Ophioderma panamense Lütken, 1859

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 : 24-27

Ophioderma panamense Lütken, 1859

Figs 5 E–J, 6; Table 1

Ophioderma panamensis Lütken, 1859: 193 .

Ophiocryptus granulosus Nielsen, 1932: 334–335 , fig. 38.

Ophiura panamensis – Lyman 1865: 32–34. — Verrill 1867: 253–254. — Ives 1889b: 175.

Ophioderma panamensis – Ives 1889a: 76–77. — Koehler 1907: 282. — McClendon 1909: 35, fig. 1. — H.L. Clark 1913: 205; 1915: 300–301. — Campbell 1921: 2, fig. 1. — Caso 1951: 265–272, figs 25–28; 1962: 296, 302; 1979: 210, pl. 97–100; 1986: 225, 239, pl. 14–19. — Granja-Fernández et al. 2014: 132–134 , fig. 6a–f; 2015a: 41; 2015b: 95; 2017: 172, 174.

Ophioderma panamense – H.L. Clark 1915: 301–302; 1917: 443; 1940: 341–342. — Nielsen 1932: 327–330. — Ziesenhenne 1937: 227, 1955: 192–197. — Boolotian & Leighton 1966: 10, fig. 23. — Luke 1982: 33. — Solís-Marín et al. 2005: 128; 2013: 570. — Honey-Escandón et al. 2008: 63. — Alvarado et al. 2010: 48.

Ophiocryptus granulosus – Honey-Escandón et al. 2008: 63. — Cortés 2012:173. — Granja-Fernández & López-Pérez 2012: 363. — Bastida-Zavala et al. 2013: 367. — Solís-Marín et al. 2013: 569.

Diagnosis

Radial shields naked, oval, small, and widely separated. Adoral shields covered by granules. Up to 12 arm spines, short and with a blunt tip. In vivo coloration: disc green, brown or grey mottled with red, orange or yellow; arms with transverse bands, lighter and darker.

Material examined

Holotype

PANAMA • 1 spec.; Panama; NHMD-107679 .

Other material

See: Supplementary material.

Holotype redescription

DD = 21.9 mm; 5 arms, AL = 91.9 mm. Disc flat and pentagonal. Dorsal disc densely covered by rounded and small granules, granule density 61 mm-2; rubbed off in some areas. Radial shields naked, small, oval, and separated ( Fig. 5E ). Ventral interradii covered with granules similar to those on dorsal side of disc ( Fig. 5F ). Four genital slits on each interradius; proximal genital slits rounded and shorter than distal slits, in contact with distal part of oral shield and with 1 st LAP; distal genital slits elongated and surrounded by granules and numerous and imbricated scales next to lateral arm plates ( Fig. 5F ).

Oral shields slightly broader than long, rounded triangular, with convex obtuse proximal angle, straight distal edge, obtuse lateral angles. Madreporite with a small, circular, and shallow depression located in distal part and larger than other oral shields. Adoral shields covered by granules, which are larger than those on rest of body. Jaws bear 7–8 papillae at each side: LyOs small, 1.5× as long as broad, angled upwards; AdShSp largest, rounded; 2°AdShSp a little larger and similar in shape to LOPa; LOPa 3–4 conical and pointed, separated; IPa similar and separated from LOPa; TPa 1–2 at jaw tips, robust and pointed, larger and more robust than LOPa, widely separated. vT similar in shape but slightly larger than TPa. OPRSp 1, large and pointed at each side, visible within buccal cavity. Granules covering oral plates, larger than those on dorsal disc and interradii ( Fig. 5G ).

Dorsal base of arms covered by granules and with approximately 15 scales laterally at dorsal arm plates. Dorsal arm plates 3× broader than long, overlapping and with an irregular to straight proximal and distal margin, with rounded lateral edges; a few dorsal arm plates can be fragmented in 2 pieces ( Fig. 5H ). First ventral arm plate small, broader than long; with a small indentation distally ( Fig. 5G ). Subsequent ventral arm plates quadrangular, slightly broader than long; distal edge slightly concave ( Fig. 5I ). Paired and rounded pores between 1 st and 2 nd, and 2 nd and 3 rd ventral arm plates ( Fig. 5 F–G). LAP with up to 8–9 arm spines. Arm spines with blunt tip and robust; length approximately ½ of size of LAP. Dorsalmost arm spine shortest and narrowest; ventralmost arm spine longest and slightly more robust, in contact with tentacle scale of succeeding joint ( Fig. 5I ). Two tentacle scales; adradial tentacle scale ovoid, elongated, approximately half length of ventral arm plate; abradial tentacle scale slightly shorter, subtriangular ( Fig. 5I ).

Color pattern beige in ethanol, likely faded ( Fig. 5J ).

Disarticulated ossicles

Specimen analyzed: 1 spec., ICML-UNAM 3.18.60 (DD = 11.1 mm, AL = 44.4 mm). Radial shield (external view) irregularly rounded, with an indented proximal margin, an incised abradial edge with a projection, an indented distal edge, and convex adradial margin, it is bordered by 7 pores on median to proximal margin (which are covered/overlapped by disc scales and granules in intact animal) ( Fig. 6A ). Only exposed surface is domed center portion of radial shield. Outer surface of stereom is an open mesh of pores and knobs ( Fig. 6A ). Dorsal arm plate somewhat rectangular, 3× as wide as long; proximal margin convex to straight, and distal margin straight, 7 spurs on proximal portion of external surface ( Fig. 6B ). Ventral arm plate as long as wide, quadrangular with proximal side truncated and with a pointed-shape spur, lateral sides concave forming border of a small tentacle pore, and distally indented ( Fig. 6C ). LAP D-shaped, 3× as high as wide, with 8 spine articulations sunken in notches of distal edge ( Fig. 6 D–E). Ventral portion of LAP projecting ventro-proximalwards and ventro-distal tip projecting ventralwards ( Fig. 6D ). Proximal edge of LAP with 2 prominent and elongated spurs, which are protruding and modify central-proximal edge ( Fig. 6D ); between spurs and across remaining proximal margin a discernible band of different stereom structure is present ( Fig. 6D ). Outer surface finely meshed with relatively large rounded stereom knobs ( Fig. 6G ). Inner surface of LAP with a continuous ridge on proximal edge, and on ventro-distal margin with 2 spurs matching those on external surface ( Fig. 6F ), and 4 pores in center. Spine articulations ventralwards increasing in size ( Fig. 6E ). Lobes with a weak sigmoidal fold, tilted, and curved ( Fig. 6H ). Ventral lobe smaller than dorsal lobe ( Fig. 6H ). Proximal vertebrae ( Fig. 6I ) almost oval, as wide as long, with large aboral muscle flange and smaller oral muscle flange. Distal face of vertebrae with large muscle flanges, with typical zygospondylous articulation ( Fig. 6J ). Tentacle scale longer than wide, with a scale-like surface ( Fig. 6K ). Spines with a scale-like surface, a blunt tip, and laterally flattened ( Fig. 6L ). Dental plate consists of several pieces, 1 st piece bears 2 TPa and a single wide tooth, while rest of pieces with a single tooth socket per piece (4 in total), none of sockets penetrate plate ( Fig. 6M ).

Habitat and distribution

USA (California), Mexico (Baja California, Gulf of California, Nayarit, Jalisco, Colima, Michoacán, Guerrero, Oaxaca, Marías Islands, Marietas Islands, Revillagigedo Islands), El Salvador, Nicaragua, Costa Rica (Caño Island, Cocos Island, Murciélagos Islands), Panama, Colombia, Ecuador (Galapagos Islands), and Peru ( Solís-Marín et al. 2013; Granja-Fernández et al. 2014). From intertidal to 20 m depth ( Solís-Marín et al. 2013). Found under rocks and in rubble, coral, sand, algae, and tide pools ( Maluf 1988; Granja-Fernández et al. 2014).

Remarks

Lütken (1859) did not designate any specific type material in his description of O. panamense , but according to the International Code of Zoological Nomenclature ( ICZN 1999), Article 73.1.2, the only specimen reported in the original description (NHMD-107679) must be treated as holotype by monotypy. The description provided by Lütken (1859) is mostly based on the comparison of this species with other Ophioderma from the Atlantic; therefore, a redescription of the holotype is provided in the present work.

We observed that the holotype, as well as adult voucher specimens, can have some 'fragmented' or 'broken' dorsal arm plates ( Fig. 5H ) indicating that they might have been crushed by moving between rocks and these disruptions are the result of injury ( Ziesenhenne 1955; Stöhr et al. 2020b). Hendler (2018) observed that 'fragmented' dorsal arm plates in O. panamense frequently occur on basal arm segments of adult specimens, but are rare on distal arm segments of adults and juveniles. It is important to emphasize that these fragmentations on the dorsal arm plates are a result of mechanical damage and are not an inherent feature of the species as occurs in O. peruanum , O. teres or O. vansyoci .

Along with O. hendleri sp. nov., O. panamense is one of the most conspicuous and abundant ophiuroids in the Eastern Pacific, but it has often been confused with O. teres and O. variegatum (see Discussion section). Due to its commonness, O. panamense is one of the most studied and commented species of the Eastern Pacific ( Lyman 1865; Verrill 1867; Ives 1889a; McClendon 1909; Nielsen 1932; Ziesenhenne 1955; Granja-Fernández et al. 2014), but many of these studies may be based on misidentified specimens.

Figures

Fig. 5. A–D. Ophioderma hendleri sp. nov. A–B. In vivo coloration in natural habitat. C–D. In vivo coloration of collected specimens. – E–J. Ophioderma panamense Lütken, 1859, holotype (NHMD- 107679, DD = 21.9 mm). E. Dorsal disc. F. Ventral disc. G. Mouth. H. Dorsal arm. I. Ventral arm. J. Dorsal view.

Fig. 6. SEM images of skeletal elements of Ophioderma panamense (ICML-UNAM 3.18.60, DD = 11.1 mm). A. Radial shield (external view), the pores marked with arrows. B. Dorsal arm plate, with seven spurs. C. Ventral arm plate with one spur. D. Lateral arm plate, external face, with two spurs. 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, proximal face. J. Arm vertebra, distal face. K. Tentacle scale. L. Arm spine. M. Dental plate fragments.