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Journal of Paleontology 92(5):872–882
been formed as flat-lying, loose bioclastic sediments deposited on a shelf, generally below storm wave base. The crinoids reported here are from the widespread domi-
nant facies of the limestone, the Maerewhenua Member; this massive, little-cemented, light brown-yellow, bioclastic sand consists of fragments of mollusks, brachiopods, echinoderms, bryozoans, foraminiferans, and other invertebrates. (The Maerewhenua Member appears to be a senior synonym for the Meyers Pass Limestone Member of Eagle, 2007). Both the greensand and the limestone include notable
scattered shell beds. The highly friable limestone weathers easily, and fossils, most of which show little evidence of deformation or compaction, are easily extracted. Important fossils of marine vertebrates have been recovered from these units, including those of cetaceans (e.g., Fordyce and Marx, 2016), penguins (e.g., Ksepka et al., 2012), and fish (e.g., Gottfried et al., 2012). The units are also rich in marine macroinvertebrates, including bryozoans, corals, serpulids, brachiopods, mollusks, and echinoderms (see Eagle, 2007 for review), while common microfossils (foraminiferans and ostracods) provide excellent biostratigraphic constraints (Hornibrook et al., 1989; Ayress, 1993). According to microfossils and Sr/Sr dates, the Kokoamu Greensand and Otekaike Limestone span the local upper Whaingaroan, Duntroonian, and Waitakian stages, from low in the Chattian (27.82Ma to 23.03Ma) to possibly basal Aquitanian (23.03Ma to 20.44Ma).
Materials and methods
Repositories and institutional abbreviations.—Specimens described by Eagle (2007), all centrodorsals, collected at Ardlogie include AU19053-E868, AU19053-E869, GS11338.119–EC1162, GS11156.49-EC1163, GS11156.69- EC1164, GS11156.67-EC1165, GS11156.71-EC1166, and GS11156.18-EC1167, and at Haughs’ Quarry AU19054- E870A. A specimen (centrodorsal) collected at Haughs’ Quarry by A. Grebneff, OU44147; an intact specimen collected at ‘Waipati’ by R.E. Fordyce, OU46680. Four specimens of the type species of Cypelometra, Cypelometra iheringi (de Loriol, 1902): MACN4567—two specimens with same number collected at ‘Golfo San Jorge, Patagonia,’ one consisting of centrodorsal, the other of a centrodorsal and a radial ring; MACN4568 collected at ‘Bajo San Julian,’ consisting of a centrodorsal and a radial ring; MACN4569 collected at ‘Bajo San Julian,’ consisting of a centrodorsal and a radial ring. All specimens are housed in research collections inmuseums
in the following institutions: Department of Geology in the School of Geography, Geology andEnvironmental Science, University of Auckland,NZ(AU); Institute ofGeological andNuclearSciences, Lower Hutt, NZ (GS); Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia,’ Buenos Aires, ARG (MACN); Geology Museum, University of Otago, Dunedin, NZ (OU). Anatomical terms and abbreviations used follow Hess and
Messing (2011).
Systematic paleontology Class Crinoidea Miller, 1821 Subclass Articulata Zittel, 1879 Order Comatulida Clark, 1908
Superfamily Tropiometroidea Clark, 1908 Family Conometridae Gislén, 1924 Genus Rautangaroa new genus
Type species.—Cypelometra aotearoa Eagle, 2007, here designated by monotypy.
Included species.—Cypelometra aotearoa Eagle, 2007.
Diagnosis.—Genus of Conometridae with a large, pentastellate, truncated conical centrodorsal. Aboral pole large (40%–70%), flat to slightly concave cirrus-free rugose or granulated. Adoral
outline of centrodorsal deeply notched radially with triangular to blunt rectangular interradial projections. Subradial cleft present. Cirral sockets concave, moderately deep, and covered with radiating crenelae along the margins. Arms more than 20 divi- ded at primibrachial 2 (IBr2) and secundibrachial 2 (IIBr2); may divide further at tetribrachial 2 (IVBr2). Synarthries between brachials 1 and 2 of brachitaxes. Syzygies at IIIBr1–2 or IIIBr3– 4, and, when tetribrachials present, at IVBr1–2.
Etymology.—From the Māori words rau, meaning frond or feather, and tangaroa, meaning sea.
Occurrence.—Maerewhenua Member of the Otekaike Lime- stone, Oligocene: South Canterbury and North Otago, South Island, New Zealand.
Remarks.—The assignment of Rautangaroa to the Con- ometridae is based on the size and shape of its centrodorsal and the arrangement, size, and shape of its cirrus sockets. Its truncated conical centrodorsal with a flattened aboral apex, absence of a dorsal star, cirrus sockets arranged in 10 more or less distinct vertical columns of two to four sockets, separated by a naked space in the radii, a narrow centrodorsal cavity, concealed basals, and visible dorsal, free surface of radials are all traits found in Conometridae (Hess and Messing, 2011). Among the Conometridae, Rautangaroa most closely
resembles Cypelometra, but a detailed analysis of the type species of Cypelometra, C. iheringi (de Loriol, 1902), reveals significant differences. Gislén (1924) established the genus Cypelometra with
Antedon iheringi de Loriol, 1902 as the type species. In the original description, de Loriol relied on six specimens collected in Patagonia by C. Ameghino (Ameghino, 1906, p. 171) that had been sent to him by Ihering (de Loriol, 1902, p. 3, 23). de Loriol’s description included drawings of two specimens (de Loriol, 1902, figs. 3, 4). Until Eagle’s 2007 publication, C. iheringi (de Loriol, 1902) remained the only species of the genus, and specimens mentioned by de Loriol (1902) were the only ones reported in the literature. It is highly unlikely that subsequent to de Loriol’s 1902 publication, specimens of C. iheringi (de Loriol, 1902) had been reexamined since de Loriol did not specify where the types were deposited, and all subsequent authors relied solely on de Loriol’s descriptions, often republishing his figures. One of the original illustrations (de Loriol, 1902, fig. 3a)
shows deep radial pits or impressions on the adoral side of the centrodorsal. Surprisingly, this striking feature is not mentioned
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