Arrisdrift
Basic information
Sample name: Arrisdrift
Reference: Q. B. Hendey. 1978. Preliminary report on the Miocene vertebrates from Arrisdrift, South West Africa. Annals of the South African Museum 76(1):1-41 [ER 4046]
Geography
Country: Namibia
Coordinate: -28.56° S, 16.50° E
Coordinate basis: estimated from map
Time interval: Middle Miocene
Zone: MN4
Age basis: zone
Geography comments: "in terrace deposits at Arrisdrift on the Orange River"
coordinate estimated using the map in Fig. 1
"early middle Miocene (c. 16 m.y. old)" according to Hendey, meaning Langhian
17.5 to 17 Ma according to Pickford et al. (1996) based on correlation with "Faunal Set PIII of East Africa... and the basal part of Mammal Zone MN 04a of Africa", meaning Burdigalian
coordinate estimated using the map in Fig. 1
"early middle Miocene (c. 16 m.y. old)" according to Hendey, meaning Langhian
17.5 to 17 Ma according to Pickford et al. (1996) based on correlation with "Faunal Set PIII of East Africa... and the basal part of Mammal Zone MN 04a of Africa", meaning Burdigalian
Environment
Lithology: siliciclastic (mixed)
Taphonomic context: fluvial deposit
Habitat comments: "a poorly sorted fluvial gravel" with the fossils having been "transported by water in a high-energy environment. Only one instance is recorded of skeletal elements occurring in articulation"
"brackish water near the coast" based on the presence of serpulids, and from an "approximately 1 m thickness of interbedded clays, silts, sands, fine grits, gravels and conglomerates" that was "fluviatile" but "most of the time... a quiet, shallow pool" with fossils "deposited during a single depositional event", possibly meaning a flooding episode (Pickford et al. 1996)
"brackish water near the coast" based on the presence of serpulids, and from an "approximately 1 m thickness of interbedded clays, silts, sands, fine grits, gravels and conglomerates" that was "fluviatile" but "most of the time... a quiet, shallow pool" with fossils "deposited during a single depositional event", possibly meaning a flooding episode (Pickford et al. 1996)
Methods
Life forms: carnivores,rodents,ungulates,other large mammals,other small mammals,birds,snakes,turtles,other reptiles,frogs,fishes
Sampling methods: quarry
Sample size: 129 specimens
Sampling comments: "The fossils were discovered in a prospect pit (Pit 2 of Drill-line AD 8) in deposits being investigated by the Consolidated Diamond Mines of South West Africa (Pty) Ltd."
specimens are "in the Department of Cenozoic Palaeontology at the South African Museum, Cape Town"
see also Pickford et al. (1996, CRASP 322:991-996), who provide a revised list based on new collections but no counts
"varanids, snakes, and a giant bird, probably struthionid" are in the new collections
specimens are "in the Department of Cenozoic Palaeontology at the South African Museum, Cape Town"
see also Pickford et al. (1996, CRASP 322:991-996), who provide a revised list based on new collections but no counts
"varanids, snakes, and a giant bird, probably struthionid" are in the new collections
Metadata
Sample number: 4461
Contributor: John Alroy
Enterer: John Alroy
Modifier no: John Alroy
Created: 2024-11-14 06:35:26
Modified: 2025-08-24 01:49:49
Abundance distribution
24 species
6 singletons
total count 129
geometric series index: 47.5
Fisher's α: 8.685
geometric series k: 0.8518
Hurlbert's PIE: 0.8453
Shannon's H: 2.4307
Good's u: 0.9544
Each square represents a species. Square sizes are proportional to counts.
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Register
| Clariidae indet. | 2 | |
| minimum count: plus indeterminate, isolated fish vertebrate; consistent with "Pisces" ID of Pickford et al. | ||
| Anura indet. | 1 | |
| "frog or toad"; consistent with "Amphibia" ID of Pickford et al. | ||
| Serpentes indet. | 2 | |
| "snake vertebrae"; "Ophidea" in Pickford et al. | ||
| Crocodylus lloydi = †Rimasuchus lloydi | 6 | |
| Pickford et al. 1996: "Crocodylus ? niloticus"; minimum count | ||
| Geochelone namaquensis = †Namibchersus namaquensis | 2 | |
| Pickford et al. 1996: "Chelonia": minimum count | ||
| Aves indet. | 2 | |
| minimum count: "more than one species" | ||
| Myohyrax sp. | 3 | |
| Pickford et al. 1996: "Myohyrax cf. oswaldi"; minimum count: "many" are present | ||
| †Amphicyon giganteus | 1 | |
| Pickford et al. 1996: "Amphicyon cf. steinheimensis"; possibly also including "several" postcrania | ||
| Ysengrinia sp. | 2 | |
| Pickford et al. 1996: sajd to be new; assumed to include the "very large" taxon "Canoidea indet." (1 specimen) and "? Hemicyoninae indet." (1 specimen) | ||
| Felidae indet. | 1 | |
| Pickford et al. 1996: "? Metailurus sp." | ||
| Mustelidae indet. | 1 | |
| Pickford et al. 1996: "? Ischyrictis sp." | ||
| Carnivora indet. | 1 | |
| a supposed small canine: several other indeterminate carnivore fossils are present, and Pickford et al. 1996 list two Mustelidae indet. taxa | ||
| †Prohyrax hendeyi | 40 | |
| Pickford et al. 1996: "Prohyrax sp." said to be new; minimum count of "individuals" | ||
| Gomphotherium sp. | 5 | |
| Pickford et al. 1996: "Gomphotheriidae indet." | ||
| †Prodeinotherium hobleyi | 3 | |
| plus "many" indeterminate proboscideans | ||
| Dicerorhinus sp. | 8 | |
| minimum count | ||
| †Nguruwe kijivium | 1 | |
| Pickford et al. 1996: small "Suidae indet." | ||
| Lopholistriodon moruoroti = †Namachoerus moruoroti | 3 | |
| †Dorcatherium pigotti | 5 | |
| Pickford et al. 1996: "Dorcatherium cf. pigotti"; including "a few" postcrania (assumed to mean three plus) | ||
| Climacoceratidae indet. | 26 | |
| Pickford et al. 1996: "Climacoceras sp." said to be new; includes "less numerous maxillae and upper teeth" (assumed to mean four plus) | ||
| Homoiodorcas sp. | 8 | |
| Pickford et al. 1996: "Bovidae indet." including "several mandible fragments... and postcranial bones" of which three are specified: minimum of four inferred; also assume to include large "Pecora indet." (4 specimens) | ||
| Australagomys sp. | 2 | |
| Pickford et al. 1996: "Kenyalagomys sp." said to be new | ||
| Proheliophobius sp. | 2 | |
| Pickford et al. 1996: compared to; "?Bathyergoides sp." | ||
| †Apodecter cf. stromeri | 2 | |
| Pickford et al. 1996: "Paraphiomys pigotti"; plus "many" rodent incisors | ||