Thecal (oral zone) elements in cystoids from Spain

Cid, María Dolores Gil; Rincón, Juan Manuel García

doi:10.1127/0077-7749/2012/0238

Cited by 5 publications

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“…The new material described herein is deposited at the Museo Geominero of Madrid (MGM), which belongs to the Instituto Geológico y Minero de España (IGME-CSIC: the former Spanish Geological Survey), and where the originals of Meléndez (1951) and Gutiérrez-Marco (2000) are also preserved. The remaining illustrated material belongs to the palaeontological collection of the Department of Geodynamics, Stratigraphy and Palaeontology of the Complutense University of Madrid (DPM), corresponding to the papers of Chauvel and Meléndez (1978, 1984, 1986 and Gil Cid and García Rincón (2012).…”

Section: Repositories and Institutional Abbreviationsmentioning

confidence: 99%

Pentaradiate diploporites (Echinodermata) from the Spanish Middle Ordovician and their taxonomic significance

Paul

Gutiérrez-Marcos²

2022

Spanish J. Palaeontol.

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New Middle Ordovician pentaradiate diploporites from the southern Central Iberian Zone, Spain, show that Oretanocalix is an aristocystitid with fi ve ambulacra; all other aristocystitid genera have 2-4 ambulacra. The oral frame is composed of eight plates, with fi ve, facet-bearing, circumorals (COO) and three, non-facet-bearing, periorals (POO). This necessitates a new interpretation of the aristocystitid oral area. Previous interpretations assumed four COO and four POO. Weathered examples lack oral cover plates, show that CO1 and CO4 do not reach the peristome inner margin and reveal abundant diplopores covered by thin epistereom in life. Diplopores grew at plate sutures and were incorporated into both adjacent plates. The genus Batalleria is a sphaeronitid with food grooves that branched within the peristome. Branching refl ects Lovén's law and is: AR, BL, CR, DL, ER, where A-E denote Carpenter's ambulacra and L (left) and R (right) denote on which side the fi rst branch lies. Each branch has a separate ambulacral orifi ce. All other sphaeronitids have one ambulacral orifi ce per ambulacrum. Diagnoses of the genera Oretanocalix and Batalleria, and their type species O. murchisoni and B. batalleri, are revised. Oretanocalix julioi n. sp., from the Darriwilian of the Toledo Mountains, is the oldest representative of the genus.Resumen: Se presenta nuevo material de Oretanocalix y Batalleria, dos géneros de blastozoos diploporitos pentaradiados procedentes de la Zona Centroibérica meridional española. El primero se caracteriza por tener cinco ambulacros, en vez de los 2 a 4 conocidos en el resto de los aristocistítidos, y una teca con abundantes diploporos recubiertos por un epiestereoma delgado. En su zona oral se reconocen cinco placas circumorales (COO, con facetas) y tres periorales (POO, sin facetas), pero las placas CO1 y CO4, que soportan los ambulacros D y B, respectivamente, no alcanzan el margen interno del peristoma. Ello obliga a revisar la diagnosis de la familia Aristocystitidae, pues las interpretaciones previas consideraban el área oral formada por cuatro COO y cuatro POO. Por su parte, el género Batalleria es un esferonítido muy particular porque presenta surcos alimentarios ramifi cados dentro del peristoma, siguiendo el patrón de Lovén con la fórmula AR, BL, CR, DL, ER, más un orifi cio ambulacral separado para cada rama. Desde el punto de vista taxonómico se revisan también las especies atribuidas a ambos géneros, estableciéndose Oretanocalix julioi n. sp. como la forma más antigua, procedente de lutitas del Dobrotiviense basal (Darriwiliense superior bajo) de los Montes de Toledo centrales.

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Section: Repositories and Institutional Abbreviationsmentioning

confidence: 99%