Pelagornithidae Research Articles

Bone microstructure of bony-toothed birds (Odontopterygiformes) from the Eocene of Ikove, Ukraine: preliminary paleobiological implications

ABSTRACT Histological structure of long bones from bony-toothed birds (Odontopterygiformes) from Early Lutetian locality Ikove (Ukraine) is examined for the first time. Six limb bones from Pelagornithidae cf. Dasornis sp. and Lutetodontopteryx tethyensis are described. The bones, although usually being fragmented, show good preservation at the microscopic level. Their microstructure (e.g. orientation and diameter of primary osteons) significantly varies, but the basic pattern and, therefore, the way of growth matches that of recent Neognathae (as well as a number of extinct taxa). In young birds, the periosteum quickly deposited well-vascularised primary bone, which at the same time was resorbed from inside, then the animal reached adult size and fast bone growth gave way to much slower deposition of circumferential layers of lamellar or parallel-fibred tissue on the outer and inner bone surfaces. The bones also underwent Haversian remodelling of various extent (from nearly absent to nearly full), generally stronger in larger bones and in the inner compacta. Bone microstructure is consistent with high metabolic rates, expected in Odontopterygiformes, and implies that their growth rates were comparable to those of recent Neognathae.

Partial skeleton from the Paleocene of New Zealand illuminates the early evolutionary history of the Phaethontiformes (tropicbirds)

We describe a new stem group representative of the Phaethontiformes (tropicbirds) from the Paleocene Waipara Greensand in New Zealand. The fossil consists of a partial skeleton with a nearly complete skull and represents the first unambiguous record of the Phaethontiformes from the Paleocene of the Southern Hemisphere. Clymenoptilon novaezealandicum gen. et sp. nov. has a proportionally shorter pelvis than Prophaethon shrubsolei from the early Eocene London Clay and appears to have been less adapted to foraging in an aquatic environment at or below sea-level. It is furthermore distinguished from P. shrubsolei and Lithoptila abdounensis from the late Paleocene/early Eocene of Morocco in a proportionally smaller foramen magnum of the skull. Together with other plesiomorphic features, this suggests that C. novaezealandicum is the sister taxon of a clade including Lithoptila, Prophaethon and crown group Phaethontiformes, and as one of the oldest stem group phaethontiforms the new species may indicate a Southern Hemispheric centre of origin of tropicbirds. After a recently described bony-toothed bird, C. novaezealandicum is the second seabird species from the Waipara Greensand to show affinities to taxa from the early Paleogene of the Northern Hemisphere. The wide early Paleogene distribution of the Phaethontiformes stands in sharp contrast to the geographic restriction of coeval diving seabirds, and different factors appear to have limited the dispersal of aquatic and pelagic seabird taxa in the early Paleogene. Gerald Mayr [Gerald.Mayr@senckenberg.de], Senckenberg Research Institute and Natural History Museum Frankfurt, Ornithological Section, Senckenberganlage 25, D-60325 Frankfurt am Main, Germany; Vanesa L. De Pietri [vanesa.depietri@canterbury.ac.nz], University of Canterbury, School of Earth and Environment, Private Bag 4800, Christchurch 8140, New Zealand; Al Mannering [alman@slingshot.co.nz], Canterbury Museum, Rolleston Avenue, Christchurch 8050, New Zealand; Leigh Love [lvlove@xtra.co.nz], PO Box 49, Waipara 7483, New Zealand; Erica Crouch [e.crouch@gns.cri.nz], GNS Science, 1 Fairway Drive, Lower Hutt 5040, New Zealand; Catherine Reid [catherine.reid@canterbury.ac.nz], University of Canterbury, School of Earth and Environment, Private Bag 4800, Christchurch 8140, New Zealand; R. Paul Scofield [pscofield@canterburymuseum.com], Canterbury Museum, Rolleston Avenue, Christchurch 8050, New Zealand, and University of Canterbury, School of Earth and Environment, Private Bag 4800, Christchurch 8140, New Zealand.

Growth duration, life history and ecological traits of bony-toothed birds (Odontopterygiformes): implications from bone histology

Bony-toothed birds (Odontopterygiformes), an order of seabirds that existed throughout most of the Cenozoic, had unusually fragile, thin-walled bones. This complicates their study and draws attention to microscopic methods, which are applicable even to fragmentary remains. The histological structure of long bones of the limbs of two species from the lower Lutetian locality Ikove (Luhansk Oblast, Ukraine) was studied: Lutetodontopteryx tethyensis and cf. Dasornis sp., representing the two main clades of the order. The well-preserved microstructure of the bones sheds light on the growth pattern of these birds, which turned out to be similar to that of recent Neognathae: with rapid and typically sharply terminated bone growth. This resulted in the apposition of azonal woven-parallel tissue, covered with outer and inner circumferential layers (OCL and ICL), usually sharply delimited from it. Like in other birds, osteohistological features allow to distinguish gross developmental stages of the animals (juveniles, young adults, and older adults) and provide hints about events of their life history, such as egg-laying or moulting, which enhance the development of resorption cavities and, probably, secondary osteons. The humeri of L. tethyensis show a structure of the outer cortex unusual for birds, which indicates a less abrupt than usual growth cessation. Age determination from the sub-layers in the inner circumferential layer (a method which works in some species of recent birds but not in other) proved impossible for L. tethyensis; for cf. Dasornis sp. the question remains open. The duration of the growth in the studied species cannot currently be determined precisely, but can be estimated at 102 days, probably (in contrast to previous inferences) less than one year. A relatively short development supports the hypothesis about Odontopterygiformes being specialised consumers of squid, based on the morphology of the pseudoteeth. Eating squid can be an explanation of the observed osteohistological features, which could be caused by calcium deficiency.

Earliest fossils of giant-sized bony-toothed birds (Aves: Pelagornithidae) from the Eocene of Seymour Island, Antarctica

While pelagornithid or ‘bony-toothed’ bird fossils representing multiple species are known from Antarctica, a new dentary fragment of a pelagornithid bird from the middle Eocene Submeseta Formation on Seymour Island, Antarctica represents a species with a body size on par with the largest known species in the clade. Measurements from the partial ‘toothed’ dentary point to a giant body size for the species, although the spacing among the pseudoteeth differs from that published for other pelagornithids. The discrepancy might suggest that previous techniques are not adequate for examination of incomplete material or that another factor such as phylogeny might impact size estimates and comparisons. Combined with a revised stratigraphic position in the early Eocene La Meseta Formation on Seymour Island for the largest pelagornithid tarsometatarsus known, these Antarctic fossils demonstrate the early evolution of giant body size in the clade (by ~ 50 Ma), and they likely represent not only the largest flying birds of the Eocene but also some of the largest volant birds that ever lived (with an estimated 5–6 m wingspan). Furthermore, the distribution of giant-sized pelagornithid fossils across more than 10 million years of Antarctic geological deposits points to a prolonged survival of giant-sized pelagornithids within the southern seas, and their success as a pelagic predatory component of marine and coastal ecosystems alongside early penguins.

The earliest record (early Miocene) of a bony-toothed bird from South America and a reexamination of Venezuelan pelagornithids

ABSTRACTPelagornithids or bony-toothed birds were an enigmatic group of very large marine birds that existed throughout most of the Tertiary, with remains recovered in all continents. The currently recognized record of pelagornithids in South America extends from the middle Miocene to the Pliocene. Here, a fragment of a ramus mandibulae recently discovered in the Cerro La Cruz site (Castillo Formation, Lara State, northwestern Venezuela), is assigned to Pelagornis. With an early Miocene age (18.27–18.85 Ma), the fossil constitutes the earliest unequivocal record of the group in South America. The reexamination of another pelagornithid specimen recovered from Capadare Formation (middle Miocene), which was previously assigned to Pelagornithidae indeterminate, allows us to recognize the presence during the Miocene of Venezuela of a second pelagornithid morphotype, here tentatively referred to Pelagornis chilensis Mayr and Rubilar-Rogers, 2010. Originally recorded from the middle Miocene-early Pliocene of Chile, the possible presence of P. cf. P. chilensis during the middle Miocene of Venezuela might represent the first record of this bony-toothed species outside Chile and expands its distribution area by 3500 km, to the tropical waters of northern South America. Citation for this article: Solorzano, A., and A. D. Rincon. 2015. The earliest record (early Miocene) of a bony-toothed bird from South America and a reexamination of Venezuelan pelagornithids. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2014.995188.

Partial skeleton of a bony-toothed bird from the late Oligocene/early Miocene of Oregon (USA) and the systematics of Neogene Pelagornithidae

A partial skeleton of a pelagornithid bird found in latest Oligocene or earliest Miocene marine strata in Oregon consists of a pelvis fragment, thoracic vertebrae, and leg bones of a single individual. It is the most completely preserved pelagornithid from the late Oligocene/early Miocene, and one of the few bony-toothed birds from this time period in general. The new fossil is from the Nye Mudstone and shows some previously unknown features that contribute to a better understanding of the osteology of pelagornithids. Because Paleogene and late Neogene pelagornithids differ in several osteological features and the temporally intermediate forms are poorly known, it further bridges a gap in our knowledge of character evolution in pelagornithids. The interrelationships within Pelagornithidae are still poorly resolved, but we detail that a clade of Neogene species, which the Oregon pelagornithid is not part of, can be supported by a derived morphology of the femur. To ease description of Neogene pelagornithids, we synonymize Palaeochenoides Shufeldt, 1916 and Tympanonesiotes Hopson, 1964 with Pelagornis Lartet, 1857, and suggest classification of all Neogene pelagornithids in the latter taxon.

A new genus and species of Pelagornithidae with well-preserved pseudodentition and further avian remains from the middle Eocene of the Ukraine

ABSTRACT We describe new avian remains from the middle Eocene of eastern Ukraine. The material includes well-preserved bones of a small species of Pelagornithidae (bony-toothed birds), which was tentatively identified as Odontopteryx toliapica in an earlier study. The Ukrainian pelagornithid is, however, distinguished from this species and other early Eocene pelagornithids in several features, and we describe it as Lutetodontopteryx tethyensis, gen. et sp. nov. The new material includes the most complete pseudodentition of a small Paleogene pelagornithid, and details of pseudotooth morphology strengthen previous assumptions that the pseudodentition of pelagornithids derives from tooth-specific developmental programs and is homologous to true avian teeth on a molecular level. Most major postcranial bones of L. tethyensis are represented by well-preserved bones, and in some derived morphological features the Ukrainian species agrees with Neogene pelagornithids but differs from the early Eocene Dasornis species. We also report a partial sternum of a much larger bony-toothed bird, which resembles the sternum of the middle Eocene Gigantornis eaglesomei. We further describe previously unknown skeletal elements of the loon Colymbiculus udovichenkoi (Gaviiformes), which show that this species substantially differs, in both wing and leg morphology, from the well-known gaviiform stem-group taxon Colymboides.

First giant bony-toothed bird (Pelagornithidae) from Australia

The Pelagornithidae, or ‘giant bony-toothed birds,’ are enigmatic extinct seabirds with a long history spanning the late Paleocene–late Pliocene (Harrison, 1985; Mourer-Chauvire and Geraads, 2008, ...

Middle Eocene Pelagornithidae and Gaviiformes (Aves) from the Ukrainian Paratethys

Abstract: We describe avian remains from Novopskov, a new middle Eocene marine locality in Ukraine. The fossils constitute the most substantial collection of Palaeogene bird bones from Eastern Europe and contribute to a better knowledge of the Paratethyan seabird fauna. Most of the specimens belong to Pelagornithidae (bony-toothed birds), and two species of very different size can be distinguished. The larger of these is tentatively referred to Dasornis sp., the smaller to Odontopteryx toliapica. The specimens include skeletal elements that were not described for Palaeogene bony-toothed birds and document previously unknown morphological differences between Palaeogene and Neogene Pelagornithidae. It is argued that the purported crane Eobalearica tugarinovi, from the middle Eocene of Kyrgyzstan, is probably also a bony-toothed bird. A new genus and species of small Gaviiformes, Colymbiculus udovinchenkoi, is described, which is the earliest fossil record of a loon from Europe, preceding the next oldest specimens by more than 10 myr. The Ukrainian fossils document profound differences between middle Eocene and extant marine avifaunas of Europe, and whereas the middle Eocene Paratethyan avifauna appears to have been similar to that of the North Sea with regard to pelagornithid diversity, the absence of prophaethontids and relative abundance of Gaviiformes may indicate faunistic differences concerning the remaining seabirds.

Cenozoic mystery birds – on the phylogenetic affinities of bony‐toothed birds (Pelagornithidae)

Mayr, G. (2011) Cenozoic mystery birds – on the phylogenetic affinities of bony‐toothed birds (Pelagornithidae). —Zoologica Scripta, 40, 448–467.The extinct Cenozoic bony‐toothed birds (Pelagornithidae) are characterized by the occurrence of unique spiky projections of the osseous jaws and are among the most distinctive neornithine taxa. Earlier authors considered these marine birds to be most closely related to ‘Pelecaniformes’ or Procellariiformes, but recent phylogenetic analyses resulted in a sister group relationship to Anseriformes. This latter hypothesis was, however, coupled with a non‐monophyly of galloanserine or even neognathous birds, which is not supported by all other current analyses. The character evidence for anseriform affinities of pelagornithids is thus reassessed, and it is detailed that the alleged apomorphies cannot be upheld. Pelagornithids lack some key apomorphies of galloanserine birds, and analysis of 107 anatomical characters did not support anseriform affinities, but resulted in a sister group relationship between Pelagornithidae and Galloanseres. By retaining a monophyletic Galloanseres, this result is in better accordance with widely acknowledged hypotheses on the higher‐level phylogeny of birds. The (Pelagornithidae + Galloanseres) clade received, however, only weak bootstrap support, and some characters, such as the presence of an open frontoparietal suture, may even support a position of Pelagornithidae outside crown‐group Neognathae.

Latest Pacific Basin record of a bony-toothed bird (aves, Pelagornithidae) from the Pliocene Purisima Formation of California, U.S.A.

ABSTRACT Fossils of pelagornithids (bony-toothed birds) have been reported from strata of Paleocene to Pliocene age, and from every continent. The extreme fragility of pelagornithid bones has no doubt contributed to their geographically and temporally sporadic record, and thus it has been difficult to appreciate any long-term phylogenetic trends through geologic time for this group. We report a well-preserved partial humerus of the gigantic bird Pelagornis from the late Neogene Purisima Formation of central California. Due to its incompleteness, we refrain from naming a new species. This fossil is fortuitously bracketed by two ash beds, which have been correlated with volcanic rocks at 3.35 ± 0.05 Ma and 2.5 ± 0.2 Ma, indicating a middle to late Pliocene age for this fossil. This fossil extends the record of the pelagornithids in the Northeast Pacific, previously only known up until the early late Miocene (10–12 Ma). This fossil is the latest record of a pelagornithid for the Pacific Basin, and additionally represents the latest reliably dated pelagornithid record worldwide. This record suggests that the pelagornithids survived until the end of the Pliocene, and became extinct during the ocean restructuring and climatic upheavals that caused the demise of many other groups of marine vertebrates at that time.

Osteology of a new giant bony-toothed bird from the Miocene of Chile, with a revision of the taxonomy of Neogene Pelagornithidae

ABSTRACT Bony-toothed birds (Pelagornithidae) were among the largest volant birds, but their representatives from the upper size range have so far been known only from very fragmentary fossils. Here we report an exceptionally well-preserved giant species from the late Miocene of the Bahía Inglesa Formation in northern Chile, in which most major limb bones are complete and uncrushed. The fossil has the longest wing skeleton of any bird, and its wingspan in life was at least 5.2 m. Mass estimates of 16–29 kg are, however, surprisingly low and within the range of large extant volant birds, or only moderately above. The fossil constitutes the most substantial record of the Pelagornithidae (bony-toothed birds), and is assigned to a new species, Pelagornis chilensis. It is one of the largest known pelagornithids and the three-dimensionally preserved bones allow recognition of many previously unknown osteological features, especially concerning the vertebrae, pectoral girdle, and limb elements. We revise the taxonomy of Neogene pelagornithids and propose classification of all Miocene and Pliocene species into a single genus, Pelagornis. Osteological features are highlighted in which giant Neogene Pelagornithidae differ from their smaller Palaeogene relatives.

A sternum of a very large bony-toothed bird (Pelagornithidae) from the Miocene of Portugal

ABSTRACT The sternum of a very large bony-toothed bird (Pelagornithidae) from the Miocene of Portugal is described. The three-dimensionally preserved specimen is one of the largest sterna of a volant bird known to date, and more complete than the only other pelagornithid sternum reported so far. It is tentatively assigned to Pelagornis miocaenus Lartet, 1857, which is the only bony-toothed bird known from the Miocene of Europe. The specimen shows several unique features, including the presence of a marked cranial projection of the carina sterni, which probably abutted the extremitas sternalis of the furcula, and a large, steep-walled opening in the cranial portion of the facies visceralis. The corpus sterni further has a highly unusual shape in that it is very deep, with a strongly vaulted facies visceralis. It is likely that these characteristics are due to anatomical constraints imposed by the very large size of pelagornithids, which may have reached a wingspan of up to 6 m and probably were incapable of sustained flapping flight.

A pseudodontorn (Pelecaniformes: Pelagornithidae) from the middle Pliocene of Hawera, Taranaki, New Zealand

Abstract The distal portion of a right humerus and the proximal end of a radius, belonging to a ‘bony-toothed bird’ (family Pelagornithidae), were collected from marine sediments at Hawera, North Island, New Zealand, and are of Waipipian age (middle Pliocene). This is the first record of a pseudodontorn from the North Island, the third for New Zealand. These specimens extend the world geological time range for this family of extinct birds (previously early Eocene to late Miocene) into the middle Pliocene.

Bone of a presumed odontopterygian bird from the Miocene of New Zealand

Abstract A partial right humerus of a bird of probable Waiauan (middle to late Miocene) age, from the coastal cliffs of North Canterbury, and tentatively considered to belong to the order Pelicaniformes: sub-order Odontopterygia (bony-toothed birds) is described.