Amphipholis januarii Ljungman, 1866

Amphipholis januarii Ljungman, 1866 View in CoL

Amphipholis januarii —Ljungman 1866: 165–166.

Amphipholis pachybactra View in CoL — Clark 1918: 284, Fig. 3–5 View FIGURE 3 View FIGURE 4 View FIGURE 5 ; Clark 1933: 49; Thomas 1962: 657–660, Fig. 11 View FIGURE 11 .

Amphipholis januarii View in CoL — Rathbun 1879: 155; Tommasi 1967: 1–2, Fig. 1 View FIGURE 1 ; Lima-Verde 1969: 11; Manso 1993: 193; Magalhães et al. 2005: 63; Gondim et al. 2008: Manso et al. 2008: 190, Fig. 18 A–D View FIGURE 18 ; 154; Lima et al. 2011: 6, Fig. 5A View FIGURE 5 ; Miranda et al. 2012: 139; Barboza & Borges 2012: 11; Gondim et al. 2013a: 59 View Cited Treatment , Fig. 5a–f View FIGURE 5 ; 2013b: 511, Fig. 3A–B View FIGURE 3 ; Paim et al. 2015: 3, Fig. 2A–D View FIGURE 2 ; Alitto et al. 2016: 4, Fig. 3C–D View FIGURE 3 ; Souto & Martins 2017: 305; Prata et al. 2017: 3, Fig. 3 View FIGURE 3 ; Bueno et al. 2018: 208, Fig. 45; Borrero-Perez et al. 2019: 191; Prata et al. 2020: 4, Fig. 3c–d View FIGURE 3 .

Material examined: Formosa Beach , Cabedelo, PB : 6º58'38.8"S 34º48'57.4"W, 2 spec. ( UFPB /ECH–2483). Bessa Beach, João Pessoa, PB GoogleMaps : 7º04'33.0"S 34º49'30.0"W, 15 spec. ( UFPB /ECH–2481). Carapibus Beach, Conde, PB GoogleMaps : 7°18'03.0"S 34°47'53.0"W, 1 spec. ( UFPB /ECH–2479) GoogleMaps ; 2 spec. ( UFPB /ECH–2480) GoogleMaps ; 1 spec. ( UFPB /ECH–2485) ; 1 spec. ( UFPB /ECH–2486) ; 7°17'59.0"S 34°47'54.0"W, 2 spec. ( UFPB /ECH–2482) GoogleMaps ; 1 spec. ( UFPB /ECH–2484) GoogleMaps .

Description: specimen UFPB/ECH–2482. Circular disc ( dd = 3.71 mm and dh = 1.14 mm), with slight indentations at the interradial region, covered dorsally by imbricate scales, almost uniform. Radial shield longer than wide, rounded distal edge, tapered proximal edge separated by a small scale. Disc bordered by rows of aligned scales ( Figs. 9A, B View FIGURE 9 ). Ventral interradial region covered by small and more imbricate fine scales than the dorsal. Wide bursal slits extending to the fourth or fifth ventral arm plate (VAP) ( Fig. 9C View FIGURE 9 ). Jaw with diamond shape oral shield (arrowhead) tapered proximal and distal edge. Large and rounded madreporite ( Fig. 9E View FIGURE 9 ). Triangualar adoral shield, commonly joined at the proximal edge ( Figs. 9D, E View FIGURE 9 ). Adoral shield spine triangular, large, wider than long, secondary adoral shield spine rounded, with one rounded infradental papillae ( Fig. 9E View FIGURE 9 ). Five arms ( aw = 1.41 mm), about four times longer than the dd. Dorsal arm plate much wider than long, with a straight proximal region ( Figs. 9H View FIGURE 9 ; 10D View FIGURE 10 ). Pentagonal VAP, with straight distal edge and pointed proximal edge ( Figs. 9I View FIGURE 9 ; 10E View FIGURE 10 ); square first ventral arm plate ( Fig. 9E View FIGURE 9 ). Two large and perpendicular tentacle scale ( Fig. 9I View FIGURE 9 ). The basal segments with four arm spines, decreasing to three along the arm, of which the middle one has denticles ( Figs. 9H, I View FIGURE 9 ; 10I View FIGURE 10 ).

Microstructures: wider than long oral plate, well-defined abradial muscular area with rib-like branching structures ( Fig. 9F View FIGURE 9 ); adradial joint area with narrow muscular insertion area, with evident stretch marks; dorsal tentacle compartment larger than ventral tentacle compartment, with a deep indentation ( Fig. 9G View FIGURE 9 ). Elongated dental plate, a proximal region with a straight edge and rounded distal, outer portion has eight tooth sockets, with protruding knobs on their sides and separated by Septum ( Figs 10A; B View FIGURE 10 ); longer than wide teeth, distal region with a smooth and flat surface ( Fig. 10C View FIGURE 10 ). The lateral arm plates ( LAP ) extend to half of the dorsal arm plate. LAP with proximal region C-shaped ( Fig. 10F View FIGURE 10 ); inner portion with a single perforation, positioned in the ventral region ( Fig. 10G View FIGURE 10 ); outer portion with three spine articulations ( Fig. 10H View FIGURE 10 ). Vertebrae zygospondylous type: ventral view vertebra with deep ventral groove in the middle region, with four muscular fossaes well defined ( Fig. 10J View FIGURE 10 ); proximal ( Fig. 10K View FIGURE 10 ) and view distal ( Fig. 10L View FIGURE 10 ) vertebra with dorsal muscle area much bigger than the ventral muscle area.

Intraspecific variations: in younger specimens, it is possible to observe the primary plate. As the specimen grows, the dorsal scales tend to be arranged more uniformly, becoming smaller and less overlapping. In some individuals, the radial shield is narrower and separated at the proximal edge by three scales. Color whitish ( Fig. 9A View FIGURE 9 ).

Taxonomic comments: the species was also described with the separated radial shield (RS) in the anterior region by two to four scales, of which the inner one is elongated ( Tommasi 1970), evident primary plate, separated RS by one or two scales, distally separated adoral shield ( Paim et al. 2015), a little more curved lateral arm plate, ventral view vertebra with less deep Vs and less evident zygocondyle ( Alitto et al. 2018 Fig. 14H, I View FIGURE 14 ).

Morphometric variations: a total of 25 specimens were analyzed. Bigger dd: 3.71 mm, smaller dd: 1.22 mm. Average of dd = 2.22 mm with sd = 0.60 mm, dh = 0.64 mm with sd = 0.19 mm, aw = 0.91 mm with sd = 0.22 mm, and la = 6.74 mm with sd = 2.71 mm ( Table 4).

Substrate: the specimens were sampled under rocks, rhodolites and commonly associated with algae in when young stage. They can also be found in thin sand, shell, and muddy bottoms ( Tommasi 1970), marine phanerogam banks ( Hendler et al. 1995), sponges and cnidarians ( Paim et al. 2015).

Bathymetric distribution: from intertidal zone to 55 m ( Hendler et al. 1995; Gondim et al. 2013a).

Geographic distribution: South Carolina, Florida, Texas, Cuba, Puerto Rico, Virgin Islands, Barbados, Tobago, Brazil ( Tommasi 1970, Hendler et al. 1995). In Brazil: Maranhão ( Gondim et al. 2013b), 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 and Formosa Beach (presente estudo), Alagoas ( Lima et al. 2011; Miranda et al. 2012), Sergipe ( Oliveira et al. 2010) and Bahia ( Alves & Cerqueira 2000; Magalhães et al. 2005; Manso et al. 2008; Paim et al. 2015; Souto & Martins 2017).