Kerin M. Claeson

First Mesozoic Record of the Stingray Myliobatis wurnoensis from Mali and a Phylogenetic Analysis of Myliobatidae Incorporating Dental Characters

New specimens, including the first record of lower dental plates, of the extinct myliobatid Myliubatis wurnoensis were recovered from the Maastrichtian (Late Cretaceous) of the Iullemmeden Basin, Mali, and are the oldest record of the taxon. We evaluated the phylogenetic position of this taxon with reference to other myliobatids (extinct and extant) using osteology and dentition. Our results indicate that Myliobatinae and Myliobatis are each paraphyletic, and that Aetobatus and Rhinoptera are monophyletic. We also found that taxa known only from the Cretaceous, Brachyrhizodus and Igdabatis, are highly nested within Myliobatidae. The phylogenetic position of these taxa unambiguously extends the origin of Myliobatidae and most of its representative taxa into the Mesozoic.

A Virtual Phytosaur Endocast and its Implications for Sensory System Evolution in Archosaurs

ABSTRACT Many recent studies have detailed the morphology of archosaurian endocrania. However, the outgroup to Archosauria, Phytosauria, has yet to be studied with modern techniques that would allow reconstruction of their internal anatomy. Pseudopalatus mccauleyi is a derived phytosaur from the Upper Triassic Chinle Formation, Arizona. A skull of P. mccauleyi, USNM 15839, was imaged using computed tomography in order to create the first high-quality, digitally reconstructed phytosaur endocast. Pseudopalatus mccauleyi exhibits overall endocast morphology that is similar to that of an extant crocodylian. These clades, phytosaurs and extant crocodylians, exhibit convergent Baupläne and similar inferred ecologies. A notable difference between the endocasts of the two clades is a considerable dural expansion in P. mccauleyi that denotes a large pineal body. This expansion, and the overall morphology of the endocast, is consistent with the historic endocranial reconstructions of the phytosaurs Pseudopalatus buceros, Smilosuchus gregorii, and Parasuchus hislopi. A comparison with phylogenetically diverse archosaurian endocasts reveals that endocast morphologies are highly conserved within Pseudosuchia, regardless of Bauplan or ecology. This conservatism is in contrast to the diversity of endocast morphology observed within Theropoda and Sauropodomorpha, or between members of those clades and Pseudosuchia. The most pronounced variability in pseudosuchian endocast morphology is a trend in size reduction of the pineal region, from a large basal condition to a reduced derived condition wherein the pineal region is indistinguishable from the rest of the endocast. A similar trend in pineal reduction is also seen in theropods and sauropods. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline/UJVP

The impacts of comparative anatomy of electric rays (Batoidea: Torpediniformes) on their systematic hypotheses

The Comparative anatomy of the 11 recognized genera within Torpediniformes is described, systematically categorized, and illustrated in a comprehensive photo‐atlas. Data are compiled into a character matrix and cladistically analyzed using parsimony to test hypotheses about the previously recognized subfamilies, while reconstructing the possible evolutionary history of Torpediniformes. Results are consistent with the previous rank‐based classifications, regardless of the parsimony criteria used to generate the phylogenetic hypothesis, with one notable exception: a monophyletic Narcininae was never recovered. Torpedinoidea (=Hypnos + Torpedo) is supported by the presence of long, slender, flexible jaw cartilages, absence of a large rostral fontanelle, presence of suprascapular antimeres that are each shorter than the scapular process of the scapulocoracoid, antorbital cartilages that articulate on the anterior aspect of the nasal capsules and absence of a frontoparietal fontanelle. Subfamilial names Hypninae and Torpedininae are redundant with the genus names Hypnos and Torpedo and are not adopted here. Narcinoidea (=nontorpedinoid torpediniforms) is supported by unambiguous character transformations to the presence of a divided lower lip, labial cartilages, laterolingually compressed palatoquadrates, bifurcated antorbital cartilages, a rostral fontanelle, ventrally projecting nasal capsules, a dorsal rim of the synarcual mouth posterior to occipital condyle, posteriorly positioned lateral stays, and obtuse anterior margins of lateral stays. Narkidae is supported by unambiguous character transformations to the presence of an uncovered eye that protrudes above dorsal surface, a shared rim between the spiracle and the eye, an anterior nasal turret that projects ventrally, a nasal curtain that covers the upper lip and dentition when the mouth is closed, tab‐like prepelvic processes, a mesopterygium that is shorter than propterygium but longer than metapterygium, a slender median rostral cartilage, and a basibranchial cartilage with an anterior margin that is depressed medially and a posterior margin that tapers. J. Morphol. 275:597–612, 2014.

A Revision of the Upper Cretaceous Lepidosirenid Lungfishes from the Quseir Formation, Western Desert, Central Egypt

ABSTRACT We evaluate new lungfish remains from the Upper Cretaceous Quseir Formation in the Western Dessert of southern Egypt. Taxa include Lavocatodus protopteroides, L. humei, L. giganteus, and Protopterus nigeriensis. We treat Lavocatodus as members of Lepidosirenidae based on the presence of a well-defined medial articular surface, in the absence of a symphyseal surface of corresponding prearticular bones. Material of L. protopteroides represents the first example of an adult specimen, supporting the retention of the species as valid, and not a junior synonym of L. humei. Specimens of L. humei are the most abundant in the assemblage, and all exhibit the medial articular surface, a feature that is absent from specimens of Ceratodus; therefore, we reassign additional specimens of ‘C.’ humei to Lavocatodus. New specimens of L. giganteus extend the temporal and spatial ranges of the species (the type material of L. giganteus is from Paleocene deposits of In Farghas, Mali). Finally, a new specimen of Protopterus represents the oldest record of the genus in Egypt. The prearticular is confidently assigned to Protopterus based on the presence of only three ridges on the tooth plate, a medial symphyseal suture, a coronoid process, and a shallow tooth crown plus prearticular depth. We further assign it to P. nigeriensis based the length and merger of tooth ridges. Furthermore, the oldest Cenomanian specimens reported from the Sudan Wadi Milk Formation are assigned to P. nigeriensis, which would extend the temporal range of P. nigeriensis by roughly 14 Ma.

Alestid (Characiformes: Alestidae) fishes from the late Oligocene Nsungwe Formation, Rukwa Rift Basin, of Tanzania

ABSTRACT Alestidae is a clade of African characiform fishes including 19 extant genera and approximately 105 species that are known from Afro-Arabia, with records reported from the Eocene-Oligocene Jebel Qatrani Formation of Egypt, the Eocene Mahenge crater lake of Tanzania, and early Oligocene to Miocene sites on the Arabian Plate. Here we report the first record of alestid fishes from the late Oligocene Nsungwe Formation in the Rukwa Rift Basin of southwestern Tanzania. The Nsungwe alestid sample is composed of 92 teeth spanning a range of sizes and morphologies. Teeth are examined with regard to cusp number and organization, tooth position and replacement, and in the context of alestid jaw organization using modern, comparative representatives. Results suggest that at least two alestid taxa are represented in Nsungwe Formation localities. Hydrocynus teeth exhibit a single, conical cusp. Several of these specimens preserve a mesiodistally expanded crown and concave surface on the lingual aspect of the tooth. A second, unnamed taxon, with three morphological variants, is distinguished from Hydrocynus based on a multicuspid morphology of fully erupted teeth. The presence of these taxa in the late Oligocene of Africa below the equator provides key insights into the biogeography of the clade.

A synoptic review of the Eocene (Ypresian) cartilaginous fishes (Chondrichthyes: Holocephali, Elasmobranchii) of the Bolca Konservat-Lagerstätte, Italy

Here, we review and discuss the records and taxonomy of the Ypresian (Eocene) chondrichthyans from the famous Bolca Konservat-Lagerstätte in northeastern Italy. Despite the outstanding diversity and the numerous studies focusing on the actinopterygian faunas from Pesciara and Monte Postale, the current knowledge about the systematics, taxonomy and phylogenetic relationships of the cartilaginous fishes from these Eocene sites remains elusive and largely inadequate. The celebrated Eocene Bolca Lagerstätte has yielded several exquisitely preserved articulated remains of chondrichthyan fishes in which delicate structures and soft tissues are preserved, as well as isolated teeth. The cartilaginous fish assemblage of Bolca comprises at least 17 species-level taxa belonging to 10 families in 6 orders, including selachians (Carcharhiniformes, Lamniformes), batoids (Torpediniformes, Myliobatiformes, Rajiformes) and holocephalans (Chimaeriformes). The occurrence of holocephalans represented by an isolated fin-spine of the chimeroid Ischyodus in the Bolca assemblage is reported here for the first time and represents the first record of chimeroids in the Eocene of Italy and also southern Europe. The Bolca chondrichthyan assemblage is remarkably different from those of other contemporaneous Boreal or Tethyan deposits, suggesting that its taxonomic composition is largely influenced by the palaeoenvironmental context. However, this synoptic review also highlights the importance of detailed revisions of all chondrichthyan remains from the Bolca Konservat-Lagerstätten.KurzfassungObwohl Knochenfische in der berühmten eozänen (Ypresium) Bolca-Konservatlagerstätte in NE-Italien äußerst divers sind und in den vergangenen Jahren Gegenstand zahlreicher Studien waren, ist der derzeitige Kenntnisstand über die Systematik, Taxonomie und Phylogenie der Knorpelfische aus dieser Lagerstätte überraschend gering und ungenau. In dieser Studie geben wir einen Überblick über die Knorpelfische der Bolca-Konservatlagerstätte und diskutieren ihre Verbreitung und ihre Taxonomie. Aus den beiden Fundstellen Pesciara und Monte Postale stammen einige sehr gut erhaltene Exemplare, bei denen auch sehr feine Strukturen und Weichgewebe fossilisiert sind, sowie isolierte Zähne. Die Knorpelfischfauna von Bolca umfasst mindestens 17 Arten, die zu zehn Familien und sechs Ordnungen gehören wie Haie (Carcharhiniformes, Lamniformes), Rochen (Torpediniformes, Myliobatiformes, Rajiformes) und Chimären. Chimären sind erstmals für Bolca durch einen isolierten Flossenstachel von Ischyodus belegt, was gleichzeitig der erste Nachweis für Chimären im Eozän von Italien und Süd-Europa ist. Die Knorpelfischassoziation von Bolca unterscheidet sich in ihrer taxonomischen Zusammensetzung auffällig von anderen tethyalen und auch borealen Faunen. Dies lässt vermuten, dass die taxonomische Zusammensetzung im Wesentlichen durch Umweltbedingungen bestimmt ist. Der hier präsentierte synoptische Überblick der Bolca-Knorpelfische zeigt aber auch deutlich, dass detaillierte Revisionen aller Knorpelfischreste der Bolca-Konservatlagerstätte für ein besseres Verständnis dieser wichtigen eozänen Fundstelle dringend nötig sind.

Revision of Eocene electric rays (Torpediniformes, Batomorphii) from the Bolca Konservat-Lagerstätte, Italy, reveals the first fossil embryo in situ in marine batoids and provides new insights into the origin of trophic novelties in coral reef fishes

The Eocene electric ray †Titanonarke Carvalho, 2010 from the Bolca Konservat-Lagerstätte, north-eastern Italy, is redescribed in detail based upon new material from recent excavations. This taxon exhibits a combination of features (large voids between the pectoral and the axial skeleton filled in life by electric organs, anteriorly directed fan-shaped antorbital cartilages, lack of dermal denticles, long prepelvic processes, and rounded basibranchial copula with a small caudal tab) that clearly supports its assignment to the order Torpediniformes. The analysis of new material also demonstrates that the previous apparent absence of typical narcinoid characters used to diagnose †Titanonarke was the result of taphonomic biases. †Titanonarke shares at least three synapomorphies (presence of a rostral fontanelle, low number of ribs, and rostral cartilage connected to the antorbital cartilage through lateral appendices) with the extant genera Benthobatis, Diplobatis, Discopyge and Narcine, with which it forms a clade (family Narcinidae) recognized herein as unquestionably monophyletic. Moreover, based upon a single specimen of †Titanonarke that exhibits a unique combination of morphometric and meristic features, a new species of Eocene numbfish, †T. megapterygia sp. nov., is recognized. The presence of several specimens representing different ontogenetic stages of at least two species of numbfishes suggests a close association of this taxon with shallow-water habitats corresponding to coral reefs as hypothesized for the Monte Postale palaeoenvironment. The occurrence of a fossilized marine batoid embryo is reported here for the first time. Moreover, the analysis of the gut contents suggests that the dietary adaptations of †Titanonarke can be related, at least in part, to an opportunistic strategy in the context of abundant larger foraminifera in the Monte Postale palaeobiotope, suggesting that this kind of feeding mode, known to occur in present-day reefs, already was realized 50 million years ago. http://zoobank.org/urn:lsid:zoobank.org:pub:EDD6E170-CA64-4FFB-8DD1-AED2D61D5504

A New Genus and Species of Marine Catfishes (Siluriformes; Ariidae) From the Upper Eocene Birket Qarun Formation, Wadi El-Hitan, Egypt

Wadi El-Hitan, the UNESCO World Heritage Site, of the Fayum Depression in the northeast part of the Western Desert of Egypt, has produced a remarkable collection of Eocene vertebrates, in particular the fossil whales from which it derives its name. Here we describe a new genus and species of marine catfishes (Siluriformes; Ariidae), Qarmoutus hitanensis, from the base of the upper Eocene Birket Qarun Formation, based on a partial neurocranium including the complete left side, partial right dentary, left suspensorium, two opercles, left pectoral girdle and spine, nuchal plates, first and second dorsal spines, Weberian apparatus and a disassociated series of abdominal vertebrae. All of the elements belong to the same individual and some of them were found articulated. Qarmoutus gen. nov. is the oldest and the most complete of the Paleogene marine catfishes unearthed from the Birket Qarun Formation. The new genus exhibits distinctive features not seen in other African Paleogene taxa, such as different sculpturing on the opercle and pectoral girdle with respect to that on the neurocranium and nuchal plates, denticulate ornamentation on the skull bones arranged in longitudinal rows and forming a radiating pattern on the sphenotic, pterotic, extrascapular and the parieto-supraoccipital, indentations or pitted ornamentation on the nuchal plates as well as the parieto-supraoccipital process, strut-like radiating pattern of ornamentation on the opercle from the proximal articulation to margins, longitudinal, curved, reticulate ridges and tubercular ornamentations on the cleithrum, sinuous articulation between the parieto-supraoccipital process and the anterior nuchal plate, long, narrow, and arrowhead shaped nuchal shield, very small otic capsules restricted to the prootic. Multiple parsimony and Bayesian morphological phylogenetic analyses of Ariidae, run with and without “molecular scaffolds”, yield contradictory results for the placement of Qarmoutus; the genus is either a phylogenetically basal ariid, or it is deeply nested within the ariid clade containing New World species of Sciades.

New fossil scombrid (Pelagia: Scombridae) fishes preserved as predator and prey from the Eocene of Senegal

ABSTRACT. Lower Eocene fossil fish material from the Thies Formation in the region of Bargny near the Cap-Vert peninsula, Senegal, reveals predator-prey interaction between two scombrid fishes, the first ever described in the fossil record for the clade. The material is a part and counterpart concretion preserving nearly complete skulls of both predator and prey in 3-dimensions. The larger, predator-fish is here proposed as the second specimen of †Auxides huberti, the only non-Tethyan representative of †Auxides. The smaller, prey-fish is a new genus and species, †Eoscomber senegalicus, closely resembling Scomber. Evidence that †E. senegalicus gen. et sp. nov. was swallowed includes the presence of several of its caudal vertebrae obscured near the area of the opercle of †A. huberti and continuing into its pharynx. Additionally, the skull of †E. senegalicus. is partially enclosed within the abdominal ribs of †A. huberti. †Auxides huberti is the only species of †Auxides recovered with serrated pelvic fin spines, which are normally smooth. †Auxides huberti has 28–30 vertebral centra (16–17 caudal) including the urostyle. The new specimen of †A. huberti has small, pointed teeth and a thickened, sickle-shaped first haemal spine. The first dorsal fin has 6–7 interneurals and associated dorsal fin spines. The bony dorsal and anal finlets begin immediately behind the second dorsal and anal fins respectively. Ventral corselet-like scales are present, a condition similar to that of the genera Auxis, and Thunnus, but unlike the type species of †Auxides. The caudal fin has gracile hemitrichia that proximally surround the entire hypural plate and the two posteriormost epineurals. †Eoscomber senegalicus. differs from Scomber in possessing frontal bones that approach the midline anteriorly and long sigmoid shaped nasal bones that project further anteriorly past the frontal bone than the length of the nasalarticulating surface. The exceptional preservation of †E. senegalicus and the second ever recorded occurrence of †A. huberti, is the first direct evidence of scombrid feeding behavior and demonstrates that smaller ‘mackerel-like’ scombrids have been prey for larger tuna-like scombrids since at least the middle Eocene as they are today.