Morenelaphus
Fig 1. An artist’s interpretation of Morenelaphus sp. Painting used with permission from the artist Vitor Silva.
Taxonomy
Morenelaphus was a genus of large South American deer, traditionally divided into two species—M. brachyceros and M. lujanensis. The two species were not originally considered contemporaneous, with M. brachyceros being the older species, whilst M. lujanensis was, as the name indicates, from the Lujanian (0.8-0.11 Ma)(1). Newer evidence indicates, however, that the two species were contemporaneous, with M. brachyceros persisting into the Lujanian in at least one location (2). At the same time, although the species are said to be differentiated on grounds of antler-size and shape, much overlap exists. Accordingly, it has been proposed by Pêgo, F. B. (2014) that M. lujanensis should be considered a junior synonym of brachyceros, and the genus rendered monotypic.
Distribution
Morenelaphus was principally distributed in the southern regions of the continent, with findings from Argentina, Uruguay, Paraguay, and the Brazilian state of Pernambuco, the latter representing the most northerly remains (1). Its distribution correlates with a region called the Chacoense dominion—a savanna corridor, leading from Argentina into the northeast of Brazil (4).
Fig. 2. The estimated range of the genus Morenelaphus, based on fossil sites. Fossil site data was obtained from Rotti et al 2021. Samples of habitats in the region are also included.
Morphology and ecology
A comparatively large animal, Morenelaphus has been estimated at upwards of 118 kg, putting it near the upper range of Blastocerus dichotomus, the Marsh deer, currently the largest deer in South America (3). There has been discovered in Northeast Brazil a specimen of an indeterminate species, representing the largest Cervid ever found on the continent (3). At an estimated 209.7 kg, it was larger even than current estimates of Antifer, but whether the specimen belongs to that genus or to Morenelaphus is unknown. If the latter, it would dramatically increase the upper size limit of the animal. Unlike B. dichotomus, Morenelaphus had enormous, complex antlers. These were somewhat flattened, with a curving, somewhat “S”-like shape, and numerous branches (6).
Up until its extinction in the early Holocene, Morenelaphus was exceedingly abundant—the most common Cervid in the fossil record (4). Its diet appears to have been more grazing-focused than that of surviving South American Cervids, based on studies of dentition. Furthermore, the region to which it appears to have been endemic—the Chacoense dominion—was until the early Holocene a mosaic of grassland, savanna, and seasonally dry tropical forests, home also to other open-habitat species such as Equus neogeus (4). Indeed, fossils from the Santa Vitória Alloformation show that Morenelaphus co-existed with a broad swath of other megafauna, including the even larger deer Antifer, the camelid Hemiauchenia, ground-sloths Megatherium americanum and Mylodon darwini, toxodont Toxodon platensis and large proboscidean Notiomastodon, to name just a few. Predators from the formation—to which Morenelaphus was likely a prey-item—included the sabretooth Smilodon populator, canids Protocyon and Dusicyon, and bears of the genus Arctotherium. Jaguars (Panthera onca) also can be assumed as significant predators, occurring throughout the region, with the largest individuals being those inhabiting the open habitats that Morenelaphus preferred (8).
Fig 3. Antler of Morenelaphus brachyceros. Side view of specimen MLP 00-XI-1-19. Diagram adapted by Tristan Søbye Rapp from Pêgo, F. B. (2014).
Citations
1. Valli, A., (2018.) Late Pleistocene Deer in the Region of the National Park “Serra da Capivara” (Piauí, Brazil). Quaternary, 1(1). 4. DOI: https://doi.org/10.3390/quat1010004
2. Alcaraz, M.A. (2010). Sistemática de los cérvidos (Mammalia, Artiodactyla) del Pleistoceno de las Áreas Extraandinas de Argentina. Pdh. Faculty of Natural Sciences and Museum, National University of La Plata, Buenos Aires, Argentina.
3. Rotti, A., Vezzosi, R., Mothé, D. and Avilla, L. (2021). Rising from the ashes: The biggest South American deers (Cetartiodactyla: Cervidae) once roamed Northeast Brazil. Journal of South American Earth Sciences. 108. p. 103154. DOI: https://doi.org/10.1016/j.jsames.2021.103154
4. Rotti, A., Mothé, D., dos Santos Avilla, L. and Semprebon, G. (2018). Diet reconstruction for an extinct deer (Cervidae: Cetartiodactyla) from the Quaternary of South America. Palaeogeography, Palaeoclimatology, Palaeoecology. 497. pp. 244-252. DOI: https://doi.org/10.1016/j.palaeo.2018.02.026
5. Pêgo, F. B. (2014). Revisão taxonômica de Morenelaphus Carette, 1922 (Cetartiodactyla, Cervidae): uma abordagem morfológica dentária. Instituto de Biociências. Dissertation. 74 pp.
6. Forasiepi, A.M., Martinelli, A.G., Blanco, J. L. (2007). Bestiario Fosil Mamíferos del Pleistoceno de la Argentina. Editorial Albatros. First ed. Buenos Aires (2007), p. 192.
7. Lopes, R., Dillenburg, S., Savian, J. and Pereira, J. (2021). The Santa Vitória Alloformation: an update on a Pleistocene fossil-rich unit in Southern Brazil. Brazilian Journal of Geology. 51(1). DOI: 10.1590/2317-4889202120200065
8. Quigley, H., Foster, R., Petracca, L., Payan, E., Salom, R. & Harmsen, B. 2017. Panthera onca (errata version published in 2018). The IUCN Red List of Threatened Species 2017: e.T15953A123791436. http://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T15953A50658693.en
9. Faurby, S., Pedersen, R. Ø., Davis, M., Schowanek, S. D., Jarvie, S., Antonelli, A., & Svenning, J.C. (2020). PHYLACINE 1.2.1: An update to the Phylogenetic Atlas of Mammal Macroecology. doi:10.5281/zenodo.3690867