Isostichopus macroparentheses
Creators: name: Borrero-Pérez, Giomar H.
name: Solís-Marín, Francisco A.
name: Lessios, Harilaos
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Echinodermata
Holothuroidea
Synallactida
Stichopodidae
Isostichopus
Isostichopus macroparentheses

description: Isostichopus macroparentheses (Clark, 1922)
Figs 1 P’–Q’, 3A–D, 4E, 5B, 9, 10E, 11E, 22–24; Tables 1–3
Stichopus macroparentheses Clark, 1922: 61–63, pl. 1 figs 1–7.
Stichopus megaparentheses – Clark 1922: 63. Typographic error.
Stichopus macroparentheses – Deichmann 1926: 21; 1930: 82–83, pl. 5 figs 37–43. — Clark 1933: 110 (as S. macraparentheses, typographic error).
Isostichopus badionotus – Deichmann 1957: 4–5; 1963: 106. — Miller & Pawson 1984: 54. — Cutress 1996: 105, 112. — Pawson et al. 2010: 34–35.
Stichopus macroparenthesis – Deichmann 1957: 4–5. Typographic error.
Isostichopus macroparentheses – Pawson 1976: 374, fig. 1d. — Solís-Marín et al. 1998: 524. — Hendler & Pawson 2000: 282. — Laguarda-Figueras et al. 2001: 28, fig. 11a–d; 2005: 119. — Alvarado & Solís-Marín 2013: 650.
Original name
Stichopus macroparentheses Clark, 1922.
Current status
Isostichopus macroparentheses (Clark, 1922).
Name-bearing type
Holotype MCZ HOL-921, MCZ HOL-225 (ossicle slide of the holotype); paratype MCZ HOL-1214.
Type locality
Montego Bay, Jamaica.
Diagnosis
C-shaped ossicles> 90 µm long on average; disc tables in dorsal papillae and body wall completely reduced in adults (Figs 10E, 23A); tridimensional spheres and straight/spiky rods in the respiratory tree (Fig. 23F); semi-translucent and smooth body wall; color not variable, background of dorsal side light yellow-brown, with irregularly arranged blurred large and small darker brown spots (Figs 22A, C, 24); mtDNA divergence from other species of the genus>16.2% in COI-Fr1 (barcoding region),> 16.3% in COI-Fr2 and>9.5% in 16S (Table 2).
Material examined
Holotype
JAMAICA • L = 50 mm, contracted; Montego Bay, Bogue Island; 18.46908° N, 77.931086° W; Mar. 1912; H.L. Clark leg.; MCZ HOL-921 • ossicle slide of the holotype; same data as for holotype; MCZ HOL-225.
Paratype
USA • 1 spec. (L = 65 mm); Florida, Tortugas, Bird Key; 24.6185° N, 82.8854° W; Jun. 1917; Carnegie Institute, Tortugas Laboratory leg.; MCZ HOL-1214.
Other material
GULF OF MEXICO – Mexico • 1 spec.; Veracruz, Isla Lobos; 21.465° N, 97.22866° W; depth 2–7 m; 16 Mar. 2011; F. Solís-Marín leg.; coral, rocky bottom; ICML-UNAM 5.88.1 • 1 spec.; Veracruz, Isla Lobos; 21.4726667° N, 97.23116° W; depth 12 m; 17 Mar. 2011; F. Solís-Marín leg.; coral, rocky bottom; ICML-UNAM 5.88.2 • 1 spec.; Veracruz, Isla Lobos; 21.4541667° N, 97.22500° W; depth 1.5 m; 13 Mar. 1976; coral, rocky bottom; ICML-UNAM 5.88.3.
CARIBBEAN SEA – Mexico • 1 spec.; Quintana Roo, Puerto Morelos, off Rodman shipyard; 20.87472° N, 86.85083° W; depth 2 m; 1 Jul. 1995; F. Solís-Marín leg.; rocky bottom; ICML-UNAM 5.88.0 • 1 spec.; Quintana Roo, Akumal Bay; 20.39375° N, 87.31426° W; depth 2.5 m; 25 May 2012; F. Solís-Marín leg.; rocky bottom; ICML-UNAM 11053. – US Virgin Islands • 1 spec. (L = 60 mm); St. Croix Island, Rod Bay; 17.733761° N, 64.614086° W; depth 0.5 m; 17 Jul. 1990; R. Aronson leg.; USNM E40833. – British Virgin Islands • 1 spec. (L = 135 mm); Guana Island; 18.472111° N, 64.576794° W; depth 2 m; 1 Jun. 1997; A. Kerr leg.; USNM E47524. – Antigua and Barbuda • 1 spec. (L = 80 mm); Antigua Island, English Harbor; 17° N, 61.7667° W; 7 Jan. 1918; C. Nutting leg.; USNM E4391 • 1 spec. (L = 70 mm); same data as for preceding; USNM E22322 • 1 spec. (L = 50 mm); same data as for preceding; USNM 1283366. – Curaçao • 1 spec.; Carmabi Marine Research Station; 12.12177° N, 68.96964° W; depth 3 m; 18 Feb. 2020; G. Paulay leg.; reef shelf; BCUR-0532; UF20352. – Belize • 1 spec. (L = 20 mm); Tobacco Cay; 16.945997° N, 88.060744° W; depth 2 m; 10 Jun. 2016; L. Geyer and G. Borrero-Pérez leg.; rocky bottom, ImrBe99; USNM 1659484 • 1 spec. (L = 40 mm); Carrie Bow Cay; 16.803074° N, 88.081939° W; depth 2 m; 12 Jun. 2016; A. Hiller and G. Borrero-Pérez leg.; rocky bottom, ImrBe107; USNM 1659485 • 1 spec. (L = 30 mm); Belize, Carrie Bow Cay; 16.80295° N, 88.08145° W; depth 1–2 m; Apr. 1975; M. Carpenter leg.; USNM E18627 • 1 spec. (L = 25 mm); Carrie Bow Cay, near transect along wall of trough behind fore reef crest; 16.80295° N, 88.08145° W; depth 18 m; 22 Mar. 1979; G. Hendler leg.; USNM 1021529.
Description
EXTERNAL APPEARANCE. Small to medium size species, preserved specimens up to 135 mm long (n = 11, range 20–135 mm, holotype: 50 mm, paratype: 65 mm). Body loaf-like, length/width ratio 3.1± 0.5 (n = 11, range 2.4–4.1, holotype 3.8, paratype 4.1). Holotype (contracted) and paratype rounded posteriorly and anteriorly (Fig. 22A, C), similar to living specimens, which are convex/subcylindrical in cross section (Fig. 24). Body wall soft and not very thick (paratype: 0.5–1 mm; USNM E47524 (L = 135 mm): 2–4 mm). Anus supra-terminal, circular and not surrounded by large papillae. Mouth directed ventrally, encircled by a collar of medium sized papillae (paratype: 2 mm high; holotype: retracted). Nineteen large peltate tentacles in the holotype (retracted) and paratype (3–4 mm long, 2.5–3 mm wide shield, with 0.5 mm deep indentations); 20 tentacles in the largest specimen USNM E47524 (6–7 mm long; 4–4.5 mm wide shield). Large live and preserved specimens with flat and inconspicuous dorsal and lateral papillae (Fig. 24F, J–K) (USNM47524: less than 1 mm high and 2 to 5 mm wide at the base). Juvenile live specimens with medium to large dorsal papillae, rounded or pointed, ending in a thin tip, scattered irregularly; lateral papillae similar in shape to the dorsal ones, but smaller and less obvious (Fig.24A–E). Papillae in the holotype and paratype small (Fig. 22A, C). Lateral rows not sharply defining the dorsal and ventral surface in either juveniles or adults, in living or preserved specimens (Figs 22, 24). Ventral surface in both juveniles and large specimens densely covered with cylindrical pedicels, arranged in three longitudinal rows (Figs 22, 24); most of the pedicels retracted and longitudinal rows not evident in the largest preserved specimen (USNM E47524).
COLOR AND BODY WALL APPEARANCE. Body wall surface smooth and semi-translucent (Figs 1, 22, 24) (see also Clark 1922: 62). Color not variable, living specimens light yellow-brown in the background on the dorsal side with irregularly arranged blurred big and small darker brown spots that do not coincide with the papillae; papillae lighter, with the distal end almost white, or at least lighter than the base of the papillae, yellow according to Clark (1922) (Fig. 1 P’–Q’). Ventral surface lighter than dorsal with small spots in the same dorsal pattern, pedicels translucent white, end plate of darker brown (Fig. 24). Preserved specimens similar to live ones in color, tentacles with light brown tubes and darker shields (Fig. 24F–I). Holotype and paratype uniform whitish on the dorsal and ventral surfaces, with slightly darker tentacles (Fig. 22A, C). Living juveniles (20 mm long) similar in color as adults, tentacles translucent white (Fig. 24A–E).
INTERNAL ANATOMY (based on MCZ HOL-1214 (paratype, L = 65 mm), USNM E47524 (L = 135 mm) and MCZ HOL-921 (holotype, L = 50 mm, mostly deteriorated)). Calcareous ring diameter 7 mm in the 65 mm specimen and 11 mm in the largest 135 mm one; radial elements almost as long as wide (L = 65 mm: 2 mm wide, 1.5 mm long; L = 135 mm: 5 mm wide, 4.2 mm long), with four anterior small lobes and small posterior projections that are larger in the largest specimen (1.2 mm) (Fig. 4E); interradial elements pointed anteriorly and concave in the posterior margin, about half as wide as radial elements and somewhat shorter (L = 65 mm: 2.5 mm wide, 1.5 mm long; L = 135 mm: 2.5 mm wide, 3 mm long). Single and irregularly helical stone canal (L = 65 mm: 4 mm long; L = 135 mm: 10 mm long), attached to the mesentery, ending in a flat leaf-like madreporite, 2 mm wide in the largest specimen. Tentacle ampullae in the largest specimen 12–16 mm long, 2–3 mm long in the 65 mm specimen, and 1.5–2 mm in the holotype. One tube-like Polian vesicle in the 65 mm specimen and the holotype (both 6 mm long, 1 mm wide); two tube-like Polian vesicles in the largest specimen, one longer (15 mm long, 2.5 mm wide) than the other (9 mm long, 1.5 mm wide), streaked longitudinally, with spots and dark tips. Gonads found only in the holotype (Fig. 11E). Longitudinal muscles approximately 1.5 and 2.5 mm wide in the 65 mm specimen and the holotype, and 4 mm wide in the largest specimen (USNM E47524), divided and attached to the body wall medially and laterally. Respiratory trees insert to the cloaca arising from a common stem 13 mm long in the 135 mm specimen, the left tree extending with the intestine (L = 65 mm: 25 mm long; L = 135 mm: 65 mm long) and right tree free (19 mm and 45 mm long, respectively).
OSSICLES (based on MCZ HOL-921 (holotype, L = 50 mm), MCZ HOL-225 (holotype permanent slide), MCZ HOL-1214 (paratype, L = 65 mm), USNM E47524 (L = 135 mm, SEM images (Fig. 22)); USNM 1659484 (juvenile, L = 20 mm) and USNM 1659485 (juvenile, L = 40 mm); juveniles only for dorsal papillae and body wall). Ossicles of the holotype are mostly deteriorated; however, some aspects of the remaining ossicles, the permanent slide MCZ HOL-225, and the description of Clark (1922), who only described the ossicles from papillae and pedicels, are included.
Dorsal papillae with tables, thin C-shaped rods, perforated plates, and large, curved rods (Figs 10E, 22B, 23A). All types of ossicles present in all specimens, from 20 mm to 135 mm long. Numerous C-shaped rods, a few S-shaped ones, ranging from 91 to 155 (x = 133) µm long; 2–3 times as long as tables are high, usually abundant in the papilla tip, sometimes in the base; no obvious correlation with body length (Figs 9A, 10E). Numerous tables with notable changes in shape and size during growth. Tables in 20, 40 and 65 mm specimens 31 to 48 (x = 40) µm high and with large discs with smooth and wide margins 24–77 (x = 48) µm across the disc, characterized by one large central perforation, which appears as four large and symmetrical holes, without outer holes, or usually with 4 outer smaller holes alternating with the central holes (Fig. 10E, also see Clark 1922: pl 1 fig. 2; Deichmann 1930: pl 5 fig. 39); some tables with 5 to 15 (rarely 20) holes in the disc, forming a complete outer ring, rarely with one more incomplete ring. Spires composed of four pillars usually narrowed at the tip, although also with parallel pillars, crossbeam closer to the base; crown of spire rounded without teeth or with few teeth; minute teeth on tables with larger discs. These tables with large discs disappear in individuals during growth, and are replaced with regular Isostichopus tables with smaller discs, ranging from 32 to 42 (x = 39) µm across the disc in the 65 mm specimen, with one rounded central perforation and 2–9 peripheral holes, always arranged in one simple ring. Similar tables scarce in the largest specimen (L = 135 mm), most of the tables with disc completely reduced, 17–27 (x = 23) µm across and spires composed of four parallel pillars slightly or strongly constricted, 29–38 (x = 34) μm high; one crossbeam near the base, pillars ending in triplets of small spines forming an expanded crown (Figs 10E, 23A). Few perforated plates, located in the papilla tip, with few large perforations, larger in the center of the plate, ranging from 82 to 127 µm across; Clark (1922) used the term “end plates” to describe these dorsal perforated plates. Slightly or strongly curved rods, usually with quadrangular projections in the central area, sometimes perforated, 41 to 289 µm long, increasing gradually in size during growth.
Dorsal body wall with tables and rare C-shaped and S-shaped rods (Figs 10E, 23A). Numerous smaller tables similar to those from the papillae, 33–50 µm (x = 40 µm) high and 23–103 µm (x = 45 µm) across disc in specimens less than 65 mm long (Fig. 10E); no tables with disc in the 135 mm specimen, disc usually completely reduced 14–19 (x = 17) µm across disc and 31–37 (x = 34) µm high (Fig. 10E).
Pedicels with tables, C-shaped rods, perforated plates, large and curved rods, and end plates (Fig. 23B). Numerous tables with one large central perforation, which appears as four symmetrical holes, with 4 to 12 outer smaller holes usually in a single ring, both in the 65 mm and 135 mm long specimens; no tables with reduced disc; tables 27–40 (x = 35) μm high and 30–55 (x = 42) µm across the disc in the 65 mm long specimen, and 22–32 (x = 27) μm high and 20–44 (x = 32) µm across the disc in the 135 mm specimen; numerous C-shaped ossicles, but not in all pedicels; C-shaped ossicles from the ventral surface much narrower, smaller than those from the dorsal side, as also mentioned by Clark (1922), 78 to 112 (x = 99) µm long in the 135 mm specimen, shorter than 165 µm reported by Clark in the type specimens. Numerous elongated perforated plates, with many perforations larger and elongated in the center of the plate 145–212 µm long in the 65 mm specimen and 228–284 µm long in the 135 mm specimen. Slightly curved rods with wide perforated expansions in the middle, 173–243 µm long in the 65 mm specimen and 268-323 µm long in the 135 mm specimen; end plate 489–569 µm across.
Ventral body wall with numerous tables similar to those from pedicels; C-shaped ossicles not present.
Tentacles with tables and rods (Fig. 23C). Few tables having smooth discs with four large central and symmetrical holes with 1 to 3 peripheral holes in the 65 mm specimen (31–41 μm across disc) and 0 to 12, mostly 4 in the 135 mm specimen (38–51 μm across disc). Spire low, composed of four incomplete pillars that usually are not joined at the top; without crossbeams connecting adjacent pillars. Numerous strongly or slightly curved spiny rods of different sizes ranging from 64 to 839 µm, increasing gradually with body size.
Mouth membrane with tables, C-shaped rods and simple rods (Fig. 11E); tables larger than those from dorsal and ventral sides, having spinous discs with one large central perforation, which appears as four symmetrical holes usually with 4 to 7 peripheral holes, not forming a complete ring in the 65 mm specimen (46–82 µm high, 62–101 µm across the disc) and with one or two rings of 4 to 14 perforations in the first and 2 to 8 perforations in the second ring in the 135 mm specimen (50–97 µm high, 43– 108 µm across the disc); spires low, with four incomplete pillars not joined at the top, or composed of a variable number of pillars that are joined in a slender reticulate spire, cross beams not distinguishable; numerous C-shaped ossicles 37–71 µm long in the 65 mm specimen and 33–89 µm long in the 135 mm specimen; numerous small rods 54–108 µm long in the 65 mm specimen and 35–71 µm long in the 135 mm specimen.
Longitudinal muscles with small rods 33–63 µm long; few tables 35–38 µm high and 29–38 µm across the disc in the 135 mm specimen (Fig. 23D). Posterior cloaca with numerous C-shaped ossicles 54–93 µm long in the 65 mm specimen and 61–89 µm long in the 135 mm specimen (Fig. 23E). Anterior cloaca in the 135 mm specimen with spinous simple or bifurcated rods 78–112 µm long; large tridimensional spheres 141–195 µm across and tables similar to those of the dorsal papillae and body wall 25–30 µm high and 15–32 µm across the disc (Fig. 11E); muscle ossicles not found in the 65 mm specimen. Respiratory trees with strongly spinous straight or cross-shaped rods 178–283 µm long in the 65 and the 135 mm long specimens; large tridimensional spheres 157–250 µm across in the 135 mm long specimen (Fig. 23F); one table with a reduced disc (30 µm high, 18 µm across disc) in the 65 mm specimen. Intestine with spinose or smooth deposits in a cross shape, sometimes with bifurcated ends 51–71 µm long in the holotype, 31–43 µm in the paratype and 53-114 µm in the 135 mm long specimen (Fig. 23G). Gonads with delicate and large rods 102–233 µm long in the holotype (Fig. 11E); gonads not found in the paratype or in the 135 mm specimen.
Distribution
Thus far, I. microparentheses is only known from the Gulf of Mexico and the Caribbean Sea, in few disjunct localities shown in Fig. 5B, including Bird Key, Florida Keys; Veracruz and Quintana Roo, Mexico; Carrie Bow Cay and Tobacco Cay, Belize; English Harbor, Antigua Island; Guana island, British Virgin Islands; St. Croix, US Virgin Islands; Bogue Island, Jamaica and Curaçao. The record from Sarasota, West Florida is from a juvenile (15 mm total length), which was not confirmed as I. macroparentheses (USNM E10473). We only collected this species in Belize. Bathymetric distribution 0.5 to 18 m. The unconfirmed juvenile USNM E10473 was collected at 48 m depth.
Habitat
Unlike the other species and subspecies of the genus, I. macroparentheses is not common or abundant, and most of the collected specimens are juveniles. There is little information about the habitat of the species. According to the collection data and literature references, juveniles and adults of this species live under or among rocks in the back reef, reef crest, and fore reef (Clark 1922, 1933; Deichmann 1930; Pawson 1976). According to Deichmann (1930) and Clark (1933) some specimens collected in Antigua were found on sand among eel-grass.
Remarks
Clark (1922) described this species from two juvenile specimens (holotype L = 50 mm, contracted; paratype L = 65 mm). The species was also reviewed by Deichmann (1930), who amended its diagnostic characters. However, due to changes during growth and the natural variability of ossicles, doubts about its validity as a separate species arose. Deichmann (1957) considered S. macroparentheses a synonym of S. badionotus, proposing that specimens with large C-shaped ossicles were juveniles of S. badionotus. Pawson (1976), however, argued that the difference between the C-shaped ossicles between the species is “dramatic, particularly when one compares juveniles of I. macroparentheses with I. badionotus ”. However, Miller & Pawson (1984), Cutress (1996) and Pawson et al. (2010), accepted the species as a synonym of I. badionotus. Laguarda-Figueras et al. (2005) and Alvarado & Solís-Marín (2013) have considered I. macroparentheses as a valid species in taxonomic lists. Prior to the present study there has been no detailed review setting the differences of I. macroparentheses from I. badionotus. Furthermore, adult specimens of I. macroparentheses had not been examined, so the characteristics of the species were based only on the two small specimens designated as types by Clark (1922). We conclude that I. macroparentheses is the species of Isostichopus that is best differentiated from the others. It exhibits several diagnostic characteristics, among which those related to the ossicles stand out, i.e. the size of the C-shaped ossicles, the disc tables in dorsal papillae and body wall, and the three-dimensional spheres and straight/spiky rods in the respiratory tree.
Cutress (1996) found that one adult specimen of I. badionotus (196 mm long) had few C-shaped ossicles longer than 100 µm in the dorsal median body wall. She concluded that the large size of C-shaped ossicles described in I. macroparentheses fell within the range of variation of I. badionotus, accepting I. macroparentheses as a synonym of I. badionotus. However, the average size of C-shaped ossicles in the dorsal side of this I. badionotus specimen was 74 µm (range 52 to 124 µm) and 71 µm (48 to 90 µm) in the ventral side; while these ossicles in dorsal papillae of I. macroparentheses are 91–142 µm (x = 113 µm) long, and in pedicels 78 to 112 µm (x = 99 µm) long, clearly larger than that of the other Isostichopus (Fig. 9A).
Examination of dorsal papillae in four 20–135 mm long specimens (and several that were not measured) of I. macroparetheses, showed that this species displays pronounced changes during growth in table height, disc diameter and number of holes in table discs The disc of the tables from dorsal papillae presented in Fig. 10E (USNM 1669484, MCZ HOL-1214), and drawn by Clark (1922: pl. 1 figs 1–2) and described as diagnostic by Deichmann (1957), can be useful to distinguish juveniles or specimens of intermediate sizes (holotype and paratype) from other species. These structures, however, can be scarce in some individuals, and disc of tables with more holes can be more abundant. In larger specimens (L = 135 mm), the table discs are completely reduced. Ossicles are less abundant in the largest specimens than in middle sized specimens. C-shaped ossicle size does not change during growth.
Biology
There is no information available on population status and ecology.
Conservation status
Currently Isostichopus macroparentheses is included in the IUCN Red List of Threatened Species in the category of “Data Deficient”. “There is little to no information available on the population status, habitat, ecology, major threats, or conservation measures occurring to this species” (Samyn 2013).
description: Published as part of Borrero-Pérez, Giomar H., Solís-Marín, Francisco A. & Lessios, Harilaos, 2024, Understanding the color variability and resolving taxonomic confusion in the sea cucumber Isostichopus badionotus (Echinodermata, Holothuroidea): a revision of the genus Isostichopus, pp. 1-96 in European Journal of Taxonomy 949 (1) on pages 72-81, DOI: 10.5852/ejt.2024.949.2641, http://zenodo.org/record/13710645