Evolutionary patterns in macrurous decapod crustaceans from Cretaceous to early Cenozoic rocks of the James Ross Island region, Antarctica

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Abstract
The fossil record of macrurous decapod crustaceans is unusually rich in the Late Cretaceous to Paleocene rocks of the James Ross Island region, Antarctica. Four species of lobsters, contained in four genera, are known from the region. Hoploparia stokesi (Weller) is most abundant and has been collected on James Ross, Vega, Humps, Cockburn, Seymour, and Snow Hill islands from early Campanian through Paleocene rocks. Whereas morphometric analysis of the species shows no evolutionary trends in shape, carapace ornamentation and claw ornamentation become more variable higher in the section. Metanephrops jenkinsi Feldmann, has also been identified. Metanephrops has previously been known from only one fossil occurrence, in the Pliocene of New Zealand. Its occurrence on Seymour Island may lie within the region of origin of this taxon which currently inhabits deep water, lower latitude habitats in the Atlantic and Indo-Pacific oceans. Metanephrops jenkinsi is known in the early Campanian Santa Marta Formation, in the Maastrichtian portion of the Lopez de Bertodano Formation, and in the Paleocene Sobral Formation. Other taxa are less abundant. In early to middle Campanian rocks on James Ross Island, Meyeria crofti Ball represents a relatively late occurrence of a conservative group. Linuparus macellarii Tshudy & Feldmann represents the highest latitude occurrence of a species within this genus, which is known from numerous Cretaceous and Paleogene sites in the Northern Hemisphere but from only two other fossil occurrences in the Southern Hemisphere. This species ranges from the early to middle Campanian into the Paleocene. There is no apparent effect of the K/T boundary ‘event’ on the decapod fauna. New taxa appear below the K/T boundary and none of the Antarctic species disappear from the record at that time.