SIRENIA FOSSILS FROM QOM FORMATION (BURDIGALIAN) OF THE KABUDAR AHANG AREA, NORTHWEST IRAN

Fossil remains of sirenians (Mammalia; Dugongidae) are reported from the late early Miocene (Burdigalian) Qom Formation near the town of Shirin Su, northwest Kabudar Ahang region, west of Tehran, Iran. The fossils consist of partial postcranial skeletons preserved mostly as natural molds in limestone. In the absence of skulls or other diagnostic elements, it is not evident which dugongid subfamily these specimens represent: Halitheriinae or Dugonginae. Both subfamilies were present in contemporaneous Western Tethys (Mediterranean) deposits, but so far only dugongines have been found in Neogene rocks of Eastern Tethys. Since the Iranian deposits are located between these two parts of the former Tethys Seaway, it will be interesting to see which group(s) the Iranian sirenians prove to represent, once their taxonomic identity has been determined through future discoveries

Iterative Evolution of Sympatric Seacow (Dugongidae, Sirenia) Assemblages during the Past ∼26 Million Years

Extant sirenians show allopatric distributions throughout most of their range. However, their fossil record shows evidence of multispecies communities throughout most of the past ∼26 million years, in different oceanic basins. Morphological differences among co-occurring sirenian taxa suggest that resource partitioning played a role in structuring these communities. We examined body size and ecomorphological differences (e.g., rostral deflection and tusk morphology) among sirenian assemblages from the late Oligocene of Florida, early Miocene of India and early Pliocene of Mexico; each with three species of the family Dugongidae. Although overlapping in several ecomorphological traits, each assemblage showed at least one dominant trait in which coexisting species differed. Fossil sirenian occurrences occasionally are monotypic, but the assemblages analyzed herein show iterative evolution of multispecies communities, a phenomenon unparalleled in extant sirenian ecology. As primary consumers of seagrasses, these communities likely had a strong impact on past seagrass ecology and diversity, although the sparse fossil record of seagrasses limits direct comparisons. Nonetheless, our results provide robust support for previous suggestions that some sirenians in these extinct assemblages served as keystone species, controlling the dominance of climax seagrass species, permitting more taxonomically diverse seagrass beds (and sirenian communities) than many of those observed today

The Magnitude of Global Marine Species Diversity

Background: The question of how many marine species exist is important because it provides a metric for how much we do and do not know about life in the oceans. We have compiled the first register of the marine species of the world and used this baseline to estimate how many more species, partitioned among all major eukaryotic groups, may be discovered. Results: There are ∼226,000 eukaryotic marine species described. More species were described in the past decade (∼20,000) than in any previous one. The number of authors describing new species has been increasing at a faster rate than the number of new species described in the past six decades. We report that there are ∼170,000 synonyms, that 58,000–72,000 species are collected but not yet described, and that 482,000–741,000 more species have yet to be sampled. Molecular methods may add tens of thousands of cryptic species. Thus, there may be 0.7–1.0 million marine species. Past rates of description of new species indicate there may be 0.5 ± 0.2 million marine species. On average 37% (median 31%) of species in over 100 recent field studies around the world might be new to science. Conclusions: Currently, between one-third and two-thirds of marine species may be undescribed, and previous estimates of there being well over one million marine species appear highly unlikely. More species than ever before are being described annually by an increasing number of authors. If the current trend continues, most species will be discovered this century

Manati And Trichechus exunguis Mammalia Sirenia Proposal To Place These Names On The Official Indexes Of Rejected And Invalid Names In Zoology

Volume: 38Start Page: 130End Page: 13

Halianassa studeri Von Meyer 1838 Mammalia Sirenia Proposed Designation Of A Neotype And Proposed Conservation Of Halitherium Kaup 1838 By Designation Of A Type Species

Volume: 44Start Page: 122End Page: 13

Bibliography and index of the Sirenia and Desmostylia

Includes index

A Phylogenetic Analysis of the Sirenia

Volume: 29Start Page: 177End Page: 18

Figure 5 in The anatomy of Odobenocetops (Delphinoidea, Mammalia), the walrus-like dolphin from the Pliocene of Peru and its palaeobiological implications

Figure 5. Reconstruction of the dorsal view of the rostrum of Odobenocetops leptodon. Abbreviations: Fps, fossa for the premaxillary sac; Fr, frontal; Mx, maxilla; NaF, narial fossa; Pmx, premaxilla; Sb, supplementary bone.Published as part of <i>Muizon, Christian de & Domning, Daryl P., 2002, The anatomy of Odobenocetops (Delphinoidea, Mammalia), the walrus-like dolphin from the Pliocene of Peru and its palaeobiological implications, pp. 423-452 in Zoological Journal of the Linnean Society 134 (4)</i> on page 430, DOI: 10.1046/j.1096-3642.2002.00015.x, <a href="http://zenodo.org/record/10114644">http://zenodo.org/record/10114644</a&gt

Odobenocetops PERUVIANUS MUIZON 1993

<i>ODOBENOCETOPS</i> MUIZON, 1993 <p> <i>Type species</i>: <i>Odobenocetops peruvianus</i> Muizon, 1993. <i>Emended diagnosis</i>: delphinoid cetacean which does not possess the elongated rostrum present in all other cetaceans. The rostrum is short, rounded, and blunt; it is formed by the premaxillae which are greatly enlarged and have large, asymmetrical ventral alveolar sheaths holding sexually dimorphic tusks. The right tusk of the male is large and can reach one metre or more in length. It is cylindrical and its section is mediolaterally compressed (the long axis measures <i>c</i>. 4–5 cm). The left tusk of the male was only between 20 and 25 cm long, of which a few cm were erupted. Its section is also mediolaterally compressed. Both tusks are straight. In the female, the right tusk is only slightly larger than the left and both protruded only a few cm from the gum. Premaxillary sheaths and tusks form an angle of approximately 60–70° with the dorsal plane of the skull. The bony nares have been displaced anteriorly and are anteroposteriorly elongated. The palate is very deep and arched, and its anterior border (which is formed by the anterior edges of the alveolar sheaths) is U- to V-shaped. On the palate the vomer is very large and the premaxillae and the pterygoids are in contact with it. The maxillae have been excluded from the palate and relegated to a small triangular area on the lateral side of the rostrum and an elongated strip on the dorsal face of the skull. The postorbital processes are large and lateral to the posterior end of the nares. The orbits face anterolaterally and dorsally. The portions of the frontals and maxillae which cover the temporal fossae in the other odontocetes have been reduced and narrowed in such a way that the temporal fossae are opened dorsally. Ventrally, the crest of the hamular processe of the pterygoid is strong and rounded and the choanae are very wide. The basioccipital is extremely wide and long. The glenoid cavity of the squamosal is an anteroposteriorly elongated groove. The occipital condyles are very salient and more convex than in any other Pliocene or living cetacean.</p>Published as part of <i>Muizon, Christian de & Domning, Daryl P., 2002, The anatomy of Odobenocetops (Delphinoidea, Mammalia), the walrus-like dolphin from the Pliocene of Peru and its palaeobiological implications, pp. 423-452 in Zoological Journal of the Linnean Society 134 (4)</i> on page 424, DOI: 10.1046/j.1096-3642.2002.00015.x, <a href="http://zenodo.org/record/4687167">http://zenodo.org/record/4687167</a&gt

A new Dugonginae sirenian from the early Miocene of India

We redescribe the holotype skull of "Metaxytherium" kachchhense Bajpai, Singh, and Singh, 1987, and erect for it the new genus Bharatisiren. This skull is the best-preserved specimen of a fossil sirenian so far reported from the Indian Ocean region, and is also the first fossil from that region that is unequivocally referable to the subfamily Dugonginae. Bharatisiren kachchhensis (new combination) is related cladistically to other members of the subfamily as follows: (Crenatosiren (Dugong (Bharatisiren (other dugongines)))). The Dugonginae probably arose in the Caribbean-western Atlantic region, and underwent an adaptive radiation and pantropical dispersal in the Late Oligocene and Early Miocene