694


Journal of Paleontology 92(4):681–712


study USNM 639907–USNM 639914, OSU 54482–OSU 54489, and CMC IP76355–CMC IP76361.


Measurements.—See Supplemental Table 4.


Remarks.—Variable characters include calyx shape in lateral profile, grouping or non-grouping of arms in each ray, nature of primibrachials, plating of interrays, shape of tegmen, and nature


recognized from the Fort Payne Formation, but E. magnificus and E. ramulosus have wider geographic distributions, as noted below.


of tegmen plates. In lateral profile, the base of the calyx may be flat, slightly convex, or quite convex. Arms within a ray may be grouped, in which case the maximum calyx width has a penta- gonal basal view outline; or arm openings are not grouped, yielding a subcircular outline at the maximum calyx width. As discussed by Van Sant (1964, p. 110, 111), the first primibra- chial may be present as a typical tetragonal brachial plate, pre- sent but some shape so as not to occupy the entire distal suture of the radial plate, or the typical first primibrachial is completely absent so that the first primibrachial is axillary. This variability exists within rays of a single individual or among individuals. Contrary to discussions in Lane (1958) and Van Sant


(1964), specimens of Alloprosallocrinus conicus from the Lake Cumberland area may have interrays in contact with the tegmen. In specimens with distinct calyx plate sutures, ~10% of regular interrays have a very long first interradial that is in contact with the tegmen. The CD interray is clearly displayed in three individuals from the Fort Payne Formation, and in every case the middle plate in the second range is elongate and in contact with the tegmen. The tegmen shape may be either conical or have interradial depressions extending vertically along the tegmen. Finally, the plates of the tegmen vary from smooth to nodose. Themorphological variation recognized in Alloprosallocrinus


conicus is relatively broad for a Paleozoic crinoid. Newly discovered specimens expand further this disparity with recogni- tion that rarely the regular interrays and/or CD interray are/is in contact with the tegmen in some specimens. However, there are no co-varying sets of characters suggestive of different species, and the variation is regarded as intraspecific, as suggested by Lane (1958) and Van Sant (1964). In 1897, Wachsmuth and Springer questionably reassigned


Alloprosallocrinus depressus Casseday and Lyon, 1862 to Agaricocrinus. This specimen has never been illustrated, but the cotypes (USNMS 1062) are available and are considered herein a junior synonym of Alloprosallocrinus conicus.


Genus Eretmocrinus Lyon and Casseday, 1859


Type species.—Eretmocrinus magnificus Lyon and Casseday, 1859, by monotypy.


Other species.—Early Viséan species of Eretmocrinus are E. remibrachiatus expansus Wachsmuth and Springer, 1897; E. granuliferous Wachsmuth and Springer, 1897; E. magnificus, E. ramulosus, and E. spinosus (see Ausich and Kammer, 2010 for full list of species assigned to Eretmocrinus). Eretmocrinus cassedayanus is known only from the Edwardsville Formation, Indian Creek, Indiana, and E. remibrachiatus expansus is only known from the Montrose Chert Member of the Keokuk Limestone in Illinois and Iowa. Eretmocrinus spinosus is only


Diagnosis.—Calyx shape low to flat cone or expanding with concave sides; basal concavity absent; calyx as high as or lower than tegmen; calyx plates smooth, nodose, spinose, stellate, with or without ray ridges; plates commonly with distinct sutures; basal plates low, truncate, or with wide to very wide lateral expansion at base; radial plates low; first primibrachial tetra- gonal; rays not lobate; regular interrays not in contact with tegmen; CD interray not in contact with tegmen; tegmen low to medium cone to medium inverted bowl, commonly asymmetric; tegmen plates smooth, convex, or nodose; anal tube cylindrical; arm facets face outward (subvertical); free arms 12–20, unbran- ched, spatulate distally (from Ausich and Kammer, 2010).


Occurrence.—Eretmocrinus is recognized from Tournaisian to the early Viséan (early to late Osagean) of North America and has a single anomalous occurrence in the Atokan of Colorado.


Remarks.—Early Viséan crinoid faunas in Indiana, Kentucky, and Tennessee are typically well represented by individuals assigned to Eretmocrinus. The Fort Payne Formation is not an exception with three species currently known from the Fort Payne: E. magnificus, E. ramulosus,and E. spinosus.In addition, hybrid specimens assigned to Eretmocrinus magnificus× Eretmocrinus spinosus are recognized (Ausich andMeyer, 1994). Species characters in Eretmocrinus include calyx width to


height ratio, calyx height to tegmen height ratio, calyx plate sculpturing, basal circlet percent of calyx height, radial circlet percent of calyx height, dimensions of radial plates, plating in regular interrays, connection or non-connection of CD interray with the tegmen, plating in the CD interray, number of secundibrachials, plate sculpturing of anal tube plates, and arm number.


Eretmocrinus magnificus Lyon and Casseday, 1859 Figure 7


1859 Eretmocrinus magnificus Lyon and Casseday, p. 241.


1895a Batocrinus wetherbyi Miller and Gurley, p. 11, pl. 1, figs. 11, 12.


1895a Batocrinus commendabilis Miller and Gurley, p. 25, pl. 2, fig. 16.


1897 Eretmocrinus magnificus Lyon and Casseday; Wachsmuth and Springer, p. 386, pl. 37, fig. 3.


1958 Eretmocrinus magnificus Lyon and Casseday; Lane, p. 155.


1964 Eretmocrinus commendabilis Miller and Gurley; Van Sant, p. 116, pl. 7, fig. 12.


1978 Eretmocrinus magnificus Lyon and Casseday; N.G. Lane, p. T469, fig. 275.8a.


2013 Eretmocrinus magnificus Lyon and Casseday; Webster and Webster, p. 1420.


Complete synonymy list in Supplemental Data 2. Holotype.—USNM S 744a.


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