Hemieuryalidae Verrill, 1899

Stöhr, Sabine, Hugall, Andrew F., Thuy, Ben & Martynov, Alexander, 2018, Morphological diagnoses of higher taxa in Ophiuroidea (Echinodermata) in support of a new classification, European Journal of Taxonomy 416, pp. 1-35 : 18

Family Hemieuryalidae Verrill, 1899

Type genus

Hemieuryale von Martens, 1867 (type species: H. pustulata von Martens, 1867 ).

Other genera

Actinozonella Stöhr, 2011 , Astrogymnotes H.L. Clark, 1914 , Ophioholcus H.L. Clark, 1915a , Ophioplus Verrill, 1899a , Ophiozonella Matsumoto, 1915 , Ophiozonoida H.L. Clark, 1915a , Quironia A.H. Clark, 1934 , Sigsbeia Lyman, 1878b , Ophioplocus Lyman, 1861 .

Diagnosis

Dorsal disc with scales and plates or thickened skin, neither granules nor spines, but in some genera with tubercles. Strongly tuberculous stereom in all arm plates. No accessory arm plates. Arm spine articulation with single small opening (e.g., Hemieuryale ) or separate muscle and nerve openings (e.g., Ophiozonella , Ophioplocus ); articulations placed at an angle to each other. Tooth sockets shallow with indistinct borders in Hemieuryale but in Ophiozonella only ventral sockets like this, dorsal ones as large fenestrations with septum.

Remarks

Heteromorphic assemblage of genera with numerous reductions and specializations. The arm spine articulation with only two parallel ridges may be such a reduction, as the type species of Ophiozonella ( O. longispina (H.L. Clark, 1908)) has the dorsal and ventral lobes proximally separated by a strong, irregularly denticulate ridge (or vertical series of merged knobs).