Arthropleuridea Temporal range: Late Silurian - Sakmarian | |
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Arthropleura fossil illustration | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Subphylum: | Myriapoda |
Class: | Diplopoda |
Subclass: | † Arthropleuridea Waterlot, 1934 |
Orders | |
Arthropleuridea is an extinct subclass of myriapod arthropods that flourished during the Carboniferous period, having first arisen during the Silurian, and perishing in the Early Permian. [1] Members are characterized by possessing diplosegement (fused "double segments", as in modern-day millipedes) paranotal tergal lobes separated from the body axis by a suture, and by sclerotized plates buttressing the leg insertions. Despite their unique features, recent phylogenetic research suggests Arthropleuridea be included among millipedes in the class Diplopoda. [2] [3] The subclass contains three recognized orders, each with a single genus. [4]
Arthropleurids lived in the moist coal swamps that were common at the time and may have burrowed in the undergrowth. They were either herbivores or detritivores. Besides their size, their most distinguishing features were their legs with eight segments (as many as 30 pairs) and extremely tough exoskeletons. There is no evidence of spiracles, so the animals must have used lungs or gills for respiration. [3]
Most arthropleurideans are thought to have been terrestrial, although, without any known respiratory structure, terrestriality is assumed only by analogy to modern arthropods. [5] Early forms, however, including Eoarthropleura (order Eoarthropleurida), appear to have been aquatic.[ citation needed ] For this reason, some question Arthropleuridea's inclusion among millipedes because no modern aquatic myriapods are known. [3]
Arthropleuridea is most famous for Arthropleura (order Arthropleurida). Tracks from Arthropleura up to 50 cm wide have been found at Joggins, Nova Scotia. [6] Reaching over 2 meters in length, arthropleurids are among the largest arthropods ever to have lived. The lack of large terrestrial vertebrate predators and the highly oxygenic atmosphere at that time probably enabled them to grow so large. [7] It was previously believed that Arthropleura became extinct as the coal swamps dried out. [3] However, many fossils have been discovered after the Carboniferous rainforest collapse. A more recent proposal is that predation by tetrapods and the aridification of the equator caused it to become extinct. [1] [8] Arthropleura has been found from the Upper Carboniferous of Europe and North America.
Eoarthropleura has been found from the Upper Silurian through the Upper Devonian of Europe and North America. [9]
Microdecemplex , of the order Microdecemplicida, was dwarfed by the other Arthropleurideans, at just a few millimeters long. The genus is known from the Middle through Upper Devonian of New York state, USA. [4]
After several decades of uncertainty, Arthropleuridea was placed within the Diplopoda in the year 2000. [10] However, there is still controversy regarding the relationships of the three orders to living millipede groups. [2] [11] Some authors place Arthropleuridea within the Chilognatha, as a sister group to all living Chilognathan millipedes (Pentazonia + Helminthomorpha). [10] [12] An alternate hypothesis breaks up the subclass: placing the orders Arthropleurida and Eoarthropleurida within the basal Penicillata (as sister to the living Polyxenida), and leaving only Microdecemplicida as a sister group to the living Chilognatha. [13] Under this hypothesis, Arthropleuridea would be paraphyletic.
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 a 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.
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.
Diplichnites are arthropod trackways with two parallel rows of blunt to elongate, closely spaced tracks oriented approximately perpendicularly to the mid-line of the trackway. The term is more often used for the ichnofossils of this description; however, similar trackways from recent arthropods are sometimes given this name as well.
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. These features have inspired the common names bristly millipedes or pincushion millipedes. This order includes about 148 species in four families worldwide, which represent 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.
Maldybulakia is a genus of freshwater arthropod which lived during Late Silurian to Late Devonian. Maldybulakia is known from three species, M. angusi and M. malcolmi from Australia, M. mirabilis from Kazakhstan, and M. saierensis from China. Its classification is uncertain, it was originally described as a myriapod-like animal, and later considered related to the xiphosurans, or an artiopod.