Clarella venusta

• Main Authors: Unger, Tanja, Hildenbrand, Anne, Stinnesbeck, Wolfgang, Austermann, Gregor
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2022
• Subjects: Biodiversity; Taxonomy; Animalia; Arthropoda; Trilobita; Redlichiida; Centropleuridae; Clarella; Clarella venusta; Canada; Hicks; Manuels River; Newfoundland
• Online Access: https://doi.org/10.5281/zenodo.7477310; http://treatment.plazi.org/id/03DA87B6FF8D4956FEBC7E7EFB88F9FF

Clarella venusta (Billings, 1872) (Fig. 16) Anapolenus venustus Billings, 1872: 474-476, fig.11;1874: 73, 74, fig.42. Clarella venusta – Hutchinson 1962: 111, 112, pl. 17, figs 7-10. — Martin & Dean 1988: 19, pl. 1, fig. 13. — Whittington et al. 1997: figs 308.1a, b. — Fletcher 2006: pl. 34, fig. 11 ( partim ). LECTOTYPE. — Specimen GSC No. 284a, Geological Survey of Canada, Ottawa, Canada, designated as lectotype by Whittington et al. (1997). From Chapel Arm, Trinity Bay, Newfoundland, Canada. DIAGNOSIS. — Glabella not reaching anterior margin; L4 short; eye lobes from L1 to S4; pygidium with two pairs of short marginal spines. MATERIAL EXAMINED. — Three cranidia of Clarella venusta (NFM F-3069; NFM F-3548; NFM F-3657). All specimens range between 16.25 and 16.27 m (Fig. 2) within the Manuels River Formation, type locality, Conception Bay South, Newfoundland, Canada. OCCURRENCE. — Clarella venusta is rare in the middle Cambrian and only reported from southeastern Canada, eastern Newfoundland, in the Paradoxides hicksi and Paradoxides davidis zones (Hutchinson 1962; Martin & Dean 1988; Fletcher 2006). DESCRIPTION The cranidium (NFM F-3096) is 22.2 mm in width and 15.8 mm in length. The width of the glabella is 10.3 mm and the length is 10.8 mm. Due to the preservation of NFM F-3548; NFM F-3657 a solid measurment was not possible. The three cranidia are preserved as one disarticulated internal cast and two moulds. REMARKS The cranidium of Clarella venusta is similar to Clarella impar (Hicks, 1872). The palpebral lobes of C. venusta are narrower and curved more sigmoidally than those of C. impar (Cook, 1997). The librigena illustrated by Fletcher (2006: pl. 34, fig. 12) is disarticulated and its suture of the librigena does not match that of C. venusta . It is here excluded from the species. Published as part of Unger, Tanja, Hildenbrand, Anne, Stinnesbeck, Wolfgang & Austermann, Gregor, 2022, Biostratigraphy and taxonomy of polymerid trilobites of the Manuels River Formation (Drumian, middle ...