A new antiarch (placoderm fish) from the Early Devonian of South China
Titel:
A new antiarch (placoderm fish) from the Early Devonian of South China
Auteur:
Guorui, Zhang Young, G. C.
Verschenen in:
Alcheringa
Paginering:
Jaargang 16 (1992) nr. 3 pagina's 219-240
Jaar:
1992
Inhoud:
A new bothriolepidoid antiarch of small size, Luquanolepis pileos gen. et sp. nov. is described from the Early Devonian of Luquan County, Yunnan Province. Only remains of the trunk armour are known. It is characterised by the long dorsal wall, with a strong posterior process formed by the posterior median dorsal and posterior dorsolateral plates, the posterior median dorsal longer and broader than the anterior median dorsal, a strongly developed posterior internal tranverse crista anteriorly placed at about the middle of the length of the dorsal trunk armour, and an independent posterior lateral plate. It is one of the few antiarchs known from the Early Devonian which has a developed brachial process and segmented pectoral fin. The small unpaired semilunar plate, subanal lamina and other features indicate bothriolepid affinities, and the separate posterior lateral suggests it is a stem taxon within the bothriolepidoids, a group to which 13 genera are assigned. Distribution of 19 characters amongst these taxa is summarised in a data matrix used in a computer-assisted cladistic analysis of the group to produce over 100 equally parsimonious trees. By eliminating poorly known taxa and characters from the analysis and inferring some missing character states 14 equally parsimonious trees were produced for 10 bothriolepidoid taxa. Luquanolepis is regarded as the most primitive member within the clade, consistent with the fact that it is the oldest bothriolepidoid genus so far discovered.
Tijdschrift beschrijving