disturbed primary broad-leaf forest.
Shell sinistral, thin, fragile, smooth, with spaced, coarse ridges; periphery round, color band absent; umbilicus completely opened; penial caecum long, internally with elongated verge formed by two main pilasters.
Shell. Measurements (n = 3): SH 10.8–12.9 mm, SW 17.4–20.6 mm, AH 6.9–8.5 mm, AW 8.6–10.3 mm, W# 5.5, SH/SW 0.61–0.68; sinistral, thin, fragile, semi-translucent, with low conic spire, light brown, without color band. Apex obtuse. Whorls regularly increasing, slightly convex. Periphery bluntly angulated on the first 3/4 of last whorl, becoming rounded 1/4 whorl before peristome. Base of shell convex. Surface covered with loose, coarse, oblique axial ridges, becoming thin on base; spiral striation absent. Aperture roundly lunate. Peristome expanded; outer lip smoothly curved; columellar lip sub-vertical, not reflected, joining with basal lip in a weak angle. Parietal callus smooth, thin, transparent. Umbilicus completely opened, 3.3–3.6 mm in width.
External morphology. Light brown with dense, irregular, dark brown to black spots and a distinct yellowish line running from head between tentacles to collar. Tentacles dark brown.
Reproductive system. Bursa copulatrix oval; pedunculus long, 31 mm in length, with slightly expanded base. Free oviduct short. Vagina thickened, smooth externally, with eleven internal pilasters, 11 mm in length. Atrium obvious, finely wrinkled inside. Penis muscular, 13 mm in length, evenly thickened, furrowed externally; distal half internally supporting three main, finely wrinkled pilasters; proximal half supporting eleven strong, corrugated pilasters. Penial caecum thickened, with blunt apex, protruding 7 mm. Verge extending along penial caecum, formed by two main pilasters. Epiphallus slender, 16 mm in length, internally with three smooth pilasters. Penis retractor muscle attached at distal 1/6 of epiphallus. Flagellum long, tapering, slightly wavy at middle portion.
For Adiri, the indigenous Rukai name of the type locality, adjective of feminine gender.
Known from mid-elevation forest of Kaohsiung, Tainan and Pingtung (Figure
All specimens were collected in mountainous, mid-elevation, broad-leaf forest. The single live adult was collected in July, from a tree trunk. This species is sympatric with congeneric species S. albida (Adams, 1870) and S. friesiana (Moellendorff, 1884) at Shan-ping, S. amblytropis (Pilsbry, 1901) at Mt. Fan-bao-jian and an unknown Satsumaat the type locality A-li. Despite wide distribution in the mountainous areas of southwestern Taiwan, this species is quite rare.
Satsuma adiriensis sp. n. is similar to S. contraria (Pilsbry & Hirase, 1909), distributed in Kenting, Pingtung, in having a sinistral, semi-transparent shell with completely open umbilicus. The new species, however, has smaller shell width, round periphery on the final 1/4 of the last whorl, a sub-vertical columellar lip, a sinuous upper lip, coarse ridges on the surface, a slender pedunculus of bursa copulatrix, and a longer penial caecum and flagellum and shorter penis than the latter species (
The new species shares a sinistral and depressed conic shell with Satsuma formosensis (Pfeiffer, 1866) and S. yaeyamensis (Pilsbry, 1894), which are found in northern Taiwan and the Ryukyu Islands. Satsuma adiriensis differs from these two species by its thin, semi-transparent shell with loose, coarse surface ridges, a sub-vertical columellar lip joining basal lip in a weak angle, and a bluntly angulated periphery on the first 3/4 of the last whorl.
In this study, two new species of sinistral Satsuma were described based on shell and reproductive system characteristics. This work has brought the number of known sinistral Satsuma species to seventeen. Among these seventeen species, eleven are distributed in Taiwan, three in the Ryukyu Islands, two in southern China, and one in Batan Island, Philippines. The diversification of Satsuma has been explained by allopatric speciation (
Periostracal ornamentations such as granules and hairs are commonly seen in confamilial genera, e.g., Chloritis Beck, 1837, Moellendorffia Ancey, 1887, Aegista Albers, 1850 and many genera from Australia (
Short, hooked hairs have been observed over the entire shell surface of the sinistral species S. uncopila (Heude, 1882). Granules on the entire shell surface are also reported in some dextral species, e.g., S. ferruginea (Pilsbry, 1900), S. textilis (Pilsbry & Hirase, 1904), S. japonica granulosa (Pilsbry, 1902), S. j. heteroglypta (Pilsbry, 1900), S. okiensis (Pilsbry & Hirase, 1908) and S. cristata (Pilsbry, 1902). The hairs are thought to promote the snails’ adherence to leaves when humidity levels are high (
Author contributions
CC Hwang performed the anatomical studies, executed this study, and wrote the manuscript; SP Wu helped with the data collecting and paper writing.
We gratefully acknowledge the assistance of Dr. Hsueh-Wen Chang, Dr. Gao-Shih Hsiang, Ms. Su-Chin Chang, Mr. Chang-Yi Tsai (National Sun Yat-Sen University), Mr. Hsin-Te Yang (Da-Yeh University), Mr. Wei-Hsuan Tsai, Bo-An Lee, Wan-Bao Lee and Chi-Kai Liao (National University of Kaohsiung) and Mr. Chao-Ching Lee in the field works. Thanks are also due to Mr. James Bell for his editorial assistance. This study was partially supported by the Ministry of Science and Technology Grant (MOST 107-2321-B-845-001 -), We also wish to express our gratitude to Forestry Bureau and Taiwan Forestry Research Institute, Council of Agriculture for the permission for collection.