Cuscuta, commonly known as dodder or amarbel, is a genus of over 201 species of yellow, orange, or red parasitic plants. Formerly treated as the only genus in the family Cuscutaceae, it now is accepted as belonging in the morning glory family, Convolvulaceae, on the basis of the work of the Angiosperm Phylogeny Group. The genus is found throughout the temperate and tropical regions of the world, with the greatest species diversity in subtropical and tropical regions; the genus becomes rare in cool temperate climates, with only four species native to northern Europe.
The femur, or thigh bone is the only bone in the thigh. The thigh is the region of the lower limb between the hip and the knee. In many four-legged animals the femur is the upper bone of the hindleg.
Copepods are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Some species are planktonic, some are benthic, a number of species have parasitic phases, and some continental species may live in limnoterrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests, bogs, springs, ephemeral ponds, puddles, damp moss, or water-filled recesses of plants (phytotelmata) such as bromeliads and pitcher plants. Many live underground in marine and freshwater caves, sinkholes, or stream beds. Copepods are sometimes used as biodiversity indicators.
Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on comparison with homologous features in related species. The emergence of vestigiality occurs by normal evolutionary processes, typically by loss of function of a feature that is no longer subject to positive selection pressures when it loses its value in a changing environment. The feature may be selected against more urgently when its function becomes definitively harmful, but if the lack of the feature provides no advantage, and its presence provides no disadvantage, the feature may not be phased out by natural selection and persist across species.
Pygopodidae, commonly known as legless lizards, snake-lizards, or flap-footed lizards, is a family of squamates with reduced or absent limbs, and are a type of gecko. At least 35 species are placed in two subfamilies and eight genera. They have unusually long, slender bodies, giving them a strong resemblance to snakes. Like snakes and most geckos, they have no eyelids, but unlike snakes, they have external ear holes and flat, unforked tongues. They are native to Australia and New Guinea.
A parasitic twin, also known as an asymmetrical twin or unequal conjoined twin, occurs when a twin embryo begins developing in utero, but the pair does not fully separate, and one embryo maintains dominant development at the expense of the other. It results from the same processes that also produces vanishing twins and conjoined twins, and may represent a continuum between the two. In parasitic twins, one ceases development during gestation and is vestigial to a mostly fully formed, otherwise healthy individual twin. The undeveloped twin is termed as parasitic, because it is incompletely formed or wholly dependent on the body functions of the complete fetus. The independent twin is called the autosite.
Fetus in fetu is a rare developmental abnormality in which a mass of tissue resembling a fetus forms inside the body of its twin. An early example of the phenomenon was described in 1808 by George William Young.
Isopoda is an order of crustacean, which includes woodlice and their relatives. Members of this group are called Isopods and include both terrestrial and aquatic species. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, and five pairs of branching appendages on the abdomen that are used in respiration. Females brood their young in a pouch under their thorax.
A scotoma is an area of partial alteration in the field of vision consisting of a partially diminished or entirely degenerated visual acuity that is surrounded by a field of normal – or relatively well-preserved – vision.
Ischiopagi comes from the Greek word ischio- meaning hip (ilium) and -pagus meaning fixed or united. It is the medical term used for conjoined twins who are united at the pelvis. The twins are classically joined with the vertebral axis at 180°. The conjoined twins usually have four arms; two, three or four legs; and typically one external genitalia and anus.
The Pentastomida are an enigmatic group of parasitic arthropods commonly known as tongue worms due to the resemblance of the species of the genus Linguatula to a vertebrate tongue; molecular studies point to them being degenerate crustaceans.
Polycephaly is the condition of having more than one head. The term is derived from the Greek stems poly meaning "many" and kephalē meaning "head". A polycephalic organism may be thought of as one being with a supernumerary body part, or as two or more beings with a shared body.
Greig cephalopolysyndactyly syndrome is a disorder that affects development of the limbs, head, and face. The features of this syndrome are highly variable, ranging from very mild to severe. People with this condition typically have one or more extra fingers or toes (polydactyly) or an abnormally wide thumb or big toe (hallux).
Polymelia is a birth defect in which an affected individual has more than the usual number of limbs. It is a type of dysmelia. In humans and most land-dwelling vertebrates, this means having five or more limbs. The extra limb is most commonly shrunken and/or deformed. The term is from Greek πολυ- "many", μέλεα "limbs".
Supernumerary body parts are most commonly a congenital disorder involving the growth of an additional part of the body and a deviation from the body plan. Body parts may be easily visible or hidden away, such as internal organs.
Lakshmi Tatma is an Indian girl born in 2005 in a village in Araria district, Bihar, with "4 arms and 4 legs." She was actually one of a pair of ischiopagus conjoined twins, one of which was headless because its head had atrophied and chest had not fully developed in the womb, causing the appearance of one child with four arms and four legs. She has undergone surgery to remove these extra limbs.
Worms are many different distantly related bilateral animals that typically have a long cylindrical tube-like body, no limbs, and no eyes.
Twin reversed arterial perfusion sequence, also called TRAP sequence, TRAPS, or acardiac twinning, is a rare complication of monochorionic twin pregnancies. It is a severe variant of twin-to-twin transfusion syndrome (TTTS). In addition to the twins' blood systems being connected instead of independent, one twin, called the acardiac twin, TRAP fetus or acardius, is severely malformed. The heart is missing or deformed, hence the name "acardiac", as are the upper structures of the body. The legs may be partially present or missing, and internal structures of the torso are often poorly formed. The other twin is usually normal in appearance. The normal twin, called the pump twin, drives blood through both fetuses. It is called "reversed arterial perfusion" because in the acardiac twin the blood flows in a reversed direction.
Hemioniscus balani, a species of isopod crustacean, is a widespread parasitic castrator of barnacle in the northern Atlantic Ocean. Its range extends from Norway to the Atlantic coast of France, and as far west as Massachusetts. It is also commonly found on the Pacific coast of North America; it is not known if the Pacific and Atlantic populations are the same species, or if the Pacific population exists following human-assisted introduction.
Phylloxeridae is a small family of plant-parasitic hemipterans closely related to aphids with only 75 described species. This group comprises two subfamilies and 11 genera with one that is fossil. The genus type is Phylloxera. The Phylloxeridae species are usually called phylloxerans or phylloxerids.
