Topic
Hexaprotodon
About: Hexaprotodon is a research topic. Over the lifetime, 39 publications have been published within this topic receiving 702 citations.
Papers
TL;DR: Large particles were excreted slower than the small particles in the ruminant of this study, the banteng, which confirms the hypothesis of a functional difference in selective particle retention between ruminating and non-ruminating foregut fermenters.
Abstract: Processing of ingesta particles plays a crucial role in the digestive physiology of herbivores In the ruminant forestomach different sized particles are stratified into a small and a large particle fraction and only the latter is regurgitated and remasticated to smaller, easier-to-digest particles In contrast, it has been suggested that in non-ruminating foregut fermenters, such as hippopotamuses, larger particles should be selectively excreted since they tend to be digested at a slower rate and hence can be considered intake-limiting bulk In our study we determined the mean retention time (MRT) of fluids and different sized particles (2 mm and 10 mm) in six pygmy hippos (Hexaprotodon liberiensis) and six banteng (Bos javanicus) on a diet of fresh grass at two intake levels We used cobalt ethylendiamintetraacetate (Co-EDTA) as fluid and chromium (Cr)-mordanted fibre (2 mm) and cerium (Ce)-mordanted fibre (10 mm) as particle markers, mixed in the food Average total tract MRT for fluid, small and large particles at the high intake level was 32, 76 and 73 h in pygmy hippos and 25, 56 and 60 h in banteng, and at the low intake level 39, 109, and 105 h in pygmy hippos and 22, 51 and 58 h in banteng, respectively In accordance with the prediction, large particles moved faster than, or as fast as the small particles, through the gut of pygmy hippos In contrast, large particles were excreted slower than the small particles in the ruminant of this study, the banteng Pygmy hippos had longer retention times than the banteng, which probably compensate for the less efficient particle size reduction Although the results were not as distinct as expected, most likely due to the fact that ingestive mastication of the larger particle marker could not be prevented, they confirm our hypothesis of a functional difference in selective particle retention between ruminating and non-ruminating foregut fermenters
57 citations
TL;DR: The pygmy hippopotamus, a non-ruminating foregut fermenter, has longer mean retention times than ruminants; however hippos do not achieve higher (fibre) digestibilities on comparable diets, which could be due to ineffective mastication, while wild cattle compared to hippos could have life-history consequences, such as a higher relative reproductive rate.
Abstract: The digestion of plant material in mammalian herbivores basically depends on the chemical and structural composition of the diet, the mean particle size to which the forage is processed, and the ingesta retention time. These different factors can be influenced by the animal, and they can presumably compensate for each other. The pygmy hippopotamus, a non-ruminating foregut fermenter, has longer mean retention times than ruminants; however hippos do not achieve higher (fibre) digestibilities on comparable diets, which could be due to ineffective mastication. We performed feeding trials with six pygmy hippos (Hexaprotodon liberiensis) and six banteng cattle (Bos javanicus) on a grass diet. As predicted, both species achieved similar dry matter, organic matter, crude protein and gross energy digestibilities. However, neutral and acid detergent fibre digestibility was lower in pygmy hippos. Apparently, in these species, fibre digestibility was more influenced by particle size, which was larger in pygmy hippos compared to banteng, than by retention time. In spite of their higher relative food intake, the banteng in this study did not have greater relative gut fills than the hippos. Ruminants traditionally appear intake-limited when compared to equids, because feed particles above a certain size cannot leave the rumen. But when compared to nonruminating foregut fermenters, rumination seems to free foregut fermenters from an intrinsic food intake limitation. The higher energy intakes and metabolic rates in wild cattle compared to hippos could have life-history consequences, such as a higher relative reproductive rate.
55 citations
TL;DR: In the Djurab Desert (Chad), the fossiliferous sectors of Kossom Bougoudi, Kolle and Koro Toro have yielded a great amount of fossil hippo remains aged between ca. 5 and 3 Ma as mentioned in this paper.
34 citations
TL;DR: A new small to medium-sized hippopotamus, Hexaprotodon lothagamensis, is described from the late Miocene of northern Kenya and appears to be less derived than the extant pygmy hippopotamia, H. (Choeropsis) liberiensis, which was previously considered to be a living fossil.
Abstract: A new small to medium-sized hippopotamus, Hexaprotodon lothagamensis is described from the late Miocene of northern Kenya. The material was recovered from Lothagam, a site southwest of Lake Turkana. This narrow-muzzled hippopotamus differs from other Hexaprotodon species in terms of its small size and shallow symphysis. The six incisors are arranged in a straight line across the front of the jaw and the lower canines are almost aligned with the cheek tooth row. H. lothagamensis compares more closely to an Arabian species, Hexaprotodon aff. H. sahabiensis from the late Miocene, than to any other African Hexaprotodon. The phylogeny of the Hippopotamidae is discussed and although the genera names are maintained, the genus Hexaprotodon is paraphyletic. Hexaprotodon lothagamensis appears to be less derived than the extant pygmy hippopotamus, H. (Choeropsis) liberiensis, which was previously considered to be a living fossil.
33 citations
TL;DR: A new species of Hippopotamidae based on abundant and well-preserved remains was discovered in the late Miocene levels of the Toros-Menalla fossiliferous area in the Djurab desert, Chad, central Africa as mentioned in this paper.
Abstract: A new species of Hippopotamidae based on abundant and well-preserved remains was discovered in the late Miocene levels of the Toros-Menalla fossiliferous area in the Djurab desert, Chad, central Africa. This hippopotamid is contemporaneous with Sahelanthropus tchadensis, a hominid from the same area, with an age of ca. 7.0 Ma. Hexaprotodon garyam sp. nov. is a large species with a robust, high mandibular symphysis. This feature is unknown in the Miocene East African hippos found at Lothagam, Kenya, but characterizes the Asian Hexaprotodon. This discovery enhances the heterogeneous character of the paraphyletic Hexaprotodon and indicates that the Hippopotamidae were a major component of the late Miocene environments in Central Africa as well as in East Africa.
33 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 4 |
| 2020 | 1 |
| 2019 | 1 |
| 2018 | 2 |
| 2016 | 1 |
| 2015 | 1 |