Articles | Volume 20, issue 1
Research article
31 Jan 2017
Research article |  | 31 Jan 2017

The lower actinopterygian fauna from the Lower Carboniferous Albert shale formation of New Brunswick, Canada – a review of previously described taxa and a description of a new genus and species

Kathryn E. Mickle

Abstract. The Lower Carboniferous Albert shale formation of New Brunswick, Canada, is well-known for the preservation of countless articulated lower actinopterygian palaeoniscoid fishes. This site is at the boundary between the Devonian and the Lower Carboniferous, making the lower actinopterygians preserved at this site important. The taxonomic history of previously described Albert shale formation actinopterygians is reviewed here. Many of the earliest described actinopterygian taxa from the Albert Formation are represented by poorly preserved type specimens and have the distinction of being moved from one paraphyletic genus to another paraphyletic genus. While these taxa are in need of major redescriptions, such work is premature until the large paraphyletic or polyphyletic genera they have been placed in, Palaeonicus[m], Rhadinichthys, and Elonichthys, are redescribed. But there is new diversity within the Albert shale formation. Here, a new lower actinopterygian species, Lambeia pectinatus, is described from one well-preserved specimen. This new species is characterized by dorsal ridge scales with pectinated posterior margins, body scales inserted between adjacent dorsal ridge scales, body scales with pectinated posterior and ventral margins, the presence of a ventral rostro-premaxilla and a median rostral bone, a separate and distinct antorbital bone, and a single supraorbital bone. This newly described species is distinct from previously described fishes from the Albert Formation, and the morphology of this newly described species is more similar to later Carboniferous fishes rather than Devonian fishes. This suggests that morphological features commonly seen in Carboniferous fishes and rarely seen in Devonian fishes were present early in the Carboniferous.

Short summary
A new lower actinopterygian fossil fish genus and species is described from a Paleozoic site in Canada. The new taxon, based on the study of a well-preserved fossil, is defined by a unique combination of characters including features of the scales and the bones of the snout. A review of previously described fishes from this locality highlights how redescriptions of large cosmopolitan genera, and descriptions of new taxa, are vital to our understanding of the diversity of this group as a whole.