Conocrinus cahuzaci Roux & El��aume & Am��ziane 2019, n. sp

Autor: Roux, Michel, El��aume, Marc, Am��ziane, Nadia
Rok vydání: 2019
Předmět:
DOI: 10.5281/zenodo.5940618
Popis: Conocrinus cahuzaci n. sp. Fig. 5 I���K, Tables 5���6. Synonymy. Tormocrinus (g) Roux et al. 2006: 267, table 1. Etymology. Species dedicated to Bruno Cahuzac (University of Bordeaux), who collected a crinoid fauna (including the type series) that is more diversified than previously expected during his investigations of Eocene sediments in southwest France. Type locality and type stratum. Miretrain quarry; dark grey marls C6a of Roux et al. (2006), Bartonian (base NP17) at Angoum�� near Dax, southwest France. Material. Four aboral cups, including the holotype (MNHN.F. A69935) and three paratypes (MNHN.F. A69936). Quantitative parameters are listed in Tables 5 and 6. Diagnosis. Species with an abrupt enlargement of cup diameter at the level of basal/radial transition, five conspicuous and stout hypermorphic interradial processes, coarse and well-developed interradial ribs, ratio of central depression to radial ring diameter 0.44; arm articulatiom of muscular synarthry oval to semi-circular in inner position, ratio of arm socket to distal radial width 0.29. Description of holotype and paratypes. Aboral cup of the holotype has an abrupt enlargement of diameter at the level of the presumed basal/radial transition, five conspicuous and stout hypermorphic interradial processes of equal size (Fig. 5I), coarse and well-developed interradial ribs and a hemispherical central depression (Fig. 5J); ratio of central depression to radial ring diameter 0.44; arm articulatiom of muscular synarthry, oval to semicircular in inner position regarding outer edge of the radial circlet (Fig. 5K), ratio of arm socket to distal radial width 0.29. Two paratypes (A and C) with five shorter interradial processes of equal size, and the third (B) with one interradial process substantially longer than others. Remarks. Cups of Conocrinus cahuzaci n. sp., one of the paratypes of C. duperrieri, C. thorenti and C. veronensis share a rounded to semi-circular arm socket in inner position. Conocrinus archiaci differs in having a trapezoidal socket adjacent to the outer edge of the radial circlet. Interradial processes are substantially less developed in C. duperrieri and C. thorenti.
Published as part of Roux, Michel, El��aume, Marc & Am��ziane, Nadia, 2019, A revision of the genus Conocrinus d'Orbigny, 1850 (Echinodermata, Crinoidea, Rhizocrinidae) and its place among extant and fossil crinoids with a xenomorphic stalk, pp. 51-84 in Zootaxa 4560 (1) on pages 76-77, DOI: 10.11646/zootaxa.4560.1.3, http://zenodo.org/record/2627372
{"references":["Roux, M., Cahuzac, B. & Sztrakos, K. (2006) Les paleoenvironnements eocenes a Crinoides pedoncules des marnes de Miretrain (Angoume, SW de la France): interpretations paleobathymetriques. Comptes Rendus Geoscience, 338 (4), 262 - 271. https: // doi. org / 10.1016 / j. crte. 2006.01.001"]}
Databáze: OpenAIRE
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