Pecoran Ruminants Research Articles

The postcranial skeleton of Amphimoschus Bourgeois, 1873 (Cetartiodactyla, Ruminantia, Pecora) sheds light on its phylogeny and the evolution of the clade Cervoidea

Here we present the first description of the postcranial skeleton of Amphimoschus, an enigmatic hornless ruminant known from the late Early to the late Middle Miocene of Eurasia (c. 17.5–13.8 Ma). This new fossil material that includes several elements of the appendicular skeleton comes from the French sites of Pontlevoy (MN5), Aérotrain (MN4), and Artenay (MN4). The postcranial skeleton of Amphimoschus is relevant to determine its phylogenetic affinities within the Pecora and to better understand the evolution of cervoids, the pecoran ruminants more closely related to deer. Our total-evidence tip-dating phylogenetic analysis recovers three well-supported main lineages of crown pecorans (Giraffomorpha, Bovidomorpha and Cervidomorpha) and places Amphimoschus as a basal member of a monophyletic Cervoidea. Thus, we reject the recent assignment of Amphimoschus to the Bovoidea, and confirm the presence of hornless forms at the base of the cervoid clade. We define the Cervoidea as the least inclusive clade of crown pecorans including Amphimoschus and the Cervidae. We also define the Cervidomorpha as the least inclusive clade of crown pecorans containing Namibiomeryx and the Cervidae. Cervidomorphs were relatively successful in the Miocene, spreading through Africa, Eurasia and North America during the Early–Middle Miocene. Amphimoschus xishuiensis Y.-K. Li et al., 2021 is recovered here as the closest sister group to the Bovidae and hence cannot be considered to belong to the genus Amphimoschus. We erect for it the new genus Dimidiomeryx. Our topology adds complexity to the recently revamped hypothesis based on molecular data regarding the single origin of the cranial appendages in pecoran ruminants. Amphimoschus probably had a sitatunga-like lifestyle, sporting sprawling-out fingers with very long third phalanges, long limbs and a general configuration of the appendicular skeleton that probably allowed it to live in swampy/semiaquatic environments.

Masticatory myology of the llama (Lama glama, Camelidae) andcomparisons with other camelids and euungulates.

Camelids are the only living representatives of the Suborder Tylopoda, and present a unique set of osteo-myological masticatory features, differing from all other extant euungulates. They combine selenodont dentition and rumination with a fused symphysis, and roughly plesiomorphic muscle proportions. Despite its potential relevance as an euungulate model in comparative anatomy studies, the available data is strikingly scarce. The present study represents the first description of the masticatory muscles of a Lamini, analyzing the functional morphology of Lama glama and other camelids in a comparative framework. Both sides of the head of three adult specimens from Argentinean Puna were dissected. Descriptions, illustrations, muscular maps, and weighing of all masticatory muscles were performed. Some facial muscles are also described. The myology of llamas confirms that camelids possess relatively large temporalis muscles, with Lama being less extreme than Camelus. This plesiomorphic feature is also recorded in suines and some basal euungulates. Conversely, the direction of the fibers of the M. temporalis is mainly horizontal, resembling grinding euungulates such as equids, pecorans, and some derived suines. Although the M. masseter of camelids and equids do not reach the particularly modified configuration of pecorans, in which it is rostrally extended and arranged horizontally, the posterior sectors of Mm. masseter superficialis and pterygoideus medialis have acquired relatively horizontal disposition in the former lineages, suitable for protraction. The pterygoidei complex presents several bundles, and its relative size is intermediate between suines and derived grinding euungulates. The whole masticatory muscles are relatively light when compared to jaw weight. The evolution of the masticatory muscles and chewing of camelids implied that grinding abilities were reached with less extreme modifications of the topography and/or proportions than pecoran ruminants and equids. A relatively large M. temporalis recruited as a powerful retractor during the power stroke is a key feature of camelids. The relaxed pressure on chewing derived from the acquisition of rumination explains the slenderer build masticatory musculature of camelids compared to other euungulates except ruminants.

Miocene Moschidae (Mammalia, Ruminantia) from the Linxia Basin (China) connect Europe and Asia and show an early evolutionary diversity of a today monogeneric family

Moschidae are the only pecoran ruminants where all representatives totally lack cranial appendages today. Latest phylogenetic studies name them the sister group of Bovidae. Thus, cladogenesis of Moschidae and Bovidae should be older than the earliest known bovids (∼18 Ma). However, the oldest known moschid fossil so far dates to about 16 Ma years old in Eastern Europe. This and other early records so far comprise few fossils and thus, the early evolution as well as the origin of the extant Moschus is not yet fully known. Here, we report new results on the Moschidae from the Shinanu Fauna, Linxia Basin, older than 15 Ma. New and historic material reveal some of the oldest records of Moschidae and an unexpected rich diversity, especially for this early phase of evolution. A new taxon, ‘Micromeryx’ caoi sp. nov., presents affinities with the late Middle Miocene species ‘M.’ eiselei from Steinheim am Albuch. The second new taxon represents the oldest described Hispanomeryx species, Hispanomeryx linxiaensis sp. nov. and confirms an Asian Hispanomeryx-lineage. Furthermore, there may be one additional so far undetermined large moschid in the basin during this time slice. Our results provide essential data for a possible Asiatic origin of the Moschidae, and for their early evolution, and improve our understanding of terrestrial Early Miocene ecosystems in East Asia.

Ruminant mesowear reveals consistently browse-dominated diets throughout the early and middle Miocene of eastern Africa

The ecological preferences of ruminant artiodactyls are commonly used to reconstruct the paleoenvironment of Neogene fossil localities throughout Africa. However, comparatively little research has focused on the ecology of ruminant artiodactyls from the Miocene of Africa. Here, we contribute new molar mesowear and hypsodonty data for the ruminant artiodactyls from the early and middle Miocene of Kenya and Uganda. Macroscopic dental characteristics of 608 tragulids, stem pecorans, giraffoids, and bovids dated to between 20 and 13.7 Ma were analyzed. Our hypsodonty results reveal that, whereas tragulids remain brachydont throughout the early and middle Miocene, pecoran ruminants experience an increase in hypsodonty due to the appearance of high-crowned bovids and climacoceratids that migrate into eastern Africa in the middle Miocene. Results from dental mesowear analysis suggest that all tragulids and pecorans were likely browsers, with only one taxon showing mesowear values that overlap with both browsers and mixed feeders in both the upper and lower molars (Canthumeryx sirtensis). None of the taxa analyzed had mesowear scores indicative of a grazing diet. Surprisingly, middle Miocene bovids and climacoceratids, despite possessing gross tooth morphologies adapted to abrasive diets, were largely utilizing a browsing diet. Although the early and middle Miocene habitats of eastern Africa were likely very heterogenous, none of the ruminant artiodactyls present in these habitats is interpreted as having incorporated grasses into their diet in significant quantities.

Micromeryx? eiselei-A new moschid species from Steinheim am Albuch, Germany, and the first comprehensive description of moschid cranial material from the Miocene of Central Europe.

Moschids are enigmatic pecoran ruminants whose phylogeny is still not fully understood. So far we know only little of the family’s early evolutionary history and the origin of the modern genus, Moschus. Here we present a comprehensive description of cranial material, including the ear region and the dentition, of fossil moschid material from the Middle Miocene locality Steinheim am Albuch (13.5 Ma; Germany). This study provides the first exhaustive dataset for the cranial osteology of Micromeryx flourensianus, the most likely oldest true moschid. It furthermore reveals the presence of a second, so far undescribed moschid species, we here name Micromeryx? eiselei, in the abundant material from the locality. The two taxa can be clearly distinguished by characters of the skull, the ear region, the dentition, as well as by size. This evidences the sympatric occurrence of two moschid species in the locality Steinheim am Albuch.

The evolution of interferon-tau.

Thirty years ago, a novel type I interferon (IFN) was identified by molecular cloning of cDNA libraries constructed from RNA extracted from ovine and bovine pre-implantation embryos. This protein was eventually designated as IFN-tau (IFNT) to highlight its trophoblast-dependent expression. IFNT function is not immune related. Instead, it interacts with the maternal system to initiate the establishment and maintenance of pregnancy. This activity is indispensable for the continuation of pregnancy. Our review will describe how IFNT evolved from other type I IFNs to function in this new capacity. IFNT genes have only been identified in pecoran ruminants within the Artiodactyla order (e.g. cattle, sheep, goats, deer, antelope, giraffe). The ancestral IFNT gene emerged approximately 36 million years ago most likely from rearrangement and/or insertion events that combined an ancestral IFN-omega (IFNW) gene with a trophoblast-specifying promoter/enhancer. Since then, IFNT genes have duplicated, likely through conversion events, and mutations have allowed them to adapt to their new function in concert with the emergence of different species. Multiple IFNT polymorphisms have been identified in cattle, sheep and goats. These genes and gene alleles encode proteins that do not display identical antiviral, antiproliferative and antiluteolytic activities. The need for multiple IFNT genes, numerous alleles and distinct activities remains debatable, but the consensus is that this complexity in IFNT expression and biological activity must be needed to provide the best opportunity for pregnancy to be recognized by the maternal system so that gestation may continue.

A new assemblage of stem pecoran ruminants from the Oligocene Chitarwata Formation, Bugti Hills, Baluchistan, Pakistan: Paleoenvironmental and paleobiogeographic implications

A new assemblage of stem pecoran ruminants from the Oligocene Chitarwata Formation (lower Bugti Member), Bugti Hills (Pakistan), consists of three identified genera and another indeterminate ruminant. Although limited, the dental and postcranial material is sufficient to identify the genera Amphitragulus and Mosaicomeryx, two common forms known from middle to late Oligocene deposits of Europe, thus reinforcing the ‘middle’ Oligocene age of the lowermost Chitarwata Formation. Mosaicomeryx is reported for the first time from the Indian Subcontinent and this occurrence considerably expands its geographical distribution. A new genus and species, Paalitherium gurki, is erected on the basis of an unusual and unique association of characters on its lower molars. The unclear definition and occurrences of? Gelocus gajensis Pilgrim, 1912 are re-examined in the light of new data from the Bugti and Zinda Pir areas (Pakistan). The new ruminant fauna from Paali is clearly distinctive from the early Miocene assemblage known from Bugti. In accordance with other fossil evidence, the ruminant fauna described here suggests the existence of a tropical forested environment under monsoonal regime with soft food supplies during the time of deposition of the lowermost Chitarwata Formation.

A Dorcatherium (Mammalia, Ruminantia, Middle Miocene) petrosal bone and the tragulid ear region

ABSTRACTA petrosal bone from the French Middle Miocene locality Sansan is described. It belongs to the tragulid species Dorcatherium crassum. Using high-resolution X-ray computed tomography, we scanned this petrosal bone and segmented its embedded bony labyrinth. We compared the morphological data with those of three living Tragulidae: Tragulus javanicus, Hyemoschus aquaticus, and Moschiola meminna. We ran a phylogenetic analysis where fossil and extant pecoran ruminants were included to understand the distribution of characters of the petrosal bone and bony labyrinth within ruminants. We propose a set of new synapomorphies for the Tragulidae among the Ruminantia, including the absence of the basicapsular groove, a knob-shaped mastoid region, a knob anterior to the subarcuate fossa on the petrosal bone, a high number of cochlea turns, the dorsal insertion of the posterior limb of the lateral semicircular canal, the extension of the lateral semicircular canal beyond the plane of the posterior semicircular canal in dorsal view, and a pouch-like endolymphatic sac on the bony labyrinth. The clade constituted by Tragulus and Moschiola is confirmed by new synapomorphies such as a double convexity of the promontorium and a large pouch-like endolymphatic sac that covers the common crus. We demonstrate the potential of characters of the bony labyrinth for the phylogeny of ruminants.SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVPCitation for this article: Mennecart, B., and L. Costeur. 2016. A Dorcatherium (Mammalia, Ruminantia, Middle Miocene) petrosal bone and the tragulid ear region. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1211665.

Cranial arterial pattern of the Sri Lankan spotted chevrotain,Moschiola memmina, and comparative basicranial osteology of the Tragulidae

The cranial arterial pattern of artiodactyls deviates significantly from the typical mammalian pattern. One of the most striking atypical features is the rete mirabile epidurale: a subdural arterial meshwork that functionally and anatomically replaces the arteria carotis interna. This meshwork facilitates an exceptional ability to cool the brain, and was thought to be present in all artiodactyls. Recent research, however, has found that species of mouse deer (Artiodactyla: Tragulidae) endemic to the Malay Archipelago possess a complete a. carotis interna instead of a rete mirabile epidurale. As tragulids are the sister group to pecoran ruminants, the lack of a rete mirabile epidurale in these species raises intriguing evolutionary questions about the origin and nature of artiodactyl thermoregulatory cranial vasculature. In this study, cranial arterial patterns are documented for the remaining species within the Tragulidae. Radiopaque latex vascular injection, computed tomography (CT-scanning), and digital 3-dimensional anatomical reconstruction are used to image the cranial arteries of a Sri Lankan spotted chevrotain, Moschiola meminna. Sites of hard and soft tissue interaction were identified, and these osteological correlates were then sought in nine skulls representative of the remaining tragulid species. Both hard and soft tissue surveys confirm that the presence of an a. carotis interna is the common condition for tragulids. Moreover, the use of a 3-D, radiographic anatomical imaging technique enabled identification of a carotico-maxillary anastomosis that may have implications for the evolution of the artiodactyl rete mirabile epidurale.

Old World Ruminant Morphophysiology, Life History, and Fossil Record: Exploring Key Innovations of a Diversification Sequence

The omasum of pecoran ruminants (which is absent in tragulids) and shorter gestation periods in non-giraffid crown pecorans (as opposed to giraffids) could represent cases of key innovations that caused disparity in species diversity in extant ruminants. Literature suggests that the different ruminant groups inhabited similar niche spectra at different times, supporting the ‘increased fitness’ interpretation where a key innovation does not mainly open new niches, but allows more efficient use of existing ones. In this respect, we explored data on fossil species diversity of Afro-Eurasian ruminants from the Neogene and Quaternary. Tragulid and giraffid diversity first increased during the Early/Middle Miocene with subsequent declines, whereas bovid and cervid diversity increased distinctively. Our resulting narrative, combining digestive physiology, life history and the fossil record, thus provides an explanation for the sequence of diversity patterns in Old-World ruminants.

Dorcatherium naui and pecoran ruminants from the late Middle Miocene Gratkorn locality (Austria)

One of the rare records of a rich ruminant fauna of late Middle Miocene age (Sarmatian sensu stricto; 12.2–12.0 Ma) was discovered at the Gratkorn locality (Styria, Austria). It comprises, besides Micromeryx flourensianus, ?Hispanomeryx sp., Euprox furcatus, Palaeomerycidae gen. et sp. indet., and Tethytragus sp., one of the oldest records of Dorcatherium naui. Gratkorn specimens of the latter species are in metric and morphologic accordance (e.g. selenodont teeth, bicuspid p2, non-fusion of malleolus lateralis and tibia) with type material from Eppelsheim (Germany) and conspecific material from Atzelsdorf (Austria), and do not show an intermediate morphology between Late Miocene Dorcatherium naui and Middle Miocene Dorcatherium crassum, thus enforcing the clear separation of the two species. It furthermore confirms the assignation of Dorcatherium naui to a selenodont lineage (together with Dorcatherium guntianum) distinct from a bunoselenodont lineage (including Dorcatherium crassum). The record of ?Hispanomeryx sp. is the first of this genus in Central Europe. While Tethytragus sp. could also be a new bovid representative for the Sarmatian of Central Europe, Micromeryx flourensianus and Euprox furcatus are well-known taxa in the Middle Miocene of Central Europe, but comprise their first records from Styria. Morphological data from this work in combination with isotopic measurements (δ18OCO3, δ13C; Aiglstorfer et al. 2014a, this issue) indicate a niche partitioning for the ruminants from Gratkorn with subcanopy browsing (Euprox furcatus), top canopy browsing (Tethytragus sp.) and even a certain amount of frugivory (Dorcatherium naui and Micromeryx flourensianus).

Dietary behaviour and competition for vegetal resources in two Early Miocene pecoran ruminants from Central Spain

Dietary behaviour and competition for resources are investigated for the small-sized ruminants Andegameryx Ginsburg, 1971 and Procervulus Gaudry, 1877 representatives of two largely distinct states of diversification of pecorans. Results obtained from dental microwear and mesowear methodologies are concordant with a mixed feeder strategy for the taxa from the Early Miocene environments of the Iberian Chain (Central Spain). Further, the Spanish taxa investigated had less abrasive diets than their relatives from others similarly aged localities in Europe. This fact raises an important evolutionary uncertainty concerning the traditional characterization of first pecorans as specialized browsers. Instead, data strongly corroborate the recently proposed notion that some Pecora ruminant lineages were able to consume a mixture of browse and grass, and that were originally facultative mixed feeders. However, there is a large degree of variation of their dental wear features. Species were not dependent on a limited type of vegetation and, consequently, were able to exploit different food resources. Dental wear data seem to indicate that these ruminants did not compete for vegetation. In addition, last Andegameryx and earliest Procervulus apparently had a sufficiently different body size to partition the available vegetation in terms of height above ground level to elude competition. Body size difference coupled with an important degree of dietary opportunism may have been factors necessary for their coexistence.

Boreameryx, an unusual new artiodactyl (Mammalia) from the Pliocene of Arctic Canada and endemism in Arctic fossil mammals

Boreameryx braskerudi, gen. et sp. nov., from Early Pliocene (about 5–4 Ma) deposits of Ellesmere Island, Nunavut, is represented by the posterior portion of a dentary with three molars, a partial calcaneum, unciform, and fragments of long bones and ribs. The incompletely known structure of Boreameryx must leave open the questions of its relationships within the pecoran ruminants. Even its possible affinities with early cervoids and the North American blastomerycines are speculative. We favour the tentative association of Boreameryx within the Cervoidea. Rather than evolving hypsodonty to deal with abrasive northern foods, Boreameryx apparently retained plesiomorphic dental structures—even augmenting those structures in a unique morphological development. We hypothesize, based on recorded relationships and ranges (both geological and geographical) of several Beaver Pond site mammals, including Boreameryx, that they indicate a significant interval of endemic development in a high northern biotic province prior to 5 Ma.

Los Rumiantes (Artiodactyla, Mammalia) del Mioceno inferior de La Encinilla (Colmenar Viejo, Madrid)

This article is a preliminary study of the fossil ruminants found in the Early Miocene site of La Encinilla (Colmenar Viejo, Madrid). The morphological description of dentition and postcranial bones, along with the metrical and comparative study with material from localities of similar age in France and Spain has allowed us to confirm the presence of two Pecoran ruminants in La Encinilla: Andegameryx sp. and a larger species related to Teruelia Moya-Sola, 1987. Although the identification in one of the cases should be confirmed with more material, the record in the Madrid Bassin would represent new information regarding the known biogeographical distribution of both taxa. The systematic position of Andegameryx and Teruelia is still under discussion, but both forms are clearly distinct from the Cervoidea ruminants found in Europe and the Iberian Peninsula at the same age, such as Amphitragulus, Oriomeryx, Bedenomeryx or Dremotherium.

Distribución biocronológica de los Moschidae (Mammalia, Ruminantia) en España

The Moschidae are a group of hornless pecoran ruminants that showed a high specific diversity during the Middle and Upper Miocene in Spain. Moschids registered by the first time at the local zone Db with two species, Micromeryx flourensianus and Micromeryx sp. nov. 1. The latter species becomes extinct at local zone E, and it is substituted by Micromeryx sp. nov. 2, which shows a more derived dentition. From local zone G to local zone J and during a four million year period, the specific diversity of the Spanish Moschidae becomes higher, coinciding with the first record and diversification of the genus Hispanomeryx since local zone F times. During all this period (zones G to J) a minimum number of three moschid species always exists, with a maximum peak of four species during the zones G3 and H; this time span of 2,5 million years can be considered the moschid diversity apogee in the Iberian Peninsula, and it is dominated by the species Micromeryx sp. nov. 3. At local zone H a new moschid association dominated by Micromeryx sp. nov. 4 appears. The Moschidae became totally extinct in Spain 8 million years ago at local zone K.

Identification of interferon-$tau; isoforms expressed by the peri-implantation goat (Capra hircus) conceptus

Interferon-tau (IFN-τ) is the maternal recognition of pregnancy factor in pecoran ruminants. The aims of this study were to identify the various IFN-τ transcripts in the peri-implantation caprine (ca) conceptus and to compare these nucleotide sequences phylogenetically with established mRNA sequences from the goat. Conceptuses (n=5) were collected from Boer crossbred and Angora female goats by laparotomy at days 17 and 18 of pregnancy. Total cellular RNA was extracted and RT-PCR was performed by standard procedures using a DNA polymerase with proofreading activity and gene-specific primers complimentary to non-coding regions of the published caIFN-τ sequence. Nine distinct nucleotide sequences were isolated that encode five distinct caIFN-τ proteins. These caIFN-τ have greater sequence homology with ovine IFN-τ (94–96% nucleotide identity; 90–93% amino acid identity) than with bovine IFN-τ (<92% nucleotide identity; <85% amino acid identity). The novel caIFN-τ isoforms contained pronounced nucleotide and amino acid sequence identity with one another (97–99% nucleotide identity; 94–99% amino acid identity) but only moderate sequence identity with the previously identified caIFN-τ (94–96% nucleotide identity; 87–90% amino acid identity). In conclusion, multiple caIFN-τ mRNA species are expressed during peri-implantation conceptus development and distinct clusters of caIFN-τ genes appear to have evolved in this species.

Effects of oxidative stress and inhibitors of the pentose phosphate pathway on sexually dimorphic production of IFN‐τ by bovine blastocysts

Bovine interferon-tau (IFN-tau), the anti-luteolytic factor secreted by conceptuses of pecoran ruminants, is a product of autosomal genes, yet in vitro produced (IVP) female expanded blastocysts (EB) secrete about twice as much IFN-tau as males. Two possible explanations have been tested here. One is that embryos of one sex are differentially susceptible to oxidative stress. The second is that female EB produce more IFN-tau because pentose-phosphate pathway (PPP) activity is elevated as a result of delayed X-chromosome inactivation. IVP bovine zygotes were cultured to the 8-cell stage and placed under conditions designed either to promote oxidative stress (+/-H2O2; 20 vs. 5% O2), or to inhibit glucose 6-phosphate dehydrogenase (G6PDH) activity (addition of dehydroepiandrosterone, DHEA or 6-aminonicotinamide, 6-AN to the medium). At day 8, blastocysts were cultured individually for a further 48 hr to assess IFN-tau production, and embryo sex determined retrospectively. Blastocyst numbers were reduced (P < 0.05) and their continued development impaired (P < 0.05) in presence of H2O2 (200 microM) and 20% O2, but neither IFN-tau production nor sexually dimorphic expression of IFN-tau were affected. IFN-tau production was reduced, particularly in females (P < 0.05), and sexual dimorphic differences in production were lost in the presence of both DHEA (100 microM) and 6-AN (1 microM). In the case of 6-AN, these effects were achieved without a significant decline in blastocyst developmental progression, quality, or cell number. The data suggest that the higher production of IFN-tau by female EB is an indirect outcome of the increased activity of the oxidative arm of the PPP pathway.

Identification of interferon-τ isoforms expressed by the peri-implantation goat ( Capra hircus) conceptus

Interferon-tau (IFN-τ) is the maternal recognition of pregnancy factor in pecoran ruminants. The aims of this study were to identify the various IFN-τ transcripts in the peri-implantation caprine (ca) conceptus and to compare these nucleotide sequences phylogenetically with established mRNA sequences from the goat. Conceptuses ( n=5) were collected from Boer crossbred and Angora female goats by laparotomy at days 17 and 18 of pregnancy. Total cellular RNA was extracted and RT-PCR was performed by standard procedures using a DNA polymerase with proofreading activity and gene-specific primers complimentary to non-coding regions of the published caIFN-τ sequence. Nine distinct nucleotide sequences were isolated that encode five distinct caIFN-τ proteins. These caIFN-τ have greater sequence homology with ovine IFN-τ (94–96% nucleotide identity; 90–93% amino acid identity) than with bovine IFN-τ (<92% nucleotide identity; <85% amino acid identity). The novel caIFN-τ isoforms contained pronounced nucleotide and amino acid sequence identity with one another (97–99% nucleotide identity; 94–99% amino acid identity) but only moderate sequence identity with the previously identified caIFN-τ (94–96% nucleotide identity; 87–90% amino acid identity). In conclusion, multiple caIFN-τ mRNA species are expressed during peri-implantation conceptus development and distinct clusters of caIFN-τ genes appear to have evolved in this species.

Digestion and passage rates of grass hays by llamas, alpacas, goats, rabbits, and horses

Many studies have suggested that South American camelids (SAC) have greater digestive efficiency than pecoran ruminants, but others have found no difference. In an effort to provide new data on this issue, we investigated the ability of SAC (alpacas and llamas), goats, horses, and rabbits to digest C 3 ( Bromus inermis) and C 4 ( Cynodon dactylon) grass hay with nearly equal nitrogen and cell wall concentrations. Dry matter digestibility (DMD) of the C 3 grass hay was not significantly different between SAC and goats. Foregut fermenters (SAC and goats) digested C 3 and C 4 grasses more efficiently than hindgut fermenters (horses and rabbits). SAC digested C 4 grass hays more efficiently than goats, possibly due to their relatively longer particulate matter mean retention times (71 and 54 h, respectively). Apparent nitrogen digestibility was 9% higher for all species with the C 3 grass in comparison to C 4 grass. This suggests that the highly-vascularized bundle sheath cells of C 4 plants prevent efficient utilization of dietary nitrogen.

SINE retrotransposition during the evolution of the Pecoran ruminants.

SINE retrotransposition events have proven their value as phylogenetic markers in several eukaryotic taxa at different taxonomic levels. The genomes of ruminants contain three related SINE elements, Bov-tA, Bov-A2, and Bov-B. To estimate the time points of retrotransposition of individual copies of these SINEs, we designed PCR primers on database sequences containing SINE insertions in cattle, sheep, or goat genomes and tested for the presence of these copies in the genomes of other ruminants. It was checked by sequencing whether length variation of the PCR products reflected a SINE retrotransposition. One Bov-B and nine Bov-tA insertions were shared by cattle, sheep, goat, and giraffe, indicating an early retrotransposition event before the radiation of the Pecora, while three other Bov-tA and two Bov-B elements were apparently inserted later. The ruminant alpha-lactalbumine gene contains a hotspot of early and more recent Bov-tA insertions, a Bov-tA replacement as well as a recent Bov-B insertion. Three Bov-A2 insertions were found to be shared only by the Bovidae, the Bovini, and the Bos and Bison species, respectively, indicating that most Bov-A2 insertions are relatively recent. The time elapsed since the retrotransposition was also reflected in the degeneration of the direct repeats that flank SINE inserts. We suggest that retrotransposition of SINEs may serve as phylogenetic markers in the ruminant families, subfamilies, and even tribes. In addition, sequencing of SINE insertions revealed several other unique deletions/insertions that also may be informative for phylogenetic reconstructions of ruminants.