†Xiphiorhynchoides haeringensis, a new genus and species of Billfish – Paleontology of the Oligocene Ashley and Chandler Bridge Formations of South Carolina

FIERSTINE, Harry L. & Friedrich H. PFEIL:
†Xiphiorhynchoides haeringensis, a new genus and species of Billfish (Perciformes: Xiphioidei: Xiphiidae: †Xiphiorhynchinae) from Bad Häring, Tyrol, Austria, Lower Oligocene (NP 22)

The skull and anterior body of a large billfish related to the genus †Xiphiorhynchus was collected in the deep-water, near-shore marine Paisslberg Formation, Lower Oligocene (NP 22) at Bad Häring, Tyrol, Austria. It is the most complete specimen known of the subfamily †Xiphiorhynchinae. Its rostrum has many features of †Xiphiorhynchus: composed of paired premaxillae that fuse together distally, an internal canal system with a central canal and two pairs of lateral canals, and a ventral surface covered with villiform teeth. It has the following features previously unknown in †Xiphiorhynchus: lower jaw that is as long the upper and with a fused symphysis, large hyoid apparatus, complete suspensorium, pectoral fins and girdles, dorsal and anal fins, up to eleven articulating vertebrae. We were unable to locate pelvic fins, maxillae, nasals, prenasals, or scales.
The neurocranium is unlike others identified as †Xiphiorhynchus with its elongate ethmoid and apparent lack of nasals. In addition, all elements in its pectoral girdle are aligned in the dorso-ventral plane. The Bad Häring specimen differs enough from †Xiphiorhynchus that we identify it as a new genus and species, †Xiphiorhynchoides haeringensis.

FIERSTINE, Harry L. & Robert E. WEEMS:
Paleontology of the Oligocene Ashley and Chandler Bridge Formations of South Carolina, 4: Analysis and New Records of Billfishes (Perciformes: Xiphioidei)

The billfish fauna of the Ashley and Chandler Bridge formations consists of three species of †Aglyptorhynchus [†A. robustus (LEIDY, 1860), †A. palmeri n. sp., and †A. alsandersi n. sp.] and one species of †Xiphiorhynchus [†X. rotundus (WOODWARD, 1901), plus numerous specimens identifiable either to †Aglyptorhynchus sp., †Xiphiorhynchus sp., or Istiophoridae genus and species indeterminate. Numerous morphological features are described for the first time, including the maxilla and opisthocelous first vertebra of †A. robustus, the anterior neurocranium and suspensorium of †A. palmeri, and a series of middle precaudal and posterior caudal vertebrae identified as †Aglyptorhynchus sp. Based on the ball and socket articulation of the first vertebra and occipital condyle, and the probable articulation of the maxilla to the neurocranium and angulo-articular, it is postulated that †Aglyptorhynchus had a mobile rostrum to increase its gape and a mobile head that may have been useful in prey capture. The middle precaudals have elongated and flattened neural spines, but they are very thin and probably did little to stiffen the vertebral column. The caudal fin skeleton is composed of three vertebrae (preurals 2 and 3, and hypural) with the preural 2 having a deep groove for articulation with a stout hemal spine. The hypural is a single fused structure with a well-developed hypurapophysis and deep grooves for overlapping caudal fin rays.
†Aglyptorhynchus is assigned to the Family †Palaeorhynchidae BLAINVILLE, 1818, partly because it shares with †Palaeorhynchus BLAINVILLE, 1818, the unusual feature of a downturned flange on the maxilla. Because detailed morphology of most individual bones of †Palaeorhynchus is unknown, †Aglyptorhynchus is separated from †Palaeorhynchus in the new subfamily †Aglyptorhynchinae.
The remains of †Xiphiorhynchus in the Ashley and Chandler Bridge formations demonstrate that the genus was probably represented by more than one species in the late Oligocene of North America, that additional specimens of †X. rotundus were present and the length of some vertebrae indicate xiphiorhynchins grew to a large size that rivals or exceeds the largest recorded size of the extant swordfish (Xiphias LINNAEUS, 1758). The presence of an istiophorid in an Oligocene deposit is noteworthy because no other specimen that has been unequivocally identified as an istiophorid has ever been found in a deposit older than middle Miocene.
No differences were observed between the billfish fauna of the Ashley and Chandler Bridge formations, in spite of the fact that the former is considered to be about 2 Ma older and was deposited in a middle-outer continental shelf environment, whereas the Chandler Bridge Formation was deposited in a nearshore, possibly lagoonal setting. The presence of †Aglyptorhynchus and †Xiphiorhynchus on both sides of the Atlantic Ocean and in the Tethys Seaway supports the hypothesis that a single North Atlantic-Tethys biogeographic province may have existed during the early Tertiary.