A NEW FAMILY, GENUS, AND SPECIES OF LOBSTER (DECAPODA: ACHELATA) FROM THE GADVAN FORMATION (EARLY CRETACEOUS) OF IRAN

Abstract

Records of fossil decapod crustaceans from Iran are scarce. Forster and Seyed-Emami (1982) reported Eryma bedelta (Quenstedt, 1857) from the Aalenian (Middle Jurassic) in northern Iran. Garassino and Krobicki (2002, p. 56) noted the presence of the lobster Eryma von Meyer, 1840, from Iran. Garassino (personal commun., 2005) confirmed that this referred to the work of Forster and Seyed-Emami and noted that this was the only decapod occurrence in the country known to him. Toraby and Yazdi (2002) reported a portunid from the Miocene of the country in an abstract but we are unaware of a subsequent publication. Microcoprolites with an internal structure characteristic of decapods are known from the Jurassic of Iran (Bronnimann, 1977). Thus, the discovery of the remains of a remarkable macrurous decapod, recovered from a well core sampling the Gadvan Formation, is noteworthy. This unique specimen is the basis for description of a new family, genus, and species of palinuroid lobster. The Gadvan Formation, named by James and Wynd (1965), has its type locality in the Fars Province at Kuh-e-Gadvan, east-northeast from Shiraz, Iran. It is a part of the progradational Megasequence VI (Alavi, 2004) of deep-marine to shallow-shelf sediments. At the type locality, the formation consists of about 107 m of dark gray, argillaceous, bioclastic limestone interbedded with gray, green, and brownish yellow marl. Laterally, the formation grades into dark shale and argillaceous limestone in the Khuzestan Province, the area from which the decapod was collected. Specifically, the specimen was extracted from a well at latitude 31°18′ 13.3″N and longitude 47°47′28.6″E (Fig. 1), at a depth of 3,852 m in the lower calcareous shale of the lower part of the siliciclastic member of the Gadvan Formation. The unit is the lateral equivalent of the Zubair Formation in Iraq (James and Wynd, 1965 …