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1. Description of the subfossil crocodylians from a new Late Pleistocene subfossil site (Tsaramody, Sambaina Basin) in central Madagascar

   Rakotozandry, R. ; Ranivoharimanana, L. ; Ranaivosoa, V. ; Rasolofomanana, N. ; Hekkala, E. ; Samonds, K.E. ( December 2021 , Malagasy nature)

   Madagascar is famous today not only for its unique biodiversity, but also for the high levels of endemism of plants and animals. Less appreciated is the fact that, in the recent past, the island had even greater biodiversity with many other endemic animals such as giant lemurs, elephant birds, pygmy hippopotami, tortoises, and crocodiles that have gone extinct within the past 2000 years. The extinction of many of these groups is thought to be the result of both human activities and environmental change. Most research has focused on the lemurs, hippopotami, and elephant birds. Other recently extinct animals, including the Malagasy horned crocodile (Voay robustus), are relatively poorly known. Madagascar’s subfossil crocodylians include two taxa: the extinct V. robustus (the Malagasy horned crocodile) and the extant Crocodylus niloticus. The latter arrived on Madagascar relatively recently and we know little about the habitat preferences, distributions and ecological interactions (if any) of either species during the Holocene. In order to better understand the recent history of crocodylian extinction in Madagascar, we must first identify which species were present and where they were found. We present here a description of subfossil crocodylian material collected from the newly discovered subfossil site of Tsaramody (Sambaina Basin), a high-elevation wetlandenvironment. At 1655 m, it represents the highest elevation subfossil site on the island. Here we describe both cranial (e.g., premaxillary, jugal, and squamosal “horns”) and postcranial elements (e.g., osteoderms). Our research indicates that crocodile material from Tsaramody appears morphologically to belong to V. robustus, the extinct species. However, oval tuberosities on the frontal bone and a triangular extension of the squamosal bone suggest previously unrecognized variation. 

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2. Subfossil lemur discoveries from the Beanka Protected Area in western Madagascar

   https://doi.org/10.1017/qua.2019.54  

   Burney, David A. ; Andriamialison, Haingoson ; Andrianaivoarivelo, Radosoa A. ; Bourne, Steven ; Crowley, Brooke E. ; de Boer, Erik J. ; Godfrey, Laurie R. ; Goodman, Steven M. ; Griffiths, Christine ; Griffiths, Owen ; et al ( January 2020 , Quaternary Research)

   A new fossil site in a previously unexplored part of western Madagascar (the Beanka Protected Area) has yielded remains of many recently extinct vertebrates, including giant lemurs (Babakotia radofilai, Palaeopropithecus kelyus, Pachylemur sp., and Archaeolemur edwardsi), carnivores (Cryptoprocta spelea), the aardvark-like Plesiorycteropus sp., and giant ground cuckoos (Coua). Many of these represent considerable range extensions. Extant species that were extirpated from the region (e.g., Prolemur simus) are also present. Calibrated radiocarbon ages for 10 bones from extinct primates span the last three millennia. The largely undisturbed taphonomy of bone deposits supports the interpretation that many specimens fell in from a rock ledge above the entrance. Some primates and other mammals may have been prey items of avian predators, but human predation is also evident. Strontium isotope ratios (87Sr/86Sr) suggest that fossils were local to the area. Pottery sherds and bones of extinct and extant vertebrates with cut and chop marks indicate human activity in previous centuries. Scarcity of charcoal and human artifacts suggests only occasional visitation to the site by humans. The fossil assemblage from this site is unusual in that, while it contains many sloth lemurs, it lacks ratites, hippopotami, and crocodiles typical of nearly all other Holocene subfossil sites on Madagascar. 

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3. The stories people tell, and how they can contribute to our understanding of megafaunal decline and extinction in Madagascar

   Nomenjanahary, E.S. ; Freed, B.Z. ; Dollar, L.J. ; Randrianasy, J. ; Godfrey, L.R. ( December 2021 , Malagasy nature)

   Most researchers believe that Madagascar’s megafauna went extinct between 2000 and 1000 years ago. Across Madagascar, fossil specimens of the island’s endemic (and now extinct) pygmy hippopotamuses, elephant birds, giant lemurs, horned crocodiles, and other vertebrates larger in body size than 10 kg commonly date to the first millennium of the Common Era (CE) or earlier; few records date to the second millennium CE. Whereas megafaunal populations appear to have crashed almost simultaneously near the end of the first millennium CE, small populations can survive in remote pockets for centuries after precipitous species decline, perhaps longer. Examining the differences in the population dynamics of declining species and other factors can help to better identify the ultimate timing of extinction. Ever since Etienne de Flacourt traveled to Madagascar in the late 1600s, Malagasy stories of large-bodied wild animals have been recorded. Many include fantastic, clearly mythical creatures, but some provide anatomical or behavioral details which are consistent with legends or even direct observations of real, albeit potentially already extinct, species (including elephant birds, hippopotamuses, and some giant lemurs). In December 1989, at 06:00 hours, one of us (BZF) witnessed a large euplerid carnivoran locally known as fosabe (big fosa) or fosa jobijoby (blackish fosa) who had entered his field tent at Montagne d’Ambre. The animal was “twice the size and much darker than the common fossa” (Freed, 1996, p. 34). The individual was black and weighed approximately 20-25 kg. Freed wrote that the animal was well known to the local people and that “many local people also reported seeing it”. The animal fits paleontologists’ expectations for Cryptoprocta spelea, a large carnivoran known from the fossil record, believed to have been extinct for at least 1000 years. In June 2020, we recorded modern accounts of the big fosa. One of us (ESN) visited villages in four different sectors (Northwest, Northeast, East, and West) of Montagne d’Ambre National Park and the Forêt d’Ambre Special Reserve to examine potential regional differences and/or similarities in the stories of this animal, and whether such accounts include mythical elements, relevant anatomical information, and/or credible recent sightings. We also recorded stories of an Endangered extant animal, the aye-aye of the genus Daubentonia (also known locally as the kakahely). Ultimately, we believe this folklore provides clues that may help elucidate the geography of decline and possible late survival of an “extinct” megafaunal animal on Madagascar. 

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4. Evolutionary and phylogenetic insights from a nuclear genome sequence of the extinct, giant, “subfossil” koala lemur Megaladapis edwardsi

   https://doi.org/10.1073/pnas.2022117118  

   Marciniak, Stephanie ; Mughal, Mehreen R. ; Godfrey, Laurie R. ; Bankoff, Richard J. ; Randrianatoandro, Heritiana ; Crowley, Brooke E. ; Bergey, Christina M. ; Muldoon, Kathleen M. ; Randrianasy, Jeannot ; Raharivololona, Brigitte M. ; et al ( June 2021 , Proceedings of the National Academy of Sciences)

   No endemic Madagascar animal with body mass >10 kg survived a relatively recent wave of extinction on the island. From morphological and isotopic analyses of skeletal “subfossil” remains we can reconstruct some of the biology and behavioral ecology of giant lemurs (primates; up to ∼160 kg) and other extraordinary Malagasy megafauna that survived into the past millennium. Yet, much about the evolutionary biology of these now-extinct species remains unknown, along with persistent phylogenetic uncertainty in some cases. Thankfully, despite the challenges of DNA preservation in tropical and subtropical environments, technical advances have enabled the recovery of ancient DNA from some Malagasy subfossil specimens. Here, we present a nuclear genome sequence (∼2× coverage) for one of the largest extinct lemurs, the koala lemur Megaladapis edwardsi (∼85 kg). To support the testing of key phylogenetic and evolutionary hypotheses, we also generated high-coverage nuclear genomes for two extant lemurs, Eulemur rufifrons and Lepilemur mustelinus , and we aligned these sequences with previously published genomes for three other extant lemurs and 47 nonlemur vertebrates. Our phylogenetic results confirm that Megaladapis is most closely related to the extant Lemuridae (typified in our analysis by E. rufifrons ) to the exclusion of L. mustelinus , which contradicts morphology-based phylogenies. Our evolutionary analyses identified significant convergent evolution between M. edwardsi and an extant folivore (a colobine monkey) and an herbivore (horse) in genes encoding proteins that function in plant toxin biodegradation and nutrient absorption. These results suggest that koala lemurs were highly adapted to a leaf-based diet, which may also explain their convergent craniodental morphology with the small-bodied folivore Lepilemur . 

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5. What can hippopotamus isotopes tell us about past distributions of C 4 grassy biomes on Madagascar?

   https://doi.org/10.1002/ppp3.10402  

   Crowley, Brooke Erin ; Godfrey, Laurie Rohde ; Samonds, Karen Elizabeth ( July 2023 , PLANTS, PEOPLE, PLANET)

   Today, expansive C₄grassy biomes exist across central, western, and northern Madagascar. Some researchers have argued that the island's now‐extinct pygmy hippopotamuses belonged to a megaherbivore grazing guild that maintained these grasslands prior to human arrival. However, the chemistry of hippo bones indicates that C₄grasses were only a minor part of hippo diet. This, in turn, suggests that C₄grasses were present but not widespread when hippos were alive and that grasses expanded only after Malagasy people shifted from hunting and foraging to agropastoralism approximately 1000 years ago. These results have important implications for environmental reconstructions and biodiversity management.

   Extinct hippopotamuses (Hippopotamusspp.) were part of Madagascar's megaherbivore guild. Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopes in radiometrically dated bone collagen track spatial and temporal variation in diet and habitat. If hippos helped maintain C₄grassy biomes, then they should have regularly consumed C₄grasses, which have high δ¹³C values. However, if expansive C₄grassy biomes are anthropogenic, then forests would have been more extensive in the past, and hippos would have predominantly consumed C₃plants with low δ¹³C values. Nitrogen isotopes can clarify foraging habitat (moist or dry).

   We assessed δ¹³C and δ¹⁵N values for hippos from different ecoregions of Madagascar and compared these with data for extinct herbivorous lemurs from the same ecoregions. We further explored the effects of wet/dry transitions on isotopic trends for hippos from the central highlands and spiny thicket ecoregions.

   Carbon isotopes suggest (1) limited C₄consumption by hippos in the central highlands, dry deciduous forest, and succulent woodland ecoregions; and (2) moderate consumption of C₄resources in the spiny thicket. Nitrogen data indicate that hippos foraged in wetter habitats than sympatric lemurs in all regions.

   Malagasy hippos did not regularly graze C₄grasses in dry, open habitats, even in regions blanketed by C₄grassy biomes today. Malagasy grasses are adapted to grazing and fire, but these are likely ancient adaptations that accompanied grasses when they initially spread to Madagascar. C₄grassy biomes were spatially limited in extent in the past and only expanded after the Late Holocene introduction of domesticated ungulates.

    

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