Megafaunal meiolaniid horned turtles survived until early human settlement in Vanuatu, Southwest Pacific
- aSchool of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia;
- bArchaeology and Natural History, College of Asia-Pacific, Australian National University, Canberra, ACT 0200, Australia; and
- cSchool of Archaeology and Anthropology, College of Arts and Social Sciences, Australian National University, Canberra, ACT 0200, Australia
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Edited* by Patrick V. Kirch, University of California, Berkeley, CA, and approved July 12, 2010 (received for review May 3, 2010)

Abstract
Meiolaniid or horned turtles are members of the extinct Pleistocene megafauna of Australia and the southwest Pacific. The timing and causes of their extinction have remained elusive. Here we report the remains of meiolaniid turtles from cemetery and midden layers dating 3,100/3,000 calibrated years before present to approximately 2,900/2,800 calibrated years before present in the Teouma Lapita archaeological site on Efate in Vanuatu. The remains are mainly leg bones; shell fragments are scant and there are no cranial or caudal elements, attesting to off-site butchering of the turtles. The new taxon differs markedly from other named insular terrestrial horned turtles. It is the only member of the family demonstrated to have survived into the Holocene and the first known to have become extinct after encountering humans.
Meiolaniid turtles (Chelonia: Meiolaniidae) are an extinct group of large-bodied, fully terrestrial eucryptodire turtles that were confined to the Southern Hemisphere. These bizarre turtles are characterized by cranial horns or frills developed from the squamosals and a tail bearing a heavily ossified tail club (1–5). Meiolaniids were confined to the tertiary of South America and the Australia–southwest Pacific region (Fig. 1 and Table S1). Late Pleistocene Australian forms include the very large but poorly known Ninjemys oweni (5, 6) and an indeterminate Meiolania species (7). Their demise is included in the Pleistocene megafaunal extinctions that followed human arrival approximately 50,000 y ago (8); however, temporal overlap with humans has not been demonstrated (9). The most well known is Meiolania platyceps from Pleistocene calcretes on Lord Howe Island, 630 km east of Australia (1, 3, 5, 10). Elsewhere in the southwest Pacific, sparse and fragmentary meiolaniid remains, considered to be of Pleistocene age, have been found in New Caledonia (Pindai Caves, Walpole Island, Tiga Island), and on Vitilevu, Fiji (5, 11–13) (Fig. 1 and Table S1). Thus, although meiolaniids were widely distribution in the southwest Pacific, it is not known whether any survived into the Holocene, or if humans were implicated in their extinction. Here we report a previously undescribed locality and, geologically, the youngest occurrence for meiolaniids, providing evidence of temporal overlap with humans and unequivocal evidence that this interaction resulted in their extinction.
Map of southwest Pacific showing locations where meiolaniid remains have been discovered: 1, Lord Howe Island (Australia); 2, Pindai Caves (New Caledonia); 3, Walpole Island (New Caledonia); 4, Tiga Island (New Caledonia); 5, Teouma, Efate Island (Vanuatu); and 6, Viti Levu Island (Fiji).
Results and Discussion
The meiolaniid bones reported here derive from the formerly-coastal Lapita cemetery and midden site at Teouma on the island of Efate, Vanuatu (14) (Fig. S1). People of the Lapita culture were the first humans to colonize the Vanuatu/New Caledonia/Fiji region of the southwest Pacific 3,100 to 3,000 y ago (15–17). The turtle remains reported here were excavated from 275 m2 of the cultural deposits by two of the present authors (M.S. and S.B.) during 2004 to 2006 (SI Text). The site is well stratified, as shown in Fig. 2, with meiolaniid bones abundant and confined to the cemetery levels and basal layers of the later midden deposits (layer 2).
Southern section of Teouma excavation at the rear of the reef terrace (2009) showing the clearly stratified deposits. L1 indicates the black tephra-rich soil, L2 indicates the concentrated midden deposit, L3 indicates the yellow tephra, and L4 indicates the uplifted reef.
The site began as a cemetery, the oldest yet found in the Pacific Islands, approximately 3,100 or 3,000 calibrated years before present (cal BP) (14). After a subsequent period of only ephemeral visitation to the site, a village became established there approximately 2,900 cal BP. This sequence is underpinned by radiocarbon dating of shell, bone, and charcoal samples from associated human burials and midden materials (14,18) (SI Text).
The ages of the turtle bones are constrained by this archaeological sequence. Two accelerator MS radiocarbon dates on collagen from meiolaniid bones from the basal levels of layer 2, calibrated to 2,890 to 2,760 cal BP at 94.3% probability (SI Text), support this inference. The associated δ13C values (−25.4, −23.1) are consistent with a terrestrial herbivorous diet for these turtles. The midden deposits in some areas exceed 1 m in thickness, but turtle bones were only ever found in situ in the lowest levels. The upper part of the midden cannot date to later than 2,500 cal BP on the basis of pottery typology, which is well dated at other Efate sites (19).
Ten specimens were identified as marine turtle, but are not hereafter discussed. The majority belong to a relatively large terrestrial turtle as shown by, for example, humeri and femora of similar length, proximal and distal ends expanded, and shafts markedly sigmoidal; pectoral girdle with angle between the dorsal scapular process and acromion markedly wider than the approximate 90° observed in marine turtles; coracoid short, fan-shaped caudally; phalanges short and robust; and unguals robust and slightly recurved (Figs. 2 and 3). The material includes 405 bones and numerous indeterminate bone/carapace fragments attributed to meiolaniids. Identifiable specimens are mainly limb bones from at least 30 individuals (Table 1), with cranial and caudal elements absent and shell pieces scant and fragmentary. Many of the bones are broken and often the epiphyses have been lost. They are identified as meiolaniid by the following apomorphies (4, 5): (i) humerus with ectepicondylar foramen beginning as a groove dorsally, but distally penetrating the condyle to open ventrally; (ii) ulna with a distinct ridge dorsoproximally, extending distally from articular facet, forming a flat radioulnar articulation medially; (iii) digits with two phalanges and a robust ungual; (iv) shell fragments that are relatively thin and bear pits and grooves without a regular pattern on their outer surface; and (v) presence of dermal armor on shell margin.
Pectoral elements of ?M. damelipi. (A–D) Right humeri, Holotype AMF136641 (A) and AMF136640 (B–D), in (A and B) dorsal, (C) caudal, and (D) ventral aspects. (E, I, and J) Left ulnae, AMF136648 (E and J), and proximal half of AMF.136647 (I) in (E) medial and (I and J) dorsal aspect. (F and G) left scapula AMF136644 in (F) ventral and (G) lateral view. (H) Right coracoid AMF136652 in dorsal aspect. (ca, coracoid articulation; med, medial process; lat, lateral process; ac, acromion; dsp, dorsal scapular process; ect, ectepicondyle; ef, ectepicondylar foramen, which in unbroken specimens penetrates the ectepicondyle to emerge on the ventral facies; ent, entepicondyle; gl, glenoid; ra, radial-ulnar articulation; r, ridge forming boundary of dorsal-medial boundary low; sig, sigmoid notch.) *Area is flat, not a deep sulcus as in M. platyceps. See SI Text for associated data. (Scale bars, 50 mm.)
Element frequency of meiolaniid remains from the 2004 to 2006 excavations at Teouma, Efate, Vanuatu
The Vanuatu meiolaniid differs from all named Pleistocene meiolaniids, so here we erect a new taxon for it.
Systematic Paleontology.
Meiolaniidae Boulenger, 1887; ?Meiolania Owen, 1886 (20); and ?Meiolania damelipi sp. nov.
Holotype is AMF136641, right humerus, collected layer 2, Unit 3.3–3.4, Area 3B, Teouma Lapita site, Efate, Vanuatu, 2006 (Fig. 3). Etymology is for Willie Damelip, originally of Ambrym Island (SI Text). Diagnosis is a meiolaniid differing from other Pleistocene species with more gracile longbones; shoulder girdle with coracoid unfused, well developed dorsal and acromion processes diverge at approximately 105°; minor and major femoral trochanters ventrally enclose a deep intertrochanteric fossa; much smaller than Ninjemys oweni. Measurements of holotype are as follows: total length, 95 mm; maximum proximal width, 39 mm; minimum shaft width, 15 mm; and maximum distal width, 35 mm. Paratypes are all elements shown in Figs. 3 and 4; measurements are provided in Table 2.
Pelvic and carapace elements of ?M. damelipi. (A) Left femur AMF136642 in caudal view; (B and C) Right tibia AMF136651 in (B) ventral and (C) dorsal view. (D and E) Dermal armor of carapace in caudal (D) and ventral (E) views of AMF136646. (F) Marginal fragment of carapace with gutter AMF136649. (G and H) Ungual phal AMF136664 in (G) ventral and (H) dorsal aspects. (pat, patellar tendon attachment not raised in ridge; tm, trochanter major; tub, tuberosity.) See SI Text for associated data. (Scale bars, 50 mm in A–F, 10 mm in G and H.)
Measurements (mm) of the Holotype (AMF.136641) and the paratypes of ?M. damelipi n. sp
Given the absence of the diagnostic material of the skull and the tail, and minimal peripheral material of the carapace or plastron, we only tentatively refer this new species to Meiolania. On biogeographic and temporal grounds, we consider it unlikely that the insular ?M. damelipi was conspecific with the Miocene taxa described from Australia (SI Text and Table S1). Whether it differed from other unnamed taxa from the New Caledonian region cannot be established from the material at hand. The preserved elements allow significant comparison with M. platyceps material in the Australian Museum, described by Gaffney (5).
Humeri (Fig. 3 A–D) have less expanded ends than in M. platyceps. Estimated lengths range from 40 to 140 mm, with a maximum shaft diameter of 30 mm. As in M. platyceps, the proximal articular surface is hemispherical and offset dorsally from the shaft, the medial process is larger than the lateral one, and proximal width is greater than distal width. The ectepicondylar foramen begins as a distinct groove, wider than in M. platyceps, on the dorsal facies of the shaft, before penetrating the ectepicondyle to open ventrally. Humeri differ from M. platyceps and M. mackayi (11) with a less expanded lateral process and a more proximally projecting medial process.
Ulnae (Fig. 3 E, I, and J), as in M. platyceps, have proximally an extremely well developed olecranon process and sigmoid notch, and a well defined radioulnar articulation (5). Radii are more elongate and the rugosity for biceps superficialis on the shaft is smaller than in M. platyceps.
The shoulder girdle (Fig. 3 F–H) is triradiate: as in M. platyceps, the glenoid is not supported by a neck; the well developed dorsal and acromion processes diverge at approximately 105° compared with 120° in M. platyceps and other terrestrial turtles (5); the coracoid (Fig. 3H), unlike M. platyceps, is not fused to the glenoid and is more elongate. A wide scapular angle is usually correlated with a high body profile (5) suggesting that ?M. damelipi had a low body profile, somewhat more like marine turtles.
Femora (Fig. 4A) are stocky and range from 45 to 145 mm in shaft length; the head is large and hemispherical, being wider than long, and directed more dorsally to the shaft than in M. platyceps, such that it does not project proximally past the trochanter major. The minor and major trochanters are distinct from the femoral head, but unlike M. platyceps, have similar proximal extent and are linked ventrally by a bony web to enclose a deep intertrochanteric fossa.
Ankle, wrist, and digit elements are uncommon, but the few unguals are blunt, dorsoventrally thick, and ventrally flattened as in M. platyceps (Fig. 4 G and H).
Shell fragments of ?M. damelipi are similar to those of meiolaniids in having a thin dense outer bone layer and finely cancellous internal structure, but differ with a smoother external texture, and at least part of the carapace margin is concave dorsally. Dermal armor was present on the carapace (Fig. 4 D and E).
The size of ?M. damelipi can be compared with that of M. platyceps from the dimensions of the long bones. Femora and humeri were as long as 145 mm and 140 mm, respectively, similar to those in AMF57984 with a shell length of 1 m. However, larger turtles were present as one section of shoulder girdle preserves a glenoid cavity with a diameter of 40 mm compared with 30 mm in AMF57984.
These data show that the meiolaniid radiation in the southwestern Pacific region was more extensive than previously recognized (5). Dispersal to and between islands of this region would have been easily achieved by meiolaniids. Terrestrial turtles are highly buoyant (21) and some, e.g., Dipsochelys giganteus, are known to have survived in oceans without access to fresh water for many weeks (22). Although incapable of directed swimming, they are thus ideal candidates for ocean drifting, which dispersal mode explains the distribution of extant terrestrial turtles in the Indian Ocean (22, 23). There is nothing unique about Vanuatu to explain why meiolaniids survived there until the advent of humans, but could not have done so in other island groups, such as Fiji and New Caledonia. In the Lord Howe group, postglacial sea level rise greatly reduced land area, which in the absence of any evidence of pre-European occupation (24) could have facilitated the extinction of M. platyceps. For archipelagoes that retained islands of significant size in the Holocene, this cannot be the explanation. A poor or absent fossil record for most islands is the probable reason for a lack of other Holocene meiolaniids so discovery of further populations or taxa should be expected on other southwest Pacific islands where adequate habitat existed. Investigations of first contact human southwest Pacific sites will likely extend the record, and reexamination of bones previously interpreted as marine turtle might reveal that some are in fact those of terrestrial turtles.
The discovery of meiolaniid remains at Teouma provides conclusive evidence that they survived into the late Holocene and that humans encountered them. Relatively large numbers of meiolaniid bones occur, particularly in the basal levels of the Teouma midden, dating to approximately 2,900 or 2,800 cal BP, where they overlay burials dated 3,100 to 3,000 cal BP (14). Some burials were associated with meiolaniid carapace fragments (SI Text). In younger layers, they are absent. Remarkably for a Pacific coastal site, bones of marine turtles are rare in the lower layers. Early colonizers of the western Pacific normally hunted sea turtles and impacted many populations (25). At Teouma, large comparatively heavy bodied and fleshy terrestrial turtles were available and were the preferred prey until their disappearance by approximately 300 y after the initial encounter. Skeletal representation (Table 1) is markedly biased toward legs and associated fleshy parts. We infer that most turtles were killed and butchered elsewhere with mainly the fleshy upper limbs being taken back to the village. It seems probable that the first colonists, who created the cemetery at Teouma, and whose habitation sites have not yet been found, had eliminated proximate populations of turtles.
Hunting undoubtedly contributed to the extinction of ?M. damelipi, but may not have been the only cause. In the Mascarenes (Indian Ocean), where Europeans were the first humans to encounter the terrestrial turtles on Mauritius and Rodrigues, and initial densities were high, intensive exploitation for food rendered all populations extinct in a little more than one century (22). This rapid extirpation of turtles was partly attributed to the introduction of pigs, which prey on young and eggs. Similarly, pigs introduced by Lapita people may have affected the survivorship of Vanuatu meiolaniids. Whatever the exact synergy of factors, meiolaniids were extinct on Efate in Vanuatu within 300 y of the arrival of Lapita people.
The discovery of ?M.damelipi and that it became extinct soon after human arrival fits a recurring pattern across the Pacific. In Vanuatu, similar timed extinctions include a crocodilian and several birds (26, 27). Such losses are widespread and numerous and include crocodilians and large birds in New Caledonia (5, 27), these and large iguanids in Fiji (13), with losses of birds on every island for which a record exists (ref. 27 and references therein). Whether the turtle species known from fossil sites in New Caledonia (12) and Fiji (13) also survived until human arrival has yet to be established. The overall situation is such that in terms of total species, the loss of diversity in the late Holocene for the Pacific exceeds all other areas on Earth.
Materials and Methods
The Teouma Lapita site, located on the south coast of Efate Island, Central Vanuatu, was found in January 2004, following removal of approximately 1,000 m2 of the overlying black ash-rich soil during quarrying. In 2004 to 2006, an area of 275 m2 was excavated using trowels only, and all material was sieved dry or, as in most cases, wet-sieved to retrieve the most complete sample possible (18). Turtle bones were sorted from midden materials by one of the present authors (S.H.). Identification to taxon, element, and side was by two other authors (A.W. and T.H.W.). Radiocarbon analyses were carried out by the Radiocarbon Dating Laboratory at the University of Waikato, Hamilton, New Zealand, with accelerator MS determinations made on the graphitized carbon at the Rafter Laboratory in Lower Hutt, New Zealand (SI Text describes details). The turtle bones described herein are deposited in the Australian Museum, Sydney, and in the Vanuatu National Museum, Port Vila.
Acknowledgments
We thank Fiona Petchey (Waikato University Radiocarbon Laboratory) for help with dating and isotope analyses. We acknowledge the support and assistance of the leaseholder M. Robert Monvoisin and family, the Vanuatu Cultural Centre field worker for the area Silas Alben, and the traditional landowners and community of Eratap Village. The Teouma 2004–2006 Archaeological Project was a joint initiative of the Vanuatu National Museum and The Australian National University (ANU), directed by M.S. and S.B. and Ralph Regenvanu, then Director of the Vanuatu Cultural Centre. This study was funded by the Pacific Biological Foundation, Department of Archaeology and Natural History and School of Archaeology and Anthropology of ANU, Snowy Mountains Engineering Corporation Foundation, Mr. Brian Powell, National Geographic Scientific Research Grant 8038-06, and Australian Research Council Discovery Grant DP0556874.
Footnotes
- 1To whom correspondence should be addressed. E-mail: t.worthy{at}unsw.edu.au.
Author contributions: T.H.W. designed research; A.W.W., T.H.W., S.H., S.B., and M.S. performed research; T.H.W. analyzed data; and A.W.W., T.H.W., S.B., and M.S. wrote the paper.
The authors declare no conflict of interest.
↵*This Direct Submission article had a prearranged editor.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1005780107/-/DCSupplemental.
References
- ↵
- Owen R
- ↵
- Owen R
- ↵
- Gaffney ES
- ↵
- Rich PV,
- Monaghan JM,
- Baird RF,
- Rich TH
- Gaffney ES
- ↵
- Gaffney ES
- ↵
- Gaffney ES
- ↵
- Gaffney ES,
- McNamara G
- ↵
- Roberts RG,
- et al.
- ↵
- ↵
- Gaffney ES
- ↵
- Anderson C
- ↵
- Gaffney ES,
- Balouet JC,
- de Broin F
- ↵
- Worthy TH,
- Anderson AJ,
- Molnar RE
- ↵
- ↵
- Clark G,
- Anderson A
- ↵
- Bedford S,
- Sand C,
- Connaughton S
- Galipaud J-C,
- Swete Kelly M-C
- ↵
- Sand C
- ↵
- Sheppard P,
- Thomas T,
- Summerhayes G
- Bedford S,
- Spriggs M,
- Buckley H,
- Valentin F,
- Regenvanu R
- ↵
- Bedford S
- ↵
- Owen R
- ↵
- Zug GR
- ↵
- Cheke A,
- Hume J
- ↵
- ↵
- Anderson A
- ↵
- ↵
- Mead JI,
- Steadman DW,
- Bedford SH,
- Bell CJ,
- Spriggs M
- ↵
- Steadman DW
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