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Our understanding of early gnathostome evolution has been hampered by a generally scant fossil record beyond the Devonian. Recent discoveries from the late Silurian Xiaoxiang Fauna of Yunnan, China, have yielded significant new information, including the earliest articulated osteichthyan fossils from the Ludlow-aged Kuanti Formation. Here we describe the partial postcranium of a new primitive bony fish from the Kuanti Formation that represents the second known taxon of pre-Devonian osteichthyan revealing articulated remains. The new form, Sparalepis tingi gen. et sp. nov., displays similarities with Guiyu and Psarolepis, including a spine-bearing pectoral girdle and a placoderm-like dermal pelvic girdle, a structure only recently identified in early osteichthyans. The squamation with particularly thick rhombic scales shares an overall morphological similarity to that of Psarolepis. However, the anterior flank scales of Sparalepis possess an unusual interlocking system of ventral bulges embraced by dorsal concavities on the outer surfaces. A phylogenetic analysis resolves Sparalepis within a previously recovered cluster of stem-sarcopterygians including Guiyu, Psarolepis and Achoania. The high diversity of osteichthyans from the Ludlow of Yunnan strongly contrasts with other Silurian vertebrate assemblages, suggesting that the South China block may have been an early center of diversification for early gnathostomes, well before the advent of the Devonian “Age of Fishes”. [ABSTRACT FROM AUTHOR]

Moythomasiais one of the most speciose and completely known of all Devonian actinopterygian genera and has been incorporated into numerous phylogenetic studies. However, several species remain incompletely documented despite being known from excellent fossil material. Specimens from the Late Devonian of Germany and Australia are described herein. A form from Bergisch Gladbach, Germany, previously described by Jessen asMoythomasiacf.striata, is recognized as a new species:M. lineata, sp. nov. Newly prepared specimens ofMoythomasia durgaringafrom the Gogo Formation, Western Australia, allow for the first rigorous full-body reconstructions of this species. Aspects of the dermal skeleton and body shape of this form are updated over previous descriptions. The genus is currently problematic owing to the highly fragmentary nature of the type species,M. perforatafrom Kokenhusen; however, it is considered provisionally valid owing to distinctive cranial ornamentation. The three completely known species (M. durgaringa, M. nitda, andM. lineata, sp. nov.) do not share any unique squamation-based characters exclusive to other Devonian actinopterygians, invalidating purely scaled-based referrals to this genus. http://zoobank.org/urn:lsid:zoobank.org:pub:E7048A6B-852C-4331-8613-32DCB7E27DA2 [ABSTRACT FROM PUBLISHER]