Brachiopods, crustaceans, vertebrates, and charophytes from the Devonian Ly Hoa, Nam Can and Dong Tho formations of Central Vietnam

Patrick RACHEBOEUF, Phuong TA HOA, Hung NGUYEN HUU, Monique FEIST & Philippe JANVIER

en Geodiversitas 28 (1) - Pages 5-36

Published on 31 March 2006

New vertebrate remains are described from the Ly Hoa Formation (Quang Binh Province, Central Vietnam). They provide further information about the morphology and phylogenetic position of the antiarch Vukhuclepis lyhoaensis within the Yunnanolepididae, the first evidence for a Petalichthyida, a suborbital plate tentatively referred to a Holonematidae, and evidence that a third arthrodire (in addition to the former and Lyhoalepis duckhoai), possibly a brachythoracid, is present in this fauna. Some new sarcopterygian remains referred to a Youngolepididae are also described. Some fragments are referred, with reservations, to a galeaspid. Associated fragments referred to an undetermined phyllocarid crustacean, as well as an undetermined arthropod are described, in association with this vertebrate fauna. The presence of Yunnanolepididae, Youngolepididae, and possibly galeaspids clearly confirms the South Chinese affinity of the Ly Hoa vertebrate fauna. Its age remains debated, but its composition is rather suggestive of a late Early Devonian, probably Emsian, age. A new Chonetidina, Corbicularia noongdensis n. sp., is described from the brachiopod fauna of the Nam Can Formation (Nghe An Province, Central Vietnam) and suggests a Givetian-Frasnian age for this formation. A new Chonetidina, ?Holynetes caurongensis n. sp., as well as ?Dagnachonetes sp. are described from the Dong Tho Formation (Quang Binh Province, Central Vietnam), and also suggest a Frasnian age for the middle part of this formation. The basal part of the Dong Tho Formation has yielded remains of an antiarch referred to Bothriolepis sp., as well as utricles of Charophytes referred to Sycidium haikouense, a species known elsewhere in the Givetian of China.


Vertebrata, Crustacea (Phyllocarida), Brachiopoda (Chonetidina), Charophyta, Devonian, Central Vietnam, biostratigraphy, palaeobiogeography

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