The genus Cerithidea Swainson, 1840 (Gastropoda: Potamididae) in the Indo-West Pacific region Author Reid, David G. text Zootaxa 2014 3775 1 1 65 journal article 36884 10.11646/zootaxa.3775.1.1 c2c6d40e-39c0-477c-9bc2-8eae0c3dd816 1175-5326 285731 D9FF6080-0316-4433-ABB8-7D6D6F2BF24B Cerithidea tonkiniana Mabille, 1887 ( Figures 2 F, 13N–Y, 14A) Cerithidea tonkiniana Mabille, 1887 : 158 –159 ( Tonkin [N Vietnam ]; 3 syntypes MNHN 25690, Fig. 13 Q ]. Reid et al ., 2013 : figs 1 (phylogeny), 2 (map). Potamides (Cerithidea ? ) tonkinianus — Fischer, 1891 : 163 . Potamides (Cerithidea) tonkinianus — Fischer & Dautzenberg, 1904 : 416 . Cerithidea (Cerithidea) sinensis var. tonkiniana — Dautzenberg & Fischer, 1905 : 137 –138. Cerithidea ornata — Kuroda & Habe, 1952 : 44 . Habe & Kosuge, 1967 : 34 , pl. 13, fig. 17. Habe, 1968 : 38 , pl. 11, fig. 24. Higo, 1973 : 59 . Wells, 1985 : 145 , pl. 1 G. Choe, 1992 : 310 –311, pl. 65, fig. 103a, b. Higo & Goto, 1993 : 105 . Higo, Callomon & Goto, 1999 : 87 . Lee & Min, 2002 : 103 . Ma, 2004 : 38 , pl. 016A (not 016C). Kojima et al ., 2006 : 525 –535. Reid et al ., 2008 : 680 –699 (in part, includes C. balteata ). Zhang, 2008 : 61 , fig. (All not Sowerby, 1855 ). Cerithidea (Cerithidea) ornata — Oyama, 1959 : figs 7, 14. Fukuda, 1996 : 21 , pl. 3, fig. 4. Fukuda, 2000 : 106 –110, 135, fig. 5.4b (shell), fig. 5.5b (living animal). Hasegawa, 2000 : 133 , pl. 66, fig. 2. Hong, Choi & Tsutsumi, 2010 : 258 , fig. 4b. Fukuda & Kimura, 2012: 29, textfigs a (living animal), b, c (shell). (All not Sowerby, 1855 ). Cerithidea morchii — Lee & Min, 2002 : 103 (not Sowerby, 1855 ). Min et al ., 2004 : 129 , fig. 220 (not Sowerby, 1855 ). Cerithidea (Cerithidea) weyersi — Thach, 2007 : 60 , pl. 9, figs 173, 181 (not Dautzenberg, 1899 ). Cerithidea sinensis — Li & Xu, 2013 : 452 –453, figs 8 (shell), 9 (radula) (not Philippi, 1848 ). Taxonomic history. The original description by Mabille (1887) was rather vague and the species was not illustrated. For these reasons the name has not been used since the early twentieth century, until recently resurrected by Reid et al . (2013) . Dautzenberg & Fischer (1905) considered it to be a variety of C. sinensis . The species has frequently been described and figured in the recent literature from Japan , China , Korea and Vietnam , although always misidentified. It has usually been named C. ornata (a synonym of the superficially similar C. balteata ), following the identification by early Japanese workers ( Kuroda & Habe 1952 ; Oyama 1959 ). Diagnosis. Shell: periphery rounded or slightly angled; aperture thickened and flared; 11–25 rounded axial ribs on penultimate whorl, 4–11 ribs after ventrolateral varix; ventrolateral varix a strong rib at 180–220(250)°; 5 weak spiral ridges above periphery (especially on spire if not eroded); banded or lined pattern. S Japan , S Korea , S China , N Vietnam . COI GenBank AM932766 , AM932767 , HE680220 –680224. Material examined. 15 lots. Shell ( Fig. 13 N–Y): H = 23.0– 38.1 mm . Shape elongated conical (H/B = 2.04–2.31, SH = 2.59–2.99); decollate, 6–7 whorls remaining; spire whorls moderately rounded, suture distinct; spire profile mostly straight, but concave in apical whorls that are lost in adults and becoming convex at final whorl; periphery rounded to slightly angled; thin to moderate thickness. Adult lip flared, slightly thickened; rarely a previous lip on final whorl; apertural margin slightly sinuous in side view; moderate anterior projection adjacent to canal. Sculpture on spire of straight to slightly opisthocline axial ribs, becoming slightly curved (opisthocyrt) on final 1–2 whorls, ribs prominent, rounded, interspaces1–1.5 times width of ribs, 11–25 ribs on penultimate whorl; axial ribs becoming more distant but usually remaining strong after ventrolateral varix, numbering 4–11; spiral sculpture only visible on spire whorls if well preserved, 5 weak spiral ridges on axial ribs only, plus strong outermost basal cord usually visible in suture; traces of 5 spiral ridges sometimes present above periphery on final whorl, but only in interspaces between axial ribs; base with 9–13 striae, of which outermost is largest and may form a weak peripheral keel, below which axial ribs do not continue. Ventrolateral varix a thickened rib at 180–220(250)°. Surface with fine spiral microstriae on periostracum; ribs dull when worn. Colour: pale brown with dark spiral lines and bands; basic pattern is brown band on base, a line just below periphery and 4 bands at and above periphery, but these may be lost or fused; even in darkest shells there is a pale band at shoulder and below periphery; bands show through in aperture. Animal ( Fig. 2 F): Head grey with cream spots; anterior half of snout blackish with yellow spots arranged in 2–3 transverse bands; tentacles grey with black rings and black base; sides of foot blackish; sole of foot grey; mantle pale grey (ethanol-preserved specimens similar). Range ( Fig. 14A ): S Japan , S Korea , S China , Vietnam . Records: Japan : Tosa Prov., Shikoku ( ANSP 191129 ); Ukidono-kobashi, Yorimo R., Touruta-shinden, Usa, Oita Pref., Kyushu ( NHMUK 20070383); Hikawa R., Yatsushiro-gun, Kumamoto Pref., Kyushu ( NHMUK 20070378). S Korea : Suncheon Bay ( Hong, Choi & Tsutsumi 2010 ). China : Zhejiang to Guangxi (Qi 2004); Tolo Harbour, Hong Kong ( NHMUK 20130261; USNM 858380). Vietnam : Quikim Brackish Water Research Station, Hai Phong ( NHMUK 20130260); Ha Long Bay ( RMNH ); Long Hai ( Thach 2007, as C. weyersi ). Habitat and ecology. On mangrove trunks and branches and on mud and stones under mangroves ( Hong Kong ); intertidal mudflat with Phragmites reeds at river mouth ( Japan ); brackish salt marsh at edge of shrimp ponds (northern Vietnam ). In Hong Kong , Wells (1985) reported it from mangroves at upper tidal levels, attached by mucus to trees, and described it as rare, except at Ting Kok. McMahon (1985) likewise observed that it was restricted to the upper parts of the mangrove belt, above the mean tide mark; it was most common at the landward edge and found above 1.0 m on trunks and branches, attached by mucus when dry. Hong et al . (2010) found it on mud flats among Suaeda plants in Korea . Remarks. The shell of this species closely resembles that of C. balteata from the Philippines , Indonesia and New Guinea , and it has usually been identified as ‘ C. ornata ’ (= C. balteata ). Molecular data show that the two are distinct and belong to separate clades ( Reid et al . 2008 , 2013 ). The most useful characters for separation are the broader shape of C. tonkiniana with stronger and more numerous (4–11, cf. 0–6 in C. balteata ) axial ribs continuing after the ventrolateral varix; the frequent position of the ventrolateral varix at about 180° (usually about 270° in C. balteata ); and the weak spiral ribs on the spire whorls (absent in C. balteata ). However, the great variability of C. balteata across its wide range and the often eroded condition of the shells make morphological diagnosis difficult. Cerithidea tonkiniana is sympatric over much of its range in China and northern Vietnam with C. sinensis , with a somewhat similar shell (see Remarks on C. sinensis for discrimination). Its range also overlaps broadly with that of another potamidid, Cerithideopsis largillierti . Although superficially similar, the latter species is not decollate, lacks a distinct ventrolateral varix, the aperture is sinuous in side view and is not flared, the periostracum is thicker with strong slightly bristly striae, the whorls are more rounded and the axial ribs are often more numerous (20–26 on penultimate whorl); the living animal is black with yellow snout tip and tentacle bases, and does not climb onto vegetation. In molecular analyses C. tonkiniana forms a clade with C. moerchii ( Reid et al ., 2008 , 2013 ; Fig. 1 ) although the sister species of the latter is probably the unsampled C. rhizophorarum (see Remarks on that species). Cerithidea tonkiniana and C. moerchii are broadly sympatric from southern Japan to Vietnam , but are readily distinguished by the much stronger spiral ridges of C. moerchii ( Fig. 15 J–AA). The larval development has not been explicitly reported, but Kojima et al. (2006) claimed a ‘planktotrophic stage’ of 12–20 days (quoting Kimura et al . 2002 , who mentioned planktonic larvae in ‘ C. ornata ’, and unpublished work). This species is listed as ‘endangered’ in Japan ( Fukuda 1996 ; Fukuda & Kimura 2012) as a consequence of threats to its habitat and its narrow range in the country.