Isostichopus badionotus (Selenka, 1867)

Figs 1A–J, 3A–D, 4A, 5A, 6–9, 10A, 11A; Tables 1–3

Stichopus badionotus Selenka, 1867: 316, pl. 18 fig. 20.

Stichopus haytiensis Semper, 1868: 75, pl. 30 fig. 5.

Stichopus möbii Semper, 1868: 246, pl. 40 fig. 11.

Stichopus errans Ludwig, 1875: 97 .

Stichopus diaboli Heilprin, 1888: 312 .

Stichopus xanthomela Heilprin, 1888: 313 .

Stichopus acanthomella – H.L Clark in Lloyd 1900: 885. Typographic error.

Stichopus badionotus – Clark 1922: 55, pl. 2 figs 11–18; 1933: 109; 1942: 386. — Deichmann 1930: 80, pl. 5 figs 30–36; 1940: 195; 1954: 388, fig. 66, 1–8; 1957: 4, figs 1–4.

Stichopus moebii – Clark 1922: 55. — Cutress 1996: 105. Article 32.5.2.1 ICZN Code (1999).

Isostichopus badionotus – Deichmann 1958: 280; 1963: 106. — Tikasingh 1963: 84, figs 23–25. — Pawson 1976: 373. — Caycedo 1978: 159, pl. 1 figs 1–4. — Miller & Pawson 1984: 54, figs 44–45. — Hendler et al. 1995: 280, figs 156, 187g –i. — Cutress 1996: 105, figs 33B–D, 37–40, table 13. — Pawson et al. 2010: 34, figs 6f, 27. — Borrero-Pérez et al. 2012: 174, 175, figs b, c, e–o; 2022: 180–186. — Prata et al. 2014: 143, fig. 7a–h, table 5. — Vergara & Rodríguez 2015: 1022, fig. 1a. — Martínez et al. 2016: 19–20, figs 2, 4. — Vergara et al. 2018: 36–39, figs 2–3. — Acosta et al. 2021: 1–17. — Purcell et al. 2023: 142–143.

Stichopus herrmanni – Rodríguez-Forero et al. 2013: 12, fig. 5.

Stichopus hermanni – Vergara & Rodríguez 2015: 1022, fig. 1c. Typographic error.

Original name

Stichopus badionotus Selenka, 1867 .

Current status

Isostichopus badionotus (Selenka, 1867) .

Name-bearing type

Lectotype MCZ HOL-509.

Type locality

Florida, USA.

Diagnosis

No spiral lines in dorsal and lateral papillae; four color patterns (Figs 1A–J, 8); no worm-like rod ossicles in dorsal papillae (Fig. 7A); mtDNA divergence from other species of the genus>6.1% in COIFr1 (barcoding region),>10.8% in COI-Fr2 and> 5.2% in 16S (Table 2).

Material examined

Lectotype (here designated)

USA • 1 reticulated color pattern (L = 190 mm); Florida; collector number 395 leg.; MCZ HOL-509.

Other material

NORTH ATLANTIC – Bermuda • 2 specs uniform pattern (L = 170–230 mm); Harrington Sound; 32.330556° N, 64.721944° W; 11 Jul. 1911; E.M. Grosse leg.; MCZ HOL-1082 • 1 spec. chips pattern (L = 205 mm); Harrington Sound; 32.330556° N, 64.721944° W; 1911; E.M. Grosse leg.; MCZ HOL-1083 • 1 spec. juvenile (L = 40 mm); Bailey’s Bay; 11 Oct. 1972; depth 2–3 m; D.L. Pawson leg.; USNM E11783. – Bahamas • 1 spec. uniform pattern? (L = 145 mm); North Bimini, Lerner Marine Lab; 3 Jun. 1959; R.U. Gooding and A.G. Humes leg.; MCZ HOL-4301. – USA • 1 spec. chips pattern (L = 166 mm); South Carolina, Racoon Key; 3 Jul. 1963; depth 46 m; A.S. Merril leg.; USNM E9808 • 1 spec. chips pattern (L = 130 mm); Georgia; 30.8967° N, 80.6067° W; 20 Aug. 1980; depth 33 m; Georgia Marine Resources for Minerals Management Service leg.; USNM E27835 • 1 spec. chips pattern (L = 250 mm); Florida, 56.5 nautical miles off NE Inlet; 30.18° N, 80.25° W; 27 Apr. 1983; depth 64 m; W.G. Lyons leg.; USNM E33178 .

GULF OF MEXICO – USA • 1 spec. chips pattern (L = 210 mm); Florida, Sanibel Island; 26.440359° N, 82.113705° W; Mar. 1938; A.C. Fenner Jr leg.; MCZ HOL-1876 • 1 spec. reticulated pattern (L = 230 mm); Florida, Florida Keys, Dry Tortugas, Bird Key; 24.6185° N, 82.8854° W; Jun. 1917; H.L. Clark leg.; MCZ HOL-1212 • 1 spec. uniform pattern (L = 130 mm); Florida, Florida Keys, Dry Tortugas, Garden Key; 28 Sept. 1982; depth 2 m; J.E. Miller leg.; USNM E27982 • 1 spec. chips pattern (L = 257 mm); NW of Florida Keys; 24.7853° N, 83.2181° W; 20 Nov. 1980; depth 58.6 m; Mote Marine Lab for BLM/MMS leg.; USNM E40637 • 1 spec. uniform pattern (L = 255 mm); Florida, West of Naples; 25.7656° N, 82.1558° W; 12 Feb. 1982; depth 19.6 m; Continental Shelf Associes for BLM/ MMS leg.; USNM E39240 • 1 spec. uniform pattern (L = 250 mm); Florida, West of Fort Myers; 26.2803° N, 82.7336° W; 3 May 1981; depth 30.4 m; Continental Shelf Associes for BLM/MMS leg.; USNM E40334. – Mexico • 2 specs; Veracruz, Isla Sacrificios; 26 Jan. 1957; M.E. Caso leg.; ICML-UNAM 5.14.10 • 2 specs; Veracruz, Isla de En medio, Anton Lizardo; 19.1088889° N, 95.934445° W; 11 Jun. 2004; depth 1.5 m; P. Rodríguez leg.; on sandy bottom; ICML-UNAM 5.14.45 • 1 spec.; Veracruz, Isla Sacrificios; 19.2916667° N, 96.158056° W; 6 Apr. 2005; depth 1–2 m; J. Díaz leg.; on sandy bottom; ICML-UNAM 5.14.46 • 1 spec.; Veracruz, Bajos de Tuxpan; 21.0271667° N, 97.199° W; 15 Mar. 2011; depth 4–5 m; F. Solís-Marín leg.; coral reef; ICML-UNAM 5.14.58 • 1 spec.; Veracruz, off Isla Lobos; 21.4726667° N, 97.231167° W; 17 Mar. 2011; depth 12 m; F. Solís-Marín leg.; coral reef; ICML-UNAM 5.14.59 • 1 spec.; Veracruz, off Isla Lobos, Capirotes; 21.484° N, 97.228667° W; 17 Mar. 2011; depth 6–14 m; F. Solís-Marín leg.; coral reef; ICML-UNAM 5.14.60 • 1 spec.; Veracruz, El Morro de Punta Delgada; 19.8568333° N, 97.4565° W; 19 Mar. 2011; depth 1 m; F. Solís-Marín leg.; rocky bottom; ICML-UNAM 5.14.61 • 1 spec.; Tabasco, Paraíso Beach, Escollera Oeste; 29 Mar. 1998; M. Dominguez leg.; ICML-UNAM 5.14.41 • 1 spec.; Campeche, Sound of Campeche; Jun. 1972; ICML-UNAM 5.14.36 • 1 spec.; Campeche, Sound of Campeche; Jun. 1978; ICML-UNAM 5.14.37 • 3 specs; Campeche; 19.1716667° N, 91.648333° W; 13 Feb. 1995; ICML-UNAM 5.14.38 • 1 spec.; Campeche, Ciudad del Carmen, Bahamita Beach; 1 Aug. 1972; M.E. Caso leg.; ICML-UNAM 5.14.39 • 1 spec.; Campeche, Ciudad del Carmen, Las Playuelas Mou; 27 Nov. 1973; M.E. Caso leg.; ICML-UNAM 5.14.40 • 1 spec.; Yucatán, Arrecife Alacranes; 22.3871389° N, 89.6843612° W; 1 Aug. 2009; depth 2 m; Q. Hernandez leg.; ICML-UNAM 10736 • 1 spec.; Yucatán, Dzilan de Bravo, Yalkulub lighouse; 22.3980556° N, 88.8875° W; 21 May 2015; depth 14–18 m; A. Poot. leg.; sandy bottom; ICML-UNAM 11094 • 1 spec.; Yucatán, Celestun; 20.8597222° N, 90.4391667° W; 23 Apr. 2010; depth 3 m; S. Rodríguez leg.; sandy bottom; ICML-UNAM 18301 .

CARIBBEAN SEA – Mexico • 3 specs; Yucatán, Yucalpeten; 21.3522222° N, 89.711111° W; 14 Dec. 2000; depth 5 m; Z. Moguel leg.; ICML-UNAM 5.14.16 • 11 specs; Yucatán, San Felipe; 21.55° N, 89.6° W; 22 Oct. 2000; depth 1.5 m; Z. Moguel leg.; ICML-UNAM 5.14.26 • 2 specs; Quintana Roo, North of Cabo Coche; 22.6566667° N, 87.2083333° W; 28 Apr. 1985; depth 54.5 m; M.E. Caso leg.; ICML-UNAM 5.14.7 • 1spec.; Quintana Roo, Puerto Morelos; 20.8745833° N, 86.8506944° W; 17 Aug. 1999; depth 6 m; S. Frontana leg.; ICML-UNAM 5.14.42 • 1 spec.; Quintana Roo, Puerto Morelos, Bocana Chica; 20.8804083° N, 86.8509611° W; 3 Aug. 2009; depth 5.3 m; F. Solís-Marín leg.; ICML-UNAM 5.14.57. – Belize • 1 spec. reticulated pattern (L = 185 mm); Southwater Cay, West Side; 4 May 1974; K. Sandved leg.; USNM E18633. – Honduras • 1 spec. chips pattern (L = 180 mm); West of Vivario Cays; 15.7233° N, 83.4833° W; 1 Feb. 1971; depth 29 m; leg.; USNM 1014372 • 1 spec.; Cayos Cochinos; Apr. 1998; depth 6 m; C.R. Hasbun leg.; on muddy bottom; ICML-UNAM 5.14.48. – Panama • 1 spec. reticulated pattern; Bocas del Toro, Cayo Adriana; 9.240528° N, 82.173417° W; 30 May 2013; depth 15 m; G. Borrero and A. Castillo leg.; mixed bottom sand, sponges, rubble coral, coral, algae and isolated seagrass, exposed, IbBT2R; Tiss-IbBT2 • 1 spec. chips pattern (L = 166 mm); same data as for preceding; IbBT14CH; USNM 1659459 • 1 spec. chips pattern; same data as for preceding; IbBT16CH; Tiss-IbBT16 • 1 spec. reticulated pattern (L = 200 mm); same data as for preceding; IbBT20R; USNM 1659460 • 1 spec. uniform pattern (L = 240 mm); same data as for preceding; depth 5 m; IbBT45U; USNM 1659461 • 1 spec. uniform pattern (L = 130 mm); same data as for preceding; depth 5 m; IbBT48U; USNM 1659462 • 1 spec. chips pattern (L = 185 mm); same data as for preceding; depth 10 m; IbBT55CH; USNM 1659463 • 1 spec. chips pattern (L = 240 mm); Bocas del Toro, Punta STRI; 9.3488889° N, 82.2616667° W; 30 May 2013; depth 6 m; G. Borrero and A. Castillo leg.; sandy bottom, exposed, IbBT62CH; USNM 1659464 • 1 spec. black and yellow pattern; same data as for preceding; IbBT67BY; Tiss-IbBT67 • 1 spec. reticulated pattern (L = 226 mm); same data as for preceding; IbBT69R; USNM 1659464 • 1 spec. black and yellow pattern; same data as for preceding; IbBT71BY; Tiss-IbBT71 • 1 spec. black and yellow pattern; same data as for preceding; IbBT73BY; Tiss-IbBT73 • 1 spec. black and yellow pattern (L = 180 mm); same data as for preceding; IbBT75R; MBMLP IbBT75 • 1 spec. reticulated pattern; same data as for preceding; IbBT83R; Tiss-IbBT83 • 1 spec. chips pattern (L = 135 mm); Bocas del Toro, STRI research station 1; 9.3502778° N, 82.25722222° W; 28 May 2013; depth 4 m; G. Borrero and I. Pedroarena-Leal leg.; seagrass bed, exposed, IBT106CH; MBMLP-IBT106 • 1 spec. chips pattern (L = 202 mm); same data as for preceding; IBT107CH; USNM 1659467 • 1 spec. chips pattern (L = 195 mm); same data as for preceding; IbBT111CH; USNM 1659454 • 1 spec. chips pattern (L = 210 mm); same data as for preceding; IbBT115CH; USNM 1659456 • 1 spec. chips pattern (L = 205 mm); same data as for preceding; IbBT118CH; USNM 1659458 • 1 spec. reticulated pattern (L = 130 mm); Bocas del Toro, STRI research station 2; 9.3488611° N, 82.2585° W; 28 May 2013; depth 5 m; G. Borrero and I. Pedroarena-Leal leg.; mixed bottom of sand, corals, sponges, and isolated seagrass, exposed, IbBT98R; USNM 1659466 • 1 spec. uniform pattern (L = 230 mm); same data as for preceding; IbBT112U; USNM 1659455 • 1 spec. black and yellow pattern (L = 235 mm); same data as for preceding; IbBT116BY; USNM 1659457. – Colombia • 1 spec. reticulated pattern; Magdalena, Santa Marta, Punta Betín; 11.250582° N, 74.220133° W; 23 May 2012; depth 3 m; G. Borrero and J. Gómez leg.; sandy, rocky bottom, exposed, IbSM4R; INV-TEJ1167 • 1 spec. reticulated pattern; same data as for preceding; IbSM5R; INV-TEJ1168 • 1 spec. reticulated pattern; same data as for preceding; IbSM7R; INV TEJ1170 • 1 spec. reticulated pattern; same data as for preceding; IbSM9R; INV TEJ1172 • 1 spec. reticulated pattern; same data as for preceding; IbSM10R; INV TEJ1173 • 1 spec. black and yellow pattern; same data as for preceding; IbSM13BY; INV TEJ1176 • 1 spec. reticulated pattern; same data as for preceding; IbSM15R; INV TEJ1178 • 1 spec. chips pattern; Magdalena, Parque Nacional Natural Tayrona, Nenguanje; 11.2500542° N, 74.1633922° W; 24 May 2012; depth 6 m; G. Borrero and E. Acosta leg.; IbNe1CH; INV TEJ1179 • 1 spec. chips pattern; same data as for preceding; IbNe6CH; INV TEJ1184 • 1 spec. chips pattern; same data as for preceding; IbNe15CH; INV TEJ1193 • 1 spec. chips pattern; same data as for preceding; IbNe16CH; INV TEJ1194 • 1 spec. chips pattern; same data as for preceding; IbNe18CH; INV TEJ1196 • 1 spec. chips pattern (L = 140 mm); La Guajira, El Pajaro, Tawaya; 11.7308333° N, 72.7099167° W; 9 Sep. 2013; depth 4.1 m; E. Ortíz and J. López leg.; IbGV93CH; INV TEJ1267 • 1 spec. chips pattern (L = 130 mm); same data as for preceding; IbGV100CH; INV TEJ1268 • 1 spec. uniform pattern (L = 210 mm); La Guajira, El Pajaro, Tawaya; 11.7547778° N, 72.7045833° W; 10 Sep. 2013; depth 4.5 m; E. Ortíz and J. López leg.; IbGV155U; INV TEJ1292 • 1 spec. reticulated pattern (L = 135 mm); same data as for preceding; IbGV157R; INV TEJ1294 • 1 spec. reticulated pattern (L = 180 mm); same data as for preceding; depth 6.8 m; IbGV236R; INV TEJ1301 • 1 spec. chips pattern (L = 220 mm); La Guajira, Manaure, Piedras Blancas; 11.8251389° N, 72.4600833° W; 28 Sep. 2013; depth 9.2 m; E. Ortíz and J. López leg.; IbGV250CH; INV TEJ1306 • 1 spec. chips pattern (L = 115 mm); same data as for preceding; IbGV300CH; INV TEJ1310 • 1 spec. chips pattern (L = 190 mm); La Guajira, Manaure; 11.96030556° N, 72.57925° W; 5 Apr. 2005; depth 50 m; N. Cruz-Macrofauna-Corpoguajira Project leg.; sandy bottom, IbEQU3046CH; INV EQU3046 • 1 spec. chips pattern (L = 200 mm); La Guajira, Manaure; 11.8778333° N, 72.790361° W; 4 Apr. 2005; depth 54 m; N. Cruz-Macrofauna-Corpoguajira Project leg.; sandy bottom, INV EQU3047; GenBank: INV EQU3047 • 1 spec. chips pattern; La Guajira, Manaure; 11.327184° N, 74.081037° W; 29 Oct. 2011; depth 7 m; G. Borrero and C. Díaz leg.; sandy bottom, IbMa10CH; INV TEJ1125 – Venezuela • 1 spec. chips pattern (L = 160 mm); USNM E11411. – Curaçao • 1 spec. black and yellow pattern; 12.170247° N, 69.039721° W; IbCu1BY; Tiss-IbCu1 • 1 spec. uniform pattern; 12.170247° N, 69.039721° W; leg.; IbCu2U; Tiss-IbCu2. – Cuba • 1 spec. chips pattern (L = 210 mm); 1914; J.B. Henderson and P. Bartsch leg.; USNM 34802. – Jamaica • 1 spec. chips pattern (L = 150 mm); Portland Bight; 17.8367° N, 77.11° W; 5 Jul. 1970; depth 13 m; leg.; USNM 1014365. – Puerto Rico • 1 spec. uniform pattern (L = 50 mm); La Parguera, Enrique reef; 26 Apr. 1986; C.E. Cutress leg.; USNM E43381 • 1 spec. reticulated pattern (L = 160 mm); La Parguera, Enrique reef; Nov. 1986; C.E. Cutress leg.; USNM E43382. – British Virgin Islands • 1 spec. uniform pattern (L = 160 mm); Guana Island; Jul. 1999; A.M. Kerr leg.; USNM E51775 • 1 spec. juvenile (L = 55 mm); Guana Island; depth 2 m; A.M. Kerr leg.; USNM E47522. – Antigua and Barbuda • 1 spec. uniform pattern (L = 280 mm); Antigua Island, English Harbor; 17° N, 61.7667° W; Jul. 1918; C.C. Nutting, State University of Iowa leg.; USNM E41459 .

SOUTH ATLANTIC – Brazil • 1 spec.; Santa Catalina, Island of Arvoredo; 27.273601° S, 48.366889° W; IbBr1; Tiss-IbBr1, only tissue • 1 spec.; same data as for preceding; IbBr9; Tiss-IbBr9, only tissue • 1 spec.; Santa Catalina, Desert Island; 27.273601° S, 48.366889° W; IbBr6; Tiss-IbBr6, only tissue • 1 spec.; same data as for preceding; IbBr15; Tiss-IbBr15, only tissue .

Description

EXTERNAL APPEARANCE. Preserved and live ex situ specimens, up to 300 mm long, range of examined specimens 40–240 mm (n = 39, lectotype: 190 mm long). Body loaf-like, length/width ratio 4± 0.7 (n = 18, 2.5–5.9, lectotype 2.5). Rounded posteriorly and anteriorly (Fig. 6), convex or somewhat quadrangular in cross-section (Fig. 8); largest specimens usually quadrangular. Body wall firm and thick (2–6 mm thick in the lectotype). Anus supra-terminal, circular and surrounded by large papillae. Mouth directed ventrally, encircled by collar of large papillae (3–4 mm high in the lectotype). Large peltate tentacles 20, up to 10–12 mm long, with shields 7–10 mm wide. Dorsal and lateral papillae variable in size, shape, and organization. Dorsal papillae wart-like, rounded, and low or flat with only one pointed tip, scattered irregularly in convex specimens or in two irregular rows along each flank defining the quadrangular shape (Fig. 8). Lateral papillae large and stout, conical, pointed or rounded, or forming a continuous fringe (Fig. 8), sharply defining the ventral surface. Dorsal body wall of the lectotype deteriorated, but with some medium size papillae (up to 1–2 mm high and 3–6 mm wide at the base), not conspicuous; most of the papillae in the lectotype in the two dorso-lateral rows (Fig. 6A). Ventral surface covered with numerous cylindrical and large pedicels arranged in three longitudinal rows (Fig. 6B).

COLOR AND BODY WALL APPEARANCE. The body wall in living specimens is smooth and opaque in adults longer than 130 mm (Figs 1A–J, 8). Dorsal coloration extremely variable; four main color patterns (Figs 1, 8): (1) Chips color pattern (CH) (Fig. 1A–D): the most common, light or dark brown, pink, orange background, with scattered darker spots of variable size, rounded or irregular, and separated or joined. in blotches; the species owes one of its common names “chocolate chip sea cucumber” to this coloration. (2) Uniform color pattern (U) (Fig. 1E): uniformly brown, orange, pink, yellowish, or black; some with darker papilla tips. (3) Reticulated color pattern (R) (Fig. 1F–I): beige background with a darker brown reticulum, which may also appear as small beige irregular spots on a darker brown background; papillae inside the reticulum, darker with yellow or beige sharply pointed tips, and dark brown rings at the base. (4) Black and yellow color pattern (BY) (Fig. 1J): black background with large yellow rounded or low and pointed papillae. Ventral coloration also highly variable, uniformly of the same color as the dorsal side, or spotted, or blotched. Specimens in alcohol always lighter, but color pattern retained. Lectotype brown with a clear “Reticulated” color pattern in the best preserved areas; papillae, shield of tentacles, ventral surface, and pedicels same color as the background; stalk of tentacles lighter (Fig. 6A–B). Juveniles (40–50 mm) with semi-translucent body wall, and of similar color as the adults (Fig. 8R–U, F’).

INTERNAL ANATOMY (based on MCZ HOL-509, lectotype; USNM 1659462; USNM 1659459; USNM 1659454 and USNM 1659457, specimens 130–230 mm long). Calcareous ring of lectotype 14 mm in diameter, radial elements roughly quadrangular, 7 mm wide and 7 mm long, with four small anterior lobes; two dorsal radial plates with long posterior projections (3–4 mm long) turned inwards; the three ventral radial plates with shorter posterior projections than the two dorsal plates; interradial elements, 5 mm wide and 2 mm long, less wide than radial elements, shorter than half the length of radial elements, pointed anteriorly with a concave posterior margin (3.5 mm long) (Fig. 4A). Posterior projection in the dorsal radial plates lengthens during growth and turnes inwards in the largest specimens, as described in the lectotype (Fig. 4A). Stone canal in the lectotype irregularly helical, about 22 mm long, including a flat leaf-like madreporite 6 mm at its longest diameter, attached to the mesentery, partially calcified, and ending in a point. Single stone canal similar to lectotype in shape in other examined specimens (L(body length) = 130 mm: 5 mm long; L = 230 mm: 21 mm). Tentacle ampullae in the lectotype about 20–25 mm long and 1 to 2.5 mm wide, with small branches at the tips and the bases, increasing with size in other specimens (L = 130 mm: ampullae = 2 mm; L = 230 mm: ampullae = 21 mm). Single Polian vesicle about 24 mm long by 5 mm wide in the lectotype; similar in other examined specimens (L = 130 mm: 11 mm long by 3 mm wide; L = 230 mm: 19 mm by 5 mm). Gonad in two tufts, one on either side of dorsal mesentery, branched in numerous cylindrical tubes about 0.5–1.5 mm wide, extending 85 mm from the anterior to the posterior body and filled with eggs 72–99 µm diameter in the lectotype (Fig. 11A). Gonads present in specimens from 130 mm long. Longitudinal muscles divided, about 10 to 12 mm wide in the lectotype, attached to body wall medially and unattached laterally. Respiratory trees inserted near the anterior part of the cloaca, arising from a 16 mm long common stem in the lectotype. Right tree about 100 mm long, left tree about 110 mm, extending along the intestine. Similar respiratory trees in other specimens, with the right branch shorter than the left.

OSSICLES (based on MCZ HOL-509, lectotype, for mouth membrane and gonads, other ossicles deteriorated; USNM 1659462; USNM 1659454 (SEM images); USNM 1659457 and USNM E11783 (juvenile, only for dorsal papillae), specimens 40–230 mm long).

Dorsal papillae with tables, thin C-shaped rods, perforated plates, and large, curved rods (Figs 7A, 10A). Numerous C-shaped deposits, fewer S-shaped, 52–130 (x = 80) µm, usually present in the papillae, especially towards the tip, variable in abundance in different papillae of the same specimen. Length of C-shaped deposits increasing with body length (Fig. 9A). Numerous table ossicles 33–70 (x = 52) μm high and 39–81 (x = 58) µm across the disc; spires composed of four pillars, usually parallel or slightly constricted proximally to the disc, ending in triplets of blunt spines forming a wide crown, one crossbeam connecting adjacent pillars. Table spire of 40 mm long juvenile with many minute spines. Disc margins smooth and wide; discs with one rounded central perforation and 8 to 12 peripheral holes, usually arranged in one simple ring (Figs 7A, 10A). Tables close to the tip of the papillae larger, taller, and with wider discs, with several extra perforations arranged in more than one ring, becoming smaller and with fewer perforations toward the base of the papillae where they are similar to those from the body wall (Fig. 10A). Small changes of tables in size and shape during growth; but tables with shorter spire in the 40 mm specimen (33–41 μm high; x = 37) than in other examined sizes (42–70 μm high; x = 58) (Figs 9B, 10A); disc tables in smaller specimens wider than in larger ones (Figs 9C, 10A), usually with more than 8–10 holes arranged in more than one ring; in larger specimens disc tables typically with 8–12 holes set in one ring (Fig. 10A). Few perforated plates (112–179 µm), located at the tip of the papillae, with a few large perforations, larger at the center of the plate (Fig. 7A); not found in the 40 mm specimen. Large, curved rods (240–493 µm) with quadrangular occasionally perforated projections in the middle (Fig. 7A).

Dorsal body wall with only tables and a few C-shaped ossicles (63–83 µm), less frequent than in papillae, rarely S-shaped (Fig. 7A). Tables similar in shape as in papillae but smaller 47–62 (x = 54) μm high, 39–69 (x = 49) µm across the disc, the discs with one ring of 8–12 holes (Fig. 10A).

Pedicels with tables, thin C-shaped rods, perforated plates, large, slightly or strongly curved rods, and end plates (Fig. 7B). A few specimens also with a few C-shaped, rarely S-shaped, deposits 70–95 (x = 85) µm. Numerous table ossicles 24–42 (x = 34) μm high and 25–72 (x = 53) µm across the disc, less high than those from dorsal papillae and the dorsal body wall, similar in shape to the ones from the dorsal papillae, but with the central perforation usually larger and not rounded, with four points that sometimes interrupt the simple ring of holes in the disc, usually one ring of holes, with no extra perforations (Fig. 7B). Numerous elongated perforated plates (174–432 µm), with numerous perforations larger and elongated in the center of the plate; large slightly or strongly curved rods (316–483 µm) with broad perforated expansions in the middle; end plates 687 µm across, increasing in size during growth.

Ventral body wall with only tables and a few C-shaped ossicles.

Tentacles with rods and tables (Fig. 7C). A few table ossicles similar to those from the dorsal body wall 40–56 μm high and 40–73 µm across the disc; numerous strongly or slightly curved spiny rods (37–804 µm), sometimes with perforations at the ends.

Mouth membrane with C-shaped ossicles, large tables, and rods in some specimens (Figs 7D, 11A). Thin 43–102 µm C-shaped rods and numerous large tables 89–160 µm high and 100–159 µm across the disc. Large tables with the spire well developed, composed of at least ten pillars that are joining at the top, forming a very dense and thick crown of spines, without crossbeams connecting adjacent pillars, lateral edges of the external pillars usually with pointed projections. Table discs generally wide with several rings of holes; sometimes reduced, same width as the spire in 130 mm specimen (Figs 7D, 11A); large tables taller and more slender in the 130 mm long specimen, 166–271 µm heigh, whereas 125–188 µm high in specimens 195 and 230 mm long.

Longitudinal muscles with thin C-shaped rods 40 to 85 (x = 58) µm long and small, simple 59–145 (x = 112) µm rods (Fig. 7E). Posterior cloaca with numerous C-shaped rods (48–73 µm), simple rods (74–131 µm), and spinous irregular plate-like branched rods (Figs 7F, 11A); anterior cloaca with large and complex tables 105–140 µm high and 139–180 µm across the disc (Fig. 11A). Respiratory trees with few tables 46–55 µm high and 45–56 µm across the disc in the 130 and 195 mm long specimens, but not in the 230 mm long one (Fig. 7G). Intestine with spinose or smooth 43–110 µm rods in a cross shape, sometimes with bifurcated ends (Fig. 7H). Gonads with delicate, long rods 449–775 µm (Fig. 7I). Rods in the gonads present even in the 130 mm long specimen. Gonads of the lectotype with rods 301–452 µm long (Fig. 11A).

Distribution

Western Atlantic, from Bermuda and North Carolina, USA to Santa Catarina, South Brazil, including the Gulf of México and the Caribbean Sea (Fig. 5A). The geographic range of I. badionotus as defined here is restricted to the Western Atlantic, where it is sympatric with I. maculatus phoenius currently confirmed in the Gulf of Mexico and the Caribbean Sea, and with I. macroparentheses reported from some locations in the Gulf of Mexico and the Caribbean Sea. The southernmost record of I. badionotus in Santa Catarina, Brazil, was confirmed by mitochondrial DNA (Fig. 3C–D). It has been reported from the Brazilian coast and nearby islands, in São Sebastião, the northeast coast of Brazil, and the Trindade and Martin Vaz Archipelago by Netto et al. (2005), Netto (2006), Prata et al. (2014) and Martins et al. (2016), whose photographs depict I. badionotus . Bathymetric distribution 0–183 m (USNM E39041). The species is common between 0– 30 m.

Habitat

Isostichopus badionotus is common and abundant. Field observations have recorded juveniles of I. badionotus on seagrass (Shiell 2004) and attached to the underside of rubble or coral slabs (Clark 1933; Hendler et al. 1995; Conand 2006), although some of these reports may include juveniles of I. maculatus phoenius . The species is found on muddy, sandy, sandy-muddy, rocky substrates, seagrass beds, mostly Thalassia testudinum K.D. Koenig, and mixed bottoms (sand, corals, algae, sponges, and scattered seagrass). As a distinctive characteristic of I. maculatus phoenius, individuals larger than 130 mm in length are exposed, as also reported by Acosta et al. (2021). An indication of a relationship between habitat preferences and color patterns was observed. Individuals with a “Reticulated” and “Black and yellow” pattern were never found in dense seagrass beds; they were associated with mixed bottoms of corals and sand. In some places, it is possible to find several color patterns, whereas in others only one color is present or is the most abundant. This was also noted by Clark (1942), who compared coloration variation in the populations in Bermuda and Jamaica.

Remarks

The taxonomic status of Isostichopus badionotus (Selenka, 1867) is considered stable since Clark’s 1922 revision of the genus Stichopus, which included a detailed study of Stichopus badionotus (currently Isostichopus badionotus) based on museum and living specimens. Six species of Stichopus had been described from the tropical West Atlantic region ( Stichopus badionotus Selenka, 1867; S. haytiensis Semper, 1868; S. moebii Semper, 1868; S. errans Ludwig, 1875; S. diaboli Heilprin, 1888 and S. xanthomela Heilprin, 1888), and two species from West African regions ( Stichopus maculatus and S. assimilis). After a detailed study of the diagnostic characters, Clark (1922) united all eight species under S. badionotus . He concluded that “color is absolutely unreliable as a distinguishing character, and body-texture, form, and tuberculation seem to be equally hopeless. The calcareous particles too undergo growth changes which lead into difficulties”.

Our extensive sampling and revision, including mtDNA sequences of each color pattern, revealed that Clark (1922) was correct in synonymizing as S. badionotus the other five species of Stichopus that had been described at that time in the West Atlantic. However, he was not right in synonymizing the two species from the East Atlantic as S. badionotus . mtDNA sequences, coloration and ossicles distinguish I. badionotus from I. maculatus as a different species. This species includes two subspecies, the nominal I. maculatus maculatus from the East Atlantic and I. maculatus phoenius from the West Atlantic, sympatric with I. badionotus . This means that Clark (1922) was also correct in distinguishing one specimen with the entire back and sides bright carmine-red as Stichopus badionotus var. phoenius, which we here elevate to sub-specific rank and transfer to I. maculatus . The East Atlantic species, S. assimilis, proved to belong to the genus Holothuria Linnaeus, 1767 (see I. maculatus maculatus remarks). Our comparative examination of ossicle differences in the species and subspecies of Isostichopus showed that Clark (1922) was also right in describing I. macroparentheses as a distinct species based on the longest C-shaped ossicles.

Although the types of the previously accepted West Atlantic species ( S. haytiensis, S. moebii, S. errans, S. diaboli and S. xanthomela) were not available for examination, their original description, online pictures and the revision in the present paper strongly suggest they are synonymous to I. badionotus, concurring with the decision by Clark (1922, 1933, 1942). These species were not thoroughly described by the original authors, and the illustrations of their ossicles were not informative, because they are so similar to each other. Heilprin (1888) presented the most extensive discussion of these five species. He noted the presence of wart-like tubercles, number of pedicels, and color as characters that would clarify confusion between S. diaboli and S. haytiensis, and among S. xanthomela, S. moebii and S. errans . Regarding color, S. diaboli was described as black, S. haytiensis as dark chocolate-brown, blotched with yellow spots, which form five longitudinal bands in the interradii, S. xanthomela as reddish-yellow with irregular blotches of black or very dark brown, S. moebii as reddish gray, slightly lighter on the abdomen with numerous large round brown-black, sometimes confluent spots on the back, and S. errans as of similar color to S. moebii . These original descriptions of color patterns from these previously accepted species fit the color patterns of specimens examined and assigned to I. badionotus in the present paper. They do not, however, fit the color patterns of I. maculatus phoenius, because there was no mention of the white blotches and small black dots characteristic of this subspecies. Some I. maculatus phoenius are uniform red or green, again colors not reported in any of these nominal species (Figs 1K–L, 15A).

The three West Atlantic species and subspecies of Isostichopus accepted in this paper can be most easily differentiated by coloration, in addition to molecular differences. Ossicles are not the best character for distinguishing I. badionotus from I. maculatus phoenius, although they are very useful for differentiating them from I. macroparentheses . The only internal morphology character to distinguish between large specimens of I. badionotus and I. maculatus phoenius is the size and shape of the calcareous ring. The dorsal radial plates in I. badionotus are longer with two dorsal radial plates having long posterior projections (3–4 mm long) turned inwards in larger individuals (L = 160-235 mm); large specimens of I. maculatus phoenius (L = 185 mm), on the other hand, have dorsal radial plates that are shorter and thicker (Fig. 4A–B). Habitat is also useful for distinguishing I. badionotus from I. maculatus phoenius (see I. maculatus phoenius remarks).

The four color forms of I. badionotus raises the question of whether these are genetically differentiated. A slight phylogenetic structure related to the color pattern was found (“Reticulated” and “Black and yellow” vs “Chips” and “Uniform” patterns) (Fig. 3A–D). These slight variations in mtDNA, correlated with color variation of the individuals in which they occur and their habitat, suggest that there may be some form of non-random mating. However, these differences are certainly not sufficient to indicate the existence of different species. Data from more populations and other molecular markers are needed to assess these results.

Examination of dorsal papillae in four specimens (and several that were not measured) of I. badionotus, from 40 mm to 230 mm long, showed that C-shaped ossicle length and table height increases during growth (Fig. 9A–B), that spines at the crown spires are thick and strong in largest specimens, and that table disc diameter and number of holes decreases in size and in number. Ossicles become more abundant in the middle-sized specimens. Ontogenetic changes in ossicle shape and size in I. badionotus have been described by Cutress (1996). Differences between our results and those presented by Cutress were in the table height of the juveniles and the number of C-shaped ossicles in the ventral body wall. We found lower tables in juveniles than in the adults. This pattern was common in all the species and subspecies of Isostichopus for which juveniles were examined. Perhaps the very small size of Cutress’s specimens (16 mm and 25 mm) could explain these differences. Cutress found the C-shaped ossicles to be more abundant in the ventral than dorsal body wall of most of the specimens she examined, while we found the opposite pattern.

The identification of specimens of I. badionotus (“Reticulated” color pattern) as belonging to the Indo-Pacific species Stichopus herrmanni in the Caribbean Sea (Rodríguez-Forero et al. 2013: 12, fig. 5), Agudelo & Rodríguez 2015: 1022, fig. 1c) is clearly erroneous. This is supported by the morphology of the ossicles. Stichopus possesses rosettes, while Isostichopus does not (Deichmann 1958). Martínez et al. (2016: 21, fig. 4) reported rosettes (Martínez et al. 2016: 21, fig. 5a) in specimens with the “Reticulated” color pattern as I. badionotus Morphotype II; however, in reality these ossicles were rods. More details about the morphology of the rosettes can be found in Samyn et al. (2005: 105, fig. 2; 2006: 31, fig. 41) and in Purcell et al. (2012, 2023).

Biology

Perhaps because of the growing interest in commercial exploitation of Isostichopus badionotus in the Caribbean Sea, there is extensive literature on the population density, distribution, fishery, and reproductive characteristics of this species. Toral-Granda (2008a) extensively reviewed the biology, ecology, and population status of sea cucumbers in Latin America and the Caribbean, including I. badionotus . Reproductive biology information was reported from Panama, Venezuela, Brazil, Bonaire, Cuba, Yucatán (Mexico) and Colombia. The smallest size at sexual maturity has been reported from Panama (13–15 cm) (Guzmán et al. 2003) and the largest from Venezuela (30 cm) (Purcell et al. 2023); in Yucatán, Cuba and Colombia the size of first maturity has been documented at 18.5, 21.5 and 22 cm, respectively (Zetina et al. 2002; Alfonso et al. 2008; Acosta et al. 2021). The sex ratio has been reported to be 1: 1 in Cuba (Aleaga 2003 in Ortega 2015), Panama (Guzmán et al. 2003), Brazil (Pires-Nogueira et al. 2001; Lima et al. 2003) and La Guajira and Santa Marta, Colombia (Invemar 2015: Acosta et al. 2021). Guzmán et al. (2003), Foglietta et al. (2004), Zacarías-Soto et al. (2013), Invemar (2015), and Acosta et al. (2021) reported that I. badionotus reproduces throughout the year, with a peak of reproductive activity between July and November, with some differences according to the location in the Caribbean Sea. In Brazil, the reproductive season has been reported in January and February and in October and November (Pires-Nogueira et al. 2001). Zacarías-Soto et al. (2013) have established that larval development from early auricularia to pentactula occurs between 19 and 22 days after fertilization. Juveniles of 654.3 μm in length were obtained on average 25 days after fertilization at 25 ± 1°C (Zacarías-Soto et al. 2013). After three months, juveniles reach lengths of 1–2 cm; in one year they have average sizes of 8 cm (Zetina et al. 2002).

Individuals of I. badionotus move approximately 0.5 m per day (Hammond 1983). Crozier (1918) calculated that in this species in Bermuda each individual fills its intestine twice a day and that the population can ingest between 500 and 1000 tons of sediment per year. Hammond (1983), on the other hand, calculated that each individual fills its intestine three or four times during daily movements.

Vergara et al. (2016) have described the relationship of I. badionotus with the pearlfish Carapus bermudensis (Jones, 1874) in Taganga Bay, Colombia. Luna-Fontalvo et al. (2014) listed the bacterial and fungal communities associated with the skin and the gut of this species. Gut histology of I. badionotus has been described by Vergara & Rodríguez (2015), including specimens of the “Chips” (Vergara & Rodríguez 2015: 1022, fig. 1a) and “Reticulated” color patterns (Vergara & Rodríguez 2015: 1022, fig. 1c, as Stichopus hermanni). They also described the histology of individuals of I. maculatus phoenius (Vergara & Rodríguez 2015: 1022, fig. 1b, as Isostichopus sp.). These authors found a similar histology of the digestive tract between the two species, but they observed differences in the thickness of the intestinal submucosal tissue, which can be related to specific feeding habits. Albinism in I. badionotus has been recorded by Wakida-Kusunoki et al. (2016) in one specimen collected in Yucatán, Mexico.

The highest population densities of I. badionotus, ranging from 5600 to 8800 ind/ha, were reported in the southeastern region of Cuba (Alfonso et al. 2004; Alfonso 2006). Ortega (2015) reported densities ranging between 900 and 3300 ind/ha in a survey conducted from 2008 and 2013 in the north part of Isla de la Juventud, Cuba, with no significant differences between years and localities. Jesús-Navarrete et al. (2018) reported a mean density of I. badionotus of 5570 ind/ha in 2011–2012 in Sisal, Yucatán, Mexico, but other surveys in this region found much lower densities. Lopez-Rocha (2011), also for Sisal, reported 217 ind/ha and compared this value with previous densities ranging between 267 to 437 ind/ha in 2007 in Progreso, Yucatan, and between 5 to 25 ind/ha at the central and east coast of Yucatan in 2000–2001. Poot-Salazar et al. (2015) and Hernández-Flores et al. (2015) estimated a density of 720 ind/ha in fishing areas near Progreso. In the Mexican Caribbean coast (Banco Chinchorro, Quintana Roo), I. badionotus is not among the most abundant species (Fuente-Betancourt et al. 2001). In Belize, significant differences in density were found in three habitats, with 10 ind/ha on the sand and sparse seagrass beds, 50 ind/ha in seagrass and rubble, and 17.7 ind/ha in sparse seagrass near shore (Rogers 2013). Guzmán & Guevara (2002) reported a density of 117.4 ind/ha in Bocas del Toro (Panama). Invemar (2015) has reported the highest mass density of I. badionotus in two regions of the Colombian Caribbean coast, 12 640 kg /km² (126.4 kg /ha) in La Guajira and 11 ind/km² (0.11 ind/ha) in Magdalena; the species, however, is scarce in other regions (Cordoba and Bolivar). In Venezuela, Tagliafico et al. (2011) reported that I. badionotus was most abundant on the East coast of Cubagua Island. At this location, it is found over Thalassia testudinum beds or mollusk shell aggregations, with an average density of 117 ind/ha.

Conservation status

Isostichopus badionotus is recognized as one of the most highly exploited and commercially valuable species in the Caribbean region, along with Holothuria (Halodeima) mexicana Ludwig, 1875 and Isostichopus maculatus phoenius (Purcell et al. 2023, as Isostichopus sp. ‘ phoenius ’). The prices of dried I. badionotus in Guangzhou and Hong Kong, China SAR retail markets ranged from US $ 203 to 402 kg-1 (Purcell et al. 2012, 2023). Currently, I. badionotus is listed as a species of Least Concern by the IUCN Red List of Threatened Species (Toral-Granda et al. 2013). However, this category could change in the future, considering, among other reasons, that the distribution of the species is now restricted to the West Atlantic. The incessant growth of Asian market demands has led the opening of new fisheries and the depletion of some populations. Furthermore, preoccupation about the conservation of this species is justified because of the differences in population densities in different areas. López-Rocha (2011) suggested that differences in density may be due to different sampling methods applied to the patchy distribution of sea cucumbers. Differences in densities of populations require differences in their management. Hernández-Flores et al. (2018) proposed a technique of improving stock assessment by considering the distribution pattern of I. badionotus .

Purcell et al. (2012, 2023) included Cuba, Nicaragua, and Venezuela as the countries where I. badionotus is fished commercially; they also reported on the illegal, unregulated, and non-quantified fishery in Colombia and Florida (USA), Puerto Rico, and the United States Virgin Islands, where the species is of potential commercial interest. Currently, in addition to those countries, reported commercial fisheries include Mexico and Belize (Rogers 2013; Rogers et al. 2017; Jesús-Navarrete et al. 2018). Characteristics and current state of the fishery in each country are different. In Yucatán, Mexico, where perhaps one of the better regulated sea cucumber fisheries in the Caribbean occurs, the resource has decreased (Rodríguez-Gil et al. 2015). In Belize, H. mexicana and I. badionotus have been legally fished since 2009 (Perez & Garcia 2012 in McNab & Rogers 2017). In Cuba, the most recent fishery analysis in Isla de la Juventud, a well studied fishery since 2004 (Alfonso et al. 2008; Ortega & Alfonso 2011; Ortega 2015), showed that the population of I. badionotus is healthy, and its fishery remains stable (Ortega 2015). In Colombia, illegal and unregulated fishery of I. badionotus has been reported and quantification is being developed (Borrero-Pérez et al. 2006; Reyes-Sánchez et al. 2011; Invemar 2013, 2015; Rodríguez-Forero et al. 2013). Currently, I. badionotus is included in the Red Book of Marine Invertebrates of Colombia (Borrero-Pérez et al. 2022); data from La Guajira fishery showed a 32% reduction in catches per unit of effort between 2006–2017, despite some cessations of the fishery during these years (Reyes-Sánchez et al. 2011; Borrero-Pérez et al. 2022). In Panamá, the fishing of sea cucumbers is banned by Executive Decrees (157-2003, 217-2009), but an illegal fishery occurs in areas such as Bocas del Toro (Vergara-Chen et al. 2015). In Florida, there has been, since 2014, a regulation about a vessel limit of 200 sea cucumbers per trip in state and federal waters (FWC 2014). Nicaragua fishery is the subject of the most alarming report, because it involves not only the overexploitation of I. badionotus and H. mexicana, including immature sea cucumbers as an increasing proportion of the catches, but also human injustice, abuse and even death (Rogers et al. 2017). This fishery also involves Honduras, from where its operating financiers (Chinese and Koreans) originate.

Rogers et al. (2017) highlight another reality of the sea cucumber fishery, which is the price at which artisanal fishers in the Caribbean having been selling their catches. In Nicaragua, this price is only US $ 6.00 kg-1 (Rogers et al. 2017) and in Colombia it is less than US $ 0.29–1.89 kg-1 (Invemar 2013), prices that are far from the US $ 22 kg-1 value reported by Purcell et al. (2012, 2023) and those in Hong Kong China SAR retail markets.

Aquaculture is a strategy for species conservation. In the most complete review about sea cucumber aquaculture (Lovatelli et al. 2004), I. badionotus is not mentioned, possibly because interest in this species as a resource for aquaculture started only after 2004. Currently, there is some research on this subject (Zacarías-Soto et al. 2013), but most studies are still in progress (Pelegrín-Morales et al. 2009; Sarkis 2015; Felaco & Olvera-Novoa 2017; Rogers 2018). Martínez et al. (2016) present a manual for the cultivation and processing of sea cucumbers including specimens of the “Chips” (as I. badionotus Morfotipo I) and “Reticulated” color patterns (as I. badionotus Morfotipo II). In Panama, the use, exclusively for mariculture, of I. badionotus and H. mexicana, is permitted (Executive Decree 20-2019) and farming projects are being established. In Colombia, sea cucumbers are not considered a fishing resource, so fishing and aquaculture are not allowed (Puentes et al. 2014; Invemar 2015; Borrero-Pérez et al. 2022).