Eucalyptocrinites tumidus, Ausich & Wilson & Vinn, 2012
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publication ID |
https://doi.org/ 10.4202/app.2010.0094 |
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persistent identifier |
https://treatment.plazi.org/id/BF03720D-FFCE-FFF2-BC7D-FCCA20FCFB86 |
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treatment provided by |
Felipe |
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scientific name |
Eucalyptocrinites tumidus |
| status |
sp. nov. |
Eucalyptocrinites tumidus sp. nov.
Fig. 3A View Fig .
Etymology: From Latin tumidus , swollen; refers to the convex, swollen appearance of the calyx plates.
Holotype: GIT 405−243 View Materials .
Type locality: Kaugatuma Cliff, Saaremaa Island, Estonia.
Type horizon: Middle Äigu Beds, Kaugatuma Formation, Pridoli, Late Silurian.
Material.— Holotype only.
Diagnosis.— Eucalyptocrinites with low, bowl−shaped calyx. Very convex calyx plates. Basal plates not visible in lateral view, completely hidden beneath the proximal columnal. Partition plates expand distally but only modestly; central groove along distal partition plates absent; flat−topped tegmen; anal tube absent. Distal arms do not extend above distal tegmen.
Description.—The calyx is relatively small for the genus and has a low bowl shape ( Fig. 3A View Fig 1 View Fig ). The base of calyx is truncate with basal plates in a small basal concavity and hidden by the proximal column. The calyx plate sculpturing is nodose to very nodose, and sutures are broadly impressed ( Fig. 3A View Fig 2). The basal circlet is hidden. The radial circlet is complete and approximately 12% of calyx height. The 5 radial plates are pentagonal and approximately 2.8 times wider than high. Normal interrays are in contact with the tegmen partition plates. The first interradial plate is decagonal, higher than wide, and much larger than the radial plates or first primibrachials. The second range has two adjacent plates sutured to the interradial tegmen partition plates. Each interradial plate of the second range is approximately 2.3 times higher than wide. The posterior interray is indistinguishable from normal interrays ( Fig. 3A View Fig 2). The first primibrachials are tetragonal, approximately 1.5 times wider than high, and smaller than radial plates and primaxils. The second secundibrachial is axillary in all rays, yielding four arms per ray. One fixed intrabrachial occurs distally with the partition plate above The fixed intraradial is approximately 1.5 times higher than wide.
The tegmen is composed of ten partition plates that extend to the top of the tegmen. The tegmen is higher than the full height of the arms ( Fig. 3A View Fig 1 View Fig ). Partition plates expand in width distally to less than twice the proximal width. The tegmen is flat topped ( Fig. 3A 3 View Fig ) and formed primarily of partition plates, but the center of the distal tegmen is composed of two irregular circlets of five plates each. The anal opening is flush with the tegmen surface, and the anal tube is absent.
The 20 free arms are atomous, pinnulate; and approximately the first five tertibrachials are uniserial cuneate with remainder of the brachials biserial. Arms taper distally and do not extend beyond the flat top of the distal tegmen.
Proximal column circular, holomeric, heteromorphic, other details not known.
Discussion.—Because other Baltic species of Eucalyptocrinites have smooth or ridged calyx plate sculpturing, the very convex calyx plate sculpturing of E. tumidus is unique.
Measurements.—GIT 405−243: crown height, 28.1 (to top of tegmen); maximum crown width, 23.5; calyx height, 6.2; calyx width at distal−most calyx, 20.2; radial plate height, 1.8; radial plate width, 4.1.
Geographic and stratigraphic range.—Middle Äigu Beds, Kaugatuma Formation (Pridoli) at Kaugatuma Cliff, Saaremaa Island, Estonia.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.