Research Article |
Corresponding author: Somsak Panha ( somsak.pan@chula.ac.th ) Academic editor: Frank Köhler
© 2019 Chirasak Sutcharit, Fred Naggs, Jonathan Ablett, Pham Van Sang, Luong Van Hao, Somsak Panha.
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:
Sutcharit C, Naggs F, Ablett J, Sang PV, Hao L, Panha S (2019) Notes on the sinistral helicoid snail Bertia cambojiensis (Reeve, 1860) from Vietnam (Eupulmonata, Dyakiidae). ZooKeys 885: 1-14. https://doi.org/10.3897/zookeys.885.38980
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Since the time of the original description there have been no precise locality records in Cambodia of Bertia cambojiensis (Reeve, 1860) and it was believed to be extinct. In 2012, a joint Natural History Museum survey with Vietnamese colleagues rediscovered living populations of this huge sinistral helicoid snail in a protected area of southern Vietnam. The genitalia and radula morphology are re-assessed and type specimens of all recognised congeners are figured herein. The unique morphological characters of this species are a small and simple penis, well-developed amatorial organ complex that incorporates four amatorial organ ducts, a short gametolytic organ complex and spiked papilla, and radula morphology with unicuspid teeth. The type locality of B. cambojiensis, which has been contentious, is determined here to be in the vicinity of ‘Brelum’, Vietnam, near the border with Cambodia. In addition, the nucleotide sequences of barcoding genes COI, 16SrRNA and 28S fragments were provided for further comparison.
Conservation, DNA barcoding, endangered, left-handed, systematics
The Dyakiidae Gude & Woodward, 1921, are a family of helicoid land snails restricted to Southeast Asia. The apomorphic characters of the family are the presence of an amatorial organ complex comprised of amatorial organ glands, amatorial organ ducts and amatorial papilla with a conchiolin spike (
Bertia cambojiensis (Reeve, 1860) was originally described under the name Helix mouhoti Reeve, 1860 [September], based on specimens collected by the famous French naturalist Henri Mouhot. Since this combination was a junior primary homonym of
Living populations of B. cambojiensis were discovered on a 2012 survey in Cat Tien National Park organized by the Vietnam National Museum of Nature (VNMN) and the Natural History Museum, London (NHM). Bertia cambojiensis were listed as Critically Endangered (CR) on the IUCN Red List of Threatened Species (2014) due to their apparent restricted distribution in lowland tropical forest patches. In addition to deforestation and habitat degradation, threats include use as food and as a traditional medicinal resource (
All voucher specimens deposited in the NHM, London were examined. Two preserved specimens in 70% ethanol (NHMUK 20130833 and 20130874) were dissected for examination of the genitalia, and radulae were extracted and examined under a scanning electron microscope (JEOL, JSM-5410 LV). The radula shape and teeth formula were observed and recorded. Cytochrome c oxidase subunit I (COI), 16S ribosomal RNA (16S) and 28S ribosomal RNA (28S) genes of B. cambojiensis samples were sequenced for DNA barcoding. For DNA extraction and PCR amplification conditions and amplified primers see Appendix
am amatorial organ;
amd amatorial organ duct;
amg amatorial organ gland;
amp amatorial organ pilaster;
at atrium;
e epiphallus;
fo free oviduct;
go gametolytic organ (duct and sac);
ov oviduct;
p penis;
pg prostate gland;
pp penial pilaster;
pr penial retractor muscle;
v vagina;
vd vas deferens;
vp vaginal pilaster.
Bertia
Ancey, 1887: 53.
Ariophanta (Bertia) Thiele, 1931: 1001.
Helix cambojiensis Reeve, 1860, by original designation.
Helix mouhoti
Reeve, 1860a [Sep.]: 203, 204 [not
Helix cambojiensis
Reeve, 1860b [Dec.]: 455 [new replacement name].
Helix cambodjensis:
Nanina cambodgiensis:
Ariophanta (Rhyssota) cambojiensis:
Bertia cambodjiensis:
Bertia cambojiensis:
Two syntypes from the Cuming collection. The specimen figured by
All additional specimens were from the area of Cat Tien National Park, Dong Nai Province, Vietnam (11°26.147"N, 107°25.643"E): NHMUK 20130818 from Lodge Gardens (4 specimens + 2 juveniles); NHMUK 20130833 from Cave Site (7 specimens + 1 juvenile; Fig.
Shell. Shell sinistral, large, dome shape and thickened. Whorls 6 to 7, increasing regularly, slightly convex, and with wide and shallow suture. Periostracum thin to slightly thickened, corneous. Spire convex, apex obtuse, embryonic shell large with smooth surface, following whorls possess a series of thin nodules on growth lines. Last whorl well rounded. Upper shell surface glossy, varying from rich cream and brownish to blackish bands; narrow pale white to yellowish spiral band on periphery; narrow reddish-brown to dark subsutural band. Below periphery always with reddish-brown to dark colour and with broad white spiral band surrounding umbilicus. Umbilical area usually reddish-brown or darker. Aperture ovate; parietal callus translucent whitish; columella thickened and slightly dilated. Lip simple or slightly thickened in old adults. Umbilicus narrowly perforate to rimate and deep.
Genital organs.
Atrium (at) very short (N = 2). Penis (p) long cylindrical tube. Penial retractor muscle (pr) short, thickened and attached distally to penis. Epiphallus (e) cylindrical tube, about half of penis length and slightly smaller diameter than distal penis. Vas deferens (vd) relatively smaller diameter and thin tube extending from free oviduct (fo) and entering epiphallus, apically; flagellum absent (Fig.
Gametolytic organ (go; duct and sac undifferentiated) proximal to genital opening about one-fourth of amatorial organ length. Slightly swollen proximally, then tapering to small, long cylindrical tube and attached to ovary with thin connective tissues. Amatorial organ (am) well-developed enlarged cylinder; proximally attached to atrium. Amatorial organ glands (amg) enlarged, composed distally of four major lobes bounded to amatorial organ by thin connective tissue. Each of four major lobes of the amatorial organ gland extend proximally into thick amatorial organ ducts (amd) that are twisted together and bound with thin connective tissue before entering the distal tip of the amatorial organ (Fig.
Vagina (v) long enlarged cylinder, about the same length as penis. Free oviduct (fo) cylindrical tube; oviduct (ov) long with lobules; prostate gland (pg) bound to oviduct. Most of albumen gland, hermaphroditic duct and gland missing from figured specimen (Fig.
Radula. Teeth arranged in wide angle V-shaped rows with approximately 245 teeth with formula ((124-118)-1-(120-122)). Central tooth symmetric unicuspid and triangular. Lateral and marginal teeth undifferentiated, slightly curved unicuspid, triangular, and inclined towards central tooth (Fig.
Genitalia and radula of Bertia cambojiensis, NHMUK 20130833. A overview of genital system B–D internal wall sculpture of B penis C amatorial organ and D vagina E, F SEM image of radula E central and inner latero-marginal teeth and F outermost teeth. Numbers indicate tooth order from lateral to marginal end; central tooth indicated by ‘C’.
External features. Living snail with long, blackish-brown tentacles. Skin reticulated brown with black reticulations around head. Foot sole relatively elongated, broad and unipartite. Sole of foot brownish to orange and unspotted; side of body brownish. Tail curved mid-dorsally, tall dome-shaped in cross section. Caudal horn not overhanging; caudal foss long vertical slit in tail above sole margin. Typical aulacopoda with well-defined pedal groove.
Mantle collar large and shell lobes thickened, shell lappet absent. Right dorsal lobe (right side of anus) large and thickened. Left dorsal lobe (left side of anus) composed of thick crescentric anterior left dorsal lobe and thin elongated posterior left dorsal lobe. Pulmonary cavity typically sigmurethran.
The range of B. cambojiensis is likely to be confined to localised forest patches within Dong Nai, Binh Thuan, Lam Dong and Binh Phuc provinces. Records far outside of this range such as Ba Vi National Park (
The specimens from southern Vietnam that we examined exhibit clear differences in genital anatomy from those described by
In December 1858, the French explorer and naturalist Henri Mouhot set off from Bangkok by sea to the port of Komput (Kampot), Cambodia, from where he continued on his destination to Brelum in Annam (Vietnam), He reached the Catholic Mission in Brelum in August 1859.
According to
Rhyssota pergrandis Smith, 1893: 11, with text figure. Type locality: Annam.
Nanina pergrandis:
Ariophanta pergrandis:
Bertia pergrandis:
Syntype NHMUK 1893.2.26.1 (1 shell, Fig.
Ariophanta ranges from India to Indochina (
Bertia setzeri
Thach, 2015: 240, 241, figs 1–4, 17–20. Type locality: Khanh Vinh District and Nha Trang outskirts, Khanh Hoa Province, central Vietnam.
Images of the holotype are shown in Figure
The authors are indebted to H. Taylor (NHM, London), and P. Callomon and K. Seizova (ANSP, Philadelphia) for imaging type material. The work at Chulalongkorn University was funded by the TRF Strategic Basic Research DBG 6080011 (2017–2019), The Thailand Research Fund (TRF-DPG628001), Center of Excellence on Biodiversity (BDC-PG2-160012) and the Ratchadaphiseksomphot Endowment Fund of Chulalongkorn University (WCU-58-016-FW). We wish to express our gratitude for public donations made in the exhibition galleries of the Natural History Museum that provided funding for the 2012 survey. We are grateful to the following for support in Cat Tien National Park: Nguyen Van Dien, Director, Pham Huu Khanh, Head of Scientific and International Co-operation and to Le Duc Khanh, Scientific Officer, for support in the field. In addition, we wish to express our gratitude to members of the Natural History Museum’s cross departmental participants in the survey who in addition to collecting their own samples also collected land snails.
Molecular methods
DNA was extracted from small pieces of mantle collar tissue using a NucleoSpin Tissue kit (MACHEREY-NAGEL), following the manufacturer’s protocol. The COI gene was amplified using the universal primers LCO1490 (5'-GGTCAACAAATCATAAAGATATTGG-3’) and HCO2198 (5'-TAAACTTCAGGGTGACCAAAAAAT-3’) (