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| Pseudocarcinus karlraubenheimeri van Bake & Ossó, 2024 Photographs by Jean-Claude Stahl (NMNZ) |
ABSTRACT
Large-sized extinct crab specimens recovered from Waitoetoe beach, North Island, New Zealand form the basis for a new species of ‘Southern Giant Crab’, Pseudocarcinus karlraubenheimeri n. sp. The specimens originate from the upper Miocene Urenui Formation (approximately 8.8 myr) of the Taranaki Basin, in which a series of volcanoes of the Mohakatino Volcanic Centre erupted offshore, leading to the formation of a specific palaeoenvironment. The well-preserved, articulated specimens were found buried in sediments which include reworked volcanogenic material. The crabs inhabited a deep-marine setting. This is the first evidence that Pseudocarcinus inhabited the region that is now New Zealand. New Zealand Miocene environments apparently offered favourable conditions in terms of food sources, metabolic requirements, and calcium-carbonate supply for Pseudocarcinus karlraubenheimeri n. sp. Pseudocarcinus thrived on both sides of the Tasman Sea until it disappeared in New Zealand waters. Pseudocarcinus crabs are characterised by gigantism, which provided them with significant advantages in competition and defence. Their carnivorous nature is reflected in their exceptionally large major cheliped. The broader use of benthic dwelling gastropods and bivalves as prey seems to have led to subsequent advances in brachyuran claw engineering, and an increase of molluscivorous crabs in the Late Cretaceous and Palaeogene.
KEYWORDS: Brachyura, Pseudocarcinidae, new species, Taranaki Basin, Urenui Formation, volcanic deposits
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| Pseudocarcinus karlraubenheimeri n. sp., A, holotype, NMNZ CR.027704, showing dorsal carapace, thoracic sternum and major right cheliped (male); B, detail of right major cheliped and thoracic sternum; B’, annotated detail of thoracic sternum, abbreviations: 4, 5, 6, thoracic sternites 4, 5 and 6; e4, e5, e6, episternites 4, 5 and 6; g4, g5, gynglyme of thoracic sternites 4 and 5; 4/5, 5/6, thoracic sternal sutures 4/5 and 5/6; ag, axial groove; og, oblique groove; pb, press-button for pleonal holding mechanism. Photographs by Jean-Claude Stahl (NMNZ). Scale bars equal 50 mm. |
Pseudocarcinus karlraubenheimeri n. sp.
Etymology. In honour of Karl Raubenheimer (New Plymouth, North Island, New Zealand), who collected and donated the holotype specimen described in the present study.
Barry W. M. van Bake and Àlex Ossó. 2024. A New ‘Southern Giant Crab’ from A Miocene continental slope palaeoenvironment at Taranaki, North Island, New Zealand. New Zealand Journal of Geology and Geophysics. DOI: 10.1080/00288306.2024.2314472