The earliest known fully quadrupedal sirenian

  title={The earliest known fully quadrupedal sirenian},
  author={Daryl Domning},
  • D. Domning
  • Published 11 October 2001
  • Geography
  • Nature
Modern seacows (manatees and dugongs; Mammalia, Sirenia) are completely aquatic, with flipperlike forelimbs and no hindlimbs. Here I describe Eocene fossils from Jamaica that represent nearly the entire skeleton of a new genus and species of sirenian—the most primitive for which extensive postcranial remains are known. This animal was fully capable of locomotion on land, with four well-developed legs, a multivertebral sacrum, and a strong sacroiliac articulation that could support the weight of… 
The Hind Limbs of Sobrarbesiren cardieli (Eocene, Northeastern Spain) and New Insights into the Locomotion Capabilities of the Quadrupedal Sirenians
The hind limb bones of Sobrarbesiren are described in detail, analyzing their functional morphology and comparing them with other basal sirenians and cetaceans, and with related terrestrial mammals such as proboscideans and hyracoids, and confirm that the microanatomical changes precede the external morphological changes in such ecological transitions.
Endocranial Morphology of a Middle Miocene South American Dugongid and the Neurosensorial Evolution of Sirenians
Ancestral character state reconstruction suggests that, despite an overall slight increase in the degree of encephalization of sirenians, except for the extant Dugong dugon, other analyzed taxa present values below 0.5.
Sirenia (Dugongs and Manatees)
Sirenia are an order of large, aquatic, plant-eating, mostly tropical placental mammals that includes the modern seacows and manatees and their extinct relatives that makes up a group known as Tethytheria, after their likely origin along the shores of the ancient Tethys Seaway in the Old World.
First adequately-known quadrupedal sirenian from Eurasia (Eocene, Bay of Biscay, Huesca, northeastern Spain)
Sirenians are the only extant herbivorous mammals fully adapted to an aquatic lifestyle and Sobrarbesiren is recovered as the sister taxon of Dugongidae and represents a transitional stage of adaptation to aquatic life between the amphibious quadrupedAL prorastomids and the aquatic quadrupedal protosirenids.
Evolution of Sirenian Pachyosteosclerosis, a Model-case for the Study of Bone Structure in Aquatic Tetrapods
To document how these features differentiated during sirenian evolution, the ribs of 15 species, from the most basal form (Pezosiren portelli) up to extant taxa, were studied and compared to those of other mammalian species from both morphometric and histological points of view.
Cranial Remain from Tunisia Provides New Clues for the Origin and Evolution of Sirenia (Mammalia, Afrotheria) in Africa
X-ray microtomography is used to investigate a newly discovered sirenian petrosal from the Eocene of Tunisia, which represents the oldest occurrence of sirenians in Africa and supports their African origin.
Evolutionary Transitions in the Fossil Record of Terrestrial Hoofed Mammals
  • D. Prothero
  • Geography
    Evolution: Education and Outreach
  • 2009
In the past few decades, many new discoveries have provided numerous transitional fossils that show the evolution of hoofed mammals from their primitive ancestors. We can now document the origin of
The locomotion of extinct secondarily aquatic tetrapods
  • Susana GutarraI. Rahman
  • Biology, Environmental Science
    Biological reviews of the Cambridge Philosophical Society
  • 2021
An overview of the latest research on the locomotion of extinct secondarily aquatic tetrapods, with a focus on amniotes, highlighting the state‐of‐the‐art experimental approaches used in this field and discussing the suitability of these techniques for exploring different aspects of locomotory adaptation.
The most northerly record of the sirenian Protosiren and the possible polyphyletic evolution of manatees and dugongs
Newly discovered remains of the early Middle Eocene (Lutetian) sirenian Protosiren (Protosirenidae) in shark tooth rich conglomerates from a coastal delta environment northwest of the European


Fossil sirenia of the west Atlantic and Caribbean region. V. The most primitive known sirenian, Prorastomus sirenoides Owen, 1855
Although Prorastomus appears to have some autapomorphies that exclude it from the direct ancestry of other sirenians, it is the best available approximation to a structural ancestor of the Sirenia, and is more appropriate than any Recent species as a representative of the order in analyzing the relationships of sirenian to other mammals.
North American Eocene Sea Cows (Mammalia: Sirenia)
Domning, Daryl P., Gary S. Morgan, and Clayton E. Ray. North American Eocene Sea Cows (Mammalia: Sirenia). Smithsonian Contributions to Paleobiology, number 52, 69 pages, 34 figures, 4 tables,
The readaptation of Eocene sirenians to life in water
Eocene sirenians and cetaceans simultaneously and independently evolved similar morphological adaptations to aquatic life. These included increased flexibility in the sacral region, reduction and
Functional significance of bone ballastin in the evolution of buoyancy control strategies by aquatic tetrapods
Biomechanical considerations lead to the prediction that a new marine tetrapod clade will typically evolve bone ballast as part of its adaptation to life in water.
It is suggested that selection for maintenance of trim and maximization of turning moments of the flippers may help account, respectively, for hindlimb loss and shortening of the neck in both sirenians and cetaceans.
Phylogenetic assessment of molecular and morphological data for eutherian mammals.
The interordinal relationships of eutherian (placental) mammals were evaluated by a phylogenetic analysis of four published data sets (three sequences and one morphological). The nature and degree of
Transitions from Drag-based to Lift-based Propulsion in Mammalian Swimming
  • F. Fish
  • Environmental Science, Biology
  • 1996
Examination of modern analogs to transitional swimming stages suggests that only slight modification to the neuromotor pattern used for terrestrial locomotion is required to allow for a change to lift-based propulsion.