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Research Article
Diversity and taxonomy of Vietnamese Pollicaria (Gastropoda, Pupinidae)
expand article infoRussell L. Minton, Phillip M. Harris§, Ernest North, Do Van Tu|
‡ University of Houston Clear Lake, Houston, United States of America
§ University of Alabama, Tuscaloosa, United States of America
| Vietnam Academy of Science and Technology, Hà Nội, Vietnam
Open Access

Abstract

Species in the genus Pollicaria (Gastropoda: Pupinidae) are conspicuous members of the southeast Asian land snail fauna. Originally erected in 1856, both the genus and its constituent species have been reorganized multiple times with the most recent treatment published in 2013. Collections of Vietnamese Pollicaria during 2014 and 2015 raised questions of the utility of currently used diagnostic shell characters and identification keys in species identification. An examination of the authors’ collections, combined with museum specimens, suggested that at least three species of Pollicaria occur or have historically occurred in Vietnam. It is suggested that P. rochebruni is a senior synonym of P. crossei and treat both taxa as conspecific. A second species, P. mouhoti, was believed to only occur in Cambodia, Laos, and Thailand. A possible third species, based only on previous karyotypic work, is discussed. Our data further suggest that shell features such as color and size lack consistent utility in species-level identifications in Pollicaria.

Key Words

Pollicaria rochebruni, Pollicaria crossei, Pollicaria mouhoti, Vietnam, pupinid

Introduction

The genus Pollicaria was erected by Gould (1856) to include large pupinid snails of southeastern Asia possessing the following characters: a thick ovate shell, distorted and flattened in the adult; a circular aperture; and an internal shoulder or groove inside the palatal edge of the peristome (Pain 1974). The taxonomy and systematics of Pollicaria have remained in flux for many years. At the same time he erected the genus, Gould (1856) described Cyclostoma pollex Gould, 1856 and made it the type species of Pollicaria. Benson (1859) erected the genus Hybocystis with Megalomastoma gravidum Benson, 1856 from Burma as the type species, recognizing that C. pollex was synonymous with the previously described M. gravidum. Haines described C. myersii Haines, 1858 from Siam, and three more species were described in Hybocystis: H. mouhoti Pfeiffer, 1862 from the Lao Mountains of Cambodia; and H. elephas de Morgan, 1885 and H. jousseaumi de Morgan, 1885 from the Perak region of Malaysia. Benson (1860) recognized that Hybocystis was a junior synonym of Pollicaria, but the former name remained in use until Pain’s (1974) revision. Crosse (1885) revised Hybocystis into two sections, one with H. elephas and its junior synonym H. jousseaumi and the other with H. gravida, H. mouhoti, and H. myersii. In 1887, two species of Hybocystis were described from Tonkin (northern Vietnam), H. rochebruni Mabille, 1887 and H. crossei Dautzenberg & d’Hammonville, 1887. Dautzenberg and Fischer (1905) equated H. rochebruni and H. crossei with H. gravida, indicating that any shell differences between species were not consistent but rather existed in a continuum between extremes.

Pain (1974) revised the then six nominal Pollicaria species into three based on shell morphology: P. gravida, including P. rochebruni and P. crossei; P. elephas; and P. myersii, including its junior synonym P. mouhoti. Kongim et al. (2010) provided karyotype analyses for P. gravida, P. elephas, and P. myersii, along with P. mouhoti as a separate species. They found karyotype differences between all four species and found two distinct karyotypes in Vietnamese P. gravida; their “big brown shell” and “small orange shell” samples differed in the centromere position of one chromosome pair (Kongim et al. 2010:127). However, they did not karyotype any topotypic P. gravida from Burma. Most recently, Kongim et al. (2013) reassessed Pollicaria using a combination of shell, radula, and reproductive characters and recognized six separate species: P. gravida, P. myersii, P. mouhoti, P. elephas, P. rochebruni, and P. crossei. They correctly recognized that not all Pollicaria possess the shouldering inside the peristome, and assigned the different karyotypes of Vietnamese P. gravida (Kongim et al. 2010) to P. rochebruni (“big brown shell”) and P. crossei (“small orange shell”). The two species were diagnosed in their key based on shell size and color; P. rochebruni is large (>40 mm) with a brownish shell, while P. crossei is small (<35 mm) with a bright orange shell (Kongim et al. 2013). Both species are thus separate from the small yellow-shelled P. gravida from Burma. Kongim et al. (2013) also provided revised distributions for all species and figured type and additional material.

While identifying Vietnamese land snails collected in 2015 by PMH and DVT, we found Kongim et al. (2013) to be problematic in identifying specimens of P. rochebruni and P. crossei. We noted specifically that smaller (30-35 mm) reddish-brown shells and larger (35-40 mm) orange shells were left unidentifiable by the key, and that species-specific characters of the key conflicted with the comparative characters listed by Kongim et al. (2013:28). Of additional interest were records of putative P. mouhoti from Lào Cai, Vietnam (Solem 1966), a species that Kongim et al. (2013) had restricted to Cambodia, Laos, and Thailand, and internet references to additional species in northeast Vietnam and southern China. In an effort to resolve the taxonomic and distribution issues presented by Kongim et al. (2013), we undertook a morphological and molecular examination of Vietnamese Pollicaria specimens, along with original descriptions and other literature relevant to the genus, to address two research questions. First, are P. rochebruni and P. crossei separate valid species? Second, beyond those specimens listed in Solem (1966), is there evidence of additional Pollicaria species in Vietnam?

Materials and methods

Specimens collected by the authors were vouchered at the Carnegie Museum of Natural History (CM), Philadelphia, Pennsylvania. Collection data for Vietnamese Pollicaria came from the following museums: Chulalongkorn University, Museum of Zoology, Bangkok, Thailand (CUMZ); Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts (MCZ); Florida Museum of Natural History, University of Florida, Gainesville, Florida (FLMNH); Museum National d’Histoire Naturelle, Paris, France (MNHN), Royal Belgian Institute of Natural Sciences (RBINS), and National Museum of Natural History, Smithsonian Institute, Washington D.C. (USNM). Specimens from MNHN, CUMZ, and RBINS were not made available, so we treated the identifications and locality data given in Kongim et al. (2013) as correct. All Vietnamese Pollicaria holdings from FLMNH, MCZ, and USNM were borrowed, identified by the authors based on Kongim et al. (2013), latitude and longitude coordinates estimated, and mapped with DIVA-GIS (Hijmans et al. 2008).

We also searched the Internet for shell dealers selling Pollicaria specimens from Vietnam and surrounding areas. While we lacked the funding to purchase specimens outright, we examined shell images and locality information from the dealer websites. Requests to formally include images and additional information in this manuscript went unanswered. We accepted that this information was not equivalent to that of vouchered specimens, but could be important in determining the diversity and distribution (Turney et al. 2015) of Pollicaria species.

Live Pollicaria specimens were collected in Vietnam by PMH, DVT, and local farmers in 2015, preserved in ethanol, and DNA was successfully sequenced from two of them. One individual collected south of Hoàng Liên National Park had a reddish-brown shell we identified as P. rochebruni; the other was collected from Cúc Phương National Park and had an orange shell that was consistent with P. crossei sensu Kongim et al. (2013). Using foot tissue we followed a standard CTAB and phenol/chloroform DNA extraction method (Saghai-Maroof et al. 1984), then amplified one mitochondrial (16S) and two nuclear (18S and 28S) gene fragments by PCR. Amplification conditions were the same for all fragments and included an initial denaturing step (94ºC for 120 s), 30 cycles (94ºC for 60 s, 50ºC for 60 s, 72ºC for 120 s), and a final extension step (72ºC for 10 minutes). We employed the following primer pairs: 16Sar and 16Sbr (Palumbi et al. 1991), 18S1F and 18S4R (Giribet et al. 1996), and 28SD1F and 28SD6R (Park and Ó Foighil 2000). Sequences were generated with the Sanger method on an ABI 3730xl by Genewiz (South Plainsfield, New Jersey, USA). Contigs were assembled in Geneious (BioMatters Ltd.) and combined with Cyclophoroidea data taken from GenBank (Table 1). Each gene fragment was aligned separately using MUSCLE (Edgar 2004) and the appropriate substitution model selected by Bayesian information criterion in IQTREE (Nguyen et al. 2015). The models chosen were HKY+G4 (Hasegawa et al. 1985) for 16S, JC+I+G4 (Jukes and Cantor 1969) for 18S, and TN+I+G4 (Tamura and Nei 1993) for 28S. The combined three gene dataset was analyzed under maximum likelihood in IQTREE allowing each gene partition to be optimized under its own model. Branch support was estimated using 10,000 ultra-fast bootstrap replicates (Minh et al. 2013) in IQTREE.

GenBank accession numbers for all taxa included in the phylogenetic analysis.

Species 16S 18S 28S
Acroptychia bathiei HM753491 HM753437 HM753380
Acroptychia milloti HM753492 HM753438 HM753381
Adelopoma tucma HM753534 HM753450 HM753393
Aperostoma palmeri DQ093479 DQ093435 DQ093458
Arinia paricostata HM753500 HM753441 HM753384
Bellamya bengalensis FJ405724 FJ405678 FJ405623
Cochlostoma elegans HM753489 HM753435 HM753378
Cochlostoma roseoli HM753490 HM753436 HM753379
Cochlostoma septemspirale HM753497 HM753423 HM753367
Cyclophorus aurantiacus JX474723 KJ407088 KF319206
Cyclophorus bensoni JX474670 KJ407082 KF319138
Cyclophorus cantori JX474718 KJ407089 KF319193
Cyclophorus hirasei AY010505 AF055644 HM003647
Cyclophorus latus HM753484 HM753430 HM753374
Cyclotus taivanus HM753485 HM753431 HM753375
Diplommatina canaliculata HM753504 HM753445 HM753388
Diplommatina gomantongensis HM753509 HM753451 HM753394
Diplommatina rubicunda HM753520 HM753477 HM753417
Diplommatina rubra HM753514 HM753456 HM753399
Japonia sp. HM753486 HM753432 HM753376
Leptopoma vitreum JX474741 KJ407147 KF319214
Opisthostoma austeni KC250904 KC250930 KC250955
Opisthostoma hailei KC250897 KC250923 KC250948
Opisthostoma mirabile HM753529 HM753466 HM753406
Opisthostoma obliquedentatum HM753530 HM753467 HM753407
Opisthostoma platycephalum KC250905 KC250931 KC250956
Opisthostoma tenerum KC250902 KC250928 KC250953
Palaina albata HM753531 HM753469 HM753409
Palaina striolata HM753533 HM753470 HM753410
Pollicaria cf. crossei KY359073 KY359075 KY359077
Pollicaria rochebruni KY359072 KY359074 KY359076
Pseudopomatias eos KP271244 n/a n/a
Pseudopomatias maasseni KM103252 n/a n/a
Pupina hosei HM753493 HM753439 HM753382
Pupinella swinhoei HM753494 HM753440 HM753383

Results

A review of the original descriptions of both P. rochebruni and P. crossei suggested that Mabille (1887a) and Dautzenberg and d’Hamonville (1887) described shells of the same species from Tonkin (Figure 1). Authors of both species provided nearly identical data for the size and shape of the shell, aperture, apex, and sutures, and the number of whorls (Table 2). Mabille (1887a) did not provide information on the color of P. rochebruni, but did note the interior shoulder of the peristome. Dautzenberg and d’Hamonville (1887a) gave the color of P. crossei as reddish-brown, did not mention the shouldered peristome, but did note the triangular breathing device. The illustration of P. rochebruni in Mabille (1887b) clearly shows the breathing triangle, though the shouldered peristome is not immediately apparent in the illustrated P. crossei shell (Dautzenberg and d’Hamonville 1887). No mention is made in either description of any small orange shells.

Figure 1.

Original illustrations and type material of Vietnamese Pollicaria. A. Pollicaria crossei from Dautzenberg and d’Hamonville (1887). B. P. rochebruni from Mabille (1887b). No figure was provided in Mabille (1887a). C. P. rochebruni, lectotype MNHN 21305. D. P. crossei, lectotype MNHN 21304. Lectotype images from Kongim et al. (2013).

Morphological character comparison taken from the original descriptions of Pollicaria rochebruni and P. crossei.

P. rochebruni P. crossei
Height 39 mm 39 mm
Diameter 21 mm 20 mm
Color n/a Reddish-brown
Peristome Thick, upturned, with a channel in the upper portion of the lip White, circular, thickened, with a triangular air space at the lip.
Whorls 6.5 to 7 convex, flattened 7 convex, flattened on the upper part
Aperture Circular Circular
Shell Ovate-pupiform, striate, and distorted Pupiform, striate, and distorted
Sutures Impressed Linear and impressed
Apex Obtuse Obtuse

A total of 87 museum specimens (Figure 2) was examined and an additional 44 specimens were collected by PMH and DVT. Many shells were weathered and slightly pitted, and most were light tan to medium brown in color. Of the 131 total specimens, 124 possessed a shoulder inside the peristome and seven did not. Using the key to Pollicaria in Kongim et al. (2013:25) we were able to identify 12 specimens to species level: three P. rochebruni, two P. crossei, and seven P. mouhoti. Seventeen specimens had a peristome with the interior shoulder, but were between 35 and 40 mm in height and excluded by the key. The remaining 119 specimens also had an interiorly shouldered peristome, but had shell size and coloration combinations different than those given in the key. Using the table of comparative characters given later in Kongim et al. (2013:28), we identified 43 P. rochebruni, two P. crossei, and seven P. mouhoti from the same set of 131 specimens. The remaining shells did not fit any combination of characters given in the table. The seven putative P. mouhoti specimens more closely resembled the specimens of P. myersii figured in Kongim et al. (2013:27) than the lectotype of P. mouhoti figured therein.

Figure 2.

Vietnamese Pollicaria from museum collections. A and B. FLMNH 130267, Pollicaria rochebruni, Tonkin Province, 36.9 mm and 34.4 mm respectively. C. FLMNH 164622 (in part), P. cf. crossei sensu Kongim et al. (2013), Thất Khê, Tonkin Province. 28.5 mm. Labeled as P. rochebruni. D. FLMNH 164621 (in part), P. cf. crossei sensu Kongim et al. (2013), Pak-Kha, Tonkin Province, 24.6 mm. Labeled as P. mouhoti. E and F. FLMNH 164620, P. mouhoti, Gia Phu, Tonkin Province, 32.5 mm and 30.9 mm respectively.

Pollicaria specimens are advertised for sale at five websites: eBay.com, yhshells.com, femorale.com, conchology.be, and topseashells.com. Taken together, these specimens suggest that the known distribution of Pollicaria species should be expanded to include Guangxi autonomous region and Yunnan province in southern China. These two regions are adjacent to the northern borders of Vietnam, Laos, and Myanmar. Shells from these two regions were identified by their sellers as P. crossei, P. gravida, and P. rochebruni. All but two Chinese specimens possessed the interiorly shouldered perisotome; the other two possessed the flared lip and no shoulder seen in P. mouhoti and P. myersii. Shell sizes varied up to 45 mm in length, and shell colors varied from light tan through orange, reddish brown, dark brown, and dark purple. Vietnamese Pollicaria specimens varied similarly in color and size to the Chinese samples, and all possessed the interior shoulder in the peristome. These specimens were labelled as P. crossei and P. rochebruni.

DNA sequences from our putative P. rochebruni and P. crossei specimens (Figure 3) were identical for all three genes. Alignment lengths for each gene were 566 positions for 16S, 430 for 18S, and 838 for 28S. Our phylogenetic analysis produced a single tree (log-likelihood -17304.7519) that recovered a monophyletic, well-supported Pupinidae sister to Cochlostomatidae. Pollicaria was resolved as sister to a clade of all other pupinids (Figure 4).

Figure 3.

Pollicaria specimens sequenced in this study. A. CM 155302, orange phenotype (cf. P. crossei sensu Kongim et al. [2013]), 38.6 mm. B. CM 155307, red-brown phenotype (cf. P. rochebruni), 24.7 mm.

Figure 4.

Phylogenetic tree (log likelihood= -17304.7519) based on three ribosomal genes (mt 16S, nuclear 18S and 28S) showing Pollicaria as sister to all other pupinid taxa. Values at branches are bootstrap values based on 10,000 ultrafast replicates.

Discussion

Based on museum, online, and our own data, we believe that at least two, and possibly three, species of Pollicaria occur or have historically occurred in Vietnam. We consider the first, P. rochebruni, to comprise both P. rochebruni sensu stricto and P. crossei pre-Kongin et al. (2013). We treat P. rochebruni and P. crossei as synonyms based on the similarity of their original descriptions, the natural variation seen among shells of both species, and preliminary molecular evidence. The name P. rochebruni (publication date 14 May 1887) has priority over P. crossei (1 July 1887) and should be applied from hereon. We follow Kongim et al. (2013) in keeping P. rochebruni separate from P. gravida, given the lack of specimens of Pollicaria with an internally shouldered peristome from between Burma and Vietnam. This implies that the two species are geographically separate; based on the underlying geology, those regions separated approximately 40 million years ago (Yin 2010). However, since museum records only document presence not absence, future collections may suggest a continuous distribution. Additional karyotype and sequence analysis is needed to confirm or refute the separation between topotypic P. gravida and P. rochebruni. The revised distribution of P. rochebruni now includes Vietnam south to Đà Nẵng, with a possibility of stretching northeast into southern China (Figure 5).

Figure 5.

Revised distribution map for North Vietnamese Pollicaria species. Pollicaria rochebruni is present at all sites shown. Black dots indicate the presence of P. mouhoti, while gray dots indicate the presence of the putative new species of Kongim et al. (2013). Coordinates for localities taken from museum data were estimated from historical sources.

We identified the second Vietnamese Pollicaria species as P. mouhoti, based on Solem’s (1966) identifying collections of shells with peristomes lacking an internal shoulder and possessing a flared and partially reflexed lip to that species. We identified seven museum specimens which keyed out to P. mouhoti based on Kongim et al. (2013). Shells of P. mouhoti were collected by Solem (1966) in Vat Son, and we found additional museum specimens from Thái Nguyên, Gia Phu, Muong, and Bắc Kạn. Internet records suggest similar shells can be found in southern China, but it is unknown if they are the same species. The distribution of P. mouhoti in Vietnam appears restricted to isolated areas in the north.

A possible third Vietnamese Pollicaria species is based on karyotype differences that Kongim et al. (2010) uncovered in nominal P. gravida from Vietnam. Kongim et al. (2013) assigned their two P. gravida karyoptyes to P. rochebruni and P. crossei, the former having a large brown shell and the latter a small orange shell. We did not generate chromosome spreads for any individuals, but based on the figures in Kongim et al. (2010) we find the karyotypes between the brown and orange individuals to be equivocal. We also feel the radula differences listed in Kongim et al. (2013) are non-diagnostic characters. Kongim et al. (2010) believed that their small, orange-shelled snail was the result of sympatric speciation due to chromosomal evolution as outlined in King (1993). This hypothesis is consistent with studies of similar patterns of intra- and interspecific karyotype variation seen elsewhere (e.g. Ayala and Coluzzi 2005). Whereas authors have provided possible selective pressures that may accompany the karyotypic divergence (e.g. elevation and temperature), there is insufficient data available to pose any similar hypothesis for this Pollicaria species. Given our synonymizing of P. crossei with P. rochebruni, if the individuals with the unique karyotype represent a new species it will require a new name. The known distribution of this possible taxon is limited to Cúc Phương National Park and Hữu Liên nature preserve (Kongim et al. 2013).

Our preliminary molecular evidence suggests that shell color and size may not be reliable for consistent species identification in Vietnamese Pollicaria. Sequences from one small, reddish-brown shelled snail (cf. P. rochebruni) and one large, orange-shelled snail (cf. P. crossei) were identical at three genetic loci. Our orange-shelled snail was larger than the nominal P. crossei in Kongim et al. (2013), and was collected alongside similarly-sized individuals with brownish and reddish shells. We feel both of our sequenced specimens represent P. rochebruni, supporting our belief that shell color in Pollicaria species can vary greatly. This contrasts with Kongim et al. (2013), who felt that shell color was diagnostic for many species.

Despite our best efforts and those of Kongim et al. (2013) to untangle the taxonomy of Pollicaria, we recognize the need for more work on the genus. Karyotypes of topotypic P. gravida remain unknown so no comparisons to the Vietnamese and other taxa can be made. Additional field work in southeastern Asia and southern China is needed to determine the true ranges of each species.

Systematic accounts

Family Pupinidae

Pollicaria Gould, 1856

Type species

Megalostoma gravidum Benson, 1856 (=Cyclostoma pollex Gould, 1856), designated by Pain (1974).

Pollicaria rochebruni (Mabille, 1887)

Hybocystis rochebruni Mabille 1887a:12; Mabille 1887b: 138, pl. 2, figs 12 and 13; Dautzenberg and Fischer 1905:171

Pollicaria rochebruni – Kobelt 1902: 290; Kongim et al. 2013: 35, figs 5D and 5E

Hybocystis crossei Dautzenberg and d’Hamonville 1887: 220, pl. 8, fig. 4; Kobelt and Möllendorf 1899: 137; Kobelt 1902: 290; Dautzenberg and Fischer 1905:171

Pollicaria crosseiKongim et al. 2013: 37, fig. 5F

Hybocystis gravidaPain 1974: 174.

Pollicaria gravidaKongim et al. 2010: 127 (“big brown shell”)

Type Designation and locality

Lectotype MNHN 21305, Tonkin. Paralectotypes MNHN 25855, Tonkin (Kongim et al. 2013).

Material examined

All material from Vietnam / Tonkin Province. The number in parentheses is the number of shells from each lot assigned to the species. Locality names have been corrected wherever possible. – CM 155301, south of QL279, Thẩm Dương, Văn Bàn District, Lao Cai (7); CM 155302, Vườn quốc gia Cúc Phương, Lạc Sơn District, Hòa Bình (3); CM 155303, south of QL279, Thẩm Dương, Văn Bàn District, Lao Cai (7); CM 155304, limestone mountain at bridge into Tan Moui, near intersection of QL279 and DT234B, southwest of Chi Lăng, Lạng Sơn (6); CM 155305, ca. 60 m north of the intersection of QL1A and DT234B, Chi Lăng, Lạng Sơn (6); CM 155306, limestone mountain off QL279 at H9/155 road marker, ca. 1.1 km southwest of Dong Mo and 0.9 km southwest of Chi Lăng, Lạng Sơn (1); CM 155307, Công An huyện Cao Phong at QL6, Cao Phong, Hòa Bình (15); FLMNH 130259, Thất Khê (4); FLMNH 130265, Phu Ly (3); FLMNH 130623, Thái Nguyên (1); FLMNH 130258, Bắc Kạn (3); FLMNH 130261, Thái Nguyên (3); FLMNH 130262, Thái Nguyên (3); FLMNH 130624, Phi Mi (1); FLMNH 130260, Thái Nguyên (2); FLMNH 130268 (1); FLMNH 243794, Thái Nguyên (2); FLMNH 271764, Ninh Bình Province, Cúc Phương National Park, path to fairy cave, primary forest (1); FLMNH 164619, Thái Nguyên (2); FLMNH 164620, Gia Phu (2); FLMNH 164621, Pak-Kha (2); FLMNH 164622, Thất Khê (3); FLMNH 164623, Chợ Rã (4); FLMNH 130267 (2); FLMNH 242525 (2); FLMNH 192609, Thất Khê (6); FLMNH 130266 (1); MCZ 180001, vicinity of Lake Ba Bể (2); MCZ 180002 (2); MCZ 180003, Thất Khê (2); MCZ 180004, vicinity of Lake Ba Bể (3); MCZ 180005, Thái Nguyên (1); MCZ 180006, Thái Nguyên (4); MCZ 180007, Pak-Kha (4); MCZ 180008, Bảo Lạc (2); MCZ 180009, Pak-Kha (1); MCZ 197272, Pak-Kha (4); MCZ 380546 (1); USNM 207972, Lào Cai (1); USNM 207973, Lào Cai (1); USNM 207974, Chợ Rã (1); USNM 207975, Bắc Kạn (1); USNM 207976, Chợ Rã (1); USNM 207977, Chợ Rã (1); USNM 207978, Muong (1); USNM 207979, Muong (1); USNM 207980, Vân Sơn (1); USNM 207981, Vân Sơn (1); USNM 220045, Ba Bể (3); USNM 335963, Bắc Kạn (2).

Literature records

(not examined). All from Vietnam, taken from Kongim et al. (2013). CUMZ 1523, Phong Na National Park, Quảng Bình; CUMZ 1532, Cúc Phương National Park, Ninh Bình; CUMZ 1539, Phong Na National Park, Quảng Bình; CUMZ 1552, Phong Na National Park, Quảng Bình; CUMZ 1556, Bạch Mã National Park; CUMZ 1568, Phong Na National Park, Quảng Bình; CUMZ 1568, Cúc Phương National Park, Ninh Bình; CUMZ 1573, Cúc Phương National Park, Ninh Bình; CUMZ 1587, Cúc Phương National Park, Ninh Bình; CUMZ 1589, Khe Sen, Đà Nẵng; CUMZ 1594, Hữu Liên Nature preserve; MNHN 21304, Than Moi, Tonkin; RBINS 525390, Than Moi, Tonkin.

Description

Pupoid shell, to 45 mm length and 20 mm diameter, color varying from tan to orange, reddish-brown, and dark brown, possibly dark purple. Old specimens are often finely pitted. Whorls 5-7, transverse growth lines present, sutures linear and slightly impressed, apex obtuse and occasionally distorted to the left (assuming standard anatomical position), spire short. Penultimate body whorl may appear inflated relative to whorls on either side. Aperture circular with a right posterior triangular breathing structure. Peristome thickened, white to shell colored, with a thin parietal declining shoulder inside; umbilicus narrow. Operculum concentric, thick, and calcareous.

Radula with teeth in a 2-1-1-1-2 arrangement, based on the figure in Kongim et al. (2013: Figure 6E). Central tooth with three cusps, the middle one longer that the others. Lateral teeth with one large cusp and one smaller cusp on the central side. Marginals with one large central cusp flanked by one smaller cusp on each time. Kongim et al. (2013) described the radula as having more cusps per tooth than illustrated.

Distribution

Northern Vietnam south to Đà Nẵng (Figure 5). Possibly in Guangxi autonomous region and Yunnan Province, China.

Discussion

By synonymizing P. rochebruni and P. crossei, we suggest that all Pollicaria specimens from Vietnam that possess an interiorly shouldered peristome are a single species, excluding some smaller (< 35 mm) individuals with bright orange shells. We found live specimens of P. rochebruni at the bases of and in the valleys between karst outcrops in northern Vietnam. Reports from local farmers indicated that snails are more abundant during the spring rains, when native residents eat them as a delicacy. Some Chinese shells found for sale on the Internet are consistent morphologically with P. rochebruni but may represent a separate species.

Acknowledgements

RLM was supported by Faculty Research Support Funds through UHCL. PMH was supported in part by the UA Research Grants Committee, and a UA College Academy of Research, Scholarship, and Creativity award. Images of original figures (P. rochebruni and P. crossei) were downloaded from Biodiversity Heritage Library and are in the public domain. Images in figure 1 are reproduced from Kongim et al. (2013) under the terms of the Creative Commons Attribution License 3.0.

References

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