MYRIAPODA

bubblesvoltaireInternet and Web Development

Nov 10, 2013 (4 years and 1 month ago)

113 views


1

MYRIAPODA


Henrik Enghoff

Natural History Museum of Denmark (Zoological Museum)


2005


<
page and fig. references, “RFB”
,

refer to

Ruppert, Fox & Barnes: Invertebrate Zoology, 7th. ed. 2004.>


There are four classes of Myriapoda, viz. Chilopoda (centipedes
,
DA:

S
KOLOPENDRE
),
Diplopoda (millipedes,
DA:

T
USINDBEN
), Pauropoda (pauropods,
DA:

P
AUROPODER
) and
Symphyla (symphylids,
DA:

S
YMFYLER
).





THE POSSIBLE MONOPHYLY OF MYRIAPODA AND THE RELATIONSHIPS
BETWEEN THE MYRIAPOD CLASSES


(Also read “Phylogeny of
Tracheata” in RFB p. 718
-
720”)


Myriapod phylogeny is unsettled, but possibly the four myriapod classes plus the class
Hexapoda constitute a monophyletic 'subphylum' Uniramia, also known as Atelocerata
and Tracheata.


The presence of numerous legs, which h
as given the myriapods their name, is obviously a
symplesiomorphy. Within the framework of a monophyletic Uniramia, several sister
-
group relationships have been proposed:




(Hexapoda)


(Myriapoda)



(Hexapoda)


(Symphyla)



(Hexapoda)


(Chilopoda)



(Chilopoda
)
-

((Hexapoda)


(Symphyla+Pauropoda+Diplopoda))


The following traits have been mentioned as possible synapomorphies for the four
myriapod classes, i.e., as arguments for a monophyletic group Myriapoda

(numbering
continued from first part of compendium)
:


1.

N
o mandibular abductor muscle; abduction o
f mandibles effectuated indire
ctly by
the movable anterior tentorium

(Fig. 1)

2.

M
edian eyes never present (in Crustacea, the median eyes are represented by the
naupli
us eye
,

in Hexapoda, they are represented by
the

ocelli
.


2

3.

No perforat
orium in the spermatozoa (Fig.2
:

"1
-
laget acrosom" (one
-
layered
acrosome), in contrast to the two
-
layered acrosome in "Insecta" which is
considered to be the original state)


All these have been considered reductional characters and th
erefore of limited value. The
absence of an abductor muscle may, however, be primary, i.e., a plesiomorphy, and the
same may be tru
e of the mova
bility of the tentorium (Klass & Kristensen i Deuve ed.,
2000). The presence
of the anterior tentorium in it
self

appears as an apomorphy
immediately below the myriapod level, i.e. as an apomorphy for Uniramia
.


The characters invoke
d

in favour of the hypothesis of a sister
-
group relationship between
Symphyla and Hexapoda are possibly symplesiomorphies or convergenci
es:


4.

T
hree pairs of buccal appendages

(mouthparts)

(
RFB:

fig. 20
-
7
B
-
C
, p.
7
10)
.
Ruppert & Barnes follow

Manton in rejecting this similarity based on
differences

between the buccal appendages of symphylids and hexapods: this suggests that
the presence of th
ree pair of buccal appendages could be convergent.

5.

S
econd pair of maxillae forming a labium (‘lower lip’). This character, too, may
be regarded as a convergence. The morphological interpret
ation of the ‘lower lip’
in Dip
lopoda and Pauropoda is still under
debate (cf. below).


The basis of the hypothesis of a sister
-
group relationship between Chilopoda and
Hexapoda is
tenuous:


6.

In both groups the gonopores are

located

at the posterior end of the body, unlike
the situation in Diplopoda, Pauropoda and Symphyla

(‘Progoneata’, cf. below)
where they are placed near the anterior end. Out
-
group comparison (with
Crustacea and Chelicerata) is of no help here, but the posterior gonopore is most
likely the original condition within Uniramia and thus cannot be used as an

argument in favour of a Chilopoda
-
Hexapoda
sister
-
group

relationship.


There are several similarities between Hexapoda on the one hand, and Diplopoda+

Pauropoda+Symphyla on the other. They are all quite subtle, and none is persua
sive
ly
synapomorphic.
One
example

is:


7.


The eversible coxal sacs which are found in Symphyla (
RFB:

p.

711
), certain
Diplopoda (Penicillata, Colobognatha, Nematophora) and certain (‘primitive’
)
Hexapoda. The coxal sacs are probably symplesiomorphic and have become lost
in Chilopoda,

Pauropoda, many Diplopoda and most Hexapoda).


Wheeler et al. (1993) analysed arthropod relationships using one morphological and two
molecular (DNA) data sets. Their analysis included Diplopoda and Chilopoda (but not
Symphyla and Pauropoda) as well as nu
merous groups of Hexapoda, Crustacea and
Chelicerata. Both molecular data seta indicated that Diplopoda and Chilopoda were more
closely related to each than to any other the other included groups and thus support the
hypothesis of myriapod monophyly.

(The
analysis of the morphological character set


a

3

character set with several flaws


did not resolve the relationship between Diplopoda,
Chilopoda and Hexapoda.)


It was suggested above that Chilopoda differ from the other myriapod classes. The latter,
viz.,

Diplopoda, Pauropoda and Symphyla, together constitute the group Progoneata. This
name (‘pro’: in front, ‘gon
-
’: having to do with sexual organs) refer to a possible
synapomorphy between the three classes, viz.:


8.

The gonopore is placed anteriorly on the b
ody (cf. the discussion under chara
c
ter
6
).


Other possible synapomorphies between the three classes

(i.e., autapomorphies for
Progoneata) are:


9.

clypeus and labrum are fused (in Chilopoda and Hexapoda
the
labrum is separated
from
the

clypeus by a suture a
nd is ± movabl
e. RFB: fig. 20
-
2C, p.
705
, shows
the
clypeus in a chilopod;
the
labrum is not visible, but is placed in ’the black hole’
be
tween clypeus and first maxilla
.

10.

T
he body segments have ventral apodemes
(Fig. 3
).
In Diplopoda and

Pauropoda
these
are the tracheal apodemes (see below). In
Symphyla
there are no tracheae
connected with the apodemes


the tracheae may be secondarily reduced like in
most Pauropoda.

11.

T
richobothria basally swollen. Trichobothria

are a special type of sensory hair
s

which ar
e set in a complicated socket. Trichobothria

occur in numerous groups

of
terrestrial arthropods (
especially in arachnids, but
unfo
rtunately not in Chilopoda),
but

in Progoneata the trichobothria are characterised by having the base of the hair
swollen
(Fig
. 4
).
In

Symphyla
there is one such pair of trichobothria in the poste
rior
end of the body (
RFB:

fig. 20
-
7D, p. 7
10).
In

Pauropoda
there are five pairs
laterally on the body
(
RFB:

fig.
20
-
13, p. 718
).
In

Diplopoda t
richobothria are
known only from the Peni
cillata

where there are 3 pairs on each side of the head. In
spite of the different body parts where the trichobothria are situated, the
characteristic structure of the p
r
ogoneate trichobothria be regarded as apomorphic.


Within Progoneata, Symphyla are si
ster
-
group to Diplopoda + Pauropoda. Synapomorphies
between Diplopoda and Pauropoda include:


12.

Immediately behind t
he mandibles there is a complex ‘lower lip’

(Fig. 5
), the
composition of which is con
troversial. Some regard it as a

composite of the two
pair
s of maxillae, others maintain that it is formed exclusively by the first pair of
maxillae, the second pair being entirely suppressed; at least

part of the dorsal part of
the second maxillary segment is represented by the ‘collum’ (R
F
B
:

fig.
20
-
9, p. 712
,
fig.
20
-
13, p. 718
). Cf
.

character 5

above.

13.

In both groups, the spiracles are situated on the sterna, near the leg bases (
RFB:

fig.
20
-
10B, p. 713
). Both groups have
tracheal apodemes

associated with

the spiracles
(cf. character 10
). Tracheae have arisen
several times independently in arthropods.
The ventral system in

Diplopoda + Pauropoda undoubt
edly represents one
‘invention’ of tracheae, whereas it is more doubtful if the lateral system in non
-

4

scutigeromorph centipedes (
RFB:

fig. 20
-
2E, p. 705
) is homol
ogous with that of
Diplopoda + Pauropoda. The tracheal system in Symphyla (
RFB:

fig.
20
-
7, p. 7
10)
is even more dubious in this respect. The dorsal tracheal system of scutigeromorph
centipedes (
RFB:

fig. 20
-
2B, p. 705
) certainly rep
re
sents an independent ‘
invention’.


Based on the characters discussed above, the relationships of the myriapods can be
illustr
ated as in the cladogram, Fig. 6
.


Alternative relationships between the myriapod classes have been suggested. Fig.
2

thus
suggests a sister
-
group relati
onship

between Pauropoda and Chilopoda
,
based
exclusively
on
the
morphology of spermatozoa; this similarity is probably a symplesiomorphy.
Symphyla + Chilopoda have also been regarded as sister
-
groups, mainly because both
classes lack limbs on the last two

body segments. Balanced against the autapomorphies for
Progoneata suggested above
,

this character is, however, not convincing.



5

CLASS CHILOPODA


CENTIPEDES

(DA.: SKOLOPENDRE)


RFB:

703
-
710
.


The numbers of apomorphies

in this section refer to Fig. 7
.


C
hilopoda autapomorphies:


1.

F
irst pair of body limbs transformed into poisons fangs (‘forcipules) (
RFB:

fig. 20
-
2, A, C, p. 705
).

2.

S
econd maxilla in the embryo provided with an ‘egg
-
tooth’.

3.

Nucle
us of spermatozoon spiral
-
shaped


System
atic review of Chilopoda



centipedes


More than 3000 species of centipedes have been described. Thirty
-
two species have been
recorded in Denmark.



Order Scutigerom
orpha


Ca. 130 species from the warmer parts of all continents. Easy to recognize by the 15 pairs
of extremely long
, multi
-
segmented l
egs, and equally extremely long

antennae. Composite
eyes which may be inherited from the common ancestor of all centipedes although some
structural details suggest that the eyes of scutigeromorphs

may be derived from single eyes
of the t
ype
found in Lithobiomorpha and Sco
lopendromorpha; in the latter case the
secondarily composite eye in Scutigeromorpha is an autapomorphy.
Certain
autapomorphies include:


16.

T
he dorsal spiracles (
RFB:

fig. 20
-
2B, p.705
)

17.

T
he strongly sub
-
segmented tarsi


Scut
igera coleoptrata

is common in southern Europe and has been found occasionally in
houses in Denmark (introduced).



Order Lithobiomorpha


Ca. 1500 species from all parts of the World. Fifteen pairs of walking legs like in
Scut
igeromorpha, but the tarsi

are

not multi
-
segmented, and the eyes are not composite; the
spirac
les are lateral and

are present only on
some

of the segments. An autapomorphy is:


18.

T
he single testicle (
RFB:

fig. 20
-
4, p. 707
). Two testicles are formed in the embryo,
but one is later reduce
d. (Scutigeromorpha have paired testicles; see below on
Scolopendromorpha and Geophilomorpha, character 12).


A further, possible autapomorphy is:


6


19.

coxal pores (Fi
g. 8,
cf. also below) on at least two pairs of legs, not only on the last
pair as in Scolopen
dromorpha and Geophilomorpha.


Lithobius forficatus

(to 3 cm long) is extremely common in Denmark, like several smaller
species of the same genus.
Lamyctes em
a
rginatus

is the only myriapod known from
Greenland; it is parthenogenetic and is also known from
Denmark.



Order Craterostigmomorpha


Only one species,
Craterostigmus tasmanianus
, from Tasmania and New Zealand. Hatches
from the egg with 12 pairs of legs, the adult number of 15 pairs is reached after one moult
;
the number of leg
-
pairs is certainly a s
ymplesiomorpy with the two orders above.
C.
tasmanianus

superficially resembles a
Lithobious
.



Order Scolopendromorpha


Ca. 500 sp
ecies in all parts of the World
, mainly in warm regions. They resemble
Lithobiomorpha superficially, but they have 21 or
23 p
airs of walking legs. An
aut
apomorphy is:


20.

The te
rgum of the poison fang segment

is fused with that of the following segments
(that carrying the first pair of
walking legs). (The fused tergum

is seen in
RFB:

fig.
20
-
1A, p. 704

as a trapezoid plate just beh
ind the head).


Family Scolopendridae: four eyes on each side of the head. The very large centipedes
belong here, genus
Scolopendra

and others in the tropics and subtropica including southern
Europe.


Fam. Cryptopsidae: no eyes.
Cryptops hortensis

(2
-
3 cm)

in Denmark.
Scolopocryptops (=
Otocryptops).



Order Geophilomorpha


Da: jordskolopendre


Ca. 1000 speices in all parts of the World. From 29 to almost 200 pairs of legs. No eyes.
Good autapomorphies include:


21.

the earthworm
-
like burrowing technique (
RFB:

707
)

22.

the constant number of
14
antennal articles. In the other orders, the number is large and
variable.


The high number of legs and the lack of eyes are other possible autapomorphies.



7

Several families, a dozen species in Denmark including
Geophilus car
pophagus,

which is
bioluminescent (glows in the dark) and occurs in old houses, and
Strigamia maritim
a
,
which is sometimes abundant under seaweed on the beach.



Centipede phylogeny


The phylogeny of centipedes has been subject of much debate. The discussi
on illustrates
very well the difficulties with deciding which characters are original, plesiomorphic, and
which are derived, apomorphic. The Geophilomorpha have been regarded as sister
-
group to
the ot
her centipede orders, and so have the

Scutigeromorpha. T
he class has also been
divided into two groups:
Anamorpha (= Scutigeromorpha + Lithobiomorpha) and
Epimorpha (= Scolopendromorpha + Geophilomor
pha). Based, among other things, on
increased knowledge of the fifth order, Craterostigmomorpha, Dohle (1985) a
nd Shear &
Bonamo (1988) were able to present a convincing phylogenetic analysis, according to which
rela
tionships are as shown in Fig. 7
.


The group Anamorpha was named after the mode of postembryonic development in its
members, viz.,
hemianamorphosis
: Th
e juveniles hatche
d from the egg have 4 pairs of
l
e
gs
(excluding the poison fangs) in Scutigeromorpha, 6
-
7 pairs in Lithobiomorpha
. The adult
number (15 pairs) is gradually attai
ned during growth, and when it
h
a
s been reached, no
new leg
-
pairs are added du
ring succeeding moults. Hemianamorphosis occurs in all
Pauropoda and Symphyla and also in primitive Diplopoda; this character is thus a clear
symplesiomorphy for the members of ‘Anamorpha’.


Several synapomorphies are shared by
Lithobiomorpha, Craterostigm
omorpha,
Scolopendromorpha and Geophilomorpha, including:


4.

the head is flattened

5.

the tentorium is reduced in a characteristic way

6.

the sternum and coxae of the poison fangs are fused to a coxosternum (
RFB:

fig.
20
-
2, p. 705
, “coxosternite plate

of forcipu
le
”). This is clearly apomorphic, since

the

poison fangs are d
erived from normal walking legs

7.

the last leg
-
pair at least has coxal organs of a characteristic structure. They open to
the surf
ace through coxal pores (Fig. 8
) and probably se
rve a water
-
regula
tory
function

8.

the spermatophore is placed on a web produced by a spinneret in the
rear end of the
male (
RFB:

fig.

20
-
6A

p.
709).



Craterostigmomorpha, Scolopendromorpha og Geophilomorpha share further
synapomorphies:


9.

eggs and young juveniles are protecte
d by parents (
RFB:

fig.
20
-
6C, p. 709
)

10.

juveniles hatch with the full (or almost full) adult number of
segments and
legs.


Scolopendromorpha og Geophilomorpha finally share the following synapomorphies:


8


11.

juveniles hatch with full number of adult number of s
egments and legs

12.

the testicles are fusiform, with vasa efferentia ori
ginating from both ends (Fig. 9
, cf.
RFB:

fig. 20
-
4, p. 707
)

13.

trac
heae from different segments ana
stomose

14.

there is
no median suture on
the
coxosternum (cf. character 6)

15.

there is a
direct a
rticulation between first and fourth article of the poison fang’s
telopodite (Fig.

10
, cf.
RFB:

fig. 20
-
2C, p. 705
).


One character is in strong con
flict with the cladogram, Fig. 7
, viz., the
heterotergy
.

In
Geophilomorpha all terga are of similar size (h
omotergy). In the other orders there is a more
or less pronounced

alteration

between short and long terga: heterotergy. In
RFB:

fig.
20
-
1, p.
704
, the heterotergy is clearly seen in
Lithobius
, not so clearly in
Otocryptops
. In
Scutigera

the short terga are

entirely hidden under the long ones. Intuitively one would believe
homotergy to be original, heterotergy thus being a synapomorphy for all centipedes except
Geophilomorpha. Balanced against characters 4
-
15 above
,

the heterotergy, however, must
be regarded

as convergent or plesiomorphic, in the latter case the homotergy in
Geophilomorpha would be secondary.


Spermatological evidence (Jamieson 1987) is also partly in contrast with the phylogeny
advocated above. Spermatol
og
y does support the sister
-
group rela
tionship between
Scutig
eromorpha and the rest, but

also provide
s

a possible (but not very well founded)
synapomorphy between Lithobiomorpha and Geophilomorpha, which is in conflict with
characters 11
-
15 above.




9

CLASS SYMPHYLA


SYMPHYLIDS, DA
.
: SYMFYLER


RFB:

710
-
711
.


The large spinnerets in the posterior end may constitute an autapomorphy for symphylids. It
is, however, uncertain,

whether the spinnerets are homologous with the cerci of Hexapoda
(the cerci of some Diplura have spinning glands like the s
pinnerets of Symphyla). The
position

of the two trichobothria is another possible autapomorphy (but not the trichobothria
by them
selves, see character 18 in the chapter "The possible monophyly of Myriapoda and
the relationships between the myriapod classes
"
). Also, the extra tergites may constitute a
symphylidan autapomorphy although their number is variable.


The
styli

mentioned by RFB (p. 711) (Fig.
11
) also occur in some apterygote hexapods:
Archaeognatha and Diplura. Also, stylus
-
like structures are fou
nd in the diplopod subclass
Penicillata, and in Pauropoda.


About 160 species of Symphyla have been described
.
Four species have been found in
Denmark.
Scutigerella immaculat
a



one of the largest symphylids


is very common in
humid forest soil and simila
r places in Denmark.




10

CLASS DIPLOPODA


MILLIPEDES, DA.: TUSINDBEN


RFB:

711
-
717.


The number
s

of apomorphies
in this chapter refer to Fig. 12
.


Good autapomorphies for millipedes are:


4.

diplosegments (
RFB:

713).

5.

spermatozoa without
a flagellum (Fig. 2
)

6.

a
ntennae with 8 a
rticles, with four large, cone
-
shaped sense organs on the tip (Fig.
13)


There are 16

orders of millipedes in the current classification, a clear example of
‘taxonomic inflation’. Looking at the degree of
distinctiveness and
recognisability

it is
rather the
superorders

of millipedes that may be compared with insect of arachnid orders.


About 10,000 species of millipedes have been described; 42 species are known from
Denmark.



SUBCLASS PENICILLATA


pincushion millipedes, da.: penseltusindbe
n


easily recognized by the autapomorphic character:


12.

tufts of bristles along the sides of the body and in the posterior end


About 100 described species from all regions. On
ly a few mm long,

the pincushion
millipedes exhibit many primitive traits and seem

not to have departed very much from the
millipede ground
-
plan. They thus have retained

trichobothria (cf. character 18

in the section
on myriapod relationships), their cut
icle is not calcified, and the
number of legs is relatively
low: 11
-
17 pairs in adul
ts. Terga, pleura and sterna are independent (except that the terga
are fused in
to

twos [
d
iplosegments]). No legs are modified for copulation. Sperm transfer
happens indirectly: the male deposit spermatophores which are later taken in by the female
(
RFB:

f
ig. 20
-
12E, p. 717
)
.


It has recently been suggested
(Kraus & Brauckmann 2003)
that the Penicillata are closely
related to the ex
tinct Arthropleurida, giant (more than 1
m
, perhaps even more than 2m
)

myriapods from the Devonian,

Carboniferous
and Permian
pe
riods.


One
order, Polyxenida. One species
in Denmark,
Polyxenus lagurus
. See
RFB:

fig. 20
-
8B,
p. 712
.
P. lagurus

is often, but not always parthenogenetic, and it is this species which R
FB
(p. 717
) refers to.






11

SUBCLASS CHILOGNATHA


Superorder Pentazoni
a


Good autapomorphies:


13.

the last pair of legs (and sometimes also the penultimate and
ante
penultimate pairs)
of the male are modified into clasping organs which hold the female during
copulation

14.

the sterna are divided in the midline


Pentazonia are also c
haracterized by a relatively low number of legs: 17
-
37 pairs in adults.
Terga, pleura and sterna are independent. The group includes 3 orders and a total of ca.
350 described species from all parts of the World. One species in Denmark.


Order Glomeridesmi
da
. Unlike other Pentazonia, glomeridesmidans cannot roll up into a
sphere. A few cm long. Occur in South and Central America
, and in SE Asia.


Order Sphaerotheriida
. Giant pill millipedes (da.: kæmpekugletusindben). Up to the size
of a golf ball when rol
led

u
p. Occur on the southern hemisphere except South America.


Order Glomerida
.
Pill millipedes (da.: kugletusindben). Rarely more than 7 mm in
diameter when rol
le
d

up
. Occur
on the northern hemisphere and S
E Asia. One species,
Glomeris marginata
, in Denm
ark (shown in
RFB:

fig.
20
-
8D, E, p. 712
), common in
deciduous forest.


Superorder Colobognatha


Good autapomorphies:


15.

mouthparts more or less modified into stiletto
-
like structures with unknown
function

16.

first juvenile stadium hatching from the egg with fo
ur pairs of legs (three pairs in
other millipedes, see
RFB:

fig. 20
-
12F, p. 717
)

17.

a parent (the mother in some species, the father in others) protect
s

the eggs by
rolling itself around them like in some centipedes (character 9 in the section on
centipedes).


The group includes four orders and a total of ca. 300 species, a few cm long, described
from all parts of the World.


Order Platydesmida.

Mouthparts only moderately modified. Occur on the northern
hemisphere and SE Asia.


Order

Polyzoniida
. Mouthparts st
rongly modified. Eyes present. Occur in all parts of the
World.
Polyzonium germanicum

(Fig. 14
) occurs in Denmark, but is rare.



12

Order Siphonocryptida
. Very similar to preceding order.
Four
s
pecies f
rom SE Asia, the
Canary Islands and Madeira.


Order Siph
onophorida
.
Mouthparts stiletto
-
like (Fig.14
). No eyes. Occur in North,
Central and South America, South Africa and Southeast Asia. The
ruling
World
Champion in leg numbers belongs here:
Illacme plenipes

from California (up to 750
legs).


Superorder Nemato
phora


The name means ‘thread
-
bearer’, and accordingly a good synapomorphy is:


18.

posterior end with one or m
ore pairs of spinnerets (Fig. 15
)


In Nematophora, the sterna are not fused with the pleura. In this character, Nematophora
resembles the superorders

mentioned above and differs from those treated further down.


The group includes three orders and a total of ca. 1000 described species. Three species
are
known from Demmark.


Order Stemmiulida
. One to two eyes on each side of the head. Body a few cm long
,
circular in transverse section,

tapering posteriorly. No defenc
e glands, but some species
exhibit an incredible defensive behaviour, escaping from aggressors in long jumps. Occur
in South and Central America, tropical Africa and India.


Order Callipodida
. Many eyes. Up to

10 cm long, cylindrical. Defenc
e glands present
(smell horrible!). Occur in the warmer parts of the H
olarctic region includi
ng the
Mediterranean region.


Order Chordeumatida
.
Many eyes (
except in
some species
which are
blind). Body a few

cm long, often moniliform or with flat ‘wings’ like Merocheta (see below). Occur in all
regions. The Danish Nematophora belong here, our commonest species is
Craspedosoma
rawlinsi

which occurs in humid forest soil.


Superorder Merocheta


flat
-
backed mill
ipedes, da.: kiletusindben


Good autapomorphies:


19.

n
umber of segments almost constant:
the vast majority of the

species have 19
-
20
segments
1

in the adult

(other Helminthomor
pha, cf. Fig. 12
, have m
ore segments,
and the number is

often variable within each s
pecies).

20.

no eyes (convergent with many subgroups within other superorders)




1

T
raditionally, segments of millipedes are counted as follows: The four anteriormost segments, which are
not diploseg
ments, are each counted as one. The following segments, which
are

diplosegments, are

also
counted as one each. The telson, which is
not

a segment, is also counted as one. A merochetan millipedes
with ’20 segments’ thus consists of the four anterior, simple segments, 15 diplosegments, and the telson
(4+15+1 = 20).


13

21.

defenc
e glands with two compartments, produce HCN (mentioned by
RFB:

715
),
this type of glands
only

occurs in Merocheta.


In most species of Merocheta the body rings (‘segments’) ha
ve a pair of
keel
-

or

winglike
dorsolateral outgrowths
, giving the dorsal side a flattened appearance. Using the flat
back, the merocheta
ns wedge their way between, e.g.
, fallen leaves on the ground (
RFB:

“flat wedgers, p. 714
).


Only one order:


Order Po
lydesmida
. Ca. 3000 described species, from a
few mm to ca.10 cm long,
occur
r
i
n
g

in
all parts of the World. Ten species in Denmark, including several of the
genus
Polydesmus

(pictured without a name on
RFB:

fig. 20
-
8C, p. 712
).


Superorder Juliformia


cy
lindrical millipedes, da.: cylindertusindben


Good autapomorphies:


22.

the first body segments,
collum
, overlaps the posterior part of the head as well as
the anterior p
art of segment 2 (RFB: fig. 20
-
8F, p. 712
)

23.

Spermatozoa wit
h a “bilayered acrosome” (Fig. 2
). (A “bilayered acrosome” also
occurs in Hexapoda, and loss of one of the ‘layers’, the actin
-
containing
perforatorium, is considered a possible autapomorphy of

Myriapoda [char. 8 in
the chap
ter on myriapod relationships]. In Juliformia, a perforatorium ‘
re
-
appears’, but it lacks actin, is called a pseudoperforatorium and is regarded as a
novelty ‘invented’ by the common ancestor of Juliformia).


Juliformia constitute
the

millipedes as typically understood by laymen: long, cylindrical
animals with plenty o
f legs

(although the highest numbers of legs occur in
colobo
gnathans, cf. above). The defenc
e glands of Juliformia produce benzoquinones


a
type of defensive chemical which is widely distributed among arthropods.


The group

includes three orders with ca.
4000 described species, 27 species in Denmark.
The orders can only be told apart by details in mouthparts and gonopods.


Order Spir
obolida
. From a few t
o more than 20 cm long. Do not
occur naturally in
Europe
, but in all other pa
rts of the World. The genus

Narceus
, mentioned by R
F
B,
belongs here. A small species has been introduced to the greenhouses of the Botanical
Garden in Copenhagen where it seems to thrive.


Order Spirostreptida
. From a few to 30 cm long. Distributed in the same areas as
Spirobolida.
T
he very large
Archispirostreptus gigas

from East Africa, which is one of
the most frequent ‘terrarium millipedes’
, belongs here
. Some species are pests on
peanut
s
, potatoes etc. in Africa.


Order Julida
.
O
ccur naturally on
ly on

the northern hemisphere. Ra
rely longer than 5 cm.
Many common Danish species belong here, including the black
Julus scandinavius
, the

14

brown species of
Cylindroiulus
, and our lar
gest millipede:
Ommatoiulus sabulosus

(up to
5 cm, with two yellow longitudinal stripes). Some species, es
pecially the small, thin
Blaniulus guttulatus
, may be pests on potatoes and sugar beets.


-
o0o
-


The 16
th

millipede order, Siphoniulida, is known only from a handful of specimens. It is
probably related to Colobognatha or Juliformia.



Millipede phylogeny


Enghoff (1984) presented a cladistic analysis of the millipede orders
2
. The results are

shown in the cladogram, Fig. 12

(and in RFB: p. 716)
. Numbering of characters in the

present chapter follows Fig. 12
.


Since 1984, a number of studies on millipede phy
logeny have been published, including
some using molecular characters. So far, however, the results have not stabilized, and the
1984 model is offered here as
,

so far, the most robust one.


The class Diplopoda consists of two subclasses: Penicillata, which

was characterized
above, and Chilognatha (not to be confused with Chilopoda) which is characterized by
the following autapomorphies:


4.

cuticle calcified

5.

most dip
losegments with a pair of defenc
e glands (not more

than one pair
,
although R
F
B 813 suggests the

opposite); the glands are secondarily missing in,
e.g., Chordeumatida.

6.

no trichobothria (cf. character 16
in the chapter on myriapod rela
tionships)

7.

certain muscles and ligaments reduced (in contrast to Penicillata to Penicilalta,
where they have been reta
ined)

8.

spermatozoa ‘depressed’, i.e., strongly shortened along the anterior
-
posterior axis

(Fig. 2
)


Among the five superorders of Chilognatha, four (Colobognatha + Nematophora +
Merocheta + Julifor
mia = Helminthomorpha on Fig. 12
) share an obvious synapomo
rphy,
viz.:


9.

at least one leg
-
pair on segment 7 in the male is modified into gonopods which
serve as copulatory organs.


Nematophora, Merocheta and Jul
iformia (= ‘Eugnatha’ on Fig. 12
) share further
synapomorphies, including:





2

The Siphonocryptida had

not been recognised as a separate order in 1984 but unco
ntroversially belong
in
Colobognatha.


15

10.

terga and pleura fused into p
leuroterga (this
f
u
sion
has, however, happened
convergently in the colobognathan order Platydesmida)


Merocheta and Juliformia are sister
-
groups, united by the apomorphy:


11.

pleuroterga and sterna fused into complete body rings (
RFB:

fig. 20
-
10C, p. 713
).


M
erocheta and Juliformia are sometimes collectively referred to as ‘ring
-
forming
millipedes’.


On Fig. 2
, Pol
yzoniida branch off before Glomerida. This is in con
flict with the
'
strong
'

character 9, and the spermatological evidence on which this part of Fig.

2

is based

is
accordingly dubious.


16

CLASS PAUROPODA


PAUROPODS, DA.: PAUROPODER


RFB: 718.


The branched antennae constitute a good autapomorphy for pauropods. The pauropods
pictured by RFB belongs to the Tetramerocerata and almost has diplosegments like

a
diplopod (6 terga for 9 pairs of legs); in Hexamerocerata the number of terga corresponds to
the number of legs.


About 500 species of Pauropoda have been described, and one or two handfuls of

species
are known from Den
mark.


Order Hexamerocerata
. Many
primitive traits are preserved, including tracheae on the first
body segment and powerful mandibles. Seven species from Africa and South America.


Order Tetramerocerata
. No tracheae, mandibles reduced, weak, number of terga less than
number of leg
-
pairs. I
n all parts of the World.



17

IDENTIFICATION KEY TO MYRIAPODA


Classes/orders o
ccurring in Denmark are shown with CAPITAL LETTERS. Orders not
occurring in Europe are in (brackets).




Key to the myriapod classes


1.

Most body segments with two pairs of legs.

Usually calcified,
slow animals


MILLIPEDES,
DIPLOPODA

-

One pair of legs per segment

2


2.

Usually more than 1 cm long, brownish/yellowish. A pair of
poison fangs behind/below the head


CENTIPEDES, CHILOPODA

-

Smaller than 1 cm, usually whitish. No p
oison fangs

3


3.

Antennae moniliform, unbranched. Twelve pairs of legs

SYMPHYLA

-

Antennae branched. Nine, rarely 10
-
11 pairs of legs

PAUROPODA





Key to the orders of centipedes
, CHILOPODA


1.

15 pairs of legs

2

-

21 or more pairs of legs

4


2.

Ant
ennae and legs extraordinarily long. Big, composite eyes. Spiracles
mid
-
dorsally


Scutigeromorpha

-

Antennae and legs ’normal’. A small group of single eyes on each side
of=瑨e=headI=or=敹敳=miss楮g.=印iracles=later慬
=
=
P
=
=

=
iarge= g污nd=op敮楮gs=on=coxae
=
of= 瑨e=O
J
4=posteriormost= 汥g
J
pairs.=
Body=r敬at楶敬e=compact
=
=
ifqelBflM佒偈m
=
J
=
ko=coxal=por敳=on=posterior=l敧s.=Body=rel慴楶e汹=sl敮der
=
ECraterost楧momorphaF
=
=

=
ONI=rare汹=OP=pairs=of=l敧s
=
pC佌l偅k䑒位佒偈m
=
J
=
O9=or=more=p慩rs=of=l敧s
=
dbl偈fil䵏o偈m
=
=

18



Key to th
e orde
r
s

of millipedes,

DIPLOPODA


(exluding Siphoniulida
)


1.

Characteristic tufts of setae (’brushes’) along the sides of the body. Rarely more
th慮=R=mm=long
=
=
偏i奘bkf䑁
=
J
=
ko=su捨=brushes.=佦t敮=larger
=
O
=
=

=
At=most=NP=s敧m敮瑳=楮c汵d楮g=t
elson.=Body=捡n=be=rolled=楮to=a=sphere
=
P
=
J
=
Adu汴s=wi瑨=more=瑨慮=NT=segm敮瑳=楮捬uding=te汳on.=Body=慬aost=n敶er=capab汥=
of=roll楮g=up=楮to=a=sphere
=
=
4
=
=

=
NP=segm敮ts=楮捬.=t敬son.=Ball=usual汹=>N=捭=in=di慭eter
=
Epphaero瑨eriidaF
=
J
=

J
NO=s敧m敮瑳=楮cl
.=te汳on.=B慬l=Ea汭ost=alw慹sF=<N=捭=in=di慭e瑥r
=
dilMbof䑁==
=
=
=

=

J
OM=s敧m敮瑳=E數ception慬汹=N8=or=up=to=ORF.=ko=敹敳.=啳ra汬l=wi瑨=
dorsolateral=proc敳ses=r敮der楮g=瑨e=dors慬=surfa捥=more=or=less=flat.=Compl整e=
body=rings=E==tergum=H=pl敵ra=H=sternumF
=
=
=
偏i奄bpMf䑁===
=
J
=
Adu汴s=E慬aost=a汷慹sF=w楴i=>=OM=segm敮ts
=
R
=
=

=
Col汵m=cover楮g=瑨e=posterior=part=of=瑨e=head=慮d=瑨e=anterior=part=of=segm敮t=O.=
Body=捩r捵lar=楮=transverse=s散tion.=Compl整e=body=r楮gs=Etergum=H=pl敵ra=H=
sternumF
=
=
=
6
=
J
=
Col汵m=smal
汥rI=慮dLor=body=transverse=sec瑩on=not=cir捵lar.=却ernumI=somet業敳=
ev敮=pl敵raI=indep敮d敮t=sc汥r楴es
=
=
8
=
=

=
eead=w楴h=a=longi瑵d楮a氠su瑵re=start楮g=from=慮terior=marg楮.=䝮慴ho捨ilar極m=
w楴i=a=very=large=m敮瑵m
=
=
EppirobolidaF====
=
J
=
eead=wi瑨out=su捨=
a=suture.=䝮a瑨o捨楬ar極m=d楦fer敮t=
=
T
=
=

=
i慴eral=scler楴es=of=gna瑨o捨il慲ium=Estipi瑥sF=me整=in=midl楮攮=rsua汹=a=f敷=捭=
longI=segm敮ts=of瑥n=h慩ry
=
=
grif䑁==
=
J
=
dn慴ho捨ilar楡l= s瑩pit敳= divid敤= by= m敮瑵m.= rsu慬汹= large= an業慬s= E>= R= 捭F.=
Body=h慩rl敳s
=
=
Eppirostrep瑩daF====
=
=

=
Col汵m= sm慬lI= head= larg敬e= uncovered.= eead⽭ou瑨par瑳= not= att敮uated.= by敳=
usu慬汹=w敬l
J
d敶eloped.=偯ster楯r=end=w楴h=sp楮nere瑳=Em慹=b攠diffi捵lt=to=seeF
=
=
9
=
J
=
Anterior=敮d=d楦fer敮t.=eead⽭ou瑨par瑳=usu慬汹=more=or=汥ss=att敮uat
ed.=At=mos琠
a=few=sing汥=敹esI=of瑥n=no=敹敳=at=慬l.=ko=sp楮nere瑳
=
=

=
=

=
At=most=PO=segm敮ts.=Body=transverse=se捴ion=cir捵lar=or=with=dorsolater慬=
pro橥ctions.
=
=
Ce佒abr䵁qf䑁
=
J
=
Adu汴s=wi瑨=>PO=s敧m敮ts
=

=
=
㄰N
=
rp=to=NM=捭=longI=敹敳=w敬l
J
d敶elopedI=s
trong汹=sculp瑵red=s敧m敮瑳=慮d=oft敮=愠
horrible=sme汬
=
=
Ca汬ipodida
=
J
=
A=f敷=捭=longI=M
J
O=s楮gle=敹es=on=ea捨=side.=te慫汹=s捵lptur敳=s敧m敮瑳I=no=
parti捵lar=smell.=pome=sp散i敳=can=橵mp
=
=
Ept敭m極汩daF====
=
=
ㄱN
=
Body=transverse=section=s敭i捩ccularI=or=dep
r敳sed=s敭i捩r捵污r
=

=
J
=
Body=wi瑨=污rge=or=sma汬er=dorsolater慬=process敳
=

=
=
ㄲN
=
ko=敹敳.=e敡d⽭ou瑨parts=not=att敮uate
=
Edlomeridesm楤aF
=
J
=
A=few=s楮gle=敹敳.=eead⽭ou瑨par瑳=at瑥nu慴e
=

=

19


13.

With a mid
-
dorsal suture

Siphonocryptida

-

No mid
-
dorsal
suture

POLYZONIIDA


14.

Tergum and pleura of each segment fused. Head/mouthparts only slightly
attenuate


Platydesmida

-

Pleura separate from tergum. Head/mouthparts often extremely attenuate

(Siphonophorida)



20

REFERENCES

(
only those cited in t
he compen
dium)


Baccetti, B., Burrini, G., Dallai, R. & Pallini, V. 1979: Recent work in myriapod spermatology (The spermato
-
zoon of Arthropoda XXXI).
-

Side 97
-
111 i Camatini, M. (red.): Myriapod biology.
-

Academic Press London
etc.


Deuve, T (ed.). 2000: Origin
of Hexapods
-

Mémoires du Muséum national d'Histoire Naturelle (under
trykning).


Dohle, W. 1980: Sind die Myriapoden eine monophyletische Gruppe? Eine Diskussion der
Verwandtschaftsbeziehungen der Antennaten.
-

Abhandlungen des naturwissenschaftlichen Ver
eins in
Hamburg (NF) 23: 45
-
104.


Dohle, W. 1985: Phylogenetic pathways in the Chilopoda.
-

Bijdragen tot de Dierkunde 55(l): 55
-
66.


Enghoff, H. 1984: Phylogeny of millipedes
-

a cladistic analysis.
-

Zeitschrift für zoologische Systematik und
Evolution
sforschung 22: 8
-
26.


Jamieson, B.G.M. 1987: The ultrastructure and phylogeny of insect spermatozoa.
-

Cambridge University
Press, Cambridge etc.


Kraus, O. & Brauckmann, C. 2003: Fossil giants and surviving dwarfs. Arthropleurida and Pselaphognatha
(Atelo
cerata, Diplopoda): characters, phylogenetic relationships and construction.


Verhandlungen des
naturwissenshcaftlichen Vereins Hamburg, Neue Folge 40: 5
-
50.


Shear, W.A. & Bonamo, P.M. 1988: Devonobiomorpha, a new order of centipeds (Chilopoda) from the
Middle
Devonian of Gilboa, New York State, USA, and the phylogeny of centiped orders.
-

American Museum
Novitates 2927: 1
-
30.


Wheeler, W.C., Cartwright, P. & Hayashi, C.Y. 1993: Arthropod phylogeny: a combined approach.
-

Cladistics
9: 1
-
39.


21

LEGENDS TO I
LLUSTRATIONS



Fig. 1.

The anterior tentorium is an internal skeletal structure which can be viewed as an
inward extension of the external surface of the head capsule. T
he upper scanning electron
micro
graph shows the the head capsule of a millipede in vent
ral view; the paired tentoria
are aritculated laterally ("tilledningssted"). The lower SEM shows the same he
a
d capsule
in oblique posterior view. The circular hole in the head capsule is the articulation site of
the left antenna. Also

notice the tridentate

labrum w
hich is characteristic of millipedes.



Fig. 2. Spermatozoan structure in myriapods, after Baccetti & al. (1979). Notice that the
branching pattern of the spermatozoan
-
based cladogram differs from the cladogram
recommended in the compendium text (
Figs. 6 and 12).



Fig. 3. Sterna, spiracles and tracheal apodemes in millipedes. The upper SEM shows the
oval sternum in a species of Juliformia. On both sides, sternum is fused with pleura, the
latter hide the tracheal apodemes from view. (In Juliformia
the two sterna of each
diplosegments are fused but the picture only shows the anterior sternum). The lower SEM
shows an isolated sternum of a species of Nematophora. Here the tracheal apodemes are
visible; you can perhaps imagine that they project 'into th
e paper', i.e. into the body.



Fig. 4. Trichobothria in a symphylid (left), a pauropod (center) and a pincushion
millipede (right). Notice the swollen basis of the trichobothria which are located in a
concavity in the cuticle. Of the remaining part of the

trichobothria, only the tips are
shown.



Fig. 5. Gnathochilarium in a pauropod
(left) and a pill millipede (righ
t). Embryos above,
fully developed animals below.



Fig. 6.Suggested relationships within Uniramia (presuming that Uniramia is
monophyletic!)



Fig. 7. Relationships within Chilopoda according to Dohle (1985). Numbers refer to
synapomorphies mentioned in the text.



Fig. 8. Posterior end of a lithobiomorph centipede. Notice the coxal pores.




22

Fig. 9. Male gonads in Chilopoda Epimorpha. Geophilom
orpha left, Scolopendromorpha
right.



Fig. 10. Poison fangs in Geophilomorpha. Notice the undivided coxosternum (cxs) and
the direct articulation between the first and the fourth telopodite article (arrow).



Fig. 11. Leg of a symphylid. Notice stylus (ar
row).



Fig. 12. Relationships within Diplopoda. Modified after Enghoff (1984). Numbers refer
to synapomorphies mentioned in the text.



Fig. 13. SEM of antennal tip of a millipede. Notice the four large sense organs
(autapomorphy for Diplopoda).



Fig. 14
. Millipedes of the superorder Colobognatha. a
-
c:
Polyzonium germanicum
, the
only Danish colobognathan. d: a species of the order Siphonophorida. e: anterior end of
another species of Siphonophorida; notice the extremely pointed head and the stout
antennae
.



Fig. 15. A:
Craspedosoma rawlinsi
, the commonest Danish species of Diplopoda
Nematophora. B: posterior end of a species of Nematophora; notice spinnerets (arrow).



Fig. 16. The fossil millipede group Arthropleurida lived in the Devonian
,

Carboniferous

and Permian
periods. From Kraus & Brauckmann (2003).