First evidence of brachiopod diversification after the end-Triassic extinction from the pre-Pliensbachian Internal Subbetic platform (South-Iberian Paleomargin)

Abstract

Lower Jurassic brachiopods are widely known in the External Betic Zone. Their occurrence was so far virtually restricted to the easternmost Subbetic Zone where they underwent a diversity burst and radiation event during the late Sinemurian-early Pliensbachian interval, leading to a bloom in brachiopod diversity from the early Pliensbachian onwards. Taxonomical and paleobiogeographical analyses performed in a newly recorded assemblage from the most offshore areas of the Subbetic Basin (Granada province, Spain) reveals that this diversification event occurred earlier than expected hitherto, probably in the Turneri-Obtusum chronozones, as similarly observed in the most intra-Tethyan basins such as the Northern Calcareous Alps and Transdanubian Ranges, illustrating the recovery of the background conditions for the establishment of diversified brachiopod communities after the end-Triassic extinction event. A new rhynchonellide species, Alebusirhynchia vorosi nov. sp., is formally described among the ten different taxa recorded for the first time in this A c c e p t e d M a n u s c r i p t area. The Mediterranean paleobiogeographical affinities revealed by the brachiopod assemblage emphasizes that the onset of the Mediterranean/Euro-Boreal bioprovinciality and the initial brachiopod diversification in the pre-Pliensbachian Internal Subbetic platform took place earlier in the Sinemurian as well, following the Euro-Boreal monotypic record previously reported in this region.

The last representatives of the Superfamily Wellerelloidea (Brachiopoda, Rhynchonellida) in the westernmost Tethys (Iberian paleomargins) prior to their demise in the early Toarcian Mass Extinction Event

“…Salgirella alberti (Oppel, 1861) Figure 10 1861 Occurrence.-This species is frequently reported in the classical literature (e.g., Oppel, 1861;Geyer, 1889;Ormós, 1937). Among the numerous localities where S. alberti is recorded, notable are those from the Sinemurian from the Northern Calcareous Alps (Geyer, 1889;Vörös et al, 2003;Siblík and Lobitzer, 2008;Mandl et al, 2010) and Crimea and Caucasus (Moisseiev, 1934;Moisseiev in Berg et al, 1947); from the Hettangian-late Sinemurian of the Transdanubian Ranges (Dulai, 1993(Dulai, , 2003Vörös and Dulai, 2007); from the Pliensbachian of the Subbetic (Baeza-Carratalá, 2013;Baeza-Carratalá et al, 2018b); from the Pliensbachian of Turkey (Vörös, 2014) or the North African basins (Dareste de la Chavanne, 1920).…”

“…Description.-This species was recently exhaustively described and discussed in several western Tethys biochoremas (Dulai, 2003;Vörös and Dulai, 2007;Baeza-Carratalá, 2008;Vörös, 2014;Baeza-Carratalá et al, 2018b; among others) and well illustrated over the last decades, as can be deduced from the synonymy list, and does not need further detailed systematic external description, but its great intraspecific variability justifies an abridged description of S. alberti in the peri-Iberian paleomargins, thus substantiating our interpretation of this taxon. Betic material of this species corresponds to medium-sized Material.-Twenty-five articulated specimens in different states of preservation sampled from the Cerro de la Cruz, La Algueda, and Las Losillas outcrops in the External Subbetic; 6 fragmented specimens from the Internal Subbetic (Sierra Gorda); supplemented by 32 specimens from the JdC collection derived from Sierra de la Espada, Sierra de Quibas, Algayat, and Cerro Cruz Algueña.…”

“…5.2014 Salgirella alberti (Oppel); Vörös, p. 22, figs. 24–26.2018b Salgirella alberti (Oppel); Baeza-Carratalá et al, p. 374, fig. 4 (8–10).

Figure 10.Some representative Early Jurassic specimens of Salgirella alberti (Oppel, 1861) from the Subbetic paleomargin.

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“…In the peri-Iberian platforms system, the abundant record of Cirpinae in the Early Jurassic is represented by the genera Calcirhynchia , Cirpa , and Salgirella (e.g., Pérez-López et al, 1993; Alméras and Fauré, 2000; Comas-Rengifo and Goy, 2010; Comas Rengifo et al, 2013, 2015; Baeza-Carratalá, 2013). The genus Calcirhynchia seems to be restricted to the Sinemurian–lowermost Pliensbachian deposits (Pérez-López et al, 1993; Baeza-Carratalá, 2013; Baeza-Carratalá et al, 2014, 2018b), while the prolific occurrence of Cirpa and Salgirella throughout the entire Early Jurassic was suddenly terminated by the onset of the ETMEE, even by the Pliensbachian-Toarcian transition. The present paper clarifies the complex systematics of the Lower Jurassic rhynchonellides, unravelling the record of the last representatives of the Superfamily Wellerelloidea worldwide.…”

Análisis de elementos traza en braquiópodos del Jurásico Inferior del Paleomargen Sud-Ibérico (SE de España). Correlación con las señales bióticas e implicaciones ambientales en torno al Evento de Extinción Masiva del Toarciense inferior

“…The homogeneous platform system, established in the Western Tethys during the earliest Jurassic, subsequently drowned related to the Central Atlantic Ocean opening (Bernoulli & Jenkyns, 1974;Winterer & Bosellini, 1981). After an earlier diversification stage probably ongoing from the early Sinemurian (Baeza-Carratalá et al, 2018b), a speciation burst and radiation event during the Sinemurian-Pliensbachian transition (Raricostatum-Aenigmaticum zones) led to a bloom in brachiopod diversity from the late Sinemurian onwards. This peak of prosperity was probably related to an incipient pre-rifting stage of the westernmost Tethyan platform system.…”