identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
E52387E6B42FFFCDFF6FF933FB15FBCC.text	E52387E6B42FFFCDFF6FF933FB15FBCC.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Cyclotus Swainson 1840	<div><p>Genus Cyclotus Swainson, 1840</p><p>Cyclostoma (Cyclotus) Swainson 1840: 336 .</p><p>Siphonocyclus Möllendorff 1900: 135, 136. (type species: Pterocyclos tener Menke, 1856, subsequent designation by Kobelt, 1911: 813)</p><p>Tubicyclotus Habe 1965: 119 . (type species: Opisthoporus setosus Möllendorff, 1894 by original designation) (synonymized by Maassen, 2001)</p><p>Type species. It is frequently cited that the type species of Cyclotus is Cyclotus variegatus Swainson, 1840 (fixed subsequently by Kobelt 1902). However, Bouchet et al. (2017) showed that Gray (1847) designated a type species for Cyclotus earlier. The nomenclatural situation is very complex, and here we do not mention all details (see Bouchet et al. 2017). Cyclostoma planorbula Lamarck, 1816 is also a type species of Crossopoma Martens, 1891 . Bouchet et al. (2017) mentioned that stability of nomenclature will be best achieved by declaring Cyclostoma planorbulum Lamarck, 1816 to be an available name (despite its homonymy with Cyclostoma planorbulum Lamarck, 1804 from the French Eocene) and Cyclophorus variegatus Swainson, 1840 to be the type species of Cyclotus, and an application will be submitted to the ICZN to that effect. However, no action on this regard has been done since. Nevertheless, here we refer to Cyclophorus variegatus Swainson, 1840 as the type species of Cyclotus .</p><p>Remarks. The Ba Den specimens of Cyclotus simonianus agree with the diagnosis of the genus Opisthoporus Benson in L. Pfeiffer, 1851 given by Do et al. (2020). However, that paper considers only the Vietnamese members of Opisthoporus, which differ considerably from the type species of Opisthoporus ( Cyclostoma taylorianum L. Pfeiffer, 1851). Namely, C. taylorianum from Borneo (synonym of Opisthoporus biciliatus (Mousson, 1849), see Kobelt 1902; Tongkerd et al. 2023) has alternating lighter and darker, zigzag-like stripes on its shell, has long hairs standing in two spiral striae, its inner and outer peristomes are clearly distinct, has a strongly expanded outer peristome, and its breathing tube is situated ca. 1/8 whorl from the peristome (Marzuki et al. 2021). In contrast, the Vietnamese species figured by Do et al. (2020) ( Opisthoporus beddomei Dautzenberg &amp; Fischer, 1908, Opisthoporus lubricus Dautzenberg &amp; Fischer, 1908 and Opisthoporus thuathienhuensis D. S. Do, T. C. Bui &amp; V. N. Do, 2020) have unicoloured, yellowish ochre shells, the inner and outer peristomes are not clearly separated, the outer peristome is not particularly expanded, and lastly, the breathing tube opens just behind the peristome.</p><p>As Opisthoporus simonianus Heude, 1886 clusters with together with Taiwanese Cyclotus species in the COI tree, and agrees with them in most shell characters except for the presence of a breathing tube. Therefore, we classify O. simonianus in the genus Cyclotus . We note however, that the type species of Cyclotus ( C. variegatus, see also under Type species) is different from Taiwanese Cyclotus and Cyclotus simonianus and the Taiwanese Cyclotus species by having a strongly expanded outer peristome. Moreover, it was described from Palawan (more precisely, it was described without a type locality, but was reported from the Philippines, see Möllendorff, 1887, and the syntypes [NHMUK 1893.6.7.34–35] are from Palawan). We note that C. variegatus was subsequently reported from the Sulu Archipelago (Smith 1894) and Hainan Island of China (Yen 1939), and it is highly unlikely that C. variegatus would occur on all of those localities, although no revision has been carried out recently.</p></div>	https://treatment.plazi.org/id/E52387E6B42FFFCDFF6FF933FB15FBCC	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Tran, Thinh Gia;Bui, Chinh Thi;Vu, Long;Le, Dung Kim Thi;Ho, Huy Nhat Van;Páll-Gergely, Barna	Tran, Thinh Gia, Bui, Chinh Thi, Vu, Long, Le, Dung Kim Thi, Ho, Huy Nhat Van, Páll-Gergely, Barna (2026): Rediscovery and redescription of an endemic land snail from Vietnam: Cyclotus simonianus (Heude, 1886) with its phylogenetic position. Zootaxa 5785 (1): 134-151, DOI: 10.11646/zootaxa.5785.1.5, URL: https://doi.org/10.11646/zootaxa.5785.1.5
E52387E6B42CFFC6FF6FFB36FE36FF2D.text	E52387E6B42CFFC6FF6FFB36FE36FF2D.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Cyclotus simonianus (Heude 1886)	<div><p>Cyclotus simonianus (Heude, 1886)</p><p>Figs 2–7A; Table 3</p><p>Opisthoporus simonianus Heude, 1886: 209</p><p>Opisthoporus simonianus – Heude, 1890: 129, pl. XXXVIII, fig. 4, pl. XLII, fig. 14a.</p><p>Rhiostoma simonianum –Fisher, 1891: 103.</p><p>Opisthoporus simonianus – Möllendorff, 1892: 18.</p><p>Cyclotus (Siphonocyclus) simonianus – Möllendorff, 1900: 137.</p><p>Cyclotus (Siphonocyclus) simonianus – Kobelt, 1902: 211.</p><p>Rhiostoma tieni Thach, 2024: 8, figs. 1–3, new synonym.</p><p>Type localities. “Tay-ninh, Cochinchinae” ( C. simonianus); “Bà Ðen Mountain, Thạnh Tân Commune, Tây Ninh Province, Southern Vietnam ” ( R. tieni).</p><p>Type material. Cyclotus simonianus (Heude, 1886): 1 syntype (empty shell), Tay-ninh, Cochinchinae, MCZ 167042; Rhiostoma tieni Thach, 2024: 1 holotype (empty shell), Ba Den Mountain, Thanh Tan Commune (now is Binh Minh Ward), Tay Ninh Province, Vietnam, MNHN-IM-2000-39359.</p><p>Material examined. CBESMZ 01 (female), CBESMZ 04 (male), CBESMZ 05 (juvenile), CBESMZ 06 – 12 (empty shells), from <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=106.16854&amp;materialsCitation.latitude=11.388629" title="Search Plazi for locations around (long 106.16854/lat 11.388629)">Ba Den Mountain</a>, Thanh Tan Commune (now is Binh Minh Ward), Tay Ninh Province, Vietnam (11.365556°N, 106.165278°E; altitude 80 m a.s.l.), collected on 07 January 2025 by Thinh Gia Tran; CBESMZ 02 (male), CBESMZ 03 (female), from Ba Den Mountain, Thanh Tan Commune (now is Binh Minh Ward), Tay Ninh Province, Vietnam (11.388629°N, 106.168540°E; altitude 731 m a.s.l.), collected on 08 January 2025 by Thinh Gia Tran .</p><p>Revised description. Shell thick, medium-sized (height: 9.65–11.9 mm; width: 21–24.65 mm; detached-whorl length: 7.8–13 mm; n = 10, except the juvenile specimen), flattened shape with a wide umbilicus (umbilicus width 32–35 % of shell width). Apex acute; spire slightly elevated to nearly flat. Whorls 4½–4¾, regularly expanded with the last whorl partially detached from the penultimate whorl. Suture deeply impressed. Shell surface bearing irregular spaced, radial growth lines: some are closed together, some are spaced apart with a maximum distance of 0.4 mm, and the frequency of these lines being close together increases towards the protoconch. The protoconch smooth, 1¼–1½ whorls. Shell color brownish background with reddish to brown growth lines. Periostracum thin, brownish with reddish hairs (maximum length 1.5 mm) reflexed backward on the growth lines around the shell, except protoconch and the first teleoconch whorl. Aperture oblique to shell axis in lateral view, circular, opening subventrally; lip thickened and slightly expanded, multilayered. The completely developed breathing tube small (1.5–3.0 mm), slender, curved, situated a little distance (0.6–1.35 mm) from the peristome.</p><p>Operculum circular in the adult, sub-cicular in juvenile (Fig. 4A–C). The operculum consists of two plates: a basal plate concave, brownish, smooth, glossy with an elevated central nipple; and an upper plate complexed, concave, superimposed on the basal one. The upper plate consists of an elevated central nipple in the center and calcified lamella coiled around the nipple in a spiral order (Fig. 4D). The lamellae stand perpendicular to the basal plate; their apical portions are thickened and expanded, and keeled with ridges on the surface. While lamellae coiling, the expanded top of lamella is overlapped anteriorly by the preceding lamella, while its posterior part overlaps the anterior part of the succeeding lamella. The space between lamellae whorls increases in size towards the last whorl (Fig. 4D); the basal surface of space is smooth in at least first five whorls and strongly keeled in older whorls (Fig. 4E). This spire comprised more than 10 whorls in adult specimens (Fig. 4A). On the lateral side of the operculum, the upper plate has a thick top section and ridges, which also form a row of small, uneven cells underneath, followed by a wide, recessed groove with a horizontal ridge, and finally the basal plate (Fig. 4B).</p><p>External features. Both females and males show blackish patches and mottles scattered on a whitish body on the dorsal and lateral sides (Figs. 6, 7A). Head with a pair of long cephalic tentacles (ct) always black, each containing a dark eyespot (es) at outer base. Anterior body short with genital groove on right side running downwards from anterior end of pallial cavity. Posterior body long; foot broad, white ventrally, with operculum attached dorsally of posterior body. The lung cavity (lc) has large vein and reticulated vessels. Ctenidium and osphradium absent. Mantle collar (mc) smooth. Columellar muscle (cm) white, broad and thickened. Heart (h) and kidney (kd) visible in the left side in both sexes.</p><p>The species is dioecious. Male (Fig. 6A) has both long conical external penis (p) on right side below tentacles and eye, and sperm groove (sg) passed along to tip of external penis; testis (te) with branched tubules, bright orange, located around 3 whorls from apex; vas deferens (vd) thin, connected between testis and prostate gland (pg). Female (Fig. 6B) shows only vaginal groove (vg) on right side; ovary (ov) yellow, with multilobulated glands embedded within brownish digestive gland, located around 2 whorls from apex; oviduct (od) thin, connected between ovary and uterus; bursa copulatrix (bc) about half of the length of uterus; uterus (ut) large, long, curved.</p><p>Notes. The juvenile specimen (BDS 05) differs from adult individuals in having the last whorl not detached from the penultimate whorl, lacking a breathing device, and possessing a unexpanded lip (Fig. 5A). Specimens BDS 08–09 exhibit a breathing device with an incomplete tube, in which the outer lip protrudes into a short, nearly closed tube, and the inner lip bears a deep incision (Figs. 5B, C). Specimen BDS 11 shows a complete breathing tube, with the outer lip protruding into a curved, closed tube, and the inner lip bearing a trace of a slit-like scar (Fig. 5D). In the remaining specimens, the slit-like scar is closed and instead represented by a hole (Figs. 5E, F). These ontogenetic differences in the breathing tube correspond to the observations of Tongkerd et al. (2023), who reported that breathing devices are incomplete and similar among multiple snorkel snail species at early developmental stages, but become clearly distinct in older specimens.</p><p>The development of the breathing device in C. simonianus likely begins with a notch-like structure, at which stage the last whorl becomes detached from the penultimate whorl. Subsequently, the outer lip thickens and elongates, forming a nearly closed tube with a narrow longitudinal groove (slit) along its length, while the inner lip develops a deep incision. Finally, in older individuals, the outer lip rolls to form a curved, cylindrical tube located just behind the thickened lip, and the inner lip bears a small hole.</p><p>Comparisons. C. simonianus presently differs from all species of Cyclotus Swainson, 1840 by having the breathing tube.</p><p>Moreover, this species shares several morphological traits with species of the genus Opisthoporus Benson in L. Pfeiffer, 1851. However, this Vietnamese endemic species differs from other Opisthoporus species by possessing a shell with reddish hairs covering the shell surface, except for the protoconch and the immediately adjacent teleoconch whorl. Excluding the presence of hair on shell surface, C. simonianus is similar to Opisthoporus battambangensis (Thach &amp; Huber, 2020), O. grohi (Thach, 2020), O. ngocngai (Thach &amp; Huber, 2018), O. ngocthachi (Huber, 2020), O. thorsengi (Thach, 2020), O. tener (Menke, 1856) . However, compared with O. battambangensis, the tube of C. simonianus is elevated obliquely from the plane of the dorsal surface, and its tip is curved downwards, while that of O. battambangensis is straight and not elevated from the dorsal surface. The latter species has a domed dorsal surface, which is nearly flat in C. simonianus . From O. grohi, C. simonianus differs by having the spire slightly elevated to nearly flattened (vs. low conical) and the last whorl partially detached from the penultimate whorl (vs. last whorl much more detached from the penultimate whorl). From O. thorsengi, it differs by having an elevated and curved breathing tube, while that of O. thorsengi is straight and points backwards. Opisthoporus tener is most similar species due to the dark ribs, although they lack hairs (characteristic for C. simonianus), and the spire of that species is slightly elevated, while C. simonianus is nearly flat. Cyclotus simonianus is similar in shell size, shape, and colour to O. ngocngai and O. ngocthachi . Both species were described based on a single shell, and the differences between the formation of their tube versus that of C. simonianus may be due to individual variation. Besides the lack of hairs in O. ngocngai and O. ngocthachi we are unable to find any useful characters to distinguish them from C. simonianus . Opisthoporus ngocngai and O. ngocthachi were described from the same district (Ninh Hoa District, Khanh Hoa Province), and their differences are best explained by intraspecific variability. Therefore, we treat Opisthoporus ngocthachi as a junior synonym of Opisthoporus ngocngai .</p><p>Remarks. Both Cyclotus simonianus (Heude, 1886) and Rhiostoma tieni Thach, 2024 share highly similar morphological characters including an orbicular, depressed shell with a wide umbilicus; a low to nearly flat spire; the last whorl partially detached from the penultimate whorl and descending; sculpture consists of irregularly spaced, inconspicuous growth lines; aperture circular with outer lip thick; breathing tube curved, located near the peristome; operculum round, bi-layered with the outer calcified layer thicker than the inner corneous layer. The only apparent difference between C. simonianus and R. tieni is the presence of reddish hairs on the shell surface. However, these hairs may be partially lost during the lifetime of the animal (Fig. 7A) and can be completely absent in long-dead shells (Fig. 3A). Moreover, the type localities of both taxa are from Tay Ninh Province, specifically Ba Den Mountain (Heude 1886; Thach 2024). Therefore, R. tieni is herein regarded as a junior subjective synonym of C. simonianus .</p><p>Distribution. Cyclotus simonianus (Heude, 1886) is currently known from Ba Den Mountain, Tay Ninh Province, southern Vietnam.</p></div>	https://treatment.plazi.org/id/E52387E6B42CFFC6FF6FFB36FE36FF2D	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Tran, Thinh Gia;Bui, Chinh Thi;Vu, Long;Le, Dung Kim Thi;Ho, Huy Nhat Van;Páll-Gergely, Barna	Tran, Thinh Gia, Bui, Chinh Thi, Vu, Long, Le, Dung Kim Thi, Ho, Huy Nhat Van, Páll-Gergely, Barna (2026): Rediscovery and redescription of an endemic land snail from Vietnam: Cyclotus simonianus (Heude, 1886) with its phylogenetic position. Zootaxa 5785 (1): 134-151, DOI: 10.11646/zootaxa.5785.1.5, URL: https://doi.org/10.11646/zootaxa.5785.1.5
