962
Journal of Paleontology
Figure 6. Isolated sclerites of Allonnia tenuis n. sp. (1) YN-GLF-PAL-12; (2) YN-GLF-PAL-09. White arrows point to the internal cavity of a lateral ray. Scale bars=1mm.
Among articulated scleritomes, most are laterally compacted, so the orifice cannot be discerned clearly. Only Al. tintinopsis, from the middle Cambrian Burgess Shale, clearly shows the morphology and features of the apical orifice (Bengtson and Collins, 2015, fig. 21). Likewise, most of the articulated scleritomes of chancelloriids from the early Cambrian, such as those found in the Chengjiang Lagerstätte, are preserved laterally, and no clear features of the apical end can be seen. Only one specimen of Allonnia junyuani Janussen et al., 2002 (synonymous with Al. phrixothrix Bengtson and Hou, 2001) is compacted top-down and shows some sclerites radially arranged at the apical end (Kloss et al., 2009). Hitherto, all known specimens of chancelloriids from the Guanshan Biota (e.g., Luo et al., 2008; Hu et al., 2013) are compacted laterally and the apex is densely ornamented with sclerites. YN-GLF-PAL-03 (Fig. 7.4) is the first specimen clearly showing the structures of the apical orifice in chancelloriids from the Guanshan Biota which is morphologically similar to that of Al. tintinopsis (e.g,. Bengtson and Collins, 2015, figs. 21, 26). These observations confirm that the apical orifice, connecting the internal body cavity with the outside environment, is an integral part in chancelloriids (especially Allonnia from both early and middle Cambrian).
Phylum uncertain
? Order Chancelloriida Walcott, 1920 Genus Nidelric Hou et al., 2014
Type species.—Nidelric pugio Hou et al., 2014.
Diagnosis.—Chancelloriid-like metazoan with a subovoid body profile; spines are single-element, triangular, and outward pro- jecting. Spine surface devoid of any ornament or bearing trian- gular scales that are absent from the spine base.
Nidelric gaoloufangensis new species Figures 9–14
Holotype.—The specimen of YN-GLF-PAL-17 (Fig. 9.1) is hereby designated as the holotype for this species. The holotype specimen is found in Cambrian Series 2, Stage 4, Palaeolenus Zone, Wulongqing Formation, Gaoloufang section, Kunming City, Yunnan Province, China.
Diagnosis.—Small species of Nidelric bearing single-element spines; body profile subovoid with the apical end narrowest; a tuft-like structure, formed by at least four oriented spines with their tips projecting towards the axis of the body, is located at the apical end; both ends gently curved; spine surface devoid of any ornament.
Description.—Nidelric gaoloufangensis n. sp. is subovoid in general body profile, with the upper end narrower than the lower end (Figs. 9.1, 10.1). Height ranges from 11mm (YN-GLF- PAL-98, Fig. 11.2) to 24mm(YN-GLF-PAL-18, Fig. 10.1) and the greatest width (at the center of the body) ranges from 4mm to11mm. Different body profiles also exist (e.g., YN-GLF- PAL-99 is slenderer than others, with the margin in the center area being depressed to some extent, Fig. 10.2; YN-GLF-
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