Genocidaris maculata Agassiz, 1869

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 : 116-118

Genocidaris maculata Agassiz, 1869

( Fig. 27 )

Reports for the Azores:

Temnechinus maculatus Agassiz, 1869 .— Agassiz 1872: 165, 215, 286–289, pl. 8, fig. 1–18; $ Koehler 1898: 21–22, pl. 8, figs. 3, 9;

p.p. Sphaerechinus granularis — $ Agassiz 1881: 106–107;

Genocidaris maculata Agassiz, 1869 — Mortensen 1903: 85, 1927a: 292, 1943b: 358–362, figs. 219, 220, pl. 18, figs. 37– 47; $ Koehler 1909: 226–227, pl. 31, fig. 3; Koehler 1921b: 115–116, fig. 76; $ H.L. Clark 1925: 76–77; Tortonese 1965: 321– 322, fig. 150; Serafy & Fell 1985: 21; Pereira 1997: 334; García-Diez et al. 2005: 50; Mironov 2006: 211–212; Micael & Costa 2010: 323; Micael et al. 2012: 4;

Gonocidaris maculata Agassiz, 1869 — Koehler 1914b: 278, 283;

Genocidaris maculata splendes Mortenten (1927b) — Mortensen 1943b: 362–363, fig. 221a.

Type locality: Caribbean waters.

See: Agassiz (1869: 262–263); Mortensen (1943b); Mironov (2006); Benavides-Serrato et al. (2012: 70).

Occurrence: Mediterranean Sea and Atlantic (Tortonesen 1965); in the West from Cape Cod, through the Caribbean to North Brazil waters ( Serafy & Fell 1985); in the East from the North African coasts to the Gulf of Guinea ( Cadenat 1938), including the Azores (Koehler 1990), Madeira ( Jesus & Abreu 1998), Canary archipelagos ( Mortensen 1943b), and Gorringe, Josephine and Seine seamounts ( Mironov 2006).

Depth: 12–500 m ( Tortonese 1965); AZO: (?0)20–200(?823) m ( Agassiz 1881, herein).

Habitat: sandy to coralligenous substrates ( Koehler 1909, 1921b); feeds on bottom material, ingesting small benthic animals (e.g., foraminiferans, molluscs and bryozoans; Serafy & Fell 1985).

Larval stage: planktotrophic ( Emlet 1995).

Material examined: DBUA-ECH 144 (off Vinha da Areia, Vila Franca do Campo, SMG, AZO, 37°42’11”N, 25°25’04”W, 2006.09.05, 66 m; 2 bts, D = 4–7 mm); DBUA-ECH 146 (off Ribeira das Tainhas, SMG, AZO, 37°41’57”N, 25°25’08”W, 2006.07. 24, 144–198 m; 2 bt, D = 4–5 mm); DBUA-ECH 147 (off Vinha da Areia, Vila Franca do Campo, SMG, AZO, 37°42’09”N, 25°25’04”W, 2006.09.05, 81 m; 1 bt, D = 4 mm); DBUA-ECH 149 (off Ribeira das Tainhas, SMG, Azores, 37°42’01”N, 25°25’01”W, 2006.07. 24, 117–145 m; 1 bt, D = 6 mm); DBUA- ECH 151 (S„o Vicente, SMG, AZO, c. 37°50’06”N, 25°40’10”W, 1997.07. 14, 30 m; 1 spm, D = 7 mm); DBUA- ECH 153 (S„o Vicente, SMG, AZO, c. 37°50’06”N, 25°40’10”W, 1997.07. 14, 30 m; 1 spm, D = 7 mm); DBUA- ECH 154 (Água d’Alto, SMG, AZO, c. 37°42’55”N, 25°28’27”W, 1991.07.30; 1 spm, D = 7 mm); DBUA-ECH 155 (Poços de S„o Vicente, SMG, AZO, c. 37°50’06”N, 25°40’10”W, 1996.07.08, intertidal; 1 spm, D = 7 mm); DBUA-ECH 159 (Vila Franca do Campo, SMG, AZO, 37°41’39”N, 25°27’11”W, 2006.07. 21, 95–121 m; 3 bts, D = 5–6 mm); DBUA-ECH 160 (S„o Vicente, SMG, AZO, c. 37°50’06”N, 25°40’10”W, 1997.07.14, 1991.07.11; 1 specimen, D = 7 mm); DBUA-ECH 186 (Vila Franca do Campo, SMG, AZO, 37°41’34”N, 25°27’15”W, 2006.07. 19, 126–171 m; 1 bts, D = 5 mm); DBUA-ECH 204 (Baixa do Jo„o Lopes, SMA, AZO, c. 37°01’13”N, 25°10’05”W, 2014.06. 26, 30–35 m; 1 spm, D = 6 mm); DBUA-ECH 221 (S„o Vicente, SMG, AZO, c. 37°50’06”N, 25°40’10W ”, 1997.07.14, 1997.07. 11, 20 m; 1 spm, D = 5 mm); DBUA-ECH 327 (Sabrina Bank, SMG, 37°52’55”N, 25°54’25”W, 2011.07.08, 200 m; 1 spm, D = 8 mm); L09D9B20S01 (Gorringe Bank, 36°42’49”N, 11°09’54”W, 2009.09. 13, 130 m; 2 bt, D = 6 mm); DOP 3015 (Channel PIX–FAY, AZO, 38°34’15.60”N, 28°32’31.20”W, 2008–06– 16, 50 m; 1 spm, D = 8 mm).

Description: test hemispherical, relatively high, height varying from about 48–50%D in smaller specimens (D <4 mm) to 65–70%D in larger specimens (D> 6 mm). Apical disc dicyclic with oculars well separated from periproct. Periproctal membrane with one large naked round plate (with conspicuous radial striation) and few very small additional plates. Genital plates with three to five spines and oval (elongated) pores. Peristome mostly naked except for the small buccal plates with few pedicellariae.Ambulacra with one primary tubercle per plate, occasionally slightly smaller than the corresponding one in the interambulacral plates, forming a more or less regular vertical series; bases of primary tubercles indented, particularly in the ambulacral areas. Ambulacral plates trigeminate with the pores forming a regular straight vertical series; pore-zones slightly sunken. Interambulacra presenting a single primary tubercle per plate forming a regular vertical series. Spines smooth relatively small (16–24%D). Globiferous pedicellaria with double poison glands and a single, tooth on one side beneath the terminal tooth. Colour: naked test green, brown or light brown with white spots just above the ambitus; spines hyaline, with red or pink bands; exceptionally white with traces of pink bands on some of the spines (DBUA-ECH 327).

Remarks: Mortensen (1927b) described a new extant Genocidaris species, G. splendens based on material collected by Talisman in the Canaries. This species differed from the typical G. maculata by its bright red colour, low test, the presence of a depression in the ambulacral (and interambulacral) midline aborally and a relative smaller suranal plate. In a later review, Mortensen (1943b) downgraded his species to a variety of G. maculata as all discussed diagnostic characters proved to be unreliable with both species presenting intermediate characters. Mortensen (1943b) concluded that G. splendens was at best just a colour variability of G. maculata . In spite of the great morphological variation revealed by the material herein examined we found no clear evidence that any of the specimens belong to the variety ‘ splendens ’. None had a particularly small suranal plate, a low test, or mid-line depressions. Regarding the colour pattern our material comprehended all possible transitions from the ‘typical’ olive through various shades of red. Our observations agree with Mironov (2006) who also questioned the validity of the variety ‘ splendens ’, based on animals from the Ormonde and Gorringe seamounts (NE Atlantic).

In the DBUA-ECH collection we have found a small white echinoid collected from the Sabrina Bank, SW of S„o Miguel Island (DBUA-ECH 327, Fig. 27 J–L). At first it was assumed to be the small echinoid Trigonocidaris albida , a species that also lives in the Azores at similar depths (see above). This species generally presents a white test with the distal edge of the apical disc light orange or greenish-yellow and white spines that aborally present a light red band just above the base. However, on closer examination we have found it to be a typical G. maculata with exception of its very unusual colour. Aside from the colour pattern, the specimen does not present many of the typical morphological characteristics of the genus Trigonocidaris or the species T. albida , such as a low test height (±50%D), buccal membrane covered by large imbricate plates or a periproct with four large angular plates (see Mortensen 1943b). On the contrary, the specimen presented a relatively high hemispherical test (=60%D), a naked buccal membrane with exception of the buccal plates and a peristome with a very large round and green suranal plate. Also, the test of DBUA-ECH 327 was not conspicuously ornamented as is typical observed in T. albida . The globiferous pedicellaria can be differentiated easily based on the poison glands, which are single in T. albida and double in G. maculata and in our white specimen (see Mortensen 1903, pl. 8, fig. 7). Though both species present globiferous pedicellaria with a single unpaired tooth beneath the terminal tooth, the ones of our white specimen look like typical G. maculata pedicellariae: a widened basal part with sharp corners, a very narrow blade (see Mortensen 1903, pl. 7, fig. 30).

Historically, G. maculata was mistakenly reported in the Azores by Agassiz (1872, as Tenmechinus maculatus ) based on material collected in the Josephine Seamount. Later, Agassiz (1881) identified the species Sphaerechinus granularis among the material collected by the H.M.S. Challenger in the Azores (sta 75: 38°37’N, 28°30’W), which later were re-identified by H.L. Clark (1925) as red coloured G. maculata (see also remarks under S. granularis ).

G. maculata is a small echinoid typical of low subtidal waters up to 500 m. However, among the material examined we have found one specimen (DBUA-ECH 155, Fig. 27 A–C) labelled as being collected in the intertidal waters of S„o Miguel Island. The possibility of mislabelling could not be overruled. However, the area where the specimen was collected is characterized by a sheltered and rather large tide-pool. Small animals of this species could survive among the crevices, algae or under the boulders in the relative protected waters of this tide-pool, in a similar fashion of the much larger echinoid Centrostephanus longispinus , also a typical deeper inhabitant of littoral waters but seen in waters as low as 5 m depth in some places in the Azores (see remarks under C. longispinus ). Conversely, Agassiz (1881) reported two different depths for the H.M.S. Challenger, station 75 where G. maculata was identified (92–165 m and 823 m), suggesting perhaps a mislabelling. Studying the known depth ranges of other echinoderms species also collected at this station we believe that shallower depth values are likely to be the correct ones (see remarks under Astropecten hermatophilus ).

Figures

FIGURE 27. Genocidaris maculata Agassiz, 1869 (DBUA-ECH 155: A–C; DBUA-ECH 151: D–F; DOP 3015: G–I; DBUA- ECH 327: J–L; DBUA-ECH 258: M–O). Aboral view (A, D, G, J, M); oral view (B, E, H, K, N); lateral view (C, F, I, L, O).