Ophidiaster ophidianus ( Lamarck, 1816 )

Madeira, Patrícia, Kroh, Andreas, Cordeiro, Ricardo, De, António M., Martins, Frias & Ávila, Sérgio P., 2019, The Echinoderm Fauna of the Azores (NE Atlantic Ocean), Zootaxa 4639 (1), pp. 1-231 : 93-94

Ophidiaster ophidianus ( Lamarck, 1816)

( Fig. 19 )

Reports for the Azores:

Asterias loevigata Lamarck—? $ Drouët 1861: 93, 211;

Ophidiaster ophidianus Agassiz, 1836 — $ Barrois 1888: 71;

Ophidiaster sp.—? $ Simroth 1888: 231;

Ophidiaster ophidianus ( Lamarck, 1816) — $ Sladen 1889: 403; $ Perrier 1894: 330, 1896a: 44; $ Koehler 1909: 92; Koehler 1914b: 274, 1924: 163–164; H.L. Clark 1921a: 79; Nobre 1924: 89; $ Nobre 1930: 68–69, 1938: 46, fig. 20; $ Cadenat 1938: 351, 373; Madsen 1950: 219; $ Tortonese 1965: 160–164, figs. 75–77; $ Pawson 1978: 10, fig. 3; $ Marques 1983: 2; A.M. Clark & Downey 1992: 281–282, figs. 44e, f, pl. 69, fig. F; $ Wirtz & Vader 1996: 17–22; Pereira 1997: 335; $ Morton et al. 1998: 63, figs. 2.5Y, 3.4Z, 3.5T, 5.2L, 8.1N; Pérez-Ruzafa et al. 1999: 47–48, 2002:280; $ Cardigos et al. 2005: 165; García-Diez et al. 2005: 47; $ Micael et al. 2006: 5, 2011: 205–216, figs. 2–7, 2013: 1087–1095, 2014: 1–10, figs. 2–3; Micael & Costa 2010: 322; Micael et al. 2012: 6.

Type locality: Western Mediterranean Sea.

See: Tortonese (1965); A.M. Clark & Downey (1992).

Occurrence: Mediterranean Sea and Northeast Atlantic; from the North African coasts ( Madsen 1950) south to Rolas islet in S„o Tomé ( Koehler 1914b), including the archipelagos of the Azores ( Marques 1983), Madeira ( Augier 1985), Selvagens ( Pérez-Ruzafa et al. 2002), Canaries ( Pérez-Ruzafa et al. 2003), Cape Verde (Pérez- Ruzafa et al. 1999) and Saint Helena ( Mortensen 1933c).

Depth: 0–105 m (A.M. Clark & Downey 1992); AZO: 0–165(?823) m ( Sladen 1889, Morton et al. 1998).

Habitat: rocky and coralligenous habitats ( Tortonese 1965), occasionally found on soft sediments ( Koukouras et al. 2007); in Azores common among rocks at low-tide and also in rock pools ( Morton et al. 1998).

Larval stage: lecithotrophic ( Micael et al. 2014).

Material: DBUA-ECH 075 (Baixa do Cerco, Caloura, SMG, AZO, c. 37°42’20”N, 25°30’30”W, 2010.08. 13, 20 m; 1 spm, R = 67 mm, r = 7 mm); DBUA-ECH 076 (FRM, AZO, c. 37°16’14”N, 24°46’52”W, 1990.06; 1 spm, r = 10 mm); DBUA-ECH 080 (Poços, S„o Vicente, SMG, AZO, c. 37°50’06”N, 25°40’10”W, 1996.07. 20, 30 m; 2 spms, R = 79–93 mm, r = 10–12 mm); DBUA-ECH 081 (Poços, S„o Vicente, SMG, AZO, c. 37°50’06”N, 25°40’10”W, 1996.07. 17, 12 m; 3 spms, R = 110–122 mm, r = 10–13 mm); DBUA-ECH 082 (Banco Jo„o de Castro, AZO, c. 38°13’18”N, 26°36’12”W, 1996.07. 27, 30 m; 1 spms, R = 120 m, r = 15 mm); DBUA-ECH 112 (Vila do Porto, SMA, AZO, c. 36°56’42”N, 25°08’50”W, 1990.06; 1 spm, R = 122 mm, r = 13 mm); DBUA-ECH 409 (Poças de Santa Cruz, GRA, AZO, c. 39°05’16”N, 28°00’25”W, 2010.08.5, 1– 2 m; 2 spm, R = 126–138 mm, r = 10–15 mm); DBUA-ECH 410 (Santa Cruz, GRA, AZO, c. 39°05’16”N, 28°00’25”W, 2010.08.6, intertidal; 1 spm, R = 130 mm, r = 20 mm).

Description: disc small with five relatively long, cylindrical arms slightly constricted at the insertion with the disc and a blunt distal extremity; many specimens with missing distal part of the arms or arms with different degrees of regrowth. Body densely covered by granulation, with larger flattened granules intermingled by finer granules. Papular areas in eight regular longitudinal rows. Maximum number of papular pores per area from 8–10 in the smallest specimen (DBUA-ECH 075, R = 67 mm) increasing progressively with the size of the animals to more than 20. Abactinal plates cruciform. Adambulacral plates bearing two blunt, rounded furrow spines, distal one smaller than proximal one. One large, thick, blunt subambulacral spine; no pedicellaria. Colour (in vivo) orange to bright red with or without darker blotches. Colour (in ethanol): whitish with some traces of the original orange colouration.

Remarks: On redescribing Ophidiaster guildingii Gray, 1840 , H.L. Clark (1921a) concluded that this Western Atlantic species can be distinguished from the Eastern Atlantic O. ophidianus primarily by the relative shape of the spines in the adambulacral armature, but also by its colour pattern, slender rays, coarser granulation and larger and fewer papulae. Mortensen (1933c) commented that the colour pattern could not be used as a diagnostic character, since animals of O. ophidianus from Santa Helena and the Canaries can also present a molted pattern, a character considered to be characteristic of O. guildingii . Madsen (1950) believed that both forms were the same species, and suggested to demote O. guildingii to a subspecies of O. ophidianus . Tortonese (1965) commented on the high variability in colour patterns presented by Mediterranean specimens, from bright orange, red, pink to violet, with or without spots of variable number and size. Nataf & Cherbonnier (1975) noted that the number of papillae is highly variable too, depending on the size of the animals. Our own observations on Azorean specimens are in accordance with the data presented by these authors. Nataf & Cherbonnier (1975) also observed that the granulation is also variable, a trait as well observed by us. Pawson (1978) recommended that the limits of variation, particularly of the colour patterns should be further studied. Most of the individuals housed in the DBUA-ECH collection showed no presence of conspicuous blotches, however little or nothing of the original colour survived in the preservation medium. In Wirtz & Debellius (2006: 276) a photograph taken in Faial Island (Azores) of two specimens side by side can be found: one uniform bright red and the other bright red with small dark blotches. Sympatric occurrence of these two-colour morphs was observed in the field by us ( Figs. 19E, F ). In a phylogeographic study by Micael et al. (2014) on O. ophidianus populations from the Azores, Madeira and Mediterranean, no evidence of significant differences were found, suggesting a recent range expansion.

The deep-water O. reyssi (see below) the only other known Ophidiaster species in the Azores can be easily distinguished from O. ophidianus by the presence of pedicellaria and by the overall shape of the body with arms tapering from a broad base. Additionally, O. reyssi can also be distinguished from all other Ophidiaster species by the isolated small bead-like subambulacral spines and a very fine body granulation (A.M. Clark & Downey 1992).

Drouët (1861) published the first possible report of this species in the archipelago under the name Asterias loevigata . Simroth (1888) found a specimen identified as Ophidiaster ophidianus at Ponta Delgada Museum, which he believed to be equivalent to Drouët’s Asterias loevigata . Barrois (1888) contested Drouët identification and place it under the name O. ophidianus , one of the most common sea stars of the present-day Azorean shallow water ( Morton et al. 1998; Micael et al. 2010). The closest name to the original identification is A. laevigata ( Linnaeus, 1758) , now accepted as Linckia laevigata ( Linnaeus, 1758) , a sea star of similar shape but restricted to the Indo- Pacific, which makes it an unlikely candidate. However, the subspecies Asterias laevigata varietas Lamarck, 1816 is considered a synonym of Hacelia attenuata a species present in the Azores (A.M. Clark & Downey 1992; see above). The only description provided by Drouët (1861) and by Simroth (1888) is the bright red and orange red colour of the specimens, respectively. Unfortunately, in the Azores both species O. ophidianus and H. attenuata can have bright red and orange colours. In the historical collection of the Museum Carlos Machado (Ponta Delgada, S„o Miguel Island) we have found some animals belonging to O. ophidianus . However, we could not ascertain if those specimens were the same as the ones referred by Simroth. Thus, without the original material it is impossible to further discuss the original identification, and considering the conspicuous presence of O. ophidianus in the Azorean shallow waters, we are inclined to accept Barrois (1888) rectification, a view also accepted by Pereira (1997). In any case, Nobre (1924, 1930) place Simroth’s record under O. ophidianus , but we could not ascertain if Nobre saw Simroth’s original material. Sladen (1883, 1889) reported this strictly shallow-water species to the Azores from a depth of 823 m (H.M.S. Challenger, sta 75: 38°38’00”N, 28°28’30”W), though showing some concerns due to the size of the specimen since in his opinion it was almost too small for an accurate determination, an opinion later joined by H.L. Clark (1921a). Nevertheless, the station depth was in all probability much shallower than the one reported (see remarks under Astropecten hermatophilus ), about 91–165 m, which falls in the maximum depth limit for O. ophidianus . Additionally, among the material housed at DBUA-ECH we have found a specimen collected 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. This species was also recorded by Cardigos et al. (2005) in the same area.

Figures

FIGURE 19. Ophidiaster ophidianus (Lamarck, 1816) (DBUA-ECH 081: A–D; DBUA-ECH 409: E). Dorsal view (A); ventral view (B); detail of the arm and disc, dorsal view (C), ventral view (D); molted colour pattern (E); animal in situ (Pico Island, Azores, ca. 38°23'22"N, 28°15'04"W, 2010.08.20, 1 m: F).