New Mexico Geological Society Annual Spring Meeting — Abstracts

The Kinney Brick Quarry Lagerstätte (KBQL) in the Manzanita Mountains of central New Mexico is a world-famous locality for Late Pennsylvanian fossil plants, invertebrates and vertebrates in the Missourian Tinajas Member of the Atrasado Formation.The KBQL is a classic Konservat Lagerstätte, which preserves soft tissues and other delicate structures. It yields palynomorphs, a diverse, conifer-rich megaflora, a shelly marine invertebrate assemblage that includes a few cephalopods, the very common brackish pectinacean bivalve Dunbarella, lingulid and other brachiopods, and several syncarid and hoplocarid crustaceans, ostracods, conchostracans, eurypterids, and terrestrial arthropods, mostly insects and rare diplopods, a diverse assemblage of fishes, mostly acanthodians and palaeoniscoids, some marine sharks and rare branchiosaurid amphibians, as well as coprolites and “fish eggs.” The depositional setting of the KBQL is an estuary fed by a river delta that was filled by continental fluvial clastics. A renewed interest in large-scale collecting at the KBQL adds several new specimens to the record of terrestrial and aquatic arthropod fossils from the site. Arthropod groups previously represented at the KBQL include myriapods (centipedes and millipedes), insects (blattoids and a possible brodiid), chelicerates (eurypterids and a trigonotarbid) and crustaceans (branchiopods, ostracods and syncarids). Here we round out the five major arthropod groups (myriapods, insects, chelicerates crustaceans and trilobites) by adding the pygidium of a trilobite, Ditomopyge cf. D. scitula (NMMNH [NM Museum of Natural History] P-69194), to the KBQL record. This specimen closely resembles Ditomopyge scitula specimens found at Cedro Canyon and Jemez Springs, NM. Additional arthropod specimens include several blattoids and crustaceans, two myriapods, two eurypterids, a palaeodictyopterid and an exceptionally well preserved mesothele spider, which is the oldest known. The spider (NMMNH P-71523) is the first from the Atrasado Formation of New Mexico and is an important addition to the sparse global fossil record of early aranids. The insect fauna of the KBQL is important in two relationships. First, the co-occurrence of the cockroachoid spiloblattinid insect-zone species together with marine zone fossils, e.g., conodonts, in the KBQL enabled the direct link of nonmarine cockroachoid-bearing deposits, which are widespread in Late Paleozoic Euramerica, to the global marine scale.Second, the KBQL assemblage preserves a coastal insect fauna. As is typical of the Late Pennsylvanian and Early Permian, it is dominated by cockroachoids. However, the entomofauna of the KBQL seems to be much more diverse than those of the contemporaneous inland faunas far from the sea. This compares well to the highly diverse nearshore marine insect localities of the Namurian from Ningxia in China and Hagen-Vorhalle in Germany as well as to the Early Permian coastal plain locality, Carrizo Arroyo, in New Mexico. The addition of so many new terrestrial and aquatic arthropod specimens to the KBQL record suggests that biodiversity was much higher than formerly thought. This supports the idea that nearshore environments such as the KBQL may be not only evolutionary hot spots for the earliest terrestrialisation of arthropods during the Early Paleozoic but for the later diversification of insects, too.