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

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

A new lower actinopterygian fish from the Upper Mississippian Bluefield Formation of West Virginia, USA

The Upper Mississippian Bluefield Formation of the Mauch Chunk Group in southeastern West Virginia is known for its preservation of a variety of invertebrate taxa and early tetrapod trackways, but no lower actinopterygian remains have been formally described from these Carboniferous rocks. Here, the first lower actinopterygian fish is described from the Bluefield Formation of West Virginia. This fish is represented by a nearly complete articulated specimen with a three-dimensional snout and an unobstructed view of the gular and branchiostegal region. This new taxon is defined by a unique set of characters, which include features of the snout, circumorbital series, cheek, and operculo-gular region. These features make this fish different and distinct from previously described Carboniferous fishes. Some of the morphological features of note include the presence of a distinct lacrimal, premaxillary, ventral rostral and dorsal rostral bones, a narrow infraorbital ventral to the orbit, and a large crescent shaped infraorbital that contacts a single dermosphenotic. There is an anteriorly inclined hatchet-shaped preoperculum and six small suborbital bones anterior to the expanded region of this bone that filling the space between the preoperculum, dermosphenotic, and infraorbital. Posterior to the preoperculum, there is a single wedge-shaped dermohyal and a series of three rectangular anteopercular bones. The anteopercular bones extend halfway down the anterior border of the rectangular operculum. A median gular, two pairs of lateral gulars, and at least eight branchiostegal rays are present. The heterocercal caudal fin is deeply cleft and inequilobate. The scales have pectinated posterior margins and bear diagonal ridges of ganoine. The description of this new taxon represents the first actinopterygian and the first vertebrate body fossil described from the Bluefield Formation and the second actinopterygian taxon described from the Mauch Chunk Group in West Virginia

Unraveling the Systematics of Palaeoniscoid Fishes--Lower Actinopterygians in Need of a Complete Phylogenetic Revision

Actinopterygian fishes are the most diverse and speciose vertebrates on the planet. Lower actinopterygians, or fishes basal to teleosts, are critical to our understanding of the early evolution of this group, but extant lower actinopterygians are only represented by a few species. A larger diversity is preserved in the fossil record, but these fishes are poorly understood. This dissertation focuses on a subset of the extinct diversity; palaeoniscoid actinopterygians. The term "palaeoniscoid" has been used to refer to a large paraphyletic grouping of fossil fishes ranging from the Devonian to the Cretaceous. Our poor understanding of the diversity and relationships of palaeoniscoids reflects the many taxa of palaeoniscoids that remain to be described and included in phylogenetic analyses, as well as our understanding of morphological characters amongst lower actinopterygians. The main goal of this dissertation is to dismantle the paraphyletic grouping of palaeoniscoid fishes by concentrating on reassessments of morphological characters, descriptions of new taxa, and phylogenetic analyses of a vast number of taxa from the Devonian to the recent using both parsimony and Bayesian methodologies. Chapter One gives a taxonomic review of lower actinopterygians and discusses obstacles that must be overcome in order to form stronger hypotheses of relationships for palaeoniscoids. These obstacles are then addressed in the subsequent chapters. Chapters Two and Three are investigations into morphological characters. Chapter Two examines the preoperculum, a cheek bone considered important in the evolution of actinopterygians. Chapter Three presents problems with how the bones in the snout of lower actinopterygian fishes have been identified and proposes a new identification and nomenclature scheme for the bones of the snout. Chapters Four and Five are descriptions of new taxa from the Carboniferous of Utah and New Brunswick, Canada. Lastly, Chapter 6 presents results of phylogenetic analyses of lower actinopterygians. The data matrix analyzed incorporates the findings from the previous chapters with the addition of new characters, character states, and taxa. This matrix represents the largest analysis to date of lower actinopterygian fishes, and the first time Bayesian methodology is used to investigate the relationships of palaeoniscoid fishes. Results of both methodologies are compared to each other and previously published hypotheses. Most importantly, analysis of this matrix has resulted in the recovery of a monophyletic Paleonisciformes. The results of this chapter suggest that palaeoniscoid actinopterygians represent a natural grouping

Zooplankton Biodiversity Patterns Across a Novel Water Storage Complex in the NJ Pinelands

The study involves the collection of zooplankton samples from Whitesbog, which is an inactive cranberry bog complex that is used as water storage for cranberry harvest during the fall season. Whitesbog is novel because very little human activity occurs in the surrounding area that could degrade water quality, but the complex itself is not natural. The water found in the upstream parts of the bog is highly acidic, which likely creates a gradient of ecological dystrophy in the zooplankton community. In this study, we investigate patterns of density and biodiversity across the complex and question whether these patterns are driven by physical-chemical conditions. Zooplankton density for different species varies between sites, with some sites changing more than others over time. Water temperature was the best predictor of zooplankton density, but it is unclear with present data whether this is a non-linear or linear response gradient. Turbidity and water temperature are the best predictors of zooplankton biodiversity, but the environmental variables we measured were insufficient to explain much of the observed differences between sites. Further testing is needed