Fossil Equidae in the Linxia Basin with Biostratigraphic and Paleozoogeographic Significance

The Linxia Basin is characterized by an abundance of Cenozoic sediments,that contain exceptionally rich fossil resources.Equids are abundant in the Linxia Basin,the fossil record of equids in this region including 16 species that represent 10 genera.In comparison to other classic late Cenozoic areas in China,the Linxia Basin stands out,because the fauna and chronological data accompanying Linxia equids render them remarkably useful for biostratigraphy.The anchitheriines in the region,such as Anchitherium and Sinohippus,represent early equids that appeared in the late stages of the middle and late Miocene,respectively.Among the equines,most species of Chinese hipparions have been identified in the Linxia Basin and some species of the genera Hipparion and Hippotherium have FAD records for China.Furthermore,Equus eisenmannae is one of the earliest known species of Equus in the Old World and is well-represented at the Longdan locality.Some species with precise geohistorical distributions can serve as standards for high-resolution chronological units within this framework.Located at the eastern margin of the Tibetan Plateau and subject to considerable uplift,the Linxia Basin has served as a biogeographic transition area for equids throughout the late Cenozoic.

Global evolution of Equidae and Gomphotheriidae from South America

The contemporary South American mammalian communities were determined by the emergence of the Isthmus of Panama and by the profound climatic oscillations during the Pleistocene.Horses and gomphotheres were 2 very conspicuous groups of immigrant mammals from North America that arrived in South America during the Pleistocene.The present study compiles updated data on the phylogeny,systematics and ecology of both groups in South America.The horses in South America are represented by 2 genera,Hippidion and Equus,as are the gomphotheres,represented by Cuvieronius and Stegomastodon.Both genera of horses include small(Hippidi­on devillei,H.saldiasi,E.andium and E.insulatus)and large forms(Equus neogeus and H.principale),which dispersed into South America using 2 different routes.The possible model for this dispersion indicates that the small forms used the Andes corridor,while larger horses dispersed through the eastern route and through some coastal areas.In the case of gomphotheres,Cuvieronius and Stegomastodon reached South America in 2 inde­pendent dispersal events,and Cuvieronius dispersed across the Andean corridor,while large Stegomastodon spread along the eastern route.Horses and gomphotheres present values ofδ^(13)C from woodlands to C4 grass­lands.Hippidion present lower values ofδ^(13)C than Equus in the late Pleistocene,whereas the gomphotheres di­verge from value ofδ^(18)O,reflecting that Cuvieronius inhabited the Andean corridor and Stegomastodon dis­persed through eastern plains.The gomphothere and horse species recorded in South America became extinct around the time that humans arrived.

Seroprevalence of <i>Clostridium tetani</i>in Donkeys in Kaduna State, Nigeria

Tetanus is an acute non-contagious and infectious disease caused by Clostridium tetani exotoxins that affect many animal species and humans. It is associated with high mortality rate, ranging from 58% to 80% in Equidae. This study investigated the seroprevalence of C. tetani antibodies in donkeys in Kaduna State. A total of 384 donkeys were sampled from the study area, 5 ml of blood was collected aseptically from the jugular vein and sera was harvested and tested for tetanus using ELISA kits. A seroprevalence of C. tetani of 295/384 (76.8%) was recorded. Male donkeys had a higher sero-prevalence (89.9%) than female (64.1%), young donkeys had 78.5% compared to 75.7% for adults;donkeys with wounds had a seroprevalence of 92.1% while those without wounds (42.4%). Donkeys from free range had a higher seroprevalence of 88.0%. Donkeys with BCS of 1 and 2 had 87.8% being the highest value, based on breeds, the Fari and Idabari had the higher seroprevalence (85.7% and 87.2% respectively), It was concluded that the donkeys in the Northern Kaduna had a high seroprevalence to C. tetani and also sex, age, breeds and presence of wounds were the main risk factors to C. tetani infection in donkeys and it was recommended that the use of donkeys in production of tetanus antitoxins and toxoid should be investigated.