First fossil insect record from the Arroyo Totoral Formation (Lower Permian), Paganzo Basin, La Rioja Province, Argentina
The Permian entomofaunas (~290–252 Ma) were characterized by many Carboniferous groups, but they also marked the origin of new insect orders such as the basal relatives of plecopterans, mecopterans, psocopterans, and beetles. During this time, new mouthpart types (e.g., stylate piercing-and-sucking)...
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| Autores principales: | , , , , , |
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| Formato: | Reunión |
| Lenguaje: | Inglés |
| Publicado: |
Asociación Paleontológica Argentina
2025
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| Materias: | |
| Acceso en línea: | http://repositorio.unne.edu.ar/handle/123456789/59285 |
| Aporte de: |
| Sumario: | The Permian entomofaunas (~290–252 Ma) were characterized by many Carboniferous groups, but
they also marked the origin of new insect orders such as the basal relatives of plecopterans,
mecopterans, psocopterans, and beetles. During this time, new mouthpart types (e.g., stylate
piercing-and-sucking) and functional feeding activities appeared, hence the seeking of new food
sources, which led to the diversification, evolution, and expansion of the herbivorous insects. More
than 35 fossil insect species, represented by forewing impressions, have been collected and
described from different Permian outcrops of Argentina, Brazil, and Uruguay. In Argentina, the insect
records come from the Bajo de Véliz (Paganzo Basin, San Luis Province) and Río Genoa (Tepuel Genoa
Basin, Chubut Province) formations. The fossils include both terrestrial phytophagous and
detritivores insects such as palaeodictyopteroids (e.g., megasecopterans Sphecorydaloididae,
Diaphanopteridae, Breyeriidae), polyneopteran "protorthopterans" (Proedischiidae) groups, and
"cockroachoids" (Phyloblattidae). Here, we present the first fossil insect from the Arroyo Totoral
Formation (early Lower Permian), south of Sierra de Los Llanos, in the eastern sector of the Paganzo
Basin, southeastern La Rioja Province, Argentina. The specimen consists of a compression of a single
right forewing, collected by "Macuca Team" during fieldwork carried out in 2022/2023 in Arroyo
Totoral outcrops, and is housed at the Colección de Paleoinvertebrados, Centro Regional de
Investigaciones Científicas y Transferencia Tecnológica de la Rioja (CRILAR-CONICET), under the CRIPI
acronym. The fossil is associated to a diverse paleoflora including glossopterids, pteridosperms,
conifers, cordaitaleans, ferns, and sphenophytes, which developed under local humid conditions for
the Sierra de Los Llanos area during Permian times. Based on the general venation scheme that
include an elongated and comparatively narrow costal field, widened areas between the main veins
(e.g., Sc, R), Sc pectinated, with branches mostly simple and nearly straight; this new specimen can be
tentatively attributed to the predominantly Paleozoic Family Phyloblattidae (stem-Dictyoptera). This
finding represents the first known early Permian insect found for both the La Rioja Province and
Arroyo Totoral Formation pointing the unit as a new promising site for the search of fossil insects in
Argentina. Future paleontological prospections in this formation will undoubtedly enrich our
understanding on the diversity of insects during their early evolution. |
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