Henricia

Xiao, Ning, Liao, Yulin & Liu, Ruiyu, 2011, Records of the genus Henricia Gray, 1840 (Echinodermata: Asteroidea: Echinasteridae) from Chinese waters, Zootaxa 3115, pp. 1-20 : 18

Key to the species of Henricia from Chinese waters

1. Usually three furrow spines in a distinct vertical series............................................... H. arcystata

- Furrow spines single or double........................................................................... 2

2. Abactinal skeleton generally forming a wide meshwork ( Fig. 4 E, 9E, 10E), with large papular areas; abactinal spinelets usually scattered along the ridges surrounding papular areas, not in definite clusters; marginal plates discernible, but not conspicuous, especially in superomarginals............................................................................ 3

- Abactinal skeleton generally forming a compact meshwork ( Fig. 6 E, 8E, 11E), with only small papular areas; multiple abactinal spinelets in groups; marginal and ventrolateral plates forming three very regular, conspicuous series adjacent to adambulacral plates.......................................................................................... 5

3. Intermarginal and ventrolateral areas relatively narrow; arms long (R/r>5.5) and slender; subadambulacral spines 10 to 15............................................................................................... H. pacifica

- Intermarginal and ventrolateral areas more wide; arms short (R/r<4) or moderate long (4<R/r<5.5); subadambulacral spines less than 10.......................................................................................... 4

4. Arms short, swollen, constricted at base; 3 to 8 small and sharp abactinal spinelets generally arranged in comb-shape along the ridge surrounding papular areas............................................................ H. aspera robusta

- Arms moderate in length, gradually tapering; 4 to 15 small abactinal spinelets generally in single or double curved series surrounding papular areas......................................................................... H. ohsimai

5. Intermarginal areas usually confined to small triangular spaces at arm base........................................ 6

- Intermarginal areas not confined to small triangular spaces at arm base, usually extending for half arm length or more..... 7

6. Abactinal spinelets numbering about 20 to 35 for a plate, very short, not fine or delicate, showing a granuliform appearance; subadambulacral spines 7 to 17, not numerous............................................. H. leviuscula leviuscula

- Abactinal spinelets very numerous (about 40 to 70 for a plate), fine and delicate, looking like the surface covered with fluff; subadambulacral spines 25 to 40, numerous.............................................. H. leviuscula spiculifera

7. Abactinal plates ( Fig. 11 E) subquadrate in form and uniform in size, regularly arranged in oblique transverse row..................................................................................................... H. regularis

- Abactinal plates ( Fig. 5 E, 6E) not subquadrate in form and varying in size, arranged irregularly, not arranged in discernable linear series.......................................................................................... 8

8. 5 to 13 fine abactinal spinelets in groups, not numerous; subadambulacral spines slender, 13 to 15; furrow spines double.................................................................................................. H. exigua

- Numerous abactinal spinelets densely crowded, about 30 or more for a plate; subadambulacral spines bluntly pointed, 15 to 22; furrow spines single, rarely double in the distal half of arm........................................... H. densispina

Figures

FIGURE 4. Henricia aspera robusta Djakonov. A, abactinal view. Note short and swollen arms; B, actinal view; C, abactinal ray. Note spinelets arranged in comb-shape; D, actinal ray; E, cleared disc and madreporite showing wide meshwork with large papular area; F, cleared actinal ray.

FIGURE 5. Henricia densispina (Sladen). A, abactinal view; B, actinal view; C, abactinal ray; D, actinal ray; E, cleared abactinal ray showing abactinal plates arranged irregularly; F, cleared actinal ray.

FIGURE 6. Henricia exigua Hayashi. A, abactinal view; B, actinal view; C, abactinal ray. Note a few abactinal spinelets; D, actinal ray. Note two furrow spines; E, cleared abactinal ray showing abactinal plates arranged irregularly; F, cleared actinal ray.

FIGURE 11. Henricia regularis Hayashi. A, abactinal view; B, actinal view; C, abactinal ray; D, actinal ray; E, cleared abactinal ray showing abactinal plates arranged regularly and small recessed popular areas; F, cleared actinal ray.