TY - JOUR
T1 - Evolving between land and water
T2 - Key questions on the emergence and history of the hippopotamidae (hippopotamoidea, cetancodonta, cetartiodactyla)
AU - Boisserie, Jean Renaud
AU - Fisher, Rebecca E.
AU - Lihoreau, Fabrice
AU - Weston, Eleanor M.
PY - 2011/8
Y1 - 2011/8
N2 - The fossil record of the Hippopotamidae can shed light on three major issues in mammalian evolution. First, as the Hippopotamidae are the extant sister group of Cetacea, gaining a better understanding of the origin of the Hippopotamidae and of their Paleogene ancestors will be instrumental in clarifying phylogenetic relationships within Cetartiodactyla. Unfortunately, the data relevant to hippopotamid origins have generally been ignored in phylogenetic analyses of cetartiodactyls. In order to obtain better resolution, future analyses should consider hypotheses of hippopotamid Paleogene relationships. Notably, an emergence of the Hippopotamidae from within anthracotheriids has received growing support, leading to reconciliation between genetic and morphological evidence for the clade Cetancodonta (Hippopotamidae + Cetacea). Secondly, full account needs to be taken of the Hippopotamidae when studying the impact of environmental change on faunal evolution. This group of semi-aquatic large herbivores has a clear and distinct ecological role and a diverse and abundant fossil record, particularly in the African Neogene. We examine three major phases of hippopotamid evolution, namely the sudden appearance of hippopotamines in the late Miocene (the "Hippopotamine Event"), the subsequent rampant endemism in African basins, and the Pleistocene expansion of Hippopotamus. Each may have been influenced by multiple factors, including: late Miocene grass expansion, African hydrographical network disruption, and a unique set of adaptations that allowed Hippopotamus to respond efficiently to early Pleistocene environmental change. Thirdly, the fossil record of the Hippopotamidae documents the independent emergence of adaptive character complexes in relation to semiaquatic habits and in response to insular isolation. The semiaquatic specializations of fossil hippopotamids are particularly useful in interpreting the functional morphology and ecology of other, extinct groups of large semiaquatic herbivores. Hippopotamids can also serve as models to elucidate the evolutionary dynamics of island mammals.
AB - The fossil record of the Hippopotamidae can shed light on three major issues in mammalian evolution. First, as the Hippopotamidae are the extant sister group of Cetacea, gaining a better understanding of the origin of the Hippopotamidae and of their Paleogene ancestors will be instrumental in clarifying phylogenetic relationships within Cetartiodactyla. Unfortunately, the data relevant to hippopotamid origins have generally been ignored in phylogenetic analyses of cetartiodactyls. In order to obtain better resolution, future analyses should consider hypotheses of hippopotamid Paleogene relationships. Notably, an emergence of the Hippopotamidae from within anthracotheriids has received growing support, leading to reconciliation between genetic and morphological evidence for the clade Cetancodonta (Hippopotamidae + Cetacea). Secondly, full account needs to be taken of the Hippopotamidae when studying the impact of environmental change on faunal evolution. This group of semi-aquatic large herbivores has a clear and distinct ecological role and a diverse and abundant fossil record, particularly in the African Neogene. We examine three major phases of hippopotamid evolution, namely the sudden appearance of hippopotamines in the late Miocene (the "Hippopotamine Event"), the subsequent rampant endemism in African basins, and the Pleistocene expansion of Hippopotamus. Each may have been influenced by multiple factors, including: late Miocene grass expansion, African hydrographical network disruption, and a unique set of adaptations that allowed Hippopotamus to respond efficiently to early Pleistocene environmental change. Thirdly, the fossil record of the Hippopotamidae documents the independent emergence of adaptive character complexes in relation to semiaquatic habits and in response to insular isolation. The semiaquatic specializations of fossil hippopotamids are particularly useful in interpreting the functional morphology and ecology of other, extinct groups of large semiaquatic herbivores. Hippopotamids can also serve as models to elucidate the evolutionary dynamics of island mammals.
KW - Africa
KW - Artiodactyl paraphyly
KW - Biogeography
KW - Environmental changes
KW - Insular evolution
KW - Neogene
KW - Parallelism
KW - Phylogeny
KW - Semiaquatic adaptations
UR - http://www.scopus.com/inward/record.url?scp=79960434258&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79960434258&partnerID=8YFLogxK
U2 - 10.1111/j.1469-185X.2010.00162.x
DO - 10.1111/j.1469-185X.2010.00162.x
M3 - Article
C2 - 20946539
AN - SCOPUS:79960434258
VL - 86
SP - 601
EP - 625
JO - Biological Reviews of the Cambridge Philosophical Society
JF - Biological Reviews of the Cambridge Philosophical Society
SN - 0006-3231
IS - 3
ER -