Permian Trilobites from Antalya Province, Turkey, and Enrollment in Late Palaeozoic Trilobites

Trilobites are a minor component of Permian benthic marine faunas, which explains why they remain poorly known. For example, only two specimens have been found in the highly fossiliferous and extensively studied Middle-Upper Permian Pamucak Formation (Antalya Province, Turkey). These two complete enrolled trilobites of Wordian age are described herein. The diagnosis of the subgenus Pseudophillipsia (Nodiphillipsia) Kobayashi & Hamada 1984a is emended and its occurrence outside of eastern Asia is reported for the first time. The second specimen represents a new species, Pseudophillipsia (Carniphillipsia) kemerensis sp. nov. Its discovery in the Wordian of Turkey suggests that Pseudophillipsia (Carniphillipsia) is no less diversified in the Middle Permian than in the Early Permian. Both specimens exhibit a particular enrollment posture, with the anterior part of the pygidium located within the cephalic cavity, while its posterior part is adpressed against the anterior cephalic doublure. The advantages of this style of enrollment are discussed, especially with regards to resistance of the enrolled body to external pressures, and rare examples of similar postures in older trilobites are reported. These two specimens are the first Permian trilobites from Turkey to be described, thus complementing the poor fossil record of these organisms in the Permian of southwestern Asia.