Amphipholis squamata ( Delle Chiaje, 1828 )

Silva, Jailma Ferreira Da, Christoffersen, Martin Lindsey & Prata, Jéssica, 2025, Diversity revealed: Ophiuroidea (Echinodermata) from reef ecosystems of Tropical Southwest Atlantic with new characters, Zootaxa 5689 (1), pp. 1-57 : 20-24

Amphipholis squamata ( Delle Chiaje, 1828)

Asteria squamata — Delle Chiaje 1828: 77.

Amphiura tenera — Rathbun 1879: 154.

Amphiura squamata — Lyman 1865: 122–123; Koehler 1913: 316.

Axiognathus squamatus — Lima-Verde 1969: 11; Boffi 1969: 450; 1972: 319; Tommasi 1970: 37, Fig. 36; 1974b: 188; Morgado & Tanaka 2001: 177.

Amphipholis squamata — Albuquerque 1986: 103, Fig. 18a–c , est. V, Fig. 1a–c ; Monteiro 1987: 60, Est. IIf; Tommasi & Aron 1987: 3; Manso & Absalão 1988: 79; Pires-Vanin et al. 1997: 36; Tommasi 1999; Borges 2001: 92, Fig. 1.47C,D ; 2006: 34; Borges et al. 2002: 44, Fig. 24 ; 2004: 157; Neto et al. 2005: 212; Borges & Amaral 2005: 261, Fig. A–D; Magalhães et al. 2005: 63; Gondim et al. 2008: 154; Majer 2008; Manso et al. 2008: 191, Fig. 18 e–g ; Veríssimo 2008: 40, Fig. 15A–F ; Barboza 2010: 15; Oliveira et al. 2010: 6; Lima et al. 2011: 6, Fig. 5B ; Barboza & Borges 2012: 11; Gondim et al. 2013a: 61 , Fig. 5 g –l ; 2013b: 511, Fig. 3C–D ; Paim et al. 2015: 5, Fig. 2D–F ; Alitto et al. 2016: 4, Fig. 3E–F ; Souto & Martins 2017: 305; 15; Prata et al. 2017: 3, Fig. 2 ; Bueno et al. 2018: 209, Fig. 46; Borrero-Perez et al. 2019: 191. Prata et al. 2020: 2, Fig. 3a–b .

Material examined: Mamanguape reefs, Rio Tinto, PB: 6°45'49.35"S 34°55'4.85"W, 2 spec. ( UFPB /ECH–2487); 2 spec. ( UFPB /ECH–2489); 5 spec. ( UFPB /ECH–2491); 27 spec. ( UFPB /ECH–2504); 6°45'54.0"S 34°55'04.0"W , 4 spec. ( UFPB /ECH–2512) ; 3 spec. ( UFPB /ECH–2513) ; 2 spec. ( UFPB /ECH–2514); 6°45'54.0"S 34°55'04.0"W , 4 spec. ( UFPB /ECH–2515). Formosa Beach, Cabedelo, PB: 6°58'55.5"S 34°48'55.3"W , 13 spec. ( UFPB /ECH–2531) ; 6 spec. ( UFPB /ECH–2532) ; 3 spec. ( UFPB /ECH–2534) ; 4 spec. ( UFPB /ECH–2537) ; 5 spec. ( UFPB /ECH–2538) ; 4 spec. ( UFPB /ECH–2539) ; 2 spec. ( UFPB /ECH–2540); 6º59'04.6"S 34º49'37.9"W, 1 spec. ( UFPB /ECH–2533); 6º58'38.8"S 34º48'57.4"W, 18 spec. ( UFPB /ECH–2535) ; 1 spec. ( UFPB /ECH–2536). Bessa Beach, João Pessoa, PB: 7°04'36.5"S 34°49'24.1"W , 11 spec. ( UFPB /ECH–2505) ; 23 spec. ( UFPB /ECH–2507) ; 14 spec. ( UFPB /ECH– 2508) ; 4 spec. ( UFPB /ECH–2509); 7º04'33.0"S 34º49'30.0"W, 2 spec. ( UFPB /ECH–2506) ; 4 spec. ( UFPB /ECH– 2511); 7°04'35.0"S 34°49'23.0"W, 31 spec. ( UFPB /ECH–2510). Cabo Branco Beach, João Pessoa, PB: 7º08'35.0"S 34º47'59.0"W , 7 spec. ( UFPB /ECH–2516) ; 1 spec. ( UFPB /ECH–2520); 7°08'41.1"S 34°47'43.9"W, 2 spec. ( UFPB / ECH–2517) ; 9 spec. ( UFPB /ECH–2518) ; 3 spec. ( UFPB /ECH–2519). Carapibus Beach, Conde, PB: 7º17'55.9"S 34º47'53.6"W, 2 spec. ( UFPB /ECH–2521); 1 spec. ( UFPB /ECH–2524); 1 spec. ( UFPB /ECH–2525) ; 7°18'03.0"S 34°47'53.0"W, 1 spec. ( UFPB /ECH–2522); 1 spec. ( UFPB /ECH–2523); 7°17'59.0"S 34°47'54.0"W, 9 spec. ( UFPB / ECH–2526); 2 spec. ( UFPB /ECH–2527); 4 spec. ( UFPB /ECH–2528); 2 spec. ( UFPB /ECH–2529); 7 spec. ( UFPB / ECH–2530). Tambaba Beach, Conde, PB : 7º21'59.1"S 34º47'51.4"W, 2 spec. ( UFPB /ECH–2541); 4 spec. ( UFPB / ECH–2542); 1 spec. ( UFPB /ECH–2543); 1 spec. ( UFPB /ECH–2545); 1 spec. ( UFPB /ECH–2546); 1 spec. ( UFPB / ECH–2548); 9 spec. ( UFPB /ECH–2549) ; 7º22'8.013"S 34°47'52.02W, 2 spec. ( UFPB /ECH–2544); 3 spec. ( UFPB / ECH–2547); 5 spec. ( UFPB /ECH–2550) ; 7°21'51.6"S 34°47'50.7"W, 1 spec. ( UFPB /ECH–2551) .

Description: specimen UFPB/ECH–2518. Circular disc ( dd = 2.58 mm and dh = 0.69 mm), covered, irregular, and imbricate scales. Large radial shield, longer than wide with the proximal edge slightly tapered and the distal curved, proximally separated by one or two small, triangular scales ( Figs. 11A, B ). Ventral interradial region covered by smaller scales that are more imbricated than the dorsal. Wide bursal slits, extending to the fourth ventral arm plate (VAP) ( Fig. 11C ). Oral shield diamond-shape, with the distal edge rounded. Large triangular adoral shield, joined at the proximal portion. Rectangular adoral shield spine, three to four times wider than long, and rounded secondary adoral shield spine, large infradental papillae ( Fig. 11D ). Five arms ( aw = 0.79 mm), about two to three times longer than the dd. Dorsal arm plate wider than long, with the distal edge slightly straight and the proximal rounded, separated by the lateral arm plates ( Figs. 11G ; 12C ). VAP longer than wide, the distal edge straight and the proximal tapered with lateral indentations ( Figs. 11H ; 12D, E ); small and triangular first ventral arm plate ( Fig. 11D ). Two small and triangular tentacle scale, arranged in parallel ( Fig. 11H ). Basal segments with four small and serrated arm spines, decreasing to three along the arm ( Figs. 11G, H ; 12I ).

Microstructures: oral plate wider than long, extensive abradial muscular area ( Fig. 11E ); adradial joint area defined, with striae in muscle insertion, large dorsal tentacle compartment and ventral tentacle compartment ( Fig. 11F ). Genital plates with large condyles (Cd) and deep groove in the inner region ( Fig. 12A ). Dental plate with three tooth sockets, without Septum, distal opening large and heart-shaped, the others smaller and circular, with large distal protruding knobs ( Fig. 12B ). Large lateral arm plate, little curved in the proximal region ( Fig. 12F ); inner portion with a large single perforation positioned in the ventral region ( Fig. 12G ); outer portion with three parallel and separated spine articulations ( Fig. 12H ). Vertebrae zygospondylous type: dorsal view vertebra with Cd fused, points distal aboral muscle fixation, proximal internal aboral muscle fixation and proximal external muscle fixation large, well developed, as well as the point of proximal oral muscle fixation ( Fig. 12J ); ventral view vertebra with long ventral groove, very deep and with some perforations ( Fig. 12K ); proximal ( Fig. 12L ) and distal ( Fig. 12M ) view vertebra with dorsal muscle area much bigger than ventral muscle area.

Intraspecific variations: in younger specimens, the primary plate is very evident, with a centro dorsal surrounded by eight overlapping primary scales, and the radial shield is wider than long, fully united, characteristics related to growth also described by Silva et al. (2023). Color whitish, but in some specimens, the coloration observed was dark brown, possibly due to the type of algae to which the specimens were found associated ( Figs. 11A, G ).

Taxonomic comments: the species has also been described with elongated and oval radial shield, united along their entire length and surrounded by imbricated scales ( Benavides-Serrato et al. 2011), dorsal arm plate more rounded, ventral arm plate with smaller indentation on the sides, lateral arm plate with smaller inner perforation ( Alitto et al. 2018), externally the LAPs do not touch in the ventral and dorsal region, two or three small sub-equal tentacle scale ( Prata et al. 2020). The vertebrae are very different from those described by Alitto et al. (2018 Fig. 15 J-M), in which dorsal-distal muscular fossae transformed distalwards projecting but far from distal edge of zygo -condyles and with a vertical oval hole through the ossicle, about half as long as the vertebra. According to those authors A. squamata is a species complex, that lacks more detailed morphological studies, with an extensive review on a geographic distribution, although the species is suspected to be undergoing reproductive isolation ( Alitto et al. 2018).

Morphometric variations: a total of 266 specimens were analyzed. Bigger dd: 2.58 mm, smaller dd: 0.55 mm. Average dd = 1.38 mm with sd = 0.43 mm, dh = 0.44 mm with sd = 0.16 mm, aw = 0.62 mm with sd = 2.55 mm and la = 2.77 mm with sd = 1.14 mm ( Table 5).

Substrate: the specimens were sampled in algae, polychaete tubes, under rhodoliths and in the sediment which was found next to the Ophionereis reticulata . This species is widely studied due to its cosmopolitan distribution and for inhabiting different substrates, such as sand, mud, algae, under rocks, sponges, corals and polychaete aggregates ( Paim et al. 2015; Alitto et al. 2018).

Bathymetric distribution: from the intertidal zone to 1330 m ( Hendler et al. 1995; Gondim et al. 2013a).

Geographic distribution: Cosmopolitan ( Tommasi 1970). In Brazil: Ceará ( Lima-Verde 1969), Paraíba in Cabo Branco Beach, Seixas and Barra de Mamanguape reefs ( Gondim et al. 2008; 2013a; Prata et al. 2017; 2020), Bessa Beach, Carapibus Beach, Formosa Beach and Tambaba Beach (present study), Alagoas ( 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).

Figures

FIGURE 1. External morphology of Ophiuroidea. (A) dorsal surface of the disc; (B) ventral surface of the disc; (C) jaws; (D) dorsal arm; (E) ventral arm. Abbreviations: 2°AdShSp: secondary adoral shield spine; AdSh: adoral shield; AdShSp: adoral shield spine; AP: accessory plate; ASp: arm spine; BS: bursal slits; BSc: bucal scale; DAP: dorsal arm plate; IPa: infradental papillae; LyOs: lyman’s ossicle; Mad: madreporite; OP: oral plate; Osh: oral shield; pp: primary plate; RS: radial shield; T: teeth; TSc: tentacle scale; VAP: ventral arm plate; VAP-1: first ventral arm plate.

FIGURE 2. Latitudinal distribution of sampling points along the coast of the State of Paraíba.Abbreviations: BB: Bessa beach; CB: Carapibus beach; CBB: Cabo Branco beach; FBR: Formosa beach reef; FBS: Formosa beach sand; MR: Mamanguape reefs; TB: Tambaba beach.

FIGURE 3. Ophioderma appressum (Say, 1825). (A) dorsal disc; (B) ventral disc; (C) jaw; (D) madreporite; (E) adoral shield; (F) dorsal arm; (G) ventral arm.Abbreviations: 2°AdShSp: secondary adoral shield spine; AdSh: adoral shield; AdShSp: adoral shield spine; BS: bursal slits; DAP: dorsal arm plate; DASp: dorsalmost arm spine; IPa: infradental papillae; LOPa: lateral oral papillae; LyOs: Lyman’s ossicle; Mad: madreporite; Osh: oral shield; SP: spur; TPa: tooth papillae; TSc: tentacle scale; VAP: ventral arm plate; VAP-1: first ventral arm plate; VASp: ventral most arm spine. Specimen UFPB/ECH–2446.

FIGURE 5. Ophionereis reticulata (Say, 1825). (A) dorsal disc; (B) ventral disc; (C) jaw; (D) oral plate external; (E) oral plate internal; (F) dorsal arm; (G) ventral arm. Abbreviations: 2°AdShSp: secondary adoral shield spine; Abja: abradial joint area; Abma: abradial muscle area; Adja: adradial joint area; Adma: adradial muscle area; AdSh: adoral shield; AdShSp: adoral shield spine; AP: accessory plate; BS: bursal slits; BSc: bucal scale; DAP: dorsal arm plate; DASp: dorsalmost arm spine; dTCt: dorsal tentacle compartment; IPa: infradental papillae; LyOs: Lyman’s ossicle; Mad: madreporite; OPrs: Oral plate ridge spine; Osh: oral shield; Rc: radial channel; RS: radial shield; TSc: tentacle scale; VAP: ventral arm plate; VAP-1: first ventral arm plate; VASp: ventral most arm spine; vTCt: ventral tentacle compartment. Specimen UFPB/ECH-2438.

FIGURE 11. Amphipholis squamata (Delle Chiaje, 1828). (A–B) dorsal disc; (C) ventral disc; (D) jaw; (E) oral plate external; (F) oral plate internal; (G) dorsal arm; (H) ventral arm.Abbreviations: 2°AdShSp: secondary adoral shield spine; Abja: abradial joint area; Abma: abradial muscle area; Adja: adradial joint area; Adma: adradial muscle area; AdSh: adoral shield; AdShSp: adoral shield spine; BS: bursal slits; DAP: dorsal arm plate; DASp: dorsalmost arm spine; dTCt: dorsal tentacle compartment; IPa: infradental papillae; Mad: madreporite; OPrs: Oral plate ridge spine; Osh: oral shield; pp: primary plate; Rc: radial channel; RS: radial shield; TSc: tentacle scale; VAP: ventral arm plate; VAP-1: first ventral arm plate; VASp: ventral most arm spine; vTCt: ventral tentacle compartment. Specimen UFPB/ECH–2518.

FIGURE 12. Amphipholis squamata (Delle Chiaje, 1828) internal structures. (A) genital plates; (B) dental plate; (C) dorsal arm plate; (D–E) ventral arm plate; (F–H) lateral arm plate; (I) arm spine; (J) dorsal vertebra view; (K) ventral vertebra view; (L) proximal vertebra view; (M) distal vertebra view. Abbreviations: Cd: condyles; Damf: distal aboral muscle fixation; Deomf: distal oral external muscle fixation; Doimf: distal oral internal muscle fixation; pe: perforation; Peamf: proximal external muscle fixation; Piamf: proximal internal aboral muscle fixation; Pk: protruding knobs; Pomf: proximal oral muscle fixation; Sa: spine articulation; Ts: tooth sockets; Vg: ventral groove. Specimen UFPB/ECH–2518.

FIGURE 15. Ophiophragmus luetkeni (Ljungman, 1872). (A) dorsal disc; (B) ventral disc; (C) jaw; (D) oral plate external; (E) oral plate internal; (F) adoral shield; (G) dorsal arm; (H) ventral arm. Abbreviations: 2°AdShSp: secondary adoral shield spine; Abja: abradial joint area; Abma: abradial muscle area; Adja: adradial joint area; AdSh: adoral shield; AdShSp: adoral shield spine; BS: bursal slits; DAP: dorsal arm plate; DASp: dorsalmost arm spine; dTCt: dorsal tentacle compartment; IPa: infradental papillae; Mad: madreporite; OPrs: Oral plate ridge spine; Osh: oral shield; Rc: radial channel; ribs: rib-like branching structures; RS: radial shield; TSc: tentacle scale; VAP: ventral arm plate; VAP-1: first ventral arm plate; VASp: ventral most arm spine; vTCt: ventral tentacle compartment. Specimen UFPB/ECH–2456.

FIGURE 18. Ophiactis lymani Ljungman, 1872 internal structures. (A) dental plate; (B) dorsal arm plate; (C) ventral arm plate; (D–F) lateral arm plate; (G) arm spine; (H) dorsal vertebra view; (I) ventral vertebra view; (J) proximal vertebra view; (K) distal vertebra view. Abbreviations: Damf: distal aboral muscle fixation; Ddmf: dorso-distal muscular fossae; Deomf: distal oral external muscle fixation; Dg: dorsal groove; Doimf: distal oral internal muscle fixation; pe: perforation; Pomf: proximal oral muscle fixation; Sa: spine articulation; Ts: tooth sockets; Vg: ventral groove. Specimen UFPB/ECH–2460.

FIGURE 24. Ophiothrix brasiliensis Santana, Manso, Almeida & Alves, 2020 internal structures. (A–B) disc spines with denticles; (C–D) dental plate; (E) tooth; (F) dorsal arm plate; (G) ventral arm plate; (H–J) lateral arm plate; (K) arm spine; (L) dorsal vertebra view; (M) ventral vertebra view; (N) proximal vertebra view; (O) distal vertebra view. Abbreviations: Ddmf: dorso-distal muscular fossae; Dg: dorsal groove; Dma: dorsal muscle area; pe: perforation; Pk: protruding knobs; S: septum; Sa: spine articulation; Ts: tooth sockets; TPas: tooth papillae sockets; Vg: ventral groove; Vma: ventral muscle area; Zd: zygocondyle; Zp: zygosphene. Specimen UFPB/ECH–2455.