. Bulletin of the British Museum (Natural History), Geology. LATE CAMPANIAN-MAASTRICHTIAN ECHINOIDS 159 some specimens smaller than 12 mm in this species, they could possibly turn out to be juveniles of H. sphericus. However, the majority of specimens are larger than 12 mm and the distribution of the two species is also not the same. Whereas H. sphericus is found predominantly at Jebel Raw- dah, section 1, beds 3-4 and also in beds higher up the succession (bed 11) in section 2, as well as at the pycnodont level (bed 8) at Jebel Faiyah, H. paucituberculatus consis- tently occurs further down i
. Bulletin of the British Museum (Natural History), Geology. LATE CAMPANIAN-MAASTRICHTIAN ECHINOIDS 159 some specimens smaller than 12 mm in this species, they could possibly turn out to be juveniles of H. sphericus. However, the majority of specimens are larger than 12 mm and the distribution of the two species is also not the same. Whereas H. sphericus is found predominantly at Jebel Raw- dah, section 1, beds 3-4 and also in beds higher up the succession (bed 11) in section 2, as well as at the pycnodont level (bed 8) at Jebel Faiyah, H. paucituberculatus consis- tently occurs further down in the succession (basal beds of Jebel Buhays and Jebel Faiyah, and bed 8 in Jebel Rawdah, section 2). The two species are thus stratigraphically discrete. Genus NOETL1NGASTER Vredenburg, 1911 TYPE species. Protechinus paucituberculatus Noetling, 1897 by original designation. Remarks. Noetlingaster has previously been classified in the Stomechinidae on account of its imperforate tuberculation and dicyclic apical disc ( Fell & Pawson 1966). However, it has a single large primordial interambulacral plate at the adoral end of each interambulacrum and a tuberculation style very similar to that of Hattopsis. Primordial interambulacral plates this well-developed are known only in the Arbaciidae. Finally, juvenile forms of Noetlingaster are extremely similar in appearance to Hattopsis, differing only in having a more depressed test profile and more interambulacral tubercles at corresponding sizes. Given the marked similarity between Hattopsis and Noetlingaster in apical disc, tuberculation, interradial epistroma and pore-pair development, there seem strong grounds for placing Noetlingaster as an arbaciid. There are nine named species of Noetlingaster, all from the late Cretaceous. The type species N. paucituberculatus (Noet-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of
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