| Brachydesmus | |
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| Brachydesmus superus | |
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| Genus: | Brachydesmus Heller, 1858 |
Brachydesmus is a genus of millipedes belonging to the family Polydesmidae. [1] The Czech zoologist Camill Heller first described this genus to contain the type species B. subterraneus. [2] This genus now includes about 75 described species. [3]
This genus has a Paleactic distribution, [3] with about 70 species in Europe and nearly 80 percent of these European species found in the Balkans. [4] A few species are native to the Caucasus region, Anatolia, Hyrcania, and the Levant. [4] The common species B. superus is especially widespread, found throughout Europe and introduced to the United States, Cape Verde, Madeira, the Azores, and the Canaries. [5] [6]
This genus includes both small and medium-sized polydesmid millipedes. Species in this genus feature little pigmentation or lack pigment altogether. [4] Species may be identified as members of this genus based on the form of their gonopods. [7]
Species in this genus have only 19 segments as adults (counting the collum, the telson, and the rings in between), one fewer than found in most polydesmid species. [5] [8] Accordingly, adults in this genus have two fewer pairs of legs than most polydesmid adults have: Females have only 29 pairs of legs, and males have only 28 pairs of walking legs (excluding the eighth leg pair, which become gonopods). [5] [6] Species in this genus arrive at these lower numbers of legs and segments by going through the first seven stages of teloanamorphosis observed in other polydesmids but reaching maturity one molt earlier, in the seventh stage rather than in an eighth stage, and then mating and dying without another molt. [5] [8]
Species within this genus include: [9]
Glomerida is an order of pill-millipedes found primarily in the Northern Hemisphere. Also known as northern pill millipedes, they superficially resemble pill-bugs or woodlice, and can enroll into a protective ball. They have twelve body segments, 17 to 19 pairs of legs, and males have enlarged rear legs involved in mating. The order includes about 30 genera and at least 280 species, including Glomeris marginata, the common European pill-millipede. The order contains members in Europe, South-east Asia and the Americas from California to Guatemala. Although historically considered closely related with the similar sphaerotheriidans that also enroll, some DNA evidence suggest they may be more closely related to glomeridesmidans, a poorly known order that does not enroll.
Polydesmida is the largest order of millipedes, with more than 5,000 species, including all the millipedes reported to produce hydrogen cyanide (HCN). This order is also the most diverse of the millipede orders in terms of morphology. Millipedes in this order are found in all regions of the world other than Antarctica.
Eutrichodesmus is a genus of millipedes in the family Haplodesmidae, containing at least 32 species in China, Taiwan, and Southeast Asia. One of these species exhibits sexual dimorphism in segments number: The adult females have 20 segments, but the adult males have only 19.
Tridontomidae is a small family of millipedes. Its members are endemic to Guatemala. These millipedes range from 22 mm to 28 mm in length and are uniformly grayish in color; their legs and antennae are unusually long and slender. This family includes the remarkable species Aenigmopus alatus, in which adult males feature no gonopods. This millipede is the only species in the infraclass Helminthomorpha without gonopods.
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.
Chordeumatida is a large order of millipedes containing some 1200 species with a nearly worldwide distribution. Also known as sausage millipedes, they grow and develop through a series of moults, adding segments until they reach a fixed number in the adult stage, which is usually the same for a given sex in a given species, at which point the moulting and the addition of segments and legs stop. This mode of development, known as teloanamorphosis, distinguishes this order from most other orders of millipedes, which usually continue to moult as adults, developing through either euanamorphosis or hemianamorphosis.
Polydesmidae is a family of millipedes in the order Polydesmida. These millipedes range from 4 mm to 30 mm in length. This family includes species notable for featuring sexual dimorphism in segment number: Adult females in the genus Perapolydesmus have the usual 20 segments, but the adult males have only 19.
Glomeridesmidae is a millipede family of the order Glomeridesmida. This family includes two genera: The genus Glomeridesmus includes most species in this family; the genus Glomeridesmoides includes one species.
Fuhrmannodesmidae is a family of millipedes belonging to the order Polydesmida. Although some authorities deem Fuhrmannodesmidae to be a junior synonym for Trichopolydesmidae, others still regard the taxonomic status of Fuhrmannodesmidae as valid. The family Fuhrmannodesmidae includes over 50 genera.
Metopidiotrichidae is a family of millipedes in the order Chordeumatida. These millipedes range from 4 mm to 17 mm in length. Adult millipedes in this family have 32 segments, not the 30 segments usually found in this order. Adult males in this family often feature a reduced or vestigial leg pair 10 as part of the gonopod complex, in addition to the two leg pairs typically modified into gonopods in this order. There are about 9 genera and at least 70 described species in Metopidiotrichidae.
Trichopolydesmidae is a family of millipedes belonging to the order Polydesmida. This family includes two genera notable for featuring sexual dimorphism in segment number: adult females in these genera have the 20 segments usually found in this order, but adult males have only 19. This family also includes the species Deharvengius bedosae, notable for being among the very few species in this order to feature adults with only 18 segments rather than the 20 segments usually found in polydesmids.
Chordeumatidae is a family of millipedes belonging to the order Chordeumatida. These millipedes range from 7 mm to 18 mm in length and are found in Europe. Adult millipedes in this family have either 28 or 30 segments. This family features distinctive sex-linked modifications to the legs in adults: In the adult female, a legless sternite replaces the third pair of legs, and in the adult male, five pairs of legs are modified in the gonopod complex. These modifications are more extensive than those found in other adult males in this order, which often have only two leg pairs modified into gonopods. With the more extensive modifications to the legs in this family, species with the usual 30 segments feature adult females with only 49 leg pairs and adult males with only 45 pairs of walking legs, and species with only 28 segments feature adult females with only 45 leg pairs and adult males with only 41 pairs of walking legs.
Speophilosomatidae is a family of millipedes belonging to the order Chordeumatida. These millipedes are found in Japan and range from 4 mm to 6 mm in length. Adult millipedes in this family are notable for being among the few in this order with only 26 segments instead of the 30 usually found in chordeumatidans. The adult males in this family are also notable for involving three leg pairs in the gonopod complex rather than the two pairs typically modified into gonopods in this order.
Peterjohnsiidae is a small family of millipedes belonging to the order Chordeumatida. The family was first described in 1987 by Jean-Paul Mauriès. These millipedes range from 3 mm to 8 mm in length and are found in Australia. Species in this family exhibit sexual dimorphism in segment number: adult males have 30 segments, but adult females have 32 segments. In adult males in this family, the gonopod complex involves three leg pairs rather than just the two usually modified into gonopods in this order.
Haaseidae is a family of millipedes belonging to the order Chordeumatida. Adult millipedes in this family range from 4.5 mm to 12 mm in length and have either 28 or 30 segments. For example, Orobainosoma hungaricum orientale, a subspecies of Haasea hungarica, has only 28 segments in adults rather than the 30 usually found in chordeumatidan adults, with only 46 pairs of legs in adult females and only 44 pairs of walking legs in adult males.
Golovatchiidae is a family of millipedes belonging to the order Chordeumatida. This family contains a single species, Golovatchia magda. This species ranges from 15 mm to 17 mm in length and is found in the Russian Far East. Adult millipedes of this species have 30 segments. In the adult male of this species, the gonopod complex involves three leg pairs rather than just the two that are usually modified into gonopods this order.
Hoffmaneumatidae is a family of millipedes belonging to the order Chordeumatida. This family includes two genera, one (Hoffmaneuma) found in the Russian Far East and the other (Japanoparvus) found in Japan. Millipedes in this family range from 4 mm to 6 mm in length. Adult millipedes in this family have only 28 segments, not the 30 segments usually found in this order. Adult males in this family feature a reduced leg pair 10 in addition to the two pairs normally modified into gonopods in this order. In the adult male of the species Hoffmaneuma exiguum, for example, the gonopod complex derives from all three leg pairs rather than from just the usual two.
Opisthocheiridae is a family of millipedes belonging to the order Chordeumatida. These millipedes range from 5 mm to 16 mm in length and are found from Belgium to Morocco. Adult millipedes in this family have 26 or 30 segments. This family includes the cave-dwelling species Opisthocheiron canayerensis, notable as one of few chordeumatidan species with only 26 segments. The adult female of this species has only 42 pairs of legs, and the adult male has only 40 leg pairs, as one would expect for adult chordeumatidans with four fewer segments than typically found in this order.
Brachydesmus superus, sometimes called the flat millipede, is a species of millipede in the family Polydesmidae. Its specific name is from the Latin word for "above, upper," because it lives in the upper soil layer.
Agenodesmus is a genus of millipedes in the family Fuhrmannodesmidae, which some authorities consider a junior synonym of Trichopolydesmidae. This genus is notable for being among the very few genera in the order Polydesmida to feature adults with only 18 segments rather than the 20 segments usually found in this order. The genus Agenodesmus contains only two species, A. reticulatus and A. nullus. The type species A. reticulatus is notable as the first polydesmidan millipede discovered with only 18 segments in adults, the smallest number recorded in the order Polydesmida. Before the discovery of A. reticulatus, polydesmidans were known to have only 19 or 20 segments in adults.
