A new species of long‐snouted lungfish from the Late Devonian of Australia, and its functional and biogeographical implications

Abstract

A new species of the Late Devonian lungfish Rhinodipterus is described from the Frasnian Gogo Formation, northern Western Australia. The description is based on a single specimen preserved in a small concretion, represented by elements of the skull roof, lower jaw, palate, neurocranium, hyoid arch, pectoral girdle and other parts of the postcranial skeleton. Rhinodipterus kimberleyensis sp. nov. differs from other species in the shape of its parasphenoid, number of tooth rows, nature of the tooth plates and characteristics of the skull roof. Functional morphology suggests Rhinodipterus kimberleyensis sp. nov. had a weak bite and may have fed off the reef substrate. Rhinodipterus kimberleyensis sp. nov. possessed a suite of skeletal characters that suggest it may have breathed air. Morphological comparison and a cladistic analysis place Rhinodipterus crown-ward of all other Gogo lungfishes and closely related to Oervigia, Andreyevichthys and Orlovichthys. Faunal comparisons between Australia and Laurussia indicate palaeobiogeographical links existed between these landmasses during the Middle to Late Devonian.

The cranial endocast of the Middle Devonian dipnoan Dipterus valenciennesi and a fossilized dipnoan otoconial mass

“…) either exclusively used dentition (Campbell and Barwick ), incorporated characters from the rest of the body or included non‐Devonian taxa. The efficacy of the neurocranial matrix of Friedman () has led subsequent authors to use it in more recent studies of new Devonian taxa (Qiao and Zhu ; Clement ) and also for post‐Devonian taxa (Pardo et al . ) as an alternative means to support phylogenetic hypotheses derived from characters throughout the entire body.…”

“…Bayesian analysis was conducted in MrBayes v.3.2.0 using the same procedure as Friedman (). Two data sets were used, that of Friedman () and Clement (), both with missing data for D. valenciennesi amended (see Challands ). The matrix of Pardo et al .…”

“…The matrix of Pardo et al . () has not been used in this study as it is identical to that of Clement () but includes the Permian form Persephonichthys cthonica .…”

“…However, the state of dipnoan endocast research is not yet in a position to assess with confidence which cranial endocast characters may be phylogenetically informative. As such, characters from the endocast have not been incorporated into phylogenetic analyses, and recently published Devonian dipnoan phylogenies (Clement ; Pardo et al . ) still exhibit a large polytomy comprising Sorbitorhynchus deleaskitus , Pillararhynchus longi , Melanognathus canadensis , Chirodipterus liangchengi and, the main subject of this study, Dipterus valenciennesi .…”

An Exceptionally Preserved Transitional Lungfish from the Lower Permian of Nebraska, USA, and the Origin of Modern Lungfishes

“…We additionally coded the new taxon into the braincase-only matrix of Friedman [13] as modified by Clement [20] (Appendix S2) to test whether the relationships of Persephonichthys chthonica within Devonian lungfishes remained robust to removal of homoplastic skull roof characters. For the neurocranium-only analysis, 70 neurocranial characters were coded for 28 taxa.…”