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Home , Archaeolemur, Babakotia, Hadropithecus, Lemur, Megaladapis, Palaeopropithecus

COMMENTARY

Reconstruction of an extraordinary extinct from

Ian Tattersall* Division of , American of Natural History, New York, NY 10024

he minicontinent of Madagas- cus and its close relative car has been separated by 350 have been reported as pronograde ter- miles of ocean from its neigh- restrial quadrupeds (10, 11) (Fig. 1). bor for at least the past These two last genera, and the ex- T120 million , i.e., since long before tremely short-faced and deep-skulled the beginning of the Age of in particular, were also (1). As a result, the island’s and exceptional in showing extended dental fauna show extremely elevated levels of development schedules that presumably endemicity overall (2), and its native reflected prolonged overall develop- mammals show a curious combination of mental periods (12); and compared low diversity at the ordinal level with with other members of the Malagasy extraordinarily high diversity at lower fauna (living and extinct), they taxonomic levels (3). Today, for exam- were also highly encephalized (4, 9). Fig. 1. Reconstruction by the artist Stephen Nash ple, Madagascar harbors an astonishing The first remains of Hadro- of a Hadropithecus individual as it may have ap- 30% of all primate families and some pithecus were recovered at around the peared in . Pelage coloration and distribution are, of course, conjectural. 21% of all primate genera (3), all of turn of the 20th century from the An- them represented nowhere else. Yet, drahomana cave, near the southern tip high as these figures are, they would of Madagascar. These specimens were complete ) that Ryan and co- have been substantially higher a mere sent at various times to Ludwig Lorenz authors (4) report in this issue. They 2,000 years ago, before the arrival of von Liburnau at the Imperial Austrian demonstrate the match through the Madagascar’s first inhabitants Academy of Sciences. In 1899, on the ‘‘virtual’’ refitting of the new frontal and the probably not coincidental ex- basis of its highly distinctive , parts to the 1902 cranium via medical tinction of a substantial proportion of Lorenz assigned an (adult) lower jaw to CT imaging. The fit is exact. Similar the island’s primate (lemur) fauna. In the new and Hadropithe- on-screen manipulations also permitted this issue of PNAS, Ryan et al. (4) re- cus stenognathus, and, as the name he mirror-imaging of complete com- port how new fossil discoveries and the chose implies, concluded that it had ponents on one side to broken areas use of computer-aided visualization affinities (13). Later finds, which in- on the other, and the of the techniques have significantly advanced cluded an incomplete subadult skull and lower jaw similarly reconstructed. The our knowledge of cranial construction some postcranial parts, demonstrated to result is a detailed three-dimensional and body proportions in Hadropithecus, Lorenz that his new form was in fact an image of the Vienna Hadropithecus one of the most unusual of the recently ‘‘advanced’’ lemur that grouped with the skull, lacking only the anteriormost extinct lemur genera. previously described Archaeolemur (14). extremities of the lower and upper The extinct are well docu- In 1931, an adult skull of H. stenog- jaws. Beyond the considerable intrinsic mented from ‘‘subfossil’’ remains col- nathus was discovered at the site of interest inherent in the almost com- lected at numerous sites ranging from Tsirave´in southwestern Madagascar plete image of one of only two crania Ϸ500 to Ϸ26,000 years old (5). And to (15); but the species remained among known of a primate species that boasts describe Hadropithecus as unusual the most poorly understood of the ex- a truly unique and altogether remark- among them is to say that it is unusual tinct lemurs, its known remains conspic- able morphology, the new reconstruc- indeed. The surviving lemurs of Mada- uously lacking a full associated skeleton. tion is notable in uniting pieces resid- gascar all lie well toward the lower end In 2003, more than a century after ing in entirely different of the body-size distribution, the initial find, a group that included separated by an ocean. The original with body weights ranging from Ϸ50 g some of the authors of the current skull components were CT scanned in to 6.0 kg (3). All, with one very partial PNAS contribution returned to Andra- Vienna, where they form part of the exception, are also strictly arboreal. In homana. There they found numerous collections of the Natural History Mu- contrast, every one of the eight subfos- bones of an immature postcranial skele- seum, whereas the two new frontal sil genera was substantially larger in ton that, astonishingly, turned out to fragments were scanned at Pennsylva- size, with estimated body weights rang- belong to the same individual as the ini- nia State University, where the result- ing from Ϸ10 kg to Ϸ200 kg (6). tial subadult skull and a handful of post- ing digital images were electronically Moreover, the extinct forms were as cranial pieces that Lorenz had reported united. diverse adaptively as they were in size. with it (4, 11, 14). The positive association of the cra- Thus the ‘‘ lemurs’’ and Clinching evidence that the two sets nium with a more or less complete were among the most of remains come from the same indi- postcranial skeleton of Hadropithecus specialized arboreal suspensory forms vidual is provided by two frontal frag- ever to evolve among the mammals ments from the 2003 excavation that (7); the extremely odd was perfectly match the missing areas of I.T. wrote the paper an arboreal vertical clinging form (8) the original cranium described a hun- The author declares no conflict of interest. with positional behaviors that have dred years earlier. It is this positive See companion article on page 10699. been compared with those of the association between the two sets of *E-mail: [email protected]. (9); and, in stark contrast, Hadropithe- remains (and the resulting quasi- © 2008 by The National Academy of Sciences of the USA

www.pnas.org͞cgi͞doi͞10.1073͞pnas.0806111105 PNAS ͉ August 5, 2008 ͉ vol. 105 ͉ no. 31 ͉ 10639–10640 Downloaded by guest on October 1, 2021 stenognathus provided an opportunity visible in the CT scan, suggests a rela- of the most unusual and interesting to reevaluate the bodily proportions tive lack of agility. The unique dental ever to have evolved. and of this highly apomor- morphology of this form has been seen The research reported in this issue of phic primate species. The relatively as evidence of seed eating, but stable PNAS was accomplished by a joint high encephalization of this individual carbon isotope analyses cited here sug- American–Malagasy–Austrian team that relative to members of other lemur gest that grasses may have been con- provides a model for future interna- species was confirmed, as was the sta- sumed. And this is only the beginning: tional collaborations in the area of pri- tus of Hadropithecus as a terrestrial The existence of a substantially com- mate , and it further points the quadruped, albeit one that could climb plete skeleton of a single individual of way toward the refinement of knowledge fairly readily. However, the size of the Hadropithecus will provide a firm plat- in the field by the application of new semicircular canals of the inner , form for future understanding of one technologies.

1. Coffin MF, Rabinowitz P (1987) Reconstruction of Madagas- 7. Jungers WL, et al. (1997) Phalangeal curvature and elements of Hadropithecus stenognathus from Andra- car and Africa: Evidence from the Davie Fracture Zone and positional behavior in extinct sloth lemurs (Primates, homana Cave, southeastern Madagascar. J Hum Evol the Western Somali Basin. J Geophys Res 92:9385–9406. Palaeopropithecidae). Proc Natl Acad Sci USA 51:395–410. 2. Goodman SM, Benstead JP, eds (2003) The Natural 94:11998–12001. 12. Schwartz GT, et al. (2002) Dental microstructure and (Chicago Univ Press, Chicago). 8. Wunderlich RE, et al. (1996) New pedal remains of. life history in subfossil Malagasy lemurs. Proc Natl Acad 3. Mittermeier RA, et al. (2006) Lemurs of Madagascar (Con- Megaladapis and their functional significance. Am J Sci USA 99:6124–6129. servation International, Washington, DC), Second Ed. Phys Anthropol 100:115–139. 13. Lorenz von Liburnau L (1899) Einen fossilen Anthro- 4. Ryan TM, et al. (2008). A reconstruction of the Vienna 9. Walker AC (1974) Locomotor adaptations in past and poiden von Madagascar. Anz Kais Akad Wiss Wien skull of Hadropithecus stenognathus. Proc Natl Acad present primates. Primate Locomotion,ed 36:255–257. Sci USA 105:10699-10702. Jenkins FA (Yale Univ Press, New Haven), pp 349– 14. Lorenz von Liburnau L (1902) U¨ ber die Hadropithecus 5. Burney DA, et al. (2004) A chronology for late prehis- 382. stenognathus. Lz Denkschr Kais Akad Wiss Wien toric Madagascar. J Hum Evol 47:25–63. 10. Godfrey LR, et al (2005) New insights into old lemurs: 72:243–254. 6. Godfrey LR, Jungers WL (2003) Subfossil lemurs. The Nat- The trophic adaptations of the Archaeolemuridae. Int J 15. Lamberton C (1938) Contribution a`la connaissance de ural History of Madagascar, eds Goodman SM, Benstead Primatol 26:825–854. la faune subfossile de Madagascar. Note III. Les Hadro- JP (Univ of Chicago Press, Chicago), pp 1247–1252. 11. Godfrey LR, et al. (2006) New discoveries of skeletal pithe`ques. Bull Acad Malg 27:75–139.

10640 ͉ www.pnas.org͞cgi͞doi͞10.1073͞pnas.0806111105 Tattersall Downloaded by guest on October 1, 2021