A Middle-Late Devonian fish fauna from the Sierra de Perijá, western Venezuela, South America
A new Devonian fossil fish fauna from the region of Caño Colorado between the Rio Palmar and Rio Socuy, Sierra de Perijá, Venezuela, comes from two localities and several horizons within the Campo Chico Formation, dated on plants and spores as Givetian-Frasnian in age. Placoderms are most common, wi...
| Published in: | Fossil Record |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Pensoft Publishers
2002
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| Subjects: | |
| Online Access: | https://doi.org/10.1002/mmng.20020050111 https://doaj.org/article/429f26efd67948dc8eada5ba6487cb47 |
| Summary: | A new Devonian fossil fish fauna from the region of Caño Colorado between the Rio Palmar and Rio Socuy, Sierra de Perijá, Venezuela, comes from two localities and several horizons within the Campo Chico Formation, dated on plants and spores as Givetian-Frasnian in age. Placoderms are most common, with the antiarch Bothriolepis perija n. sp., showing affinity with species from the Aztec fish fauna of Victoria Land, Antarctica. A second antiarch, Venezuelepis mingui n.g. n.sp., is also closely related to an Antarctic species, which is reassigned to this new genus. Fragmentary remains of a phyllolepid placoderm show similarity to the genus Austrophyllolepis from southeastern Australia. Chondrichthyan spines are provisionally referred to the Antarctilamnidae, and acanthodian remains include spines of the widespread taxon Machaeracanthus. Osteichthyans are represented by osteolepid and dipnoan scales and teeth, and scales lacking cosmine which may belong to another major taxon. This fauna has provided the first Devonian record from South America of three major fish groups: antiarch and phyllolepid placoderms, and dipnoans. These are widely distributed on most other continents. Although invertebrates and plants from the same sequence closely resemble those of eastern North America, the endemic elements in the fish fauna indicate Gondwana affinities. Phyllolepid placoderms are common in Givetian-Frasnian strata of Australia and Antarctica, but are only known from the Famennian in the Northern Hemisphere. The new phyllolepid occurrence extends their range across the northern margin of Palaeozoic Gondwana. The age and affinities of this new fish fauna are consistent with a model of biotic dispersal between Gondwana and Euramerica at or near the Frasnian-Famennian boundary. A narrow marine barrier separating northern and southern continental landmasses is indicated, in contrast to the wide equatorial ocean for the Late Devonian postulated from palaeomagnetic data.Es wird eine neue devonische Fischfauna aus dem Gebiet ... |
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