MarketMyotragus
Company Profile

Myotragus

Myotragus is an extinct genus of goat-antelope in the tribe Caprini which lived on the Balearic Islands of Mallorca and Menorca in the western Mediterranean until its extinction around 4,300 years ago. The fossil record of Myotragus on the Balearic Islands extends over 5 million years back to the early Pliocene on Mallorca, thought to have arrived from the European mainland after the evaporation of the Mediterranean Sea during the Messinian Salinity Crisis at the end of the Miocene epoch. Following the refilling of the Mediterranean at the beginning of the Pliocene, the Balearic Islands remained strongly isolated, allowing the evolution of Myotragus to occur over the next 5.3 million years with little outside influence.

History of discovery and taxonomy
The first remains of Myotragus were described by Dorothea Bate in 1909. Bate had been sent a letter by Robert Ashington Bullen, who informed her about a bone-bearing breccia deposit on the east of Mallorca, which prompted her to survey the island for Pleistocene aged cave deposits. Three such deposits were found, which yielded fragmentary remains of Myotragus, including a mostly complete skull, associated with a mandible and atlas vertebra, which was designated the type specimen of the new species and genus Myotragus balearicus. In 1915, Charles William Andrews described more material discovered in the intervening years, including material that had been discovered on Menorca. Species Six sequential chronospecies of Myotragus have been named, representing 5 million years of gradual accumulated morphological change, including a reduction in body size and changes to the locomotor system, the teeth and the visual system. • M. palomboi Bover, Quintana & Alcover, 2010 Early Pliocene, Mallorca • M. pepgonellae Moyà-Solà & Pons-Moyà, 1982 Middle Pliocene, Mallorca • M. antiquus Pons-Moyà, 1977 Late Pliocene (c. 3.6-2.6 Ma), Mallorca • M. kopperi Moya & Pons, 1980 Early Pleistocene, Mallorca • M. batei Crusafont & Angel, 1966 Middle Pleistocene, Mallorca, Menorca • M. balearicus Bate, 1909 Late Pleistocene-Holocene, Mallorca, Menorca The species M. binigausensis Moyà-Solà and Pons-Moyà, 1980 from the Pleistocene of Menorca has been synonymised with M. batei. In 2005, a new genus Insulotragus, was erected by Bolver and Alcover, to house the earliest species that had previously been attributed to Myotragus, but this proposal was not widely accepted. ==Evolution ==
Evolution
The closest fossil relatives of Myotragus are uncertain. A close relationship has been proposed to the genera Aragoral and Norbertia from the Late Miocene of mainland Europe, A 2005 study of a partial mitochondrial genome suggested that Myotragus was the sister group to the genus Ovis, which includes sheep. Later on, the re-opening of the straits and the resultant Zanclean flood, which refilled the Mediterranean at the beginning of the Pliocene around 5.3 million years ago isolated the animal populations on the islands. The Balearic Islands remained strongly isolated following the end of the Messinian Salinity Crisis, with no terrestrial vertebrate species dispersing to Mallorca and Menorca until modern human arrival on the islands during the Holocene, over 5 million years later. On Menorca, a giant rabbit, Nuralagus rex evolved that covered the same niche as Myotragus in Mallorca. With the level of the sea falling due to glacial cycles during the Pleistocene, Mallorca and Menorca were periodically connected and the mammals of Mallorca, including Myotragus colonised Menorca, replacing the giant Menorcan rabbits. Following numerous cycles of connection and separation over the course of the Pleistocene, Menorca and Mallorca separated again at the beginning of the Holocene. ==Description==
Description
The size of Myotragus varied between species, with later species on average smaller than earlier species as well as their mainland relatives, representing an example of insular dwarfism. The early species M. pepgonellae is estimated to have had a body mass of approximately , while the later M. kopperi is estimated to have been approximately . with a 2004 study estimating an adult body mass of around , Over the course of its evolution, the rostrum, the frontmost part of the skull forward of the eyesockets, of Myotragus became progressively shorter, There is little difference in horn core shape between male and female individuals, though it has been suggested that some of the skull bones (the basioccipital, basisphenoid and parietal bone) are thicker in male individuals, and that there are subtle differences in horn core morphology. The species of Myotragus show a progressive reduction in the number of teeth through time, with M. balearicus having an adult dentition comprising a single evergrowing (hypselodont) incisor (a feature highly unusual among Bovidae, the broader group containing caprines, bovines, and antelopes), one premolar, and three molars in each half of the lower jaw, and two premolars and three molars in each half of the upper jaw. By contrast, the earliest species had three incisors, one canine, and two premolars in each half of the lower jaw, as is typical of most ruminants with the incisors not being ever-growing, and a third premolar present in each half of the upper jaw. The teeth in the later species are much more hypsodont (high crowned) than in earlier species. == Paleobiology ==
Paleobiology
Diet While tooth morphology and tooth texture suggests that some earlier Myotragus species may have been grazers or mixed feeders (consuming both grass and browse), This plant is known for toxicity, with a high concentration of poisonous alkaloid compounds, with other boxwood species known to cause toxic effects when ingested by other bovids, suggesting that the digestive system of M. balearicus had developed the ability to effectively process and neutralise the toxins without ill effect. The smoothness of the coprolites suggests that digestion was highly efficient. The hollow skull cavity containing the brain (cranial endocast) of M. balearicus indicates that the areas of the brain and structures associated with vision, sound and smell are small when compared with living caprines, with the brain only being half the size of other comparably sized modern caprines, The smaller brain likely represents an optimisation to the animal's energy budget, as neural tissue is energetically expensive to maintain, and better developed senses were unnecessary in a resource limited environment where there was little need to detect predators. later research suggested that this bone morphology is common to all ruminants and is not unique to Myotragus. Based on counting the lines of arrested growth, it has been estimated that M. balearicus reached maximum size (somatic maturity) and probably sexual maturity at 12 years of age. Analysis of the high-crowned teeth of M. balearicus, shows that they grew more slowly than those of other caprines, with their last teeth erupting at approximately six years of age, likely as an adaptation to their longevity, though the rodent-like evergrowing lower incisor of M. balearicus erupted early, both relative to the posterior teeth and in absolute age compared to other bovids. Based on skeletochronology and dental durability analysis, some individuals of M. balearicus are likely to have reached a lifespan of 27 years, which is exceptionally long relative to its body size. The estimated mortality rates are substantially lower than those found for other members of Bovidae, with a large proportion of individuals surviving into old age. Newborn specimens of M. balearicus are estimated to have been approximately in height with a weight of about , approximately 30% the height and 2% the bodymass of mature adult females, much lower than that of a typical ruminant, in which newborns are usually over half the height and over 4% the mass of their mother, with newborns of M. balearicus having relatively short legs in comparison to those of other bovid newborns (with the long legs typical of newborn bovids thought to be an adaptation for immediate predator avoidance from birth). Compared to living caprines and other artiodactyls, the bones of newborn Myotragus balearicus are more robust. Although the length of pregnancy and number of offspring given birth to at a time is not known for certain, given that M. balearicus clearly had a k-selected life strategy, it has been proposed that M. balearicus only gave birth to a single (or perhaps exceptionally two) offspring at a time, and had a relatively long pregnancy length. It has been speculated that Myotragus balearicus engaged in rutting behaviour like living caprines. William H. Waldren argued that Myotragus balearicus males likely engaged in ramming headbutt contests against rival males and that damage to a number of M. balearicus skulls were as a result of injuries obtained during these contests. However, this proposal was met with skepticism by Damià Ramis and Pere Bover, due to the lack of evidence of impact protection features in the skull of Myotragus, as well as the lack of agility in the limbs of M. balearicus which would have made it unlikely that M. balearicus males could impart enough force to cause damage to the skulls of other males. ==Extinction==
Extinction
Diverse datings indicate that the three native terrestrial mammals of Mallorca and Menorca (Myotragus balearicus, the giant dormouse Hypnomys and the large shrew Nesiotites hidalgo) disappeared all in the same very short period of time, during the third millennium BC. Historically there was debate as to whether the extinctions were caused by climate change, or whether they were exterminated by the first human settlers of the Balearic Islands. The dominant theory is the one that postulates an extinction by human causes. The two other native pre-human terrestrial vertebrates of Mallorca and Menorca, the still living Lilford's wall lizard (Podarcis lilfordi) and Majorcan midwife toad (Alytes muletensis) have been heavily impacted by human presence on the archipelago, and today are only confined to remote areas. In 1967, archaeologists John S. Kopper and William H. Waldren proposed that humans had attempted to domesticate Myotragus following their arrival on the islands. ==See also==
tickerdossier.comtickerdossier.substack.com