Goniasteridae Forbes 1841

GONIASTERIDAE Forbes, 1841 Diagnosis Modified from Mah (2023). Body shape pentagonal to strongly stellate (R/r=1.0 to 4.0), body variably soft to stout, thickness ranging from strongly arched to relatively flat, interradial arcs variably angular to straight. Surface covering ranges from bare and smooth to thick dermis embedded with granulation. Abactinal surface with widely variable range of plate morphologies ranging from discrete polygonal abutted plates, to shaft-like tabulae or paxillae to imbricate or irregularly arranged plates embedded in thick dermis. Plate surface ranges from smooth and bare to a highly variable range of primary ornamentation, such as large spines as well as smaller accessory structures, primarily granules, but also including spinelets, surficial plates and pedicellariae. Pedicellariae present or absent, ranging from bivalve, paddle-like, forceps-shaped and etc. When large pedicellariae present, these tend to be more consistent in location. Marginal plates, generally blocky, but variably forming well-defined periphery with either lateral or abactinal-facing in two distinct series, superomarginals and inferomarginals, present from terminal to interradius. Marginal plates with variable accessories, such as granules, spineless, or pedicellariae. Some groups with large primary structures such as spines. Marginal plate surface variably covered by dermis or bare. Several genera with abutted superomarginals over midline on arm, variably along whole length or near armtip. Actinal plates, abutted, quadrate to polygonal or irregular in shape in chevron-like formation with full series adjacent to the adambulacral plate series becoming more irregular distally adjacent to the contact with the inferomarginal plate series. Actinal plate surface with variable cover of granules, spinelets or pedicellariae. Primary structures such as spines or large pedicellariae present in some taxa. Adambulacral plates with furrow spines, variably narrow to thick, with blunt or pointed tips. Further spination on adambulacrals variably granular to more spine or spinelet like.