Figure 1.
A, Collection localities of Acyrtus material examined as part of this investigation.
Color of symbols correspond to clades in B. Open symbols represent type localities. B, Strict consensus of 479 equally parsimonious cladograms (1102 steps; CI = 0.391; RI = 0.681) resulting from parsimony analysis of COI data set. Numbers above branches represent bootstrap support values.
Table 1.
Means of corrected genetic distances within and between three genetic lineages of Acyrtus based on COI sequence data.
Table 2.
Summary of differences among the four species of Acyrtus.
Figure 2.
Acyrtus lanthanum, new species.
A, holotype, FMNH 84325, 14.0
Figure 3.
Recently collected specimens of Acyrtus and Arcos.
A, Acyrtus lanthanum, new species, USNM 404171, 16.5 mm SL, DNA # BLZ 10171, Belize. B, Acyrtus artius, USNM 404205, 19.0 mm SL, DNA # BLZ 10205, Belize. C, Acyrtus rubiginosus, USNM 404174, 10.5 mm SL, DNA # BLZ 10174, Belize. D, Arcos nudus, USNM 403507, 49.7 mm SL, DNA# ELU 1003, Bahamas. Photographs A-C by Donald Griswold and Carole Baldwin; D by Louis Johnson, edited by authors.
Figure 4.
Ventral view of head (A–B), subopercular region of left side (D–F), and subopercle from right side in medial view (G–J) in members of Acyrtus and Arcos.
A, Acyrtus lanthanum, new species, holotype, FMNH 84325, 14.0 mm SL. B, Acyrtus artius, ANSP 123658, 15.2 mm SL. C, Arcos nudus, ANSP 115602, 25.6 mm SL. D, Close up of subopercular region of left side in A. E, Close up of subopercular region of left side in B. F, Close up of subopercular region of left side in C. G, Acyrtus lanthanum, new species, ANSP 106336, 20.4 mm SL. H, Acyrtus rubiginosus, UF 149202, 20.0 mm SL. I, Acyrtus artius, ANSP 94757, 24.2 mm SL. J, Arcos nudus, ANSP 142945, 27.0 mm SL. White asterisks indicate posteriormost tip of subopercular spine in D–E. Abbreviations: BR, branchiostegal ray; GSop, groove in subopercle; Sop, subopercle; VGS, venom gland cells. Scale bars equal to 1 mm (A–C, F) or 400 µm (D–E, G–J).
Table 3.
Select measurements for Acyrtus lanthanum, new species, A. artius and A. rubiginosus.
Table 4.
Select meristic characters for four species of Acyrtus (A. lanthanum, new species, A. artius, A. pauciradiatus and A. rubiginosus) and Arcos nudus.
Figure 5.
Suspensorium (right side in lateral view; images reversed) in members of Acyrtus.
A, Acyrtus lanthanum, new species, UF 212697, 18.0 mm SL. B, Acyrtus artius, ANSP 123658, 18.0 mm SL; dorsal head of quadrate damaged. C, Acyrtus rubiginosus, UF 149202, 20.0 mm SL. Abbreviations: Ang, anguloarticular; Den, dentary; Ect, ectopterygoid; Hyo, hyomandibular; Iop, interopercle; Max, maxilla; Op, opercle; Pal, autopalatine; Pmax, premaxilla; Pop, preopercle; Ret, retroarticular; Sop, subopercle; Sym, symplectic; Q, quadrate. Scale bars equal to 1 mm.
Figure 6.
External surface (A–C) and skeletal structure (D–F) of the adhesive disc in members of Acyrtus.
A, Acyrtus lanthanum, new species, ANSP 106336, 20.4 mm SL. B, Acyrtus artius, ANSP 94757, 24.2 mm SL. C, Acyrtus rubiginosus, UF 149202, 20.0 mm SL. D, Acyrtus lanthanum, new species, UF 212697, 18.0 mm SL; head of right pelvic-fin spine damaged. E, Acyrtus artius, ANSP 123658, 18.0 mm SL; anterior margin of left basipterygium damanged. F, Acyrtus rubiginosus, UF 149202, 20 mm SL. Letters A-C in A refer to disc regions as defined by Briggs (1955). Abbreviations in D: B, basipterygium; I, pelvic-fin spine; VP, ventral postcleithrum; 1–4, pelvic-fin rays 1–4. Scale bars equal to 500 µm (A–C) or 1 mm (D–F).
Figure 7.
A, holotype, CAS-SU 23254, 18.4 mm SL, Curacao. B, FMNH 84329, 15.4 mm SL, Belize. C, ANSP 106336, 20.4 mm SL, Bahamas. Photographs in A by Jon Fong (CAS).
Figure 8.
Sections through the subopercular region in species of Acyrtus and Arcos.
A, Acyrtus artis, ANSP 106336, 19.0 mm SL. B, Arcos nudus, ANSP 94773, 37.1 mm SL. C, Acyrtus lanthanum, new species, ANSP 81310, 19.5 mm SL. D, Acyrtus rubiginosus ANSP 106128, 18.0 mm SL. E, close up of subopercular spine; same specimen as in A. F, close up of subopercular spine; same specimen as in B. G, close up of subopercular spine; same specimen as in C. H, close up of subopercular spine; same specimen as in D. I, Close up of box in A, showing cells of venom gland. J, Close up of box in B, showing cells of venom gland. Abbreviations: BaLa, basal lamina of epidermis; BR, branchiostegal ray; CC, club cell; Ederm, epidermis; GSop, groove in subopercle; MC, mucus cell; Op, opercle; PBM, pocket in branchiostegal membrane; SEderm, sloughed epidermis; Sderm, subdermis; Sop, subopercle; VG, venom gland; VGC, venom gland cell. Scale bars equal to 500 µm (A–D) or 100 µm (E–J).