Casa Blanca
Basic information
Sample name: Casa Blanca
Sample aka: TMM 42486
Reference: J. W. Westgate. 1988. Biostratigraphic implications of the first Eocene land-mammal fauna from the North American coastal plain. Geology 16:995-998 [ER 4179]
Geography
Country: United States
State: Texas
County: Webb
Coordinate: 27° 32' N, 99° 26' W
Coordinate basis: stated in text
Scale: quarry
Formation: Laredo
Time interval: Middle Eocene
Zone: Uintan
Ma: 46.55
Age basis: AEO
Geography comments: "an exposure in the high-water spillway on the southeast side of Lake Casa Blanca... 2.5 km due east of the Laredo International Airport"
the quarry is "just above the middle" of the formation and "within the boundaries of the upper Lutetian and lower Bartonian beds" based on correlation with the Cook Mountain Formation "of east and central Texas" to the northeast
the quarry is "just above the middle" of the formation and "within the boundaries of the upper Lutetian and lower Bartonian beds" based on correlation with the Cook Mountain Formation "of east and central Texas" to the northeast
Environment
Lithology: sandstone
Taphonomic context: fluvial deposit
Habitat comments: the formation "locally is composed of marginal marine sand, clay, and marl" and the fossiliferous level is a sandstone lens within a siltstone unit according to Fig. 1, but this is said to be "an oyster shell hash" by Walton (1993a)
Methods
Life forms: carnivores,primates,ungulates,marine mammals,other small mammals
Sampling methods: quarry,screenwash
Sample size: 116 specimens
Museum: Texas Memorial Museum
Sampling comments: fossils were collected by "excavations" and screenwashing, with "approximately 3,000 kg of matrix" washed using "nylon bag mesh" and another 2,000 kg using coarser "window screen"
detailed taxonomic accounts of the same taxa and the same counts are provided by Westgate (1990)
there are at 10 nine rodent species in total, of which Mytonomys robustus is enumerated in the 1988 and 1990 papers; Laredomys riograndensis was described by Wilson and Westgate (1991); Pauromys sp. and Pauromys simplex were described by Walton (1993a); and Microeutypomys karenae was described by Walton (1993b)
this leaves Thisbemys sp., Microparamys sp., two ischyromyids, and a cylindrodontid without counts, making it impossible to include the rodents as a group in the inventory
detailed taxonomic accounts of the same taxa and the same counts are provided by Westgate (1990)
there are at 10 nine rodent species in total, of which Mytonomys robustus is enumerated in the 1988 and 1990 papers; Laredomys riograndensis was described by Wilson and Westgate (1991); Pauromys sp. and Pauromys simplex were described by Walton (1993a); and Microeutypomys karenae was described by Walton (1993b)
this leaves Thisbemys sp., Microparamys sp., two ischyromyids, and a cylindrodontid without counts, making it impossible to include the rodents as a group in the inventory
Metadata
Sample number: 4641
Contributor: John Alroy
Enterer: John Alroy
Created: 2025-01-06 09:09:44
Modified: 2025-01-06 09:09:44
Abundance distribution
20 species
5 singletons
total count 116
geometric series index: 33.4
Fisher's α: 6.967
geometric series k: 0.8460
Hurlbert's PIE: 0.9055
Shannon's H: 2.6301
Good's u: 0.9570
Each square represents a species. Square sizes are proportional to counts.
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Register
| †Peratherium comstocki | 3 | |
| Peratherium marsupium = †Herpetotherium marsupium | 4 | |
| †Simidectes cf. magnus | 1 | |
| †Centetodon pulcher | 5 | |
| Omomys sp. | 10 | |
| †Macrotarsius cf. jepseni | 1 | |
| Microsyops sp. | 11 | |
| Miocyon sp. | 1 | |
| cf.: "cf. Uintacyon sp."; compared to Uintacyon scotti, which is the genotype of Miocyon | ||
| †Procynodictis cf. vulpiceps | 1 | |
| Mesonychidae indet. | 2 | |
| †Hyopsodus cf. uintensis | 3 | |
| Sirenia indet. | 1 | |
| †Epihippus cf. gracilis | 12 | |
| †Amynodon advenus | 5 | |
| Brontotheriidae indet. | 6 | |
| †Laredochoerus edwardsi | 6 | |
| Westgate (1994): type; "Leptochoeridae indet." | ||
| †Protoreodon petersoni | 8 | |
| †Leptoreodon pusillus | 3 | |
| †Leptoreodon leptolophus | 24 | |
| †Toromeryx marginensis | 9 | |