New finding of Mesozoic ephippia of the Anomopoda (Crustacea: Cladocera) Alexey A. Kotov* A.N. Severtsov Institute of Ecology and Evolution, Moscow, Russia (Received 6 November 2007; final version received 19 February 2008) Fossil Mesozoic anomopods (Crustacea: Cladocera) have only been found twice previously, although this group apparently differentiated in the Palaeozoic. This paper describes the finding of anomopod ephippia of three different types in the locality Khutel-Khara, Mongolia (Lower Cretaceous, 129¡9 Mya). This discovery demonstrates once more that the idea of rarity of cladocerans in Mesozoic fossils was motivated by insufficient attention of carcinologists to such fossils. Keywords: Cladocera; Crustacea; Anomopoda; Mesozoic; fossil Introduction Cladocera is a group of Palaeozoic origin (Fryer 1995; Dumont and Negrea 2002; Sacherova ´ and Hebert 2003; Forro ´ et al., 2008). Recently a series of new fossil taxa was described (Kotov and Korovchinsky 2006; Kotov 2009), including a new cladoceran order (Kotov 2007). But still each new Mesozoic finding is an important event for cladocerologists. The described Mesozoic cladocerans may be placed in five main groups: (1) family Sididae Baird, 1850 of the order Ctenopoda Sars, 1865; (2) family Leptodorosididae Kotov, 2007 of the order Cryptopoda Kotov, 2007; (3) family Prochydoridae Smirnov, 1992 with less clear phylogenetic position; (4) ephippia of family Daphniidae Straus, 1820 of the order Anomopoda Sars, 1865; and (5) undetermined claws possibly belonging to the Cladocera. Smirnov (1992) and then Fryer (1995) regarded prochydorids as anomopods, but Kotov (2007a) presented evidence that they form a specific lineage of cladocerans either separate from, or basal to the order Anomopoda. Unambiguous Mesozoic anomopods have been found only twice previously (Fryer 1991; Smirnov 1992). In this paper the third recorded finding of Mesozoic anomopod ephippia is reported. Materials and methods The available rock fragments from Khutel-Khara (Mongolia) from the collection of the Palaeontological Institute of the Russian Academy of Sciences (Moscow) were examined under stereo- and compound microscopes. Ephippia are found on rock fragments PIN 3965/3300, 3307, 3308, 3312, 3314, 3315, 3336, 3339, but no adult or juvenile specimens were found. All measurements were made under a compound microscope with exactly the right angle of observation, and only for ephippia with *Email: alexey_a_kotov@yandex.ru Journal of Natural History Vol. 43, Nos. 9–10, March 2009, 523–528 ISSN 0022-2933 print/ISSN 1464-5262 online # 2009 Taylor & Francis DOI: 10.1080/00222930802003020 http://www.informaworld.com