Paracentrotus lividus

Paracentrotus lividus (Lamarck, 1816)

(Fig. 25)

Echinus lividus Lamarck, 1816 — $ Drouët 1861: 210; Barrois 1888: 31;

Toxopneustes lividus (Lamarck, 1816) — $ Agassiz 1863: 23; $ Simroth 1888: 231;

Strongylocentrotus lividus (Lamarck, 1816) — $ Agassiz 1872: 446–447, pl. 5b, fig. 3, pl. 24, fig. 25; $ Barrois 1888: 75; John 1889: 285; $ Koehler 1895a: 225, 1898: 24; Jackson 1912: 162;

Paracentrotus lividus (Lamarck, 1816) — Koehler 1914b: 278; Mortensen 1927a: 306–309, figs. 175–177; $ Cadenat 1838: 367; Nobre 1938: 118–119, figs. 48–49, 66; $ Mortensen 1943a: 157–168, figs. 69–72, pl. 17, figs. 2–3, pl. 22, figs. 1–9, pl. 57, figs. 1–3, 11, 12, 20; $ Chapman 1955: 399; Harvey 1956: 51, 65; $ Tortonese 1965: 337–341, figs. 160–162; $ Marques 1983: 5–6, 1984: 105; Moyse & Tyler 1995: 678–680, fig. 12.8; Pereira 1997: 334; Pérez-Ruzafa et al. 1999: 52–53, 2002: 285–286; $ Cardigos et al. 2005: 165; García-Diez et al. 2005: 50; Schultz 2006: 194–195, figs. 361–363; Haddad & Barreiros 2008: 9, fig. 3a; Ávila et al. 2009: 27, 2010: 56; Micael & Costa 2010: 323; $ Micael et al. 2010: 329; $ Wisshak et al. 2010: 2382; Madeira et al. 2011: 249–250, figs. 5C, 6C, 7C; Micael et al. 2012: 3, 5.

non Psammechinus microtuberculatus (Blainville, 1825) — $ Marques 1983: 5 [misidentification].

See: Mortensen (1943a); Schultz (2006).

Occurrence: Mediterranean Sea and northeast Atlantic, from Ireland (Mortensen 1927a), along the coast of Europe (Nobre 1938) to Mauritania (Chapman 1955), including the archipelagos of the Azores (Marques 1989), Madeira (Alves et al. 2001), Selvagens (Pérez-Ruzafa et al. 2002), Canaries (Pérez-Ruzafa et al. 2003) and Cape Verde (Pérez-Ruzafa et al. 1999).

Depth: 0–80 m (Tortonese 1965), rarely below 30 m (Picton 1993); AZO: 0–40(?207) m (Koehler 1898, herein).

Habitat: preferentially rocky shores where it can bore holes in the rock (Schultz 2006); diet mainly of algae (Mortensen 1943a).

Larval stage: planktotrophic (Emlet 1995).

Fossil fauna: remains of this species, spines and test fragments were found in Pleistocene sediments of Santa Maria Island (Madeira et al. 2011). At the Pleistocene outcrop at Prainha, bore-holes were found on a basaltic rock about 5 m above present sea level, which were attributed to P. lividus boring activities (Ávila et al. 2009, 2010).

Commercial value: edible (Picton 1993).

Material examined: DBUA-ECH 123 (S„o Roque, SMG, AZO, c. 37°44’37”N, 25°38’19”W, 2012.11.16, intertidal; 1 spm, D = 5 mm); DBUA-ECH 138 (Poças de Santa Cruz, GRA, AZO, c. 39°05’16”N, 28°00’25”W, 2010.08.02, intertidal; 1 spm, D = 13 mm); DBUA-ECH 164 (Baia do Rosto do C„o, S„o Roque, SMG, AZO, c. 37°44’37”N, 25°38’19”W, 1990.07; 14 spms, D = 9–14 mm); DBUA-ECH 166 (off Vila Franca do Campo, SMG, AZO, 37°41’17”N, 25°25’06”W, 2006.07. 15, 129–207 m; 1 bt, D = 7 mm); DBUA-ECH 190 (Vila Franca do Campo, SMG, AZO, c. 37°41’39”N, 25°27’27”W, 2006.07. 21, 95–121 m; 1 bt, D = 3 mm); DBUA-ECH 280 (Ponta Delgada harbour, SMG, AZO, c. 37°44’12”N, 25°39’26”W, 1996.12.04; 1 spm, D = 34 mm); DBUA-ECH 287 (Rosto do C„o, S„o Roque, SMG, AZO, c. 37°44’37”N, 25°38’19”W, 1990.05. 14, 1 m; 1 spm, D = 45 mm); DBUA-ECH 323 (Islet of Mosteiros, SMG, AZO, c. 37°53’25”N, 25°50’06”W, 2011.07.07, 26 m; 2 spms, D = 8– 12 mm); DBUA-ECH 337 (Piscinas de Santa Cruz, FLS, AZO, c. 39°27’18”N, 31°07’30”W, 2007.07.22, intertidal; 7 spms, D = 15–49 mm); DBUA-ECH 338 (SMG, AZO, c. 37°50’06”N, 25°40’10”W, 1997.7, intertidal; 1 spm, D = 9 mm); DBUA-ECH 412 (Santa Cruz, GRA, AZO, c. 39°05’16.00”N, 28°00’25”W, 2010.08.06, intertidal; 2 spms, D = 51–58 mm); MB-NMHN 39–357 (Castelo Branco, FAY, AZO, c. 38°31’05”N, 28°43’23”W, 25 m, collected and identified by Vasco Marques as Paracentrotus cf. gaimardi; 1 bt, D = 9 mm); MB-NMHN 39–354 (Horta, FAY, AZO, c. 38°31’51”N, 28°37’23”W, 1979, collected and identified by Vasco Marques as Psammechinus microtuberculatus; 1 bt, D = 7 mm); MB-NMHN 39–355 (Castelo Branco, FAY, AZO, c. 38°31’05”N, 28°43’23”W, 1979, collected and identified by Vasco Marques as Psammechinus microtuberculatus; 1 bt and 1 dry spm, D = 6 mm).

Description: test circular, relatively low with a height of about 40%D in smaller specimens increasing to almost 60% in larger specimens. Apical disc dicyclic. Periproctal plates naked; Small individuals with three naked periproctal plates, one large and two other ones half the size of the large one. Genital pores closed in the smallest individual (D = 5 mm; DBUA-ECH 123). Ambulacral plates polygeminate, with four to five pore pares per plate at the ambitus in smaller specimens and five pore pairs throughout in larger specimens; one large primary tubercle per ambulacral plate, with secondary tubercles forming a zigzag series along the midline of the area; primary tubercles in the ambulacral plates of the same size as the ones in the interambulacra. Interambulacra with two regular series of primary tubercles flanked one or two sub-equal secondary tubercles. Peristome somewhat sunken, from 45– 60%D in smaller specimens (<9 mm D) to 34–36%D in larger specimens (> 33 mm D). Peristomal membrane with small-scattered plates. Primary spines long and robust, about 20–30%D in smaller specimens increasing to more 50–60%D in larger specimens. Globiferous pedicellaria with one large terminal tooth and one lateral tooth on each side. Colour variable, from dark green/purple to lighter green/purple or with primary spines dark coloured at the base and becoming lighter towards the tips.

Remarks: the genus Paracentrotus comprises just two extant shallow-water species, P. lividus (Europe and NW Africa waters) and P. gaimardi (South Atlantic tropical waters: Gulf of Guinea, Angola and Brazil) (Schultz 2006). Mortensen (1943a) compared and discussed several diagnostic characters considered in the previous literature and concluded that none could be considered as reliable due to the high morphological variation demonstrated by both species. Nevertheless, Mortensen considered that the best character was the ornamentation on the apical disc, although he commented that it was also subject to variation as animals from both species could present a rather weak striation. Another character discussed by Mortensen was the number of pore pairs being almost constantly five in P. lividus and usually four in P. gaimardi. Again, both species show a degree of overlapping variation with some specimens of P. gaimardi having plates bearing five pore pairs and specimens of P. lividus presenting four to six pore pairs. The collection of Museu Bocage houses an unreported specimen from the Azores, collected and identified by Marques Vieira as Paracentrotus cf. gaimardi. The specimen presents only four pore pairs at the ambitus, a character that Marques Vieira may have used to identify the Azorean animal as western P. cf. gaimardi. However, taking in to account the size of the Azorean specimen (= 9 mm), the lack of ornamentation of the apical disc, and the NE Atlantic origin, we strongly believe that the specimen represents a young P. lividus, a common inhabitant of the Azorean rocky shores.

Marques Vieira’s echinoderm collection at the Museu Bocage also houses three small animals (D = 6 mm, see Fig. 25 E–G) identified as Psammechinus microtuberculatus, a species believed to be endemic to the Mediterranean Sea (see below remarks under P. miliaris). Marques (1983) remarked that this species was the least frequent echinoid species in the Azores shallow waters. Thus, it is quite likely that the material housed at the Museum is the sole material used by Marques on which his report of P. microtuberculatus from the Azores was based. However, all three specimens possess ambulacral plates with four pore pairs per plate, a feature not found in Psammechinus. Furthermore, the valves of globiferous pedicellaria from the only complete specimen were typical of the genus Paracentrotus, presenting a single pair of lateral teeth beneath the terminal tooth, not several as would be expected in Psammechinus specimens. Apparently, Marques (1983) had misidentified juveniles of P. lividus as P. microtuberculatus.

Paracentrotus lividus is a typical inhabitant of the first few meters of the Azorean rocky shores, with a maximum reported depth in the Azores of c. 40 meters. Specimens dredged from 95–200 m all are slightly abraded naked tests possibly transported after the animals’ death to these depths. Additionally, Cardigos et al. (2005) recorded this species in the area of Don Jo„o de Castro Seamount (between Terceira and S„o Miguel islands), one of the rare examples in Azores of a shallow-water hydrothermal-active volcanic seamount (the top of the seamount lies 13 m deep). See also remarks under Arbacia lixula.