Candelaria Hills, eastern portion (Triassic of the United States)

Where: Esmeralda County, Nevada (38.1° N, 118.0° W: paleocoordinates 11.8° N, 41.2° W)

When: Candelaria Formation, Dienerian (252.2 - 251.3 Ma)

• At the study site, the outcrop is not well exposed and covered by scree, except in a few shallow, seasonal stream channels, thus preventing the measurement of a stratigraphic section. Based on observations of in situ collected material, the bedding plane is nearly parallel to the local topography, so that all specimens are assumed to originate from a single horizon. A few external molds of ammonoids occur with the fishes (e.g., PIMUZ A/I 4730), but they are either indeterminable juveniles or poorly preserved. At the study sites of Ware et al. (2011), isolated bones (PIMUZ 35926) were found together with the late middle Dienerian (sensu Ware et al., 2015) A. lilangensis fauna, and it is probable that the fishes described herein are from the same horizon. The fishes clearly come from the lower Candelaria Formation, which is middle to late Dienerian in age (late Induan, early Early Triassic).

• bed-level stratigraphic resolution

Environment/lithology: offshore; lithified, concretionary, carbonaceous shale

• The lower Candelaria Formation was deposited in a moderately deep outer shelf setting, in a basinal trough characterized by high sedimentation rates (Poole and Wardlaw, 1978). The dark, laminated, organic-rich shale is indicative of oxygen-depleted bottom waters.
• The fishes from the Candelaria Formation are preserved as external molds in silicified, early diagenetic concretions. The often large nodules occur mostly as float, but can also be found in situ within the bituminous shale, colored purplish on the surface due to weathering

Size class: macrofossils

Preservation: mold/impression

Reposited in the NMMNH

• Repository: New Mexico Museum of Natural History and Science, Albuquerque, New Mexico, USA (NMMNH), Paleontological Institute and Museum, University of Zurich, Switzerland (PIMUZ)

Primary reference: C. Romano, A. López-Arbarello, D. Ware, J. F. Jenks, and W. Brinkmann. 2019. Marine Early Triassic Actinopterygii from the Candelaria Hills (Esmeralda County, Nevada, USA). Journal of Paleontology 93:971-1000 [M. Clapham/M. Clapham/M. Clapham]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 203221: authorized by Matthew Clapham, entered by Matthew Clapham on 06.08.2019

Creative Commons license: CC BY (attribution)

Taxonomic list

Osteichthyes
 Actinopterygii -
Actinopterygii indet. ray-finned fish
PIMUZ A/I 4727, 4728, 4731, 4732
 Parasemionotiformes - Parasemionotidae
Candelarialepis argentus n. gen. n. sp.
Candelarialepis argentus n. gen. n. sp. Romano et al. 2019 ray-finned fish
NMMNH P-57423
 Ptycholepiformes - Ptycholepididae
Ardoreosomus occidentalis n. gen. n. sp. Romano et al. 2019 ray-finned fish
NMMNH P-57422
 Palaeonisciformes - Rhadinichthyidae
Pteronisculus nevadanus n. sp. Romano et al. 2019
PIMUZ A/I 4402