Classification

Common name: Loggerhead Sea Turtle
The common name "loggerhead" comes from their massive head (Widecast, 2013).
Scientific name: Caretta caretta

Domain	Eukayota	Eukaryote: eu-true,karyo-nucleus
Kingdom	Animalia	Animal
Phylum	Chordata	Vertebrate
Class	Reptilia	Reptile
Order	Testudines	Turtles and Tortoises
Family	Cheloniidae	Sea Turtle
Genus	Caretta	Turtle
Species	caretta	Turtle

Domain: Eukarya
    The loggerhead sea turtle belongs to the domain Eukarya. The main characteristic of this domain is that all organisms are eukaryotic, where eu means true and karyo means nut or in this case nucleus (Guill, 1960). Since these cells contain a nucleus, they go through the cell division of mitosis (Sidwill Friends School, 2006). Along with all cells containing a nucleus, they also have membrane bound organelles such as the mitochondria or chloroplasts (Sidwill Friends School, 2006). The domain Eukarya is highly diverse since it contains unicellular, colonial and multicellular organisms (Sidwill Friends School, 2006). In fact three major kingdoms belong to this domain, the kingdoms Plantae, Fungi and Animalia (Campbell et al., 2008).
 
Kingdom: Animalia
    The loggerhead sea turtle belongs to kingdom Animalia (NOAA, 2013). Animalia stems from the Latin animale, derived from animalis which means living andanima meaning soul (Guill, 1960). Kingdoms are distinguished by which way they acquire nutrients. In the kingdom Animalia, organisms obtain their food by digesting other organisms, unlike the kingdom Plantae who produce their own food (Campbell et al., 2008). Loggerhead sea turtles fit into this kingdom since they are omnivorous. For more information on their diet click here.

Phylum: Chordata   
    Loggerhead sea turtles are classified to the phylum Chordata (NOAA, 2013). Chordata stems from the Latin root chorda meaning chord, referring to the characteristic of this phylum, which is having notochord at some point in their development (Guill, 1960; Campbell et al., 2008). Another characteristic of organisms in this phylum is that they are deuterstomes. Deuterstomes stems from the Greek roots deutero meaning second and stoma meaning mouth which refers to the anus forming first and mouth forming second during development (Campbell et al., 2008; Guill, 1960). Deuterstomes are also bilaterally symmetrical (Campbell et al., 2008). Loggerhead sea turtles belong to the subphylum Vertebrata, which stems from the Latin root vertebra meaning a joint or backbone (Duermit, 2007; Guill, 1960). Characteristics of the subphylum vertebrata are that all the organisms have a vertebral column that is a main skeletal structure along the length of its body. Other organisms in the subphylum include fish, other reptiles and mammals (Meyers, 2001). The most closely related phylum to the Chordates is the phylum Echinodermata (Campbell et al., 2008).

Figure 1. The phylogenetic tree of extant species of amniotes. The turtle lineage is orange due to the fact that their placement in a phylogenetic tree is currently unclear. Kelsey Huseth 2013 (Campbell et al., 2008).

 Class: Reptilia
    Loggerhead sea turtle are considered to be reptiles along with snakes, lizards, crocodiles and birds, which places them in the class Reptilia (Duermit, 2007; Myers, 2004). Reptilia is derived from the Latin root word reptilis meaning creeping (Guill, 1960). Reptiles have an amniotic egg which is an egg containing four specialized membranes, one being the amnion, that protects the egg from dessication or other environmental factors (Campbell et al., 2008; Myers, 2004). Another characteristic of reptiles are their epidermal scales made up of a certain protein. Currently, it is not certain as to which position turtles should take in the phylogenetic tree. However recent evidence shows that turtles may be more closely related to crocodiles and birds (Myers, 2004).

Order: Testudines
    The loggerhead sea turtle belongs to the order Testudines (NOAA, 2013). Testudine is the order of reptiles that has 260 living species of turtles and tortoises. Turtles and tortoises, or testudines, are different from other reptiles because they do not have holes in the side of the skull. The loggerhead's are located above or below the eyes and are known as temporal fenestrae. There are three suborders of testudines and they are known as the hidden-necks, the side-necks, and the extinct species (Sea Turtle Conservancy, 2013; Malory, 2013; Jones et al., 2012). Hidden-necks are tortoises or turtles that can hide their head completely in their shells. A side-neck tortoise or turtle has to bend their head horizontally before they can put it into their shell (Jones et al., 2012). One can still see some of their head and neck because they cannot draw in their heads completely. The loggerhead is a hidden-neck testudine, but they have lost their ability to draw in their necks (Jones et al., 2012). Testudines have long lifespans and can live up to over 150 years. Testudines, turtles and tortoises, can be found living on land or underwater. The loggerhead can be found on both, but spends most of its time underwater (Malory, 2013). Testudines use their jaws to feed on prey instead of teeth. Testudines also have three-chambered hearts. Testudines are known to be oviparous which means they lay eggs, but they do not care for their young after they lay their eggs (Malory, 2013).

Family: Cheloniidae
    The loggerhead sea turtle is in the family Cheloniidae (NOAA, 2013).The sea turtles that would fit into this family are very large turtles whose front limbs are stronger than their back limbs (Pecor, 2003). Their limbs are flippers that are made for swimming, not for moving on land.The loggerhead turtle is known to be one of the largest Cheloniids with a carapace that can range up to 213 cm (Pecor, 2003). Their carapace is oval and is covered in bony plates. The plastron of a Cheloniid is smaller than most turtles and attaches to the upper shell by ligaments instead of a bony bridge that many land turtles have. Another characteristic of a Cheloniid is they cannot pull back their limbs or heads into their shells (Seaturtles: Cheloniidae-physical characteristics, 2013; Pecor, 2003). The fossil record for Cheloniids places them among the oldest turtles (Pecor, 2003).

Figure 2. Phylogenetic tree of family Cheloniidae including Caretta caretta. Kelsey Huseth 2013 (Encyclopedia of Life, 2013).

Genus: Caretta
    The genus is monotypic which means it only contains one species. Caretta is a Latin version of the French word “caret” which means turtle, tortoise, or sea turtle (Widecast, 2013; Ananjeva et al., 2006).

Species: caretta
    The species name caretta means the same thing as the genus explained above (caretta comes from the word "caret", meaning turtle, tortoise, or sea turtle) (Widecast, 2013). Loggerheads are known for their large heads and thick, horny beak (Save The Turtles, 2013). Their beak, along with their jaw, allows for the loggerhead to feed on their prey. To learn more about their pray click here. The loggerhead also is the largest hard-shelled turtle with no less than five pairs of lateral scales on their shell (Save The Turtles, 2013; Ananjeva et al., 2006). Their head contains large scales (Ananjeva et al., 2006). Another fact about the loggerhead species is their forelimbs have two claws (Save the Turtles, 2013).The loggerhead species can be found in the Indian, Atlantic, and Pacific Oceans. Their nesting places are in subtropical along with temperate locations (Ananjeva et al., 2006).

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