New Species of Squatina (Squatiniformes: Squatinidae) from Brazil, with Comments on the Taxonomy of Angel Sharks from the Central and Northwestern Atlantic
Morphological analysis of South- and Northwestern Atlantic specimens of Squatina revealed an undescribed species of angel shark occurring on the continental slope of Brazil between latitudes 11° and 22°S. The new species of Squatina is distinguished from western Atlantic congeners by a unique combination of dorsal color pattern, vertebral counts, morphology of lateral dermal folds, dermal denticles, female reproductive tract, clasper, and pectoral fin characters. A preliminary assessment of the taxonomy of angel shark species from the Central and Northwestern Atlantic is also provided. A análise morfológica de espécimes de Squatina do Atlântico Sudoeste e Noroeste revelou uma espécie não descrita de cação anjo ocorrendo no talude continental do Brasil entre as latitudes 11° e 22°S. A nova espécie de Squatina distingue-se de seus congêneros do Atlântico Oeste por uma combinação única do padrão de coloração dorsal, contagem de vértebras, morfologia das dobras dérmicas laterais, do trato reprodutivo feminino, do clásper e da nadadeira peitoral. Uma análise preliminar sobre a taxonomia das espécies de cação anjo do Atlântico Central e Noroeste é adicionalmente incluída.
Holotype of Squatina varii, MNRJ 43106 (adult male, 1110 mm TL, continental slope of Espírito Santo state, Brazil, Southwestern Atlantic) in dorsal (A) and ventral (B) views; and paratype MNRJ 43101 (adult male, 1215 mm TL, continental slope of Espírito Santo state, Brazil, Southwestern Atlantic Ocean) in dorsal view (C). Scale bar = 100 mm.
Paratypes of Squatina varii, MNRJ 43105 (adult female, 1320 mm TL, continental slope of Espírito Santo state, Brazil, Southwestern Atlantic Ocean) in dorsal (A) and ventral (B) views; and MNRJ 43108 (adult female, 1084 mm TL, continental slope of Bahia state, Brazil, Southwestern Atlantic) in dorsal view (C). Scale bar = 100 mm.
Paratypes of Squatina varii, MNRJ 42112 (sub-adult male, 981 mm TL, continental slope of Sergipe state, Brazil, Southwestern Atlantic) in dorsal (A) and ventral (B) views. (C) Dorsal view of fresh specimen of Squatina varii (photo credit: M. Senna). Scale bar = 100 mm.
Morphological details of Squatina varii in holotype MNRJ 43106 (A, C–F) and paratype MNRJ 43105 (B). (A, B) Dorsal view of head. (C) Ventral view of head and pectoral region. (D) Ventral view of pelvic fins. (E) Lateral view of dorsal fins. (F) Lateral view of caudal fin. Scale bar = 40 mm.
Morphological details of Squatina varii in holotype MNRJ 43106 (A, B), paratype MNRJ 43105 (C), and paratype MNRJ 43109 (D). Anterior (A) and posterior (B) nasal flaps in frontal view. (C, D) Lateral wall of the head in ventro-lateral view. Ventral region of the head presented in gray to highlight the shape of the lateral dermal folds, which are shown in color. Arrows indicate the rounded lobe on anterior third of the lateral dermal fold. Scale bar = 10 mm.
Clasper external morphology of Squatina varii in holotype MNRJ 43106 (A, B) and paratype MNRJ 43107 (C, D). (A) Dorsal aspect of the left clasper. (B–D) Details of the clasper glans. In (D), the cover rhipidion is spread to show morphological details of the spermatic duct. Abbreviations: cg, clasper groove; crh, cover rhipidion; hyp, hypopyle; psp, pseudopera; rh, rhipidion. Arrows indicate the width of the cover rhipidion. Anterior to top. Scale bar = 10 mm.
Morphology of dermal denticles of Squatina varii. Dermal denticles of paratype MNRJ 30190 (juvenile female) from the dorsal surface of post-orbital region (A) and from the dorsal surface of the posterior region of dorsal midline (B). (C–F) Dermal denticles of the outer edge of the pectoral fin, showing sexual dimorphism. (C, D) Paratype MNRJ 43101 (adult male) of Squatina varii in dorsal (C) and dorso-lateral close-up (D). (E, F) Dermal denticles of paratype MNRJ 43105 (adult female) of Squatina varii in dorsal (E) and dorso-lateral close-up (F). Anterior to top (A, B) and to left (C–F).
Clasper skeleton of Squatina varii (MRNJ 43104, adult male, continental slope of Espírito Santo state, Brazil) in dorsal (A, B) and ventral views (C, D). Abbreviations: acd, accessory dorsal marginal cartilage; ax, axial cartilage; dm, dorsal marginal cartilage; dt1, dorsal terminal cartilage; dt2, dorsal terminal 2 cartilage; gcr, globular cartilaginous rod; pvr, pelvic radials; stj, stem-joint cartilages; vm, ventral marginal cartilage; vt1, ventral terminal cartilage; vt2, ventral terminal 2 cartilage. Anterior to top. Scale bar = 10 mm.
Map of Southwestern Atlantic showing the geographic distribution of Squatina varii. Star depicts holotype locality. Circles represent paratype localities. Localities may represent more than one specimen. Abbreviations: AL, Alagoas state; BA, Bahia state; ES, Espírito Santo state; RJ, Rio de Janeiro state; RS, Rio Grande do Sul state; SE, Sergipe state; SP, São Paulo state.
Species and morphological forms of Squatina from Central and Northwestern Atlantic. (A) Squatina dumeril (USNM 410798, juvenile male, 320 mm TL, North Carolina, USA; Northwestern Atlantic). (B) Squatina david (USNM 400796, juvenile male, 325 mm TL, Panama, Central Atlantic). (C) Squatina sp. NW1 (USNM 118461, juvenile female, 390 mm TL, Northwestern Atlantic). Scale bar = 50 mm.
Contributor Notes
Associate Editor: D. Buth.