Ophiactis savignyi ( Müller & Troschel, 1842 )

Ophiactis savignyi ( Müller & Troschel, 1842) View in CoL

Ophiolepis savignyi — Müller & Troschel 1842: 95, pl. 2, Fig. 4–5 View FIGURE 4 View FIGURE 5 .

Ophiactis virescens View in CoL — Lutken 1856: 24.

Ophiactis krebsii View in CoL — Verrill 1868: 366.

Ophioactis savignii — Krau 1950: 358.

Ophiactis savignyi View in CoL — Brito 1960: 4, Fig. 3 View FIGURE 3 ; 1962: 2; Lima-Verde 1969: 12; Boffi 1969: 450; 1972: 319; Tommasi 1970: 24, Figs. 16–17 View FIGURE 16 View FIGURE 17 ; 1999; Nunes 1975: 181; Albuquerque 1986: 150, Fig. 25a–c View FIGURE 25 , est. VIII, Fig. 2a–c View FIGURE 2 ; Monteiro 1987: 34, Est. If, IIa,b;1997: 183; Manso & Absalão 1988: 79; Albuquerque & Guille 1991: 8; Manso 1993: 191; Pires-Vanin et al. 1997: 36; Alves & Cerqueira 2000: 545; Morgado & Tanaka 2001: 177; Borges et al. 2002: 367 Fig. 21E–D View FIGURE 21 ; Borges et al. 2004: 157; Neto et al. 2005: 213; Borges & Amaral 2005: 250, Fig. A–D; Magalhães et al. 2005:63; Borges 2006: 61, Fig. 1.18 View FIGURE 1 ; Clavico et al. 2006; Ventura et al. 2006:351; Ventura & Veríssimo 2007d: 240, Fig. A–E; Neves et al. 2007: 1265; Gondim et al. 2008: 154; Majer 2008; Manso et al. 2008: 188, Fig. 14f–h View FIGURE 14 ; Lima & Fernandes 2009: 61; Oliveira et al. 2010:6; Lima et al. 2011: 6, Fig. 4D View FIGURE 4 ; Barboza & Borges 2012: 10; Miranda et al. 2012: 138; Gondim et al. 2013a: 70 View Cited Treatment , Fig. 8 g –l View FIGURE 8 ; 2013b: 513, Fig. 4C–D View FIGURE 4 ; Paim et al. 2015: 10, Fig. 6D–F View FIGURE 6 ; Alitto et al. 2016: 12, Fig.5G–H View FIGURE 5 ; Souto & Martins 2017: 306; Prata et al. 2017: 4, Fig. 5 View FIGURE 5 ; Bueno et al. 2018: 218, Fig. 59; Borrero-Perez et al. 2019: 191.

Material examined: Barra de Mamanguape reefs, Rio Tinto, PB: 6°45'49.35"S 34°55'4.85"W, 2 spec. ( UFPB / ECH–2488) GoogleMaps ; 3 spec. ( UFPB /ECH–2490) GoogleMaps ; 6°45'54.0"S 34°55'04.0"W, 2 spec. ( UFPB /ECH–2497) GoogleMaps ; 1 spec. ( UFPB / ECH–2498) GoogleMaps ; 1 spec. ( UFPB /ECH–2499) ; 7 spec. ( UFPB /ECH–2502) ; 13 spec. ( UFPB /ECH–2503). Formosa Beach, Cabedelo, PB : 6°58'55.5"S 34°48'55.3"W, 3 spec ( UFPB /ECH–2496) GoogleMaps ; 6º58'38.8"S 34º48'57.4"W, 1 spec. ( UFPB /ECH–2501) GoogleMaps ; 6º58'54.0"S 34º49'02.0"W; 1 spec. ( UFPB /ECH–2501) GoogleMaps ; 2 spec. ( UFPB /ECH–2492). Bessa Beach, João Pessoa, PB : 7º04'33.0"S 34º49'30.0"W, 2 spec. ( UFPB /ECH–2493) GoogleMaps ; 2 spec. ( UFPB /ECH–2500) GoogleMaps ; 7°04'35.0"S 34°49'23.0"W, 1 spec. ( UFPB /ECH–2495). Carapibus Beach, Conde, PB GoogleMaps : 7°17'59.0"S 34°47'54.0"W, 1 spec. ( UFPB /ECH–2494) GoogleMaps .

Description: specimen UFPB/ECH–2492. Circular disc ( dd = 2.54 mm and dh = 1.18 mm), dorsally covered, irregular, overlapping scales. Approximately eight small blunt spines surround the central scales. The edge of the disc is also surrounded by small spines ( Figs 19A, B View FIGURE 19 ). Large triangular radial shield, occupying almost half of the dd, longer than wide and separated at the proximal edge by two scales ( Fig. 19B View FIGURE 19 ). Ventral interradial region with smaller scales than dorsal ones. Wide bursal slits, extending to the third arm segment. Rounded madreporite ( Fig. 19C View FIGURE 19 ). Jaw with a diamond-shaped oral shield. Triangular adoral shield, longer than wide and united at the proximal edge. Spatulate and elongated adoral shield spine, smaller secondary adoral shield spine ( Fig. 19D View FIGURE 19 ). Six arms ( aw = 1.18 mm) about two to three times longer than the dd. Rounded dorsal arm plate ( Figs 19G View FIGURE 19 ; 20C View FIGURE 20 ). Square ventral arm plate, with rounded distal region, proximal with slight indentation and expanded lateral region ( Figs 19H View FIGURE 19 ; 20D View FIGURE 20 ); triangular first ventral arm plate ( Fig. 19D View FIGURE 19 ). A large and spatulate tentacle scale ( Fig. 19H View FIGURE 19 ). Basal lateral arm plate with five denticulate arm spines, decreasing to four along the arm, the dorsalmost arm spine most pointed and the second most large ( Figs 19G, H View FIGURE 19 ; 20H View FIGURE 20 ).

Microstructures: oral plate longer than it is wide, with abradial muscular area well defined, long radial channel ( Fig. 19E View FIGURE 19 ); adradial joint area with the narrow and striated muscle insertion area; large dorsal tentacle compartment and ventral tentacle compartment ( Fig. 19F View FIGURE 19 ). Dental plate with three tooth sockets, the proximal ones bigger, separated by protruding knobs and without Septum ( Fig. 20A View FIGURE 20 ), large teeth, as long as wide, with short, smooth and flat distal portion ( Fig. 20B View FIGURE 20 ). Lateral arm plate convex in the proximal region ( Fig. 20E View FIGURE 20 ); inner portion with a single perforation ( Fig. 20F View FIGURE 20 ); outer portion with four spine articulations ( Fig. 20G View FIGURE 20 ). Vertebrae zygospondylous type: vertebra dorsal view with medial portion V-shaped, slightly deep dorsal groove ( Fig. 20I View FIGURE 20 ); vertebra ventral view with wide, elongated, and deep ventral groove ( Fig. 20J View FIGURE 20 ); vertebra proximal view ( Fig. 20K View FIGURE 20 ) with dorsal muscular area ( Fig. 20L View FIGURE 20 ) much larger than ventral view and distal view vertebra with dorsal muscle area well developed.

Intraspecific variations: in younger specimens the central disc scales are larger, however, the number of spines is less in comparison with the disc diameter. These spines can be scattered or restricted to the disc edge. Dorsal arm plate (DAP) is triangular, the ventral arm plate rectangular and the lateral arm plate with the arm spine more denticulated. Some young specimens have gone through fission, causing some differences, and specimens with only three structures radial shield (RS), three arms, oral papillae, and plates. At the regeneration site, the disc does not show the RS, just scales and some arm buds, in the ventral region, they also lack the oral shield and oral ossicles, even after complete regeneration the arms may be disproportionate in length and width. The color of the disc with central scales and radial shields is greenish, interradial scales, the distal edge of the RS, and the ventral surface of the disc are whitish. The DAPs intercalate between greenish and whitish plates ( Figs 19A, G View FIGURE 19 ).

Taxonomic comments: the species has also been described with radial shield fully united and with two scales in the proximal region ( Borges et al. 2002; Paim et al. 2015), trapezoidal dorsal arm plate, longer than wide, octogonal ventral arm plate, with tapered proximal portion ( Tommasi 1970; Alitto et al. 2018), an oral papillae on each side of the jaw, six arm spine ( Gondim et al. 2013a), pores in the middle region of madreporite ( Borges et al. 2002), vertebra distal view with short zygocondyle ( Alitto et al. 2018).

Morphometric variations: a total of 43 specimens were analyzed. Bigger dd: 2.54 mm, smaller dd: 0.63 mm. The general average of the dd = 1.32 mm with sd = 0.46 mm, dh = 0.56 mm with sd = 0.24 mm, aw = 0.69 mm with sd = 0.22 mm and la = 2.85 mm with sd = 1.18 mm ( Table 9).

Substrate: the specimens were collected from algae, rhodoliths, and sponges. Young specimens tend to inhabit the interior of sponges, possibly due to positive stereotropism ( Tommasi 1970), being common within sponges of Haliclona sp. ( Lima & Fernandes 2009). They can also be found in sediments ( Manso et al. 2008), mud bottoms, under rocks ( Paim et al. 2015), in marine phanerogams banks, mangrove areas and contaminated communities ( Hendler et al. 1995).

Bathymetric Distribution: from the intertidal zone to 518 m ( Tommasi 1970; Hendler et al. 1995; Gondim et al. 2013a).

Geographic distribution: Cosmopolitan species, with wide geographical distribution ( Tommasi 1970). In Brazil: Maranhão ( Gondim et al. 2013b), Ceará ( Lima-Verde 1969), Paraíba in the Cabo Branco Beach and Seixas reefs ( Gondim et al. 2008; 2013a; Prata et al. 2017), Barra de Mamanguape reefs, Bessa Beach, Carapibus Beach and Formosa Beach (present study), Pernambuco ( Lima & Fernandes 2009), Alagoas ( Oliveira et al. 2010; Lima et al. 2011; Miranda et al. 2012) and Bahia ( Alves & Cerqueira 2000; Magalhães et al. 2005; Manso et al, 2008; Paim et al. 2015; Souto & Martins 2017).