Augerinoichnus helicoidalis, a new helical trace fossil from the nonmarine Permian of New Mexico

New Mexico contains a significant record of trace fossil assemblages, in terms of both abundance and ichnodiversity, from Lower Permian nonmarine depositional settings. Most notable amongst these are the trace fossil assemblages in the Robledo Mountains Formation of the Robledo Mountains in Dona Ana County, southern New Mexico, as recognized by the recent proposal to designate this area as a national monument. These trace fossil assemblages formed on a tidal flat under largely nonmarine conditions (Mack and James, 1986; Hun et al., 1993; Lucas et al., 1995a 1998) and are dominated by the trackways of tetrapods and arthropods, yielding important information on the paleoecology, diversity and behavior of late Paleozoic arthropods (Braddy an Briggs, 2002; Minter and Braddy, 2006a), as well as evidence of specialized foraging strategies (Minter et al., 2006). Additional Lower Permian trace fossil assemblages occur at a number of localities in New Mexico and represent a variety of nonmarine depositional settings. The material described herein represents a new ichnogenus of helical burrow, named Augerinoichnus helicoidalis , and is recurrent across Lower Permian localities in New Mexico (Fig. 1). Augerinoichnus occurs in tidal flat settings from the Robledo Mountains Formation of the Robledo Mountains (Mack and James, 1986; Hunt et al., 1993; Lucas et al., 1995a, 1998), fluvio-deltaic coastal plain settings from the Robledo Mountains Formation of the Don ̃ a Ana Mountains in southern New Mexico (Lucas et al., 1995b), and floodplain sandflat settings from the Abo Formation of Can ̃ oncito de la Uva in the Joyita Hills of central New Mexico (Hunt et al., 1995), the McLeod Hills of central New Mexico (Lucas et al., 1995c), and the Fra Cristobal Mountains of central New Mexico (Lucas et al., 2005). The report of this new ichnogenus provides important paleoecological infor- mation on foraging strategies in nonmarine paleoenvironments, as well as further evidence for the occurrence of trace fossils in nonmarine settings similar to those considered indicative of deep marine depositional settings