The origin of modern marlins (Teleostei: Istiophoridae): new fossil evidence from the Lower Miocene of Austria

We report the oldest fossil record of Istiophoridae from the Northern Alpine Foreland Basin (Western Paratethys) in Pucking, Austria (Lower Miocene, lower Aquitanian, ∼22.4 Ma). The studied specimen consists of fragments of five articulated vertebrae and a partially preserved second dorsal fin. We found that the Pucking specimen is only surpassed in age by an isolated vertebra from the Chandler Bridge Formation (South Carolina, U.S.A.), with ∼24.7–23.5 Ma. Pucking and the Chandler Bridge Formation differ in age by ∼1.1–2.6 Ma. The fossil istiophorid from the Chandler Bridge Formation was considered controversial due to the large gap in the fossil record between the first appearance of Istiophoridae and the last appearance of any other extinct billfish clade. Here we report that Pucking (Lower Miocene) and South Carolina (Oligocene) share the occurrence of Istiophoridae, †Xiphiorhynchinae (Xiphiidae), and †Aglyptorhynchinae (†Palaeorhynchidae). Our finding demonstrates that the coexistence of different groups of billfishes is maintained over time and that the Chandler Bridge specimen is a reliable record. Our work closes a temporal gap of ∼4.4 Ma between the previously recognized oldest Istiophoridae (∼18 Ma) and the last appearance of †Xiphiorhynchinae and †Aglyptorhynchinae. This result supports a longer evolutionary history for Istiophoridae, establishes continuity in the billfish fossil record, and is significant for future time calibrated phylogenies.</p

An Upper Miocene marine turtle from panama that preserves osteocytes with potential DNA

Lepidochelys is a genus of extant marine turtles that includes the critically endangered Kemp's Ridley turtle. The evolutionary history of this genus is poorly understood due to the lack of an undisputed fossil record for the group. Here we describe a partially preserved carapace from the Upper Miocene Chagres Formation of Panama, which represents the oldest fossil record of Lepidochelys. The specimen has rectangular, anteroposteriorly short pleural scutes, a characteristic shared with members of Lepidochelys. It is potentially closely related to L. olivacea because it shares a similar number of pleurals, but its precise taxonomic status remains uncertain. We discuss the ecological role that a marine turtle played in the paleoecosystem of the Chagres Formation. The new specimen exhibits exceptional preservation of bone sutures, sulci, sculpturing, and bone microstructure, including remains of blood vessels, collagen fibers, and osteocytes. This is the first time that a histochemical stain (DAPI) indicates preservation of a compound consistent with DNA in a fossil vertebrate outside Dinosauria. These data demonstrate the potential for DNA to persist in specimens that are both millions of years old and are from lower latitudes, which challenges traditional paradigms of biomolecular preservation.</p

Evolutionary Patterns among Living and Fossil Kogiid Sperm Whales: Evidence from the Neogene of Central America

<div><p>Kogiids are known by two living species, the pygmy and dwarf sperm whale (<i>Kogia breviceps</i> and <i>K</i>. <i>sima</i>). Both are relatively rare, and as their names suggest, they are closely related to the sperm whale, all being characterized by the presence of a spermaceti organ. However, this organ is much reduced in kogiids and may have become functionally different. Here we describe a fossil kogiid from the late Miocene of Panama and we explore the evolutionary history of the group with special attention to this evolutionary reduction. The fossil consists of cranial material from the late Tortonian (~7.5 Ma) Piña facies of the Chagres Formation in Panama. Detailed comparison with other fossil and extant kogiids and the results of a phylogenetic analysis place the Panamanian kogiid, herein named <i>Nanokogia isthmia</i> gen. et sp. nov., as a taxon most closely related to <i>Praekogia cedrosensis</i> from the Messinian (~6 Ma) of Baja California and to <i>Kogia</i> spp. Furthermore our results show that reduction of the spermaceti organ has occurred iteratively in kogiids, once in <i>Thalassocetus antwerpiensis</i> in the early-middle Miocene, and more recently in <i>Kogia</i> spp. Additionally, we estimate the divergence between extant species of <i>Kogia</i> at around the late Pliocene, later than previously predicted by molecular estimates. Finally, comparison of <i>Nanokogia</i> with the coeval <i>Scaphokogia cochlearis</i> from Peru shows that these two species display a greater morphological disparity between them than that observed between the extant members of the group. We hypothesize that this reflects differences in feeding ecologies of the two species, with <i>Nanokogia</i> being more similar to extant <i>Kogia</i>. <i>Nanokogia</i> shows that kogiids have been part of the Neotropical marine mammal communities at least since the late Miocene, and gives us insight into the evolutionary history and origins of one of the rarest groups of living whales.</p></div

Ventral view of holotype skull of <i>Nanokogia isthmia</i> gen. et sp. nov. (UF 280000).

<p>Abbreviations: an, antorbital notch; bo/bs, basioccipital/basisphenoid; boc, basioccipital crest; cb.e, cerebral endocast; eam, external auditory meatus; fg, frontal groove; in, internal nares; jn, jugular notch; la+j, lacrimal + jugal; ma, mandible; mx, maxilla; npp, notch for posterior process of tympanic; oc, occipital condyles; pl, palatine; prs, presphenoid; ptdl, dorsal lamina of pterygoid; ptha, pterygoid hamulus; ptml, medial lamina of pterygoid; ptsf, pterygoid sinus fossa; tsr, tympanosquamosal recess; vif, ventral infraorbital foramen; vo, vomer. Gray shaded areas indicate sediment; diagonal lines denote broken surfaces.</p

Ventral views of kogiid skulls.

<p><i>Aprixokogia kelloggi</i> (USNM 187015), 12A, <i>Scaphokogia cochlearis</i> (MNHN PPI 229), 12B, <i>Praekogia cedrosensis</i> (UCMP 315229), 12C, <i>Nanokogia isthmia</i> gen. et sp. nov. (UF 273554), 12D, and (UF 280000), 12E, <i>Kogia sima</i> (LACM 47142), 12F, and <i>K</i>. <i>breviceps</i> (LACM 95745), 12G. Each bone is color-coded for ease of comparison. Areas in white are reconstructed, light gray areas are covered with sediment; diagonal lines denote broken surfaces. Illustrations based on direct observations of the specimens listed.</p

Right lateral view of holotype skull of <i>Nanokogia isthmia</i> gen. et sp. nov. (UF 280000).

<p>Abbreviations: eo, exoccipital; fg, frontal groove; fr, frontal; la+j, lacrimal + jugal; ma, mandible; mx, maxilla; lmc, lateral maxillary crest; npp, notch for posterior process of tympanic; of, optic foramen; pa, parietal; pgp, postglenoid process; pmx, premaxilla; ptdl, dorsal lamina of pterygoid; ptha, pterygoid hamulus; ptml, medial lamina of pterygoid; ptn, pterygoid notch; ptsf, pterygoid sinus fossa; scb, supracranial basin; sfc, sagittal facial crest; sq, squamosal; tc, temporal crest; zp, zygomatic process. Gray shaded areas indicate sediment; diagonal lines denote broken surfaces.</p

Posterior views of holotype (UF 280000), 7A-B, and referred specimen (UF 273554), 7CD, skulls of <i>Nanokogia isthmia</i> gen. et sp. nov.

<p>Abbreviations: boc, basioccipital crest; eo, exoccipital; fm, foramen magnum; jn, jugular notch; oc, occipital condyles; so, supraoccipital; sop, supraorbital process of frontal; tc, temporal crest. Gray shaded areas indicate sediment; diagonal lines denote broken surfaces.</p

Dorsal, 4A-B, and ventral, 4C-D, views of referred specimen of <i>Nanokogia isthmia</i> gen. et sp. nov. (UF 273554).

<p>Abbreviations: amc, anterior meatal crest; as, alisphenoid; bo, basioccipital; boc, basioccipital crest; dif, dorsal infraorbital foramen; eam, external auditory meatus; en, external nares; fg, frontal groove; fo, foramen ovale; fp, falciform process of squamosal; fr, frontal; jf, jugular foramen; jn, jugular notch; la+j, lacrimal + jugal; lmc, lateral maxillary crest; mx, maxilla; oc, occipital condyles; pmx, premaxilla; pop, postorbital process; prp, preorbital process; prs, presphenoid; ptdl, dorsal lamina of pterygoid; ptml, medial lamina of pterygoid; ptsf, pterygoid sinus fossa; scb, supracranial basin; so, supraoccipital; sq, squamosal; tsr, tympanosquamosal recess; vif, ventral infraorbital foramen; vo, vomer. Gray shaded areas indicate sediment; diagonal lines denote broken surfaces.</p

Right lateral views of kogiid skulls.

<p><i>Aprixokogia kelloggi</i> (left side, reversed, USNM 187015), 13A, <i>Scaphokogia cochlearis</i> (MNHN PPI 229), 13B, <i>Praekogia cedrosensis</i> (UCMP 315229), 13C, <i>Nanokogia isthmia</i> gen. et sp. nov. (based on UF 280000 and 273554), 13D, <i>Kogia sima</i> (LACM 47142), 13E, and <i>K</i>. <i>breviceps</i> (LACM 95745), 13F. Each bone is color-coded for ease of comparison. Areas in white are reconstructed; diagonal lines denote broken surfaces. Illustrations based on direct observations of the specimens listed.</p

Left, 6A-B, and right, 6C-D, lateral views of referred specimen of <i>Nanokogia isthmia</i> gen. et sp. nov. (UF 273554).

<p>Abbreviations: boc, basioccipital crest; eam, external auditory meatus; eo, exoccipital; fr, frontal; lmc, lateral maxillary crest; mx, maxilla; npp, notch for posterior process of tympanic; oc, occipital condyle; of, optic foramen; pa, parietal; pmx, premaxilla; pop, postorbital process; prp, preorbital process; prs, presphenoid; ptdl, dorsal lamina of pterygoid; ptml, medial lamina of pterygoid; scb, supracranial basin; smc, supramastoid crest; sq, squamosal; tc, temporal crest; vo, vomer; zp, zygomatic process. Gray shaded areas indicate sediment; diagonal lines denote broken surfaces.</p