Abstract | Kornjače (Chelonia, Testudines) spadaju u najstarije danas živuće gmazove na Zemlji koji su se razvili prije oko 200 milijuna godina. Danas je poznato 14 porodica, 90 rodova i oko 300 vrsta kornjača. Podijeljene su na temelju mogućnosti uvlačenja glave i vrata pod oklop na dva podreda – krijovratke i vijovratke. Krijovratke su brojnija i evolucijski uspješnija skupina od vijovratki, te krijovratke broje 11 porodica, a vijovratke samo dvije porodice.
Kornjače žive duže od svih ostalih gmazova i smatraju se dugovječnim životinjama. Tako je poznato da galapagoška kornjača (Geochelone nigra) može doživjeti 150 godina, a mnoge vrste žive oko 50 godina u zatočeništvu.
Oklop je evolucijska novina i njihovo glavno obilježje koje osim zaštitne, ima i ulogu u odvijanju hematopoeze, služi kao spremište masti i vode te kao pufer pH.
Oklop današnjih kornjača prosječno je velik 30 cm, ali postoje i puno veći, kao i manji primjerci među različitim vrstama. Najveća kornjača je sedmopruga usminjača (Dermochelys coriacea) koja može težiti preko 600 kg i 120 cm duljine karapaksa, a među najmanje pripada pauk kornjača (Pyxis arachnoides) s Madagaskara koja je dugačka oko 10 cm.
Na temelju oklopa i razlika u njegovoj građi, boji, veličini te histologiji dugih kostiju danas možemo razlikovati brojne vrste kornjača i saznati podatke o njihovo starosti i porijeklu te načinu života.
S obzirom na način života kornjače su se prilagodile svojim oklopom i lokomotornim aparatom, pa tako kopnene kornjače imaju dva para udova koje završavaju s pet kandži na prsnom udu i s četiri kandže na zdjeličnom udu. Imaju kupolasti karapaks i ravni plastron, dok su se slatkovodne vrste prilagodile na život u vodi tako što su između prstiju razvile plivaće kožice, a morske kornjače imaju ravniji i izduženiji oklop, te su razvile dva para peraja za plivanje i bolju adaptaciju na svoje prirodno stanište.
Koža kornjača uglavnom je suha i debela, bez puno žlijezda i prekrivena većim ili manjim ljuskama u kopnenih kornjača, dok je kod vodenih ona bez ljusaka, s finijom kožom i sluznim žlijezdama koje su kornjačama od važnosti tijekom hibernacije kada spavaju zimski san zakopane u mulju na dnu jezera ili rijeke. Kopnene vrste su uglavnom biljojedi, dok su slatkovodne i morske kornjače svejedi i mesojedi, te su tako kandže kopnenih kornjača tupe, dok su kod slatkovodnih duže i oštrije jer služe za pridržavanje plijena prsnim udovima tokom hranjenja.
Prilikom opisivanja kornjača važno je uzeti pravilne standardne mjere kako bi se njima mogli koristiti za usporedbe znanstvenici u svojim radovima širom svijeta. Kornjače mjerimo pomičnim mjerilom, ravnalom i savitljivom trakom koja je jedino sredstvo mjerenja opsega. |
Abstract (english) | Turtles (Chelonia, Testudines) are among the oldest now living reptiles on Earth that have evolved about 200 million years. Today we know 14 families, 90 genera and 300 species of turtles. They are divided on the basis of the possibilities for feeding the head and neck under armor on 2 suborder: hidden-neck turtle and sideneck turtles. Hidden-neck turtles are the more numerous and evolutionary successful group having 11 families, whereas sideneck turtles have only 2 families.
Turtles live longer than any other reptiles and are considered to be long-lived animal. It is known that Galápagos tortoise (Geochelone nigra) can experience 150 years, and many species live about 50 years in captivity.
Armour is an evolutionary novelty and their main characteristic that besides protection, has a role in facilitating hematopoiesis, serves as a storage of fat and water, and as a pH buffer.
The average size of turtle armour in present day is 30 cm, but there are much larger and smaller specimens among different species. The biggest turtle Leatherback turtle (Dermochelys coriacea), which can weigh over 600 kg and 120 cm length of the carapace, and among the least belongs spider tortoise (Pyxis arachnoides) from Madagascar, which is about 10 cm long.
Types of turtles can be distinguished by the following features: type of material of armour, his size, shape and colour. This information can also be used to find out information about their age, origin & lifestyle.
Due to lifestyle turtles have adapted their armor and locomotor apparatus, including land turtles have two pairs of legs that end with five claws on the front feet and 4 claws on their hind legs, with a domed carapace and plastron level, while freshwater species are adapted to life in water such as between the toes have developed webbed feet, and sea turtles are with flatter and elongated shell, and with developed 2 pairs of flippers and better adaptation to their natural habitat. Skin of turtle turtle is mainly dry and thick, without a lot of glands and covered with larger or smaller scales in terrestrial turtles, while the water species are without scales, with a finer skin and mucous glands that are of importance for turtles during hibernation when hibernate buried in the mud on the bottom of the lake or river.
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Terrestrial species are mainly herbivores, while freshwater and sea turtles are omnivores and carnivores, and land turtle claws are blunt, while the freshwater turtle claws are longer and sharper because they serve for holding prey front legs during feeding.
When describing the turtle is important to take proper standard measures in order to promote their use for comparisons of scientists in their work around the world. Turtles can be measured with caliper, ruler and flexible line which is the only means of measuring range. |