Clarella Howell 1933

Genus Clarella Howell, 1933 Clarella Howell, 1933: 219. — Type species: Anapolenus venustus Billings, 1872, designated as lectotype by Howell (1933). DIAGNOSIS. — Glabella with great forward expansion anterior of S1; palpebral lobes slightly sigmoidal, reaching almost genal angle; thorax with 15 segments; pygidium without border, up to four pairs of marginal spines; short axis with one to two axial rings (based on Howell 1933; Whittington et al. 1997, with modifications). REMARKS Clarella is distinguished from Anapolenus Salter, 1864a by sigmoidally shaped palpebral lobes that almost reach the genal angle. The palpebral lobes of Anapolenus curve in a uniform arc, reaching the genal angle. The pygidium of Clarella lacks a border, while that of Anapolenus is bordered (Howell 1933; Whittington et al. 1997).
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 Cambrian), Newfoundland, Canada, pp. 1051-1087 in Geodiversitas 44 (33) on page 1075, DOI: 10.5252/geodiversitas2022v44a33, http://zenodo.org/record/7477657
{"references":["HOWELL B. F. 1933. - The classification of the trilobite Subfamily, Centropleurinae. Meddelelser fra Dansk Geologisk Forening 8 (3): 215 - 219.","BILLINGS E. 1872. - On some fossils from the primordial rocks of Newfoundland. Canadian Naturalist and Quarterly Journal of Science 6: 465 - 479. https: // doi. org / 10.5962 / bhl. title. 38279","WHITTINGTON H. B., CHATTERTON B. D. E., SPEYER S. E., FORTEY R. A., OWENS R. M., CHANG W. T., DEAN W. T., JELL P. A., LAURIE J. R., PALMER A. R., REPINA L. N., RUSHTON A. W. A., SHERGOLD J. H., CLARKSON E. N. K., WILMONT N. V. & KELLY S. R. A., 1997. - Treatise on Invertebrate Paleontology, Part O, Arthropoda 1, Trilobita, Revised. Geological Society of America and University of Kansas, Boulder, Colorado, and Lawrence, Kansas, 530 p.","SALTER J. W. 1864 a. - On some new fossils from the Lingula-flags of Wales. The Quarterly Journal of the Geological Society 20: 233 - 241. https: // doi. org / 10.1144 / gsl. jgs. 1864.020.01 - 02.33"]}