The family Desmatophocidae represents an early radiation of extinct pinnipeds that peaked in diversity during the middle Miocene. Although represented by abundant well-preserved fossils, the taxonomy and evolutionary relationships of this family remain poorly known. Late Miocene desmatophocids have been recorded, although none have been formally described, preventing a thorough appraisal of their decline and extinction. We report the discovery of a new species, Allodesmus demerei sp. nov., represented by a partial skeleton with cranium, mandibles, and axial skeleton, from the upper Miocene Montesano Formation of Washington, prompting reinterpretation of desmatophocid taxonomy, phylogeny, and extinction. Phylogenetic analysis (95 characters, 26 taxa) found strong support for monophyletic Desmatophocidae and Allodesmus. Desmatophocidae was found as sister to Phocidae with poor support. Allodesmus demerei was placed within the Allodesmus as the sister taxon to Allodesmus kernensis. The geochronologically young age (10.5–9.1 Mya) of Al. demerei establishes this species as the last of the desmatophocid seals. The middle Miocene peak in desmatophocid diversity coincides with the middle Miocene climatic optimum, suggesting that declining sea surface temperature played a role in their decline and extinction. Walruses diversified and increased in body size during the mid- to late Miocene as desmatophocids declined, suggesting some form of ecological displacement.
Robert W. Boessenecker and Morgan Churchill. 2018. The Last of the Desmatophocid Seals: A New Species of Allodesmus from the upper Miocene of Washington, USA, and a revision of the taxonomy of Desmatophocidae. Zoological Journal of the Linnean Society. zlx098. DOI: 10.1093/zoolinnean/zlx098
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
A new genus and species of fossil bat is described from New Zealand’s only pre-Pleistocene Cenozoic terrestrial fauna, the early Miocene St Bathans Fauna of Central Otago, South Island. Bayesian total evidence phylogenetic analysis places this new Southern Hemisphere taxon among the burrowing bats (mystacinids) of New Zealand and Australia, although its lower dentition also resembles Africa’s endemic sucker-footed bats (myzopodids). As the first new bat genus to be added to New Zealand’s fauna in more than 150 years, it provides new insight into the original diversity of chiropterans in Australasia. It also underscores the significant decline in morphological diversity that has taken place in the highly distinctive, semi-terrestrial bat family Mystacinidae since the Miocene. This bat was relatively large, with an estimated body mass of ~40 g, and its dentition suggests it had an omnivorous diet. Its striking dental autapomorphies, including development of a large hypocone, signal a shift of diet compared with other mystacinids, and may provide evidence of an adaptive radiation in feeding strategy in this group of noctilionoid bats.
An artist's impression of a New Zealand burrowing bat, Mystacina robusta, that went extinct last century. The new fossil find, Vulcanops jennyworthyae, that lived millions of years ago in New Zealand, is an ancient relative of burrowing or short-tailed bats.
Illustration: Gavin Mouldey.
Systematic palaeontology
Order Chiroptera Blumenbach, 1779
Suborder Yangochiroptera Van den Bussche & Hoofer, 2004
Superfamily Noctilionoidea Gray, 1821
Family Mystacinidae Dobson, 1875
Vulcanops jennyworthyae gen. et sp. nov.
Figure 1 Vulcanops jennyworthyae gen. et sp. nov., Bannockburn Formation, St Bathans, Central Otago, New Zealand. Lower dentition. CM 2013.18.790, holotype, left dentary fragment containing m2-3. (a) Buccal view; (b–b’) stereopair, occlusal view; (c) lingual view m2-3. NMNZ S.52078, paratype, right m1. (d–d’) Stereopair, oblique occlusal view; (e) buccal view; (f) occlusal view.
Stratigraphic and geographic distribution: Lower Miocene of Central Otago, New Zealand.
Etymology: From Vulcan, mythological god of fireand volcanoes (Roman), and ops, a suffix commonly used for bats; in reference to New Zealand’s tectonically active nature, as well as to the historic Vulcan Hotel, centre of the hamlet of St Bathans, from which the fauna takes its name. The species name honours Jennifer P. Worthy in recognition of her pivotal role in revealing the diversity of the St Bathans Fauna.
The fossil dig site at St Bathans in New Zealand where the fossilised remains of an extinct giant burrowing bat, Vulcanops jennyworthyae, were found.
photo: Trevor Worthy.
Washing of St Bathans sediments through sieves in Manuherikia River in New Zealand to collect fossil bones and teeth of an ancient burrowing bat.
photo: Vanesa De Pietri.
Suzanne J. Hand, Robin M. D. Beck, Michael Archer, Nancy B. Simmons, Gregg F. Gunnell, R. Paul Scofield, Alan J. D. Tennyson, Vanesa L. De Pietri, Steven W. Salisbury and Trevor H. Worthy. 2018. A New, Large-bodied Omnivorous Bat (Noctilionoidea: Mystacinidae) reveals Lost Morphological and Ecological Diversity since the Miocene in New Zealand. Scientific Reports. 8, Article number: 235. DOI: 10.1038/s41598-017-18403-w
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
Gomphotherium is a stem taxon of Elephantida that was widespread in Africa, Eurasia, and North America during the Miocene. However, the evolution of this genus is greatly debated because of morphological variation among the species of Gomphotherium. In the present work, we describe a cranium and accompanying material of Gomphotherium from the late middle Miocene Hujialiang Formation of Linxia Basin, China. The new material shows dental similarities to G. subtapiroideum from the middle Miocene of Europe; however, it displays some cranial, mandibular, and dental feature combinations that are distinct from the known species of Gomphotherium. Therefore, a new species, Gomphotherium tassyi, is established. We further study the phylogeny of Gomphotherium by cladistic analysis and recognize four groups. The most basal ‘G. annectens group’ is a paraphyletic group that includes G. annectens, G. cooperi, G. sylvaticum, and G. hannibali. The African taxa, G. libycum and G. pygmaeus, constitute a monophyletic group that has not been named. The ‘G. angustidens group’ is a monophyletic group that includes G. inopinatum, G. mongoliense, G. connexum, and G. angustidens. In addition, the ‘derived Gomphotherium group,’ which includes G. subtapiroideum, G. tassyi, G. wimani, G. browni, G. productum, and G. steinheimense, was widely distributed in Eurasia and North America during the middle and late Miocene.
Shi-Qi Wang, Yu Li, Jaroon Duangkrayom, Xiang-Wen Yang, Wen He and Shan-Qin Chen. 2017. A New Species of Gomphotherium (Proboscidea, Mammalia) from China and the Evolution of Gomphotherium in Eurasia. Journal of Vertebrate Paleontology.37(3); DOI: 10.1080/02724634.2017.1318284
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
Otters (subfamily Lutrinae) are semi-aquatic predators in the family Mustelidae. Modern otters have a worldwide distribution but their fossil record is poor, often consisting of fragmentary jaws and teeth. Multiple lineages have developed bunodont dentitions with enlargements of molars, usually for cracking molluscs or other hard foods. Some lineages have evolved badger-like teeth and, as a result, were often confused with melines (Old World badger clade). Siamogale thailandica Ginsburg, Invagat, & Tassy, 1983 from the middle Miocene basin of Mae Moh in northern Thailand is one such species, whose fragmentary dental remains have thus far impeded our understanding. A new species of fossil otter, Siamogale melilutra sp. nov., represented by a nearly complete cranium, mandible and partial skeletons of at least three individuals, was recovered from the latest Miocene (∼6.2 Ma) lignite beds of the Shuitangba Site in north-eastern Yunnan Province, south-western China. Computed tomography (CT) restoration of the crushed skull reveals a combination of otter-like and badger-like cranial and dental characteristics. The new species belongs to the Lutrinae because of its possession of a large infraorbital canal and ventral expansion of the mastoid process, among other traits. A distally expanded M1, however, gives a badger-like appearance. In overall morphology the Shuitangba otter is closest to Siamogale thailandica. A previously described jaw (‘Lutra’ aonychoides) from the early Pliocene of the Yushe Basin in north China is also here referred to S. melilutra. No previous attempt has been made to provide a global phylogenetic framework for otters. We present the first combined morphological and molecular (nuclear and mitochondrial DNAs) character matrices of five extant (Pteronura, Lontra, Enhydra, Aonyx, Lutra) and eight extinct genera (Tyrrhenolutra, Paralutra, Paludolutra, Enhydritherium, Siamogale, Vishnuonyx, Sivaonyx, Enhydriodon) to better understand the evolution of bunodont otters. Parsimony and Bayesian analyses consistently recover an eastern Asian clade that includes forms from Shuitangba, Yushe and Mae Moh, all of which are referred to Siamogale.
Keywords: Miocene, fossil otter, lutrine, phylogeny, China, Southeast Asia
Artist's reconstruction of two individuals ofSiamogale melilutra sp. nov., one of them feeding on a freshwater clam. The tapir in the background is Tapirus yunnanensis (Ji et al. 2015). Aquatic plants include water chestnut (Typha) and fox nut (Euryale) (Huang et al. 2015), and the low shrub in foreground is Sichuan peppercorn (Zanthoxylum).
Type species: Siamogale thailandica Ginsburg, Ingavat & Tassy, 1983.
Included species: Siamogale thailandica Ginsburg, Ingavat & Tassy, 1983 and Siamogale melilutra sp. nov.
Emended diagnosis:
Siamogale has typical lutrine cranial and dental morphologies: a large infraorbital canal, presence of antorbital fossa, uninflated bulla, robust and protruding mastoid process, mastoid process separated by a broad shelf from the paroccipital process, postglenoid foramen positioned anteriorly to the auditory meatus, inion positioned anteriorly relative to the lambdoid crest, stylomastoid foramen separated by a bony ridge from the tympanohyal-bulla connection, masseter muscle attachment area ventrally expanded to beyond the ventral rim of the masseteric fossa, parallel zygomatic arches, shortened angular process, premolars with surrounding cingulum, shortening of P4 metastylar blade, presence of a notch between talonid and trigonid of m1, and widening of m1 talonid. Siamogale differs from Paralutra jaegeri by the presence of a distal ridge of m1 metaconid connected to the entoconid crest, M1 cuspule distal to metacone, and absence of P4 metastylar notch. Siamogale differs from Paludolutra, Tyrrhenolutra and Enhydritherium in having a crestiform protocone, lack of hypocone and presence of parastyle on P4, a distolingually expanded M1 talon, and metaconule placed distally to the metacone.
Figure 2. Cranium of Siamogale melilutra sp. nov., ZT-10-03-064b, holotype from Shuitangba. A, right lateral, and B, dorsal views.
Figure 1. Location of Shuitangba (late Miocene) in the Zhaotong Basin, Yunnan Province, the Yushe Basin (Pliocene), Shanxi Province, China, and the Mae Moh Basin (middle Miocene), Lampang Province, Thailand.
Siamogale sp. nov. Jablonski, Su, Flynn, Ji, Deng, Kelley, Zhang, Yin, You, & Yang: table 1, fig. 3D.
Diagnosis:Siamogale melilutra is distinct from S. thailandica in its large size, more posteriorly reclined mandibular ascending ramus, a continuous P4 protocone crest extending distally to the metastyle (in contrast to a more cuspidate P4 protocone in S. thailandica), a relatively less distally expanded M1 lingual cingulum, a more shortened m1, and an m1 metaconid ridge being differentiated into a discrete metastylid.
Figure 4. Digitally restored cranium of Siamogale melilutra sp. nov., ZT-10-03-064b, holotype from Shuitangba, plus a right mandible, IVPP V 23271 (in C only). A, ventral, B, dorsal, C, right lateral, D, anterior oblique, E, posterior and F, anterior views.
Etymology: mēlēs and melis (feminine), Latin, badger; lutra (feminine), Latin, otter; a reference to the mixture of typically lutrine and meline cranial and dental morphology in this species.
Figure 12. Artist's reconstruction of two individuals ofSiamogale melilutra sp. nov., one of them feeding on a freshwater clam. The tapir in the background is Tapirus yunnanensis (Ji et al. 2015). Aquatic plants include water chestnut (Typha) and fox nut (Euryale) (Huang et al. 2015), and the low shrub in foreground is Sichuan peppercorn (Zanthoxylum).
Xiaoming Wang, Camille Grohé, Denise F. Su, Stuart C. White, Xueping Ji, Jay Kelley, Youshan You and Xin Yang. 2017. A New Otter of Giant Size, Siamogale melilutra sp. nov. (Lutrinae: Mustelidae: Carnivora), from the latest Miocene Shuitangba Site in north-eastern Yunnan, south-western China, and A Total-Evidence Phylogeny of Lutrines.
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
Many odontocete groups have developed enlarged facial crests, although these crests differ in topography, composition and function. The most elaborate crests occur in the South Asian river dolphin (Platanista gangetica), in which they rise dorsally as delicate, pneumatized wings anterior of the facial bones. Their position wrapping around the melon suggests their involvement in sound propagation for echolocation. To better understand the origin of crests in this lineage, we examined facial crests among fossil and living Platanistoidea, including a new taxon, Dilophodelphis fordycei, nov. gen. and sp., described herein, from the Early Miocene Astoria Formation of Oregon, USA. We measured the physical extent and thickness of platanistoid crests, categorized their relative position and used computed tomography scans to examine their internal morphology and relative bone density. Integrating these traits in a phylogenetic context, we determined that the onset of crest elaboration or enlargement and the evolution of crest pneumatization among the platanistoids were separate events, with crest enlargement beginning in the Oligocene. However, we find no evidence for pneumatization until possibly the Early Miocene, although certainly by the Middle Miocene. Such an evolutionary context, including data from the fossil record, should inform modelling efforts that seek to understand the diversity of sound generation morphology in Odontoceti.
KEYWORDS: cetacean, Platanistoidea, river dolphins, Miocene, pneumatization, computed tomography
Systematic palaeontology
Cetacea Brisson, 1762
Odontoceti Flower, 1867 sensu Fordyce and Muizon, 2001
Platanistoidea sensu Boersma and Pyenson 2016
Platanistidae Gray, 1846 sensu Boersma and Pyenson 2016
Dilophodelphis, gen. nov.
Type and only included species. Dilophodelphis fordycei, sp. nov.
Etymology. From the Greek words di (double), lophos (crest) and delphis (dolphin), referring to the enlarged supraorbital crests on the dorsal surface of the skull, resembling twin mountain crests. This construction also evokes the dinosaur Dilophosaurus wetherilli Welles 1954, a double-crested theropod recovered from Early Jurassic sequences of the Kayenta Formation in Arizona, USA.
Dilophodelphis fordycei, sp. nov.
Figure 1. Skull of Dilophodelphis (USNM 214911) in dorsal view. (a) Illustrated skull with low opacity mask, interpretive line art and labels for skull elements. Dotted lines indicate uncertainty of sutures, and dashed lines highlight fossae. Hatched pattern indicates areas where sediment is obscuring the fossil. (b) Photograph of skull in dorsal view, photography by James Di Loreto, Smithsonian Institution. fr., frontals; max., maxilla; n., nasal; pmx., premaxilla; pmx. sac fossa, premaxillary sac fossa.
Figure 2. Skull of Dilophodelphis (USNM 214911) in ventral view. (a) Illustrated skull with low opacity mask, interpretive line art and labels for skull elements. Dotted lines indicate uncertainty of sutures, and dashed lines highlight fossae. Hatched pattern indicates areas where sediment is obscuring the fossil. (b) Photograph of skull in ventral view, photography by James Di Loreto, Smithsonian Institution. fr., frontal; max., maxilla; p., pterygoid; v., vomer.
The endangered South Asian river dolphin, Platanista gangetica (middle), swimming alongside two of its fossil relatives: the longirostral Pomatodelphis inaequalis (bottom) and the new species Dilophodelphis fordycei (top). None of the species lived together at the same time. Glow-throughs to the skulls highlight the diversity in supraorbital crest shape and size among the members of this family.
Figure 3. Skull of Dilophodelphis (USNM 214911) in right and left lateral views. (a) Illustrated skull in right lateral view and (b) left lateral view with low opacity mask, interpretive line art and labels for skull elements. Dotted lines indicate uncertainty of sutures, and dashed lines highlight fossae. Hatched pattern indicates areas where sediment is obscuring the fossil. (c) Photograph of skull in right lateral view and (d) left lateral view, photography by James Di Loreto, Smithsonian Institution. exocc., exoccipital; m., maxilla; par., parietal; p., pterygoid; sq., squamosal; temp. fossa, temporal fossa; zyg. process, zygomatic process.
Etymology: The species epithet honours Prof. R. Ewan Fordyce, FRSNZ, native New Zealander and prominent vertebrate palaeontologist. The epithet recognizes his extensive and long-lasting contributions to the field of marine mammal palaeontology, including his commitment to mentoring future scientists, especially in shaping the career paths of the authors herein. The epithet also honours his long-standing interest in the fossil marine mammal record of Oregon, which has yielded pivotal specimens for over a century, including Simocetus rayiFordyce 2002, which he described.
Alexandra T. Boersma, Matthew R. McCurry and Nicholas D. Pyenson. 2017. A New Fossil Dolphin Dilophodelphis fordycei Provides Insight Into the Evolution of Supraorbital Crests in Platanistoidea (Mammalia, Cetacea). Royal Society Open Science. DOI: 10.1098/rsos.170022
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
