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Home , Odontopteryx, Osteodontornis, Pelagornis, Pelagornithidae, Teratornithidae

Flight performance of the largest volant

Daniel T. Ksepkaa,b,1,2

aNational Evolutionary Synthesis Center, Durham, NC 27705; and bDepartment of Marine, Earth and Atmospheric Sciences, State University, Raleigh, NC 27695

Edited* by Paul E. Olsen, Columbia University, Palisades, NY, and approved June 13, 2014 (received for review November 14, 2013) is an extinct of characterized by bizarre based on combinations of viable mass estimates, aspect ratios, and -like bony projections of the jaws. Here, the flight capabil- wingspansasdescribedinMethods. ities of pelagornithids are explored based on data from a with the largest reported among birds. sand- Systematic ersi sp. nov. is represented by a and substantial postcranial Aves Linnaeus, 1758. Pelagornithidae Fürbringer, 1888. Pela- material. Conservative wingspan estimates (∼6.4 m) exceed theo- gornis Lartet, 1857. P. sandersi sp. nov. retical maximums based on extant soaring birds. Modeled flight properties indicate that lift:drag ratios and glide ratios for P. sand- . Charleston Museum (ChM) PV4768, cranium and right ersi were near the upper limit observed in extant birds and sug- mandibular ramus, partial , right scapula, right gest that pelagornithids were highly efficient gliders, exploiting lacking distal end, proximal and distal ends of the right , frag- a long-range soaring . ments of and , right , , fibula, tarsometatarsus, and single pedal phalanx (Fig. 1). Aves | | | paleontology | pseudotooth Etymology. sandersi honors retired Charleston Museum curator light ability in birds is largely governed by scaling effects, Albert Sanders, collector of the holotype. leading to a tradeoff between the benefits of physiological F Locality and Age. The holotype was collected from Bed 2 of the efficiencies and the drawbacks of decreasing power margin (ratio Chandler Bridge Formation (22) near Charleston Airport

of available muscle power to required mechanical power) as size (Charleston, SC). It is late Oligocene (lower , ~25–28 Ma) increases (1–4). Over their ∼150-My history, birds evolved to in age based on calcareous nannoplankton biostratigraphy (23). span at least four orders of magnitude in size (2) and achieve a wide variety of flight styles, such a flap-gliding, soaring, and Diagnosis. P. sandersi exhibits diagnostic characteristics of Pela- hovering. Today, the largest directly measured wild individuals of gornis (10), including rostrum with transverse furrow, tricipital volant birds reach of ∼3.5 m (Royal Dio- ∼ fossa situated on the ventral surface of humerus, and tibiotarsus medea exulans) and masses of 19 kg (Great Otis tarda with medial markedly more anteriorly projected than and Kori Bustard Ardeotis kori) (5). In the past, the extinct ter- lateral condyle. P. sandersi can be differentiated from other restrial teratorn magnificens (6) and the extinct soar- species of Pelagornis by the slender caudal portion of the man-

ing Pelagornithidae (7–10) greatly exceeded these sizes. Given EARTH, ATMOSPHERIC,

dible [deep and squared in Pelagornis chilensis and Pelagornis AND PLANETARY SCIENCES the challenges of flight at large size, there has been much debate (Pseudodontornis) longirostris], the more elongate , a larger over potential upper size limits for different styles of flight in number of mandibular pseudoteeth (31 vs. 20 in P. chilensis), and – vertebrates (1, 2, 11 13), and the evolution of specialized taxa, larger size. P. sandersi can further be differentiated from Pela- like teratorns and pelagornithids, has been tied to environmental gornis () orri by the presence of two (vs. six) small – factors, such as wind patterns (6, 14 16). intervening pseudoteeth between the first two large pseudoteeth A well-preserved associated representing the largest in the rostral portion of the upper jaw. It can be differentiated known volant bird provides the basis for the present study of from Pelagornis mauretanicus by the larger size of the caudalmost flight properties in the remarkable extinct clade Pelagorni- set of mandibular pseudoteeth, Pelagornis stirtoni by the markedly thidae. Pelagornithidae appeared in the (9) and attained a global distribution before going extinct in the Significance (8, 17). Skeletal characteristics, including pseudoteeth (spike-like protrusions of the jaw ), a hinged , and specialized wing bones (7–10, 18, 19), have raised questions about the paleo- A fossil species of pelagornithid bird exhibits the largest ecology and phylogenetic affinities of Pelagornithidae. Although known avian wingspan. Pelagornithids are an extinct group of Pelagornithidae has historically been linked to the birds known for bony tooth-like beak projections, large size, and highly modified wing bones that raise many questions and (7, 8, 20), more recent phylogenetic analyses about their ecology. At 6.4 m, the wingspan of this species was suggest that this extinct clade is the sister to approximately two times that of the living Royal Albatross. (waterfowl) (9) or Galloanserae (waterfowl and landfowl) (21). Modeling of flight parameters in this species indicates that it Regardless of their affinities, Pelagornithidae evolved such was capable of highly efficient gliding and suggests that highly modified skeletal morphologies that it would not be pelagornithids exploited a long-range marine soaring strategy plausible to make meaningful inferences about their flight style and similar, in some ways, to that of extant . ecology based on extant relatives. Therefore, computer modeling

provides the best path toward understanding the flight capabilities Author contributions: D.T.K. designed research, performed research, analyzed data, and of these remarkable birds. Flight 1.25 (2), a program designed to wrote the paper. model avian flight under user-specified conditions, is ideally Conflict of interest statement: Editor P.E.O. served as a committee member for the dis- suited to this task, because it models both flapping and gliding sertation of D.T.K. in 2007. flight performance. In this study, Flight 1.25 is applied to infer *This Direct Submission article had a prearranged editor. flight parameters in the largest known pelagornithid species. As 1Present address: Science Department, Bruce Museum, Greenwich, CT 06830. with all research on fossil organisms, estimating variables, such as 2Email: [email protected]. mass and length, requires additional extrapolation, and This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10. these uncertainties are taken into account with 24 iterative analyses 1073/pnas.1320297111/-/DCSupplemental.

www.pnas.org/cgi/doi/10.1073/pnas.1320297111 PNAS Early Edition | 1of6 Downloaded by guest on September 26, 2021 Fig. 1. (Upper) Reconstruction of P. sandersi (elements preserved in the holotype are shown in white) with D. exulans (Royal Albatross; 3-m average wingspan) for scale. (Lower) P. sandersi holotype (ChM PV4768) skull in (a) dorsal, (b) ventral, (c) left lateral (mandible in medial view), and (d) right lateral views (mandible in lateral view). Right humerus in (e) caudal and (f) cranial views. Scapula in (g) lateral and (h) medial views. (i) Partial furcula femur in (j) cranial and (k) caudal views. Tibiotarsus in (l) cranial and (m) caudal views. Fibula in (n) lateral view. Tarsometatarsus in (o) dorsal view (distal portion exposed in the medial view because of deformation) and (p) rotated to show the distal portion in dorsal view. (q) Pedal phalanx. cc, Lateral cnemial crest; fac, fossa aditus canalis neurovascularis; fc, facet; haf, humeral articular facet; ie, intercotylar eminence; j, jugal; lf, lateral furrow; mtII, metatarsal trochlea II; nfh, nasofrontal hinge; pf, pneumatic foramen; pp, paroccipital process; sf, subcondylar fossa; sup, supra-angulare; sw, swelling on crista deltopectoralis; syn, synovial ; tb, tubercle; trf, transverse furrow.

more robust femur, and Pelagornis (Paleochenoides) mioceanus by for the tip of the sternal keel. The gently sigmoid humerus is marked lack of a deep sulcus on the fibular trochlea of the femur. SI by a massive protuberance on the cranial face (17). The distally dis- Appendix has additional comparisons. placed deltopectoral crest bears a centrally located swelling. The fe- mur has a deep intercondylar sulcus but lacks a well-defined sulcus on Description. Two low ridges separated by a midline depression the fibular trochlea. The cnemial crests of the tibiotarsus are short, mark the skull roof, which has been partially flattened by dor- and the shaft is sigmoidally curved. The tarsometatarsus shows a soventral crushing. A distinct nasofrontal hinge separates the strongly projected intercondylar eminence, deep infracotylar fossa, upper jaw from the braincase. A longitudinal furrow extends to the and evidence of two hypotarsal canals. base of the first pseudotooth, which is blunt and subtriangular. The pseudoteeth exhibit a bilaterally symmetrical size progression, Results with the first two large pseudoteeth separated by two smaller Modeled flight properties calculated in Flight 1.25 (2) indicate pseudoteeth and the number of intervening small pseudoteeth that P. sandersi attained high lift:drag ratios in gliding flight and increasing to three in the caudal part of the jaw. Impressions of the that it was able to glide at fast speeds with low sink rates (Fig. 2). cerebral hemispheres indicate that the sagittal eminence was At speeds yielding maximum range (10.6–17.0 m/s), lift:drag ratio strongly projected and extended to near the rostral margin of the is predicted to have reached values of 21.0–23.9. Critically, all 24 cerebral hemisphere, which is in contrast to the poorly developed permutations support the same general glide polar shape. Among sagittal eminence reported in the Early pelagornithid extant soaring birds, the most similar values are observed in al- (24). The mandibular ramus is separated into two batrosses. Modeled flight properties for result in lower sections by a complex intraramal joint. Accounting for a small lift:drag ratios, whereas both condors and show slower missing portion at the rostral tip, the lower jaw articulated well true air speeds at the same sinking speed. rostral to the level of the occipital condyle, like in P. longirostris Estimating gliding performance does not require knowledge (10). The scapula is remarkably small, like in P. chilensis (10). The of flight muscle energy output or flapping style. Power curve furcula shows a shallow facet that may have formed an articulation calculations require estimating these additional parameters and

2of6 | www.pnas.org/cgi/doi/10.1073/pnas.1320297111 Ksepka Downloaded by guest on September 26, 2021 Fig. 2. (A) Glide polars and (B) lift:drag ratios for P. sandersi modeled in Flight 1.25 (2). Results of 24 analyses using different combinations of mass (21.9–40.1 kg), wingspan (6.06–7.38 m), and aspect ratio (13.0–15.0) estimates in blue; modeled values for a (Fregata magnificens; red), albatross (Diomedea chrysostoma; black), and (Coragyps atratus; green) from the Wings database in Flight 1.25 are shown for comparison. Individual analyses are pre- sented in SI Appendix.

thus, entail more uncertainty. Modeled power curves (Fig. 3) do similarity with the largest albatrosses. Analyses presented here not unambiguously resolve whether P. sandersi was capable of indicate that this species was capable of efficient gliding flight. horizontal flapping flight under aerobic power. In the results of Regardless of whether horizontal flapping flight was possible EVOLUTION analyses using the lowest body mass estimates and the highest under aerobic power, a running takeoff can aid launch. Once wingspan estimates for P. sandersi, most of the power curve falls airborne, birds can also obtain and renew power from external under the level of the maximum power available from aerobic forces, such as air currents (2, 12, 16). metabolism (Fig. 3, green lines), consistent with horizontal flap- Larger sizes lead to greater soaring efficiency. In particular, ping flight capabilities at a range of speeds. However, analyses longer wings reduce the relative size of wingtip vortices, reducing using higher mass estimates and lower wingspan estimates result drag and thereby, improving glide ratio (4). Modeled flight in power curves that fall completely above the maximum power properties indicate that P. sandersi attained high lift:drag ratios available from aerobic metabolism (Fig. 3, dark blue lines). It in gliding flight and was able to glide at fast speeds with low sink EARTH, ATMOSPHERIC,

should be noted that the latter results do not require that P. sandersi rates (Fig. 2). By virtue of their remarkably long wings, pela- AND PLANETARY SCIENCES was incapable of launching and soaring, because power can also gornithids could achieve a similar minimum sink rate to frig- be obtained from air currents and renewed by dynamic soaring. atebirds at optimal glide speed, despite having higher inferred Intervals of flapping flight may also have been possible using . In turn, higher wing loading results in faster gliding anaerobic power. Physiological scaling suggests that anaerobic flight speeds. Overall, the modeled parameters, which are robust to muscle fraction should be high for a bird with the 21.9–40.1 kg uncertainty in wingspan, aspect ratio, and mass estimates, sug- estimated mass of P. sandersi (25). Thus, the powered flight results gest that P. sandersi was able to maintain an expansive range to are best interpreted as supporting a low power margin, but these exploit feeding patches. results do not necessarily rule out intervals of powered horizontal However, large size also conveys disadvantages, hindering flight or standing takeoff (Table S1). Full results of all analyses are movement on the ground or sea surface and increasing vulner- provided in SI Appendix. ability to breakage under high-stress conditions. When encountering unfavorable winds, Wandering Albatrosses alight Discussion on the ocean surface (26), using a running launch to take off P. sandersi attained the largest known avian wingspan (∼6.4 m), again and flapping flight to climb. Extant frigatebirds, which have which raises questions about the paleoecology of giant pela- wingspans of ∼3 m and highly reduced hind limbs, are incapable gornithids. As size increases, power required for flight increases of ocean landings (27). Extreme modification of the proximal more rapidly than power available for flight (2). Thus, aero- end of the humerus (8) and reduction of the hind limb make it dynamic theory suggests an upper limit of 12–16 kg for aerobi- debatable whether P. sandersi was capable of taking off from the cally powered, continuous flapping flight (1, 2, 13). However, ocean surface. If P. sandersi was unable to launch from the ocean even soaring birds must retain some ability to flap to survive in surface, plunge diving and surface dabbling feeding strategies variable wind environments (13). Otherwise, grounding could would be ruled out. Prey captured near the surface while in flight prove fatal. Flapping frequency provides another theoretical were potential food sources for P. sandersi, which is in keeping limit for flight. Flapping frequency scales to body mass in such with the proposed gripping or trapping function of the pseudo- a way that predicts that albatross-like birds would be unable to teeth (8, 18). Kleptoparasitism and nest raiding may also have stay aloft at sizes above 5.1-m wingspan (13). P. sandersi sur- been options, because P. sandersi would have greatly exceeded passed theoretical mass limits for flapping flight and wingspan the size of contemporary and Procellariiformes from the limits for soaring flight based on previous models, but the ex- Chandler Bridge Formation (SI Appendix). tremely elongated wings and reduced hind limbs indicate it was Extant birds exploit various strategies to survive in marine a volant bird. Such large size was aerodynamically viable, be- environments. Wandering Albatrosses (D. exulans) use a tendi- cause P. sandersi was proportionally much longer winged than an nous shoulder lock to hold the wing in a horizontal position (28) albatross: at two times the wingspan but only two to four times and dynamic soaring near the boundary layer above waves the mass, the fossil species departed greatly from geometric to achieve metabolically efficient flight. Frigatebirds pursue

Ksepka PNAS Early Edition | 3of6 Downloaded by guest on September 26, 2021 process is preserved. This estimate agrees with the other measurable dimensions of the humerus: proximal width measures 92.5 mm, and total length ranges from 10.0 to 11.5 times proximal width in complete humeri of other giant Pelagornis specimens (10, 17). Width is, thus, consistent with a length of 925–1,064 mm. Body width (distance between glenoid fossae) was estimated at 287.5 mm and scaled from the 250-mm body width of P. chilensis, which is based on the intact furcula of that species (10). This value is consistent with the observation that body width scales isometrically in closely related birds (31). This value results in body width accounting for 3.9–4.7% of total wingspan (depending on method used to estimate primary feather length), consistent with the ob- servation that body width in birds accounts for 4.12% of total wingspan on average (31). Thus, total skeletal wingspan is estimated at 5.214 m. Primary extend the length of the wing beyond that of the ar- ticulated skeleton in all birds, and skeletal wing to primary feather length proportions vary greatly among (32). Given this uncertainty, three methods for estimating primary feather length were used. The only direct evidence for feather proportions in Pelagornithidae comes from a specimen of P. orri that preserves flight feathers in association with a nearly complete skeleton (7). The longest intact feather from that specimen measures 400 mm, but it is uncertain whether this feather corresponds to the first primary, which is typically the longest feather and contributes directly to maximum wingspan. Scaling up this 400-mm feather length based on the relative length of the wing bones would yield a first primary length of 550–630 mm for P. sandersi (the range is because of differences in wing bone proportions in P. orri and P. chilensis). Because the isolated P. orri feathers are propor- tionally short given wing skeleton length and therefore, likely to represent shorter feathers from a more proximal region of the primary series (7), 550 mm can be considered a minimum estimate. Regressions calculated from the wing proportions of extant birds were used as a second set of estimates. Three recently published equations (32) were applied: one equation based on a regression ignoring phylogenetic relationships and two equations using independent contrasts based on different global phylogenies for Aves. Ap- plying these regressions to P. sandersi results in estimates of first primary length ranging from 441 to 603 mm. A third estimate was obtained by ex- Fig. 3. Power curves for P. sandersi calculated in Flight 1.25 using (A)the trapolating from the proportions in large Procellariiformes. Spread wing 21.9-kg mass estimate and (B) the 40.1-kg mass estimate with maximum specimens including all skeletal elements are rare in museum collections (32). estimated aerobic power for comparison. A and B each display the results of The humerus is typically removed or truncated from spread wings, making it 12 iterative analyses with alternate combinations of wingspan and aspect difficult to obtain precise measurements of the skeletal length and wing ratio estimates. In A, horizontal flight under solely aerobic power is sup- length of a single individual. One suitable spread wing with a completely ported by iterations with 6.4-m wingspan and 14.0–15.0 aspect ratio (light intact bony wing was identified from the giant Macronectes gigan- blue) as well as all iterations with 7.38-m wingspan (green). All other runs teus (National Museum of Natural History, Smithsonian Institution: USNM did not support horizontal flight capabilities under solely aerobic power. 631190). In this individual, the first primary accounted for 30.6% of overall Individual results for all 24 runs are provided in SI Appendix. wing length. If proportions were similar in P. sandersi, it would indicate a primary length of 1.083 m. Although this method provides the highest estimate, it is worth noting that the feather:skeleton length proportions a different strategy, taking advantage of ascending air currents to from the procellariiform are lower than in measured [e.g., feathers maintain high altitudes and occasionally descending to the sur- accounted for >33% of wing length in Cathartes aura (USNM 561353), and face to exploit patchily distributed feeding opportunities (29). the spread wing in this specimen was truncated, indicating that the true Although it remains unknown whether P. sandersi evolved a value was higher]. These data, thus, support a total wingspan of 6.06–7.38 m for P. sandersi tendinous strut similar to albatrosses, estimated wing loading depending on feather estimate method. For comparison, the most complete – 2 (51.2 160.3 N/m ) and modeled flight properties (Fig. 2) support wing element of the teratorn A. magnificens is a humerus estimated at 570 a more albatross-like than frigatebird-like flight style. The global mm in length. No fossil feathers are known for teratorns, but scaling based distribution of pelagornithid is also inconsistent with on the relative feather length in the extant Gymnogyps californicus a reliance on ascending air currents, which restricts extant frig- (California ) results in total wingspan estimates of 5.70–6.07 m (15), atebirds to the tropics. whereas applying the three regressions (32) results in wingspan estimates of – Our understanding of the ecology of pelagornithids is only 5.09 5.57 m. Past estimates of 7 m or more (15, 16) are based on extrapo- lation from mass estimates rather than wing elements, but these estimates starting to develop. Data reported here suggest that they were require leading primary lengths of ∼1.5 m, which contrasts sharply with both remarkably efficient fliers, which together with their global dis- ratios seen in extant terrestrial soaring birds and the observation that pri- tribution across all seven continents (8–10, 30) and long temporal mary length exhibits negative allometry with increasing body size (32). range, makes the cause of their ultimate all of the more Mass estimation for extinct birds has relied primarily on the circumference of mysterious. the weight-bearing bones of the hind limb. Two regressions (33) for estimating the mass of birds based on a large sample of extant taxa were applied: Methods log m = ð2:411 × log CfÞ − 0:065 and Size Constraints. Skeletal wing length was estimated at 2.463 m (per wing) log m = ð2:424 × log CtÞ + 0:076, based on intact elements (Table 1) and the proportions in P. chilensis. Skeletal proportions of the wing show little variation within Pelagornis as where m is mass (grams), Cf is the least femur circumference (millimeters), far as can be established from reasonably complete . The 2.463-m and Ct is the least tibiotarsus circumference (millimeters). value is conservative given that this wing length is 115% that of P. chilensis, Because of partial flattening, it is not possible to directly measure the cir- whereas directly comparable element lengths range from 115% (femur) cumference of the femur or tibiotarsus in P. sandersi. However, the proportions of to 126% (skull) of those in P. chilensis. As preserved, the humerus measures the preserved elements are closely similar to those in P. chilensis. Isometric scaling 810 mm in length, and complete length is estimated to be 940 mm, given based on length differences results in estimated circumferences of the femur and that no portion of the musculus brachialis fossa or dorsal supracondylar tibiotarsus of 67.2 and 73.7 mm, respectively. These values are consistent with

4of6 | www.pnas.org/cgi/doi/10.1073/pnas.1320297111 Ksepka Downloaded by guest on September 26, 2021 Table 1. Measurements (in millimeters) from Pelagornis sandersi holotype (ChM PV4768) Measurement Value

Skull length 569.0 Humerus preserved length 810.0 Humerus estimated complete length 940.0 Humerus proximal width 92.5 Femur length 176.8 Femur proximal width 40.9 Tibiotarsus length 280.0 Tibiotarsus distal width 38.0 Tarsometatarsus length >150.0 Wingspan (feathers estimated from scaling P. orri feathers) 6,276–6,436 Wingspan (feathers estimated from skeleton:feather regressions) 6,058–6,382 Wingspan (feathers estimated from extant Procellariiformes) 7,380

measurements around the intact but partially flattened bones. Applying the re- was determined using table 2.1 in ref. 2. This reference point provides a value gression from femur circumference results in a mass estimate of 21.9 kg while of 9.793 m/s2 for the analyses. applying the regression from tibiotarsus circumference results in a mass estimate For the power curve analyses, maximum continuous metabolic output was of 40.1 kg. A recently published regression from femur circumference (34) based estimated at 78–117 W for P. sandersi based on the observation that power < 2/3 on a larger dataset yielded a mass estimate of 21.8 kg ( 1% difference from the available scales according to the equation Pavailable = 10(mass) in verte- valueusedintheanalyses). brates (35). Power required was estimated in Flight 1.25. Given the lack of direct data on pelagornithid musculature or flight style, values falling within Flight Modeling. The software package Flight 1.25 (2) was used to model the range of modern birds were selected. Flapping flight style with a flight flight parameters for P. sandersi. This program requires user specification of muscle fraction of 0.17 was specified, which is the default value in Flight 1.25 environmental and wing-shape variables. Given the uncertainty inherent to and based on the observation that flight muscle mass averages 17% of

estimating size parameters in fossil taxa, 24 iterations of the analyses were overall mass across almost all birds (36). A conversion efficiency of 0.23 was EVOLUTION conducted with different combinations of mass estimates (21.9 and 40.1 kg), used along with a metabolism rate calculated with the equation basal wingspan estimates (6.06, 6.13, 6.4, and 7.38 m), and aspect ratios (13.0, metabolism rate = 3.79(mass)0.723 and a respiration factor of 1.1, all of which 14.0, and 15.0). Wingspan reduction was set to the linear option in all represent default values for fuel to muscle work conversion efficiency based analyses, which reflects the observation that gliding birds do not adjust their on empirical work (2). wings for minimum drag (2). All inputs not explicitly mentioned above were left at default settings. ACKNOWLEDGMENTS. I thank James Malcom for reporting the discovery and For all calculations, air density was set using the International Standard assisting in collection, Al Sanders for leading the collection and providing Atmosphere values for and 15 °C, yielding a density of 1.225 kg/m3. helpful discussion, Carl Borick, Grahame Long, and Jennifer McCormick for Although conditions encountered by birds will vary with weather, this collections access and hospitality at the Charleston Museum, Storrs Olson for

density provides a baseline for comparisons. Results show little sensitivity to arranging initial preparation of the specimen, Liz Bradford for creating the EARTH, ATMOSPHERIC, assumptions about temperature or flight altitude; for example, doubling line artwork, Michelle Sclafani and Alyssa Stubbs for assisting with measure- AND PLANETARY SCIENCES ments, Helen James and Chris Milensky for access to spread wings, and temperature or increasing altitude to 1,000 m does not shift any of the es- David Rubilar-Rodgers for sharing images of P. chilensis. Comments by timated parameters in SI Appendix, Table S2 by more than 5%. Gravity varies Michael Habib and three anonymous reviewers substantially improved ’ slightly across latitudes because of the centripetal force caused by Earth s this manuscript. This work was supported by National Science Foundation rotation and the fact that our planet is not a perfect sphere. Gravity at sea Award DEB: 0949899 and National Evolutionary Synthesis Center Grant level at 30°S latitude (the approximate paleolatitude of the fossil locality) NSF EF-0905606.

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