WoRMS taxon details
Perometrinae AH Clark, 1909
Genus Erythrometra AH Clark, 1908
Genus Helenametra AM Clark, 1966
Genus Hypalometra AH Clark, 1908
Genus Nanometra AH Clark, 1907
Genus Perometra AH Clark, 1907
Genus Helenametra AM Clark, 1966
Genus Hypalometra AH Clark, 1908
Genus Nanometra AH Clark, 1907
Genus Perometra AH Clark, 1907
marine, brackish, fresh, terrestrial
Clark, A. H. (1909). New genera and higher groups of unstalked crinoids. <em>Proceedings of the Biological Society of Washington.</em> 22:173-178. [details]
Messing, C.; Gondim, A.I.; Taylor, K. (2023). World List of Crinoidea. Perometrinae AH Clark, 1909. Accessed through: World Register of Marine Species at: https://marinespecies.org/aphia.php?p=taxdetails&id=710753 on 2023-09-25
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original description
Clark, A. H. (1909). New genera and higher groups of unstalked crinoids. <em>Proceedings of the Biological Society of Washington.</em> 22:173-178. [details]
From editor or global species database
Diagnosis Antedonidae with centrodorsal rounded conical; aboral polerounded, commonly rugose or tuberculate; cirrus-free portion broad or small. Cirrus sockets crowded, alternating in irregular circles, increasing in size toward base. Adoral side of centrodorsal smooth, without radial pits, interradial furrows, or ridges. Centrodorsal cavity 30-40% of centrodorsal diameter. Cirri rather long, with 25-55 cirrals; distal cirrals with aboral spine or process. Radials usually prominent, with exposed surface concave and projecting, to low and almost concealed midradially. Radial articular facet gently sloping, rather wide, separated by narrow interradial margin. Interarticular ligament fossae triangular, approximately as high as adoral muscle fossae. Ridge separating interarticular from muscle fossa narrow, commonly indistinct. Midradial ridge and notch usually low and wide. Radial cavity funnel shaped. Arms divided at primibrachial 2 and at secundibrachial 2 in some arms of Perometra afra. Primibrachial 1 low, commonly narrow and laterally overhung by proximal end of primibrachial 2. Synarthry between brachials 1-2 usually embayed. First pinnule stout, with <20 pinnulars. First interior and sometimes first exterior pinnule frequently absent. Second pinnule differs from genital pinnules. [details]
