Echinasteridae

Clark, Roger N. & Jewett, Stephen C., 2010, A new genus and thirteen new species of sea stars (Asteroidea: Echinasteridae) from the Aleutian Island Archipelago, Zootaxa 2571, pp. 1-36 : 33-34

Key to the family Echinasteridae in the shallow (<20 m) waters of the Aleutian Islands.

1a Marginal plates obvious and arranged in distinct linear series ..................................................................................... 2

1b Marginal plates absent or rudimentary ............................................................................................... Aleutihenricia (3)

2a Paired oral plates united at apices by a single much enlarged spine or tooth ................................... Odontohenricia (5)

2b Paired oral plates not united at apices by an enlarged spine or tooth .......................................................... Henricia (8)

3a Abactinal plates bearing 2–4 (rarely 5) spines; adambulacrals with 7–13 spines; color in life solid white................... ..................................................................................................................................................................... A. derjugini

3b Abactinal plates typically with 5 or more spines; number of adambulacral spines variable;color in life not white .... 4

4a Abactinal plates bearing 5–9 spines; adambulacrals with 7 or 8 coarse spines; color in life usually nearly solid red- dish on abactinal suface ............................................................................................................................ A. beringiana

4b Abactinal plates bearing 8–15 spines; adambulacrals with 9–13 spines; color in life mottled with yellow-orange and maroon .............................................................................................................................................................. A. federi

5a Apical oral tooth very stout, robust, often hyaline; much larger than marginal teeth .................................................. 6

5b Apical oral tooth rather long and slender, adjacent sub-apical teeth about 3/4 as long, marginal teeth shorter.......... 7

6a Abactinal skeleton rather coarse, plates forming an irregular, open reticulum; R rarely exeeding 8.5 cm ..... O. fisheri

6b Abactinal skeleton compact, plates small, closely spaced; R frequently exceeding 12 cm ....................... O. ahearnae

7a Abactinal surface very smooth appearing; covered by thick dermal layer; rays very long and slender; oral plates with 13–16 marginal and sub-oral spines .............................................................................................................. O. violacea

7b Abactinal surface not smooth appearing or covered with thick dermal layer; rays long and, slender; oral plates with 16–31 marginal and sub-oral spines ............................................................................................................. O. aurantia

8a Superomarginal plates inconspicuous; inferomarginals about 3times as large as superomarginals; adambulacrals with 8–15 spines, 1+2–4+6–11, first 3–5 considerably longer than others ........................................ H. sanguinolenta

8b Marginal and actinal inter-radial series of plates conspicuous ..................................................................................... 9

9a Abactinal skeleton very open, papular areas as large or larger than plates or plate ridges ........................................ 10

9b Abactinal skeleton tight, papular areas smaller than plates or plate ridges ................................................................ 16

10a Abactinal plates bearing groups of 16–27 very slender spinelets with 1–3 apical thorns; adambulacrals with 10–16 slender spines in 3 rows ................................................................................................................................. H. elachys

10b Abactinal plates forming spinose ridges..................................................................................................................... 11

11a Abactinal spines very long (1.25–2 mm), slender, sharply pointed; arranged in tufts of 1–5; abambulacral plates with single (often staggered) row of 4–8 slender, sharply pointed or spatulate spines ..................................... H. longispina

11b Abactinal spines less than 1 mm in length, not arranged in tufts ............................................................................... 12

12a Abactinal skeleton composed of narrow ridges, bearing a single row of spines ........................................................ 13

12b Abactinal skeleton composed of broad ridges, bearing 2 or more rows of spines ..................................................... 14

13a Abactinal ridges bearing 4–7 relatively long, thick, sharp spines, encased in thick membrane; adambulacrals with single row of 3–5 grading, stout, blunt spines ......................................................................................... H. asthenactis

13b Abactinal ridges bearing 3–6 short, thick, well spaced thorns; adambulacrals with a single staggered row of 4–6, webbed spines ................................................................................................................................................. H. aspera

14a Abactinal ridges bearing 5–11 short, thick, bunt spines, in 2 irregular rows; adambulacrals with 9–11 spines, 3 longest nearest furrow ...................................................................................................................................... H. echinata

14b Abactinal ridges bearing 15 or more spines in 2–5 rows............................................................................................ 15

15a Abactinal ridges with 15–20 short thick thorns in a group or 2–4 irregular rows; adambulacrals with 4–6 (rarely to 8) spines in a single staggered row ..................................................................................................................... H. oculata

15b Abactinal ridges with 25–30+ short, thick, thorns in a group, or in 3–5 irregular rows; adambulacrals with 8–10 thick, blunt spines in 2 staggered rows ........................................................................................................ H. rhytisma

16a Abactinal surface rough, plates often forming irregular vermiculiform ridges; superomarginals larger, and of higher relief than abactinals, and curving notably upwards, at base of rays; adambulacrals with 12–15 spines, 1+2+ 9-12 in group or 3 rows .............................................................................................................................................. H. iodinea

16b Abactinal surface not rough; superomarginals not prominent and of higher relief than abactinal plates .................. 17

17a Adambulacral plates with fewer than 12 spines ......................................................................................................... 18

17b Adambulactral plates with more than 12 spines ......................................................................................................... 19

18a Adambulacral plates with 4–9 short, thick often distally swollen spines, arranged in a single, or sometimes a staggered double row; prominent row of large singular papulae between actinal inter-radial and inferomarginal plate series; R rarely exceeding 4 cm, R:r 2–5; color in life, highly variable ......................................................... H. tumida

18b Adambulacral plates with 7–10 cylindrical, spines arranged 1+ 2 rows of 3–5; R often exceeding 7 cm, R:r 5.8–8; color in life, red or orange-red .................................................................................................................... H. vermilion

19a Disc broad, rays short, broad at base, tapering to slender tips, R:3–3.4; abactinal plates with 11–32 spinules; adambulacral plates bearing 15–19 spines, 1 + 2 + 2 + 10-14 in 3 rows ................................................................ H. gemma

19b Disc small, rays long, slender; R:r 4.5–7 .................................................................................................................... 20

20a Adambulacral plates with 30–45+ spines ................................................................................................................... 21

20b Adambulacrals with fewer than 25 spines .................................................................................................................. 22

21a Abactinal and actinal surfaces velvet-like in appearance, abactinal plates with 50–90+ very fine, divergent spinules; intermarginals lacking ............................................................................................................................... H. multispina

21b Abactinal plates small, with fewer than 45 spinules; two rows of intermarginals, extending up to 60 % of R ............. ....................................................................................................................................................................... H. insignis

22a Abactinal plates round, with 9–35 spinules bearing 3–8+ thorns; abactinal surface with 3 rows of close-set plates, lacking papular areas between, forming distinct lines; adambulacrals with 14–17 spines, 1+ 1–2 + 11–14 in 3 rows. ........................................................................................................................................................................ H. lineata

22b Abactinal plates round on disc, triangular on rays, with 37–60 spinules bearing 3 thorns; adambulacrals plates with 19–24 spines 1–2+2–3+ 16–20 in group or 3 rows ........................................................................................ H. uluudax