Phylogenetic Relationships within the Stingray Genus Dasyatis (Chondrichthyes: Dasyatidae)
Phylogenetic relationships for 14 of 35 currently recognized Dasyatis species (Dasyatis americana, Dasyatis brevis, Dasyatis centroura, Dasyatis geijskesi, Dasyatis guttata, Dasyatis kuhlii, Dasyatis lata, Dasyatis longus, Dasyatis margaritella, Dasyatis pastinaca, Dasyatis sabina, Dasyatis say, Dasyatis violacea, and Dasyatis zugei), Pastinachus sephen (sometimes referred to as Dasyatis sephen), one Indo-West Pacific Himantura (Himantura gerrardi), and four outgroups (Gymnura micrura, Urobatis jamaicensis, Taeniura lymma, and amphi-American Himantura schmardae) were elucidated using parsimony analysis of 32 morphological characters. One most-parsimonious tree of 116 steps (CI = 0.345, HI = 0.655, RI = 0.64) was found. The analysis refutes monophyletic Dasyatis and Himantura and reveals Dasyatis kuhlii, D. violacea, and P. sephen to be basal among other ingroup species, with D. kuhlii as the most basal species. The genus Himantura is paraphyletic, with amphi-American H. schmardae as sister to a clade containing all species except Urobatis jamaicensis. Himantura gerrardi is nested well within Dasyatis as sister to D. margaritella and forms a clade with G. micrura and Dasyatis zugei. Sister species Dasyatis geijskesi and D. guttata form a clade with D. zugei, G. micrura, D. margaritella, and H. gerrardi. This clade is sister to a group containing sister pairs of D. centroura/D. lata and D. longus/D. americana. Dasyatis brevis and D. say are sister species. Neotropical Dasyatis are polyphyletic.Abstract
Disc shapes. (A) Dasyatus geijskesi, (B) Dasyatus americana, and (C) Dasyatus violacea. In this figure and all subsequent figures, numbers represent characters and character states
Most-parsimonious tree generated for 20 species from 32 characters. Bootstrap values and decay indices (in parentheses) are left of branches. Numbers to right of branches indicate number of characters supporting that node. Nonhomoplastic characters are in bold next to number of characters. Letters left of branches represent the following character changes, with states in parentheses and nonhomoplastic characters in bold: A = 32(1); B = 5(2), 20(1), 24(1), 27(2), 31(1); C = 8(1), 10(1), 18(1), 26(1); D = 17(1), 21(1), 24(0), 25(2); E = 2(1), 8(2), 15(2), 31(0); F = 3(1), 4(2), 14(1), 23(1); G = 10(0), 12(1), 24(1), 31(1); H = 22(1); I = 1(1), 3(2), 11(1), 15(1), 26(0); J = 4(1), 5(1), 6(1), 7(1), 16(1), 20(0), 28(1); K = 1(0), 3(1), 22(1); L = 9(1), 18(0); M = 4(0), 10(1), 23(0), 26(1); N = 14(2), 19(1), 29(1), 30(1); O = 9(1), 21(0); P = 6(0), 18(0), 23(0); Q = 1(0), 4(0), 5(0), 7(0), 10(1), 20(1), 27(1); R = 12(0), 13(1), 19(0), 25(0); S = 5(2), 21(0); T = 13(1), 27(1); U = 21(0), 24(0); V = 16(0); W = 13(1), 15(0), 24(0), 27(1); X = 20(1), 22(1); Y = 16(0), 28(0); Z = 2(0), 15(2), 17(0); Aa = 5(1), 6(1), 23(1), 27(0), 30(0); Bb = 3(1), 9(1), 14(1), 25(1), 28(0), 31(0); Cc = 2(0), 3(0); Dd = 21(0); Ee = 7(1); Ff = 25(0); Gg = 5(1), 11(1), 18(0), 19(1), 20(0), 28(1); Hh = 4(2), 15(1), 23(1); Ii = 6(1), 13(1), 14(1), 17(1). Some ray silhouettes after Garman (1913), Bigelow and Schroeder (1953), Eschmeyer et al. (1983), and Compagno and Roberts (1984)
Pelvic girdle. (A) Dasyatus brevis (MCZ–371), (B) Hemantura gerrardi (FMNH 21839), and (C) Dasyatus geijskesi (USNM 158726). Abbreviation: PP, prepelvic process
Left pectoral girdle and anterior portion of neurocranium. (A) Dasyatus kuhlii (FMNH 40915), (B) Dasyatus violacea (ANSP 386, syntype), (C) Himantura. gerrardi (FMNH 21839), and (D) Dasyatus geijskesi (USNM 158726). Abbreviations: AO, antorbital cartilage; MS, mesopterygium; MT, metapterygium; NC, nasal capsule; PR, propterygium; SC, scapulocoracoid
Fontanelle of neurocranium. (A) Dasyatus kuhlii (FMNH 40915), (B) Dasyatus lata (MCZ–129), and (C) Dasyatus geijskesi (USNM 158726)
Right mandibular arch. (A) Dasyatus kuhlii (FMNH 40915), (B) Dasyatus brevis (MCZ–371), and (C) Dasyatus violacea (ANSP 386, syntype). Abbreviations: MC, Meckel's cartilage; PQ, palatoquadrate
Medial plate and basihyal of branchial arches. (A) Dasyatus guttata (MCZ–313), (B) Dasyatus violacea (ANSP 386, syntype). Abbreviations: BH, basihyal; MP, medial plate