Ophioderma, Muller & Troschel, 1840

Humara-Gil, Karla J., Granja-Fernández, Rebeca, Bautista-Guerrero, Eric, Solís-Marín, Francisco A. & Rodríguez-Troncoso, Alma P., 2024, Delimitation of Ophioderma teres (Lyman, 1860) and Ophioderma unicolor H. L. Clark, 1940 stat. nov. (Echinodermata: Ophiuroidea), including the description of two new species, European Journal of Taxonomy 947, pp. 130-174 : 166-167

Key to the eastern Pacific species of Ophioderma

This key serves as a reference for the identification of valid nominal species of Ophioderma in the EP. Before use, the following should be considered: 1) possible new undescribed species have been reported in the region, particularly in California, Baja California (Pacific side), and Clipperton Island ( Lessios & Hendler 2022). Caution should be used when employing this key to identify specimens from these locations; 2) some diagnostic characters vary according to size (e.g., granulation extent, fragmentation of DAPs, number of arm spines) ( Granja-Fernández et al. 2020; Stöhr et al. 2020; Humara-Gil et al. 2022). Therefore, small individuals (= younger) may not have developed all the characters included in the key.

1. Disc covered with flattened, brick-like granules ...................................... O. vansyoci Hendler, 1996

– Disc covered with rounded granules ................................................................................................. 2

2. Dorsal arm plates mostly or always entire ........................................................................................ 3

– Dorsal arm plates fragmented into two or more pieces .................................................................... 6

3. Dorsal arm plates mostly entire; a few can be divided into up to two pieces. Radial shields naked. Adoral shields covered with granules. Arms with transverse bands (in vivo and preserved) ............ ................................................................................................................ O. panamense Lütken, 1859

– Dorsal arm plates entire. Radial shields covered with granules. Adoral shields naked .................... 4

4. Distal genital slit with granule-bearing scales only. Disc olive green with dark pink or red (in vivo), or light brown (preserved); arms with olive green and dark pink/red (in vivo) or dark brown transverse bands (preserved) ................................................................................... O. variegatum Lütken, 1856

– Distal genital slit with naked and granule-bearing scales. Disc brown (preserved); arms with transverse bands (in vivo and preserved) .......................................................................................... 5

5. Disc dark brown with small white spots. Up to 11 arm spines ........................................................... .......................................................................................... O. hendleri Granja-Fernández et al., 2020

– Disc orange (in vivo) or brown (preserved), with dark blotches. Up to six arm spines ..................... ..................................................................................................... O. pentacanthum H.L. Clark, 1917

6. Coloration uniform brown on disc and arms .................................................................................... 7

– Coloration with characteristic patterns on disc or arms .................................................................... 8

7. Distal genital slit with granule-bearing scales only .................................................. O. bichi sp. nov.

– Distal genital slit with naked and granule-bearing scales ..... O. unicolor H.L. Clark, 1940 stat. nov.

8. Disc dark olive green to brown (in vivo), or dark gray to brown (preserved); arms with transverse bands (more subtle in preserved specimens) and parallel white bands in the median and distal arm sections .................................................................................... O. occultum Humara-Gil et al., 2022

– Disc with specks or rings; arms without bands ................................................................................ 9

9. Disc dark brown with darker, sinuous rings on both dorsal and ventral sides. Radial shields naked ..................................................................................................................................... O. aija sp. nov.

– Disc speckled. Radial shields covered or naked ............................................................................. 10

10. Granules present on the disc and the distal part of dorsal arm plates in the proximalmost and median arm sections .................................................................... O. peruanum Pineda-Enríquez et al., 2013

– Granules limited to the disc and arm base ..................................................... O. teres ( Lyman, 1860)