Home » PID2020-114381GB-I00 » Multicostate terebratulides (Brachiopoda, Early Jurassic) in the westernmost Tethys Ocean

Multicostate terebratulides (Brachiopoda, Early Jurassic) in the westernmost Tethys Ocean

Hesperithyris aff. sinuosa from the Marrajo (Murcia) Subbetic Range.

 Early Jurassic multicostate Terebratulida are substantiated in the Subbetic Domain and reported in the Iberian Range for the first time. Records of this clade are revised in the peri-Iberian platforms (Subbetic, Iberian Range, Gibraltar, North and NE Spain, Lusitanian basin) in order to evaluate their global pattern distribution across the Tethys Ocean. After a new tectonosedimentary analysis, marine swells are proposed as depositional scenarios for the assemblages containing Hesperithyris  aff. sinuosa  in the southernmost Subbetic paleomargin, sheding light to the intrincate paleogeography of this part from the Betic Range. In the Iberian Range, the same species and Merophricus ? fimbrioides  occurred in extensive flooding intervals arriving from the deepest marine populations. As results of taxonomic and paleobiogeographical analyses, two morphotypes, Merophricus – and Hesperithyris -type, are discriminated forming part of the westernmost Tethys migration route. It can be ascertained that their E-W Tethyan spreading was fulfilled for the Merophricus -type from the intra-Mediterranean basins to the westernmost arc of the Tethys Ocean, via the Betic–Gibraltar seaway, reaching the proto-Atlantic northwards (Lusitanian basin) and possibly the northern margin of the Iberian Massif and Western France. In contrast, Hesperithyris  aff. sinuosa  from the Iberian and Betic ranges correspond to the intra- and peri-Mediterranean Hesperithyris– type, with a different dispersal pattern. The only Lower Jurassic Hesperithyrys -type multicostate terebratulides reported in the boundaries of the NW-Boreal bioprovince derive from the Northeastern Iberian paleomargins, probably due to sporadic incursion events at transgressive episodes. The row of Subbetic epioceanic seamount stepping stones helped the Merophricus -type migration in the E-W Mediterranean route and their pivotal position facilitated the dispersal of both morphotypes via the epicontinental Iberian seaway. In the Subbetic, the Hesperithyris bearing assemblages are recorded in the Pliensbachian Lavinianum Zone (Portisi and Cornacaldense subzones) equivalent to the basal part of the Margaritatus Zone (Stokesi Subzone) from the Iberian Range where the same species is now recorded, thus correlating the Southern epioceanic paleomargins with the Eastern epicontinental platforms. The origin and dispersal of the Merophricus -type around the Si–Pl boundary concurred with the Western Tethys early pre-rifting stage, and the pre-Domerian drowning of Tethyan platforms is synchronically consistent with the origin and spreading of the Hesperithyris -type.

Cite as: Baeza-Carratalá, J. F., García Joral, F., and Tent-Manclús, J. E. (2025). Multicostate terebratulides (Brachiopoda, Early Jurassic) from the South and Eastern peri-Iberian paleomargins: paleobiogeographical and biostratigraphical perspectives in the westernmost Tethys Ocean. Journal of Iberian Geology, 28 p. https://doi.org/10.1007/s41513-025-00296-8


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