Fossils
White Springs Local Fauna
The Parachucla Formation (Porters Landing Member) in northern Florida is associated with the White Springs Local Fauna, consisting of fossils of 57 vertebrate species from the Arikareean stage of the late Oligocene epoch. The fossils of the White Springs Local Fauna have been collected from sites on an approximately 10 km long stretch along the Suwannee River where the Parachucla Formation is exposed. The local fauna includes a number of fossils of near-shore marine and land vertebrates, including 9 sharks, 5 rays, 14 bony fish, 6 reptiles, and 27 mammals. The reptiles include a marine crocodile, an alligator, a tortoise, and three snakes (a blind snake and two species of boas). The fossils of three sirenians ( Crenatosiren olseni, Dioplotherium manigaulti and a Metaxytherium species) have been found at those sites (White Springs is the holotype site for C. olseni [10] ). Rodents in the White Springs Local Fauna include species of the eomyid Arikareeomys and the cricetid Leidymys genera, the squirrels Protosciurus and Nototamias , and three species of geomyid rodents. Other small land mammals in the White Springs Local Fauna include a lagomorph ( Palaeolagus or Megalagus ), two bats, and a marsupial. Larger mammals include a horse ( Miohippus or Anchippus texanus ), an oreodont ( Mesoredon floridensis), three different camelids (including a Oxydactylus species), and a small rhinocerus (possibly a species of Diceratherium ). [11] [12]
Most of the land vertebrate fossils in the White Spring Local Fauna are teeth or post-cranial bones of smaller animals. Semi-articulated skeletons of larger mammals have been found at one location along the exposure. It is believed that the land vertebrate bones were carried into a delta or coastal lagoon by a river before burial. [13]
Invertebrate fossils
The dinoflagellates Sumatradinium soucouyantiae, Chordosphaeridium cantharellus, and Exochosphaeridium insigne are typical of the Parachucla Formation in Georgia. Cribroperidinium species are also common. [14]
Sixty-five taxa of invertebrates have been identified in the Porters Landing Member of the Parachucla Formation at the White Springs exposure in north Florida. Included in these are the bivalves Chlamys acanikos and Ostrea normalis and the barnacles Concavus crassostrictola, Balanus reflexus and a species of Solidobalanus . [15] [16]
Mammals
Color key
| Notes Uncertain or tentative taxa are in small text; |
| Sirenians | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Crenatosiren | C. olseni | White Springs Local Fauna of the Porters Landing Member [17] | A portion of a mandible was recovered from the White Springs site. [17] | A dugongid originally placed in the genus Halitherium. Partial skulls, mandibles, and ribs of C. olseni have been found in the Ashley and Chandler Bridge formations in South Carolina. [18] | |
| Metaxytherium | M. albifontanum | White Springs Local Fauna of the Porters Landing Member [19] | A skull, upper vertrabral column, and ribs were recovered from the White Springs site. [19] | A dugongid also found in the Chandler Bridge Formation. [19] | |
Fish
| Sharks | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Otodus | O. angustidens | A tooth (UF 17994). [20] | A megatoothed shark. |  | |
Invertebrates
| Crustaceans | |||||
|---|---|---|---|---|---|
| Genus | Species | Presence | Material | Notes | Images |
| Balanus | B. reflexus | Porters Landing Member. [21] | Scutum (UF 25603a). [22] | A balanid barnacle. | |
| Concavus | C. crassostricola | Porters Landing Member. [23] | 13 scuta, 1 tergum, 3 shells. [24] | A balanid barnacle. | |
| Solidobalanus | S. sp. indet. | Porters Landing Member. [25] | 2 scuta, disarticulated compartmental plates. [22] | An archaeobalanid barnacle. | |
