Taxonomic revision ofPlesiofuro mingshuicafrom the Lower Triassic of northern Gansu, China, and the relationships of early neopterygian clades

Abstract

The ray-finned fish Plesiofuro mingshuica from the Triassic non-marine deposits of northern Gansu Province, China, was previously misidentified as a caturid halecomorph. This erroneous taxonomic assignment contributed to the misinterpretation of the age of the Plesiofuro-bearing fossil beds as Early Jurassic. Here, we provide a taxonomic revision of this problematic taxon based on a comparative study including over 500 new specimens. The revised description of Plesiofuro accommodates significant changes to the reconstruction of the snout, skull roof, cheek, circumorbital, and operculogular series, as well as the lower jaw. Results of a cladistic analysis incorporating these new data place Plesiofuro as a stem-group neopterygian. Additionally, phylogenetic results show that both 'Perleidiformes' and 'Peltopleuriformes' are paraphyletic, encompassing several independent stem-neopterygian subclades. As such, this study sheds new light on one of the least resolved areas of osteichthyan phylogeny: the so-called 'subholosteans' of the neopterygian total group.

A new species ofPlatysiagumfrom the Luoping Biota (Anisian, Middle Triassic, Yunnan, South China) reveals the relationship between Platysiagidae and Neopterygii

“…The basal position of Platysiagidae (as well as that of Perleidiformes) within Neopterygii found here is in good agreement with the results of Xu et al (2015), Xu & Ma (2016), and Xu & Zhao (2016).…”

“…All characters were treated as unordered and equally weighted. Characters were coded mainly based on Xu et al (2015) and published data, together with codings of Platysiagum minus based on Brough (1939), Bürgin (1992Bürgin ( , 1996 and specimens in the Natural History Museum, London (holotype NHMUK P.19408 and paratype NHMUK P.19420 of Platysiagum minus), Helmolepis based on Mutter (2005), Neuman & Mutter (2005), and Altisolepis based on Mutter & Herzog (2004), Sun et al (2015) and our new specimens.…”

“…The phylogenetic position of the new species was cladistically tested mainly based on an analysis of the data matrix created by Xu et al (2015). We made six changes.…”

Evolution of caudal fin ray development and caudal fin hypural diastema complex in spotted gar, teleosts, and other neopterygian fishes

“…10A–C in Ebert et al, ). Many other basal neopterygian lineages, however, cannot be studied due to the covering of the caudal peduncle and caudal fin by scales (e.g., in Lombardo, ; Lin et al, ; Sun et al, ; Xu et al, ) limiting considerably the inference of presence of a hypural diastema in basal neopterygians.…”

A Middle Triassic thoracopterid from China highlights the evolutionary origin of overwater gliding in early ray-finned fishes

“…Viviparity occurs in 14 families of living teleosts and two coelacanth species, which together account for only 2-3% of species of extant bony fishes [13]. The Triassic Peltopleuriformes (probably paraphyletic [14]) have independently evolved the viviparity because they show hooklets in the supposed male anal fin [15,16]. These hooklets might have played an important role in sperm transfer to females; a study of the living viviparous guppy (Poecilia) showed that up to threefold more sperm were transferred when males had hooklets compared with those with hooklets removed [17].…”