Cerithidea reidi Houbrick, 1986

Reid, David G., 2014, The genus Cerithidea Swainson, 1840 (Gastropoda: Potamididae) in the Indo-West Pacific region, Zootaxa 3775 (1), pp. 1-65 : 36-37

Cerithidea reidi Houbrick, 1986

( Figures 2 G, 10Q–V, 11)

Cerithidea obtusa — Allan, 1950: 87, pl. 17, fig. 19. Hinton, 1978: 7, fig. Wells, 1981: 254. Wells & Bryce, 1986: 54, pl. 11, fig. 128. (All not Lamarck, 1822.)

Cerithidea reidi Houbrick, 1986: 280 –286, figs 1–4, 9 and 11–13 (radula), 16 (map)

(Willies Creek, N of Broome, Western Australia; holotype WAM 3380-84; 1 paratype AM C.144144; 10 paratypes USNM 828823 seen) .

Wells & Bryce, 1988: 54, pl. 11, fig. 128. Cecalupo, 2006: 135, 233–234, pl. 57, fig. 14 (in part, includes C. anticipata , C. dohrni ). Willan, 2013: 75 –77, fig. 7. Reid et al., 2013: figs 1 (phylogeny), 2 (map).

Cerithidea (Cerithidea) reidi — Wilson, 1993: 133, pl. 15, fig. 17a, b.

Taxonomic history. Until clarified by Houbrick (1986), there was confusion about the identity of the two Australian Cerithidea species. Until then, this endemic Western Australian species had been figured several times under the name ‘ C. obtusa ’.

This species was named for the author by Richard Houbrick; he inscribed a reprint with the epigram “to David – immortalized until synonymized”!

Diagnosis. Shell: periphery rounded or weakly angled; aperture flared, anterior canal and apertural projection well developed; 19–22 axial ribs on penultimate whorl; ventrolateral varix a slightly enlarged rib at 190–250°; 5 broad spiral cords on spire, 5–10 above periphery on last whorl; whitish fawn with orange brown spiral grooves and lilac aperture. Northern Western Australia. COI GenBank HE680236 –680238.

Material examined. 15 lots.

Shell ( Fig. 10 Q–V): H = 46.0–60.0 mm (to 61 mm, Houbrick 1986). Shape elongated conical (H/B = 1.95– 2.38, SH = 2.36–2.80); decollate, 6–8 whorls remaining; spire whorls rounded, suture distinct; spire profile straight to slightly convex; periphery rounded or weakly angled; moderately solid. Adult lip flared, moderately thickened; apertural margin planar in side view; strong anterior projection adjacent to deep notch of anterior canal. Sculpture on spire of straight to slightly curved (opisthocyrt) axial ribs, often bifurcating or trifurcating posteriorly (adapically) to give a row of granules or short axial wrinkles at suture; ribs prominent, rounded, ribs and interspaces of equal width, 19–22 ribs on penultimate whorl; becoming weak on last whorl (especially before ventrolateral varix); continuing as closely spaced, sometimes rugose, axial wrinkles after ventolateral varix, fine on base; spire whorls with 5 strap-like spiral cords, often forming weak nodules where they cross axial ribs, usually increasing by interpolation of narrower threads to give 5–10 spiral cords and threads above periphery on final whorl; base with 9–14 narrow ridges, peripheral ridge narrower than primary cords above, but is larger than other basal ridges. Ventrolateral varix a slightly enlarged rib at 190–250°. Surface with faint spiral microstriae on periostracum. Colour: whitish fawn, palest at suture, spiral grooves orange brown to lilac grey; aperture mauve, lilac or pale pinkish brown, spiral lines showing through faintly, lip white to cream.

Animal ( Fig. 2 G): Head and base of tentacles pinkish fawn with cream spots; anterior half of snout blackish grey with scattered yellow spots; tentacles cream, black annular rings; sides of foot fawn with darker specking and paler patches, small yellow spots at margin; sole of foot pale grey; mantle pinkish grey.

Range ( Fig. 11 ): N Western Australia (WA). Records: Australia: Gales Bay, Exmouth Gulf, WA ( Houbrick 1986: WAM 2434-84) ; Barrow I., WA ( USNM 694228); Willies Creek, N of Broome, WA ( NHMUK 20130246; USNM 828823); Buccaneer Arch., WA (AM C. 042225); Port Warrender, Admiralty Gulf, WA ( WAM S46091 ; Houbrick 1986).

Habitat and ecology. Near Broome the species is found on trunks of Ceriops bushes and trees, close to deep tidal creeks crossing bare salt pans. Wells & Slack-Smith (1981) reported it in the higher tidal levels of the mangrove forest, including Ceriops and Aegialitis zones, on trunks up to 2 m above ground level, at densities of up to 1.65 /m2.

Remarks. As observed by Houbrick (1986), this species is closely related to C. anticipata (see Remarks on the latter). Houbrick (1986) reported that the distributions of the two just overlap in the Admiralty Gulf of northern Western Australia, where C. anticipata was said to be larger and more like C. reidi in sculpture (see Remarks on C. anticipata ). However, photographs seen of twelve specimens from Port Warrender in the Admiralty Gulf (WAM S46332 , S46081 , S46091 ; specimens from study of Wells 1981) all appeared to be small C. reidi . Sympatric occurrence of the two species remains to be confirmed. It is possible that closer study may reveal hybridization and intergradation in the narrow region of potential overlap. The principal differences between typical examples of the two are the larger size of C. reidi (46–61 mm, cf. 24–48 mm in C. anticipata ) and its whitish shell colour with brown spiral grooves and mauve to lilac aperture (cf. brown shell with darker ridges and no mauve coloration within aperture in C. anticipata ; Fig. 10A–O ). There are also subtle differences in shell sculpture; in C. anticipata the axial ribs are narrower and more prominent, stronger and more distant on the final whorl after the ventrolateral varix, and the spiral cords are usually narrower (broad and strap-like in C. reidi ). The animal of C. reidi is paler in colour, but it is not known if this difference is consistent across the range of both species.

Cerithidea reidi is the largest member of the genus. Its size is rivalled only by C. obtusa from Southeast Asia, but that species has a broader shell with more swollen whorls, a more heavily thickened aperture and brown cords ( Fig. 8 ).

Figures

FIGURE 2. Living animals of Cerithidea species (not to scale). A. C. charbonnieri, Tapi R. estuary, Surat Thani, Thailand. B. C. obtusa, W Johore, Malaysia. C. C. anticipata, Brunswick R., NSW, Australia. D. C. quoyii, Singapore. E. C. moerchii, Kumamoto City, Kumamoto Pref., Kyushu, Japan. F. C. tonkiniana, Kumamoto City, Kumamoto Pref., Kyushu, Japan. G. C. reidi, Port Smith, Western Australia. H. C. weyersi, Tha Pom, Krabi, Thailand. Photography credits: C, D. Riek; D, S. K. Tan; E, F, H. Fukuda (from Fukuda, 2000). H, B. Craig.

FIGURE 8. Cerithidea obtusa. A, Cerithium obtusum Lamarck, 1822, lectotype, Timor (probably in error) (MHNG INVE 51623). B – E, Melaka, Malaysia (NHMUK 20130237; views of same specimen). F, Phuket I., Thailand (NHMUK 20100441). G, H, Port Canning, West Bengal, India (NHMUK 20130240). I, Jelutong, Pulau Ubin, Singapore (NHMUK 20130239). J – M, Melaka, Malaysia (NHMUK 20130238; views of same specimen). Photography credit: A, MHNG.

FIGURE 11. Distribution of Cerithidea anticipata (squares), C. reidi (stars), C. quoyii (circles), C. andamanensis n. sp. (crosses) and C. dohrni (triangles). Solid symbols, specimens examined; open symbols, literature records: A, Houbrick (1986); B, Quoy & Gaimard (1834); C, Morlet (1889).

FIGURE 10. A – P, Cerithidea anticipata. Q – V, C. reidi. A, Cerithium kieneri Hombron & Jacquinot, 1848, holotype, Raffles Bay, Coburg Peninsula, Northern Territory, Australia (MNHN 25692). B, C, Buffalo Creek, Northern Territory, Australia (NHMUK 20130241). D, Casuarina Beach, Northern Territory, Australia (NHMUK 20130242). E – G, Kokenau, Mimika R., East Papua, Indonesia (AM C. 458258). H, I, Rowes Bay, Townsville, Queensland, Australia (NHMUK 20130243). J, Moa I., Torres Strait, Queensland, Australia (NHMUK 20130244). K – M, Moreton Bay, Queensland, Australia (NHMUK 20130245; views of same specimen). N – P, Merauke, East Papua, Indonesia (AM C. 121289; N, O views of same specimen). Q – V, Willies Creek, N of Broome, Western Australia (NHMUK 20130246; same lot as type series; T – V views of same specimen). Photography credit: A, MNHN.