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 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 tight ball. Although the name "millipede" derives from Latin for "thousand feet", no species was known to have 1,000 or more until the discovery in 2020 of Eumillipes persephone, which can have over 1,300 legs. 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.
Chilognatha is a subclass of the class Diplopoda, which includes the vast majority of extant millipedes, about 12,000 species.
Myriapods are the members of subphylum Myriapoda, containing arthropods such as millipedes and centipedes. The group contains about 13,000 species, all of them terrestrial.
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.
Arthropleura is an extinct genus of massive millipedes that lived in what is now North America and Europe around 345 to 290 million years ago, from the Viséan stage of the lower Carboniferous Period to the Sakmarian stage of the lower Permian Period. The species of the genus are the largest known land invertebrates of all time, and would have had few, if any, predators.
Euphoberia is an extinct genus of millipede from the Pennsylvanian epoch of the Late Carboniferous, measuring up to 15 centimetres (5.9 in) in length, that is small in Euphoberiidae which contains species with length about 30 centimetres (12 in). Fossils have been found in Europe and North America.
Pneumodesmus newmani is a species of myriapod that lived during the late Wenlock epoch of the Silurian period around 428 million years ago. Although a 2017 study dates its occurrence based on zircon data analysis as the Early Devonian (Lochkovian), the 2023 study confirmed the age identification of the 2004 study through palynological, palaeobotanical and ziron analyses incorporating newly discovered additional data. 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.
Eoarthropleura was a genus of millipede-like creatures which lived between the Late Silurian and Late Devonian periods. It reached 100 mm (3.9 in) in length. Fossils, mainly of cuticle fragments, have been found in Europe and North America. It is the earliest known member of the Arthropleuridea, and the oldest known terrestrial animal of North America.
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.
Polyxenida is an order of millipedes readily distinguished by a unique body plan consisting of a soft, non-calcified body ornamented with tufts of bristles – traits that have inspired the common names "bristly millipedes" or "pincushion millipedes". There are at least 86 species in four families worldwide, and are the only living members of the subclass Penicillata.
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.
Zosterogrammidae is an extinct family of millipedes containing three genera, each with a single species. Fossils are known from the Czech Republic, Scotland, and the USA. Zosterogrammidae constitutes the sole family of the order Zosterogrammida.
The Panther Mountain Formation is a geologic formation in New York. It preserves fossils dating back to the Devonian period. It is located in the counties of Albany, Madison, Oneida, Otsego, and Schoharie. It is well known for its fossil arthropods preserved as flattened cuticles, including Attercopus and Dracochela.
Microdecemplex rolfei is the only known species of the extinct, small-bodied millipede order Microdecemplicida, a member of the extinct subclass Arthropleuridea. Fossils, measuring less than 5 mm in length, are known from the Panther Mountain Formation of New York State, dating to the Middle Devonian. This species apparently lacks antennae and shows sexual dimorphism in its hind legs, which may be similar in function to the telopods of male living pill-millipedes that are used to grasp females during mating.
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.
Juliformia is a taxonomic superorder of millipedes containing three living orders: Julida, Spirobolida, and Spirostreptida, and the extinct group Xyloiuloidea known only from fossils.
William Albert Shear is Trinkle Professor Emeritus at Hampden-Sydney College, Virginia. He is a spider and myriapod expert who has published more than 200 scientific articles primarily on harvestman and millipede taxonomy.
Necrogammarus salweyi is the binomial name applied to an arthropod fossil discovered in Herefordshire, England. The fossil represents a fragmentary section of the underside and an appendage of a pterygotid eurypterid, a group of large and predatory aquatic arthropods that lived from the late Silurian to the late Devonian. The Necrogammarus fossil is Late Silurian in age and its generic name means "dead lobster", deriving from Ancient Greek νεκρός and Latin gammarus ("lobster").
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.
