Igualmente, si se estudia su proceso de desarrollo embrionario se puede apreciar que durante este aparecen las tres capas germinativas endodermo, mesodermo y ectodermo. Es decir, los sexos se encuentran separados. Hay individuos de sexo femenino e individuos de sexo masculino. Estas suelen ser gruesas en su base y tener forma de pinza. De manera tal que muchos especialistas deciden denominar a esta zona simplemente tronco.
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Laura Klappenbach Updated August 02, Myriapods Myriapoda are a group of arthropods that includes millipedes, centipedes, pauropods, and symphylans. About 15, species of myriapods are alive today. As their name implies, myriapods from the Greek myriads, a myriad, plus photos, foot are noted for having many legs, though the number varies widely from species to species. Some species have fewer than a dozen legs, while others have many hundreds of legs.
The Illacme pipes, a millipede that inhabits central California, is the current record holder for myriapod leg count: This species has legs, the most of all known myriapods. Oldest Evidence The earliest fossil evidence for myriads dates back to the late Silurian Period, about million years ago. Molecular evidence, however, indicates that the group evolved before this, perhaps as early as the Cambrian Period, more than million years ago.
Some Cambrian fossils show similarities to early myriapods, indicating that their evolution could have been underway at that time. The trunk is further divided into multiple segments, each having a pair of appendages, or legs. Myriapods have a pair of antennae on their head and a pair of mandibles and two pairs of maxillae millipedes only have one pair of maxillae. Centipedes have a round, flat head with one pair of antennae, a pair of maxillae, and a pair of large mandibles.
Centipedes have limited vision; some species have no eyes at all. Those that have eyes can perceive differences in light and dark but lack true vision. Millipedes have a rounded head that, unlike centipedes, is flat only on the bottom. Millipedes have a pair of large mandibles, a pair of antennae, and like centipedes limited vision.
The body of millipedes is cylindrical. Millipedes are detritivores, feeding on detritus such as decomposing vegetation, organic material, and feces, and are prey for a variety of animals including amphibians, reptiles, mammals, birds, and other invertebrates. Millipedes lack the venomous claws of centipedes, so they must curl into a tight coil to protect themselves.
Millipedes generally have 25 to segments. Each thoracic segment has a pair of legs, while the abdominal segments bear two pairs of legs each. Habitat Myriapods inhabit a variety of habitats but are most abundant in forests. They also inhabit grasslands, scrublands, and deserts. Although most myriapods are detritivores, centipedes are not; they are mainly nocturnal predators.
The two less familiar groups of myriapods, the sauropods and the symphylans, are small organisms some are microscopic that live in soil.
Miriápodos: definición, características, alimentación habitat y más.
The head of Scutigera coleoptrata , showing antennae , compound eyes and mouthparts Myriapods have a single pair of antennae and, in most cases, simple eyes. Exceptions include the large and well-developed compound eyes of Scutigera  The mouthparts lie on the underside of the head, with an "epistome" and labrum forming the upper lip, and a pair of maxillae forming the lower lip. A pair of mandibles lie inside the mouth. Myriapods breathe through spiracles that connect to a tracheal system similar to that of insects. There is a long tubular heart that extends through much of the body, but usually few, if any, blood vessels. Although the ventral nerve cord has a ganglion in each segment, the brain is relatively poorly developed. The female lays eggs which hatch as much-shortened versions of the adults, with only a few segments and as few as three pairs of legs.
Miriápodos: características, clasificación, ejemplos de especies