Millipedes are a group of arthropods that are characterised by having two pairs of jointed legs on most body segments; they are known scientifically as the class Diplopoda, the name being derived from this feature. Each double-legged segment is a result of two single segments fused together. Most millipedes have very elongated cylindrical or flattened bodies with more than 20 segments, while pill millipedes are shorter and can roll into a ball. Although the name "millipede" derives from the Latin for "thousand feet", no known species has 1,000; the record of 750 legs belongs to Illacme plenipes. There are approximately 12,000 named species classified into 16 orders and around 140 families, making Diplopoda the largest class of myriapods, an arthropod group which also includes centipedes and other multi-legged creatures.
Myriapoda is a subphylum of arthropods containing millipedes, centipedes, and others. The group contains over 16,000 species, most of which are terrestrial.
Lichida is an order of typically spiny trilobite that lived from the Furongian to the Devonian period. These trilobites usually have 8–13 thoracic segments. Their exoskeletons often have a grainy texture or have wart or spine-like tubercles. Some species are extraordinarily spiny, having spiny thoracic segments that are as long or longer than the entire body, from cephalon (head) to pygidium (tail). The sections of the pygidia are leaf-like in shape and also typically end in spines.
Pill millipedes are any members of two living orders of millipedes, often grouped together into a single superorder, Oniscomorpha. The name Oniscomorpha refers to the millipedes' resemblance to certain woodlice (Oniscidea), also called pillbugs or "roly-polies". However, millipedes and woodlice are not closely related ; rather, this is a case of convergent evolution.
Pneumodesmus newmani is a species of myriapod that lived in the Paleozoic. Its exact age is uncertain; it was originally interpreted as living 428 million years ago, in the Late Silurian; however, subsequent research dates it to around 414 million years old, in the Early Devonian (Lochkovian). It is one of the first myriapods, and among the oldest creatures to have lived on land It was discovered in 2004, and is known from a single specimen from Stonehaven, Aberdeenshire, Scotland.
Euthycarcinoidea are an enigmatic group of extinct possibly amphibious arthropods that ranged from Cambrian to Triassic times. Fossils are known from Europe, North America, Argentina, Australia and Antarctica.
† Bembexia is a genus of fossil sea snails, marine gastropod mollusks. This genus is placed in the subfamily Eotomariinae, of the family Eotomariidae. The shell characters resemble those of Balbinipleura. These snails have been interpreted as herbivorous, probably grazing on algae.
Synziphosurina is a paraphyletic group of chelicerate arthropods previously thought to be basal horseshoe crabs (Xiphosura). It was later identified as a grade compose of various basal euchelicerates, eventually excluded form the monophyletic Xiphosura sensu stricto and only regarded as horseshoe crabs under a broader sense. Synziphosurines survived at least since early Ordovician to early Carboniferous in ages, with most species are known from the in-between Silurian strata.
Entobia is a trace fossil in a hard substrate formed by sponges as a branching network of galleries, often with regular enlargements termed chambers. Apertural canals connect the outer surface of the substrate to the chambers and galleries so the sponge can channel water through its tissues for filter feeding. The fossil ranges from the Devonian to the Recent.
Archipolypoda is an extinct group of millipedes known from fossils in Europe and North America and containing the earliest known land animals. The Archipolypoda was erected by Scudder (1882) but redefined in 2005 with the description of several new species from Scotland. Distinguishing characteristics include relatively large eyes with densely packed ocelli, and modified leg pairs on the 8th body ring. Some species had prominent spines while others had a flattened appearance.
Cyrtospirifer is an extinct genus of brachiopods. The fossils are present in the Middle and Upper Devonian.
Xyloiuloidea is an extinct superfamily of millipedes that existed from the Lower Devonian through the Upper Pennsylvanian period in Europe and North America.
Euphoberiidae is an extinct family of archipolypodan millipedes known from the Upper Pennsylvanian of Europe and North America. The family includes relatively large millipedes measuring up to 30 cm (12 in) long bearing distinctive spines and were the dominant millipedes of the Pennsylvanian.
Pleurojulidae is an extinct family of millipedes known from the Westphalian stage of the upper Carboniferous that are distinct enough to be placed in their own order, Pleurojulida. Fossil pleurojulids up to 10 centimeters long are known from Europe and the United States.
Cowiedesmus is an extinct millipede genus known from the middle Silurian of Scotland, and is one of the earliest known land animals. Cowiedesmus was about 4 cm (1.6 in) long and characterized by a greatly enlarged pair of legs on the 8th segment which may have been used in clasping females or functioned as gonopods. Coweiedesmus is distinct enough from other living and fossil millipedes to be placed in its own order, Cowiedesmida. The only known species, C. eroticopodus, was described in 2004.
Archidesmus is an extinct millipede genus from the Lower Devonian Old Red Sandstone of the United Kingdom. It is the only member of the taxonomic family Archidesmidae. Individuals were up to 5 cm (2.0 in) long, and had 60 to 80 body segments decorated with tubercles (bumps) on the upper surface, and most segments possessed wing-like keels (paranota) extending to the side. The type species Archidesmus macnicoli was described by British paleontologist Benjamin Peach in 1882. A second species, A. loganensis was also described by Peach but its status as a valid species- or even a myriapod- is debated.
Zanclodesmus willetti is an extinct species of archipolypodan millipede that lived in the Late Devonian period of North America, approximately 380 million years ago. It was described in 2005 based on a fossil discovered in the Escuminac Formation of Quebec, Canada two years prior. It was approximately 44 mm (1.7 in) long and 10 mm wide with 27 body segments, and had kidney shaped patches of ocelli. Each trunk segment had long, sickle-shaped extensions (paranota) projecting laterally, and was decorated on the dorsal surface with low rectangular bosses ("bumps") bordered by crescent-shaped bosses. The genus name Zanclodesmus derives from Greek Zanklon, meaning "sickle", in reference to the long, curved paranota, and desmus, a common root word in millipedes. The species name willietti honors Miguasha National Park warden Jason Willett, who discovered the fossil.
Palaeodesmus tuberculata is an extinct species of millipede known from the lower Devonian period of modern day Scotland. It was originally described as "Kampecaris tuberculata" by the Reverend Stanley Graham Brade-Birks, but was placed in its own new genus, Palaeodesmus, in 2004. Palaeodesmus has three rows of tubercles or bosses in the shape of round-edged squares or rectangles on the dorsal portion of each body segment. Palaeodesmus is a member of the extinct group Archipolypoda, but its anatomy is too poorly known to place it confidently within any known taxonomic family or order, and so it remains incertae sedis, although possibly related to archidesmidan species such as Archidesmus.
Juliformia is a taxonomic superorder of millipedes containing three living orders: Julida, Spirobolida, and Spirostreptida, and the extinct group Xyloiuloidea known only from fossils. The species possess long cylindrical bodies with sclerites fused into complete rings. Juliform millipedes possess defensive repugnatorial glands on all body segments except the last few, and are the only known millipedes to produce quinones in their defensive secretions. Juliform males have two pairs of gonopods consisting of the modified 8th and 9th pair of legs: in Julida and Spirobolida the posterior gonopods are primarily involved in sperm-transferring, while in Spirostreptida it is the anterior gonopods. Juliformians also lack Tömösváry organs and have a large collum which overhangs the rear of the head.
Kampecaris is an extinct genus comprising the Kampecarida, an enigmatic group of millipede-like arthropods, from the Silurian and early Devonian periods of Scotland and England. They are among the oldest known land-dwelling animals. They were small, short-bodied animals with three recognizable sections: an oval head divided along the midline, ten limb-bearing segments forming a cylindrical trunk that tapered slightly towards the front, and a characteristic swollen tail formed by a modified segment that tapers at its rear into an "anal segment". The cuticle forming their exoskeletons was thick, heavily calcified, and composed of two layers.
