كليدواژه :
فسيل مهره‌دار , ميوسن , پليوسن , جنوب اردبيل , پستانداران
چكيده فارسي :
ﻻﯾﻪﻫﺎي ﻓﺴﯿﻞدار ﺣﺎوي ﺑﻘﺎﯾﺎي ﻣﻬﺮهداران در ﺗﻮاﻟﯽﻫﺎي رﺳﻮﺑﯽ ﻣﺤﯿﻂ ﺧﺸﮑﯽ در ﺟﻨﻮب اﺳﺘﺎن اردﺑﯿﻞ )ﺷﻬﺮﺳﺘﺎن ﮔﯿﻮي( ﺑﺮاي اوﻟـﯿﻦ ﺑـ ﺎر در اﯾـﻦ ﻣﺤﺪوده ﯾﺎﻓﺖ و ﮔﺰارش ﻣﯽﺷﻮد. ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﻣﺤﻞ ﻻﯾﻪﻫﺎي ﻓﺴﯿﻞدار ﮐﻪ در دﯾﻮاره ﺗﺮاﻧﺸﻪ رﺧﻨﻤﻮن داﺷﺖ، ﻣﺮاﺣﻞ اﺳﺘﺨﺮاج از ﻗﺒﯿـﻞ ﺧـﺎك ﺑـﺮداري، ﺗﺤﮑﯿﻢ و ﺟﺪاﺳﺎزي از ﻻﯾﻪﻫﺎ ﺑﺎ در ﻧﻈﺮ ﮔﺮﻓﺘﻦ ﺣﻔﻆﺷﺪﮔﯽ ﺑﺴﯿﺎر ﺿﻌﯿﻒ، ﺑﺎ دﻗﺖ، اﻧﺠﺎم ﺷﺪ. اﺟﺰا و ﻗﻄﻌﺎت ﻗﺎﺑﻞ ﺷﻨﺎﺳﺎﯾﯽ ﺷﺎﻣﻞ دﻧﺪان، اﺳﺘﺨﻮان زﻧﺪ زﺑﺮﯾﻦ و زﯾﺮﯾﻦ، ﻗﺴﻤﺖ ﺑﺎﻻي اﺳﺘﺨﻮان ﮐﻒ ﭘﺎ و ﻗﻄﻌﺎت دﯾﮕﺮ از زراﻓﻪ و دﻧﺪان آﺳﯿﺎي اول ﺗﺎ ﺳﻮم ﻓﮏ ﺑـﺎﻻ )M1-M3( ﺧـﺎﻧﻮاده ﮔﺎوﺳـﺎﻧﺎن، اﺳـﺘﺨﻮان ﮐﻒ ﭘﺎ، دﻧﺪان ﭘﯿﺶ ﺧﺎﻧﻮاده اﺳﺐ ﺳﺎﻧﺎن و ﻗﻄﻌﺎت ﺧﺎﻧﻮاده ﻓﯿﻞﻫﺎ ﻣﯽﺑﺎﺷﺪ. ﻣﻄﺎﻟﻌﻪ وﯾﮋﮔﯽﻫﺎي ﻣﺎﮐﺮوﺳﮑﭙﯽ ﻧﻤﻮﻧﻪﻫﺎي ﯾﺎﻓﺖ ﺷﺪه ﺑﻪ روﺷـﻨﯽ ﺣـﺎﮐﯽ از ﺟﺎﺑﻪﺟﺎﯾﯽ ﻗﺒﻞ از ﻓﺴﯿﻞ ﺷﺪن ﻧﻤﻮﻧﻪﻫﺎ اﺳﺖ. ﺗﻨﻮع دﯾﺮﯾﻨﻪ زﯾﺴﺘﯽ ﻣﺬﮐﻮر در ﻻﯾﻪ ﻓﺴﯿﻞدار ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﯾﺎدآور ﺗﺸﺎﺑﻪ ﺑﺎﻻي ﻓﻮﻧﺎي زﯾﺴﺘﯽ دﯾﺮﯾﻨـﻪ در ﺑﺨﺶﻫﺎي ﻓﺴﯿﻞدار ﻣﺮاﻏﻪ ﻣﯽﺑﺎﺷﺪ. ﺳﻦ ﻧﺴﺒﯽ ﻓﺴﯿﻞﻫﺎي ﯾﺎﻓﺖ ﺷﺪه ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ وﯾﮋﮔﯽﻫﺎي دﯾﺮﯾﻨﻪ ﺷﻨﺎﺧﺘﯽ و ﺗﻄﺎﺑﻖ ﭼﯿﻨﻪاي ﺗﻮاﻟﯽ رﺳـﻮﺑﯽ ﻣﻮﺟـﻮد ﻣﯿﻮﺳﻦ ﭘﺴﯿﻦ ـ ﭘﻠﯿﻮﺳﻦ ﭘﯿﺸﯿﻦ ﺗﻌﯿﯿﻦ ﻣﯽﺷﻮد.
چكيده لاتين :
Introduction
This study is the first report of the terrestrial mammalian vertebrate fossils from the south of Ardabil. Terrestrial vertebrate fossil beds have great importance in paleontology studies. The role of these types of fossil groups is crucial in understanding paleoenvironments. In this study, extraction and identification of terrestrial vertebrate fossils families such as Bovidae, Equidae, Giraffidae, and Elephantidae are discussed.
Materials and methods
Study area in Northwest of Iran, South of Ardebil and is in Kiwi city. The fossil layer studied in a railway trench at a height of 9 meters from the axial plane. After constructing a drilling platform at the trench and reticulation of platform fossil part extraction operations were done. Then, complete removal of parts from sediments and repair of damaged specimens and measurement of the required parameters was done. Systematic studies were also done based on information from fossil samples. The displacement of pieces of fossil specimens was completely evident before being fossilized by paleo fractures and also by separation from the main part. It should be noted that unfortunately before the fossil layer was found, some fossil parts were destroyed by road construction machinery. Components and identifiable parts included: premolar, Radial bone, Ulna, the top of the metatarsals of Family Giraffidae, Maxillary first molar to third (M1-M3) of Family Bovidae, metatarsals and incisors tooth of Family Equidae, Part of the femoral head Family Elephantidae.
Discussion
Fossil parts of this study have the ability to reflect the characteristics of their paleoenvironment. Discussing these features from dental samples is more comprehensible and defensible. The exact study of dental Feature of different species of mammalian fossils with a vegetarian diet in Maragheh fauna and the study area was limited to the domain of fodder diets (family of Bovidae and Equidae) and leaf diets (family of Giraffidae), There is also the presence of various species of fossils such as Giraffidae, Bovidae, Equidae and even Elephantidae that exhibit these diets, which confirmed this type of nutrition at the time of its existence (Late Miocene). Therefore, using the study of the hypsodont tooth in the family of Bovidae and species of Equidae, as well as the presence of brachyodont type teeth in Giraffidae species, It can be said that the paleoenvironment of the studied area and Maragheh should be rich in grassland cover (hypsodont type), and in terms of tree cover to the extent that the leaf (brachyodont type) is used to feed it. Therefore, it is possible to compare the paleoenvironment of the studied area and Maraghe with some of the Savannah environments of today's Africa. As a result, the paleoenvironment Northwest of Iran (with a stronger probability of the southern provinces of Ardebil and Tabriz) in the Late Miocene could have been in the form of a vegetation plain with grasses, among which there were low shrubs. The study area is comparable to that of Maragheh fauna in terms of conditions the paleoenvironment and paleogeography and placing in the upper Miocene migration belt (Fortelius et al., 2003).
Conclusion
Different groups in the fossil layer including the family of Bovidae, Equidae, Giraffidae, and Elephantidae were extracted and identified. Initial field and laboratory studies indicate the transport of fossil parts before fossilization. Evidence of these displacements is the pre-fossil fractures, as well as the discovery of teeth from the jawbone. Fossil parts are oriented which specifies the direction of the paleo-currents. The sedimentary sequence of the fossiliferous layer contained sandy and clay layers. Regarding the importance of systematically studying these types of fossil groups, the finding of these fossils contributes greatly to recognizing the paleoenvironment for understanding the type of environment, biodiversity, and so on. This fauna can be compared to the co-eval fauna of the Maragheh representing a similar paleoenvironmental and paleogeographical character. The relative age of fauna can be assigned the late upper Miocene to earliest Pliocene.
