On the Systematic Position of Ferganotoechia Rzhonsnitskaia, 1978 (Rhynchonellida, Brachiopoda)
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he Systematic Position of Ferganotoechia Rzhonsnitskaia, 1978 (Rhynchonellida, Brachiopoda) A. V. Pakhnevich* Borissiak Paleontological Institute, Russian Academy of Sciences, Moscow, 117647 Russia *e-mail: [email protected] Received December 17, 2018; revised April 8, 2019; accepted April 8, 2019
Abstract—The holotype and topotypes of Camarotoechia ferganica Nalivkin, 1930 are restudied. This species was erected based on a single complete shell, and subsequently assigned by M.A. Rzhonsnitskaya to the genus Ferganotoechia Rzhonsnitskaya in Rzhonsnitskaya, Kulikova et Petrosyan, 1978. However, the generic diagnosis was not published earlier. Here the shell interior of F. ferganica is first described, and its generic diagnosis is suggested. The genus is assigned to the subfamily Trigonirhynchiinae of the family Trigonirhynchiidae. Keywords: brachiopods, Rhynchonellida, Trigonirhynchiinae, Ferganotoechia, micro-CT DOI: 10.1134/S0031030120050123
The collections of Russian institutes and museums contain many original and type specimens of brachiopods, often from the 19th century, that have not been restudied for many decades. Some of them, including rhynchonellids, were considered as nomina dubia in the last edition of the Treatise (Savage et al., 2002; Savage, 2006). Therefore, it is very important to restudy old brachiopod collections in the light of current taxonomic knowledge, particularly brachiopods with poorly known or completely unknown shell interiors. In the rhynchonellid collections of D.V. Nalivkin I found a shell of the interesting Devonian species Camarotoechia ferganica Nalivkin, 1930 from the Eifelian of West Fergana. This species has an unusually large shell for a Devonian rhynchonellids brachiopod. The shell exterior was first described by Nalivkin (1930); the shell interior was previously unknown. Only the holotype preserved, no further specimens are known. In 1978 C. ferganica was made the type species for the new genus Ferganotoechia (Rzhonsnitskaya et al., 1978, 1982). These authors did not redescribe the species or provide a diagnosis of a new genus; the shell interior was not illustrated. The location of the additional collection from which M.A. Rzhonsnitskaya described the material was unknown. Thus, a poorly known species based on a single specimen became the type species of a genus and was subsequently correctly regarded as nomen dubium (Savage, 2002). Here the holotype of the type species is restudied using X-ray microtomography; in addition, traditional cross sections through the shells of F. ferganica collected by Rzhonsnitskaya in the topotypic region were made.
MATERIAL AND METHODS The holotype of Camarotoechia ferganica was found in the Eifelian deposits of West Fergana (Middle Asia), left bank of the Shakhimardan River, approximately 3 km downstream from the village of Shakhimardan, and is currently housed in the Chernyshev Central Research Geological Prospecting Museum, St. Petersburg (TSNIGR Museum, no. 901/94). The additional material consists of one complete shell, three ventral valves
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