The most obvious feature of millipedes
is the number of legs. The name literally means “thousand feet,” and they are
commonly referred to as “thousand-leggers.” However, this is a figurative term,
as the “leggiest” millipede (also the leggiest animal), Illacme plenipes
(order Siphonophorida, family Siphonorhinidae), occurring in San Benito County,
California, USA, has only 750 legs (375 pairs) (Cook & Loomis 1928, Shelley
1996, Shelley & Hoffman 2004). It would have to grow by another one-third (33%)
and add 63 segments, carrying 252 legs (126 pairs), to become a true
“thousand-legger” and a “millipede” in the literal sense.
Diversity and ecology
The Diplopoda encompasses a
mind-boggling diversity of forms. Approximately 7,000 species have been
described from a global fauna that is estimated, based on known degrees of
endemism, to contain around 80,000 species, and we know very little about the
fauna of China, which may really be immense. Millipedes are among the most
ancient surviving terrestrial arthropod groups; some of the oldest fossils of
land animals are diplopods, and modern forms had differentiated by the late
Silurian period of the Paleozoic era, ca. 410 million years ago (Almond 1985,
Shear 1992). While inhabiting all subarctic environments including deserts, they
lack a waxy cuticle on the exoskeleton to function as a dessication barrier, and
thus occur primarily in moist, deciduous habitats. With few exceptions,
millipedes are exclusively “detritivores” (feed on decaying plant material or
“detritus”) and are adapted for burrowing in the substrate, where they fill an
important ecological niche by fragmenting accumulated detritus, thereby
facilitating microbial decomposition and soil nutrient cycles. In tropical and
subtropical forests, where earthworm populations are low, millipedes are the
main debris-reducing, soil-forming organisms.
Body forms, coloration, and bioluminescence
Millipedes are relatively inflexible,
“progoneate” arthropods (reproductive tracts open near the anterior end of the
body) with two body divisions, a head and trunk. In most orders, the species
possess a row of “ozopores” laterally, the openings of the defensive glands from
which noxious or toxic fluids are secreted that repel predators, this being
millipedes’ primary method of defense. They exhibit a great array of body forms
that are superimposed on a basic cylindrical pattern. Many species, particularly
in the orders Polydesmida and Platydesmida, possess lateral expansions of the
dorsum called “paranota” that increase the surface area and impart a flattened
appearance to the organism, hence the term “flat-backed” millipedes. Some
species have developed the ability to volvate into a perfect ball or sphere, and
are convergent in this regard with the oniscoid Isopoda of the class Crustacea
that have been introduced into North America and are common in urban
environments. Some millipedes are dorsolaterally smooth while others are
ornamented to varying degrees, some elaborately so, with papillae, lobes,
pustules, tubercles, ridges, crests, spines, and other projections;
additionally, the paranota can be notched, indented, and modified to the point
that they become spiniform in shape. Similarly, some species are brown or gray
in color while others exhibit vivid “aposematic” coloration (colors warning
about the defensive secretions) with red, orange, yellow, blue, purple, and
white spots and/or transverse or longitudinal stripes; still others are
uniformly reddish or turquoise. In Tulare, Kern, and Los Angeles counties,
California, the species of Motyxia
(Polydesmida: Xystodesmidae) bioluminesce. The entire animal lights up at night
in a continuous, neon-white glow. These are the world’s only bioluminescent
millipedes, and the phenomenon is thought to function as “warning luminescence,”
a nocturnal equivalent of aposematic coloration. The glowing millipedes are
conspicuous at night in the southern Sierra Nevada and have been described as
“resembling the starry sky on a dark night.”
The class Diplopoda is defined by
three autapomorphies (unique derived features): aflagellate spermatozoa, the
presence of four or more apical sensory cones on each antenna, and the
diplosegment condition. In the last, adjacent body somites, each carrying a pair
of legs, tracheal (respiratory) openings, and a ventral nerve cord ganglion,
become fused within the embryo to form diplosomites. The structures associated
with the anterior of the fused somites have become relocated to the posterior
somite such that in the resulting diplosegment (henceforth referred to as just
“segment”), all four legs and tracheal openings and both ganglia are located in
the metazonite (representing the posterior of the fused somites), while the
prozonite (representing the anterior of the fused somites) lacks structures and
thus inserts inside the preceding metazonite, which allows for a telescoping of
segments and a more compact body form. The diplosegment condition is believed to
have evolved in conjunction with millipedes’ burrowing habits, as the pushing
force is more efficiently transmitted to the pushing surface when alternate
segmental joints are made rigid and incompressible. The power for this pushing
is generated by the legs, and at any point in time, most are in contact with the
substrate in varying stages of the backstroke, pushing the millipede slowly and
inexorably forward. The appendages arise midventrally, which allows for the
longest possible legs and the greatest power with the least lateral extension,
thereby minimizing the possibility that the appendages will extend appreciably
beyond the sides of the body, where they are likely to be damaged or broken in
the narrow spaces that millipedes inhabit.
Burrowing life styles
Three burrowing mechanisms are known
for millipedes. The first is bulldozing, in which the millipede lowers
its head and rams straight ahead, with the “collum” or 1st segment constituting
the pushing surface; this method is employed by the “juliform,” or
rounded/cylindrical millipedes, and involves most representatives of the orders
Julida, Spirobolida, and Spirostreptida. The second is wedging, in which
the anterior end inserts into a crack or crevice, and the legs, by pushing
upwards and straightening, cause the opening to widen, thus allowing further
penetration by the anterior end. This method is employed by the flat-backed
millipedes, primarily representatives of the order Polydesmida; the paranota
constitute the pushing surface and tend to split matter in a horizontal plane,
like matted layers of leaves. The third mechanism is boring, in which
segments of progressively greater width are dragged forward thereby widening a
crevice and allowing further penetration. This method is exhibited by forms in
which the anterior end is narrow and the next several segments become
progressively wider, as in the order Polyzoniida. Additionally, some millipedes
are believed to have undergone “habit reversal,” and abandoned burrowing
for a different lifestyle. We know they evolved as burrowers because they’re
millipedes and possess the diplosegment condition that evolved in conjunction
with burrowing, but they no longer burrow, or do so only infrequently or feebly,
and now exhibit a different lifestyle. Some, like representatives of the order
Callipodida, tend to be surface active and relatively quick (quick for
millipedes), and not surprisingly, such species exhibit a higher instance of
carnivory than most millipedes. Effective burrowing is also believed to be
possible only within certain size limits. Thus, small, narrow-bodied (<1.0
mm wide) representatives of families like the Blaniulidae (order Julida) are too
weak to burrow effectively and inhabit existing cracks and crevices instead. The
largest millipedes, those upwards of 30 cm (1 ft.) in length, also tend to be
surface active because too great an amount of force would be needed for so large
and bulky an animal to burrow an opening. Consequently, videos of savannas and
deserts in eastern and southern Africa sometimes show species of the genus
(Spirostreptida: Spirostreptidae), the largest known millipedes, wandering
across the grassy and sandy surfaces.
Diversity in North America
The extant representatives of the
class Diplopoda presently comprise 2 subclasses, 16 orders, and 145 families.
Fifty-two families and ca. 914 described species inhabit the US and Canada, but
the Parajulidae (order Julida), the largest family on the continent, is
essentially unstudied, and some 200 undiscovered species are anticipated in this
taxon alone. The higher taxa (subfamilies and orders) are distinguished
primarily by aspects of the exoskeleton, the number of legs and segments, the
profile and general body form, the configuration of the head, and the presence
or absence, and position when present, of the sperm transfer or copulatory
appendages in males.
The subclasses Penicillata & Chilognatha; the infraclass Pentazonia
The subclass Penicillata, with 160
known species (Nguyen Duy-Jacquemin & Geoffroy 2003), comprises forms in which
the exoskeleton is soft, non-calcified, and covered with tufts of modified setae
or bristles; males lack copulatory appendages, and reproduction occurs without
contact between the sexes. Penicillates have a mechanical, rather than chemical,
defense mechanism to thwart predation. The caudal bristles have apical hooks and
barbs along their lengths by which they interconnect; when attacked by ants,
these bristles detach, entangling and disengaging the predators, which become
hopelessly entangled the more they struggle until they die (Eisner et
al. 1996). All other millipedes belong to the subclass Chilognatha, which
possesses a hard, calcified exoskeleton with at most only scattered setae. Males
also possess reproductive appendages that are modified and specialized walking
legs, and reproduction involves contact between the sexes. The infraclass
Pentazonia, comprising three orders based primarily on the number of segments
and whether or not the organisms volvate, contains relatively short, broad
millipedes in which the five segmental sclerites (a dorsal tergite, ventral
sternite, and two lateral pleurites) are separate and loosely connected by
membrane. The last pair of appendages in males is modified into structures
called “telopods” that either directly transfer the spermatophore to the
female’s openings or function to clasp females during mating. Aspects of the
configurations of the telopods constitute the primary taxonomic characters at
the generic and specific levels.
The infraclass Helminthomorpha
The remaining 12 orders, containing
the vast majority of species, belong to the infraclass Helminthomorpha, which
comprise elongate, worm-like millipedes with varying degrees of fusion among the
segmental sclerites that culminate in the condition in the Polydesmida in which
they coalesce into a complete ring with no evidence of suture lines. In males,
either the anterior or both pairs of legs on segment 7 (subterclass Eugnatha),
or the posterior legs on segment 7 and the anterior pair on segment 8 (subterclass
Colobognatha), are modified into copulatory appendages called “gonopods.” As in
the Pentazonia, aspects of the configurations of the gonopods are the primary
taxonomic characters at the generic and specific levels, so males are usually
necessary for determinations below the familial level. Representatives of the
subterclass Colobognatha have triangular or pointed heads with relatively long
mouthparts that culminate in the family Siphonophoridae (order Siphonophorida),
in which they are prolonged into a pointed, tubular “beak” or “rostrum,” which
they are believed to insert into plant roots; some platydesmids are thought to
feed on fungi using sucking mouthparts. Representatives of the subterclass
Eugnatha possess chewing mouthparts and strong mandibles with which they crush
detritus into small pieces. Eugnathan families are grouped into superorders
based on general body form, the degree of fusion among the segmental sclerites,
and the positions of gonopods in males. However, this generally accepted
arrangement, detailed by Hoffman (1980) and Shelley (2003), was recently
questioned by Shear et
al. (2003), who provided evidence to suggest that some posterior gonopods
(replacing the 9th legs or the posterior pair on segment 7) aren’t true gonopods
but are modified legs that are shortened so as not to interfere with the
copulatory function of the 8th legs. They further suggested that an unnamed
clade exists in the Eugnatha comprising taxa in which the gonopods arise solely
from the 8th legs (the anterior legs on segment 7), which, if confirmed by
further research, will alter the existing taxonomy and probably also the order
Spirostreptida. Diplopod taxonomy is thus a fluid science, and changes are to be
expected based on new discoveries and reinterpretations of existing knowledge.
Millipedes and humans
Non-scientists are understandably
concerned about whether organisms can harm people or pets, and it is important
to note that, unlike centipedes, millipedes are harmless if handled properly, as
they lack structures to bite, pinch, or sting. Obviously, they should not be
bitten or eaten, as the defensive secretions consist of noxious compounds that
would cause problems if ingested. Some secretions can discolor skin, but this
wears away after a few days without lasting effect; others, however,
particularly from large “juliforms,” can be quite caustic and cause skin
lesions. Some large, juliform, tropical species, particularly in the Americas,
forcefully expel or “squirt” their defensive secretions a meter or so (2-3 feet)
and can blind chickens and dogs. Persons in the Neotropics should therefore be
cautious in handling such millipedes, because these fluids are particularly
caustic and very painful if squirted into the eyes. The collector of
Haitobolus lethifer (Spirobolida: Rhinocricidae) in Haiti, was zapped in his
left eye and experienced instantaneous, intense pain despite bathing it
repeatedly in water; the eyelid and cheek swelled rapidly, closing the eye. The
next day the eyelid was still swollen shut, but the swelling was reduced by
bathing the eye in ice water. On the third day, the skin of the cheek, forehead,
and eyelid turned dark brown and blistered where the spray concentration was
greatest; the blisters persisted for a week after which the discolored skin
peeled off without leaving any scars (Loomis, 1936:70-71).
The importance of taxonomic research
In any ecological or physiological
study, it is essential to know the organism being investigated to ensure that
the same species is employed throughout a study. Appreciation of the ecological
importance of a group of organisms is directly proportional to the understanding
of its taxonomy, which has advanced to the level at which broadly based
biological research is feasible in only a few millipede families. Many species
and genera are superficially similar such that only an experienced taxonomist
can distinguish one from another, and many taxonomically complex and speciose
families are uninvestigated and unavailable for other research. The Parajulidae
is a classical example. It is the dominant North American family, ranging from
southern Alaska and northern British Columbia-Québec to the Florida Keys and
Guatemala, and exhibits a “trans-Beringian” connection with one species in Japan
and China. The Parajulidae is also the dominant, and in many areas the only,
representative in grassland habitats in the Central Plains, where they occur in
association with decaying logs, under dung, and among whatever shelter is
available. Consequently, one can reasonably conclude that parajulids are vital
to the health of prairie ecosystems, but the nascent state of their taxonomy
precludes their utilization in ecological research. Advancing parajulid taxonomy
and opening up the family for other studies is a major research objective for
the next decade.
Family-level Classification (from
The class Diplopoda
consists of 2 subclasses, 16 orders, and 145 families. Fifty-three families,
comprising some 217 genera and 915 nominal species, occur in North America (=the
US and Canada), but hundreds more await description particularly in the families
Glomeridae (Glomerida); Parajulidae (Julida); Atopetholidae (Spirobolida);
Cleidogonidae, Trichopetalidae, and Striariidae (Chordeumatida); and
Polydesmidae & Nearctodesmidae (Polydesmida). Of these 52 families, 39 are
indigenous (17 being endemic), 5 are wholly introduced, and 5 contain both
native and allochthonous species. As the Diplopoda is more speciose than the
Chilopoda, the taxonomy is more complex, and additional categories are required:
Infraclass, Subterclass, and Infraorders in the Polydesmida: Polydesmidea.
Families represented in North America are in bold and preceded by asterisks (*);
"END." denotes an endemic family, "INT." one that is wholly
introduced, and "N-I" one with both native and introduced species.
Class Diplopoda de Blainville in Gervais, 1844
Subclass Penicillata Latreille, 1831
Order Polyxenida Verhoeff, 1934
Superfamily Polyxenoidea Lucas, 1840
Family Hypogexenidae Schubart, 1947
Family Lophoproctidae Silvestri, 1897
*Family Polyxenidae Lucas, 1840
Superfamily Synxenoidea Silvestri, 1923
Family Synxenidae Silvestri, 1923
Subclass Chilognatha Latreille, 1802/1803
Infraclass Pentazonia Brandt, 1833
Limacomorpha Pocock, 1894
Order Glomeridesmida Cook, 1895
Family Glomeridesmidae Latzel, 1884
Oniscomorpha Pocock, 1887
Order Glomerida Brandt, 1833
Family Doderiidae Silvestri, 1904
*Family Glomeridae Leach, 1815
Family Glomeridellidae Cook, 1896
Order Sphaerotheriida Brandt, 1833
Family Sphaerotheriidae C. L. Koch, 1847
Family Zephroniidae Gray in Jones, 1843
Infraclass Helminthomorpha Pocock, 1887
Subterclass Colobognatha Brandt, 1834
Order Platydesmida Cook, 1895
*Family Andrognathidae Cope, 1869
Family Platydesmidae DeSaussure, 1860
Order Polyzoniida Cook, 1895
*Family Hirudisomatidae Silvestri, 1896
*Family Polyzoniidae Newport, 1844
*Family Siphonotidae Cook, 1895 INT.
Order Siphonocryptida Cook, 1895
Family Siphonocryptidae Pocock, 1894
Order Siphonophorida Hoffman, 1980
*Family Siphonophoridae Newport, 1844
*Family Siphonorhinidae Cook, 1895
Subterclass Eugnatha Attems, 1898
Juliformia Attems, 1926
Order Julida Brandt, 1833
Superfamily Blaniuloidea C. L. Koch, 1847
*Family Blaniulidae C. L. Koch, 1847 N-I
Family Galliobatidae Brolemann, 1921
Family Okeanobatidae Verhoeff, 1942
*Family Zosteractinidae Loomis, 1943 END.
Superfamily Juloidea Leach, 1814
*Family Julidae Leach, 1814 INT.
Family Rhopaloiulidae Attems, 1926
Family Trichoblaniulidae Verhoeff, 1911
Family Trichonemasomatidae Enghoff, 1991
Superfamily Nemasomatoidea Bollman, 1893
*Family Chelojulidae Enghoff, 1991 END.
*Family Nemasomatidae Bollman, 1893 N-I
Family Pseudonemasomatidae Enghoff, 1991
*Family Telsonemasomatidae Enghoff, 1991 END.
Superfamily Paeromopodoidea Cook, 1895
*Family Aprosphylosomatidae Hoffman, 1961
*Family Paeromopodidae Cook, 1895 END.
Superfamily Parajuloidea Bollman, 1893
Family Mongoliulidae Pocock, 1903
*Family Parajulidae Bollman, 1893
Order Spirobolida Cook, 1895
Suborder Spirobolidea Cook, 1895
*Family Allopocockiidae Keeton, 1960
*Family Atopetholidae Chamberlin, 1918
*Family Floridobolidae Keeton, 1959 END.
Family Hoffmanobolidae Shelley, 2001
Family Messicobolidae Loomis, 1968
Family Pseudospirobolellidae Brölemann, 1913
*Family Rhinocricidae Brölemann, 1913 INT.
Family Spirobolellidae Brölemann, 1913
Suborder Sinocallipodidea Shear, 2000
*Family Spirobolidae Bollman, 1893
Family Typhlobolellidae Hoffman, 1969
Suborder Trigoniulidea Brölemann, 1913
Family Pachybolidae Cook, 1897
*Family Trigoniulidae Attems, 1909 INT.
Order Spirostreptida Brandt, 1833
Suborder Cambalidea Cook, 1895
*Family Cambalidae Bollman, 1893
Family Cambalopsidae Cook, 1895
Family Glyphiulidae Chamberlin, 1922
Family Pericambalidae Silvestri, 1909
Suborder Epinannolenidea Chamberlin, 1922
*Family Choctellidae Chamberlin & Hoffman, 1950
Family Iulomorphidae Verhoeff, 1924
Family Pseudonannolenidae Silvestri, 1895
Suborder Spirostreptidea Brandt, 1833
Superfamily Odontopygoidea Attems, 1909
Family Atopogestidae Hoffman, 1980
Family Odontopygidae Attems, 1909
Superfamily Spirostreptoidea Pocock, 1894
Family Adiaphorostreptidae Hoffman, 1977
Family Harpagophoridae Attems, 1909
*Family Spirostreptidae Pocock, 1894
Nematophora Verhoeff, 1913
Order Callipodida Pocock, 1894
Suborder Callipodidea Pocock, 1894
Family Callipodidae Bollman, 1893
Suborder Schizopetalidea Hoffman, 1973
*Family Abacionidae Shelley, 1979
Family Caspiopetalidae Lohmander, 1931
Family Dorypetalidae Verhoeff, 1900
Family Paracortinidae Wang & Zhang, 1993
*Family Schizopetalidae Verhoeff, 1909
Family Sinocallipodidae Zhang, 1993
Order Chordeumatida Pocock, 1894
Suborder Chordeumatidea Pocock, 1894
Superfamily Chordeumatoidea C. L. Koch, 1847
Family Chordeumatidae C. L. Koch, 1847
?Family Speophilosomatidae Takakuwa, 1949
Suborder Craspedosomatidea Cook, 1895
Superfamily Anthroleucosomatoidea Verhoeff, 1899
*Family Anthroleucosomatidae Verhoeff, 1899
Family Haasiidae Hoffman, 1980
Family Origmatogonidae Verhoeff, 1914
Family Vandeleumatidae Mauriès, 1970
Superfamily Brannerioidea Cook, 1896
Family Brachychaeteumatidae Verhoeff, 1911
*Family Branneriidae Cook, 1896 END.
Family Chamaesomatidae Verhoeff, 1913
Family Golovatchiidae Shear, 1992
Family Heterolatzeliidae Verhoeff, 1899
Family Kashmireumatidae Mauriès, 1982
*Family Microlympiidae Shear & Leonard, 2003
Family Macrochaeteumatidae Verhoeff, 1914
Family Niponiosomatidae Verhoeff, 1941
*Family Tingupidae Loomis, 1966 END.
Family Trachygonidae Cook, 1896
Superfamily Cleidogonoidea Cook, 1896
Family Biokoviellidae Mršic, 1992
*Family Cleidogonidae Cook, 1896
Family Entomobielziidae Verhoeff, 1899
Family Lusitaniosomatidae Schubart, 1953
Family Opisthocheiridae Ribaut, 1913
*Family Trichopetalidae Verhoeff, 1914
Superfamily Craspedosomatoidea Gray in Jones, 1843
Family Attemsiidae Verhoeff, 1899
*Family Craspedosomatidae Gray in Jones, 1843
Family Haplobainosomatidae Verhoeff, 1909
Superfamily Haaseoidea Attems, 1899
Family Haaseidae Attems, 1899
Superfamily Mastigophorophylloidea Verhoeff, 1899
Family Altajellidae Mikhaljova & Golovatch, 2001
Family Hoffmaneumatidae Golovatch, 1978
Family Mastigophorophyllidae Verhoeff, 1899
Superfamily Neoatractosomatoidea Verhoeff, 1901
Family Neoatractosomatidae Verhoeff, 1901
Superfamily Verhoeffioidea Verhoeff, 1899
Family Verhoeffiidae Verhoeff, 1899
Suborder Heterochordeumatidea Shear, 2000
Superfamily Conotyloidea Cook, 1896
*Family Adritylidae Shear, 1971 END.
*Family Conotylidae Cook, 1896
Superfamily Diplomaragnoidea Attems, 1907
Family Diplomaragnidae Attems, 1907
Superfamily Heterochordeumatoidea Pocock, 1894
Family Eudigonidae Verhoeff, 1914
Family Heterochordeumatidae Pocock, 1894
Family Megalotylidae Golovatch, 1978
Family Metopidiotrichidae Attems, 1907
?Family Peterjohnsiidae Mauriès, 1987
Superfamily Pygmaeosomatoidea Carl, 1941
Family Lankasomatidae Mauriès, 1978
Family Pygmaeosomatidae Carl, 1941
Suborder Striariidea Cook, 1896
Superfamily Caseyoidea Verhoeff, 1909
*Family Caseyidae Verhoeff, 1909
*Family Urochordeumatidae Silvestri, 1909
Superfamily Striarioidea Bollman, 1893
*Family Apterouridae Loomis, 1966 END.
*Family Rhiscosomididae Silvestri, 1909 END.
*Family Striariidae Bollman, 1893 END.
Order Stemmiulida Cook, 1895
Family Stemmiulidae Pocock, 1894
Merocheta Cook, 1895
Order Polydesmida Pocock, 1887
Suborder Leptodesmidea Brölemann, 1916
Superfamily Chelodesmoidea Cook, 1895
Family Chelodesmidae Cook, 1895
Superfamily Platyrhacoidea Pocock, 1895
Family Aphelidesmidae Brölemann, 1916
Family Platyrhacidae Pocock, 1895
Superfamily Rhachodesmoidea Carl, 1903
Family Rhachodesmidae Carl, 1903
Family Tridontomidae Loomis & Hoffman, 1962
Superfamily Sphaeriodesmoidea Humbert & DeSaussure, 1869
Family Campodesmidae Cook, 1896
Family Holistophallidae Silvestri, 1909
*Family Sphaeriodesmidae Humbert & DeSaussure, 1869
Superfamily Xystodesmoidea Cook, 1895
*Family Eurymerodesmidae Causey, 1951 END.
*Family Euryuridae Pocock, 1909 END.
Family Gomphodesmidae Cook, 1896
Family Oxydesmidae Cook, 1895
*Family Xystodesmidae Cook, 1895
Suborder Dalodesmidea Hoffman, 1980
Family Dalodesmidae Cook, 1896
Family Vaalogonopodidae Verhoeff, 1940
Suborder Strongylosomatidea Brölemann, 1916
*Family Paradoxosomatidae Daday, 1889 INT.
Suborder Polydesmidea Pocock, 1887
Infraorder Oniscodesmoides Simonsen, 1990
Superfamily Oniscodesmoidea DeSaussure, 1860
Family Dorsoporidae Loomis, 1958
Family Oniscodesmidae DeSaussure, 1860
Superfamily Pyrgodesmoidea Silvestri, 1896
Family Ammodesmidae Cook, 1896
Family Cyrtodesmidae Cook, 1896
*Family Pyrgodesmidae Silvestri, 1896 N-I
Infraorder Polydesmoides Pocock, 1887
Superfamily Haplodesmoidea Cook, 1895
Family Doratodesmidae Cook, 1896
*Family Haplodesmidae Cook, 1895 INT.
Superfamily Opisotretoidea Hoffman, 1980
Family Opisotretidae Hoffman, 1980
Superfamily Polydesmoidea Leach, 1815
Family Cryptodesmidae Karsch, 1880
*Family Polydesmidae Leach, 1815 N-I
Superfamily Trichopolydesmoidea Verhoeff, 1910
Family Fuhrmannodesmidae Brölemann, 1916
*Family Macrosternodesmidae Brölemann, 1916 N-I
*Family Nearctodesmidae Chamberlin & Hoffman, 1950 END
Family Trichopolydesmidae Verhoeff, 1910
Helminthomorpha incertae sedis
Order Siphoniulida Cook, 1895
Family Siphoniulidae Pocock, 1894
While some genera and
species have been proposed for forms in other regions of the world, the
objective of my faunistic and alpha taxonomic research for over 35 years has
been the elucidation of the North American (NA) diplopod fauna. This primarily
covers taxa in the United States and Canada, but some extend southward into
Mexico. It is divided into five categories, two being complete or nearly so,
which are described briefly below along with future research plans.
The initial emphasis was
the Xystodesmidae (Polydesmida), which occurs in the following regions of NA
plus ones in Asia and the Mediterranean coast of Europe, Africa, and the Middle
East: the eastern US and southern Ontario & Québec, Canada, east of the Central
Plains (the "eastern" fauna); from southern Texas and New Mexico to El Salvador
(the "meso-American" fauna); and along the Pacific Coast from Los Angeles to
southern Alaska, with a disjunct area in eastern Oregon & Washington, northern
Idaho, western Montana, and doubtlessly also adjacent British Columbia (the
"western" fauna)(Fig. 1). This work proceeded in two stages and was built upon
the foundation laid by Dr. R. L. Hoffman, Virginia Museum of Natural History, in
numerous revisionary studies. From 1971-1987, the focus was the “eastern” taxa,
during which the phenomenon of “mosaic complexes” was discovered and addressed
as part of a revision of the genera Sigmoria and Deltotaria
(Shelley & Whitehead 1986); from 1989-1997, the focus was the “western” taxa and
those in Texas and New Mexico. A total of 11 new genera and 83 species &
subspecies were described throughout NA and 15 established genera were revised,
such that today the entire, known US and Canadian fauna has been reviewed except
for two widespread “eastern” genera --
Nannaria and Apheloria -– and a work detailing the overall
distribution of Apheloria and occurrences west of the Mississippi River
is in press (Shelley & McAllister in press)
Fig. 1. Distribution of the Xystodesmidae in North and Central America
This complex family
occurs in the southeast and extends westward into central Texas and Oklahoma,
and northward to Nebraska (Fig. 2). With only one genus and 28 species and
subspecies, it is the dominant representative of the order Polydesmida in
prairie ecosystems in the Central Plains. The Eurymerodesmidae belongs to the
Leptodesmidea, as does the Xystodesmidae and a dozen other families, but its
affinities are uncertain; it exhibits a host of autapomorphies but no clear
synapomorphies with another taxon. Another mosaic complex, its study provided
the opportunity to examine the extent of this phenomenon throughout the
Diplopoda as a whole (Shelley 1990a).
Fig. 2. Distribution of the Eurymerodesmidae
Revisions and Synoptic Studies of Other Orders and Families.
While the research on
the Xystodesmidae and the Eurymerodesmidae was in progress, studies were also
proceeding on other NA taxa to advance the goal of documenting the continental
fauna. They have involved every indigenous order in North America except
Polyxenida and Glomerida. The entire Western Hemisphere faunas of the
order Callipodida, family Paeromopodidae (Julida), and subfamily Desmoninae (Polydesmida:
Sphaeriodesmidae) have been studied, and the orders Siphonophorida and
Polyzoniida have been revised to the extents possible today. Though incompletely
reviewed, two polydesmidan families – Nearctodesmidae and Pyrgodesmidae – and
one in the order Chordeumatida (Caseyidae) have been examined in depth as have
the tribe Aniulini (Julida: Parajulidae) and the representatives of the
Polydesmidae occurring west of the Continental Divide. The following additional
genera have also been revised: Anelus (Spirobolida: Allopocockiidae),
Onychelus and Piedolus (Spirobolida: Atopetholidae), Cambala (Spirostreptida:
Cambalidae), Auturus (Polydesmida: Euryuridae), and Brachycybe (Platydesmida:
It is important to
consolidate information from disparate taxonomic studies so that others can
grasp total faunas and the scope of the taxa that exist in the field. This
category includes detailed faunistic studies with anatomical, habitat, and other
information on each species, and “annotated checklists,” which are basically
taxonomic lists with a modicum of additional information. Faunistic studies have
been published on the eastern Piedmont and Kings Mountain regions of North
Carolina (Shelley 1978a, Filka & Shelley 1980) and Canada (the eastern, western,
and central regions and the country as a whole) (Shelley 1988, 1990b, 2002a;
Shelley & LeSage 1989). Checklists have been prepared for the Coastal Zone of
South Carolina, North Carolina as a whole, Florida, and California (Shelley
1978b, 2000a, 2001a, 2002b).
Field work in North
America by myself and colleagues has yielded innumerable samples of relatively
common & abundant indigenous millipedes from areas where there were few if any
records. Existing distributional concepts are thus obsolete, and works have been
published updating them. These include publications on Scytonotus granulatus
(Polydesmida: Polydesmidae), Narceus (Spirobolida: Spirobolidae),
Virgoiulus minutus (Julida, Blaniulidae), the only indigenous blaniulid,
Brachycybe (Platydesmida: Andrognathidae), Apheloria (Polydesmida:
Xystodesmidae), and Opiona columbiana (Chordeumatida: Caseyidae); one is
planned on Aniulus garius (Julida: Parajulidae), and others will develop
as material becomes available (McAllister et al. 2005, Shelley &
McAllister 2006; Shelley et al. 2005a, b, c, 2006, in press).
Outside the NA focus,
species and genera of particular interest have been described or redescribed in
the following orders and families: the polydesmidan families Paradoxosomatidae
(a form from Namibia), Chelodesmidae (forms from Ecuador, Peru, Colombia,
Trinidad and Tobago, and the Bahamas), Platyrhacidae (a species ranging from
Nicaragua to Panama), and Rhachodesmidae and Pyrgodesmidae (both for species in
Mexico) and the polyzoniidan family Hirudisomatidae (Mexico and Nepal);
additionally, the new spirobolidan family Hoffmanobolidae was proposed for a
form in Mexico. Through collaborations with colleagues, the first male in the
order Siphoniulida has been characterized, this being the most poorly known and
rarest order in the class (Sierwald et al. 2003); the suborder
Sinocallipodidea (Callipodida) also has been addressed (Shear et al.
2003) as has the lone African representative of the order Siphonophorida
(Shelley & Hoffman 2004). At the request of colleagues at the Bishop Museum,
Honolulu, seven papers were developed on the Hawaiian fauna, most of which is
introduced (Shelley 1998a-d, Shelley & Swift 1998, Shelley et al. 1998, Shelley
& Golovatch 2000); the only known elements of the Hawaiian fauna that have not
been treated are the representatives of the introduced family Spirobolellidae (Spirobolida)
and the indigenous genus Nannolene (Spirostreptida: Cambalidae). As
exotic millipedes receive little attention in general, works were produced on
introduced representatives of the family Paradoxosomatidae (Polydesmida) on
Pacific Islands and two species in the family Trigoniulidae (Spirobolida) that
have been introduced to islands throughout the world and also to Africa and
North, South, & Central America (Shelley 1998e, Shelley & Lehtinen 1999, Shelley
et al. 2006). The most important efforts were geared toward advancing
Diplopodology in general. I led a collaborative effort to prepare a second
generic and familial Nomenclator (Shelley et al. 2000) and
individually developed a new family-level classification for the class (Shelley
2003); a third "Nomenclator" is in preparation.
effort that warrants mention here is the popularized booklet on centipedes and
millipedes (Shelley 1999), produced for the same reason as this website, to
disseminate accurate information on these arthropods to non-biologists.
Booklets are available from me for free.
faunistic, and distributional research will focus on five main topics, though
other activities may arise. Results, updates, and new information will be
presented periodically on this web site.
The major focus for the
next decade will be the family Parajulidae (Julida), the dominant, most
taxonomically complex NA family that has largely been ignored; there is also one
species in Asia (Japan & China), so it exhibits a “trans-Beringian connection.”
The Parajulidae may contain upwards of 200 undescribed species, and it is the
only indigenous family that occurs in Alaska and every county, state, and
physiographic province in the lower 48 states; in Canada, it extends from the
Queen Charlotte and Vancouver Islands, British Columbia, to southeastern Québec.
North-south, the family ranges from Yakutat, Alaska and James Bay, Ontario, to
Guatemala (Fig. 3). Advancing the knowledge and taxonomy of this family is vital
to the goal of documenting the continental diplopod fauna as a whole. The
initial emphasis has been on the tribe Aniulini, which ranges from the Atlantic
Coast to Arizona, Alberta, and Québec; five papers have been published (Shelley
2000b-c, 2001b, 2002c, 2004) in which 15 species and subspecies have been
described, and a summary one is in preparation. Beyond this tribe, the plan is
to work generally from east to west across the continent revising genera and
tribes in the process. Recently, the new tribe Nesoressini was proposed for
Nesoressa crawfordi, a monotypic new genus & species that occurs primarily
at high elevations on isolated mountains in central New Mexico (Shelley &
Medrano 2006), and a new genus is being proposed for a new form in Florida
(Shelley, in submission).
Fig. 3. Distribution of the Parajulidae in North and Central America
Phreatodesmus, Tidesmus, and Oodedesmus have been erected for
small-bodied polydesmidans that occur around springs and in transiently moist
spots in southwestern deserts (usually during cool weather seasons). They and
undiagnosed genera display diagnostic features of the families Nearctodesmidae &
Macrosternodesmidae, and may link with the form in Jalisco & Colima, Mexico,
that Shelley (1994) assigned to the Nearctodesmidae. A related form with a
strong, pungent aroma, Leonardesmus injucundus
Shelley & Shear, 2006, has recently been described from the Olympic Peninsula of
Ordinal Distributions and Mappings.
In the study on the
Sinocallipodidea, Shear et al. (2003) presented a full
distribution map of the order Callipodida. Comparable efforts are in progress
for the other 15 orders.
Fauna of the “Ark-La-Tex” Region.
since 2001 with C. T. McAllister in Texas has greatly enhanced knowledge of the
fauna of the region containing Arkansas, Louisiana, Texas, and Oklahoma. It has
also significantly advanced faunal knowledge of the area between the Mississippi
River and the Central Plains, where distributions are typically poorly
documented. One new species, Abacion wilhelminae (Callipodida:
Abacionidae), has been described (Shelley et al. 2003a) and several new species
in the order Chordeumatida await description. Additionally, the ranges of a
half-dozen or so species have been dramatically extended. Papers have been
published on Pleuroloma flavipes and the tribe Pachydesmini (Polydesmida:
Xystodesmidae) (Shelley et al. 2003b, Shelley & McAllister 2006),
Scytonotus granulatus (Polydesmida: Polydesmidae) (Shelley et al.
2005), Virgoiulus minutus (Julida: Blaniulidae) (McAllister et al.
2005), and Auturus l. louisianus (Polydesmida: Euryuridae) (McAllister
et al. 2006). This research will continue and expand into the Plains proper
from Kansas northward.
fauna of Alaska and northern British Columbia (BC), Canada.
Before 2006, Alaska (AK)
was the only significant part of NA that had never been investigated by a
knowledgeable diplopodologist. Only 20 or so samples existed from the state, all
collected incidentally by non-specialists researching other organisms, and most
were from the southern extremity of the Panhandle. Coastal forested environments
from Anchorage/Kenai Peninsula to the southern Panhandle are comparatively warm
& moist and likely harbor diverse faunas, particularly the true rainforests that
harbor a wealth of species from coastal British Columbia to Oregon. Alaska
is also biogeographically significant because of its role in faunal exchange
between NA & Asia through the former Bering Land Bridge, and 7 millipede
families in BC and the northwestern states demonstrate "trans-Beringian
connections" and also occur in east Asia (Russia, Japan, Korea, Manchuria).
Phylogenetically significant forms, anatomical "missing links," conceivably
await discovery in suitable Alaskan habitats, which may also harbor undiscovered
forms of endemic Asian taxa that have not dispersed farther south and hence are
unknown from NA. Through generous support from the National Geographic Society,
I spent 6 weeks in Alaska in summer 2006 searching for and collecting millipedes
and was accompanied on part of this expedition by M. Medrano, University of New
Mexico. One new species was discovered along with astonishing range extensions
of families known previously from southwestern BC and the northwestern US, and
two publications are in press (Shear & Shelley in press, Shelley et al.
in press). If funding is obtained, a second expedition will be conducted in
2007 that will extend into northern coastal BC, primarily to try to confirm the
exciting discovery of the tropical order Glomeridesmida on an island near Prince
Rupert (Shelley et al., in press) Further discoveries of high
biogeographical and phylogenetic significance are plausible in this, the
northwesternmost corner of North America, and will be announced on this website.
Filka, M. E., & R. M. Shelley. 1980. The
milliped fauna of the Kings Mountain region of North Carolina (Arthropoda:
Diplopoda). Brimleyana, 4:1-42.
McAllister, C.T., & R.M. Shelley. 2005.
Discovery of the milliped, Auturus louisianus louisianus (Chamberlin,
1918), in Texas (Polydesmida: Euryuridae). Ent. News, 116(3):187-188.
____, ____, H. Enghoff, & Z. D. Ramsey. 2005.
Distribution of the milliped Virgoiulus minutus (Brandt, 1841) (Julida:
Blaniulidae). Western North American Nat., 65(2):258-266.
Shear, W.A., & R.M. Shelley. 2007. Tingupa
tlingitorum, n. sp., a new milliped species from Haines, Alaska, USA, with
notes on the generic distribution and a revised key to species (Chordeumatida:
Tingupidae). Zootaxa, in press.
____, ____, & H. Heatwole. 2003. Occurrence
of the milliped Sinocallipus simplipodicus Zhang, 1993 in Laos, with
reviews of the Southeast Asian and global callipodidan faunas, and remarks on
the phylogenetic position of the order (Callipodida: Sinocallipodidea:
Sinocallipodidae). Zootaxa, 365:1-20.
Shelley, R. M. 1978a. Millipeds of the
eastern Piedmont region of North Carolina, U.S.A. (Diplopoda). J. Nat. Hist.,
_____. 1978b. Diplopoda, pp. 222-223, In:
Zingmark, R. G., ed., An Annotated Checklist of the Biota of the Coastal Zone
of South Carolina. Univ. of South Carolina Press, 364 pp.
_____. 1988. The millipeds of eastern Canada
(Arthropoda: Diplopoda). Can. J. Zool., 66:1638-1663.
_____. 1990a (1989). Revision of the milliped
family Eurymerodesmidae (Polydesmida: Chelodesmidea). Mem. American Entomol.
Soc. No. 37:1-112.
_____. 1990b. A new milliped of the genus
Metaxycheir from the Pacific Coast of Canada (Polydesmida: Xystodesmidae),
with remarks on the tribe Chonaphini and the western Canadian and Alaskan
diplopod fauna. Can. J. Zool., 68:2310-2322.
_____. 1994. The milliped family
Nearctodesmidae in northwestern North America, with accounts of Sakophallus
and S. simplex Chamberlin (Polydesmida). Can. J. Zool.,
_____. 1998a. Occurrence of the milliped
Glyphiulus granulatus (Gervais) in the Hawaiian Islands (Spirostreptida:
Cambalidea: Cambalopsidae). Bishop Mus. Occ. Paps. No. 56:36-37.
_____. 1998b. Interception of the milliped
Rhinotus purpureus (Pocock) at Quarantine, and potential introduction of the
order and family into the Hawaiian Islands (Polyzoniida: Siphonotidae).
Bishop Mus. Occ. Paps. No. 56:54-55.
_____. 1998c. Occurrence of the milliped
Trigoniulus corallinus (Gervais) on O’ahu and Kaua’i (Spirobolida:
Pachybolidae: Trigoniulinae). Bishop Mus. Occ. Paps. No. 56:55-57.
_____. 1998d. Introduced millipeds of the
family Paradoxosomatidae on Pacific Islands (Diplopoda: Polydesmida).
Arthropoda Selecta, 7(2):81-94.
_____. 1999. Centipedes and Millipedes, with
emphasis on North American fauna. Kansas School Nat., 45(3):1-15.
_____. 2000a. Annotated checklist of the
millipeds of North Carolina (Arthropoda: Diplopoda), with remarks on the genus
Sigmoria Chamberlin (Polydesmida: Xystodesmidae). J. Elisha Mitchell
Sci. Soc., 116(3):177-205.
_____. 2000b. Parajulid studies II. The
subgenus Hakiulus Chamberlin (Julida: Parajulidae: Parajulinae: Aniulini).
_____. 2000c. Parajulid studies III. The
genus Gyniulus Loomis (Parajulinae: Aniulini). Myriapodologica,
_____. 2001a (2000). Annotated checklist of
the millipeds of Florida (Arthropoda: Diplopoda). Insecta Mundi,
_____. 2001b. A synopsis of the milliped
genus Aniulus Chamberlin (Julida: Parajulidae: Parajulinae: Aniulini).
Texas Mem. Mus. Speleol. Monogs., 5:73-94.
_____. 2002a. The millipeds of central Canada
(Arthropoda: Diplopoda), with reviews of the Canadian fauna and diplopod
faunistic studies. Can. J. Zool., 80:1863-1875.
_____. 2002b. Annotated checklist of the
millipeds of California (Arthropoda: Diplopoda). Western North American Nat.
_____. 2002c. The milliped genus Oriulus
Chamberlin (Julida: Parajulidae). Can. J. Zool., 80:100-109.
_____. 2003 (2002). A revised, annotated,
family-level classification of the Diplopoda. Arthropoda Selecta,
_____. 2003. A new polydesmid milliped genus
and two new species from Oregon and Washington, USA, with a review of
Bidentogon Buckett and Gardner, 1968, and a summary of the family in western
North America (Polydesmida: Polydesmidae). Zootaxa, 296:1-12.
_____. 2003. Redescription of the milliped
Amphelictogon subterraneus bahamiensis Chamberlin, 1918, with an assessment
of the family Chelodesmidae in the Bahamas (Polydesmida: Leptodesmidea). Zootaxa,
_____. 2004a (2002). Parajulid studies V. The
genera Pseudojulus Bollman and Arvechambus Causey (Parajulinae:
Aniulini). Insecta Mundi, 16(4):191-204.
_____. 2004b. The milliped family
Pyrgodesmidae in the continental United States, with the first record of
Poratia digitata (Porat) from the Bahamas (Polydesmida). J. Nat.
_____. in submission. Arvechamboides
ocala, n. gen., n. sp., a new aniulinine milliped from peninsular Florida,
USA (Julida: Parajulidae). submitted to Zootaxa.
_____, & D. R. Whitehead. 1986. A
reconsideration of the milliped genus Sigmoria, with a revision of
Deltotaria and an analysis of the genera in the tribe Apheloriini (Polydesmida:
Xystodesmidae). Mem. American Entomol. Soc. No. 35:1-223.
_____, & S. F. Swift. 1998. The milliped
order Julida in the Hawaiian Islands. Bishop Mus. Occ. Paps. No.
_____, & P. T. Lehtinen. 1999. Diagnoses,
synonymies, and occurrences of the pantropical millipeds, Leptogoniulus
sorornus (Butler) and Trigoniulus corallinus (Gervais) (Spirobolida:
Pachybolidae: Trigoniulinae). J. Nat. Hist., 33:1379-1401.
_____, & S. I. Golovatch. 2000. The milliped
family Haplodesmidae in the Hawaiian Islands, with records of Prosopodesmus
jacobsoni from Florida and Louisiana (Diplopoda: Polydesmida). Bishop
Mus. Occ. Paps., 64:48-49.
_____, & R. L. Hoffman. 2004. A
contribution on the South African milliped genus Nematozonium Verhoeff,
1939 (Siphonophorida: Siphonorhinidae). African Ent., 12(2):217-222.
_____, & C. T. McAllister. 2006.
Composition and distribution of the milliped tribe Pachydesmini west of the
Mississippi River (Polydesmida: Xystodesmidae). Western North American
_____, & M.F. Medrano. 2006. Nesoressa
crawfordi, n. gen., n. sp., a montane island milliped in New Mexico, USA;
proposal of the new tribe Nesoressini and a preliminary cladogram of the lineage
"Aniulina" (Julida: Parajulidae). Zootaxa, 1285:31-50.
____, & W.A. Shear. 2006. Leonardesmus
injucundus, n. gen., n. sp., an aromatic, small-bodied milliped from
Washington State, USA, and a revised account of the family Nearctodesmi-dae (Polydesmida).
Zootaxa, in press.
____, & C.T. McAllister. 2006. Distribution
of the milliped genus Apheloria virginiensis (Drury, 1770) west of the
Mississippi River; First record of A. v. reducta Chamberlin, 1939, from
Kansas (Polydesmida: Xystodesmidae).
_____, S. B. Bauer, & S. F. Swift. 1998. The
milliped family Paradoxosomatidae in the Hawaiian Islands (Diplopoda:
Polydesmida). Bishop Mus. Occ. Paps. No. 56:43-53.
_____, P. Sierwald, S. B. Kiser, & S. I.
Golovatch. 2000. Nomenclator generum et familiarum Diplopodorum II. A List of
the Genus and Family-Group Names in the Class Diplopoda from 1958 through 1999.
Pensoft Publishers, Sofia, Bulgaria, 167 pp.
_____, & G. B. Edwards. 2002. Introduction of
the milliped family Rhinocricidae in Florida (Spirobolida). Ent. News,
_____, C. T. McAllister, & J. L. Hollis.
2003a. A new milliped of the genus Abacion Rafinesque, 1820 from
Arkansas, U. S. A. (Callipodida: Abacionidae). Zootaxa, 170:1-7.
____, ____, & S. B. Smith. 2003b. Discovery
of the milliped Pleuroloma flavipes (Polydesmida: Xystodes-midae) in
Texas, and other records from west of the Mississippi River. Ent. News,
____, ____, & Z. D. Ramsey. 2005a. Discovery
of the milliped, Scytonotus granulatus (Say, 1821) in Okla-homa, with a
new record from Alabama and a review of its distribution (Polydesmida:
Polydesmi-dae). Western North American Nat., 65(1):112-117.
____, ____, & T. Tanabe. 2005b. A synopsis of
the milliped genus Brachycybe Wood, 1864 (Platydesmida: Andrognathidae).
Fragmenta Faunistica, 48(2):137-166.
____, ____, & M.F. Medrano. 2006.
Distribution of the milliped genus Narceus Rafinesque, 1820 (Spirobolida:
Spirobolidae): Occurrences in New England and west of the Mississippi River, and
a summary of peripheral localities; first records from Connecticut, Delaware,
Maine, and Minnesota. Western North American Nat., 66(3):374-389.
____, R. Carmany, & J. Burgess. 2006.
Introduction of the milliped, Trigoniulus corallinus (Gervais), in
Florida (Spirobolida: Trigoniulidae). Ent. News, 117(2):239-241.
____, R.A. Cannings, P.T. LePage, & K.J.
White. 2006. A glomeridesmid milliped in Canada (Diplopoda: Glomeridesmida).
Ent. News, in press.
____, W.A. Shear, W.P. Leonard, & K. Ovaska.
2007. Opiona columbiana Chamberlin, 1951: Distribution extensions into
the Alexander Archipelago, Alaska, and eastern & southern Washington State, USA;
new records from Vancouver Island, British Columbia. Check List, in
Sierwald, P., W. A. Shear,
R. M. Shelley, & J. E. Bond. 2003. Millipede phylogeny revisited in the light of
the enigmatic order
Siphoniulida. J. Zool. Syst. Evol. Res., 41:87-99.