Talexirhynchia, a New Rhynchonellid Genus from the Jurassic Ethiopian Province of Jordan
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Talexirhynchia, a new rhynchonellid genus from the Jurassic Ethiopian Province of Jordan Howard R. Feldman, Mena Schemm- Gregory, Mark A. Wilson & Fayez Ahmad Paläontologische Zeitschrift Scientific Contributions to Palaeontology ISSN 0031-0220 Paläontol Z DOI 10.1007/s12542-013-0216-y 1 23 Your article is protected by copyright and all rights are held exclusively by Springer- Verlag Berlin Heidelberg. This e-offprint is for personal use only and shall not be self- archived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com”. 1 23 Author's personal copy Pala¨ontol Z DOI 10.1007/s12542-013-0216-y RESEARCH PAPER Talexirhynchia, a new rhynchonellid genus from the Jurassic Ethiopian Province of Jordan Howard R. Feldman • Mena Schemm-Gregory • Mark A. Wilson • Fayez Ahmad Received: 30 May 2013 / Accepted: 28 November 2013 Ó Springer-Verlag Berlin Heidelberg 2013 Abstract A new genus and species of a rhynchonellide scattered on a limy substrate, such as shells and rocks, brachiopod from the Jurassic of Jordan, Talexirhynchia could have served as an attachment site for juveniles. With kadishi gen. et sp. nov., is described. The specimens were increasing growth, the loss of the pedicle and a semi- collected from the Mughanniyya Formation (Callovian) of infaunal position resulted in an increasingly incurved Wadi Zarqa from alternating claystones, siltstones, and ventral umbo that concealed the foramen. marly limestones with minor dolomite, dolomitic lime- stone, and coquinas that represent the upper part of the Keywords Talexirhynchia Á Rhynchonellida Á Jurassic sequence in Jordan. The environment of deposition Brachiopoda Á Middle Jurassic Á Ethiopian Province Á was neritic; food supply and light were unlikely to have Jordan been limiting factors. The specimens are related to Ethio- pian-Somali taxa and are consistent with the endemism that Kurzfassung Eine neue rhynchonellide Brachiopoden- characterizes the rhynchonellide brachiopod faunas of the Gattung und––Art, Talexirhynchia kadishi gen. et sp. nov., Jurassic Ethiopian Province. Specimens of Talexirhynchia aus dem Jura von Jordan wird beschrieben. Die Exemplare lived with the umbo in an upright position directed toward wurden in der Mughanniyya Formation (Callovium) von the seafloor or with the dorsal valve slightly above the Wadi Zarqa gesammelt und kommen in abwechselnden ventral valve. Juveniles were attached to the seafloor by the Lagen von Tonsteinen, Siltsteinen und mergeligen Kalken pedicle; carbonate shell material as well as other debris mit geringen Anteilen an Dolomiten, dolomitischen Kalken und Coquinas vor, die die ju¨ngsten jurassischen Ablager- ungen Jordaniens repra¨sentieren. Die Schichten wurden in M. Schemm-Gregory: Deceased. neritischer Fazies abgelagert, die wahrschein reich an Howard R. Feldman: Biology Department, Lander College for Nahrungsangebot und Licht durchflutet war. Die gesam- Women, The Anna Ruth and Mark Hasten School, A Division of melten Exemplare sind mit a¨thiopischen-somalischen Taxa Touro College, New York, NY 10023, USA. verwandt und spiegeln den Endemismus wieder, der die H. R. Feldman (&) M. A. Wilson Division of Paleontology (Invertebrates), American Museum of Department of Geology, The College of Wooster, 944 College Natural History, New York, NY 10024, USA Mall, Wooster, OH 44691, USA e-mail: [email protected] e-mail: [email protected] M. Schemm-Gregory F. Ahmad Centro de Geocieˆncias e Departamento de Cieˆncias da Terra, Department of Earth and Environmental Sciences, Faculty of Universidade de Coimbra, Largo Marqueˆs de Pombal, Natural Resources and Environment, The Hashemite University, 3000-272 Coimbra, Portugal P.O. Box 150459, 13115 Zarqa, Jordan e-mail: [email protected] M. Schemm-Gregory Museu Geolo´gico, Laborato´rio Nacional de Energia e Geologia (LNEG), Rua Academia das Cieˆncias, 19, 1200-003 Lisbon, Portugal 123 Author's personal copy H. R. Feldman et al. rhynchonellide Brachiopodenfauna der jurassischen Africogryphaea costellata, Homomya hortulana, and Pho- A¨ thiopischen Provininz charakterisiert. Vertreter von ladomya lirata. Dating of the Jordanian formations is partly Talexirhynchia leben in senkrechter Position mit der Dor- based on ammonite zonation (for example, the Bull- salklappe gering ho¨her als die Ventralklappe und dem atimorphites bullatus Zone that occurs in the Mughanniyya Wirbel zum Meeresboden hin gerichtet. Juvenile Exemp- Formation) and partly upon molluscan assemblages (Af- lare waren mit dem Stiel an Schalenmaterial und anderem ricogryphaea costellata–Eligmus asiaticus Zone from the Schuttdebris, z.B. Schalen oder Steine, der auf dem Hamam Formation) where ammonites are sparse. Upon Meeresboden verteilt vorlag, festgehaftet. Mit zuneh- completion of the taxonomic studies of the Jordanian bra- mender Gro¨ße a¨nderte sich die Lebensweise in eine semi- chiopods, we will be able to correlate the Middle Jurassic infaunale Position, die zu einem Verlust des Stieles und strata across the Dead Sea Rift (DSR). For example, the eines sta¨ndig weiter gebogenen ventralen Wirbels bis hin Callovian Mughanniyya Formation in the Zarqa region of zu vollsta¨ndigen Bedeckung des Stiellochs, fu¨hrte. northwest Jordan, east of the DSR, will be compared with the Zohar and Matmor formations of southern Israel and Schlu¨sselwo¨rter Talexirhynchia Á Rhynchonellida Á Gebel Minshera, Egypt, west of the DSR, as well as with the Brachiopoda Á Mittel-Jura Á A¨ thiopische Provinz Á Arroussiah Formation of Gebel El-Maghara, northern Sinai, Jordanian Egypt. The Mughanniyya Formation is correlative with the lowermost part of the Zohar Formation in the Negev that is coeval with the lowermost part of the Arroussiah Formation Introduction in Sinai, Egypt. The first geological studies in this region were completed by geologists exploring the region for petroleum (Picard Geographic and geologic setting and Hirsch 1987). However, fossils belonging to the Jurassic Ethiopian Province have been collected as early as The Levant, from where this material was collected, is the late nineteenth century from Saudi Arabia (Mollet part of the elevated platform terrain of the Arabian 1871), as well as geographically widespread areas such as Nubian Shield that is covered by intermittent Palaeozoic Somalia (Muir-Wood 1935; Weir 1925, 1929), Egypt to Cenozoic sedimentary successions consisting mainly of (Douville´ 1916) and the Cutch, India (Kitchin 1900). The clastic units with marine carbonates increasing upward Jurassic macrofossil fauna from Jordan, mainly brachio- (Rybakov and Segev 2005). At the onset of the Mesozoic pods and molluscs, collected in this period was later this area consisted of broad sea-marginal flats, analogous described by Cox (1925) and Muir-Wood (1925). Begin- to modern sabkhas, in which evaporites and dolomites are ning in the mid twentieth century brachiopod workers have found, whereas in the Early Jurassic, emergence led to studied these faunas from a more modern point of view subaerial exposure that was accompanied by extensive (Cooper 1989; Dubar 1967; Farag and Gatinaud 1960a, b; freshwater runoff and subaerial weathering (Goldberg and Feldman et al. 2001). Brachiopods and related faunas from Friedman 1974). Shallow and marginal shelf environ- northern Sinai have been studied by Feldman (1987), ments interrupted by lagoons resulting in the deposition of Feldman and Owen (1988), Feldman et al. (1982) and thick, partly calcareous sandstones that were overlain by Hirsch (1979) and those from Jordan by Feldman et al. thick, partly gypsiferous carbonates, marls, and sandy (2012) and are currently under study. In general, the bra- marls that can be observed as a result of subsequent chiopods from the Ethiopian Province typically show a subsidence and faulting of the Dead Sea Rift (Basha high degree of endemism typified by genera such as 1980). Daghanirhynchia, Somalirhynchia, Somalithyris, Biheni- The Jurassic strata samples crop out in northwestern thyris and Striithyris, but despite the work by Muir-Wood Jordan along the western part of Wadi Zarqa beginning (1925, 1935), Hegab (1988, 1989, 1991a, b, 1992, 1993), near the old Jerash Bridge and extending westward to Deir- and Cooper’s (1989) monograph, the Middle Jurassic bra- Alla, a distance of about 20 km (Fig. 1); toward the south chiopod fauna of this region is still poorly studied. the outcrop belt passes through Ain-Khuneizir, Subeihi, Bivalves from northwest Jordan have been collected and and Arda Road (Ahmad 2002a, b). The Jurassic succession will be used in paleoecologic studies to determine the nature decreases in thickness from the Zarqa River and Wadi Huni of the marine communities of the Middle Jurassic in the eastward toward the Zarqa Bridge and from there southeast region. Examples of abundant bivalves collected from the toward Suweileh-1 and Safra-1. In the Zarqa River vicinity study area in Jordan include: Gryphaeligmus jabbokensis, the estimated total thickness of Jurassic ranges between Africogryphaea costellata, Eligmus rollandi var.