Erratencrinurus aff. trippi ( Edgecombe, Banks, and Banks, 1999a )

Lee, Dong-Chan, 2013, Late Ordovician trilobites from the Xiazhen Formation in Zhuzhai, Jiangxi Province, China, Acta Palaeontologica Polonica 58 (4), pp. 855-882 : 877

Erratencrinurus aff. trippi ( Edgecombe, Banks, and Banks, 1999a)

Fig. 9K–M, O, P.

Material.—One thoraco−pygidium, three cranidia, three pygidia, one free cheek, and one thorax (repository numbers: NIGP−152057–152061).

Remarks.—This species resembles Erratencrinurus trippi Edgecombe, Banks, and Banks, 1999a ( Edgecombe et al. 1999a: figs. 7A–E, G, H, 9I–L) from Tasmania. This species differs in having a straight fixigenal spine (directed moderately outwards in E. trippi ) and less densely−distributed smaller tubercles on cranidium. In Zhou and Zhen (2008: 247) which summarizes trilobite records of China, listed is only a single occurrence of Erratencrinurus , which is from Inner Mongolia and has recently been described by Zhou and Zhou (2006). Erratencrinurus (Erratencrinurus) ejinensis Zhou and Zhou (2006 : figs. 5E, G, I, J, M, 6A, D–F) differs from this species in having larger and more denser tubercles on cranidium; the cranidial tubercle formula of this species 1L−0, 2L−2, 1, 0, and 3L−3, 2, 1, 0, with large 3L−0 and that of E. (E.) ejinensis 1L−1, 2L−3, 2, 1, and 3L−3, 2, 1. The pygidia of E. (E.) ejinensis have 16 pleural ribs (see Zhou and Zhou 2006: fig. 6A, D−F), while those of this species have 11; the pygidia of both species lack tubercles on axial rings.

North American Erratencrinurus species differ in having much coarser tubercles on cranidium (see Lespérance and Desbiens 1995: figs. 3–14 for Erratencrinurus spicatus [ Tripp, 1974]), and a sagittal tubercle on pygidial axial rings (see Lespérance and Tripp 1985: fig. 5f, i, j for Erratencrinurus perceensis [Cooper in Schuchert and Cooper, 1930]). This species would be a new Erratencrinurus species that is first recorded from South China region (see Zhou and Zhou 2006: 386 for geographic distribution of Erratencrinurus species), but better preserved material is needed to officially name it.