Echinolittorina punctata ( Gmelin, 1791 )

Reid, David G., 2011, 2974, Zootaxa 2974, pp. 1-65 : 16-24

Echinolittorina punctata ( Gmelin, 1791)

( Figures 4E–H, 6–8)

Turbo punctatus Gmelin, 1791: 3597 (refers to Adanson 1757: pl. 12, fig. 1; Senegalia [ Senegal]; lectotype ( Fischer-Piette 1942: 269, pl. 10, fig. 2a, b; Rosewater 1970: pl. 364, figs 9, 10; Rosewater 1981: pl. 2G) MNHN 5520, Île Gorée, Senegal, seen, Fig. 6N herein; of other 21 specimens (paralectotypes MNHN 22943, seen) mentioned by Fischer-Piette 1942, 3 are Melarhaphe neritoides ( Linnaeus, 1758) and 1 possibly Tectarius striatus ( King & Broderip, 1832)) . Dillwyn, 1817: 819–820.

Littorina punctata — Deshayes, 1843: 204. Reeve, 1857: Littorina sp. 66, pl. 13, fig. 66a, b. Hidalgo, 1867: 386–387 (in part, includes Afrolittorina africana (Krauss in Philippi, 1847)). Weinkauff, 1868: 274 (in part, includes E. pulchella ). Petit de la Saussaye, 1869: 122 (in part, includes Afrolittorina africana ). Monterosato, 1872: 33. Monterosato, 1875: 25. Monterosato, 1878: 83. Locard, 1886: 286. Kobelt, 1888: 169. Dautzenberg, 1891: 46. Locard, 1891: 190–191. Locard, 1897: 492– 493 (in part, includes E. caboverdensis ). Kobelt, 1907: 68–69, pl. 3, figs 10, 10a, pl. 112, figs 5, 6. Hidalgo, 1917: 394– 395. Tomlin, 1927: 296. Fischer-Piette, 1942: 268–269, pl. 10, fig. 2a, b. Nicklès, 1947: 4. Nicklès, 1950: 48–49 (in part, includes E. pulchella , E. caboverdensis ). Pasteur-Humbert, 1962: 36. Parenzan, 1970: 63, pl. 9, fig. 137. Bandel, 1974: 107, figs 18–22, 56, 57 (radula). Nicolay & Angioy, 1988: 29, figs. Poppe & Goto, 1991: 93, pl. 11, fig. 15. Barash & Danin, 1992: 42, fig. 44. Cachia, Mifsud & Sammut, 1996: 36–37, pl. 2, fig. 2. Macedo, Macedo & Borges, 1999: 120, fig. Ardovini & Cossignani, 2004: 21, 81, 3 figs.

Litorina punctata —Philippi, 1847: 198–199, Litorina pl. 4, fig. 11. Dunker, 1853: 11–12, pl. 2, figs 23–25. Weinkauff, 1878: 36, pl. 4, figs 1, 2 (in part, includes E. caboverdensis ). Weinkauff, 1883: 221 (in part, includes E. caboverdensis ). Carus, 1890: 351. Pallary, 1912a: 116–117.

Littorina (Melarhaphe) punctata —H. Adams & A. Adams, 1854: 314 (as Melaraphe ). Tryon, 1887: 248, pl. 44, fig. 60 (in part, includes E. pulchella , E. caboverdensis , Littoraria intermedia ( Philippi, 1846) , Littoraria cingulifera ( Dunker, 1845) ; as Melaraphe ). Nevill, 1885: 137 (as Melaraphe ). Dautzenberg, 1910: 125 (in part, includes E. caboverdensis ; as Melaraphe ). Dautzenberg, 1912: 46 (in part, includes E. pulchella ; as Melaraphe ). Pallary, 1920: 48 (as Melaraphe ). Priolo, 1953: 179 (as Melaraphe ). Nordsieck, 1968: 41, pl. 6, fig. 23.32 (as Melaraphe ). Sacchi & Rastelli, 1969: 2904–2906, fig. B (penis) (as Melaraphe ). Nordsieck, 1972: 229, fig. 7 (as Melaraphe ). Nordsieck, 1982: 62, pl. 26, fig. 23.32 (as Melaraphe ). Torelli, 1982: 71–72, fig. 40 (as Melaraphe ).

Littorina (Austrolittorina) punctata — Rosewater, 1970: 423, 474–476, pl. 364, figs 9, 10 (shell), pl. 365B (penis), pl. 367 (map) (in part, includes E. caboverdensis , E. pulchella , E. soroziczac , and probably L. saxatilis ( Olivi, 1792) and Afrolittorina knysnaensis (Krauss in Philippi, 1847)). Nordsieck & Garca-Talavera, 1979: 57, pl. 11, fig. 7. Rosewater, 1981: 24–26, pl. 2G (shell), 4B (radula) (in part, includes E. caboverdensis , E. pulchella , E. soroziczac ).

Nodilittorina (Echinolittorina) punctata — Reid, 1989: 99 (in part, includes E. caboverdensis , E. pulchella ). Kadolsky & Cataliotti-Valdina, 1999: 90–91. Öztürk, Buzzurro & Benli, 2004: 54, fig. 2.

Nodilittorina punctata —Gianuzzi-Savelli et al., 1997: 68, figs 170–173. D’Anna, 2001: figs 1–3 (as Nodlittorina). Reid, 2002a: 259–281.

Echinolittorina punctata — Williams et al., 2003: 83. Albano & Trono, 2008: figs 2, 3 (living animal). Antit et al., 2008: 2–3, fig. 3. Albano, 2010: 201-204, figs 1 (map), 2.

Echinolittorina punctata A— Williams & Reid, 2004: 2227–2251, fig. 6E (map). Williams & Duda, 2008: fig. 1 (phylogeny; as E. punctata B in error).

Echinolittorina (Amerolittorina) punctata A— Reid, 2009: figs 1, 37 (phylogeny; in fig. 1 as E. punctata B in error).

Tricolia rissoi Audouin, 1826: 41 , pl. 5, fig 18 ( Egypt; in part, includes Melarhaphe neritoides ; lectotype (here designated) MNHN 22968 is Melarhaphe neritoides (as noted by Pallary 1926: 79; specimen figured by Savigny 1817: pl. 5, fig. 18; reproduced by Audouin 1826; Bouchet & Danrigal 1982: fig. 47), seen; paralectotype MNHN 5786, seen, is E. punctata ).

Tricolia draparnaudii Audouin, 1826: 41 , pl. 5, fig. 19 ( Egypt; in part, includes Planaxis sulcatus ( Born, 1780) ; lectotype (here designated) MNHN 22967 (specimen figured by Savigny 1817: pl. 5, fig. 19; reproduced by Audouin 1826), seen; paralectotype MNHN 5728, seen, is P. sulcatus ( Bouchet & Danrigal 1982: fig. 46)).

Littorina draparnaudi — Pallary, 1926: 79, pl. 9, fig. 19.

Littorina marnat Potiez & Michaud, 1838: 279 , pl. 28, figs 9–10 ( St Thomas, Amérique septentrionale; lectotype ( Bandel & Kadolsky 1982: 23–24) MNHN 5520 from Île Gorée, Senegal, seen; in part, may include western Atlantic E. interrupta (C.B. Adams in Philippi, 1847) judging by locality ‘St Thomas’, fide Bandel & Kadolsky 1982: 23-24; figures indeterminate).

Phasianella tessellata Anton, 1838: 61 (Südamerika (in error); holotype MTD 1593, seen). Schniebs, 2000: 81, fig. 2a, b. Reid & Williams, 2004: 108.

Litorina syriaca Philippi, 1847: 165 , Litorina pl. 3, figs 21, 22 ( Syria; 6 syntypes SM ZI0050270 , seen).

Littorina (Melarhaphe) syriaca —H. Adams & A. Adams, 1854: 314 (as Melaraphe ).

Littorina syriaca — McAndrew, 1856: 123, 149. Petit de la Saussaye, 1869: 122. Monterosato, 1889: 32.

Littorina (Melarhaphe) punctata var. syriaca — Nevill, 1885: 137 (as Melaraphe ).

Turbo siculus Brugnone, 1850 : Giornale Armonia (not seen; synonymy fide Monterosato 1872; Puzzallo, Sicily, Italy; 2 syntypes HUJ 10.264 fide Mienis, 1975; not Nardo, 1847).

Littorina tigrina — McAndrew, 1854: 16, 21, 47 (not Litorina tigrina d’Orbigny, 1842 = Littoraria nebulosa ( Lamarck, 1822)) .

Littorina syriaca var. major Monterosato, 1889: 32 ( Tanger [Tangiers, Morocco]; nomen nudum).

Litorina punctata var. major — Pallary, 1912a: 117.

Littorina syriaca var. minor , carinata Monterosato, 1889: 32 (Casa Blanca [ Morocco]; non-binominal).

? Littorina perplexa Turton, 1932: 133 , pl. 28, fig. 960 (Port Alfred, South Africa; holotype OUM, seen; see also Reid & Williams 2004: 100–102).

Taxonomic history: Adanson (1757) used the vernacular name Le Marnat for this species, and his detailed description was based on his own observations and collections in Senegal. He also mentioned a variety said to come from China and Bengal; based on material in Adanson’s collection, Fischer-Piette (1942) identified this variety as the South American Echinolittorina peruviana ( Lamarck, 1822) . Gmelin (1791) based his Turbo punctatus on Adanson’s (1757) fig. 1, but this is a compound of two views of a living animal, shell and operculum, so there is not an unambiguous single figured specimen. Fischer-Piette (1942) explicitly selected as “le type” the shell that “nous parait-être le figuré”; since this was a matter of opinion it is regarded as a valid lectotype selection (ICZN, 1999: Art. 74.5) and not as an identification of the holotype. Potiez & Michaud (1838) validated Adanson’s vernacular, pre-Linnean name as Littorina marnat and used it for an indeterminate western Atlantic Echinolittorina species ; to minimize confusion Bandel & Kadolsky (1982) designated as lectotype the same specimen from the Adanson collection that is also the lectotype of Turbo punctatus .

Litorina syriaca was described by Philippi (1847) from material supplied by Krauss; syntypes have recently been discovered in SM (H. Niederhöfer, personal communication) and are accompanied by an original label in Philippi’s hand.

The holotype of Phasianella tessellata Anton, 1838 was identified as Littorina knysnaensis (= Afrolittorina knysnaensis ) by Schniebs (2000), but shown to be E. punctata by Reid & Williams (2004).

The original description of Turbo siculus Brugnone, 1850 in the Giornale Armonia has not been traced. Inclusion in the synonymy of E. punctata follows Monterosato (1872, 1875, 1878) and Priolo (1953). Syntypes have been located among material from Monterosato’s collection in HUJ ( Mienis 1975).

Turton (1932) described a juvenile, beachworn shell of 1.9 mm height from Port Alfred, South Africa, as L. perplexa . This was listed in the synonymy of E. punctata s. l. by Rosewater (1970), while Kilburn (1972) suggested that it was a patterned form of Afrolittorina africana . Certain identification is not possible, but Reid & Williams (2004) noted that the shell does resemble a juvenile of the E. punctata group, perhaps accidentally transported to South Africa.

Pallary (1920) listed L. tristis Mousson, 1873 as a synonym of E. punctata and this species was figured by Mousson (1874). The shell was described as elongate (SH = 2.27), dark brown and paler above, 8 mm long, neither colour pattern nor regular striation were mentioned, and the type locality was the river mouth at Rabat, Morocco. Form, colour and habitat are inconsistent with E. punctata . Rosewater (1981) listed the name in the synonymy of Melarhaphe neritoides , but the elongate form, large size and habitat argue against this. The evidence suggests that this is not a littorinid; assignment to another family, perhaps Assimineidae , should be considered.

There is a long history of confusion and misidentification among the three species of the E. punctata group and E. soroziczac (see Remarks on subgenus Amerolittorina , E. caboverdensis , E. pulchella and E. soroziczac ). Records of ‘ L. punctata ’ from Namibia ( Penrith & Kensley 1970a, b; Kensley & Penrith 1980) include misidentifications of both E. pulchella and Afrolittorina knysnaensis ( Kilburn 1972; Reid & Williams 2004; see Range of E. pulchella ). Misidentification of A. knysnaensis probably explains some of the South African records of ‘ L. punctata ’ listed by Barnard (1963) and Rosewater (1970), but those from the Langebaan ( Barnard 1963) and Knysna Lagoons ( Day 1969) apply to L. saxatilis , as noted by Kilburn (1972) and Reid (1996). The record of ‘ L. punctata ’ from Madeira by Nobre (1889, 1937) is believed to be based on a misidentification of L. saxatilis ( Segers et al. 2009; see Range below). Afrolittorina africana has occasionally been synonymized with E. punctata (Hidalgo 1868; Petit de la Saussaye 1869). Tryon (1887) included L. fraseri Reeve, 1857 in the synonymy of L. punctata , and reproduced Reeve’s figures, which represent Littoraria cingulifera and Littoraria intermedia . Risbec (1942) incorrectly applied the name ‘ L. punctata ’ to the Pacific species E. melanacme (E.A. Smith, 1876) .

Echinolittorina punctata itself has rarely been misidentified. Hidalgo (1867) pointed out the misidentification as L. tigrina (a synonym of Littoraria nebulosa ) by McAndrew (1854). Weinkauff (1868) noted his own earlier misidentification as L. caerulescens ( Lamarck, 1822) (a synonym of Melarhaphe neritoides ).

Diagnosis: Shell with 9–16 incised spiral lines or narrow grooves above periphery; grey to olive brown with aligned array of white spots. Penis bifurcate, with smooth tapering filament, mamilliform penial gland and glandular disc of similar size on side branch of base. Mediterranean to The Gambia. COI: GenBank AJ623031 , AJ623032 .

Material examined: 94 lots (including 14 penes, 5 pallial oviducts, 5 radulae).

Shell ( Fig. 6): Mature shell height 4.2–16.9 mm. Shape high turbinate (H/B = 1.27–1.61, SH = 1.40–1.83); spire whorls gently rounded; suture distinct; spire profile straight to slightly concave near apex; periphery of last whorl slightly angled. Columella hollowed and slightly pinched at base; eroded parietal area small or absent. Some Mediterranean specimens show 1–4 conspicuous growth interruptions on last whorl ( Fig. 6J). Sculpture of 9–12 primary spiral grooves above periphery (on spire whorls the 2–3 anteriormost are covered by suture); sometimes a few secondary grooves appear (by interpolation or division) near periphery and suture on last whorl, giving totals of 13–16 incised lines above and 6–9 below periphery; sculpture usually fine, sometimes faint or obsolete on shoulder of last whorl, rarely grooves become strong and up to one-third rib width at periphery; peripheral rib more prominent and 1.5–2 times width of adjacent ribs; spiral microstriae weak or absent, surface shiny. Protoconch 0.32 mm diameter, 2.4–2.5 whorls. Ground colour pale brown, olive brown or black brown, with regular opisthocline series of small grey to white spots; in darkest small shells white spots present at suture, periphery and base only; aperture dark brown with pale band at base; columella pale brown.

Animal ( Fig. 7): Head black, no unpigmented stripe across snout; tentacle pale around eye, with two longitudinal grey to black stripes (occasionally fused towards tip) and pale tip; sides of foot grey to black. Operculum: opercular ratio 0.36–0.42. Penis ( Fig. 7A–D, G–I): filament gradually tapering to pointed tip, 0.6–0.7 total length of penis, sperm groove ends terminally; mamilliform gland approximately same size as penial glandular disc, borne together on short projection of base, glandular disc projecting only slightly; penis unpigmented or slightly pigmented at base. Sperm not seen. Pallial oviduct ( Fig. 7E, F): first loop of albumen gland small; copulatory bursa separates at posterior end of straight section and extends back almost to albumen gland. Spawn: an asymmetrically biconvex pelagic capsule 0.3 mm diameter, with broad peripheral rim overhanging base, dome-shaped upper side sculptured by 2 concentric rings, containing single ovum (P.G. Albano, personal communication).

Radula ( Fig. 4E–H): Relative radula length 2.50–4.75. Rachidian: length/width 1.50–2.10; major cusp narrow, tip pointed or slightly rounded. Lateral and inner marginal: 4 cusps, tip of major cusp bluntly rounded or rounded; major cusps sometimes enlarged and outer cusps reduced to denticles (narrowed form; Fig. 4G, H). Outer marginal: 7–9 cusps; usually with 8–9 cusps and prominent flange on inside and outside of base; sometimes narrowed and with 7 cusps ( Fig. 4G, H).

Range ( Fig. 8): Eastern, southern and western Mediterranean Sea; Atlantic coast from southern Spain to The Gambia, Senegal and Canary Islands. Range limits based on verified material (with dates of collection for northern limits) and selected references (see below for discussion of literature records): Cadiz, Spain (1986; ZMA); Rabassa, Mallorca, Spain (2004; BMNH); Sitges, Spain (D. Kadolsky, personal communication); Nice, France (leg. Locard, late nineteenth century; MNHN); Santa Marinella, Lazio, Italy (2008; Albano 2010); Pozzuoli, Campania, Italy (2005; BMNH); Gallipoli, Puglia, Italy (2000; Albano & Trono 2008); Keratea, Greece ( Nicolay & Angioy 1988); Loutro, Sfakia, Crete, Greece ( BMNH); Izmir, Turkey ( IRSNB); Rodos, Greece ( Albano & Trono 2008); NE Cyprus ( Öztürk et al. 2004); 20 km N Tartous, Syria ( BMNH); Lake Timsah, Suez Canal, Egypt (1988; BMNH; Moazzo 1939); Alexandria, Egypt ( BMNH 1885.6.24.64); Les Aiguilles, Tabarka, Tunisia (1991; BMNH 20110105); Philippeville, Algiers, Algeria ( MNHN; ZMA); Tarhzoute, Agadir, Morocco ( BMNH 20110112); Playa des Ingles, Gran Canaria, Canary Is, Spain ( BMNH); Cap Blanc, Mauretania ( MNHN); Isle Gorée, Dakar, Senegal ( BMNH 20110108); Fajara, The Gambia ( BMNH 20110103); Casamance, Senegal ( Nicklès 1947).

This species has extended its range in the Mediterranean during historic time. It was not collected in Sicily by Philippi (1836, 1844), or by Aradas & Benoit (1874) and Monterosato (1872, 1875, 1878), although these latter authors mentioned a single finding by Brugnone in southeastern Sicily in 1850 (described as Turbo siculus ; see Taxonomic History above). Antit et al. (2008) have cited this as evidence for the virtual absence of E. punctata from Sicily in the nineteenth century, with only occasional settlement of temporary populations. They also suggested that it was absent on the Tunisian coast in the early twentieth century, because it was not recorded by Pallary (1904, 1906, 1914; or Dautzenberg 1883, or Seurat 1924). It was, however, present at this time to the west of Algiers ( Monterosato 1877; Pallary 1900), in southern and eastern Spain ( Hidalgo 1917), Egypt ( Savigny 1817; Weinkauff 1868; Pallary 1912a) and Syria (Philippi 1847; Pallary 1912b). Therefore, Antit et al. (2008) concluded that the range of the species was then disjunct, restricted to the warmer parts of the eastern Mediterranean while the main range lay in the western Mediterranean and Atlantic. However, in the second half of the twentieth century E. punctata has become common in the intervening region, for there are reports from Sicily ( Patanè 1946; Priolo 1953; Parenzan 1970; D’Anna 1986), Malta ( Cachia et al. 1996) and Tunisia ( Enzenross & Enzenross 2001; Antit et al. 2008; map in Williams & Reid 2004 refers to material collected in Tunisia in 1991, not 1971 as quoted by Antit et al. 2008; Cecalupo, Buzzurro & Mariani 2008). The northward expansion of E. punctata appears to be continuing, with new records reported from the southwestern coast (Tyrrhenian Sea) of Italy as far north as Lazio ( D’Anna 1997, 2001; Soppelsa et al. 2004; Albano 2010) and from the southeastern coast (Ionian Sea) in the region of Puglia ( Albano & Trono 2008). There is also a much earlier record from Capo Linaro, Lazio, by Brunelli (1928), but in the absence of illustrations or specimens this cannot be verified. According to Cossignani et al. (1992) it is not present in the Adriatic. There are few records from Greece and the Aegean Sea, as noted by Albano & Trono (2008). Öztürk et al. (2004) made the first records from Cyprus. Although it was not reported from the Suez Canal by an expedition in 1924 ( Tomlin, 1927), it later occurred in Lake Timsah within the Canal ( Moazzo 1939; BMNH).

In the northwestern Mediterranean McAndrew (1854) gave the range as Faro (southern Portugal) to Cartagena ( Spain). Hidalgo (1867) extended this range to Valencia and Barcelona, and subsequently recorded the distribution as the entire Mediterranean coast of Spain as far north as Mataro (just north of Barcelona) and Menorca. Bosch & Moreno (1983) recorded that the first collections from Mallorca were made in 1978 and 1981, and gave the northern limits as Valencia and the Bay of Palma. Giribet & Peñas (1997) confirmed its presence at Garraf (just south of Barcelona). On the French Mediterranean coast it was recorded from Roussillon, Cannes and Nice by Locard (1886; repeated by Carus 1890), but was said to be rare ( Locard 1891). Bucquoy, Dautzenberg & Dollfus (1898) listed the species from Roussillon on the authority of earlier authors, but it was not rediscovered. It was not reported from Corsica by Locard & Caziot (1900). The present distribution on the Mediterranean coast of France is unknown. These historical references suggest that occurrence north of Barcelona has been sporadic in the past.

On the Atlantic coast of Europe McAndrew (1854; as L. tigrina ) gave the localities Faro (southern Portugal), Asturias (also McAndrew 1856) and Galicia (northern Spain); these records were quoted by Hidalgo (1917), who also added his own from Cadiz ( Hidalgo 1911, 1917). The records from northern Spain have not been confirmed subsequently and are considered unreliable, but specimens are available from Cadiz (1986; ZMA), which appears to be the northernmost reliable record in the Atlantic at present. Nobre (1898, 1900, 1931, 1936) did not record this species in Portugal, but Macedo, Macedo & Borges (1999) gave the locality Ria de Faro, Algarve (as first mentioned by McAndrew 1854); the provenance and reliability of this record are unknown (see below). Although present on the Canary Islands (see list above) it is apparently absent from Madeira. In their detailed account of the molluscs of Madeira, Segers, Swinnen & De Prins (2009) did not record it, and suggested that the historical records of Nobre (1889, 1937) were probably based on misidentification of L. saxatilis . Nobre (1937) referred to his own record from Madeira (presumably Nobre 1889, a list of the collection of E. Schmitz) and to records by Watson and Johnson; however, Watson (1897) mentioned only specimens from himself and Johnson that were “young and in too bad condition for independent recognition”, and listed the species from Madeira only on the authority of Nobre. Specimens of L. saxatilis from the Atlantic islands are indeed often small and eroded, so the interpretation of Segers et al. (2009) is probably correct. Macedo et al. (1999) did list Madeira as a locality for E. punctata , but this was perhaps based on Nobre (1937); one of their figures (unlocalized) is of L. saxatilis , casting further doubt on the record. The report of ‘ L. punctata ’ from Casamance, Senegal, by Nicklès (1947) is assumed to refer to this species (rather than E. pulchella ), because it is close to other verified records from Senegal and The Gambia; if correct, this is the southernmost record.

Habitat: Recorded from sandstone, basalt, beachrock and concrete, from littoral fringe to upper eulittoral, in exposed and sheltered situations.

Zonation pattern and habitat have been recorded at a range of localities. In the Mediterranean, with a generally small tidal range, it occurs in the littoral fringe and down to the mid-eulittoral, overlapping with the sympatric Melarhaphe neritoides in the upper parts, but not extending to such high levels ( Palant & Fishelson 1968; Lipkin & Safriel 1971; D’Anna 1986; Barash & Danin 1992; Albano & Trono 2008). Both species can occur together in pools in the littoral fringe ( Bandel 1974; Albano & Trono 2008). Abundance is usually high, up to 630 per 400 cm 2 having been recorded in Sicily ( D’Anna 1986). Detailed accounts are available for shores in Israel ( Palant & Fishelson 1968; Lipkin & Safriel 1971). Here, E. punctata is found on bare rocks wetted by spray (tidal range only 30 cm), from the upper-eulittoral Chthamalus zone upwards; the smallest individuals occur at lower levels in the shelter of the barnacles, while larger snails are found higher up in crevices, but migrate down to breed (see also Sacchi & Rastelli 1969; D’Anna 1986). The animals are inactive when waves are too rough or rocks too dry, but move when wetted by tides during day or night, feeding on filamentous blue-green algae and diatoms ( Palant & Fishelson 1968; Lipkin & Safriel 1971; D’Anna 1986). In Senegal the species is also abundant and zonation is similar, from the littoral fringe to the mid-eulittoral, with maximum density in the middle of this zone, above the barnacle belt, and a monthly zonation pattern that follows the tidal cycle; it is indifferent to wave exposure and occurs on a range of substrates (laterite, dolerite, volcanic tuff) ( Sourie 1954). In Israel it is said to be absent from very calm and shallow coasts ( Lipkin & Safriel 1971), but it has been recorded in the sheltered conditions of Lake Timsah in the Suez Canal ( Moazzo 1939). Nuwayhid, Evans & Young (1985) reported weak evidence for an escape response to crushed conspecifics. The reproductive season in Israel lasts from June to September in males, but begins in March in females ( Palant & Fishelson 1968).

Remarks: This is a well-known intertidal species in the Mediterranean, where its distribution has been the subject of careful local recording and historical research, as reviewed above. During the twentieth century it has extended its central Mediterranean range to Tunisia, Sicily and northwards on the western coast of Italy as far as Lazio, but it is unclear if there has been any similar extension on the Mediterranean coasts of Spain and France. Whether this is connected with anthropogenic climate change is unknown, but a number of thermotolerant species are also extending their range in the northwestern Mediterranean ( Lejeusne et al. 2009). Albano (2010) suggested that the predominantly southern distribution of E. punctata in the Mediterranean was a consequence of high temperatures being required for spawning, which is known to occur during summer months in Israel ( Palant & Fishelson 1968). Its distribution is most well documented in the cooler western Mediterranean basin. Here, the confirmed northern records of Sitges, Mallorca, Lazio and Puglia (excluding Sardinia, Corsica and the Adriatic) correspond closely with the isothermal contour for an average sea-surface temperature of 21°C for April–September (Physical Sciences Division, Earth System Research Laboratory, NOAA). However, the common occurrences in the Alboran Sea and nearby Atlantic (Cadiz and Morocco), and the historical records from southern France, are from areas where temperatures are 1–1.5°C cooler. A straightforward correlation with sea-surface temperature is likely to be too simplistic to explain fully the distribution of a planktotrophic species, and other variables such as current flows and settlement conditions may be significant.

Antit et al. (2008) discussed historical evidence for a disjunct distribution in the warmer parts of the eastern and western Mediterranean, although they suggested that gene flow between the two was probably maintained by larval dispersal. Recent range expansion appears to have produced a continuous distribution across the southern Mediterranean. Lipkin & Safriel (1971) noted a difference in colour between eastern and western Mediterranean specimens, but gave no details; this has not been confirmed.

Noy, Lavie & Nevo (1987) measured allozyme variation in populations from Israel, and found it less variable than in sympatric Melarhaphe neritoides . Correspondingly, it was less resistant to organic and inorganic pollutants ( Nevo et al. 1986). Exposure to heavy metal pollution was found to produce differential survival of allozyme genotypes, both in the laboratory ( Lavie & Nevo 1987) and in the field ( Nevo, Lavie and Noy 1987). Allozyme frequencies were also sensitive to crude oil and detergent in laboratory tests ( Nevo & Lavie 1989).

Sacchi & Rastelli (1969) reported sexual dimorphism in shell height, females being about 1 mm larger. The larger size of females has been reported in many littorinids (e.g. Reid 1986, 1996, 2009).

The variation in radular dentition described here is a further example of a common phenomenon in Echinolittorina , seen at its most extreme in some western Atlantic species ( Reid 2009) and also recorded in some Indo-Pacific species ( Reid 2007). In the ‘narrowed’ radula type ( Fig. 4G, H) there is a correlated reduction in width of the rachidian tooth, enlargement of the major cusp on both lateral and inner marginal tooth, and narrowing of the outer marginal tooth together with reduction in the number of its cusps. The explanation and functional significance remain unknown, but there is a possibility of ecophenotypic control according to the substrate for grazing, as is known in other littorinid genera (see discussion by Reid 2009: 83–85).

As observed by Landau, Marquet & Grigis (2004), E. ariesensis (Fontannes, 1880) from the early and middle Pliocene of the western Mediterranean is probably conspecific. Kadolsky & Cataliotti-Valdina (1999) suggested that the absence of Pleistocene fossils of E. punctata from the Mediterranean and Morocco implies a recent (Holocene) immigration to the Mediterranean from the Atlantic.

The shells of the three species of the E. punctata group are closely similar. There are minor differences in the range of shape and sculpture of each ( Figs 6, 9, 12, Table 1) and in particular E. caboverdensis is the narrowest and tends to have weak sculpture. There are no anatomical differences. Identification rests on genetic information and geographical distribution, since the three are allopatric ( Fig. 8). Echinolittorina punctata is often sympatric with Melarhaphe neritoides , with which it has occasionally been confused (e.g. Weinkauff 1868); the latter is smaller (to 9 mm), smooth, with broader columella, and the shell is grey to brown, with no distinct pattern of pale spots.