The peristomatic structures as a source of systematic characters in the genus Lithobius Leach, 1814 (Myriapoda, Chilopoda)

Abstract

Morphological characters have been widely used in centipede systematics. Here, we aim to obtain morphological information from the preoral chamber and peristomatic structures of lithobiomorph centipedes, with taxonomic sampling focused on the species-rich genus Lithobius Leach, 1814. Towards this goal, we (i) examined the epipharynx and hypopharynx of 32 species belonging to four subgenera of the genus Lithobius , viz. Lithobius Leach, 1814, Monotarsobius Verhoeff, 1905, Sigibius Chamberlin, 1913 and Ezembius Chamberlin, 1919 using light and scanning electron microscopy, (ii) searched for phylogenetically informative characters and (iii) described interspecific variation. Three species of the lithobiid genera Eupolybothrus Verhoeff, 1907, Disphaerobius Attems, 1926 and Neolithobius Stuxberg, 1875 were additionally examined and considered as likely outgroups. New characters and character states are proposed as additions to current phylogenetic datasets. Similarities in the peristomatic structures ally Disphaerobius with Lithobius (Ezembius), suggesting that the subfamily Pterygoterginae is nested within Lithobiinae and Lithobius .

Full text

e peristomatic structures of genus Lithobius 49
The peristomatic structures as a source of systematic
characters in the genus Lithobius Leach, 1814
(Myriapoda, Chilopoda)
Anne-Sarah Ganske1,3, Gregory D. Edgecombe2, Nesrine Akkari1
1 Natural History Museum Vienna, 3rd Zoological Department, Burgring 7, 1010 Vienna, Austria 2 e Na-
tural History Museum, Department of Earth Sciences, Cromwell Road, London SW7 5BD, UK 3 University
of Vienna, Department of Integrative Zoology, Althanstraße 14, 1090 Vienna, Austria
Corresponding author: Nesrine Akkari (nesrine.akkari@nhm-wien.ac.at)
Academic editor: P. Stoev|Received 17 October 2017|Accepted 29 November 2017|Published 7 March 2018
http://zoobank.org/514BFAB6-5BAE-4C73-A98D-18A16B6273BE
Citation: Ganske A-S, Edgecombe GD, Akkari N (2018) e peristomatic structures as a source of systematic
characters in the genus Lithobius Leach, 1814 (Myriapoda, Chilopoda). In: Stoev P, Edgecombe GD (Eds) Proceedings
of the 17th International Congress of Myriapodology, Krabi, ailand. ZooKeys 741: 49–75. https://doi.org/10.3897/
zookeys.741.21706
Abstract
Morphological characters have been widely used in centipede systematics. Here, we aim to obtain mor-
phological information from the preoral chamber and peristomatic structures of lithobiomorph cen-
tipedes, with taxonomic sampling focused on the species-rich genus Lithobius Leach, 1814. Towards
this goal, we (i) examined the epipharynx and hypopharynx of 32 species belonging to four subgenera
of the genus Lithobius, viz. Lithobius Leach, 1814, Monotarsobius Verhoe, 1905, Sigibius Chamberlin,
1913 and Ezembius Chamberlin, 1919 using light and scanning electron microscopy, (ii) searched for
phylogenetically informative characters and (iii) described interspecic variation. ree species of the
lithobiid genera Eupolybothrus Verhoe, 1907, Disphaerobius Attems, 1926 and Neolithobius Stuxberg,
1875 were additionally examined and considered as likely outgroups. New characters and character states
are proposed as additions to current phylogenetic datasets. Similarities in the peristomatic structures ally
Disphaerobius with Lithobius (Ezembius), suggesting that the subfamily Pterygoterginae is nested within
Lithobiinae and Lithobius.
Keywords
Lithobiomorpha, Lithobiidae, epipharynx, hypopharynx, phylogeny, systematics
ZooKeys 741: 49–75 (2018)
doi: 10.3897/zookeys.741.21706
http://zookeys.pensoft.net
Copyright Anne-Sarah Ganske et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC
BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Introduction
e peristomatic structures – the epipharynx and hypopharynx – of Chilopoda have
hitherto been studied in the orders Scutigeromorpha, Lithobiomorpha, Geophilo-
morpha (Koch and Edgecombe 2006, 2008, 2012, respectively), and Scolopendro-
morpha (Edgecombe and Koch 2008, 2009) revealing numerous characters bearing
phylogenetically useful information (see also Koch et al. 2010, Vahtera et al. 2013).
Two characters of the peristomatic structures, viz. ‘bottle-shaped' epidermal glandular
shafts on the epipharynx and a characteristic shape of the hypopharynx, support the
monophyly of the order Lithobiomorpha, whereas paired oblique rows of spines on
the clypeal part of the epipharynx are thought to be apomorphic for the family Litho-
biidae (Koch and Edgecombe 2008). Until now, Lithobius, the most diverse genus in
Chilopoda, with more than 500 described species (Zapparoli and Edgecombe 2011,
Bonato et al. 2016), is resolved as non-monophyletic on the basis of morphological
data. Particular species were recovered in cladistic analysis as most closely related to the
genera Australobius Chamberlin, 1920, Hessebius Verhoe, 1941, and Pleurolithobius
Verhoe, 1899 (Koch and Edgecombe 2008), and this likely applies to other genera
of Lithobiinae as well, if not even some of other ve subfamilies of Lithobiidae (for
current classication of this family see Zapparoli and Edgecombe 2011). However,
broad information on species-interrelationships is still missing and the monophyly
of subgenera remains questionable, being based on combinations of the same set of
characters (Edgecombe 2007). Aiming to obtain further morphological information
from the peristomatic structures of Lithobius to evaluate whether those might be use-
ful for identifying clades within this very large genus, we study the epipharynx and
hypopharynx of 32 species of Lithobius, including the subgenera Lithobius (23 spp.),
Sigibius (3 spp.), Monotarsobius (5 spp.), and Ezembius (1 sp.) using light and scanning
electron microscopy. We describe the variation of the microstructures between species
and propose new characters for which patterns of variability suggest a potential for
phylogenetic analyses. Additionally, we examine species of the lithobiid genera Neo-
lithobius Stuxberg, 1875 (Lithobiinae), Eupolybothrus Verhoe, 1907 (Ethopolyinae),
and Disphaerobius Attems, 1926 (Pterygoterginae), for comparison with Lithobius.
Material and methods
Material
e studied material consists of 61 specimens belonging to 35 species preserved in
70% or 95% EtOH (Table 1), deposited at the Natural History Museum Vienna
(NHMW), the Natural History Museum London (BM/NHMUK) and the Hungar-
ian Natural History Museum Budapest (HNHMB). All material was examined with
light and scanning electron microscopy.

e peristomatic structures of genus Lithobius 51
Table 1. List of studied material deposited in the NHMW, BM/NHMUK and HNHMB.
Species Studied material
Lithobius (Lithobius) agilis
C.L. Koch, 1847
2 females, NHMW 9123, 9124, Austria, Niederösterreich, Gaming,
F.Feiller leg.
L. (L.) calcaratus
C.L. Koch, 1844
1 male, NHMW 9132; 1 female, NHMW 9133, France, Normandie, 1919,
H. Gadeau de Kerville leg.
L. (L.) carinatus L. Koch, 1862 1 female, NHMW 9125, Croatia, Jabuka Island, Pomo, April 1934,
F.Werner & O. Wettstein leg.
L. (L.) castaneus Newport, 1844
1 female, NHMW 9194, N36°12'18", E 9°45'35", Tunisia, Zaghouan
District, Jebel Mansour Mountain, close to (south to) Sidi Aouidette village,
pine forest, Rosmarinus, under stones and leaf litter, 514 m, 28 March 2008,
N. Akkari & P. Stoev leg.
L. (L.) cyrtopus Latzel, 1880 1 female, NHMW 1081, Poland, Galizien (früher zu Ungarn), 1919,
R.Latzel leg.
L. (L.) dentatus C.L. Koch, 1844 2 females, NHMW 9134, 9135, Austria, Wiener Wald
L. (L.) erythrocephalus
C.L. Koch, 1847 2 females, NHMW 9136, 9137, Hungary, Simontornya, F. Pillich leg.
L. (L.) fagei Demange, 1961 1 male, NHMUK, Spain, Majorca, Inca, 1974.242.
L. (L.) forcatus (Linnaeus, 1758) 1 male, NHMW 9138; 1 female, NHMW 9139, Austria, Kärnten, Friedlach,
16 October 2001, V. Stagl leg.
L. (L.) lapidicola Meinert, 1872
1 female, NHMW 9196, N 35°32.796' E 11°1.662', Tunisia, Mahdia
District, Mahdia, touristic area, scattered palm trees and shrubs close to the
road, polluted area not far from agricultural land, under stones, 0 m,
16 March 2008, N. Akkari & P. Stoev leg.
L. (L.) latro Meinert, 1872 2 females, NHMW 9140, 9141, Austria, Tirol, Zillertal, 1950, Schmölzer leg.
L. (L.) lucifugus L. Koch, 1862 2 females, NHMW 9142, 9143, Italy, Südtirol, Sellajoch, 8 August 1896,
C. Attems leg.
L. (L.) macilentus L. Koch, 1862 1 male, NHMW 9144, Austria, Wien, Niederösterreich, Wiener Wald,
18December 1892; 25 March 1894; 5 October 1924, C. Attems leg.
L. (L.) mutabilis L. Koch, 1862 2 females, NHMW 9126, 9127, Czech Republic, Sudetenländer, 1919,
R.Latzel leg.
L. (L.) muticus C.L. Koch, 1847 1 male, NHMW 9145, Slovenia, Maribor (Marburg), C. Attems leg.
L. (L.) nodulipes Latzel, 1880 2 females, NHMW 9146, 9147, Croatia, Küstenland Kroatien, 1919,
R.Latzel leg.
L. (L.) peregrinus Latzel, 1880 1 male, NHMW 9129, Serbia, Šar planina mountain range, Ljubeten
(=Ljuboten mountain), upper beech forest, 4 June 1906, C. Attems leg.
L. (L.) piceus L. Koch, 1862 1 female, NHMW 9128, Austria, österreichische Alpenlande, R. Latzel leg.
L. (L.) pelidnus Haase, 1880
1 male, NHMW 9148, Austria, Wiener Wald, Buch leg.
1male, NHMW 9149, N 48°16'45", E 016°20'10", Austria, Wien,
19. Bezirk, Kastralgemeinde Josefsdorf, Kahlenberg Nordosthang, ca. 400 m
(Wald, unter Holz), 15 June 1980, J. Gruber leg.
L. (L.) pyrenaicus Meinert, 1872 1 male, NHMW 9130; 1 female, NHMW 9131, France, Pyrénées-Orientales,
J. Chalande leg.
L. (L.) tenebrosus Meinert, 1872 2 females, NHMW 9151, 9152, Austria, Kärnten, Bezirk Sankt Veit an der
Glan, Gemeinde Hüttenberg, Pressen (mountain)

Anne-Sarah Ganske et al. / ZooKeys 741: 49–75 (2018)
52
Species Studied material
L. (L.) tricuspis Meinert, 1872 2 females, NHMW 9153, 9154, Austria, Steiermark, Graz, Platte
L. (L.) validus Meinert, 1872 1 female, NHMW 9150, Austria, Steiermark, Weiz, Weizenklamm, 1948,
H. Franz leg.
L. (Monotarsobius) aeruginosus
L. Koch, 1862
2 females, NHMW 7546, Austria, Steiermark, Bezirk Liezen, Admont,
Kemmatgraben, 1949, Franz H. leg.
1 male, HNHMB 5980, Hungary, Felsőszölnök, Hármasfok, beech-
hornbeam forest, 04 August 1948, I. Loksa leg.
L. (M.) austriacus
(Verhoe, 1937)
2 males, HNHMB 5983, 5984, Hungary, Salgóbánya, next to Hotel Medves,
oak-beech forest, 30 March 2003, L. Dányi leg.
L. (M.) crassipes L. Koch, 1862
2 females, NHMW 9157, 9158, Germany, Leipzig, Sturany leg.
2 females, HNHMB 5981, 5982, Hungary, Abaliget, Török-pince Cave (in a
forest), at 8 m from the entrance, 14 January 2012, D. Angyal & L. Dányi leg.
L. (M.) curtipes C.L. Koch, 1847
1 female, HNHMB 5985; 1 male, HNHMB 5986, Hungary, Győrzámoly,
under a woodstem at the side of the dam, 05 October 2000,
L. Dányi, Z. Korsós & A. Seres leg.
L. (M.) franciscorum
Dányi & Tuf, 2012
2 males, HNHMB 5987, 5988, Kazakhstan, Altai Mts., Arshaty, wood near
village, 1200 m a.s.l., 30 June 2007, I.H. Tuf leg.
L. (Sigibius) burzenlandicus
Verhoe,1931
2 males, HNHMB 5989, 5990, N 47°53.456', E 24°31.089', Romania,
Maramureş Mts, Poienile de Sub Munte, Socolǎu valley, mixed forest, 825m
a.s.l., 24 May 2007, Cs. Csuzdi, L. Dányi, J. Kontschán & D. Murányi leg.
L. (S.) microps Meinert, 1868
1 female, 1 male, NHMW 7413, Hungary, Siebenbürgen, 1919, R. Latzel leg.
1 female, HNHMB 5991; 1 male, HNHMB 5992,
N 46.1586°, E 8.8804°, Switzerland, Magadino, Bolle di Magadino, 195m,
under Reynoutria japonica, pitfall trap, 2005-2006, M. Moretti leg.
L. (S.) trebinjanus Verhoe, 1900
1 male, NHMW 9155; 1 female, NHMW 9156,
Albania, Kukes county/Qarku i Kukësit, Has district/Rrethi i Hasit, Pashtrik
mountain range/Mali i Pashtrikut, 1900 m, 1918, A. Penther leg.
L. (Ezembius) electus
Silvestri, 1935
1 female, NHMUK, China, Kara-Korum, Aghill Dabam (Pass), 4700-4800m,
30 August 1988, P. Beron leg.
Neolithobius aztecus
(Humbert & Saussure, 1869) 1 female, NHMUK, BM1894.4.1.75-77, Guatemala, Dr. Stoll leg.
Disphaerobius loricatus
(Sseliwano,1881)
1 male, NHMW 9204, Kazakhstan, East-Kazakhstan Area, Kaigutty River
Valley, 32 km NW Ayagos, Saline-lend, 15 April 2016, A.A. Fomichev,
R.Yu. Dudko leg.
Eupolybothrus (Eupolybothrus)
grossipes (C.L. Koch, 1847)
1 male, NHMW 9176, N 46.4916°, E 14.3488°, Austria, Kärnten, Bezirk
Klagenfurt-Land, Gemeinde Ferlach, Katastralgemeinde Waidisch, 602 m,
rocky beech forest with spruce, under stones, logs and from leaf litter,
25 June 2017, Akkari N., Ganske A.-S. & Dányi L. leg.
Sample preparation
e epipharynx and hypopharynx were dissected from the preoral chamber as described
in Koch and Edgecombe (2008) in one to four adult male or female individuals per
species. Multifocus images of the sclerotized parts of the epipharynx and hypopharynx
were obtained with a Nikon SMZ25 stereomicroscope equipped with a Nikon DS-
F2.5 camera using NIS-Elements Microscope Imaging Software with an Extended

e peristomatic structures of genus Lithobius 53
Depth of Focus (EDF) patch. For scanning electron microscopy (SEM), the specimens
were: (1) cleaned in an ultrasonic bath (50–60 Hz) for 5 to 10 seconds (maximum),
occasionally in a solution of 15% hydrogen peroxide for 2 hours; (2) dehydrated in
an ascending alcohol series (70%, 80%, 90%, 96% EtOH, 2 × 10-15 min each); (3)
air dried overnight (or covered with HMDS) or critical point dried (Leica 300 CPD).
Specimens were mounted on aluminium stubs equipped with a sticky aluminium tape,
glued with conductive silver, coated with platinum (Leica EM SCD500) and studied
with a JEOL JSM 6610-LV at an accelerating voltage of 15 kV. Figures were processed
with Adobe Photoshop CS6 and assembled in Adobe InDesign CS6.
Terminology follows Koch and Edgecombe (2008).
List of abbreviations
bdb – labral bristles on distal bar; blf – labral bristles on lateral ap; bsc – ‘button-
shaped' sensilla; bu – single transverse bulge; bud – distal transverse bulge; bup –
proximal transverse bulge; db – distal bar; gl – ‘bottle-shaped' epidermal glandular
shafts; hb – hypopharyngeal bar; hsp – hypopharyngeal spine eld; lf – lateral ap;
lsp – lateral spine eld; lmc – paired lips forming median crest; mo – mouth opening;
msc – median sensilla cluster; msp – median spine eld; nsc – cluster of ‘nipple-shaped'
sensilla; pb – proximal bar; pp – pharyngeal plate; smc – spines anking median crest;
tu – tuft of bristles; tub – tubercles on distal bar; vlb – ventrolateral bar.
Results
Epipharynx
e epipharynx is distally and proximally bordered by the inner walls of the labrum and
the clypeus, respectively (Fig. 1A). Except for D. loricatus (Fig. 2A), the labral and cly-
peal parts of the epipharynx are generally divided by one or two transverse bulges (distal
and proximal transverse bulge) (Figs 1A, C, 2B–F, 3: bu, bud, bup). e transverse
bulge occurs with a stronger or less pronounced curvature of the furrowed distal and
proximal margins bordering the ‘bottle-shaped' epidermal glandular shafts (Figs1C:
gl, 2B–F, 3A–B). e margins can be parallel or not, curved distally and proximally
(Fig.2B–C) or curved distally and straight proximally (Figs 2D–F, 3A–B). e bulge
always narrows laterally (Figs 2B–F, 3A–B, D, 4D–F, 5A). e surface of the bulge(s) is
generally smooth (Figs 3A, 4A) but in some species it may show longitudinal striae later-
ally (Fig. 4D). In L. tenebrosus and L. lucifugus, the surface of the bulges is longitudinally
striated and shows scattered pores (Figs 3C, 4B–C). In other species, a weak transverse
furrow occurs on the tooth plate distally to the transverse bulge (Fig. 3A–B).
‘Bottle-shaped' epidermal glandular shafts always occur proximal to the transverse
bulge (Fig. 1C: gl). ey can be arranged in one row (Figs 2B, E–F, 5A), one row medi-

Anne-Sarah Ganske et al. / ZooKeys 741: 49–75 (2018)
54
Figure 1. Multifocus light-micrographs and SEM-photographs of peristomatic structures in Lithobiidae.
A Epipharynx of Lithobius (Lithobius) validus; posterior view (top is ventral) B Hypopharynx of Litho-
bius (Lithobius) carinatus; anterior view (top is dorsal) C Epipharynx of Eupolybothrus (Eupolybothrus)
grossipes; posterior view (top is ventral) D Hypopharynx of Lithobius (Lithobius) forcatus; anterodorsal
view (left ventrolateral bar broken). bdb – labral bristles on distal bar, blf – labral bristles on labral ap,
bsc – ‘button-shaped' sensilla, bu – single transverse bulge, bud – distal transverse bulge, bup – proximal
transverse bulge, db – distal bar, gl – ‘bottle-shaped' epidermal glandular shafts, hb – hypopharyngeal bar,
hsp – hypopharyngeal spine eld, lf – lateral ap, lsp – lateral spine eld, lmc – paired lips forming me-
dian crest, mo – mouth opening, msc – median sensilla cluster, msp – median spine eld, nsc – cluster of
‘nipple-shaped' sensilla, pb – proximal bar, pp – pharyngeal plate, smc – spines anking median crest, tp
– tooth plate, tu – tuft of bristles, tub – tubercles on distal bar, vlb – ventrolateral bar. Scale bars: 200 µm.
ally with up to two or more rows on the lateral sides (Figs 2C, 3A, 4A, 5B), or consist-
ently two to more rows (Figs 2A, 3B). e number of glandular shafts varies from 19
in L. microps to more than 80 in L. validus and is generally higher in larger species. e
number of glandular shafts can also dier between individuals of the same species, e.g.
20–22 in L. aeruginosus or 42–48 in L. pyrenaicus.

e peristomatic structures of genus Lithobius 55
Figure 2. Details of transverse bulge, ‘bottle-shaped' epidermal glandular shafts and median spine
eld of the epipharynx of Lithobiidae. A Disphaerobius loricatus; no transverse bulge; consistently two
rows of ‘bottle-shaped' epidermal glandular shafts; narrow and slightly medially widening median spine
eld BLithobius (Lithobius) pyrenaicus; parallel aligned margins of a single transverse bulge; one row of
‘bottle-shaped' epidermal glandular shafts; rhomboid and medially widening median spine eld C Litho-
bius (Lithobius) fagei; single transverse bulge with parallel margins; more than one row of ‘bottle-shaped'
epidermal glandular shafts laterally; laterally widening median spine eld D Lithobius (Sigibius) microps;
single transverse bulge with non-parallel margins; subequal width of median spine eld E Lithobius
(Lithobius) mutabilis; single transverse bulge with non-parallel margins; one row of ‘bottle-shaped' epi-
dermal glandular shafts; subequal width of median spine eld F Lithobius (Monotarsobius) aeruginosus;
single transverse bulge with non-parallel margins; one row of ‘bottle-shaped' epidermal glandular shafts;
subequal width of median spine eld. bu – transverse bulge, gl – ‘bottle-shaped' epidermal glandular
shafts, msp – median spine eld.

Anne-Sarah Ganske et al. / ZooKeys 741: 49–75 (2018)
56
Figure 3. Details of transverse bulge, ‘bottle-shaped' epidermal glandular shafts and median spine eld
of the epipharynx of Lithobiidae. A Lithobius (Lithobius) macilentus; single transverse bulge with smooth
surface (see Fig. 4A) and non-parallel aligned margins; one row of ‘bottle-shaped' epidermal glandular shafts
medially with a transition to two rows laterally (see Fig. 4A); weak transverse furrow distally to the transverse
bulge (arrow); laterally widening median spine eld B Lithobius (Lithobius) piceus; weak transverse furrow
(arrow) distally to the single transverse bulge (non-parallel margins); irregular two rows of ‘bottle-shaped'
epidermal glandular shafts; subequal width medially and laterally of median spine eld CLithobius (Litho-
bius) lucifugus; distal and proximal transverse bulges with surface striation (see Fig.4B–C) D Eupolybothrus
(Eupolybothrus) grossipes; distal and proximal transverse bulges; medially widening median spine eld. bu–
transverse bulge, bud – distal transverse bulge, bup – proximal transverse bulge, gl – ‘bottle-shaped' epider-
mal glandular shafts, msp – median spine eld.
Proximal to the ‘bottle-shaped' epidermal glandular shafts is a median spine eld
arranged as a wide or a narrow band with a subequal width, medially or laterally wid-
ened and consisting of a variable number of branching spines (Figs 1A, C, 2, 3A–B, D:
msp, 5D, 6A, D). e spines are always directed towards the labral part of the epiphar-
ynx but dier in shape, size and texture. e shape can be scaly, apically furcated or
not (Figs 5D, 6).
Paired labral bristle bands occur on the distal bars on each side of the tooth plate
(Fig. 1C: bdb). e bristle bands consist of long, simple bristles medially with a gradual
transition to branching bristles laterally (Fig. 7). e branching bristles occur with a few
or several outer rows, more or less covering the distal bar (Fig. 7A–B). e bristles point
dorsomediad towards the transverse bulge. e branching bristles on the distal bar of
the outer rows are generally ‘hassock-like' (Fig. 8A–C), but they can also be ‘palmleaf-

e peristomatic structures of genus Lithobius 57
Figure 4. Epipharyngeal structures of Lithobius. A Lithobius (Lithobius) macilentus; transverse bulge
with a smooth surface; two rows of epidermal glandular shafts at the lateral border of the transverse bulge
BLithobius (Lithobius) lucifugus; distal transverse bulge with longitudinal striae C Lithobius (Lithobius) lu-
cifugus; proximal transverse bulge with longitudinal striae and pores (arrow) D Lithobius (Lithobius) fagei;
longitudinal striae on the lateral part of the transverse bulge (arrow); continuous branching bristle band
from the distal bar to the lateral ap at the margin of the transverse bulge E Lithobius (Lithobius) cyrtopus;
distinct break of branching bristle band from the distal bar to the lateral ap F Lithobius (Monotarsobius)
crassipes; distinct break of branching bristle band from the distal bar to the lateral ap. bu – transverse
bulge, gl – ‘bottle-shaped' epidermal glandular shafts.
like' as for L. validus (Fig. 8D) or ‘comb-like' in L. trebinjanus (Fig. 8E). e base of the
branching bristles ranges from narrow to wide, with intermediate forms (Fig. 8).
e labral branching bristles on the distal bar expand towards the proximal part in a
continuous manner (Fig. 4D) or with a distinct break (Fig. 4E–F) across the transverse

Anne-Sarah Ganske et al. / ZooKeys 741: 49–75 (2018)
58
Figure 5. Epipharyngeal structures of Lithobius. A Lithobius (Lithobius) pyrenaicus; one row of ‘bottle-
shaped' epidermal glandular shafts; laterally narrowing transverse bulge B–C Lithobius (Lithobius) validus
B two rows of ‘bottle-shaped' epidermal glandular shafts C pore of an epidermal glandular shaft (arrow)
D Lithobius (Ezembius) electus; broad median spine eld with several rows of branching bristles and a sub-
equal width medially and laterally. bu – transverse bulge, gl – ‘bottle-shaped' epidermal glandular shafts.
bulge to the labral ap margins (Fig. 1C: blf). On the lateral ap, the structure of labral
bristles changes gradually from laterally plumose to medially ‘fan-shaped' (Fig.9A–C)
or it is consistently plumose (Fig. 9D), ‘fan-shaped' only (Fig. 9E), or they can show just
as simple bristles (Fig. 9F).
On the lateral borders of the distal bar, ovoid tubercles are observed in nearly all
investigated species (Figs 1C: tub, 10H).
e median sensilla cluster (Fig. 1C: msc) on the clypeal part is always transversely
aligned. It displays a highly variable interspecic arrangement of the sensilla. ese
sensilla can be arranged in line (Fig. 10A inset), in an oset-pattern (Fig. 10A, C–D)
or symmetrical (Fig. 10B). e number of sensilla in the studied species varies between
ve in L. aeruginosus to 65 in E. grossipes (Fig. 10D). Variation of the arrangement and
number of sensilla is also recorded in individuals of the same species (e.g. L. tenebrosus
and L. aeruginosus).
Proximal to the clypeal part pairwise lateral spine elds are present bordering the me-
dian sensilla cluster except for N. aztecus (Fig. 10C), D. loricatus and E. grossipes (Fig.10D)
in which the sensilla overlap with the spine elds (Fig. 1C: lsp). e lateral spine elds are
arranged in one oblique row or more than one row (Fig. 10A-G). If there is more than

e peristomatic structures of genus Lithobius 59
Figure 6. Details of spines from the median spine eld on the epipharynx of Lithobius. A Lithobius
(Monotarsobius) aeruginosus; narrow median spine eld with a few rows of branching spines B Lithobius
(Lithobius) macilentus C Lithobius (Lithobius) peregrinus D Lithobius (Lithobius) tricuspis. msp – median
spine eld. Scale bars: 5 µm.
one row there is a tendency for spines to cluster or form small groups (Fig. 10E). ese
spines are surrounded by pores (Fig. 10E) and vary in number from two per side in L.
peregrinus to approximately 17 in L. crassipes. ey always point proximomediad towards
the mouth opening and show a dissimilarity in number and distribution per side within a
single individual. e spines are mainly long and tapering, with shorter ones in between
(Fig. 10A–G). In some other species, they can be bi- or trifurcate (Fig. 10B, E).
Hypopharynx
e hypopharynx is a subtriangular outgrowth consisting of paired lips forming a me-
dian crest (Fig. 1B, D: lmc). In front of the mouth opening lies the pharyngeal plate
(Schlundplatte after Verhoe 1902-1925) (Figs 1B, D, 11A: mo, pp). e latter shows
transversely arranged ‘nipple-shaped' sensilla on its median part (Figs 1D, 11A: nsc).
e number of these sensilla varies from ve in L. aeruginosus (Fig. 11B) to 25 in L.
validus (Fig. 11D). e distribution pattern of ‘nipple-shaped' sensilla varies from one
clear line (Fig. 11A–B), zig-zag (Fig. 11C) to clusters of sensilla (Fig. 11E–F) but also
displays intermediate forms (Fig. 11D).

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Figure 7. Labral bristle bands on the distal bar of the epipharynx of Lithobius. A Lithobius (Lithobius)
lucifugus; transition of simple to branching bristles from medial to lateral with a few rows of branching
bristles B Lithobius (Lithobius) peregrinus; transition of simple to branching bristles from medial to lateral
with several rows of branching bristles C Lithobius (Lithobius) erythrocephalus; detail of the transition of
simple to branching bristles from medial to lateral D Lithobius (Lithobius) lucifugus; simple bristles on the
medial part of the distal bar (top is medial).
Distal to the pharyngeal plate appears a ‘tuft-like' cluster of branching bristles
(Fig. 1D: tu). e shape of these branching bristles varies from ‘fan-shaped' to ram-
ied, with a more attened or roundish shaft occurring with several intermediate
forms (Figs 12, 13C).
Lateral to the pharyngeal plate, hypopharyngeal spines are always present (Figs 1D,
11A, 12A: hsp). ey are arranged in clusters of ve to 37 spines unilaterally (Fig.13A–C)
and they are surrounded with single or clustered pores (up to six) from apparently epidermal
glands (Fig. 13A–B, D, F). e spines mainly taper (Figs 11A, 13A–D, F), sometimes with
ridges along the lateral side of the spine shaft (Fig. 13E) or are apically furcate (Fig.13A).
ey can be long or short, sometimes with a more attened appearance (Figs11A, 13). e
hypopharyngeal spines may occur with a continuous transition distomedially to the tuft
area (Fig. 13A) or with a distinct break (Fig. 13C).
‘Button-shaped' sensilla are arranged in continuous clusters on the lips of the me-
dian crest medially up to the ventrolateral bars within the branching bristles and are
present in all examined species (Figs 1D: bsc, 14, 16B–D). e median crest is anked
by intergrading rows of branching bristles (Fig. 1D: smc), which can be stout and
short (Fig. 15D) or slender and long (Fig. 15E). In several species, we observed a

e peristomatic structures of genus Lithobius 61
Figure 8. Details of branching bristles on the outer row of the labral bristle bands on the distal bar of
the epipharynx of Lithobius. A–B ‘hassock-like' branching bristles with a broad base A Lithobius (Litho-
bius) mutabilis B Lithobius (Ezembius) electus C Lithobius (Lithobius) pyrenaicus; ‘hassock-like' branching
bristles with a narrow base D Lithobius (Lithobius) validus; ‘palmleaf-like' bristles E Lithobius (Sigibius)
trebinjanus; ‘comb-like' bristles (top is medial).
transition from branching bristles to attened spines on the outermost rows (Figs 14A,
15A–C,F). e attened spines show a structured surface (Fig. 15C).
e trichomes on the paired lips forming the median crest exhibit an intergrading tran-
sition from the tuft area proximal to distal up to the tips of the ventrolateral bars and medi-
ally to the proximoventral parts of the hypopharynx (Fig. 1D). At the border to the tuft
area, there are generally ‘fan-shaped' or plumose branching bristles, which mostly shorten
in length, transitioning to ‘brush-', ‘tuft-', ‘feather-like' or simple bristles (Figs 14A, 15A,
E–F, 16A–C, E–F, 17A–D, F). On the proximoventral part, the bristles change over into
clearly separated brush-tufts that are intermingled by ‘button-shaped' sensilla (Fig. 16D).
e shape of trichomes varies greatly between species. In D. loricatus, for example, there are
scales on the distal tips of the lips bordered by the margin of the ventrolateral bar (Fig. 17E)
in comparison to other species showing bristles in this area (Fig. 17A–D, F).
Peristomatic characters with phylogenetic signicance
In the following, eight peristomatic characters are proposed for the genus Lithobius,
three of which are newly described (see char. 4, 6, 7). Additionally, we veried the
consistency of two characters (see char. 2, 8) and adjusted three (see char. 1, 3, 5) from
those indicated by Koch and Edgecombe (2008). Codings are provided in Appendix 1.

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Figure 9. Details of branching bristles on the lateral ap on the distal bar of the epipharynx of Litho-
bius. A–B Lithobius (Lithobius) fagei A bristles changing from plumose laterally to ‘fan-shaped' medially
Bdetail of 9A C Lithobius (Monotarsobius) aeruginosus; bristles changing from plumose laterally to ‘fan-
shaped' medially D Lithobius (Lithobius) peregrinus; plumose bristles only E Lithobius (Lithobius) cyrtopus;
‘fan-shaped' bristles only F Disphaerobius loricatus; simple bristles only (top is medial).
Epipharynx
1. ‘Bottle-shaped' glandular shafts at the border between labral and clypeal part of
epipharynx: (0) one distinct regular row; (1) more than one regular or irregular row.
All the investigated lithobiomorph species possess ‘bottle-shaped' epider-
mal glandular shafts at the border between the labral and clypeal parts of the
epipharynx. e latter can be in one regular row (Figs 2B, D–F, 5A) or with
a variable arrangement, e.g. one regular row medially, which expands to two

e peristomatic structures of genus Lithobius 63
Figure 10. Median sensilla cluster and lateral spine elds on the epipharynx of Lithobiidae. A Lithobius
(Lithobius) validus; sensilla cluster arranged in an oset pattern; spine eld arranged as single oblique row;
Inset: Lithobius (Monotarsobius) aeruginosus; sensilla cluster arranged in line B Lithobius (Lithobius) ten-
ebrosus; sensilla cluster arranged symmetrically; spine eld arranged as single oblique row with trifurcate
spines (arrow) C Neolithobius aztecus; sensilla cluster arranged in an oset pattern; spine eld arranged as
single oblique row D Eupolybothrus (Eupolybothrus) grossipes; sensilla cluster arranged in an oset-pattern
and strongly overlapping with lateral spine eld proximolaterally; spine eld arranged as single oblique row
E Lithobius (Lithobius) pelidnus; spine eld arranged as two rows (tendency of clustering) with bi- or trifur-
cate spines (arrows) and pores (asterisks) F Lithobius (Monotarsobius) curtipes; spine eld arranged as single
oblique row G Lithobius (Monotarsobius) aeruginosus; spine eld arranged as single oblique row H Lithobius
(Monotarsobius) aeruginosus; tubercles on distal bar. lsp – lateral spine eld, msc – median sensilla cluster.

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Figure 11. ‘Nipple-shaped' sensilla on pharyngeal plate and hypopharyngeal spines of hypopharynx of
Lithobius. A Lithobius (Lithobius) dentatus; pairwise hypopharyngeal spine elds laterally to pharyngeal plate;
transverse line of several ‘nipple-shaped' sensilla B Lithobius (Monotarsobius) aeruginosus; transverse line of a
few ‘nipple-shaped' sensilla on the pharyngeal plate; arrow indicates a pore C Lithobius (Lithobius) pyrenaicus;
‘nipple-shaped' sensilla arranged in a zig-zag-pattern D Lithobius (Lithobius) validus; several ‘nipple-shaped'
sensilla arranged in a transverse line with some oset sensilla E–F Lithobius (Lithobius) forcatus E clustered
‘nipple-shaped' sensilla F high magnication of ‘nipple-shaped' sensilla from Fig.11E. hsp – hypopharyngeal
spine eld, mo – mouth opening, nsc – cluster of ‘nipple-shaped' sensilla, pp – pharyngeal plate.
or three regular or irregular rows laterally (Figs 2C, 3A, 4A, 5B). A regular or
irregular arrangement of consistently two or more rows along the whole width
is present, for example, for D. loricatus and L. piceus (Figs 2A, 3B). Both states
were identied across all subgenera of Lithobius with state (0) being underrep-
resented in the subgenus Lithobius (6 of 23 examined species). N. aztecus, D.
loricatus (Fig. 2A) and E. grossipes (Fig. 3D) share state (1).
2. Labral bristle bands of epipharynx: (0) bristle bands continuous across trans-
verse bulge; (1) distinct break in bristle bands proximal and distal to transverse
bulge. (Character 31 in Koch and Edgecombe 2008).

e peristomatic structures of genus Lithobius 65
Figure 12. Shapes of branching bristles forming a tuft distally to the pharyngeal plate of the hypophar-
ynx of Lithobiidae. A Lithobius (Lithobius) forcatus; ramied branching bristles with a roundish shaft
and hypopharyngeal spines laterally to pharyngeal plate (top is dorsal) B Lithobius (Lithobius) calcaratus;
close-up of ‘fan-shaped' and attened branching bristles (top is medial) C Eupolybothrus (Eupolybothrus)
grossipes; ramied and more attened branching bristles (top is dorsal) D Lithobius (Lithobius) latro; rami-
ed and at branching bristles (top is medial). hsp – hypopharyngeal spine eld.
e subgenera of Lithobius and other lithobiid genera show labral bristle bands that
are either continuous (Fig. 4D) or are interrupted at the transverse bulge (Fig.4E–F).
All studied species of the subgenus Sigibius share state (1) (e.g. Fig. 2D).
3. Number of transverse bulge(s) at border between labral and clypeal parts of
epipharynx: (0) none; (1) one; (2) two.
e presence of one or two transverse bulges is common for the genera Litho-
bius, Neolithobius and Eupolybothrus (e.g. Figs 2B–F, 3). e bulges are absent
only in the genus Disphaerobius (Fig. 2A). Two bulges are shared by L. calcara-
tus, L. lucifugus, L. tenebrosus and E. grossipes only (e.g. Fig. 3C–D).
4. Direction of distal and proximal furrowed margins of transverse bulge or trans-
verse bulges on epipharynx: (0) parallel; (1) non-parallel.
Both states occur in all studied genera, state (0) e.g. in L. pyrenaicus, L. fagei,
L. lucifugus and E. grossipes (Figs 2B–C, 3C–D) or state (1) e.g. in L. microps,
L. mutabilis, L. aeruginosus, L. macilentus and L. piceus (Figs 2D–F, 3A–B). All
species of the subgenus Sigibius share a non-parallel alignment (state (1)) of the
transverse bulge margins (e.g. L. microps; Fig. 2D).

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Figure 13. Examples of number and shape of the hypopharyngeal spines and surrounding pores of
Lithobiidae. A Eupolybothrus (Eupolybothrus) grossipes; several tapering spines with trifurcate spines (as-
terisks) in between and a continuous transition to the tuft area (arrow) B Lithobius (Lithobius) agilis;
few short tapering spines; several single pores C Lithobius (Lithobius) muticus; long and tapering spines;
distinct break (arrow) between hypopharyngeal spine eld and branching bristles of tuft D Lithobius
(Lithobius) validus; hypopharyngeal spines surrounded by cluster of up to six pores (arrow) E Lithobius
(Lithobius) cyrtopus; attened and ridged spines F Lithobius (Lithobius) castaneus; detail of a long tapering
spine close to a single pore (arrow). hsp – hypopharyngeal spine eld, tu – tuft of bristles.
5. Median eld of branching spines immediately proximal to the border between
labral and clypeal parts of epipharynx: (0) rhomboid, widening medially; (1)
widening laterally; (2) subequal width medially and laterally.
State (2) is most common throughout the subgenus Lithobius and occurs
in the other subgenera of Lithobius, e.g. L. microps, L. piceus and L. electus
(Figs2D, 3B, 5D). e genera Eupolybothrus, Disphaerobius and Neolithobius
share state (0) but show variation in the number of rows of branching spines

e peristomatic structures of genus Lithobius 67
Figure 14. Examples of ‘button-shaped' sensilla on the lips of hypopharynx of Lithobiidae. A Lithobius
(Lithobius) forcatus; proximal part of lips forming median crest with cluster of ‘button-shaped' sen-
silla; attened spines anking median crest margin B Eupolybothrus (Eupolybothrus) grossipes; left lip with
cluster of ‘button-shaped' sensilla C Lithobius (Lithobius) validus D Lithobius (Sigibius) burzenlandicus
ELithobius (Lithobius) muticus F Lithobius (Lithobius) carinatus. bsc – ‘button-shaped' sensilla, smc –
spines anking median crest, tu – tuft of bristles. A top is dorsal; B–F top is medial.
(e.g. Figs2A,3D). All states occur with a narrower or wider band having a few
or several rows of branching spines.
6. Shape of branching bristles on labral ap of epipharynx: (0) lateral to medial
transition from plumose to ‘fan-shaped' bristles; (1) ‘fan-shaped' bristles only;
(2) plumose bristles only; (3) simple bristles only.
A transition of branching bristles from plumose laterally to ‘fan-shaped' medi-
ally is the most common state (0) across the genus Lithobius, and also pertains
to Neolithobius and Eupolybothrus (e.g. Fig. 9A–C). State (1) was observed in

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Figure 15. Examples of spines and bristles anking the median crest margins of hypopharynx of Litho-
bius. A–C attened spines with a transition to branching bristles on the inner rows A Lithobius (Litho-
bius) pelidnus B Lithobius (Monotarsobius) franciscorum C Lithobius (Lithobius) muticus; Inset: detail of
structured surface of attened spines D–E continuously branching bristles anking the median crest
DLithobius (Sigibius) microps; stout and short branching bristles E Lithobius (Lithobius) piceus; slender and
long branching bristles F Lithobius (Lithobius) forcatus; attened spines anking median crest margin.
A–B, D–E top is medial; C top is ventral; F top is dorsal.
L.cyrtopus (Fig. 9E), L. lucifugus, L. pelidnus and L. microps. State (2) was pre-
sent in L. peregrinus (Fig. 9D), L. piceus and L. tricuspis, and state (3) in D.
loricatus only (Fig. 9F).
7. Lateral expansion of median sensilla cluster of epipharynx: (0) isolated from
the lateral spine elds; (1) partly overlapping with the lateral spine elds.

e peristomatic structures of genus Lithobius 69
Figure 16. Examples of bristles transitioning in shape and length along the median crest margin on hy-
popharynx of Lithobius. A–B Lithobius (Lithobius) forcatus B ‘button-shaped' sensilla between branch-
ing bristles on the distal part of the lips C Lithobius (Lithobius) pyrenaicus D Lithobius (Lithobius) erythro-
cephalus; Inset: detail of brush-tufts surrounding ‘button-shaped' sensilla E Lithobius (Lithobius) pelidnus
F Lithobius (Lithobius) carinatus.
In all Lithobius species we examined (except for L. tricuspis and L. nodulipes
for which the samples were damaged), the median sensilla cluster is bor-
dered laterally by elds of spines (state (0); Fig. 10A–B). e sensilla in D.
loricatus and N. aztecus slightly overlap with the lateral spine elds medially
(state (1); e.g. Fig. 10C). In E. grossipes the sensilla of the median sensilla
cluster strongly overlap with the lateral spine elds proximolaterally (state
(1); Fig. 10D).

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Figure 17. Bristles and scales on the distal tips of the lips on hypopharynx of Lithobiidae. A Lithobius
(Lithobius) cyrtopus B Lithobius (Lithobius) pelidnus C Lithobius (Lithobius) validus D Eupolybothrus (Eu-
polybothrus) grossipes E Disphaerobius loricatus; scales F Lithobius (Lithobius) forcatus. Scale bars: 20 µm.
8. Dierentiation of spines anking median crest of hypopharynx: (0) intergrad-
ing rows of branching bristles; (1) single outer row of simple attened spines
with abrupt transition to multifurcating inner rows of branching bristles.
(Character 39 in Koch and Edgecombe 2008)
Species of the subgenus Monotarsobius always display state (1) (e.g. L. francisco-
rum; Fig. 15B). e Ezembius species L. electus studied here displays state (1),
which diers from Lithobius (Ezembius) giganteus Sseliwano, 1881, stated
by Koch and Edgecombe (2008). State (1) (Fig. 15A–C, F) is more common
throughout the other subgenera of Lithobius and species of the other examined
genera compared to state (0) (Fig. 15D–E).

e peristomatic structures of genus Lithobius 71
Discussion
Studies on the external morphology and microanatomy of the peristomatic struc-
tures of centipedes have hitherto unveiled phylogenetically useful information (Koch
and Edgecombe 2006, 2008, 2012, Edgecombe and Koch 2008, 2009). e ‘bottle-
shaped' epidermal glandular shafts of the epipharynx and the discrete shape of the
hypopharynx support the monophyly of the order Lithobiomorpha and paired oblique
rows of lateral spines on the clypeal part of the epipharynx is, for example, considered
as an apomorphic character for the family Lithobiidae (Koch and Edgecombe 2008).
e inclusion of characters from these structures in a morphological dataset that also
included other (mostly external) parts of the body further revealed the genus Litho-
bius as a non-monophyletic taxon (Koch and Edgecombe 2008). Within the genus
Lithobius, ve out of eleven described characters of the peristomatic structures dis-
play dierent states (Koch and Edgecombe 2008), which might give hints on species-
interrelationships within the genus. ese data from the peristomatic structures are
presented as a set of coded characters (Appendix 1) that will be analysed cladistically
with characters from other character systems in a later study.
Phylogenetic signicance of the peristomatic structures of Lithobiidae
While studying the peristomatic structures of Lithobiomorpha and Scutigeromorpha,
Koch and Edgecombe (2008) compared the presence of the ‘bottle-shaped' epidermal
glandular shafts between the labral and clypeal part of the epipharynx. ese glandular
shafts were reported to be constantly present in Lithobiomorpha (Koch and Edge-
combe 2008) and absent in other chilopods (Koch and Edgecombe 2006, 2008, 2012,
Edgecombe and Koch 2008). We conrmed the presence of glandular shafts in the
specimens we examined in the lithobiid genera Lithobius, Neolithobius, Eupolybothrus
and Disphaerobius and further recorded dierences in number and regularity of rows
(character 1).
e same authors (Koch and Edgecombe 2008) described the presence of a trans-
verse bulge dividing the labral and clypeal part on the epipharynx for all Lithobiomor-
pha except for Hessebius plumatus Zalesskaja, 1978 and L. (Ezembius) giganteus dis-
playing no bulge at all. is study conrms the absence of the bulge in the species D.
loricatus (Fig. 2A) and for the rst time the presence of a second bulge (distal transverse
bulge) as recorded for the species L. calcaratus, L. lucifugus, L. tenebrosus and E. gros-
sipes as well as E. fasciatus (Newport, 1845) (specimens used by Koch and Edgecombe
2008). e alignment of the bulges is further described and proposed as an additional
character state (character 4).
e examination of additional taxa within Lithobiidae revealed more variation
in the shape of the median spine eld than previously described and having surveyed
more species we include additional character states to those already described by Koch
and Edgecombe (2008) (character 5).

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Although dierences in shape of the bristles on the labral ap were briey men-
tioned by Koch and Edgecombe (2008), our study unveiled four consistent states in
the shape of bristles and transition of those from laterally to medially, which serves as
a new multistate character for Lithobiidae (character 6). A transition of bristles from
plumose to ‘fan-shaped' was described for Pleurolithobius patriarchalis (Berlese, 1894)
(Koch and Edgecombe 2008), as in the majority of the investigated species in the
present study. In contrast, only ‘fan-shaped' bristles are observed in the lithobiid Har-
polithobius anodus (Latzel, 1880) and the henicopid Lamyctes (Lamyctes) emarginatus
(Newport, 1844). On the other hand, the interpretation that Lithobius (Monotarso-
bius) holstii (Pocock, 1895) possesses only ‘fan-shaped' bristles (Fig. 6E in Koch and
Edgecombe 2008) seems erroneous as their gure reveals a pattern in accordance with
the other examined Monotarsobius-species, which exhibit a transition from plumose to
‘fan-shaped' bristles (e.g. L. aeruginosus, Fig. 9C).
Generally, the median sensilla cluster borders or overlaps marginally with the lat-
eral eld of spines in Lithobiomorpha (Koch and Edgecombe 2008). However, we ob-
served a median sensilla cluster considerably expanding along the length of the lateral
spine elds on the epipharynx in E. grossipes for Lithobiomorpha (Fig. 10D). is was
also veried in E. fasciatus (specimens used by Koch and Edgecombe 2008), which also
displays a large but partial overlap.
As mentioned in the introduction, the hypopharynx as a short outgrowth with a
median crest is an apomorphic character for Lithobiomorpha. is is veried in all
examined lithobiid species. Moreover, the median crest margin of all studied species
of the subgenus Monotarsobius displays attened spines (character 8) as previously de-
scribed for L. holstii (Koch and Edgecombe 2008).
Variability of the peristomatic structures in Lithobiidae
Besides the well-dened characters listed in the previous paragraph, our investigation
also yielded several structures with high variability in appearance and/or intermedi-
ate forms between and even within species. For example, the branching bristles of (i)
the labral bristle band on the distal bar, (ii) the spines of the median spine eld of the
epipharynx and (iii) the branching bristles as a tuft on the hypopharynx occur with
several non-denable forms. Koch and Edgecombe (2008) described a smooth trans-
verse bulge for Lithobiidae, which we conrmed for most of the examined species.
However, we also observed a longitudinal striation of the whole bulge surface or at least
on the lateral parts of the bulge for some species (Figs 3C, 4D). A similar description
of the latter state was observed for the henicopid Lamyctes emarginatus, where more
dened longitudinal grooves occur (Koch and Edgecombe 2008).
e paired oblique rows of elongated lateral spines on the clypeal part of the
epipharynx were also considered as an apomorphic character for Lithobiidae (Koch
and Edgecombe 2008). is is also conrmed in all examined lithobiid species we

e peristomatic structures of genus Lithobius 73
studied. However, the proposed character states, i.e. (2): oblique rows of single spines
and (3): a few small groups of branching spines for the lateral eld of spines on Litho-
biidae were not consistent across the species we examined and showed many interme-
diate states. On this basis we excluded the character for conclusions on the systematics
in Lithobiidae, especially Lithobius, in our study.
Koch and Edgecombe (2008) recorded groups of lateral elds of spines in the
subgenus Monotarsobius in contrast to pairs of oblique rows in the rest of Lithobiidae
(character 32, state (3)). ese spines seem to be arranged in oblique rows as in the
rest of Lithobiidae in the species L. (Monotarsobius) aeruginosus and L. (Monotarsobius)
curtipes (Fig. 10F–G).
A correlation between the number of ‘bottle-shaped' epidermal glandular shafts of
Lithobiomorpha and body size was also mentioned by Koch and Edgecombe (2008),
implying that larger species tend to have higher numbers. Here, we suggest the same
for the number of glandular shafts, sensilla in the median sensilla cluster and the ‘nip-
ple-shaped' sensilla cluster, lateral spines, and the hypopharyngeal spines. is size
correlation needs to be conrmed by morphometrics and statistical analysis but the
phylogenetic signicance of these characters is cast into doubt.
Assumptions on the relationship of Disphaerobius with (sub)genera Lithobius
and Ezembius
e peristomatic structures of H. plumatus and L. (Ezembius) giganteus described by
Koch and Edgecombe (2008) and D. loricatus examined in this study, i.e. a missing
transverse bulge (character 3), simple bristles on the labral ap of the epipharynx
(character 6) and scales on the distal tips of the lips of the hypopharynx (Fig. 17E),
dier from all other studied species of Lithobius, including L. (Ezembius) electus, even
if the latter is correctly placed in the subgenus Ezembius. Several taxa in Central
Asia, also species of the giganteus-group of Lithobius (Eason 1983, 1986) and of the
genus Hessebius Verhoe, 1941 share some morphological characters with the genus
Disphaerobius Attems, 1926, as mentioned by Farzalieva et al. (2017): “… function-
ally biarticulated tarsi of leg 1–13, the antennae composed of 20 antennomeres, the
rounded posterior angles of all tergites, the 1-segmented male gonopods, and Tömös-
váry's organ being equal in size to the nearest ocellus or smaller.” In contrast to the
three other species of the giganteus-group of Lithobius, L. (Ezembius) giganteus dis-
plays secondary sexual modications of the tergites in males similar to Disphaerobius
(Farzalieva et al. 2017). Here, we assume that the epipharyngeal and hypopharyngeal
structures may conrm a closer relationship of L. (Ezembius) giganteus to D. loricatus
than to L. (Ezembius) electus. is relationship is inconsistent with the classication
of Disphaerobius as a separate subfamily, Pterygoterginae Verhoe, 1933, because that
classication would render Lithobiinae, as well as Lithobius and L. (Ezembius) as para-
phyletic groups.

Anne-Sarah Ganske et al. / ZooKeys 741: 49–75 (2018)
74
Acknowledgements
is project has received funding from the European Union's Horizon 2020 research
and innovation programme under the Marie Sklodowska-Curie grant agreement No
642241. Critical point drying (Leica 300CPD) for some specimens was performed
at the Core Facility Cell Imaging and Ultrastructure Research, University of Vienna.
anks are due to Dan Topa for support with the SEM and the sputter coater and to
Edmund Schiller for inventorying and incorporating the specimens in the collections.
We are grateful to Làszlò Dànyi (HNHM Budapest) and Gyulli Farzalieva (Perm State
University) for providing specimens for research. Andy Sombke, Markus Koch and
Marzio Zapparoli provided helpful comments on a previous version of the manuscript
and Markus Koch shared additional unpublished SEM images of E. fasciatus.
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Appendix 1
Data matrix of 8 peristomatic characters of Lithobiidae, numbered as in the text.
Species Characters
12345678
L. (L.) agilis 111(0?)1000
L. (L.) calcaratus 11212000
L. (L.) carinatus 10111000
L. (L.) castaneus 10102000
L. (L.) cyrtopus 01110101
L. (L.) dentatus 11112000
L. (L.) erythrocephalus 11112001
L. (L.) fagei 10101000
L. (L.) forcatus 10100001
L. (L.) lapidicola 01112001
L. (L.) latro 11112001
L. (L.) lucifugus 11202101
L. (L.) macilentus 11111001
L. (L.) mutabilis 01112001
L. (L.) muticus 00110001
L. (L.) nodulipes 111110?1
L. (L.) peregrinus 10100200
Species Characters
L. (L.) piceus 10112200
L. (L.) pelidnus 11102101
L. (L.) pyrenaicus 00100001
L. (L.) tenebrosus 0121200?
L. (L.) tricuspis 101022?0
L. (L.) validus 10101001
L. (M.) aeruginosus 01112001
L. (M.) austriacus 01111001
L. (M.) crassipes 01112001
L. (M.) curtipes 10111001
L. (M.) franciscorum (1?)1110001
L. (S.) burzenlandicus 0111?000
L. (S.) microps 01112100
L. (S.) trebinjanus 11111001
L. (E.) electus 10102001
N. aztecus 11100011
D. loricatus 100-0311
E. (E.) grossipes 10200010