Ophioderma variegatum Lütken, 1856

Granja-Fernández, Rebeca, Pineda-Enríquez, Tania, Solís-Marín, Francisco Alonso & Laguarda-Figueras, Alfredo, 2020, Ophioderma hendleri sp. nov. (Echinodermata: Ophiuroidea: Ophiodermatidae) and its congeners from the Eastern Pacific, European Journal of Taxonomy 729, pp. 11-41 : 31-35

Ophioderma variegatum Lütken, 1856

Figs 8–9 ; Table 1

Ophioderma variegata Lütken, 1856: 21 .

Ophioderma variegata – Lütken 1859: 199. — Lütken & Mortensen 1899: 100–101, pl. 1, figs 1–3. — Koehler 1907: 282; 1914: 7. — H.L. Clark 1913: 205. — Ziesenhenne 1955: 198. — Luke 1982: 33. — Granja-Fernández et al. 2015a: 41; 2015b: 95.

Ophiura variegata – Verrill 1867: 254. — Lyman 1875: 3; 1882: 10.

Ophioderma variegatum – H.L. Clark 1915: 302, pl. 18, figs. 7–8; 1940: 343. — Nielsen 1932: 330– 332, fig. 36. — Boone 1933: 114–115, pl. 67. — Ziesenhenne 1937: 227. — Maluf 1988: 84, 203. — Solís-Marín et al. 2005: 128; 2013: 570. — Honey-Escandón et al. 2008: 63. — Alvarado et al. 2010: 48.

Diagnosis

Radial shields covered by granules. Base of the arms and distal genital slits with granulation. First ventral arm plate large, broader than long. Oral shields oval, larger than broad, proximal margin rounded with an obtuse angle, distal edge convex, lateral margins straight. Naked adoral shields, longer than broad. Up to 9 arm spines, very large and slender; dorsalmost and ventralmost a little bit shorter than the rest. In vivo coloration: dorsal disc olive-green with dark pink or red; arms with transverse olive-green and dark pink-red bands.

Examined material

Lectotype (here designated)

NICARAGUA • 1 spec.; Realejo ; 9.1 m (5 fathoms); NHMD-107680 .

Paralectotypes (here designated)

NICARAGUA • 2 specs; same collection data as for lectotype; NHMD-619214 .

Designation of lectotype and paralectotype

In the original description of Ophioderma variegatum, Lütken (1856) only mentioned the existence of one uncatalogued specimen (DD = 14 mm) as part of the type material. However, three specimens are present in this lot (pers. com. Schiøtte, 2019) all of similar size (DD = ~ 12.5 mm). The similarities of the morphological characters and sizes make it impossible to determine which of them corresponds to the specimen described by Lütken (1856). There are some discrepancies between the measurements from Lütken (1856) and our measurements which could be due to the preservation of the specimens through time. Because of this, and according to Recommendation 73F of the International Code of Zoological Nomenclature ( ICZN 1999), we propose the designation of the specimen NHMD-107680 as the lectotype and NHMD-619214 contains the paralectotypes (two specimens) for O. variegatum .

Other material

See: Supplementary material.

Description (Lectotype)

DD = 12.4 mm; 5 arms, AL = 62 mm. Disc flat and rounded. Dorsal disc densely covered by rounded and very small granules, granule density 222 mm-2; granules extend to base of arms. Some granules rubbed off in some areas of disc. Radial shields covered by granules (rubbed off in some parts due to preservation) ( Fig. 8A ). Interradii covered with granules, similar to those on dorsal disc ( Fig. 8B ). Four genital slits on each interradius; proximal genital slits elongated and shorter than distal slits, in

contact with distal part of oral shield and with first LAP; distal genital slits elongated and surrounded by granulation ( Fig. 8B ).

Oral shields longer than broad, oval, proximal margin convex obtuse angled, distal edge convex, lateral margins straight. Madreporite with a small, circular and shallow depression located in center of oral shield. Adoral shields naked, triangular, longer than broad, separated. Jaws bear 8–9 papillae on each side: LyOs very small, as long as broad, angled upwards; AdShSp largest, rounded; 2°AdShSp smaller but similar in shape to AdShSp; LOPa 4–5 conical, pointed and separated, 1 st LOPa similar in shape to and smaller than 2°AdShSp; IPa sometimes large, elongated, pointed and separated; TPa 2 at jaw tips, larger than LOPa, elongated, robust and pointed, separated. Granules covering oral plates slightly longer than those on dorsal disc and interradii ( Fig. 8C ).

Dorsal base of arms with granules. Dorsal arm plates, 2× broader than long, trapezoidal, overlapping ( Fig. 8D ). First ventral arm plate large, broader than long, oval ( Fig. 8C ). Subsequent ventral arm plates quadrangular, slightly broader than long; distal edge slightly concave ( Fig. 8E ). Paired, rounded, and very small holes between 1 st and 2 nd, and 2 nd and 3 rd ventral arm plates ( Fig. 8 B–C). LAP with up to 7–8 arm spines.Arm spines with a blunt tip, slender, and very large. All arm spines of almost same size except dorsalmost and ventralmost, which are just a little shortest than rest ( Fig. 8E ); length approximately ¾ of size of LAP. Tentacle scales 2; adradial tentacle scale ovoid, elongated; abradial tentacle scale slightly shorter, subtriangular ( Fig. 8E ).

Specimen (ethanol preservation) discolored but with a disc with different shades of brown and arms with transverse dark brown bands ( Fig. 8F ).

Disarticulated ossicles

Specimen analyzed: 1 spec., ICML-UNAM 3.20.4 (DD = 13.6 mm, AL = 66.5 mm). Radial shield (external view) irregularly rounded, with an incised proximal margin, a slightly indented abradial edge with a tiny projection, a convex distal edge, and convex adradial margin, bordered by 9 pores along median to proximal margin (which are covered/overlapped by disc scales and granules in intact animal) ( Fig. 9A ). Dorsal arm plate arched and somewhat trapezoid-shaped, 2 × as wide as long; proximal edge convex with 5 spurs on proximal portion of external surface, distally straight and incised ( Fig. 9B ). Ventral arm plate 2× as wide as long, rectangular-shaped with proximal side truncated and with a pointed-shape spur, lateral sides concave forming border of tentacle pore, distal margin convex ( Fig. 9C ). LAP D-shaped, 2× as high as wide, with 9 spine articulations sunken in notches of distal edge ( Fig. 9 D–E). Ventral portion of LAP projecting ventro-proximalwards ( Fig. 9D ). Proximal edge of LAP with 2 prominent and elongated spurs, which are protruding and modify central-proximal edge ( Fig. 9D ), between spurs and across remaining proximal margin a discernible band of different stereom structure is present ( Fig. 9D ). Outer surface finely meshed with rounded stereom knobs ( Fig. 9G ). Inner surface of LAP with a continuous prominent ridge on proximal edge (see arched view) and on ventrodistal margin 2 spurs matching those on external surface, with 1 perforation on vertical furrow ( Fig. 9F ). Spine articulations ventralwards increasing in size ( Fig. 9E ). Lobes with a weak sigmoidal fold, tilted, and curved ( Fig. 9H ). Ventral lobe less conspicuous than dorsal lobe ( Fig. 9H ). Proximal vertebrae with a wing-like muscle flange ( Fig. 9J ). Distal face of vertebrae almost round, as wide as long, with large and irregular (sinuous) aboral muscle flange, with typical zygospondylous articulation ( Fig. 9I ). Spines with a scale-like surface, a blunt tip and laterally flattened ( Fig. 9K ). Dental plate consists of several pieces, 1 st piece has 2 TPa and 1 wide tooth, while rest of pieces with 1 tooth socket per piece (5 in total), none of sockets penetrate plate ( Fig. 9L ). Oral plate as long as high, adradial plate with a less indented middle section, and 4 oral papillae sockets ( Fig. 9M ).

Habitat and distribution

USA (California), Mexico (Baja California, Gulf of California, Jalisco, Oaxaca, Isabel Island, Revillagigedo Islands, Marías Islands), Nicaragua, Costa Rica (Cocos Island), Panama (Pearl Islands) and Galapagos Islands. From intertidal zone to 110 m depth. Collected in sand, rock, rubble, coral, algae, shell, oysters, and mangrove leaves ( Ziesenhenne 1937; Clark 1940; Maluf 1988; Solís-Marín et al. 2013; Granja-Fernández et al. 2015a).

Remarks

In the original description of O. variegatum, Lütken (1856) provided just a brief description, but later he extended it ( Lütken, 1859). However, the description provided in the present work is the most complete to date. All the characters mentioned by Lütken (1856, 1859) correspond with the lectotype and paralectotype designated in this work. Although the type specimens are discolored, many authors ( Lütken 1859; Verrill 1867; Lütken & Mortensen 1899; H.L. Clark 1913, 1940; Koehler 1914; Boone 1933) and our present work coincide that the coloration of this species consists of an olive-green disc with irregular blotches of bright rose-red and the arms banded with lighter and darker grayish green, brown or white every two to five dorsal segments.

Although O. variegatum and O. panamense are completely different in overall morphology ( Table 1 ), during our revisions we observed that it is very common to find specimens of O. variegatum identified as O. panamense , and vice versa. This tendency is very common in some published works (see references below); for example, we detected that in the description (i.e., naked radial shields and covered adoral shields) as well as the images of the species by Caso (1951, 1962, 1979, 1986), the specimens identified as O. variegatum were misidentified and corresponded to O. panamense . All the specimens studied by Caso are deposited at ICML-UNAM, and this identity was corroborated (see: Supplementary material). It is very feasible that the material mentioned in Caso et al. (1996) also corresponds to O. panamense , but neither a description nor images of the studied specimens are provided in this work and therefore we cannot confirm it.

The jaw of the type material of O. variegatum was closed, but like the other species of Ophioderma , voucher specimens with open jaws have one large and pointed OPRSp on each side, visible within the buccal cavity. It is important to recall that OPRSp were previously mentioned as spiniform structures or as a conspicuous pointed papilla (e.g., H.L. Clark 1917). Hendler (2018) coined the term suggesting that OPRSp in Ophioderma (along with OPa and teeth) are used to grip food between the closed jaws and to retain items in the buccal cavity, facilitating a feeding habit of predation and scavenging.

According to our study, O. variegatum is less abundant and less conspicuous in rock and coral reef zones of the Eastern Pacific compared to O. panamense . Ophioderma variegatum tends to inhabit deeper areas (up to 110 m) and it is commonly collected by dredging, whereas O. panamense is easily collected by hand in shallow waters (up to 20 m depth).

Maluf & Brusca (2005) reported O. variegatum for Gorgona Island ( Colombia) but without any supporting data; therefore, we suspect that this record is invalid. Nevertheless, due to the wide geographic distribution of the species, it is very plausible to find it in Colombia (or even further south), but specimens are needed to confirm this record.

Figures

Fig. 8. Ophioderma variegatum Lütken, 1856, lectotype (NHMD-107680, DD = 12.4 mm). A. Dorsal disc. B. Ventral disc. C. Mouth. D. Dorsal arm. E. Ventral arm. F. Dorsal view.

Fig. 9. SEM images of skeletal elements of Ophioderma variegatum (ICML-UNAM 3.20.4, DD = 13.6 mm). A. Radial shield (external view), deepest pores marked with arrows. B. Dorsal arm plate, with five spurs. C. Ventral arm plate, with one spur. D. Lateral arm plate, external face, with two spurs and one condyle. E. Lateral arm plate, lateral face, with spine articulations. F. Lateral arm plate, internal face. G. Outer surface of the LAP (D) with fine mesh and rounded knobs. H. Spine articulations with a weak sigmoidal fold and tilted lobes. I. Arm vertebra, distal face. J. Arm vertebra, proximal face. K. Arm spine. L. Dental plate fragments. M. Oral plate, adradial face, with arrows pointing to four oral papillae sockets.