Question: Information:  - The pond slider ("Trachemys scripta") is a common, medium-sized semi-aquatic turtle. There are three subspecies of sliders. The most recognizable subspecies is the red-eared slider ("T. s. elegans"), which is popular in the pet trade and has been introduced to other parts of the world by people releasing it to the wild. Baby and juvenile pond sliders have a green shell (carapace) and yellow green skin with dark green striped markings. Markings and colors fade in adults to a muted olive green to brown or orange carapace. Some individuals become almost black with few visible markings. The carapace is oval and flattened for females, round and complex for males. The underside of the shell is yellow with dark markings in the center of each scute, making it easier to determine their sex. However, the markings underside the shell fade as the turtle age.  - A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.  - Organisms of many species are specialized into male and female varieties, each known as a sex, with some falling in between being intersex. Sexual reproduction involves the combining and mixing of genetic traits: specialized cells known as gametes combine to form offspring that inherit traits from each parent. Gametes can be identical in form and function (known as isogamy), but in many cases an asymmetry has evolved such that two sex-specific types of gametes (heterogametes) exist (known as anisogamy).  - The red-eared slider ("Trachemys scripta elegans"), also known as the red-eared terrapin, is a semiaquatic turtle belonging to the family Emydidae. It is a subspecies of the pond slider. It is the most popular pet turtle in the United States and is also popular as a pet in the rest of the world. It has, therefore, become the most commonly traded turtle in the world. It is native to the southern United States and northern Mexico, but has become established in other places because of pet releases, and has become an invasive species in many areas, where it outcompetes native species. The red-eared slider is included in the list of the world's 100 most invasive species published by the IUCN.  - Puerto Rico, (Spanish for "Rich Port") officially the Commonwealth of Puerto Rico ("Free Associated State of Puerto Rico") and briefly called Porto Rico, is an unincorporated territory of the United States located in the northeast Caribbean Sea.  - The Puerto Rican slider ( Trachemys stejnegeri stejnegeri ) is found mainly in Puerto Rico and surrounding areas . It is a relative of the pond slider .  - Bean is a common name for large seeds of several genera of the flowering plant family Fabaceae (also known as Leguminosae) which are used for human or animal food.    Given the information, choose the subject and object entities that have the relation of 'taxon rank'.
Answer:
puerto rican slider , subspecies