‘Arctocyonids’ are generally considered as including some of the most primitive ‘ungulates’ from the Paleocene. Although more than 15 genera are known from North America, European members of this order are less common and mainly belong to derived genera such as Arctocyon. However, one species of primitive arctocyonid, Prolatidens waudruae, was described from the early Paleocene of Hainin, Mons Basin, Belgium. Here we describe new dental positions of this small taxon, including for the first time upper molars and upper fourth premolar. Morphological comparisons confirm the position of P. waudruae among primitive ‘ungulates,’ with the closest North American arctocyonids being Prothryptacodon furens and Oxyprimus galadrielae. Oxyprimus galadrielae features slightly more primitive morphological traits than both other species. Apheliscids share several characters with Prolatidens, but the latter lacks the apomorphies defining the family. Among ‘arctocyonids,’ Prolatidens shares with only Protungulatum and Oxyprimus the incomplete lingual cingulum at the base of the protocone of M1. Prolatidens waudruae is unique among Procreodi in its combination of primitive and derived characters. The cladistic analysis places P. waudruae close to the base of the ingroup, indicating that this species is among the most primitive members of the Paleocene ‘ungulates.’ However, the lower nodes of the trees are not well supported and definitive conclusions should await more complete specimens and analysis. Apheliscids are situated relatively far from Prolatidens, suggesting that the resemblances between them are better considered as convergences. Based on the morphological comparisons, the arctocyonid from Hainin correlates best with North American Torrejonian taxa.
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The New Caledonian Archipelago is a hot spot for biodiversity and endemism. Here, we report on new records of nine species from localities on the main island, Grande Terre, and illustrate these: Ilyodromus viridulus (Brady, 1886), Stenocypris hislopi Ferguson, 1969, S. macedonica Petkovski & Meisch, 1996¸ S. malayica Victor & Fernando, 1981, Bradleytriebella lineata (Victor & Fernando, 1981), Hemicypris pyxidata (Moniez, 1892), Heterocypris incongruens (Ramdohr, 1808), Cypridopis vidua (O.F. Müller, 1776) and Limnocythere stationis Vávra, 1891. We also provide redescriptions and illustrations of the valves and carapace of Stenocypris marginata Daday, 1910 sensu Méhes, 1939, Cypris granulata Daday, 1898 and Kennethia major (Méhes, 1939); for the latter species also including some soft parts. Therefore, twenty two certain species have thus far been reported from the New Caledonian Archipelago. The status of seven uncertain species is also discussed. Previous records of Stenocypris major (Baird, 1859) from Grande Terre, mainly by Méhes, are here considered to belong to S. hislopi. We propose to reject the presence of Cyprinotus cingalensis Brady, 1886 in New Caledonia and suggest to consider Cypridopsis sarasini Méhes, 1939 as an “uncertain species” (sensu Meisch et al. 2019). We also argue that Eucypris wolffhuegeli Méhes, 1914 might be a synonym of H. incongruens and suggest that Strandesia rouxi Méhes, 1939 might be considered a junior synonym of an existing species, pending further research.
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RBINS Staff Publications 2024
