A new species of the genus Sinoennea Kobelt, 1904 (Pulmonata: Diapheridae) from Son La, Northwestern Vietnam Author Sang, Do Duc Author A new species of diapherid snail in the genus Sinoennea Kobelt, Do Van Nhuong Abstract. Author Province, is described from Son La Author Sinoennea copiaensis, Northwestern Vietnam. Author species, new Author Three apertural teeth are present, has a cylindrical glassy white shell sculptured with regularly spaced axial ribs. The parietal side of the peristome extends over part of the penultimate whorl. Author parietal, including one large Author basal, one Author This new species is similar to Sinoennea hippocrepis, one columellar. Author Bavay Author Dautzenberg Author whorls, but clearly differs from the latter by its larger shell with more Author This is the first species of genus Sinoennea to be reported from Son La province, an additional parietal tooth. text Raffles Bulletin of Zoology 2015 2015-10-23 63 490 493 journal article 10.5281/zenodo.5385957 2345-7600 5385957 583382B7-8A8D-4757-810E-7B455A8FBB57 Sinoennea copiaensis , new species ( Fig. 2A–E , Table 2 ) Material examined. Holotype : SORC 1130 ( Fig. 2 ). Measurements : shell height (SH) 13.56 mm , shell width (SW) 3.43 mm ; type locality: limestone karst in Copia Natural Reserve , Thuan Chau District , Son La Province , Northwestern Vietnam ( 21°25’25”N , 103°31’18”E , 1.246 m ) , Non-type material examined. Limestone forests in Quyet Thang , Co Noi , Mai Son , Son La ( 21°19’23”N ; 104°08’12”E ; 687 m ): SORC 1132 (5 shells), HNUEM (3 shells), coll. Phung Thi Ngoc & Do Duc Sang , 25 September 2013 ; Natural forest in Pa Kha , Long Luong , Van Ho , Son La ( 20°46’35”N ; 104°50’48”E ; 1.017 m ): SORC 1133 (12 shells), HNUEM (4 shells), coll. Vu Thu Phuong & Tran Thi Quynh , 5 August 2014 ; Limestone forests in Na Hoi , Chieng Khoang , Quynh Nhai , Son La ( 21°33’20”N ; 103°41’06”E ; 376 m ): SORC 1134 (8 shells), coll. Do Duc Sang , 16 September 2014 ; Limestone mountain in Nang Phai , Muong Bu , Muong La, Son La ( 21°28’26”N ; 103°01’34”E ; 721 m ): SORC 1135 (13 shells), coll. Do Duc Sang & Nguyen Thanh Lap , 27 October 2013 . Etymology. The specific epithet is derived from the type locality of this new species, the Copia Natural Reserve, Son La Province . Diagnosis. Shell high-spired, cylindrically pupiform with regular vertical ribs; glassy white and shiny. Parietal side of the peristome extended over a part of the penultimate whorl. Umbilicus narrow, hidden by the last part of the last whorl. Aperture oblique, quadrangular with rounded angles. Peristome smooth, continuous; lip thickened and expanded. Aperture with one large parietal tooth, which points towards the basal tooth. Description. Shell small to medium sized (SH 11.00– 14.60 mm , SW 3.10–4.02 mm , AH 3.10–3.40 mm , AW 2.51–2.90 Table 1. Known species of Sinoennea and their reported distribution from Vietnam.

Species name	Localities	Reference
S. atomaria	Hai Phong	Dautzenberg, 1893
S. calva	Hai Phong	Dautzenberg, 1893
S. copiaensis , new species	Son La	This study
S. hippocrepis	Phong Tho, Lai Chau	Bavay & Dautzenberg, 1912
S. macrodonta	Muong Kong, Muong Khuong, Lao Cai	Bavay & Dautzenberg, 1912
S. ovulum	That Khe, Trang Dinh, Lang Son	Bavay & Dautzenberg, 1912
S. plagiostoma	Ha Long Bay, Quang Ninh	Möllendorff, 1901

Table 2. Shell size variation of Sinoennea copiaensis , new species , shell height (SH), shell width (SW), aperture height (AH), aperture width (AW). Specimen collections and catalogue numbers are indicated in parentheses.

Locality (SORC nos.)	No. of Specimens	Ranges, Mean ± S.D. (mm) of the Shell SH SW AH AW
Copia, Thuan Chau, Son La (1130, 1131)	9	13.51–14.60 13.92 ± 0.54	3.42–4.02 3.55 ± 0.36	3.08–3.40 3.11 ± 0.18	2.66–2.90 2.85 ± 0.12
Co Noi, Mai Son, Son La (1132)	5	11.12–14.23 12.86 ± 0.79	3.31–3.60 3.42 ± 0.17	3.04–3.32 3.26 ± 0.14	2,69–2.89 2.83 ± 0.08
Long Luong, Van Ho, Son La (1133)	12	12.30–14.51 13.89 ± 0.61	3.32–3.89 3.60 ± 0.46	3.13–3.37 3.22 ± 0.12	2,72–2,83 2.78 ± 0.05
Muong Bu, Muong La, Son La (1135)	13	11.00–12.63 12.35 ± 0.32	3.10–3.64 3.22 ± 0.38	3.02–3.35 3.30 ± 0.15	2.51–2.78 2.62 ± 0.12
Chieng Khoang, Quynh Nhai, Son La (1134)	8	11.42–13.04 12.57 ± 0.40	3.22–3.91 3.51 ± 0.31	3.10–3.28 3.19 ± 0.09	2.61–2.74 2.65 ± 0.06

Table 3. Shell measurements and apertural teeth of Sinoennea spp. , shell height (SH), shell width (SW), number of whorls (W) (Reference: 1 = Dautzenberg (1893) ; 2 = Bavay & Dautzenberg (1912) ; 3 = Möllendorff (1901) ; 4 = Gredler (1885) ; 5 = Ouyang et al. (2012) ; 6 = Tanmuangpak et al. (2015) ; 7 = Dumrongrojwattana & Wongkamhaeng (2013) ; 8 = van Benthem Jutting (1961) .

Species name	W	SH (mm)	SW (mm)	Apertural teeth	Reference
Sinoennea species from Vietnam
S. atomaria	5	2.50	1.33	4: 1P, 1PL, 1B, 1C	1
S. calva	6	4.00	2.00	4: 1P, 1PL, 1B, 1C	1
S. copiaensis , new species	12–13	11.0–14.6	3.10–4.02	3: 1P, 0PL, 1B, 1C	This study
S. hippocrepis	10	8.00	2.50	2: 1P, 0PL, 0B, 1C	2
S. macrodonta	6.5	3.00	1.30	4: 1P, 2PL, 0B, 1C	2
S. ovulum	6.5	3.00	1.75	5: 1P, 2PL, 1B, 1C	2
S. plagiostoma	7.5	3.80	1.80	4: 1P, 1PL, 1B, 1C	3
Sinoennea species from China
S. fuchsi	8	5.00–5.50	2.00	2: 1P, 1PL, 0B, 0C	4
S. longtanensis	6	4.10–4.50	2.35–2.45	6: 1P, 2PL, 1B, 2C	5
Sinoennea species from Thailand
S. loeiensis	6.3	4.10–4.92	2.00–2.27	6: 1P, 2Pl, 1B, 2C	6
S. stunensis	8	3.53–3.61	1.37–1.41	4: 1P, 2PL, 0B, 1C	7
Sinoennea species from Malaysia
S. perakensis	6-7	4.00–4.60	1.90–2.10	4: 1P, 2PL, 0B, 1C	8
S. tiarella	7	3.00–3.50	1.50–1.70	4: 1P, 2PL, 0B, 1C	8

mm (see also Table 2 ), dextral, high-spired cylindrically pupiform, glassy, rather transparent and shiny ( Fig. 2A–D ). Apex obtuse, apical whorls smooth. Profile of shell whorls slightly convex, sculptured with closely set regular axial ribs numbering about 50–52 on the last whorl, 4 ribs or more partially obscured by the parietal callus; suture distinct and deep. Umbilical ribs, which are continuations connect of the external ribs of the last whorl are axially aligned and crowded, and extend into the umbilicus. Shell whorls numbering 12 to 13, and regularly increasing in height towards the last whorl. Umbilicus narrow, almost hidden by the last part of the last whorl and reflected outer lip. Aperture oblique, quadrangular with rounded angles. Peristome smooth, continuous, the leading edges thickened and expanded into a reflected lip ( Fig. 2E ). Aperture with one large tooth projecting from the middle of parietal side and pointing towards the basal tooth (B). The basal tooth (B) is set deeply in the aperture, and on the columellar side is one plate-like tooth (pC) that lies well inside the aperture ( Fig. 2E ). Distribution. The new species is known from several limestone karsts in Son La Province , Northwestern Vietnam : Mai Son District, Co Noi Commune; Thuan Chau District, Copia Natural Reserve; Muong La District, Muong Bu Commune; Quynh Nhai District, Chieng Khoang Commune; Van Ho District, Long Luong and Van Ho Commune ( Fig. 1 ). Remarks. Sinoennea copiaensis , new species , belongs to the group with cylindriform shells. The new species differs from congeners in Vietnam by its larger shell with more whorls. The shell shape of the new species is fairly similar to S. hippocrepis (of which a population was discovered at Lai Chau Province ), but S. copiaensis has an additional apertural tooth. Compared to other congeneric species from Vietnam ( S. atomaria , S. calva , S. macrodonta , S. ovulum , and S. plagiostoma ), China ( S. fuchsi and S. longtanensis ), Thailand ( S. loeiensis and S. stunensis ), and Malaysia ( S. perakensis and S. tiarella ), the shell of S. copiaensis possesses distinctly more whorls (12 to 13 whorls) than the others (see Table 3 ). Sinoennea copiaensis , new species , also differs from all other Sinoennea species known from China , Thailand and Malaysia by its larger shell. Sinoennea copiaensis , new species , shows little intraspecific conchological variation, except for shell size (see Table 2 ).