taxonID	type	description	language	source
03E987F40D5864380FC5151765B1FA0C.taxon	diagnosis	Diagnosis. Shell: moderately large (to 48 mm), delicate to solid, elongate, spire not decollate; sculpture of axial ribs, weakening on body whorl; 1 – 2 swollen varices may be present anywhere on body whorl (not routinely in a ventrolateral position) and others scattered over spire whorls; spiral ridges present on base, outermost 1 – 2 strongest with deep groove between, ridges absent or sometimes present above periphery; aperture circular, peristome sometimes flared and thickened in adult, planar or sinuous in side view, with weak anterior canal and slight posterior groove; columella straight or very slightly twisted, lacking folds; colour dark with peripheral white band and sometimes other spiral lines. Radula: rachidian tooth broad, square to pentagonal, with long central cusp and 2 denticles on each side; lateral tooth with long lateral extension; outer marginal with numerous small cusps and wide flange on outer side of basal shaft (Bright 1958: C. californica; Houbrick 1984: C. scalariformis).	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5864380FC5151765B1FA0C.taxon	discussion	Remarks. The comparative morphology of Cerithideopsis, Cerithidea and Cerithideopsilla has been described in detail by Houbrick (1984). Their respective monophyly was established in the molecular study by Reid et al. (2008), who also gave brief morphological diagnoses. A more detailed taxonomic account of Cerithidea was given by Reid (2014). The three western Atlantic species of Cerithideopsis are C. pliculosa, C. costata and C. scalariformis; these are relatively well known (Bequaert 1942; Abbott 1974). Traditionally, six species have been accepted on the American west coast (Keen 1971; Abbott 1974), but a recent molecular study (Miura et al. 2010) has suggested that this should be reduced to three: C. californica, C. montagnei and C. pulchra (C. B. Adams, 1852). Molecular discrimination of the American species is complicated by two cases of dispersal across the Panamanian Isthmus and subsequent introgression of mitochondrial haplotypes (Miura et al. 2012). The six Cerithideopsis species from the eastern Pacific and western Atlantic, and the three from the IWP described here, form two sister clades (Reid et al. 2008; Miura et al. 2010; Fig. 1). Several morphological characters are restricted to the IWP species, including the thick periostracum, the absence of a strongly thickened and flared peristome, and the yellow markings of the living animal — contrasting with the brown to black animals described by Bright (1958) in C. californica and Houbrick (1984) in C. scalariformis. The deeper phylogeny of the family (Reid et al. 2008) suggests that these are likely synapomorphies. Spawn and larval development have been reported in several species. The American Cerithideopsis species lay strings of eggs on mangrove roots, fallen leaves, algae or the mud surface (Houbrick 1984; Miura, Frankel & Torchin 2011). In the western Atlantic, C. scalariformis (Houbrick 1984) and C. pliculosa (Miura et al. 2011) hatch as late swimming-crawling veligers without a planktonic stage. In the eastern Pacific, C. californica in California either settles immediately upon hatching (Miura et al. 2011, quoting unpublished thesis by MacDonald 1967) or emerges at the crawling stage (Race 1981). However, in Panama C. californica shows a planktonic phase of up to 19 days (Miura et al. 2011). Development of the IWP species has not been recorded. The eastern Pacific and western Atlantic species of Cerithideopsis are all found at high tidal levels on sheltered sedimentary shores, often in estuaries and lagoons. They frequently shelter beneath mangroves and salt marsh plants, and all have been recorded to climb on vegetation at least occasionally, particularly to avoid submersion during high tide (Houbrick 1984; Cantera, Thomassin & Arnaud 1999; D. G. Reid unpublished observation of C. montagnei). However, they do not appear to display the regular climbing on mangroves and other emergent vegetation (involving avoidance of submergence and downward migration to feed) that is characteristic of Cerithidea species (Reid 2014). Climbing behaviour appears to have been independently derived in these two genera (Reid et al. 2008). Burrowing into the mud during cold spells has been recorded in C. californica (Race 1981). The IWP Cerithideopsis species have never been seen to climb on vegetation and appear to have no aversion to being submerged in shallow pools; C. australiensis is known to bury in the mud during neap tides (see below).	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5964360FC515C2629BF8E2.taxon	description	(Figures 2 A – E, 3 A, 4)	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5964360FC515C2629BF8E2.taxon	description	No type material of Cerithium largillierti has been traced (not present in MNHN, ZMB or SMF, which all contain some specimens of other species collected by Largilliert and / or described by Philippi). Philippi’s (1849) figure could serve as lectotype, but is not clearly drawn (Fig. 2 A) and an actual specimen is desirable. Therefore, a shell from Shanghai is here designated the neotype (NHMUK 20130431 / 1; Fig. 2 B). This shell is also one of the syntypes of C. fortunei A. Adams, 1855. To avoid any possible confusion, and to reinforce the synonymy, this specimen is also designated the lectotype of C. fortunei.	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5964360FC515C2629BF8E2.taxon	diagnosis	Diagnosis. Shell of medium size (to 36 mm), brown with two pale spiral bands above periphery; animal black with yellow tip to snout and tentacle bases; northern Vietnam, China, Korea, southern Japan; COI: AM 932788, AM 932789, HE 680618, HE 680623.	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5964360FC515C2629BF8E2.taxon	materials_examined	Material examined. 22 lots. Shell (Fig. 2 A – E): H = 23.9 – 35.9 mm. Shape elongated conical (H / B = 2.17 – 2.42, SH = 2.88 – 3.31); not routinely decollate, 9 – 11 whorls remaining in well preserved shells, but apex and protoconch always eroded. Spire whorls rounded, suture distinct; spire profile slightly convex, slightly concave towards apex; periphery rounded; relatively solid. Adult lip only slightly thickened, not flared; sometimes 1 – 2 previous lips on final whorl; apertural margin sinuous in side view; anterior canal a weak notch. Sculpture on spire of straight axial ribs, usually becoming curved (opisthocyrt) on last 2 – 3 whorls, ribs rounded, ribs and interspaces of similar width, 20 – 26 ribs on penultimate whorl, ribs becoming weaker and irregular on final whorl; 3 – 6 spiral cords on smallest apical whorls if well preserved, macroscopic spiral sculpture usually absent above periphery of larger whorls, sometimes 10 – 13 weak spiral elements visible between axial ribs on last 2 whorls; base with 8 – 9 cords, of which two at periphery are strong, with marked groove between, those towards columella becoming smaller. No ventrolateral varix, but 0 – 2 indistinct or prominently raised and rounded varices may be present at any point on last 2 whorls (Fig. 2 D). Surface with spiral microstriae on thick periostracum, short periostracal fringe or bristles remaining on larger striae (i. e. 10 – 13 striae macroscopically visible above periphery) if well preserved; shiny where periostracum worn away; surface often covered by thick black concretion, presumably of microscopic algae and sediment. Colour: brown, with pale band just above periphery and another at shoulder, often indistinct beneath periostracum; aperture brown with indistinct pale bands. Animal (Fig. 3 A): sides of foot black, paler towards margin; head grey, snout black, snout tip and tentacle bases yellow. Yellow coloration not preserved after storage in ethanol, but pattern visible as absence of black pigment (examined in two lots from Japan and Korea). Range: N Vietnam, China, Taiwan, S Korea, S Japan. Records: Vietnam: Quikim, Hai Phong (NHMUK; ZMSP). China: Tsim Bei Tsui, Hong Kong (NHMUK); Shanghai (NHMUK 20130431; ZMB; ANSP 275721); “ throughout Chinese coasts ” (Ma 2004: 38). Taiwan: Hsinchu (Yan Yu-Xiu; photo seen). S Korea: Daehang-ri, Byeonsan-myeon, Buan-gun, Jeollabuk-do (NHMUK 20070408); Suncheon Bay (Kamimura et al. 2010). Japan: Nagasaki (USNM 343900); Hikawa, Kumamoto Pref. (NHMUK); Onoda City, Yamaguchi Pref. (NHMUK); Tokyo (USNM 343901; Callomon & Goto 1999: quoting Okamoto 1995; Hasegawa 2000). Habitat and ecology. Mud flats at high tidal levels, on bare mud and among Phragmites reeds, often at river mouths; among saltmarsh vegetation (Korea) and at margins of brackish shrimp ponds (northern Vietnam).	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5964360FC515C2629BF8E2.taxon	discussion	Remarks. Over much of its range this species overlaps with two other potamidids, Cerithidea sinensis (Philippi) (China and northern Vietnam) and Cerithidea tonkiniana Mabille (Vietnam to southern Japan) (see Reid 2014 for detailed descriptions). The shells of these Cerithidea species are decollate as adults, the aperture is more strongly flared (and planar, not sinuous, in Cerithidea tonkiniana), the whorls less rounded, the axial ribs less numerous (14 – 19 in Cerithidea sinensis; 11 – 25 in Cerithidea tonkiniana), the periostracum is thin and the ventrolateral varix often present. The living animals also differ. That of Cerithidea sinensis has a cream head and foot with grey mottling, the tip of the snout is yellow with two transverse black bands just behind, and the tentacle yellow at the base with a black stripe across the eye. That of Cerithidea tonkiniana has a blackish foot, a grey head with cream spots, the anterior half of the snout is blackish with yellow spots arranged in 2 – 3 transverse bands, and the tentacle is grey with black rings and a black base. For comparison between the three species of Cerithideopsis in the Indo-West Pacific, see Remarks on C. australiensis below and Table 2. There have been two genetic studies of C. largillierti. Kojima et al. (2006) found two shared haplotypes of COI and no significant differences in frequencies between Japan and China. This was interpreted as suggesting recent migration between the two regions, either during the last glacial stage when there was a connection between Kyushu and Korea, or through a possible planktotrophic larva (larval development is unknown in this species). Kamimura et al. (2010) reported that COI haplotypes were of low diversity in Suncheon Bay, South Korea. The species inhabits threatened wetlands in southern Japan, where it has been listed as endangered (Fukuda 1996) or vulnerable (Fukuda & Kimura 2012).	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5564330FC514DB623BF9BC.taxon	description	(Figures 2 F – H, N, O, 3 B, 4)	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5564330FC514DB623BF9BC.taxon	etymology	Etymology. From its distribution, centred on the Malay Peninsula. Taxonomic history. The record of ‘ Cerithidea fortunei ’ from Mindoro by Casto de Elera (1896) could possibly apply to this species. Also from the Philippines, it has previously been identified and figured as C. largillierti (Lozouet 2008; Lozouet & Plaziat 2008).	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5564330FC514DB623BF9BC.taxon	diagnosis	Diagnosis. Shell small (to 26 mm), brown with one pale spiral band above periphery; animal blackish, yellow edge to foot, 2 yellow bands across snout, yellow tentacles; Malay Peninsula, southern South China Sea, Philippines; COI: HE 680619 – HE 680622, HE 680624, HE 680625.	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5564330FC514DB623BF9BC.taxon	materials_examined	Material examined. 18 lots. Shell (Fig. 2 F – H, N, O): H = 11.0 – 26 mm. Shape elongated conical (H / B = 2.40 – 2.63, SH = 3.00 – 3.40); not routinely decollate, 7 – 11 whorls remaining in well preserved shells, but apex and protoconch always eroded. Spire whorls moderately rounded, suture distinct; spire profile slightly convex, slightly concave towards apex; periphery rounded; relatively delicate. Adult lip only slightly thickened, not flared; sometimes 1 previous lip on final whorl; apertural margin sinuous in side view; anterior canal a weak notch. Sculpture on spire of straight axial ribs, usually becoming curved (opisthocyrt) on last 2 – 3 whorls, ribs rounded, ribs and interspaces of similar width, 20 – 27 (33) ribs on penultimate whorl, ribs becoming weaker and irregular on final whorl; smallest apical whorls with 3 spiral cords if well preserved, increasing to 6 by whorls 5 – 6, then becoming weak or disappearing, so that only a trace of 8 – 10 spiral elements is visible above periphery on penultimate whorl; base with 8 – 10 cords, of which 2 at periphery slightly enlarged, with marked groove between. No ventrolateral varix, but 0 – 3 indistinct or prominently raised and rounded varices may be present at any point on last whorl (Fig. 2 F). Surface with spiral microstriae on thick periostracum; short periostracal fringe or bristles remaining on larger striae (i. e. 8 – 10 striae macroscopically visible above periphery) if well preserved; surface sometimes covered by thick black concretion. Colour: brown, with broad cream band above periphery, often concealed by periostracum; band visible by transparency within aperture. Animal (Fig. 3 B): sides of foot dark grey, broad yellow margin; head black, snout black with 2 broad transverse yellow stripes (one at tip), tentacles and tentacle bases yellow (examined in two samples from Kedah and Surat Thani). Yellow coloration not preserved after storage in ethanol, but pattern visible as absence of black pigment. Range: Malay Peninsula, southern South China Sea, Philippines. Records: Burma: Kadan Kyun (King I.) (NHMUK 1887.3.10.189). Thailand: Ao Nam Bor, Phuket I. (NHMUK); Kradeh, Kanchanadit, 20 km NE Surat Thani (NHMUK 20100434). Malaysia: Bugang jetty, Merbok estuary, Kedah (NHMUK 20080700); Pulau Lumut, Selangor (USNM 661026). Indonesia: near Bengkalis, Sumatra (T. Goulding & B. Dayrat); Cirebon, Java (NNML); Mempawah, Borneo (MZB). Vietnam: Chilins, Vung Tau (ANSP 330740). Philippines: Abatan R., Bohol (MNHN); Ponson I., Camotes I. (USNM 287982). Habitat and ecology. In Malaysia and Thailand this species was found on firm, peaty mud and in shallow pools with leaf litter, in deep shade at the landward side of the Rhizophora belt. In the Abatan River mangal (Philippines) Lozouet & Plaziat (2008) recorded it on mud in puddles in the shaded inner reaches of the mangrove forest, where it was rare.	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5564330FC514DB623BF9BC.taxon	discussion	Remarks. This species is small, usually scarce and difficult to find in its shaded, muddy habitat among leaf litter. It appears to have been overlooked in previous studies of the mangrove-associated molluscs of Southeast Asia (e. g. it was not mentioned by von Martens 1897, Van Benthem Jutting 1956 or Brandt 1974). Molecular samples were available only from the Andaman Sea and Gulf of Thailand coasts of the Malay Peninsula. These showed no phylogeographic structure, in contrast to some other shallow-water marine gastropods in which a genetic break persists between the Indian and Pacific Oceans in this vicinity, consistent with repeated isolation of the two ocean basins during sea-level fluctuations associated with Plio-Pleistocene glaciations (Reid et al. 2006). This could suggest that expansion to the Andaman Sea from the western Pacific (where its sister species C. largillierti occurs) is relatively recent. No molecular samples from the Philippines were available, but this is an area of endemicity in the potamidid genus Cerithidea (Reid et al. 2013). Shells from the Philippines do not differ obviously from those from the rest of the range but, in view of the limited morphological distinction between the three species of the C. largillierti complex, the conspecificity of the population in the Philippines should be tested with molecular data. For comparison between the three species of Cerithideopsis in the Indo-West Pacific, see Remarks on C. australiensis below and Table 2.	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5264310FC51652654FFD5C.taxon	description	(Figures 2 I – M, P – T, 3 C, D, 4)	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5264310FC51652654FFD5C.taxon	etymology	Etymology. From its distribution, largely confined to Australia. Taxonomic history. Previously, this species has always been known under the specific name largillierti. Reid et al. (2008) first suggested that C. largillierti s. l. consisted of two species, from Japan and Australia respectively, with a relatively high genetic (K 2 P) distance for COI of 15 %.	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5264310FC51652654FFD5C.taxon	diagnosis	Diagnosis. Shell relatively large (to 48 mm), brown with 1 – 2 pale spiral bands, or white with 1 – 3 brown bands; animal black with dense yellow spots; tropical Australia and Gulf of Papua; COI: AM 932790, AM 932791, HE 680615 – HE 680617.	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5264310FC51652654FFD5C.taxon	materials_examined	Material examined. 42 lots. Shell (Fig. 2 I – M, P – T): H = 15.2 – 48.2 mm. Shape elongated conical (H / B = 2.30 – 2.64, SH = 3.13 – 3.48); not routinely decollate, 10 – 14 whorls remaining in well-preserved shells, but apex and protoconch always eroded. Spire whorls rounded, suture distinct; spire profile very slightly convex, slightly concave towards apex; periphery rounded; relatively solid. Adult lip only slightly thickened and flared; sometimes up to 3 previous lips and strong growth lines near end of final whorl; apertural margin sinuous in side view; anterior canal a weak notch. Sculpture on spire of straight axial ribs, becoming curved (opisthocyrt) on last 2 – 3 whorls, ribs rounded, ribs and interspaces of similar width, 15 – 24 (29) ribs on penultimate whorl, ribs becoming weaker and irregular on final whorl; smallest apical whorls with 2 – 3 spiral cords if well preserved, increasing to 5 by whorls 5 – 6, then disappearing, so that only a trace of 8 – 10 spiral elements is visible above periphery on penultimate whorl, stronger posteriorly; base with 8 – 10 cords, of which 2 at periphery slightly enlarged, with marked groove between. No ventrolateral varix, but 0 – 3 indistinct or prominently raised and rounded varices may be present at any point on last whorl, up to 7 in total on last 3 whorls (Fig. 2 J, M, Q, S). Surface with spiral microstriae on thick periostracum (Fig. 3 D); short periostracal fringe or bristles remain on larger striae (i. e. 8 – 10 striae macroscopically visible above periphery) if well preserved. Colour: brown, with broad cream band above periphery, sometimes additional pale band at suture; pattern often concealed by periostracum; in northwestern Australia shells are white with 1 – 2 brown bands above periphery and sometimes a brown line between 2 strong outermost basal grooves (Fig. 2 R – T); bands visible by transparency within aperture. Animal (Fig. 3 C): sides of foot and snout black with dense yellow spots, 2 larger yellow spots near tip of snout; tentacle bases yellow (Fig. 3 C from Northern Territory). Yellow coloration not preserved after storage in ethanol, but pattern visible as absence of black pigment (examined in two lots from Proserpine and Thirsty Sound, Queensland). Range: Tropical Australia and Gulf of Papua. Records: Western Australia: Cossack (AM C. 439257); Lookout Hill, Broome (NHMUK 20130437); Buccaneer Archipelago (AM C. 042509). Northern Territory: Ludmilla Creek, Darwin (NHMUK); Bing Bong station (AM C. 412930). Queensland: Forsyth I. (AM C. 108447); Mapoon (AM C. 014282); Missionary Bay, Hinchinbrook I. (NHMUK); Cockle Bay, Magnetic I. (NHMUK 20130435); Plum Tree, Thirsty Sound (AM C. 419622); Russell I., Moreton Bay (AM C. 410423); Lota Creek, Waterloo Bay, SW Moreton Bay (NTM P. 49902). Papua New Guinea: 30 miles E Port Moresby (AM C. 82943). Wells & Bryce (1986: 55) recorded this species from “ North West Cape, W. A. to Queensland ”. The southernmost records are from Moreton Bay, southern Queensland. Hinton (1979: caption of pl. 7) observed that this species was “ reasonably common in Gulf of Papua ”. Habitat and ecology. In northern Queensland it is found on mud and in shallow pools with leaf litter, in the shade of Ceriops trees on the edges of saltpans in mangrove areas. The snails bury themselves in the mud during neap tides. In Broome, Western Australia, it was found on soft mud beneath Avicennia trees in a wide belt of this tree fringing a coastal mudflat. Willan (2013) reported that it inhabits the middle and lower tidal zones of mangrove forests where the mud is soft, and remains in pools when the tide recedes.	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
03E987F40D5264310FC51652654FFD5C.taxon	discussion	Remarks. Shells from Western Australia are always pale in colour and of unusually thick texture (Fig. 2 R – T). This marine region is known for its high endemicity and the mangrove-associated gastropods include the endemic Cerithidea reidi Houbrick (Reid 2014), Littoraria cingulata (Philippi) and L. sulculosa (Philippi), besides several distinctive regional forms with low genetic divergence (Reid 1986; Reid, Dyal & Williams 2010). White shells with brown lines (2 above periphery and 2 below) are occasionally found as far east as Darwin (NTM P. 009694). Genetic study is required to test the status of the western form of C. australiensis. The three species of Cerithideopsis in the Indo-West Pacific are extremely similar in shell characters and there are no entirely diagnostic characters by which to separate them (Table 2). In overall size, C. malayensis is typically small (not exceeding 26.0 mm in shell length), while C. australiensis reaches largest size (up to 48.2 mm in shell length). Their shapes and rib counts show broad overlap. In shell colour, C. largillierti typically has two pale bands above the periphery, while C. malayensis has one and colour is more variable in C. australiensis, but this feature is not useful when the shell is encrusted with mud and algae, covered by a thick periostracum or when severely eroded. The headfoot of C. largillierti is black with yellow tentacle bases and tip of snout when living; that of C. malayensis is black with two yellow stripes across the snout and a yellow edge to the foot, while that of C. australiensis is black with yellow spots. In ethanol-preserved specimens the yellow coloration fades almost to white, but the black pigmentation remains. Available information indicates that these colour patterns are speciesspecific, but this requires confirmation. The distributions of the three species are entirely allopatric (Fig. 4) and this provides the simplest means of identification. Cerithideopsis australiensis is of small size relative to edible potamidids such as species of Terebralia, Telescopium and Cerithidea, and has not been found in densities that would appear sufficient to warrant collection for food. Willan (2013) noted that C. australiensis is never consumed by Aboriginal people in Australia. However, this has not always been the case; the species dominates many middens dated to around 2000 – 2500 BP on the coast of Papua New Guinea southeast of Port Moresby (Petchey et al 2012; specimens from Caution Bay examined).	en	Reid, David G., Claremont, Martine (2014): The genus Cerithideopsis Thiele, 1929 (Gastropoda: Potamididae) in the Indo-West Pacific region. Zootaxa 3779 (1): 61-80, DOI: http://dx.doi.org/10.11646/zootaxa.3779.1.8
